# Patent

## Title
Treatment of erythropoietin (EPO) related diseases by inhibition of natural antisense transcript to EPO

## Abstract

Oligonucleotide compounds modulate expression and/or function of Erythropoietin (EPO) polynucleotides and encoded products thereof. Methods for treating diseases associated with Erythropoietin (EPO) comprise administering one or more oligonucleotide compounds designed to inhibit the EPO natural antisense transcript to patients.

## Background
PRIORITY CLAIM
This application is a Divisional of U.S. Ser. No. 13/133,025 filed Jun. 15, 2011, now U.S. Pat. No. 8,921,329, which is a National Phase Entry of PCT/US2009/066659 filed on Dec. 3, 2009, which claims priority to U.S. Provisional Application No. 61/119,961 filed on Dec. 4, 2008, which are all incorporated herein by reference in their entireties,


FIELD OF THE INVENTION
Embodiments of the invention comprise oligonucleotides modulating expression and/or function of EPO and associated molecules.
BACKGROUND
DNA-RNA and RNA-RNA hybridization are important to many aspects of nucleic acid function including DNA replication, transcription, and translation. Hybridization is also central to a variety of technologies that either detect a particular nucleic acid or alter its expression. Antisense nucleotides, for example, disrupt gene expression by hybridizing to target RNA, thereby interfering with RNA splicing, transcription, translation, and replication. Antisense DNA has the added feature that DNA-RNA hybrids serve as a substrate for digestion by ribonuclease H, an activity that is present in most cell types. Antisense molecules can be delivered into cells, as is the case for oligodeoxynucleotides (ODNs), or they can be expressed from endogenous genes as RNA molecules. The FDA recently approved an antisense drug, VITRAVENETM (for treatment of cytomegalovirus retinitis), reflecting that antisense has therapeutic utility.
Enhanced red blood cell production mediated by the hormone erythropoietin (EPO) is a well-known adaptive response of humans to hypoxia (Bunn et al. (1996) Physiological Rev. 76, 839-845). Normally produced by the adult kidney and the fetal liver, EPO stimulates the development of EPO receptor (EpoR) expressing red blood cell precursors in the bone marrow.
EPO is a glycoprotein (46 kDa) hormone produced by renal interstitial cells within the kidney that regulate the production of red blood cells in the marrow. These cells are sensitive to low arterial oxygen concentration and will release erythropoietin when oxygen is low (hypoxia). Erythropoietin stimulates the bone marrow to produce more red blood cells thereby increasing the oxygen carrying capacity of the blood. EPO exerts its effect by binding to EpoR on the surface of erythrocyte precursors in the bone marrow. EPO expression, however, has been observed on the cells from other normal tissues in addition to renal interstitial cells including enterocytes, trophoblast and neuronal cells.
The measurement of EPO in blood stream can indicate bone marrow disorders or kidney disease. Normal levels of erythropoietin are 0 to 19 mU/ml (milliunits per milliliter). Elevated levels can be seen in polycythemia rubra vera, a condition characterized by enlargement of spleen and increased production of red blood cells by bone marrow. Lower than normal values are seen in chronic renal failure leading to anemia. Chronic renal failure leads to anemia, in part, because of the progressive absence of adequate EPO production for the maintenance of erythropoiesis.
Hypoxia is predominant feature of solid tumors, which comprise approximately ninety percent of all human cancers. Adaptive responses to hypoxia in solid tumors has been correlated with enhanced aggressiveness, reduced tumor cell death and diminished tumor response to both radiation and chemotherapy. EPO expression has been observed in different hematopoietic and non-hematopoietic malignancies and has been shown to mediate autonomous growth of erythrocytic leukemia cells expressing EpoR.
Many common human cancers over-express the hypoxia-inducible transcription factor HIF-1, which regulates the expression of EPO as well as several genes required for enhancing hypoxic survival of cancer cells including genes coding for glycolytic enzymes, glucose transporters, and vascular endothelial growth factor (Semenza (1999) Ann. Rev. Cell. Dev. Biol. 15, 551-578). Tumor hypoxia is recognized as a major factor in the tumor resistance to chemotherapy and radiation therapy although the underlying mechanisms are unknown. Hypoxia induces adaptive responses in cells largely by activating the expression of several genes under the regulation of hypoxia-inducible factor-1 (HIF-1), a heterodimeric transcription factor composed of HIF-1α and HIF-1β subunits.
SUMMARY
This Summary is provided to present a summary of the invention to briefly indicate the nature and substance of the invention. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
In one embodiment, the invention provides methods for inhibiting the action of a natural antisense transcript by using antisense oligonucleotide(s) targeted to any region of the natural antisense transcript resulting in up-regulation of the corresponding sense gene. It is also contemplated herein that inhibition of the natural antisense transcript can be achieved by siRNA, ribozymes and small molecules, which are considered to be within the scope of the present invention.
One, embodiment provides a method of modulating function and/or expression of an EPO polynucleotide or other gene product in patient cells or tissues in vivo or in vitro comprising contacting said cells or tissues with at least one antisense oligonucleotide 5 to 30 nucleotides in length wherein said oligonucleotide has at least 50% sequence identity to a reverse complement of a polynucleotide comprising 5 to 30 nucleotides within nucleotides 1 to 156 of SEQ ID NO: 3 (FIG. 3) thereby modulating function and/or expression of the EPO polynucleotide in patient cells or tissues in vivo or in vitro.
In another preferred embodiment, an oligonucleotide targets a natural antisense sequence of EPO polynucleotides, for example, nucleotides set forth in SEQ ID NO: 3, and any variants, alleles, homologs, mutant, derivatives, fragments and complementary sequences thereto. Examples of antisense oligonucleotides are set forth as SEQ ID NOS: 4 to 6 (FIG. 4).
Another embodiment provides a method of modulating function and/or expression of an EPO polynucleotide in patient cells or tissues in vivo or in vitro comprising contacting said cells or tissues with at least one antisense oligonucleotide 5 to 30 nucleotides in length wherein said oligonucleotide has at least 50% sequence identity to a reverse complement of an antisense of the EPO polynucleotide; thereby modulating function and/or expression of the EPO polynucleotide in patient cells or tissues in vivo or in vitro.
Another embodiment provides a method of modulating function and/or expression of an EPO polynucleotide in patient cells or tissues in vivo or in vitro comprising contacting said cells or tissues with an antisense oligonucleotide 5 to 30 nucleotides in length wherein said oligonucleotide has at least 50% sequence identity to an antisense oligonucleotide to an EPO antisense polynucleotide; thereby modulating function and/or expression of the EPO polynucleotide in patient cells or tissues in vivo or in vitro.
In a preferred embodiment, a composition comprises one or more antisense oligonucleotides which bind to sense and/or antisense EPO polynucleotides.
In another preferred embodiment, the oligonucleotides comprise one or more modified or substituted nucleotides.
In another preferred embodiment, the oligonucleotides comprise one or more modified bonds.
In yet another embodiment, the modified nucleotides comprise modified bases comprising phosphorothioate, methylphosphonate, peptide nucleic acids, 2′-O-methyl, fluoro- or carbon, methylene or other locked nucleic acid (LNA) molecules. Preferably, the modified nucleotides are locked nucleic acid molecules, including α-L-LNA.
In another preferred embodiment, the oligonucleotides are administered to a patient subcutaneously, intramuscularly, intravenously or intraperitoncally.
In another preferred embodiment, the oligonucleotides are administered in a pharmaceutical composition. A treatment regimen comprises administering the antisense compounds at least once to a patient, however, this treatment can be modified to include multiple doses over a period of time. The treatment can be combined with one or more other types of therapies.
In another preferred embodiment, the oligonucleotides are encapsulated in a liposome or attached to a carrier molecule (e.g. cholesterol, TAT peptide).
Another embodiment provides a method of modulating a function of and/or the expression of an Erythropoictin (EPO) polynucleotide in patient cells or tissues in vivo or in vitro comprising contacting said cells or tissues with at least one antisense oligonucleotide 5 to 30 nucleotides in length wherein said oligonucleotide has at least 50% sequence identity to an antisense oligonucleotide to the Erythropoictin (EPO) polynucleotide; thereby modulating a function of and/or the expression of the Erythropoietin (EPO) polynucleotide in patient cells or tissues in vivo or in vitro.
Another embodiment provides a method of modulating a function of and/or the expression of an Erythropoietin (EPO) polynucleotide in patient cells or tissues in vivo or in vitro comprising contacting said cells or tissues with at least one antisense oligonucleotide that targets a region of a natural antisense oligonucleotide of the Erythropoietin (EPO) polynucleotide; thereby modulating a function of and/or the expression of the Erythropoietin (EPO) polynucleotide in patient cells or tissues in vivo or in vitro.
In one embodiment, the expression and/or function of the Erythropoietin (EPO) is increased in vivo or in vitro with respect to a control.
In another embodiment, the at least one antisense oligonucleotide targets a natural antisense sequence of an Erythropoietin (EPO) polynucleotide.
In another embodiment, the at least one antisense oligonucleotide targets a nucleic acid sequence comprising coding and/or non-coding nucleic acid sequences of an Erythropoictin (EPO) polynucleotide.
In another embodiment, the at least one antisense oligonucleotide targets overlapping and/or non-overlapping sequences of an Erythropoietin (EPO) polynucleotide.
In one embodiment, the at least one antisense oligonucleotide comprises one or more modifications selected from: at least one modified sugar moiety, at least one modified internucleoside linkage, at least one modified nucleotide, and combinations thereof.
In a related embodiment, the one or more modifications comprise at least one modified sugar moiety selected from: a 2′-O-methoxyethyl modified sugar moiety, a 2′-methoxy modified sugar moiety, a 2′-O-alkyl modified sugar moiety, a bicyclic sugar moiety, and combinations thereof.
In another related embodiment, the one or more modifications comprise at least one modified internucleoside linkage selected from: a phosphorothioate, 2′-O-methoxyethyl (MOE), 2′-fluoro, alkylphosphonate, phosphorodithioate, alkylphosphonothioate, phosphoramidate, carbamate, carbonate, phosphate triester, acetamidate, carboxymethyl ester, and combinations thereof.
In another related embodiment, the one or more modifications comprise at least one modified nucleotide selected from: a peptide nucleic acid (PNA), a locked nucleic acid (LNA), an arabino-nucleic acid (FANA), analogues, derivatives and combinations thereof.
In another embodiment, the at least one oligonucleotide comprises at least one oligonucleotide sequence set forth as SEQ ID NOS: 4 to 6.
Another embodiment provides a method of modulating a function of and/or the expression of an Erythropoietin (EPO) gene in mammalian cells or tissues in vivo or in vitro comprising contacting said cells or tissues with at least one short interfering RNA (siRNA) oligonucleotide 5 to 30 nucleotides in length, said at least one siRNA oligonucleotide being specific for an antisense polynucleotide of an Erythropoietin (EPO) polynucleotide, wherein said at least one siRNA oligonucleotide has at least 50% sequence identity to a complementary sequence of at least about five consecutive nucleic acids of the antisense and/or sense nucleic acid molecule of the Erythropoietin (EPO) polynucleotide; and, modulating Erythropoietin (EPO) gene expression and/or function in mammalian cells or tissues in vivo or in vitro.
In an embodiment, said oligonucleotide has at least 80% sequence identity to a sequence of at least about five consecutive nucleic acids that is complementary to the antisense and/or sense nucleic acid molecule of the Erythropoietin (EPO) polynucleotide.
Another embodiment provides a method of modulating an Erythropoietin (EPO) gene expression and/or function in mammalian cells or tissues in vivo or in vitro comprising contacting said cells or tissues with at least one antisense oligonucleotide of about 5 to 30 nucleotides in length specific for noncoding and/or coding sequences of a sense and/or natural antisense strand of a polynucleotide encoding an Erythrooietin (EPO) molecule wherein the at least one antisense oligonucleotide has at least 50% sequence identity to at least one nucleic acid sequence set forth in SEQ ID NOS: 1 and 3; and, modulating Erythropoietin (EPO) gene expression and/or function in mammalian cells or tissues in vivo or in vitro.
Another embodiment of the invention provides a synthetic, modified oligonucleotide comprising at least one modification wherein the at least one modification is selected from: at least one modified sugar moiety; at least one modified internucleotide linkage; at least one modified nucleotide, and combinations thereof; wherein said oligonucleotide is an antisense compound which hybridizes to and modulates the expression of and/or a function of an Erythropoietin (EPO) gene in vivo or in vitro as compared to a normal control.
In an embodiment, the at least one modification comprises at least one internucleotide linkage selected from the group consisting of: phosphorothioate, alkylphosphonate, phosphorodithioate, alkylphosphonothioate, phosphoramidate, carbamate, carbonate, phosphate triester, acetamidate, carboxymethyl ester, and combinations thereof.
In another embodiment, the oligonucleotide comprises at least one phosphorothioate internucleotide linkage.
In a related embodiment, said oligonucleotide comprising a backbone of phosphorothioate internucleotide linkages.
In an embodiment, the oligonucleotide comprises at least one modified nucleotide selected from: a peptide nucleic acid, a locked nucleic acid (LNA), an analogue, a derivative, and combinations thereof.
In another embodiment, the oligonucleotide comprises a modified sugar moiety selected from: a 2′-O-methoxyethyl modified sugar moiety, a 2′-methoxy modified sugar moiety, a 2′-O-alkyl modified sugar moiety, a bicyclic sugar moiety, and combinations thereof.
In another embodiment, the oligonucleotide is of at least about 5 to 30 nucleotides in length and hybridizes to an antisense and/or sense strand of an Erythropoietin (EPO) polynucleotide, and wherein said antisense compound has at least about 20% sequence identity to a complementary sequence of at least about five consecutive nucleic acids of the antisense and/or sense coding and/or noncoding nucleic acid sequences of the Erythropoietin (EPO) polynucleotide.
In another embodiment, the oligonucleotide has at least about 80% sequence identity to a complementary sequence of at least about five consecutive nucleic acids of the antisense and/or sense coding and/or noncoding nucleic acid sequences of the Erythropoietin (EPO) polynucleotide.
In another embodiment, the oligonucleotide hybridizes to and modulates expression and/or function of at least one Erythropoietin (EPO) polynucleotide in vivo or in vitro, as compared to a normal control.
In a related embodiment, the oligonucleotide comprises one of the sequences set forth as SEQ ID NOS: 4 to 6.
One embodiment of the invention provides a composition comprising one or more oligonucleotides specific for one or more Erythropoietin (EPO) polynucleotides, said polynucleotides comprising antisense sequences, complementary sequences, alleles, homologs, isoforms, variants, derivatives, mutants, fragments, or combinations thereof.
In a related embodiment the oligonucleotides have at least about 40% sequence identity as compared to any one of the nucleotide, sequences set forth as SEQ ID NOS: 4 to 6.
In a certain embodiment, the oligonucleotides set forth as SEQ ID NOS: 4 to 6 comprise any of the nucleotide sequences set forth as SEQ ID NOS: 4 to 6.
In an embodiment, the oligonucleotides set forth as SEQ ID NOS: 4 to 6 comprise one or more modifications or nucleotide substitutions.
In another embodiment, the one or more modifications or nucleotide substitutions are selected from: phosphorothioate, methylphosphonate, peptide nucleic acid, locked nucleic acid (LNA) molecules, and combinations thereof.
An embodiment of the invention provides method of preventing or treating a disease or disorder associated with at least one Erythropoietin (EPO) polynucleotide and/or at least one encoded product thereof, comprising:
administering to a patient a therapeutically effective dose of at least one antisense oligonucleotide that binds to a natural antisense sequence of said at least one Erythropoictin (EPO) polynucleotide and modulates expression of said at least one Erythropoietin (EPO) polynucleotide; thereby preventing or treating the disease or disorder associated with the at least one Erythropoietin (EPO) polynucleotide and/or at least one encoded product thereof.
In embodiments, a disease or disorder associated with the at least one Erythropoietin (EPO) polynucleotide is selected from: a disease, disorder, or state of hematologic irregularity, a blood disorder characterized by low or defective red blood cell production, an anemia, sickle-cell anemia, beta-thalassemia, abnormal erythropoiesis, a pregnancy or menstrual disorder, early anemia of prematurity, renal insufficiency, Chronic Renal Failure, hypertension, a disease or disorder associated with surgery, a disease or disorder in a pediatric patient on dialysis, a disease or condition associated with insufficient hematocrit levels, AIDS, a disorder connected with chemotherapy treatments, cystic fibrosis, a cancer or tumor, an infectious disease, a venereal disease, an immunologically related disease and/or an autoimmune disease or disorder, a cardiovascular disease, e.g., stroke, hypotension, cardiac arrest, ischemia in particular ischemia-reperfusion injury, myocardial infarction such as acute myocardial infarctions, chronic heart failure, angina, cardiac hypertrophy, cardiopulmonary disease, heart-lung bypass, respiratory disease, kidney, a urinary/reproductive disease, an endocrine/metabolic abnormality, a gastrointestinal disease, a disease of the central nervous system (CNS) or peripheral nervous system which have primarily neurological or psychiatric symptoms, age-related loss of cognitive function, cerebral palsy, neurodegenerative disease, Alzheimer's disease, Parkinson's disease, Leigh's disease, dementia, memory loss, amyotrophic lateral sclerosis, alcoholism, mood disorder, anxiety disorder, attention deficit disorder, hyperactivity, autism, schizophrenia, depression, brain or spinal cord trauma or ischemia, Creutzfeld-Jakob disease, ophthalmic diseases, seizure disorder, multiple sclerosis, inflammation, radiation damage, macular degeneration, diabetic neuropathy, diabetic retinopathy, glaucoma, retinal ischemia, and retinal trauma, spinal cord injury, space flight, acute blood loss, aging and neoplastic disease states.
An embodiment of the invention provides a method of identifying and selecting at least one oligonucleotide for in vivo administration comprising selecting a target polynucleotide associated with a disease state; identifying oligonucleotides comprising at least five consecutive nucleotides which are complementary to, or in an antisense orientation to the selected target polynucleotide; and, measuring the thermal melting point of a hybrid of an antisense oligonucleotide and the target polynucleotide under stringent hybridization conditions; and selecting at least one oligonucleotide for in vivo administration based on the information obtained.
Other aspects are described infra.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph of real time PCR results showing the fold change in EPO mRNA after treatment of HepG2 cells with oligonucleotides introduced using Lipofectamine 2000, as compared to control. Real time PCR results show that the levels of the EPO mRNA are significantly increased 48 h after treatment with two of the siRNAs designed to epoas (epoas_1, P=0.02, and epoas _2, FIG. 1A). In the same samples the levels of epoas RNA were possibly decreased after treatment with siRNAs to epoas (FIG. 1B). Bars denoted as epoas_1, epoas_2, epoas_3 correspond to samples treated with SEQ ID NOS: 4, 5 and 6 respectively.
FIG. 2 shows SEQ ID NO: 1: Homo sapiens Erythropoietin (EPO), mRNA. (NCBI Accession No.:NM_000799.2) and SEQ ID NO: 2 shows the genomic sequence of EPO (exons are shown in capital letters, introns in small).
FIG. 3 shows SEQ ID NO: 3: Natural antisense sequence EPO-AS (NCBI Accession No: AW798641.1).
FIG. 4 shows the antisense, oligonucleotides SEQ ID NOS: 4 to 6. ‘r’ indicates RNA.
FIG. 5 shows the sense oligonucleotides SEQ ID NOS: 7 to 9, ‘r’ indicates RNA.
FIG. 6 shows the Forward primer (SEQ ID NO: 10), reverse primer (SEQ ID NO: 11) and the reporter sequence (SEQ ID NO: 12) of the Custom assays designed by Applied Biosystems Taqman Gene Expression Assay (Hs00171267_ml).



DETAILED DESCRIPTION
Several aspects of the invention are described below with reference to example applications for illustration. It should be understood that numerous specific details, relationships, and methods are set forth to provide a full understanding of the invention. One having ordinary skill in the relevant art, however, will readily recognize that the invention can be practiced without one or more of the specific details or with other methods. The present invention is not limited by the ordering of acts or events, as some acts may occur in different orders and/or concurrently with other acts or events. Furthermore, not all illustrated acts or events are required to implement a methodology in accordance with the present invention.
All genes, gene names, and gene products disclosed herein are intended to correspond to homologs from any species for which the compositions and methods disclosed herein are applicable. Thus, the terms include, but are not limited to genes and gene products from humans and mice. It is understood that when a gene or gene product from a particular species is disclosed, this disclosure is intended to be exemplary only, and is not to be interpreted as a limitation unless the context in which it appears clearly indicates. Thus, for example, for the genes disclosed herein, which in some embodiments relate to mammalian nucleic acid and amino acid sequences are intended to encompass homologous and/or orthologous genes and gene products from other animals including, but not limited to other mammals, fish, amphibians, reptiles, and birds. In preferred embodiments, the genes or nucleic acid sequences are human.
DEFINITIONS
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, to the extent that the terms “including,” “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description and/or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.”
The term “about” or “approximately” means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, “about” can mean within 1 or more than 1 standard deviation, per the practice in the art. Alternatively, “about” can mean a range of up to 20%, preferably up to 10%, more preferably up to 5%, and more preferably still up to 1% of a given value. Alternatively, particularly with respect to biological systems or processes, the term can mean within an order of magnitude, preferably within 5-fold, and more preferably within 2-fold, of a value. Where particular values are described in the application and claims, unless otherwise stated the term “about” meaning within an acceptable error range for the particular value should be assumed.
As used herein, the term “mRNA” means the presently known mRNA transcript(s) of a targeted gene, and any further transcripts which may be elucidated.
By “antisense oligonucleotides” or “antisense compound” is meant an RNA or DNA molecule that binds to another RNA or DNA (target RNA, DNA). For example, if it is an RNA oligonucleotide it binds to another RNA target by means of RNA-RNA interactions and alters the activity of the target RNA (Eguchi et al., (1991) Ann. Rev. Biochem. 60, 631-652). An antisense oligonucleotide can upregulate or downregulate expression and/or function of a particular polynucleotide. The definition is meant to include any foreign RNA or DNA molecule which is useful from a therapeutic, diagnostic, or other viewpoint. Such molecules include, for example, antisense RNA or DNA molecules, interference RNA (RNAi), micro RNA, decoy RNA molecules, siRNA, enzymatic RNA, therapeutic editing RNA and agonist and antagonist RNA, antisense oligomeric compounds, antisense oligonucleotides, external guide sequence (EGS) oligonucleotides, alternate splicers, primers, probes, and other oligomeric compounds that hybridize to at least a portion of the target nucleic acid. As such, these compounds may be introduced in the form of single-stranded, double-stranded, partially single-stranded, or circular oligomeric compounds.
In the context of this invention, the term “oligonucleotide” refers to an oligomer or polymer of ribonucleic acid (RNA) or deoxyribonucleic acid (DNA) or mimetics thereof. The term “oligonucleotide,” also includes linear or circular oligomers of natural and/or modified monomers or linkages, including deoxyribonucleosides, ribonucleosides, substituted and alpha-anomeric forms thereof, peptide nucleic acids (PNA), locked nucleic acids (LNA), phosphorothioate, methylphosphonate, and the like. Oligonucleotides are capable of specifically binding to a target polynucleotide by way of a regular pattern of monomer-to-monomer interactions, such as Watson-Crick type of base pairing, Hoögsteen or reverse Hoögsteen types of base pairing, or the like.
The oligonucleotide may be “chimeric,” that is, composed of different regions. In the context of this invention “chimeric” compounds are oligonucleotides, which contain two or more chemical regions, for example, DNA region(s), RNA region(s), PNA region(s) etc. Each chemical region is made up of at least one monomer unit, i.e., a nucleotide in the case of an oligonucleotide compound. These oligonucleotides typically comprise at least one region wherein the oligonucleotide is modified in order to exhibit one or more desired properties. The desired properties of the oligonucleotide include, but are not limited, for example, to increased resistance to nuclease degradation, increased cellular uptake, and/or increased binding affinity for the target nucleic acid. Different regions of the oligonucleotide may therefore have different properties. The chimeric oligonucleotides of the present invention can be formed as mixed structures of two or more oligonucleotides, modified oligonucleotides, oligonucleosides and/or oligonucleotide analogs as described above.
The oligonucleotide can be composed of regions that can be linked in “register,” that is, when the monomers are linked consecutively, as in native DNA, or linked via spacers. The spacers are intended to constitute a covalent “bridge” between the regions and have in preferred cases a length not exceeding about 100 carbon atoms. The spacers may carry different functionalities, for example, having positive or negative charge, carry special nucleic acid binding properties (intercalators, groove binders, toxins, fluorophors etc.), being lipophilic, inducing special secondary structures like, for example, alanine containing peptides that induce alpha-helices.
As used herein “EPO” and “Erythropoietin” are inclusive of all family members, mutants, alleles, fragments, species, coding and noncoding sequences, sense and antisense polynucleotide strands, etc.
As used herein, the words Erythropoietin, epoietin, EPO and hEPO (human erythropoietin), are used interchangeably in the present application.
As used herein, the term “oligonucleotide specific for” or “oligonucleotide which targets” refers to an oligonucleotide having a sequence (i) capable of forming a stable complex with a portion of the targeted gene, or (ii) capable of forming a stable duplex with a portion of a mRNA transcript of the targeted gene. Stability of the complexes and duplexes can be determined by theoretical calculations and/or in vitro assays. Exemplary assays for determining stability of hybridization complexes and duplexes are described in the Examples below.
As used herein, the term “target nucleic acid” encompasses DNA, RNA (comprising premRNA and mRNA) transcribed from such DNA, and also cDNA derived from such RNA, coding, noncoding sequences, sense or antisense polynucleotides. The specific hybridization of an oligomeric compound with its target nucleic acid interferes with the normal function of the nucleic acid. This modulation of function of a target nucleic acid by compounds, which specifically hybridize to it, is generally referred to as “antisense.” The functions of DNA to be interfered include, for example, replication and transcription. The functions of RNA to be interfered, include all vital functions such as, for example, translocation of the RNA to the site of protein translation, translation of protein from the RNA, splicing of the RNA to yield one or more mRNA species, and catalytic activity which may be engaged in or facilitated by the RNA. The overall effect of such interference with target nucleic acid function is modulation of the expression of an encoded product or oligonucleotides.
RNA interference “RNAi” is mediated by double stranded RNA (dsRNA) molecules that have sequence-specific homology to their “target” nucleic acid sequences (Caplen, N. J., et al. (2001) Proc. Natl. Acad. Sci. USA 98:9742-9747). In certain embodiments of the present invention, the mediators are 5-25 nucleotide “small interfering” RNA duplexes (siRNAs). The siRNAs are derived from the processing of dsRNA by an RNase enzyme known as Dicer (Bernstein, E., et al. (2001) Nature 409:363-366). siRNA duplex products are recruited into a multi-protein siRNA complex termed RISC (RNA Induced Silencing Complex). Without wishing to be bound by any particular theory, a RISC is then believed to be guided to a target nucleic acid (suitably mRNA), where the siRNA duplex interacts in a sequence-specific way to mediate cleavage in a catalytic fashion (Bernstein. E., et al. (2001) Nature 409:363-366; Boutla. A., et al. (2001) Curr. Biol. 11:1776-1780). Small interfering RNAs that can be used in accordance with the present invention can be synthesized and used according to procedures that are well known in the art and that will be familiar to the ordinarily skilled artisan. Small interfering RNAs for use in the methods of the present invention suitably comprise between about 1 to about 50 nucleotides (nt). In examples of non limiting embodiments, siRNAs can comprise about 5 to about 40 nt, about 5 to about 30 nt, about 10 to about 30 nt, about 15 to about 25 nt, or about 20-25 nucleotides.
Selection of appropriate oligonucleotides is facilitated by using computer programs that automatically align nucleic acid sequences and indicate regions of identity or homology. Such programs are used to compare nucleic acid sequences obtained, for example, by searching databases such as GenBank or by sequencing PCR products. Comparison of nucleic acid sequences from a range of species allows the selection of nucleic acid sequences that display an appropriate degree of identity between species. In the case of genes that have not been sequenced, Southern blots are performed to allow a determination of the degree of identity between genes in target species and other species. By performing Southern blots at varying degrees of stringency, as is well known in the art, it is possible to obtain an approximate measure of identity. These procedures allow the selection of oligonucleotides that exhibit a high degree of complementarity to target nucleic acid sequences in a subject to be controlled and a lower degree of complementarity to corresponding nucleic acid sequences in other species. One skilled in the art will realize that there is considerable latitude in selecting appropriate regions of genes for use in the present invention.
By “enzymatic RNA” is meant an RNA molecule with enzymatic activity (Cech, (1988) J. American. Med. Assoc. 260, 3030-3035). Enzymatic nucleic acids (ribozymes) act by first binding to a target RNA. Such binding occurs through the target binding portion of an enzymatic nucleic acid which is held in close proximity to an enzymatic portion of the molecule that acts to cleave the target RNA. Thus, the enzymatic nucleic acid first recognizes and then binds a target RNA through base pairing, and once bound to the correct site, acts enzymatically to cut the target RNA.
By “decoy RNA” is meant an RNA molecule that mimics the natural binding domain for a ligand. The decoy RNA therefore competes with natural binding target for the binding of a specific ligand. For example, it has been shown that over-expression of HIV trans-activation response (TAR) RNA can act as a “decoy” and efficiently binds HIV tat protein, thereby preventing it from binding to TAR sequences encoded in the HIV RNA (Sullenger et al. (1990) Cell, 63, 601-608). This is meant to be a specific example. Those in the art will recognize that this is but one example, and other embodiments can be readily generated using techniques generally known in the art.
As used herein, the term “monomers” typically indicates monomers linked by phosphodiester bonds or analogs thereof to form oligonucleotides ranging in size from a few monomeric units, e.g., from about 3-4, to about several hundreds of monomeric units. Analogs of phosphodiester linkages include: phosphorothioate, phosphorodithioate, methylphosphornates, phosphoroselenoate, phosphoramidate, and the like, as more fully described below.
The term “nucleotide” covers naturally occurring nucleotides as well as nonnaturally occurring nucleotides. It should be clear to the person skilled in the art that various nucleotides which previously have been considered “non-naturally occurring” have subsequently been found in nature. Thus, “nucleotides” includes not only the known purine and pyrimidine heterocycles-containing molecules, but also heterocyclic analogues and tautomers thereof. Illustrative examples of other types of nucleotides are molecules containing adenine, guanine, thymine, cytosine, uracil, purine, xanthine, diaminopurine, 8-oxo-N6-methyladenine, 7-deazaxanthine, 7-deazaguanine, N4,N4-ethanocytosin, N6,N6-ethano-2,6-diaminopurine, 5-methylcytosine, 5-(C3-C6)-alkynylcytosine, 5-fluorouracil, 5-bromouracil, pseudoisocytosine, 2-hydroxy-5-methyl-4-triazolopyridin, isocytosine, isoguanin, inosine and the “non-naturally occurring” nucleotides described in Benner et al., U.S. Pat. No. 5,432,272. The term “nucleotide” is intended to cover every and all of these examples as well as analogues and tautomers thereof. Especially interesting nucleotides are those containing adenine, guanine, thymine, cytosine, and uracil, which are considered as the naturally occurring nucleotides in relation to therapeutic and diagnostic application in humans. Nucleotides include the natural 2′-deoxy and 2′-hydroxyl sugars, e.g., as described in Kornberg and Baker, DNA Replication, 2nd Ed. (Freeman, San Francisco, 1992) as well as their analogs.
“Analogs” in reference to nucleotides includes synthetic nucleotides having modified base moieties and/or modified sugar moieties (see e.g., described generally by Scheit, Nucleotide Analogs, John Wiley, New York, 1980; Freier & Altmann, (1997) Nucl. Acid. Res., 25(22), 4429-4443, Toulmé, J. J., (2001) Nature Biotechnology 19:17-18; Manoharan M., (1999) Biochemica et Biophysica Acta 1489:117-139; Freier S. M., (1997) Nucleic Acid Research, 25:4429-4443, Uhlman, E., (2000) Drug Discovery & Development, 3: 203-213, Herdewin P., (2000) Antisense & Nucleic Acid Drug Dev., 10:297-310); 2′-O, 3′-C-linked [3.2.0] bicycloarabinonucleosides (see e.g. N. K Christiensen., et al, (1998) J. Am. Chem. Soc., 120: 5458-5463; Prakash T P, Bhat B. (2007) Curr Top Med Chem. 7(7):641-9; Cho E J, et al. (2009) Annual Review of Analytical Chemistry, 2, 241-264). Such analogs include synthetic nucleotides designed to enhance binding properties, e.g., duplex or triplex stability, specificity, or the like.
As used herein, “hybridization” means the pairing of substantially complementary strands of oligomeric compounds. One mechanism of pairing involves hydrogen bonding, which may be Watson-Crick, Hoögsteen or reversed Hoögsteen hydrogen bonding, between complementary nucleoside or nucleotide bases (nucleotides) of the strands of oligomeric compounds. For example, adenine and thymine are complementary nucleotides which pair through the formation of hydrogen bonds. Hybridization can occur under varying circumstances.
An antisense compound is “specifically hybridizable” when binding of the compound to the target nucleic acid interferes with the normal function of the target nucleic acid to cause a modulation of function and or activity, and there is a sufficient degree of complementarity to avoid non-specific binding of the antisense compound to non-target nucleic acid sequences under conditions in which specific binding is desired, i.e., under physiological conditions in the case of in vive assays or therapeutic treatment, and under conditions in which assays are performed in the case of in vitro assays.
As used herein, the phrase “stringent hybridization conditions” or “stringent conditions” refers to conditions under which a compound of the invention will hybridize to its target sequence, but to a minimal number of other sequences. Stringent conditions are sequence-dependent and will be different in different circumstances and in the context of this invention, “stringent conditions” under which oligomeric compounds hybridize to a target sequence are determined by the nature and composition of the oligomeric compounds and the assays in which they are being investigated. In general, stringent hybridization conditions comprise low concentrations (<0.15M) of salts with inorganic cations such as Na++ or K++ (i.e., low ionic strength), temperature higher than 20° C.-25° C. below the Tm of the oligomeric compound:target sequence complex, and the presence of denaturants such as formamide, dimethylformamide, dimethyl sulfoxide, or the detergent sodium dodecyl sulfate (SDS). For example, the hybridization rate decreases 1.1% for each 1% formamide. An example of a high stringency hybridization condition is 0.1× sodium chloride-sodium citrate buffer (SSC)/0.1% (w/v) SDS at 60° C. for 30 minutes.
“Complementary,” as used herein, refers to the capacity for precise pairing between two nucleotides on one or two oligomeric strands. For example, if a nucleobase at a certain position of an antisense compound is capable of hydrogen bonding with a nucleobase at a certain position of a target nucleic acid, said target nucleic acid being a DNA. RNA, or oligonucleotide molecule, then the position of hydrogen bonding between the oligonucleotide and the target nucleic acid is considered to be a complementary position. The oligomeric compound and the further DNA, RNA, or oligonucleotide molecule are complementary to each other when a sufficient number of complementary positions in each molecule are occupied by nucleotides which can hydrogen bond with each other. Thus, “specifically hybridizable” and “complementary” are terms which are used to indicate a sufficient degree of precise pairing or complementarity over a sufficient number of nucleotides such that stable and specific binding occurs between the oligomeric compound and a target nucleic acid.
It is understood in the art that the sequence of an oligomeric compound need not be 100% complementary to that of its target nucleic acid to be specifically hybridizable. Moreover, an oligonucleotide may hybridize over one or more segments such that intervening or adjacent segments are not involved in the hybridization event (e.g., a loop structure, mismatch or hairpin structure). The oligomeric compounds of the present invention comprise at least about 70%, or at least about 75%, or at least about 80%, or at least about 85%, or at least about 90%, or at least about 95%, or at least about 99% sequence complementarity to a target region within the target nucleic acid sequence to which they are targeted. For example, an antisense compound in which 18 of 20 nucleotides of the antisense compound are complementary to a target region, and would therefore specifically hybridize, would represent 90 percent complementarity. In this example, the remaining noncomplementary nucleotides may be clustered or interspersed with complementary nucleotides and need not be contiguous to each other or to complementary nucleotides. As such, an antisense compound which is 18 nucleotides in length having 4 (four) noncomplementary nucleotides which are flanked by two regions of complete complementarity with the target nucleic acid would have 77.8% overall complementarity with the target nucleic acid and would thus fall within the scope of the present invention. Percent complementarity of an antisense compound with a region of a target nucleic acid can be determined routinely using BLAST programs (basic local alignment search tools) and PowerBLAST programs known in the art (Altschul er al., (1990) J. Mol. Biol., 215, 403-410; Zhang and Madden, (1997) Genome Res., 7, 649-656). Percent homology, sequence identity or complementarity, can be determined by, for example, the Gap program (Wisconsin Sequence Analysis Package, Version 8 for Unix, Genetics Computer Group, University Research Park, Madison Wis.), using default settings, which uses the algorithm of Smith and Waterman (Adv. Appl. Math., (1981) 2, 482-489).
As used herein, the term “Thermal Melting Point (Tm)” refers to the temperature, under defined ionic strength, pH, and nucleic acid concentration, at which 50% of the oligonucleotides complementary to the target sequence hybridize to the target sequence at equilibrium. Typically, stringent conditions will be those in which the salt concentration is at least about 0.01 to 1.0 M Na ion concentration (or other salts) at pH 7.0 to 8.3 and the temperature is at least about 30° C. for short oligonucleotides (e.g., 10 to 50 nucleotide). Stringent conditions may also be achieved with the addition of destabilizing agents such as formamide.
As used herein, “modulation” means either an increase (stimulation) or a decrease (inhibition) in the expression of a gene.
The term “variant,” when used in the context of a polynucleotide sequence, may encompass a polynucleotide sequence related to a wild type gene. This definition may also include, for example, “allelic,” “splice,” “species,” or “polymorphic” variants. A splice variant may have significant identity to a reference molecule, but will generally have a greater or lesser number of polynucleotides due to alternate splicing of exons during mRNA processing. The corresponding polypeptide may possess additional functional domains or an absence of domains. Species variants are polynucleotide sequences that vary from one species to another. Of particular utility in the invention are variants of wild type gene products. Variants may result from at least one mutation in the nucleic acid sequence and may result in altered mRNAs or in polypeptides whose structure or function may or may not be altered. Any given natural or recombinant gene may have none, one, or many allelic forms. Common mutational changes that give rise to variants are generally ascribed to natural deletions, additions, or substitutions of nucleotides. Each of these types of changes may occur alone, or in combination with the others, one or more times in a given sequence.
The resulting polypeptides generally will have significant amino acid identity relative to each other. A polymorphic variant is a variation in the polynucleotide sequence of a particular gene between individuals of a given species. Polymorphic variants also may encompass “single nucleotide polymorphisms” (SNPs,) or single base mutations in which the polynucleotide sequence varies by one base. The presence of SNPs may be indicative of, for example, a certain population with a propensity for a disease state, that is susceptibility versus resistance.
Derivative polynucleotides include nucleic acids subjected to chemical modification, for example, replacement of hydrogen by an alkyl, acyl, or amino group. Derivatives, e.g., derivative oligonucleotides, may comprise non-naturally-occurring portions, such as altered sugar moieties or inter-sugar linkages. Exemplary among these are phosphorothioate and other sulfur containing species which are known in the art. Derivative nucleic acids may also contain labels, including radionucleotides, enzymes, fluorescent agents, chemiluminescent agents, chromogenic agents, substrates, cofactors, inhibitors, magnetic particles, and the like.
A “derivative” polypeptide or peptide is one that is modified, for example, by glycosylation, pegylation, phosphorylation, sulfation, reduction/alkylation, acylation, chemical coupling, or mild formalin treatment. A derivative may also be modified to contain a detectable label, either directly or indirectly, including, but not limited to, a radioisotope, fluorescent, and enzyme label.
As used herein, the term “animal” or “patient” is meant to include, for example, humans, sheep, elks, deer, mule deer, minks, mammals, monkeys, horses, cattle, pigs, goats, dogs, cats, rats, mice, birds, chicken, reptiles, fish, insects and arachnids.
“Mammal” covers warm blooded mammals that are typically under medical care (e.g., humans and domesticated animals). Examples include feline, canine, equine, bovine, and human, as well as just human.
“Treating” or “treatment” covers the treatment of a disease-state in a mammal, and includes: (a) preventing the disease-state from occurring in a mammal, in particular, when such mammal is predisposed to the disease-state but has not yet been diagnosed as having it; (b) inhibiting the disease-state, e.g., arresting it development; and/or (c) relieving the disease-state, e.g., causing regression of the disease state until a desired endpoint is reached. Treating also includes the amelioration of a symptom of a disease (e.g., lessen the pain or discomfort), wherein such amelioration may or may not be directly affecting the disease (e.g., cause, transmission, expression, etc.).
Polynucleotide and Oligonucleotide Compositions and Molecules
Targets: In one embodiment, the targets comprise nucleic acid sequences of Erythropoietin (EPO), including without limitation sense and/or antisense noncoding and/or coding sequences associated with EPO.
Erythropoietin (EPO) is a member of the hematopoietic growth factor family that acts as a hormone. EPO regulates the red blood cell (erythrocyte) production (erythropoiesis) and maintains the body's red blood cell mass at an optimum level. EPO production is stimulated by reduced oxygen content in the renal arterial circulation, mediated by a transcription factor that is oxygen-sensitive. EPO is produced primarily by cells of the peritubular capillary endothelium of the kidney. Secreted EPO binds to EPO receptors on the surface of bone marrow erythroid precursors, and results in their rapid replication and maturation to functional red blood cells. This stimulation results in a rapid rise in erythrocyte counts and a consequent rise in hematocrit (% of red blood cells in blood) (D'Andrea et al. (1989) Cell 57: 277-285; Lodish et al. (1995) Cold Spring Harb Symp Quant Biol 60: 93-104).
Erythropoictin stimulates the bone marrow to produce more red blood cells. The resultant rise in red blood cells increases the oxygen-carrying capacity of the blood. As the prime regulator of red blood cell production, erythropoietin's major functions are to: promote the development of red blood cells; initiate the synthesis of hemoglobin, the molecule within red blood cells that transports oxygen.
EPO stimulates mitotic division and the differentiation of erythrocyte precursor cells and thus ensures the production of erythrocytes. It is produced in kidney when hypoxic conditions prevail. During EPO-induced differentiation of erythrocyte precursor cells, there is induction of globulin synthesis and increase in synthesis of the heme complex and in the number of ferritin receptors. This makes it possible for the cell to take on more ion and synthesize functional hemoglobin. Hemoglobin in mature erythrocytes binds oxygen. Thus, the erythrocytes and the hemoglobin contained in them play a key part in supplying the body with oxygen. The complex processes which have been described are initiated by the interaction of EPO with an appropriate receptor on the cell surface of erythrocyte precursor cells.
EPO is present in very low concentrations in the plasma when the body is in a healthy state wherein tissues receive sufficient oxygenation from the existing number of erythrocytes. This normal low concentration is enough to stimulate replacement of red blood cells which are lost normally through aging.
The amount of EPO in the circulation is increased under conditions of hypoxia when the oxygen transport by blood cells in the circulation is reduced. Hypoxia may be caused by loss of large amounts of blood through hemorrhage, destruction of red blood cells by over exposure to radiation, reduction in oxygen intake due to high altitudes or prolonged unconsciousness, or various forms of anemia. In response to tissues undergoing hypoxic stress, EPO will increase red blood cell production by stimulation of proliferation of erythroid progenitor cells. When the number of red blood cells in the circulation is greater than needed for normal tissue oxygen requirements, EPO in circulation is decreased.
Because EPO is essential in the process of red blood cell formation, the hormone has potentially useful applications in both diagnosis and the treatment of blood disorders characterized by low or defective blood cell production. Exemplary erythropoictin-mediated diseases and disorders which can be treated with cell/tissues regenerated from stem cells obtained using the antisense compounds comprise diseases or conditions which utilize the tissue protective activities of an EPO polypeptide for protection against an injury or restoration of function following the injury to responsive mammalian cells, tissues or organs. Examples of such diseases or conditions include, but are not limited to disease states, disorders, and states of hematologic irregularity, blood disorders characterized by low or defective red blood cell production, anemia, sickle-cell anemia, beta-thalassemia, abnormal erythropoiesis, pregnancy and menstrual disorders, early anemia of prematurity, renal insufficiency, Chronic Renal Failure, hypertension, a disease or disorder associated with surgery, a disease or disorder in a pediatric patient on dialysis, diseases or conditions associated with insufficient hematocrit levels, AIDS, disorders connected with chemotherapy treatments, cystic fibrosis, cancers and tumors, infectious diseases, venereal diseases, immunologically related diseases and/or autoimmune diseases and disorders, cardiovascular diseases such as stroke, hypotension, cardiac arrest, ischemia in particular ischemia-reperfusion injury, myocardial infarction such as acute myocardial infarctions, chronic heart failure, angina, cardiac hypertrophy, cardiopulmonary diseases, heart-lung bypass, respiratory diseases, kidney, urinary and reproductive diseases, endocrine and metabolic abnormalities, gastrointestinal diseases, diseases of the central nervous system (CNS) or peripheral nervous system which have primarily neurological or psychiatric symptoms, age-related loss of cognitive function, cerebral palsy, neurodegenerative disease. Alzheimer's disease, Parkinson's disease, Leigh's disease, dementia, memory loss, amyotrophic lateral sclerosis, alcoholism, mood disorder, anxiety disorder, attention deficit disorder, hyperactivity, autism, schizophrenia, depression, brain or spinal cord trauma or ischemia. Creutzfeld-Jakob disease, ophthalmic diseases, seizure disorder, multiple sclerosis, inflammation, radiation damage, macular degeneration, diabetic neuropathy, diabetic retinopathy, glaucoma, retinal ischemia, and retinal trauma, spinal cord injury, space flight, acute blood loss, aging and various neoplastic disease states.
In embodiments, the methods and compositions of the invention are used to modulate any function of erythropoietin. Assays for determining modulation of erythropoietin functions are known in the art and have been described in the literature. For example, U.S. Pat. No. 5,688,679, “Human erythropoietin gene; high level expression in stably transfected mammalian cells” incorporated herein by reference, reported use of an in vitro assay for erythropoietin biological activity that is based on the formation of erythroid colonies (from CFU-E; erythroid colony-forming cells) in cultures of mouse bone marrow cells in plasma clot (Blood Cells 4:89-103, 1978). The sensitivity of this assay was reportedly about 5 milliunits/ml. The erythropoietin used as the standard for the assay was a partially purified preparation from plasma from anemic sheep. Supernatants were assayed from passaged cell lines grown for 24 hours in fresh medium without methotrexate. The supernatant was diluted 1:200 with medium, and amounts between 1 and 10 microliters were added per milliliter of assay culture containing 2×10 5 marrow cells, 10% bovine citrated plasma, 20% fetal calf serum, 1% bovine serum albumin, and 1.6% beef embryo extract (Gibco). After incubation for 36 to 48 hours the plasma clots were fixed on microscope slides, stained with benzidine for hemoglobin, and erythroid colonies were enumerated.
U.S. Pat. No. 5,688,679 also reported the use of supernatants from selected cell lines to assay for immunologically reactive erythropoietin by competitive radioimmunoassay using a polyvalent anti-human-erythropoietin rabbit anti-serum (J. Cell. Physiol. 118:87-96, 1984), incorporated herein by reference. Erythropoietin can also be detected using other immunological methods, e.g., Western blot and immunofluorescence.
Further, the same patent described assaying erythropoictin secreted into the cell supernatant for proliferative effects on other marrow progenitor cells. Erythropoictin can be assayed for its effect on a variety of progenitors from mouse and human marrow including erythroid colony-forming cells (CFU-E), erythroid burst-forming cells (BFU-E), granulocyte-macrophage precursors (CFU-GM), and mixed-cell colony-forming cells (CFU-Mix) (J. Cell. Physiol. Suppl. 1:79-85, 1982; J. Cell. Physiol. 118:87-96, 1984), incorporated herein by reference.
Erythropoietin also has been reported to affect cell types other than those of the red blood cell lineage. For example, Lifshitz, et al., 2009, “Non-erythroid activities of erythropoietin: Functional effects on murine dendritic cells,” Mol Immunol. 46(4):713-21, incorporated herein by reference, reported in-vivo experiments in EPO-injected mice and in transgenic mice over-expressing human EPO showing an increased splenic DC population with a higher cell surface expression of CD80 and CD86. Prutchi, et al., 2008, “Erythropoietin effects on dendritic cells: potential mediators in its function as an immunomodulator?” Exp Hematol. 36(12):1682-90, reported that when applied in vitro. EPO increased the percentage of peripheral blood DCs and monocyte-derived DCs (MoDCs) expressing the costimulatory molecules CD80 and CD86.
In a preferred embodiment, the oligonucleotides are specific for polynucleotides of EPO, which includes, without limitation, noncoding regions. The EPO targets comprise variants of EPO; mutants of EPO, including SNPs; noncoding sequences of EPO; alleles, fragments and the like. Preferably the oligonucleotide is an antisense RNA molecule.
In accordance with embodiments of the invention, the target nucleic acid molecule is not limited to EPO polynucleotides alone but extends to any of the isoforms, receptors, homologs, non-coding regions and the like of EPO.
In another preferred embodiment, an oligonucleotide targets a natural antisense sequence (natural antisense to the coding and non-coding regions) of EPO targets, including, without limitation, variants, alleles, homologs, mutants, derivatives, fragments and complementary sequences thereto. Preferably the oligonucleotide is an antisense RNA or DNA molecule.
In another preferred embodiment, the oligomeric compounds of the present invention also include variants in which a different base is present at one or more of the nucleotide positions in the compound. For example, if the first nucleotide is an adenine, variants may be produced which contain thymidine, guanosine, cytidine or other natural or unnatural nucleotides at this position. This may be done at any of the positions of the antisense compound. These compounds are then tested using the methods described herein to determine their ability to inhibit expression of a target nucleic acid.
In some embodiments, homology, sequence identity or complementarity, between the antisense compound and target is from about 50% to about 60%. In some embodiments, homology, sequence identity or complementarity, is from about 60% to about 70%. In some embodiments, homology, sequence identity or complementarity, is from about 70% to about 80%. In some embodiments, homology, sequence identity or complementarity, is from about 80% to about 90%. In some embodiments, homology, sequence identity or complementarity, is about 90%, about 92%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99% or about 100%.
An antisense compound is specifically hybridizable when binding of the compound to the target nucleic acid interferes with the normal function of the target nucleic acid to cause a loss of activity, and there is a sufficient degree of complementarity to avoid non-specific binding of the antisense compound to non-target nucleic acid sequences under conditions in which specific binding is desired. Such conditions include, i.e., physiological conditions in the case of in vivo assays or therapeutic treatment, and conditions in which assays are performed in the case of in vitro assays.
An antisense compound, whether DNA, RNA, chimeric, substituted etc. is specifically hybridizable when binding of the compound to the target DNA or RNA molecule interferes with the normal function of the target DNA or RNA to cause a loss of utility, and there is a sufficient degree of complementarily to avoid non-specific binding of the antisense compound to non-target sequences under conditions in which specific binding is desired, i.e., under physiological conditions in the case of in vivo assays or therapeutic treatment, and in the case of in vitro assays, under conditions in which the assays are performed.
In another preferred embodiment, targeting of EPO including without limitation, antisense sequences which are identified and expanded, using for example, PCR, hybridization etc., one or more of the sequences set forth as SEQ ID NO:3, and the like, modulate the expression or function of EPO. In one embodiment, expression or function is up-regulated as compared to control. In another preferred embodiment, expression or function is down-regulated as compared to a control.
In another preferred embodiment, oligonucleotides comprise nucleic acid sequences set forth as SEQ ID NOS: 4 to 6 including antisense sequences which are identified and expanded, using for example, PCR, hybridization etc. These oligonucleotides can comprise one or more modified nucleotides, shorter or longer fragments, modified bonds and the like. Examples of modified bonds or internucleotide linkages comprise phosphorothioate, phosphorodithioate or the like. In another preferred embodiment, the nucleotides comprise a phosphorus derivative. The phosphorous derivative (or modified phosphate group) which may be attached to the sugar or sugar analog moiety in the modified oligonucleotides of the present invention may be a monophosphate, diphosphate, triphosphate, alkylphosphate, alkanephosphate, phosphorothioate and the like. The preparation of the above-noted phosphate analogs, and their incorporation into nucleotides, modified nucleotides and oliognucleotides, per se, is also know and need not be described here.
The specificity and sensitivity of antisense is also harnessed by those of skill in the art for therapeutic uses. Antisense oligonucleotides have been employed as therapeutic moieties in the treatment of disease states in animals and man. Antisense oligonucleotides have been safely and effectively administered to humans and numerous clinical trials are presently underway. It is thus established that oligonucleotides can be useful therapeutic modalities that can be configured to be useful in treatment regimes for treatment of cells, tissues and animals, especially humans.
In embodiments of the present invention oligomeric antisense compounds, particularly oligonucleotides, bind to target nucleic acid molecules and modulate the expression and/or function of molecules encoded by a target gene. The functions of DNA to be interfered with comprise, for example, replication and transcription. The functions of RNA to be interfered with comprise all vital functions such as, for example, translocation of the RNA to the site of protein translation, translation of protein from the RNA, splicing of the RNA to yield one or more mRNA species, and catalytic activity which may be engaged in or facilitated by the RNA. The functions may be up-regulated or inhibited depending on the functions desired.
The antisense compounds, include, antisense oligomeric compounds, antisense oligonucleotides, external guide sequence (EGS) oligonucleotides, alternate splicers, primers, probes, and other oligomeric compounds that hybridize to at least a portion of the target nucleic acid. As such, these compounds may be introduced in the form of single-stranded, double-stranded, partially single-stranded, or circular oligomeric compounds.
Targeting an antisense compound to a particular nucleic acid molecule, in the context of this invention, can be a multistep process. The process usually begins with the identification of a target nucleic acid whose function is to be modulated. This target nucleic acid may be, for example, a cellular gene (or mRNA transcribed from the gene) whose expression is associated with a particular disorder or disease state, or a nucleic acid molecule from an infectious agent. In the present invention, the target nucleic acid encodes Erythropoietin (EPO).
The targeting process usually also includes determination of at least one target region, segment, or site within the target nucleic acid for the antisense interaction to occur such that the desired effect, e.g., modulation of expression, will result. Within the context of the present invention, the term “region” is defined as a portion of the target nucleic acid having at least one identifiable structure, function, or characteristic. Within regions of target nucleic acids are segments. “Segments” are defined as smaller or sub-portions of regions within a target nucleic acid. “Sites,” as used in the present invention, are defined as positions within a target nucleic acid.
In a preferred embodiment, the antisense oligonucleotides bind to the natural antisense sequences of Erythropoietin (EPO) and modulate the expression and/or function of Erythropoietin (EPO) (SEQ ID NO: 1). Examples of antisense sequences include SEQ ID NOS: 4 to 6.
In another preferred embodiment, the antisense oligonucleotides bind to one or more segments of Erythropoietin (EPO) polynucleotides and modulate the expression and/or function of Erythropoietin (EPO). The segments comprise at least five consecutive nucleotides of the Erythropoietin (EPO) sense or antisense polynucleotides.
In another preferred embodiment, the antisense oligonucleotides are specific for natural antisense sequences of Erythropoietin (EPO) wherein binding of the oligonucleotides to the natural antisense sequences of Erythropoietin (EPO) modulate expression and/or function of Erythropoietin (EPO).
In another preferred embodiment, oligonucleotides compounds comprise sequences forth as SEQ ID NOS: 4 to 6, antisense sequences which are identified and expanded, using for example, PCR, hybridization etc. These oligonucleotides can comprise one or more modified nucleotides, shorter or longer fragments, modified bonds and the like. Examples of modified bonds or internucleotide linkages comprise phosphorothioate, phosphorodithioate or the like. In another preferred embodiment, the nucleotides comprise a phosphorus derivative. The phosphorus derivative (or modified phosphate group) which may be attached to the sugar or sugar anaolog moiety in the modified oligonucleotides of the present invention may be a monophosphate, diphosphate, triphosphate, alkylphosphate, alkanephosphate, phosphorothioate and the like. The preparation of the above-noted phosphate analogs, and their incorporation into nucleotides, modified nucleotides and oligonucleotides per se is also known and need not be described here.
Since, as is known in the art, the translation initiation codon is typically 5′-AUG (in transcribed mRNA molecules; 5′-ATG in the corresponding DNA molecule), the translation initiation codon is also referred to as the “AUG codon,” the “start codon” or the “AUG start codon.” A minority of genes has a translation initiation codon having the RNA sequence 5′-GUG, 5′-UUG or 5′-CUG; and 5′-AUA, 5′-ACG and 5′-CUG have been shown to function in vivo. Thus, the terms “translation initiation codon” and “start codon” can encompass many codon sequences, even though the initiator amino acid in each instance is typically methionine (in eukaryotes) or formylmethionine (in prokaryotes). Eukaryotic and prokaryotic genes may have two or more alternative start codons, any one of which may be preferentially utilized for translation initiation in a particular cell type or tissue, or under a particular set of conditions. In the context of the invention. “start codon” and “translation initiation codon” refer to the codon or codons that are used in vivo to initiate translation of an mRNA transcribed from a gene encoding Erythropoietin (EPO), regardless of the sequence(s) of such codons. A translation termination codon (or “stop codon”) of a gene may have one of three sequences, i.e., 5′-UAA, 5′-UAG and 5′-UGA (the corresponding DNA sequences are 5′-TAA, 5′-TAG and 5′-TGA, respectively).
The terms “start codon region” and “translation initiation codon region” refer to a portion of such an mRNA or gene that encompasses from about 25 to about 50 contiguous nucleotides in either direction (i.e., 5′ or 3) from a translation initiation codon. Similarly, the terms “stop codon region” and “translation termination codon region” refer to a portion of such an mRNA or gene that encompasses from about 25 to about 50 contiguous nucleotides in either direction (i.e., 5′ or 3′) from a translation termination codon. Consequently, the “start codon region” (or “translation initiation codon region”) and the “stop codon region” (or “translation termination codon region”) are all regions that may be targeted effectively with the antisense compounds of the present invention.
The open reading frame (ORF) or “coding region.” which is known in the art to refer to the region between the translation initiation codon and the translation termination codon, is also a region which may be targeted effectively. Within the context of the present invention, a targeted region is the intragenic region encompassing the translation initiation or termination codon of the open reading frame (ORF) of a gene.
Another target region includes the 5′ untranslated region (5′UTR), known in the art to refer to the portion of an mRNA in the 5′ direction from the translation initiation codon, and thus including nucleotides between the 5′ cap site and the translation initiation codon of an mRNA (or corresponding nucleotides on the gene). Still another target region includes the 3′ untranslated region (3′UTR), known in the art to refer to the portion of an mRNA in the 3′ direction from the translation termination codon, and thus including nucleotides between the translation termination codon and 3′ end of an mRNA (or corresponding nucleotides on the gene). The 5′ cap site of an mRNA comprises an N7-methylated guanosine residue joined to the 5′-most residue of the mRNA via a 5′-5′ triphosphate linkage. The 5′ cap region of an mRNA is considered to include the 5′ cap structure itself as well as the first 50 nucleotides adjacent to the cap site. Another target region for this invention is the 5′ cap region.
Although some eukaryotic mRNA transcripts are directly translated, many contain one or more regions, known as “introns,” which are excised from a transcript before it is translated. The remaining (and therefore translated) regions are known as “exons” and are spliced together to form a continuous mRNA sequence. In one embodiment, targeting splice sites, i.e., intron-exon junctions or exon-intron junctions, is particularly useful in situations where aberrant splicing is implicated in disease, or where an overproduction of a particular splice product is implicated in disease. An aberrant fusion junction due to rearrangement or deletion is another embodiment of a target site. mRNA transcripts produced via the process of splicing of two (or more) mRNAs from different gene sources are known as “fusion transcripts.” Introns can be effectively targeted using antisense compounds targeted to, for example, DNA or pre-mRNA.
In another preferred embodiment, the antisense oligonucleotides bind to coding and/or non-coding regions of a target polynucleotide and modulate the expression and/or function of the target molecule.
In another preferred embodiment, the antisense oligonucleotides bind to natural antisense polynucleotides and modulate the expression and/or function of the target molecule.
In another preferred embodiment, the antisense oligonucleotides bind to sense polynucleotides and modulate the expression and/or function of the target molecule.
Alternative RNA transcripts can be produced from the same genomic region of DNA. These alternative transcripts are generally known as “variants.” More specifically, “pre-mRNA variants” are transcripts produced from the same genomic DNA that differ from other transcripts produced from the same genomic DNA in either their start or stop position and contain both intronic and exonic sequence.
Upon excision of one or more exon or intron regions, or portions thereof during splicing, pre-mRNA variants produce smaller “mRNA variants.” Consequently, mRNA variants are processed pre-mRNA variants and each unique pre-mRNA variant must always produce a unique mRNA variant as a result of splicing. These mRNA variants are also known as “alternative splice variants.” If no splicing of the pre-mRNA variant occurs then the pre-mRNA variant is identical to the mRNA variant.
Variants can be produced through the use of alternative signals to start or stop transcription. Pre-mRNAs and mRNAs can possess more than one start codon or stop codon. Variants that originate from a pre-mRNA or mRNA that use alternative start codons are known as “alternative start variants” of that pre-mRNA or mRNA. Those transcripts that use an alternative stop codon are known as “alternative stop variants” of that pre-mRNA or mRNA. One specific type of alternative stop variant is the “polyA variant” in which the multiple transcripts produced result from the alternative selection of one of the “polyA stop signals” by the transcription machinery, thereby producing transcripts that terminate at unique polyA sites. Within the context of the invention, the types of variants described herein are also embodiments of target nucleic acids.
The locations on the target nucleic acid to which the antisense compounds hybridize are defined as at least a 5-nucleotide long portion of a target region to which an active antisense compound is targeted.
While the specific sequences of certain exemplary target segments are set forth herein, one of skill in the art will recognize that these serve to illustrate and describe particular embodiments within the scope of the present invention. Additional target segments are readily identifiable by one having ordinary skill in the art in view of this disclosure.
Target segments 5-100 nucleotides in length comprising a stretch of at least five (5) consecutive nucleotides selected from within the illustrative preferred target segments are considered to be suitable for targeting as well.
Target segments can include DNA or RNA sequences that comprise at least the 5 consecutive nucleotides from the 5′-terminus of one of the illustrative preferred target segments (the remaining nucleotides being a consecutive stretch of the same DNA or RNA beginning immediately upstream of the 5′-terminus of the target segment and continuing until the DNA or RNA contains about 5 to about 100 nucleotides). Similarly preferred target segments are represented by DNA or RNA sequences that comprise at least the 5 consecutive nucleotides from the 3′-terminus of one of the illustrative preferred target segments (the remaining nucleotides being a consecutive stretch of the same DNA or RNA beginning immediately downstream of the 3′-terminus of the target segment and continuing until the DNA or RNA contains about 5 to about 100 nucleotides). One having skill in the art armed with the target segments illustrated herein will be able, without undue experimentation, to identify further preferred target segments.
Once one or more target regions, segments or sites have been identified, antisense compounds are chosen which are sufficiently complementary to the target, i.e., hybridize sufficiently well and with sufficient specificity, to give the desired effect.
In embodiments of the invention the oligonucleotides bind to an antisense strand of a particular target. The oligonucleotides are at least 5 nucleotides in length and can be synthesized so each oligonucleotide targets overlapping sequences such that oligonucleotides are synthesized to cover the entire length of the target polynucleotide. The targets also include coding as well as non coding regions.
In one embodiment, it is preferred to target specific nucleic acids by antisense oligonucleotides. Targeting an antisense compound to a particular nucleic acid, is a multistep process. The process usually begins with the identification of a nucleic acid sequence whose function is to be modulated. This may be, for example, a cellular gene (or mRNA transcribed from the gene) whose expression is associated with a particular disorder or disease state, or a non coding polynucleotide such as for example, non coding RNA (ncRNA).
RNAs can be classified into (1) messenger RNAs (mRNAs), which are translated into proteins, and (2) non-protein-coding RNAs (ncRNAs). ncRNAs comprise microRNAs, antisense transcripts and other Transcriptional Units (TU) containing a high density of stop codons and lacking any extensive “Open Reading Frame.” Many ncRNAs appear to start from initiation sites in 3′ untranslated regions (3′UTRs) of protein-coding loci. ncRNAs are often rare and at least half of the ncRNAs that have been sequenced by the FANTOM consortium seem not to be polyadenylated. Most researchers have for obvious reasons focused on polyadenylated mRNAs that are processed and exported to the cytoplasm. Recently, it was shown that the set of non-polyadenylated nuclear RNAs may be very large, and that many such transcripts arise from so-called intergenic regions (Cheng, J. et al. (2005) Science 308 (5725), 1149-1154; Kapranov, P. et al. (2005). Genome Res 15 (7), 987-997). The mechanism by which ncRNAs may regulate gene expression is by base pairing with target transcripts. The RNAs that function by base pairing can be grouped into (1) cis encoded RNAs that are encoded at the same genetic location, but on the opposite strand to the RNAs they act upon and therefore display perfect complementarity to their target, and (2) trans-encoded RNAs that are encoded at a chromosomal location distinct from the RNAs they act upon and generally do not exhibit perfect base-pairing potential with their targets.
Without wishing to be bound by theory, perturbation of an antisense polynucleotide by the antisense oligonucleotides described herein can alter the expression of the corresponding sense messenger RNAs. However, this regulation can either be discordant (antisense knockdown results in messenger RNA elevation) or concordant (antisense knockdown results in concomitant messenger RNA reduction). In these cases, antisense oligonucleotides can be targeted to overlapping or non-overlapping parts of the antisense transcript resulting in its knockdown or sequestration. Coding as well as non-coding antisense can be targeted in an identical manner and that either category is capable of regulating the corresponding sense transcripts—either in a concordant or disconcordant manner. The strategies that are employed in identifying new oligonucleotides for use against a target can be based on the knockdown of antisense RNA transcripts by antisense oligonucleotides or any other means of modulating the desired target.
Strategy 1: In the case of discordant regulation, knocking down the antisense transcript elevates the expression of the conventional (sense) gene. Should that latter gene encode for a known or putative drug target, then knockdown of its antisense counterpart could conceivably mimic the action of a receptor agonist or an enzyme stimulant.
Strategy 2: In the case of concordant regulation, one could concomitantly knock down both antisense and sense transcripts and thereby achieve synergistic reduction of the conventional (sense) gene expression. If, for example, an antisense oligonucleotide is used to achieve knockdown, then this strategy can be used to apply one antisense oligonucleotide targeted to the sense transcript and another antisense oligonucleotide to the corresponding antisense transcript, or a single energetically symmetric antisense oligonucleotide that simultaneously targets overlapping sense and antisense transcripts.
According to the present invention, antisense compounds include antisense oligonucleotides, ribozymes, external guide sequence (EGS) oligonucleotides, siRNA compounds, single- or double-stranded RNA interference (RNAi) compounds such as siRNA compounds, and other oligomeric compounds which hybridize to at least a portion of the target nucleic acid and modulate its function. As such, they may be DNA, RNA, DNA-like, RNA-like, or mixtures thereof, or may be mimetics of one or more of these. These compounds may be single-stranded, doublestranded, circular or hairpin oligomeric compounds and may contain structural elements such as internal or terminal bulges, mismatches or loops. Antisense compounds are routinely prepared linearly but can be joined or otherwise prepared to be circular and/or branched. Antisense compounds can include constructs such as, for example, two strands hybridized to form a wholly or partially double-stranded compound or a single strand with sufficient self-complementarity to allow for hybridization and formation of a fully or partially double-stranded compound. The two strands can be linked internally leaving free 3′ or 5′ termini or can be linked to form a continuous hairpin structure or loop. The hairpin structure may contain an overhang on either the 5′ or 3′ terminus producing an extension of single stranded character. The double stranded compounds optionally can include overhangs on the ends. Further modifications can include conjugate groups attached to one of the termini, selected nucleotide positions, sugar positions or to one of the internucleoside linkages. Alternatively, the two strands can be linked via a non-nucleic acid moiety or linker group. When formed from only one strand, dsRNA can take the form of a self-complementary hairpin-type molecule that doubles back on itself to form a duplex. Thus, the dsRNAs can be fully or partially double stranded. Specific modulation of gene expression can be achieved by stable expression of dsRNA hairpins in transgenic cell lines, however, in some embodiments, the gene expression or function is up regulated. When formed from two strands, or a single strand that takes the form of a self-complementary hairpin-type molecule doubled back on itself to form a duplex, the two strands (or duplex-forming regions of a single strand) are complementary RNA strands that base pair in Watson-Crick fashion.
Once introduced to a system, the compounds of the invention may elicit the action of one or more enzymes or structural proteins to effect cleavage or other modification of the target nucleic acid or may work via occupancy-based mechanisms. In general, nucleic acids (including oligonucleotides) may be described as “DNA-like” (i.e., generally having one or more 2′-deoxy sugars and, generally, T rather than U bases) or “RNA-like” (i.e., generally having one or more 2′-hydroxyl or 2′-modified sugars and, generally U rather than T bases). Nucleic acid helices can adopt more than one type of structure, most commonly the A- and B-forms. It is believed that, in general, oligonucleotides which have B-form-like structure are “DNA-like” and those which have A-formlike structure are “RNA-like.” In some (chimeric) embodiments, an antisense compound may contain both A- and B-form regions.
In another preferred embodiment, the desired oligonucleotides or antisense compounds, comprise at least one of: antisense RNA, antisense DNA, chimeric antisense oligonucleotides, antisense oligonucleotides comprising modified linkages, interference RNA (RNAi), short interfering RNA (siRNA): a micro, interfering RNA (miRNA): a small, temporal RNA (stRNA); or a short, hairpin RNA (shRNA); small RNA-induced gene activation (RNAa); small activating RNAs (saRNAs), or combinations thereof.
dsRNA can also activate gene expression, a mechanism that has been termed “small RNA-induced gene activation” or RNAa. dsRNAs targeting gene promoters induce potent transcriptional activation of associated genes. RNAa was demonstrated in human cells using synthetic dsRNAs, termed “small activating RNAs” (saRNAs). It is currently not known whether RNAa is conserved in other organisms.
Small double-stranded RNA (dsRNA), such as small interfering RNA (siRNA) and microRNA (miRNA), have been found to be the trigger of an evolutionary conserved mechanism known as RNA interference (RNAi). RNAi invariably leads to gene silencing via remodeling chromatin to thereby suppress transcription, degrading complementary mRNA, or blocking protein translation. However, in instances described in detail in the examples section which follows, oligonucleotides are shown to increase the expression and/or function of the Erythropoictin (EPO) polynucleotides and encoded products thereof. dsRNAs may also act as small activating RNAs (saRNA). Without wishing to be bound by theory, by targeting sequences in gene promoters, saRNAs would induce target gene expression in a phenomenon referred to as dsRNA-induced transcriptional activation (RNAa).
In a further embodiment, the “preferred target segments” identified herein may be employed in a screen for additional compounds that modulate the expression of Erythropoietin (EPO) polynucleotides. “Modulators” are those compounds that decrease or increase the expression of a nucleic acid molecule encoding Erythropoietin (EPO) and which comprise at least a 5-nucleotide portion that is complementary to a preferred target segment. The screening method comprises the steps of contacting a preferred target segment of a nucleic acid molecule encoding sense or natural antisense polynucleotides of Erythropoietin
(EPO) with one or more candidate modulators, and selecting for one or more candidate modulators which decrease or increase the expression of a nucleic acid molecule encoding Erythropoietin (EPO) polynucleotides, e.g. SEQ ID NOS: 4 to 6. Once it is shown that the candidate modulator or modulators are capable of modulating (e.g, either decreasing or increasing) the expression of a nucleic acid molecule encoding Erythropoietin (EPO)) polynucleotides, the modulator may then be employed in further investigative studies of the function of Erythropoietin (EPO) polynucleotides, or for use as a research, diagnostic or therapeutic agent in accordance with the present invention.
Targeting the natural antisense sequence preferably modulates the function of the target gene, for example, the EPO gene (e.g. accession number NM_000799.2, FIG. 2). In a preferred embodiment, the target is an antisense polynucleotide of the Erythropoietin gene. In a preferred embodiment, an antisense oligonucleotide targets sense and/or natural antisense sequences of Erythropoictin (EPO) polynucleotides (e.g. accession number NM_000799.2. FIG. 2), variants, alleles, isoforms, homologs, mutants, derivatives, fragments and complementary sequences thereto. Preferably the oligonucleotide is an antisense molecule and the targets include coding and noncoding regions of antisense and/or sense EPO polynucleotides.
Natural antisense polynucleotides can be identified as described in, e.g., WO 2007/087113 and U.S. Pat. App. Pub. No. 2009/0258925, both titled “Natural Antisense and Non-coding RNA Transcripts as Drug Targets,” incorporated herein by reference in their entirety.
The preferred target segments of the present invention may be also be combined with their respective complementary antisense compounds of the present invention to form stabilized double-stranded (duplexed) oligonucleotides.
Such double stranded oligonucleotide moieties have been shown in the art to modulate target expression and regulate translation as well as RNA processing via an antisense mechanism. Moreover, the double-stranded moieties may be subject to chemical modifications (Fire et al., (1998) Nature, 391, 806-811; Timmons and Fire, (1998) Nature, 395, 854; Timmons et al., (2001) Gene, 263, 103-112; Tabara et al., (1998) Science, 282, 430-431; Montgomery et al., (1998) Proc. Natl. Acad. Sci. USA, 95, 15502-15507; Tuschl et al., (1999) Genes Dev., 13, 3191-3197; Elbashir et al., (2001) Nature, 411, 494-498; Elbashir et al., (2001) Genes Dev. 15, 188-200). For example, such double-stranded moieties have been shown to inhibit the target by the classical hybridization of antisense strand of the duplex to the target, thereby triggering enzymatic degradation of the target (Tijsterman et al., (2002) Science, 295, 694-697).
In a preferred embodiment, an antisense oligonucleotide targets Erythropoietin (EPO) polynucleotides (e.g. accession number NM_000799.2), variants, alleles, isoforms, homologs, mutants, derivatives, fragments and complementary sequences thereto. Preferably the oligonucleotide is an antisense molecule.
In accordance with embodiments of the invention, the target nucleic acid molecule is not limited to Erythropoietin (EPO) alone but extends to any of the isoforms, receptors, homologs and the like of Erythropoietin (EPO) molecules.
In another preferred embodiment, an oligonucleotide targets a natural antisense sequence of EPO polynucleotides, for example, polynucleotides set forth as SEQ ID NO: 3, and any variants, alleles, homologs, mutant, derivatives, fragments and complementary sequences thereto. Examples of antisense oligonucleotides are set forth as SEQ ID NOS: 4 to 6.
In one embodiment, the oligonucleotides are complementary to or bind to nucleic acid sequences of Erythropoictin (EPO) antisense, including without limitation noncoding sense and/or antisense sequences associated with Erythropoietin (EPO) polynucleotides and modulate expression and/or function of Erythropoictin (EPO) molecules.
In another preferred embodiment, the oligonucleotides are complementary to or bind to nucleic acid sequences of EPO natural antisense, set forth as SEQ ID NO: 3 and modulate the expression and/or function of EPO molecules.
In a preferred embodiment, oligonucleotides comprise sequences of at least 5 consecutive nucleotides of SEQ ID NOS: 4 to 6 and modulate expression and/or function of Erythropoietin (EPO) molecules.
The polynucleotide targets comprise EPO, including family members thereof, variants of EPO; mutants of EPO, including SNPs; noncoding sequences of EPO; alleles of EPO; species variants, fragments and the like. Preferably the oligonucleotide is an antisense molecule.
In another preferred embodiment, the oligonucleotide targeting Erythropoietin (EPO) polynucleotides, comprise: antisense RNA, interference RNA (RNAi), short interfering RNA (siRNA); micro interfering RNA (miRNA); a small, temporal RNA (stRNA); or a short, hairpin RNA (shRNA); small RNA-induced gene activation (RNAa); or, small activating RNA (saRNA).
In another preferred embodiment, targeting of Erythropoietin (EPO) polynucleotides, e.g, SEQ ID NO: 3, modulates the expression or function of these targets. In one embodiment, expression or function is up-regulated as compared to a control. In another preferred embodiment, expression or function is down-regulated as compared to a control.
In another preferred embodiment, antisense compound comprise sequences set forth as SEQ ID NOS: 4 to 6. These oligonucleotides can comprise one or more modified nucleotides, shorter or longer fragments, modified bonds and the like.
In another preferred embodiment, SEQ ID NOS: 4 to 6 comprise one or more LNA nucleotides.
In another preferred embodiment, SEQ ID NOS: 4 to 6 comprise one or more LNA nucleotides,
Because of their sequence-specificity, trans-cleaving enzymatic nucleic acid molecules show promise as therapeutic agents for human disease (Usman & McSwiggen, (1995) Ann. Rep. Med. Chem. 30, 285-294; Christoffersen and Marr, (1995) J. Med. Chem. 38, 2023-2037). Enzymatic nucleic acid molecules can be designed to cleave specific RNA targets within the background of cellular RNA. Such a cleavage event renders the mRNA non-functional and abrogates protein expression from that RNA. In this manner, synthesis of a protein associated with a disease state can be selectively inhibited.
In general, enzymatic nucleic acids with RNA cleaving activity act by first binding to a target RNA. Such binding occurs through the target binding portion of a enzymatic nucleic acid which is held in close proximity to an enzymatic portion of the molecule that acts to cleave the target RNA. Thus, the enzymatic nucleic acid first recognizes and then binds a target RNA through complementary base pairing, and once bound to the correct site, acts enzymatically to cut the target RNA. Strategic cleavage of such a target RNA will destroy its ability to direct synthesis of an encoded protein. After an enzymatic nucleic acid has bound and cleaved its RNA target, it is released from that RNA to search for another target and can repeatedly bind and cleave new targets.
Several approaches such as in vitro selection (evolution) strategies (Orgel, (1979) Proc. R. Soc. London, B 205, 435) have been used to evolve new nucleic acid catalysts capable of catalyzing a variety of reactions, such as cleavage and ligation of phosphodiester linkages and amide linkages, (Joyce, (1989) Gene, 82, 83-87; Beaudry et al., (1992) Science 257, 635-641; Joyce, (1992) Scientific American 267, 90-97; Breaker et al., (1994) TIBTECH 12, 268; Bartel et al., (1993) Science 261:1411-1418; Szostak, (1993) TIBS 17, 89-93; Kumar et al., (1995) FASEB J., 9, 1183; Breaker, (1996) Curr. Op. Biotech., 7, 442).
The development of ribozymes that are optimal for catalytic activity would contribute significantly to any strategy that employs RNA-cleaving ribozymes for the purpose of regulating gene expression. The hammerhead ribozyme, for example, functions with a catalytic rate (kcat) of about 1 min-1 in the presence of saturating (10 mM) concentrations of Mg2+ cofactor. An artificial “RNA ligase” ribozyme has been shown to catalyze the corresponding self-modification reaction with a rate of about 100 min-1. In addition, it is known that certain modified hammerhead ribozymes that have substrate binding arms made of DNA catalyze RNA cleavage with multiple turn-over rates that approach 100 min-1. Finally, replacement of a specific residue within the catalytic core of the hammerhead with certain nucleotide analogues gives modified ribozymes that show as much as a 10-fold improvement in catalytic rate. These findings demonstrate that ribozymes can promote chemical transformations with catalytic rates that are significantly greater than those displayed in vitro by most natural self-cleaving ribozymes. It is then possible that the structures of certain selfcleaving ribozymes may be optimized to give maximal catalytic activity, or that entirely new RNA motifs can be made that display significantly faster rates for RNA phosphodiester cleavage.
Intermolecular cleavage of an RNA substrate by an RNA catalyst that fits the “hammerhead” model was first shown in 1987 (Ulhlenbeck, O. C. (1987) Nature. 328: 596-600). The RNA catalyst was recovered and reacted with multiple RNA molecules, demonstrating that it was truly catalytic.
Catalytic RNAs designed based on the “hammerhead” motif have been used to cleave specific target sequences by making appropriate base changes in the catalytic RNA to maintain necessary base pairing with the target sequences (Haseloff and Gerlach, (1988) Nature, 334, 585; Walbot and Bruening, (1988) Nature, 334, 196; Uhlenbeck, O. C. (1987) Nature, 328: 596-600; Koizumi, M., et al. (1988) FEBS Lett., 228: 228-230). This has allowed use of the catalytic RNA to cleave specific target sequences and indicates that catalytic RNAs designed according to the “hammerhead” model may possibly cleave specific substrate RNAs in vivo. (see Haseloff and Gerlach, (1988) Nature, 334, 585; Walbot and Bruening, (1988) Nature, 334, 196; Uhlenbcck, O. C. (1987) Nature, 328: 596-600).
RNA interference (RNAi) has become a powerful tool for modulating gene expression in mammals and mammalian cells. This approach requires the delivery of small interfering RNA (siRNA) either as RNA itself or as DNA, using an expression plasmid or virus and the coding sequence for small hairpin RNAs that are processed to siRNAs. This system enables efficient transport of the pre-siRNAs to the cytoplasm where they are active and permit the use of regulated and tissue specific promoters for gene expression.
In a preferred embodiment, an oligonucleotide or antisense compound comprises an oligomer or polymer of ribonucleic acid (RNA) and/or deoxyribonucleic acid (DNA), or a mimetic, chimera, analog or homolog thereof. This term includes oligonucleotides composed of naturally occurring nucleotides, sugars and covalent internucleoside (backbone) linkages as well as oligonucleotides having non-naturally occurring portions which function similarly. Such modified or substituted oligonucleotides are often desired over native forms because of desirable properties such as, for example, enhanced cellular uptake, enhanced affinity for a target nucleic acid and increased stability in the presence of nucleases.
According to the present invention, the oligonucleotides or “antisense compounds” include antisense oligonucleotides (e.g. RNA, DNA, mimetic, chimera, analog or homolog thereof), ribozymes, external guide sequence (EGS) oligonucleotides, siRNA compounds, single- or double-stranded RNA interference (RNAi) compounds such as siRNA compounds, saRNA, aRNA, and other oligomeric compounds which hybridize to at least a portion of the target nucleic acid and modulate its function. As such, they may be DNA, RNA, DNA-like, RNA-like, or mixtures thereof, or may be mimetics of one or more of these. These compounds may be single-stranded, double-stranded, circular or hairpin oligomeric compounds and may contain structural elements such as internal or terminal bulges, mismatches or loops. Antisense compounds are routinely prepared linearly but can be joined or otherwise prepared to be circular and/or branched. Antisense compounds can include constructs such as, for example, two strands hybridized to form a wholly or partially double-stranded compound or a single strand with sufficient self-complementarity to allow for hybridization and formation of a fully or partially double-stranded compound. The two strands can be linked internally leaving free 3′ or 5′ termini or can be linked to form a continuous hairpin structure or loop. The hairpin structure may contain an overhang on either the 5′ or 3′ terminus producing an extension of single stranded character. The double stranded compounds optionally can include overhangs on the ends. Further modifications can include conjugate groups attached to one of the termini, selected nucleotide positions, sugar positions or to one of the internucleoside linkages. Alternatively, the two strands can be linked via a non-nucleic acid moiety or linker group. When formed from only one strand, dsRNA can take the form of a self-complementary hairpin-type molecule that doubles back on itself to form a duplex. Thus, the dsRNAs can be fully or partially double stranded. Specific modulation of gene expression can be achieved by stable expression of dsRNA hairpins in transgenic cell lines (Hammond et al., (1991) Nat. Rev. Genet., 2, 110-119; Matzke et al., (2001) Curr. Opin. Genet. Dev., 11, 221-227; Sharp, (2001) Genes Dev., 15, 485-490). When formed from two strands, or a single strand that takes the form of a self-complementary hairpin-type molecule doubled back on itself to form a duplex, the two strands (or duplex-forming regions of a single strand) are complementary RNA strands that base pair in Watson-Crick fashion.
Once introduced to a system, the compounds of the invention may elicit the action of one or more enzymes or structural proteins to effect cleavage or other modification of the target nucleic acid or may work via occupancy-based mechanisms. In general, nucleic acids (including oligonucleotides) may be described as “DNA-like” (i.e., generally having one or more 2′-deoxy sugars and, generally, T rather than U bases) or “RNA-like” (i.e., generally having one or more 2′-hydroxyl or 2′-modified sugars and, generally U rather than T bases). Nucleic acid helices can adopt more than one type of structure, most commonly the A- and B-forms. It is believed that, in general, oligonucleotides which have B-form-like structure are “DNA-like” and those which have A-formlike structure are “RNA-like.” In some (chimeric) embodiments, an antisense compound may contain both A- and B-form regions.
The antisense compounds in accordance with this invention can comprise an antisense portion from about 5 to about 80 nucleotides (i.e. from about 5 to about 80 linked nucleosides) in length. This refers to the length of the antisense strand or portion of the antisense compound. In other words, a single-stranded antisense compound of the invention comprises from 5 to about 80 nucleotides, and a double-stranded antisense compound of the invention (such as a dsRNA, for example) comprises a sense and an antisense strand or portion of 5 to about 80 nucleotides in length. One of ordinary skill in the art will appreciate that this comprehends antisense portions of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, or 80 nucleotides in length, or any range therewithin.
In one embodiment, the antisense compounds of the invention have antisense portions of 10 to 50 nucleotides in length. One having ordinary skill in the art will appreciate that this embodies oligonucleotides having antisense portions of 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 nucleotides in length, or any range therewithin. In some embodiments, the oligonucleotides are 15 nucleotides in length.
In one embodiment, the antisense or oligonucleotide compounds of the invention have antisense portions of 12 or 13 to 30 nucleotides in length. One having ordinary skill in the art will appreciate that this embodies antisense compounds having antisense portions of 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 nucleotides in length, or any range therewithin.
In another preferred embodiment, the oligomeric compounds of the present invention also include variants in which a different base is present at one or more of the nucleotide positions in the compound. For example, if the first nucleotide is an adenosine, variants may be produced which contain thymidine, guanosine or cytidine at this position. This may be done at any of the positions of the antisense or dsRNA compounds. These compounds are then tested using the methods described herein to determine their ability to inhibit expression of a target nucleic acid.
In some embodiments, homology, sequence identity or complementarity, between the antisense compound and target is from about 40% to about 60%. In some embodiments, homology, sequence identity or complementarity, is from about 60% to about 70%. In some embodiments, homology, sequence identity or complementarity, is from about 70% to about 80%. In some embodiments, homology, sequence identity or complementarity, is from about 80% to about 90%. In some embodiments, homology, sequence identity or complementarity, is about 90%, about 92%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99% or about 100%.
In another preferred embodiment, the antisense oligonucleotides, such as for example, nucleic acid molecules set forth within SEQ ID NOS: 4 to 6 comprise one or more substitutions or modifications. In one embodiment, the nucleotides are substituted with locked nucleic acids (LNA).
In another preferred embodiment, the oligonucleotides target one or more regions of the nucleic acid molecules sense and/or antisense of coding and/or non-coding sequences associated with EPO and the sequences set forth as SEQ ID NOS: 1, 3. The oligonucleotides are also targeted to overlapping regions of SEQ ID NOS: 1, 3.
Certain preferred oligonucleotides of this invention are chimeric oligonucleotides. “Chimeric oligonucleotides” or “chimeras,” in the context of this invention, are oligonucleotides which contain two or more chemically distinct regions, each made up of at least one nucleotide. These oligonucleotides typically contain at least one region of modified nucleotides that confers one or more beneficial properties (such as, for example, increased nuclease resistance, increased uptake into cells, increased binding affinity for the target) and a region that is a substrate for enzymes capable of cleaving RNA:DNA or RNA:RNA hybrids. By way of example, RNase H is a cellular endonuclease which cleaves the RNA strand of an RNA:DNA duplex. Activation of RNase H, therefore, results in cleavage of the RNA target, thereby greatly enhancing the efficiency of antisense modulation of gene expression. Consequently, comparable results can often be obtained with shorter oligonucleotides when chimeric oligonucleotides are used, compared to phosphorothioate deoxyoligonucleotides hybridizing to the same target region. Cleavage of the RNA target can be routinely detected by gel electrophoresis and, if necessary, associated nucleic acid hybridization techniques known in the art. In one preferred embodiment, a chimeric oligonucleotide comprises at least one region modified to increase target binding affinity, and, usually, a region that acts as a substrate for RNAse H. Affinity of an oligonucleotide for its target (in this case, a nucleic acid encoding ras) is routinely determined by measuring the Tm of an oligonucleotide/target pair, which is the temperature at which the oligonucleotide and target dissociate; dissociation is detected spectrophotometrically. The higher the Tm, the greater is the affinity of the oligonucleotide for the target.
Chimeric antisense compounds of the invention may be formed as composite structures of two or more oligonucleotides, modified oligonucleotides, oligonucleosides and/or oligonucleotides mimetics as described above. Such; compounds have also been referred to in the art as hybrids or gapmers. Representative United States patents that teach the preparation of such hybrid structures comprise, but are not limited to, U.S. Pat. Nos. 5,013,830; 5,149,797; 5,220,007; 5,256,775; 5,366,878; 5,403,711; 5,491,133; 5,565,350; 5,623,065; 5,652,355; 5,652,356; and 5,700,922, each of which is herein incorporated by reference.
In another preferred embodiment, the region of the oligonucleotide which is modified comprises at least one nucleotide modified at the 2′ position of the sugar, most preferably a 2′-Oalkyl, 2′-O-alkyl-O-alkyl or 2′-fluoro-modified nucleotide. In other preferred embodiments, RNA modifications include 2′-fluoro, 2′-amino and 2′ O-methyl modifications on the ribose of pyrimidines, abasic residues or an inverted base at the 3′ end of the RNA. Such modifications are routinely incorporated into oligonucleotides and these oligonucleotides have been shown to have a higher Tm (i.e., higher target binding affinity) than; 2′-deoxyoligonucleotides against a given target. The effect of such increased affinity is to greatly enhance RNAi oligonucleotide inhibition of gene expression. RNAse H is a cellular endonuclease that cleaves the RNA strand of RNA:DNA duplexes; activation of this enzyme therefore results in cleavage of the RNA target, and thus can greatly enhance the efficiency of RNAi inhibition. Cleavage of the RNA target can be routinely demonstrated by gel electrophoresis. In another preferred embodiment, the chimeric oligonucleotide is also modified to enhance nuclease resistance. Cells contain a variety of exo- and endo-nucleases which can degrade nucleic acids. A number of nucleotide and nucleoside modifications have been shown to make the oligonucleotide into which they are incorporated more resistant to nuclease digestion than the native oligodeoxynucleotide. Nuclease resistance is routinely measured by incubating oligonucleotides with cellular extracts or isolated nuclease solutions and measuring the extent of intact oligonucleotide remaining over time, usually by gel electrophoresis. Oligonucleotides which have been modified to enhance their nuclease resistance survive intact for a longer time than unmodified oligonucleotides. A variety of oligonucleotide modifications have been demonstrated to enhance or confer nuclease resistance. Oligonucleotides which contain at least one phosphorothioate modification are presently more preferred. In some cases, oligonucleotide modifications which enhance target binding affinity are also, independently, able to enhance nuclease resistance. Some desirable modifications can be found in De Mesmaeker et al. (1995) Acc. Chem. Res., 28:366-374.
Specific examples of some preferred oligonucleotides envisioned for this invention include those comprising modified backbones, for example, phosphorothioates, phosphotriesters, methyl phosphonates, short chain alkyl or cycloalkyl intersugar linkages or short chain heteroatomic or heterocyclic intersugar linkages. Most preferred are oligonucleotides with phosphorothioate backbones and those with heteroatom backbones, particularly CH2 —NH—O—CH2, CH, —N(CH3)-O—CH2 [known as a methylene(methylimino) or MMI backbone], CH2-O—N(CH3)-CH2, CH2-N(CH3)-N (CH3)-CH2 and O—N(CH3)-CH2-CH2 backbones, wherein the native phosphodiester backbone is represented as O—P—O—CH1). The amide backbones disclosed by De Mesmaeker et al. (1995) Acc. Chem. Res. 28:366-374 are also preferred. Also preferred are oligonucleotides having morpholino backbone structures (Summerton and Weller, U.S. Pat. No. 5,034,506). In other preferred embodiments, such as the peptide nucleic acid (PNA) backbone, the phosphodiester backbone of the oligonucleotide is replaced with a polyamide backbone, the nucleotides being bound directly or indirectly to the aza nitrogen atoms of the polyamide backbone (Nielsen et al. (1991) Science 254, 1497). Oligonucleotides may also comprise one or more substituted sugar moieties. Preferred oligonucleotides comprise one of the following at the 2′ position: OH, SH, SCH3, F, OCN, OCH3 OCH3, OCH3 O(CH2)n CH3, O(CH2)n NH2 or O(CH2)n CH3 where n is from 1 to about 10; C1 to C10 lower alkyl, alkoxyalkoxy, substituted lower alkyl, alkaryl or aralkyl; Cl; Br; CN; CF3; OCF3; O—, S—, or N-alkyl; O—, S—, or N-alkenyl; SOCH3; SO2 CH3; ONO2; NO2; N3; NH2; heterocycloalkyl; heterocycloalkaryl; aminoalkylamino; polyalkylamino; substituted silyl; an RNA cleaving group; a reporter group; an intercalator; a group for improving the pharmacokinetic properties of an oligonucleotide; or a group for improving the pharmacodynamic properties of an oligonucleotide and other substituents having similar properties. A preferred modification includes 2′-methoxyethoxy[2′-O—CH2 CH2 OCH3, also known as 2′-O—(2-methoxyethyl)] (Martin et al., (1995) Helv. Chim. Acta, 78, 486). Other preferred modifications include 2′-methoxy (2′-O—CH3), 2′-propoxy (2′-OCH2 CH2CH3) and 2′-fluoro (2′-F). Similar modifications may also be made at other positions on the oligonucleotide, particularly the 3′ position of the sugar on the 3′ terminal nucleotide and the 5′ position of 5′ terminal nucleotide. Oligonucleotides may also have sugar mimetics such as cyclobutyls in place of the pentofuranosyl group.
Oligonucleotides may also include, additionally or alternatively, nucleobase (often referred to in the art simply as “base”) modifications or substitutions. As used herein, “unmodified” or “natural” nucleotides include adenine (A), guanine (G), thymine (T), cytosine (C) and uracil (U). Modified nucleotides include nucleotides found only infrequently or transiently in natural nucleic acids, e.g., hypoxanthine, 6-methyladenine, 5-Me pyrimidines, particularly 5-methylcytosine (also referred to as 5-methyl-2′ deoxycytosine and often referred to in the art as 5-Me-C), 5-hydroxymethylcytosine (HMC), glycosyl HMC and gentobiosyl HMC, as well as synthetic nucleotides, e.g., 2-aminoadenine, 2-(methylamino)adenine, 2-(imidazolylalkyl)adenine, 2-(aminoalklyamino)adenine or other heterosubstituted alkyladenines, 2-thiouracil, 2-thiothymine, 5-bromouracil, 5-hydroxymethyluracil, 8-azaguanine, 7-deazaguanine, N6 (6-aminohexyl)adenine and 2,6-diaminopurine. (Kornberg. A., DNA Replication, W. H. Freeman & Co., San Francisco, 1980, pp 75-77; Gebeychu, G., (1987) et al. Nucl. Acids Res. 15:4513). A “universal” base known in the art, e.g., inosine, may be included. 5-Me-C substitutions have been shown to increase nucleic acid duplex stability by 0.6-1.2° C. (Sanghvi, Y. S., in Crooke, S. T. and Lebleu, B., eds., Antisense Research and Applications, CRC Press, Boca Raton, 1993, pp. 276-278) and are presently preferred base substitutions.
Another modification of the oligonucleotides of the invention involves chemically linking to the oligonucleotide one or more moieties or conjugates which enhance the activity or cellular uptake of the oligonucleotide. Such moieties include but are not limited to lipid moieties such as a cholesterol moiety, a cholesteryl moiety (Letsinger et al., (1989) Proc. Natl. Acad. Sci. USA 86, 6553), cholic acid (Manoharan et al. (1994) Bioorg. Med. Chem. Let. 4, 1053), a thioether, e.g., hexyl-S-tritylthiol (Manoharan et al. (1992) Ann. N.Y. Acad. Sci. 660, 306; Manoharan et al. (1993) Bioorg. Med. Chem. Let. 3, 2765), a thiocholesterol (Oberhauser et al., (1992) Nucl. Acids Res. 20, 533), an aliphatic chain. e.g., dodecandiol or undecyl residues (Saison-Behmoaras et al. EMBO J. 1991, 10, 111; Kabanov et al. (1990) FEBS Lett. 259, 327; Svinarchuk et al. (1993) Biochimie 75, 49), a phospholipid, e.g., di-hexadecyl-rac-glycerol or triethylammonium 1,2-di-O-hexadecyl-rac-glycero-3-H-phosphonate (Manoharan et al. (1995) Tetrahedron Lett. 36, 3651; Shea et al. (1990) Nucl. Acids Res. 18, 3777), a polyamine or a polyethylene glycol chain (Manoharan et al. (1995) Nucleosides & Nucleotides, 14, 969), or adamantane acetic acid (Manoharan et al. (1995) Tetrahedron Lett. 36, 3651). Oligonucleotides comprising lipophilic moieties, and methods for preparing such oligonucleotides are known in the art, for example, U.S. Pat. Nos. 5,138,045, 5,218,105 and 5,459,255.
It is not necessary for all positions in a given oligonucleotide to be uniformly modified, and in fact more than one of the aforementioned modifications may be incorporated in a single oligonucleotide or even at within a single nucleoside within an oligonucleotide. The present invention also includes oligonucleotides which are chimeric oligonucleotides as hereinbefore defined.
In another embodiment, the nucleic acid molecule of the present invention is conjugated with another moiety including but not limited to abasic nucleotides, polyether, polyamine, polyamides, peptides, carbohydrates, lipid, or polyhydrocarbon compounds. Those skilled in the art will recognize that these molecules can be linked to one or more of any nucleotides comprising the nucleic acid molecule at several positions on the sugar, base or phosphate group.
The oligonucleotides used in accordance with this invention may be conveniently and routinely made through the well-known technique of solid phase synthesis. Equipment for such synthesis is sold by several vendors including Applied Biosystems. Any other means for such synthesis may also be employed; the actual synthesis of the oligonucleotides is well within the talents of one of ordinary skill in the art. It is also well known to use similar techniques to prepare other oligonucleotides such as the phosphorothioates and alkylated derivatives. It is also well known to use similar techniques and commercially available modified amidites and controlled-pore glass (CPG) products such as biotin, fluorescein, acridine or psoralen-modified amidites and/or CPG (available from Glen Research, Sterling Va.) to synthesize fluorescently labeled, biotinylated or other modified oligonucleotides such as cholesterol-modified oligonucleotides.
In accordance with the invention, use of modifications such as the use of LNA monomers to enhance the potency, specificity and duration of action and broaden the routes of administration of oligonucleotides comprised of current chemistries such as MOE, ANA, FANA, PS etc (Uhlman, et al. (2000) Current Opinions in Drug Discovery & Development Vol. 3 No 2). This can be achieved by substituting some of the monomers in the current oligonucleotides by LNA monomers. The LNA modified oligonucleotide may have a size similar to the parent compound or may be larger or preferably smaller. It is preferred that such LNA-modified oligonucleotides contain less than about 70%, more preferably less than about 60%, most preferably less than about 50% LNA monomers and that their sizes are between about 5 and 25 nucleotides, more preferably between about 12 and 20 nucleotides.
Preferred modified oligonucleotide backbones comprise, but not limited to, phosphorothioates, chiral phosphorothioates, phosphorodithioates, phosphotriesters, aminoalkylphosphotriesters, methyl and other alkyl phosphonates comprising 3′alkylene phosphonates and chiral phosphonates, phosphinates, phosphoramidates comprising 3′-amino phosphoramidate and aminoalkylphosphoramidates, thionophosphoramidates, thionoalkylphosphonates, thionoalkylphosphotriesters, and boranophosphates having normal 3′-5′ linkages, 2′-5 linked analogs of these, and those having inverted polarity wherein the adjacent pairs of nucleoside units are linked 3′-5′ to 5′-3′ or 2′-5′ to 5′-2′. Various salts, mixed salts and free acid forms are also included.
Representative United States patents that teach the preparation of the above phosphorus containing linkages comprise, but are not limited to, U.S. Pat. Nos. 3,687,808; 4,469,863; 4,476,301; 5,023,243; 5,177,196; 5,188,897; 5,264,423; 5,276,019; 5,278,302; 5,286,717; 5,321,131; 5,399,676; 5,405,939; 5,453,496; 5,455,233; 5,466,677; 5,476,925; 5,519,126; 5,536,821; 5,541,306; 5,550,111; 5,563,253; 5,571,799; 5,587,361; and 5,625,050, each of which is herein incorporated by reference.
Preferred modified oligonucleotide backbones that do not include a phosphorus atom therein have backbones that are formed by short chain alkyl or cycloalkyl internucleoside linkages, mixed heteroatom and alkyl or cycloalkyl internucleoside linkages, or one or more short chain heteroatomic or heterocyclic internucleoside linkages. These comprise those having morpholino linkages (formed in part from the sugar portion of a nucleoside); siloxane backbones; sulfide, sulfoxide and sulfone backbones; formacetyl and thioformacetyl backbones; methylene formacetyl and thioformacetyl backbones; alkene containing backbones; sulfamate backbones; methyleneimino and methylenehydrazino backbones; sulfonate and sulfonamide backbones; amide backbones; and others having mixed N, O, S and CH2 component parts.
Representative United States patents that teach the preparation of the above oligonucleosides comprise, but are not limited to, U.S. Pat. Nos. 5,034,506; 5,166,315; 5,185,444; 5,214,134; 5,216,141; 5,235,033; 5,264,562; 5,264,564; 5,405,938; 5,434,257; 5,466,677; 5,470,967; 5,489,677; 5,541,307; 5,561,225; 5,596,086; 5,602,240; 5,610,289; 5,602,240; 5,608,046; 5,610,289; 5,618,704; 5,623,070; 5,663,312; 5,633,360; 5,677,437; and 5,677,439, each of which is herein incorporated by reference.
In other preferred oligonucleotide mimetics, both the sugar and the internucleoside linkage, i.e., the backbone, of the nucleotide units are replaced with novel groups. The base units are maintained for hybridization with an appropriate nucleic acid target compound. One such oligomeric compound, an oligonucleotide mimetic that has been shown to have excellent hybridization properties, is referred to as a peptide nucleic acid (PNA). In PNA compounds, the sugar-backbone of an oligonucleotide is replaced with an amide containing backbone, in particular an aminoethylglycine backbone. The nucleobases are retained and are bound directly or indirectly to aza nitrogen atoms of the amide portion of the backbone. Representative United States patents that teach the preparation of PNA compounds comprise, but are not limited to, U.S. Pat. Nos. 5,539,082; 5,714,331; and 5,719,262, each of which is herein incorporated by reference. Further teaching of PNA compounds can be found in Nielsen, et al. (1991) Science 254, 1497-1500.
In another preferred embodiment of the invention the oligonucleotides with phosphorothioate backbones and oligonucleosides with heteroatom backbones, and in particular —CH2-NH—O—CH2-, —CH2-N(CH3)-O—CH2-known as a methylene (methylimino) or MMI backbone, —CH2-O—N(CH3)-CH2-, —CH2N(CH3)-N(CH3) CH2- and —O—N(CH3)-CH2-CH2- wherein the native phosphodiester backbone is represented as —O—P—O—CH2- of the above referenced U.S. Pat. No. 5,489,677, and the amide backbones of the above referenced U.S. Pat. No. 5,602,240. Also preferred are oligonucleotides having morpholino backbone structures of the above-referenced U.S. Pat. No. 5,034,506.
Modified oligonucleotides may also contain one or more substituted sugar moieties. Preferred oligonucleotides comprise one of the following at the 2′ position; OH; F; O—, S—, or N-alkyl; O—, S—, or N-alkenyl; O—, S—or N-alkynyl; or O alkyl-O-alkyl, wherein the alkyl, alkenyl and alkynyl may be substituted or unsubstituted C to CO alkyl or C2 to CO alkenyl and alkynyl. Particularly preferred are O(CH2)n OmCH3, O(CH2)n, OCH3, O(CH2)nNH2, O(CH2)nCH3, O(CH2)nONH2, and O(CH2nON(CH2)nCH3)2 where n and m can be from 1 to about 10. Other preferred oligonucleotides comprise one of the following at the 2′ position; C to CO, (lower alkyl, substituted lower alkyl, alkaryl, aralkyl, O-alkaryl or O-aralkyl, SH, SCH3, OCN, Cl, Br, CN, CF3, OCF3, SOCH3, SO2CH3, ONO2, NO2, N3, NH2, heterocycloalkyl, heterocycloalkaryl, aminoalkylamino, polyalkylamino, substituted silyl, an RNA cleaving group, a reporter group, an intercalator, a group for improving the pharmacokinetic properties of an oligonucleotide, or a group for improving the pharmacodynamic properties of an oligonucleotide, and other substituents having similar properties. A preferred modification comprises 2′-methoxyethoxy (2′-O—CH2CH2OCH3, also known as 2′-O-(2-methoxyethyl) or 2′-MOE) (Martin et al., (1995) Helv. Chim. Acta, 78, 486-504) i.e., an alkoxyalkoxy group. A further preferred modification comprises 2′-dimethylaminooxyethoxy, i.e., a O(CH2)2ON(CH3)2 group, also known as 2′-DMAOE, as described in examples herein below, and 2′-dimethylaminoethoxyethoxy (also known in the art as 2′-O-dimethylaminoethoxyethyl or 2′-DMAEOE). i.e., 2′-O—CH2-O—CH2-N(CH2)2.
Other preferred modifications comprise 2′-methoxy (2′-O CH3), 2′-aminopropoxy (2′-O CH2CH2CH2NH2) and 2′-fluoro (2′-F). Similar modifications may also be made at other positions on the oligonucleotide, particularly the 3′ position of the sugar on the 3′ terminal nucleotide or in 2′-5′ linked oligonucleotides and the 5′ position of 5′ terminal nucleotide. Oligonucleotides may also have sugar mimetics such as cyclobutyl moieties in place of the pentofuranosyl sugar. Representative United States patents that teach the preparation of such modified sugar structures comprise, but are not limited to, U.S. Pat. Nos. 4,981,957; 5,118,800; 5,319,080; 5,359,044; 5,393,878; 5,446,137; 5,466,786; 5,514,785; 5,519,134; 5,567,811; 5,576,427; 5,591,722; 5,597,909; 5,610,300; 5,627,053; 5,639,873; 5,646, 265; 5,658,873; 5,670,633; and 5,700,920, each of which is herein incorporated by reference.
Oligonucleotides may also comprise nucleobase (often referred to in the art simply as “base”) modifications or substitutions. As used herein, “unmodified” or “natural” nucleotides comprise the purine bases adenine (A) and guanine (G), and the pyrimidine bases thymine (T), cytosine (C) and uracil (U). Modified nucleotides comprise other synthetic and natural nucleotides such as 5-methylcytosine (5-me-C), 5-hydroxymethyl cytosine, xanthine, hypoxanthine, 2-aminoadenine, 6-methyl and other alkyl derivatives of adenine and guanine, 2-propyl and other alkyl derivatives of adenine and guanine, 2-thiouracil, 2-thiothymine and 2-thiocytosine, 5-halouracil and cytosine, 5-propynyl uracil and cytosine, 6-azo uracil, cytosine and thymine, 5-uracil (pseudo-uracil), 4-thiouracil, 8-halo, 8-amino, 8-thiol, 8-thioalkyl, 8-hydroxyl and other 8-substituted adenines and guanines, 5-halo particularly 5-bromo, 5-trifluoromethyl and other 5-substituted uracils and cytosines, 7-methylquanine and 7-methyladenine, 8-azaguanine and 8-azaadenine, 7-deazaguanine and 7-deazaadenine and 3-deazaguanine and 3-deazaadenine.
Further, nucleotides comprise those disclosed in U.S. Pat. No. 3,687,808, those disclosed in ‘The Concise Encyclopedia of Polymer Science And Engineering’, pages 858-859. Kroschwitz, J. I., ed. John Wiley & Sons, 1990, those disclosed by Englisch et al., ‘Angewandle Chemie, International Edition’, 1991, 30, page 613, and those disclosed by Sanghvi, Y. S., Chapter 15, ‘Antisense Research and Applications’, pages 289-302, Crooke, S. T. and Lebleu, B. ca., CRC Press, 1993. Certain of these nucleotides are particularly useful for increasing the binding affinity of the oligomeric compounds of the invention. These comprise 5-substituted pyrimidines, 6-azapyrimidines and N-2, N-6 and 0-6 substituted purines, comprising 2-aminopropyladenine, 5-propynyluracil and 5-propynylcytosine. 5-methylcytosine substitutions have been shown to increase nucleic acid duplex stability by 0.6-1.2° C. (Sanghvi, Y. S., Crooke, S. T. and Lebleu, B., eds, ‘Antisense Research and Applications’, CRC Press, Boca Raton, 1993, pp. 276-278) and are presently preferred base substitutions, even more particularly when combined with 2′-Omethoxyethyl sugar modifications.
Representative United States patents that teach the preparation of the above noted modified nucleotides as well as other modified nucleotides comprise, but are not limited to, U.S. Pat. No. 3,687,808, as well as U.S. Pat. Nos. 4,845,205; 5,130,302; 5,134,066; 5,175,273; 5,367,066; 5,432,272; 5,457,187; 5,459,255; 5,484,908; 5,502,177; 5,525,711; 5,552,540; 5,587,469; 5,596,091; 5,614,617; 5,750,692, and 5,681,941, each of which is herein incorporated by reference.
Another modification of the oligonucleotides of the invention involves chemically linking to the oligonucleotide one or more moieties or conjugates, which enhance the activity, cellular distribution, or cellular uptake of the oligonucleotide.
Such moieties comprise but are not limited to, lipid moieties such as a cholesterol moiety (Letsinger et al., (1989) Proc. Natl. Acad. Sci. USA, 86, 6553-6556), cholic acid (Manoharan et al., (1994) Bioorg. Med. Chem. Let., 4, 1053-1060), a thioether, e.g., hexyl-S-tritylthiol (Manoharan et al., (1992) Ann. N. Y. Acad. Sci., 660, 306-309; Manoharan et al., (1993) Bioorg. Med. Chem. Let., 3, 2765-2770), a thiocholesterol (Oberhauser et al., (1992) Nucl. Acids Res., 20, 533-538), an aliphatic chain, e.g., dodecandiol or undecyl residues (Kabanov et al., (1990) FEBS Lett., 259, 327-330; Svinarchuk et al., (1993) Biochimie 75, 49-54), a phospholipid, e.g., di-hexadecyl-rac-glycerol or triethylammonium 1,2-di-O-hexadecyl-rac-glycero-3-H-phosphonate (Manoharan et al., (1995) Tetrahedron Lett., 36, 3651-3654; Shea et al., (1990) Nucl. Acids Res., 18, 3777-3783), a polyamine or a polyethylene glycol chain (Mancharan et al., (1995) Nucleosides & Nucleotides, 14, 969-973), or adamantane acetic acid (Manoharan et al., (1995) Tetrahedron Lett., 36, 3651-3654), a palmityl moiety (Mishra et al., (1995) Biochim. Biophys. Acta, 1264, 229-237), or an octadecylamine or hexylamino-carbonyl-t oxycholesterol moiety (Crooke et al. (1996) J. Pharmacol. Exp. Ther., 277, 923-937).
Representative United States patents that teach the preparation of such oligonucleotides conjugates comprise, but are not limited to, U.S. Pat. Nos. 4,828,979; 4,948,882; 5,218,105; 5,525,465; 5,541,313; 5,545,730; 5,552,538; 5,578,717, 5,580,731; 5,580,731; 5,591,584; 5,109,124; 5,118,802; 5,138,045; 5,414,077; 5,486,603; 5,512,439; 5,578,718; 5,608,046; 4,587,044; 4,605,735; 4,667,025; 4,762,779; 4,789,737; 4,824,941; 4,835,263; 4,876,335; 4,904,582; 4,958,013; 5,082,830; 5,112,963; 5,214,136; 5,082,830; 5,112,963; 5,214,136; 5,245,022; 5,254,469; 5,258,506; 5,262,536; 5,272,250; 5,292,873; 5,317,098; 5,371,241, 5,391,723; 5,416,203, 5,451,463; 5,510,475; 5,512,667; 5,514,785; 5,565,552; 5,567,810; 5,574,142; 5,585,481; 5,587,371; 5,595,726; 5,597,696; 5,599,923; 5,599,928 and 5,688,941, each of which is herein incorporated by reference.
Drug discovery: The compounds of the present invention can also be applied in the areas of drug discovery and target validation. The present invention comprehends the use of the compounds and preferred target segments identified herein in drug discovery efforts to elucidate relationships that exist between Erythropoietin (EPO) polynucleotides and a disease state, phenotype, or condition. These methods include detecting or modulating Erythropoictin (EPO) polynucleotides comprising contacting a sample, tissue, cell, or organism with the compounds of the present invention, measuring the nucleic acid or protein level of Erythropoictin (EPO) polynucleotides and/or a related phenotypic or chemical endpoint at some time after treatment, and optionally comparing the measured value to a non-treated sample or sample treated with a further compound of the invention. These methods can also be performed in parallel or in combination with other experiments to determine the function of unknown genes for the process of target validation or to determine the validity of a particular gene product as a target for treatment or prevention of a particular disease, condition, or phenotype.
Assessing Up-regulation or Inhibition of Gene Expression:
Transfer of an exogenous nucleic acid into a host cell or organism can be assessed by directly detecting the presence of the nucleic acid in the cell or organism. Such detection can be achieved by several methods well known in the art. For example, the presence of the exogenous nucleic acid can be detected by Southern blot or by a polymerase chain reaction (PCR) technique using primers that specifically amplify nucleotide sequences associated with the nucleic acid. Expression of the exogenous nucleic acids can also be measured using conventional methods including gene expression analysis. For instance, mRNA produced from an exogenous nucleic acid can be detected and quantified using a Northern blot and reverse transcription PCR (RT-PCR).
Expression of RNA from the exogenous nucleic acid can also be detected by measuring an enzymatic activity or a reporter protein activity. For example, antisense modulatory activity can be measured indirectly as a decrease or increase in target nucleic acid expression as an indication that the exogenous nucleic acid is producing the effector RNA. Based on sequence conservation, primers can be designed and used to amplify coding regions of the target genes. Initially, the most highly expressed coding region from each gene can be used to build a model control gene, although any coding or non coding region can be used. Each control gene is assembled by inserting each coding region between a reporter coding region and its poly(A) signal. These plasmids would produce an mRNA with a reporter gene in the upstream portion of the gene and a potential RNAi target in the 3′ non-coding region. The effectiveness of individual antisense oligonucleotides would be assayed by modulation of the reporter gene. Reporter genes useful in the methods of the present invention include acetohydroxyacid synthase (AHAS), alkaline phosphatase (AP), beta galactosidase (LacZ), beta glucoronidase (GUS), chloramphenicol acetyltransferase (CAT), green fluorescent protein (GFP), red fluorescent protein (RFP), yellow fluorescent protein (YFP), cyan fluorescent protein (CFP), horseradish peroxidase (HRP), luciferase (Luc), nopaline synthase (NOS), octopine synthase (OCS), and derivatives thereof. Multiple selectable markers are available that confer resistance to ampicillin, bleomycin, chloramphenicol, gentamycin, hygromycin, kanamycin, lincomycin, methotrexate, phosphinothricin, puromycin, and tetracycline. Methods to determine modulation of a reporter gene are well known in the art, and include, but are not limited to, fluorometric methods (e.g. fluorescence spectroscopy, Fluorescence Activated Cell Sorting (FACS), fluorescence microscopy), antibiotic resistance determination.
Kits, Research Reagents, Diagnostics, and Therapeutics
The compounds of the present invention can be utilized for diagnostics, therapeutics, and prophylaxis, and as research reagents and components of kits. Furthermore, antisense oligonucleotides, which are able to inhibit gene expression with exquisite specificity, are often used by those of ordinary skill to elucidate the function of particular genes or to distinguish between functions of various members of a biological pathway.
For use in kits and diagnostics and in various biological systems, the compounds of the present invention, either alone or in combination with other compounds or therapeutics, are useful as tools in differential and/or combinatorial analyses to elucidate expression patterns of a portion or the entire complement of genes expressed within cells and tissues.
As used herein the term “biological system” or “system” is defined as any organism, cell, cell culture or tissue that expresses, or is made competent to express products of the Erythropoietin (EPO) genes. These include, but are not limited to, humans, transgenic animals, cells, cell cultures, tissues, xenografts, transplants and combinations thereof.
As one non limiting example, expression patterns within cells or tissues treated with one or more antisense compounds are compared to control cells or tissues not treated with antisense compounds and the patterns produced are analyzed for differential levels of gene expression as they pertain, for example, to disease association, signaling pathway, cellular localization, expression level, size, structure or function of the genes examined. These analyses can be performed on stimulated or unstimulated cells and in the presence or absence of other compounds that affect expression patterns.
Examples of methods of gene expression analysis known in the art include DNA arrays or microarrays (Brazma and Vilo, (2000) FEBS Lett., 480, 17-24; Celis, et al., (2000) FEBS Lett., 480, 2-16), SAGE (serial analysis of gene expression) (Madden, et al., (2000) Drug Discov. Today, 5, 415-425), READS (restriction enzyme amplification of digested cDNAs) (Prashar and Weissman, (1999) Methods Enzymol., 303, 258-72), TOGA (total gene expression analysis) (Sutcliffe, et al., (2000) Proc. Natl. Acad. Sci. U.S.A., 97, 1976-81), protein arrays and proteomics (Celis, et al., (2000) FEBS Lett., 480, 2-16; Jungblut, et al., Electrophoresis, 1999, 20, 2100-10), expressed sequence tag (EST) sequencing (Celis, et al., FEBS Lett., 2000, 480, 2-16; Larsson, et al., J. Biotechnol., 2000, 80, 143-57), subtractive RNA fingerprinting (SuRF) (Fuchs, et al., (2000) Anal. Biochem. 286, 91-98; Larson, et al., (2000) Cytometry 41, 203-208), subtractive cloning, differential display (DD) (Jurecic and Belmont, (2000) Curr. Opin. Microbiol. 3, 316-21), comparative genomic hybridization (Carulli, et al., (1998) J. Cell Biochem. Suppl., 31, 286-96), FISH (fluorescent in situ hybridization) techniques (Going and Gusterson, (1999) Eur. J. Cancer. 35, 1895-904) and mass spectrometry methods (To, Comb. (2000) Chem. High Throughput Screen, 3, 235-41).
The compounds of the invention are useful for research and diagnostics, because these compounds hybridize to nucleic acids encoding Erythropoietin (EPO). For example, oligonucleotides that hybridize with such efficiency and under such conditions as disclosed herein as to be effective Erythropoietin (EPO) modulators are effective primers or probes under conditions favoring gene amplification or detection, respectively. These primers and probes are useful in methods requiring the specific detection of nucleic acid molecules encoding Erythropoietin (EPO) and in the amplification of said nucleic acid molecules for detection or for use in further studies of Erythropoietin (EPO). Hybridization of the antisense oligonucleotides, particularly the primers and probes, of the invention with a nucleic acid encoding Erythropoietin (EPO) can be detected by means known in the art. Such means may include conjugation of an enzyme to the oligonucleotide, radiolabeling of the oligonucleotide, or any other suitable detection means. Kits using such detection means for detecting the level of Erythropoietin (EPO) in a sample may also be prepared.
The specificity and sensitivity of antisense are also harnessed by those of skill in the art for therapeutic uses. Antisense compounds have been employed as therapeutic moieties in the treatment of disease states in animals, including humans. Antisense oligonucleotide drugs have been safely and effectively administered to humans and numerous clinical trials are presently underway. It is thus established that antisense compounds can be useful therapeutic modalities that can be configured to be useful in treatment regimes for the treatment of cells, tissues and animals, especially humans.
For therapeutics, an animal, preferably a human, suspected of having a disease or disorder which can be treated by modulating the expression of Erythropoietin (EPO) polynucleotides is treated by administering antisense compounds in accordance with this invention. For example, in one non-limiting embodiment, the methods comprise the step of administering to the animal in need of treatment, a therapeutically effective amount of Erythropoictin (EPO) modulator. The Erythropoietin (EPO) modulators of the present invention effectively modulate the activity of the Erythropoietin (EPO) or modulate the expression of the Erythropoietin (EPO) protein. In one embodiment, the activity or expression of Erythropoietin (EPO) in an animal is inhibited by about 10% as compared to a control. Preferably, the activity or expression of Erythropoietin (EPO) in an animal is inhibited by about 30%. More preferably, the activity or expression of Erythropoietin (EPO) in an animal is inhibited by 50% or more. Thus, the oligomeric compounds modulate expression of Erythropoietin (EPO) mRNA by at least 10%, by at least 50%, by at least 25%, by at least 30%, by at least 40%, by at least 50%, by at least 60%, by at least 70%, by at least 75%, by at least 80%, by at least 85%, by at least 90%, by at least 95%, by at least 98%, by at least 99%, or by 100% as compared to a control.
In one embodiment, the activity or expression of Erythropoietin (EPO) and/or in an animal is increased by about 10% as compared to a control. Preferably, the activity or expression of Erythropoietin (EPO) in an animal is increased by about 30%. More preferably, the activity or expression of Erythropoietin (EPO) in an animal is increased by 50% or more. Thus, the oligomeric compounds modulate expression of Erythropoictin (EPO) mRNA by at least 10%, by at least 50%, by at least 25%, by at least 30%, by at least 40%, by at least 50%, by at least 60%, by at least 70%, by at least 75%, by at least 80%, by at least 85%, by at least 90%, by at least 95%, by at least 98%, by at least 99%, or by 100% as compared to a control.
For example, the reduction of the expression of Erythropoietin (EPO) may be measured in serum, blood, adipose tissue, liver or any other body fluid, tissue or organ of the animal, using methods described in the literature and known to those of skill in the art. Preferably, the cells contained within said fluids, tissues or organs being analyzed contain a nucleic acid molecule encoding Erythropoietin (EPO) peptides and/or the Erythropoietin (EPO) protein itself.
The compounds of the invention can be utilized in pharmaceutical compositions by adding an effective amount of a compound to a suitable pharmaceutically acceptable diluent or carrier. Use of the compounds and methods of the invention may also be useful prophylactically.
Conjugates
Another modification of the oligonucleotides of the invention involves chemically linking to the oligonucleotide one or more moieties or conjugates that enhance the activity, cellular distribution or cellular uptake of the oligonucleotide. These moieties or conjugates can include conjugate groups covalently bound to functional groups such as primary or secondary hydroxyl groups. Conjugate groups of the invention include intercalators, reporter molecules, polyamines, polyamides, polyethylene glycols, polyethers, groups that enhance the pharmacodynamic properties of oligomers, and groups that enhance the pharmacokinetic properties of oligomers. Typical conjugate groups include cholesterols, lipids, phospholipids, biotin, phenazine, folate, phenanthridine, anthraquinone, acridine, fluoresceins, rhodamines, coumarins, and dyes. Groups that enhance the pharmacodynamic properties, in the context of this invention, include groups that improve uptake, enhance resistance to degradation, and/or strengthen sequence-specific hybridization with the target nucleic acid. Groups that enhance the pharmacokinetic properties, in the context of this invention, include groups that improve uptake, distribution, metabolism or excretion of the compounds of the present invention. Representative conjugate groups are disclosed in International Patent Application No. PCT/US92/09196, filed Oct. 23, 1992, and U.S. Pat. No. 6,287,860. “Antisense inhibition of MEKK2 expression,” both of which are incorporated herein by reference. Conjugate moieties include, but are not limited to, lipid moieties such as a cholesterol moiety, cholic acid, a thioether, e.g., hexyl-5-tritylthiol, a thiocholesterol, an aliphatic chain, e.g., dodecandiol or undecyl residues, a phospholipid, e.g., di-hexadecyl-rac-glycerol or triethylammonium 1,2-di-O-hexadecyl-rac-glycero-3-Hphosphonate, a polyamine or a polyethylene glycol chain, or adamantane acetic acid, a palmityl moiety, or an octadecylamine or hexylamino-carbonyl-oxycholesterol moiety. Oligonucleotides of the invention may also be conjugated to active drug substances, for example, aspirin, warfarin, phenylbutazone, ibuprofen, suprofen, fenbufen, ketoprofen, (S)-(+)-pranoprofen, carprofen, dansylsarcosine, 2,3,5-triiodobenzoic acid, flufenamic acid, folinic acid, a benzothiadiazide, chlorothiazide, a diazepine, indomethicin, a barbiturate, a cephalosporin, a sulfa drug, an antidiabetic, an antibacterial or an antibiotic.
Representative United States patents that teach the preparation of such oligonucleotides conjugates include, but are not limited to, U.S. Pat. Nos. 4,828,979; 4,948,882; 5,218,105; 5,525,465; 5,541,313; 5,545,730; 5,552,538; 5,578,717, 5,580,731; 5,580,731; 5,591,584; 5,109,124; 5,118,802; 5,138,045; 5,414,077; 5,486,603; 5,512,439; 5,578,718; 5,608,046; 4,587,044; 4,605,735; 4,667,025; 4,762,779; 4,789,737; 4,824,941; 4,835,263; 4,876,335; 4,904,582; 4,958,013; 5,082,830; 5,112,963; 5,214,136; 5,082,830; 5,112,963; 5,214,136; 5,245,022; 5,254,469; 5,258,506; 5,262,536; 5,272,250; 5,292,873; 5,317,098; 5,371,241, 5,391,723; 5,416,203, 5,451,463; 5,510,475; 5,512,667; 5,514,785; 5,565,552; 5,567,810; 5,574,142; 5,585,481; 5,587,371; 5,595,726; 5,597,696; 5,599,923; 5,599,928 and 5,688,941.
Formulations
The compounds of the invention may also be admixed, encapsulated, conjugated or otherwise associated with other molecules, molecule structures or mixtures of compounds, as for example, liposomes, receptor-targeted molecules, oral, rectal, topical or other formulations, for assisting in uptake, distribution and/or absorption. Representative United States patents that teach the preparation of such uptake, distribution and/or absorption-assisting formulations include, but are not limited to, U.S. Pat. Nos. 5,108,921; 5,354,844; 5,416,016; 5,459,127; 5,521,291; 5,543,165; 5,547,932; 5,583,020; 5,591,721; 4,426,330; 4,534,899; 5,013,556; 5,108,921; 5,213,804; 5,227,170; 5,264,221; 5,356,633; 5,395,619; 5,416,016; 5,417,978; 5,462,854; 5,469,854; 5,512,295; 5,527,528; 5,534,259; 5,543,152; 5,556,948; 5,580,575; and 5,595,756, each of which is herein incorporated by reference.
Although, the antisense oligonucleotides do not need to be administered in the context of a vector in order to modulate a target expression and/or function, embodiments of the invention relates to expression vector constructs for the expression of antisense oligonucleotides, comprising promoters, hybrid promoter gene sequences and possess a strong constitutive promoter activity, or a promoter activity which can be induced in the desired case.
In an embodiment, invention practice involves administering at least one of the foregoing antisense oligonucleotides with a suitable nucleic acid delivery system. In one embodiment, that system includes a non-viral vector operably linked to the polynucleotide. Examples of such non-viral vectors include the oligonucleotide alone (e.g., any one or more of SEQ ID NOS: 4 to 6) or in combination with a suitable protein, polysaccharide or lipid formulation.
Additionally suitable nucleic acid delivery systems include viral vector, typically sequence from at least one of an adenovirus, adenovirus-associated virus (AAV), helper-dependent adenovirus, retrovirus, or hemagglutinatin virus of Japan-liposome (HVJ) complex. Preferably, the viral vector comprises a strong eukaryotic promoter operably linked to the polynucleotide e.g., a cytomegalovirus (CMV) promoter.
Additionally preferred vectors include viral vectors, fusion proteins and chemical conjugates. Retroviral vectors include Moloney murine leukemia viruses and HIV-based viruses. One preferred HIV-based viral vector comprises at least two vectors wherein the gag and pol genes are from an HIV genome and the env gene is from another virus. DNA viral vectors are preferred. These vectors include pox vectors such as orthopox or avipox vectors, herpesvirus vectors such as a herpes simplex 1 virus (HSV) vector [Geller, A. I. et al., (1995) J. Neurochem, 64: 487; Lim, F., et al., in DNA Cloning: Mammalian Systems, D. Glover, Ed. (Oxford Univ. Press, Oxford England) (1995); Geller, A. I. et al., (1993) Proc Natl. Acad. Sci.; U.S.A.: 90 7603; Geller, A. I., et al., (1990) Proc Natl. Acad. Sci USA: 87:1149], Adenovirus Vectors (LeGal LaSalle et al., Science, 259:988 (1993); Davidson, et al., (1993) Nat. Genet. 3: 219; Yang, et al., (1995) J. Virol. 69: 2004) and Adeno-associated Virus Vectors (Kaplitt, M. G., et al., (1994) Nat. Genet. 8:148).
The antisense compounds of the invention encompass any pharmaceutically acceptable salts, esters, or salts of such esters, or any other compound which, upon administration to an animal, including a human, is capable of providing (directly or indirectly) the biologically active metabolite or residue thereof.
The term “pharmaceutically acceptable salts” refers to physiologically and pharmaceutically acceptable salts of the compounds of the invention: i.e., salts that retain the desired biological activity of the parent compound and do not impart undesired toxicological effects thereto. For oligonucleotides, preferred examples of pharmaceutically acceptable salts and their uses are further described in U.S. Pat. No. 6,287,860, which is incorporated herein by reference.
The present invention also includes pharmaceutical compositions and formulations that include the antisense compounds of the invention. The pharmaceutical compositions of the present invention may be administered in a number of ways depending upon whether local or systemic treatment is desired and upon the area to be treated. Administration may be topical (including ophthalmic and to mucous membranes including vaginal and rectal delivery), pulmonary, e.g., by inhalation or insufflation of powders or aerosols, including by nebulizer, intratracheal, intranasal, epidermal and transdermnal), oral or parenteral. Parenteral administration includes intravenous, intraarterial, subcutaneous, intraperitoneal or intramuscular injection or infusion; or intracranial, e.g., intrathecal or intraventricular, administration. Oligonucleotides with at least one 2′-O-methoxyethyl modification are believed to be particularly useful for oral administration. Pharmaceutical compositions and formulations for topical administration may include transdermal patches, ointments, lotions, creams, gels, drops, suppositories, sprays, liquids and powders. Conventional pharmaceutical carriers, aqueous, powder or oily bases, thickeners and the like may be necessary or desirable. Coated condoms, gloves and the like may also be useful.
The pharmaceutical formulations of the present invention, which may conveniently be presented in unit dosage form, may be prepared according to conventional techniques well known in the pharmaceutical industry. Such techniques include the step of bringing into association the active ingredients with the pharmaceutical carrier(s) or excipient(s). In general, the formulations are prepared by uniformly and intimately bringing into association the active ingredients with liquid carriers or finely divided solid carriers or both, and then, if necessary, shaping the product.
The compositions of the present invention may be formulated into any of many possible dosage forms such as, but not limited to, tablets, capsules, gel capsules, liquid syrups, soft gels, suppositories, and enemas. The compositions of the present invention may also be formulated as suspensions in aqueous, non-aqueous or mixed media. Aqueous suspensions may further contain substances that increase the viscosity of the suspension including, for example, sodium carboxymethylcellulose, sorbitol and/or dextran. The suspension may also contain stabilizers.
Pharmaceutical compositions of the present invention include, but are not limited to, solutions, emulsions, foams and liposome-containing formulations. The pharmaceutical compositions and formulations of the present invention may comprise one or more penetration enhancers, carriers, excipients or other active or inactive ingredients.
Emulsions are typically heterogeneous systems of one liquid dispersed in another in the form of droplets usually exceeding 0.1 μm in diameter. Emulsions may contain additional components in addition to the dispersed phases, and the active drug that may be present as a solution in either the aqueous phase, oily phase or itself as a separate phase. Microemulsions are included as an embodiment of the present invention. Emulsions and their uses are well known in the art and are further described in U.S. Pat. No. 6,287,860.
Formulations of the present invention include liposomal formulations. As used in the present invention, the term “liposome” means a vesicle composed of amphiphilic lipids arranged in a spherical bilayer or bilayers. Liposomes are unilamellar or multilamellar vesicles which have a membrane formed from a lipophilic material and an aqueous interior that contains the composition to be delivered. Cationic liposomes are positively charged liposomes that are believed to interact with negatively charged DNA molecules to form a stable complex. Liposomes that are pH-sensitive or negatively-charged are believed to entrap DNA rather than complex with it. Both cationic and noncationic liposomes have been used to deliver DNA to cells.
Liposomes also include “sterically stabilized” liposomes, a term which, as used herein, refers to liposomes comprising one or more specialized lipids. When incorporated into liposomes, these specialized lipids result in liposomes with enhanced circulation lifetimes relative to liposomeslacking such specialized lipids. Examples of sterically stabilized liposomes are those in which part of the vesicle-forming lipid portion of the liposome comprises one or more glycolipids or is derivatized with one or more hydrophilic polymers, such as a polyethylene glycol (PEG) moiety. Liposomes and their uses are further described in U.S. Pat. No. 6,287,860.
The pharmaceutical formulations and compositions of the present invention may also include surfactants. The use of surfactants in drug products, formulations and in emulsions is well known in the art. Surfactants and their uses are further described in U.S. Pat. No. 6,287,860, which is incorporated herein by reference.
In one embodiment, the present invention employs various penetration enhancers to effect the efficient delivery of nucleic acids, particularly oligonucleotides. In addition to aiding the diffusion of non-lipophilic drugs across cell membranes, penetration enhancers also enhance the permeability of lipophilic drugs. Penetration enhancers may be classified as belonging to one of five broad categories, i.e., surfactants, fatty acids, bile salts, chelating agents, and non-chelating nonsurfactants. Penetration enhancers and their uses are further described in U.S. Pat. No. 6,287,860, which is incorporated herein by reference.
One of skill in the art will recognize that formulations are routinely designed according to their intended use, i.e. route of administration.
Preferred formulations for topical administration include those in which the oligonucleotides of the invention are in admixture with a topical delivery agent such as lipids, liposomes, fatty acids, fatty acid esters, steroids, chelating agents and surfactants. Preferred lipids and liposomes include neutral (e.g. diolcoyl-phosphatidyl DOPE ethanolamine, dimyristoylphosphatidyl choline DMPC, distearolyphosphatidyl choline) negative (e.g. dimyristoylphosphatidyl glycerol DMPG) and cationic (e.g. dioleoyltetramethylaminopropyl DOTAP and dioleoyl-phosphatidyl ethanolamine DOTMA).
For topical or other administration, oligonucleotides of the invention may be encapsulated within liposomes or may form complexes thereto, in particular to cationic liposomes. Alternatively, oligonucleotides may be complexed to lipids, in particular to cationic lipids. Preferred fatty acids and esters, pharmaceutically acceptable salts thereof, and their uses are further described in U.S. Pat. No. 6,287,860.
Compositions and formulations for oral administration include powders or granules, microparticulates, nanoparticulates, suspensions or solutions in water or non-aqueous media, capsules, gel capsules, sachets, tablets or minitablets. Thickeners, flavoring agents, diluents, emulsifiers, dispersing aids or binders may be desirable. Preferred oral formulations are those in which oligonucleotides of the invention are administered in conjunction with one or more penetration enhancers surfactants and chelators. Preferred surfactants include fatty acids and/or esters or salts thereof, bile acids and/or salts thereof. Preferred bile acids/salts and fatty acids and their uses are further described in U.S. Pat. No. 6,287,860, which is incorporated herein by reference. Also preferred are combinations of penetration enhancers, for example, fatty acids/salts in combination with bile acids/salts. A particularly preferred combination is the sodium salt of lauric acid, cupric acid and UDCA. Further penetration enhancers include polyoxyethylene-9-lauryl ether, polyoxyethylene-20-cetyl ether. Oligonucleotides of the invention may be delivered orally, in granular form including sprayed dried particles, or complexed to form micro or nanoparticles. Oligonucleotide complexing agents and their uses are further described in U.S. Pat. No. 6,287,860, which is incorporated herein by reference. In vivo administration of interfering RNAs has been described, e.g., in U.S. Pat. No. 7,528,118, “RNAi modulation of ApoB and uses thereof,” incorporated herein by reference in its entirety.
Compositions and formulations for parenteral, intrathecal or intraventricular administration may include sterile aqueous solutions that may also contain buffers, diluents and other suitable additives such as, but not limited to, penetration enhancers, carrier compounds and other pharmaceutically acceptable carriers or excipients.
Certain embodiments of the invention provide pharmaceutical compositions containing one or more oligomeric compounds and one or more other chemotherapeutic agents that function by a non-antisense mechanism. Examples of such chemotherapeutic agents include but are not limited to cancer chemotherapeutic drugs such as daunorubicin, daunomycin, dactinomycin, doxorubicin, epirubicin, idarubicin, esorubicin, bleomycin, mafosfamide, ifosfamide, cytosine arabinoside, bischloroethyl-nitrosurea, busulfan, mitomycin C, actinomycin D, mithramycin, prednisone, hydroxyprogesterone, testosterone, tamoxifen, dacarbazine, procarbazine, hexamethylmelamine, pentamethylmelamine, mitoxantrone, amsacrine, chlorambucil, methylcyclohexylnitrosurea, nitrogen mustards, melphalan, cyclophosphamide, 6-mercaptopurine, 6-thioguanine, cytarabine, 5-azacytidine, hydroxyurea, deoxycoformycin, 4-hydroxyperoxycyclo-phosphoramide, 5-fluorouracil (5-FU), 5-fluorodeoxyuridine (5-FUdR), methotrexate (MTX), colchicine, taxol, vincristine, vinblastine, etoposide (VP-16), trimetrexate, irinotecan, topotecan, gemcitabine, teniposide, cisplatin and diethylstilbestrol (DES). When used with the compounds of the invention, such chemotherapeutic agents may be used individually (e.g., 5-FU and oligonucleotide), sequentially (e.g., 5-FU and oligonucleotide for a period of time followed by MTX and oligonucleotide), or in combination with one or more other such chemotherapeutic agents (e.g., 5-FU, MTX and oligonucleotide, or 5-FU, radiotherapy and oligonucleotide). Anti-inflammatory drugs, including but not limited to nonsteroidal anti-inflammatory drugs and corticosteroids, and antiviral drugs, including but not limited to ribivirin, vidarabine, acyclovir and ganciclovir, may also be combined in compositions of the invention. Combinations of antisense compounds and other non-antisense drugs are also within the scope of this invention. Two or more combined compounds may be used together or sequentially.
In another related embodiment, compositions of the invention may contain one or more antisense compounds, particularly oligonucleotides, targeted to a first nucleic acid and one or more additional antisense compounds targeted to a second nucleic acid target. For example, the first target may be a particular antisense sequence of Erythropoietin (EPO), and the second target may be a region from another nucleotide sequence. Alternatively, compositions of the invention may contain two or more antisense compounds targeted to different regions of the same Erythropoietin (EPO) nucleic acid target. Numerous examples of antisense compounds are illustrated herein and others may be selected from among suitable compounds known in the art. Two or more combined compounds may be used together or sequentially.
Dosing:
The formulation of therapeutic compositions and their subsequent administration (dosing) is believed to be within the skill of those in the art. Dosing is dependent on severity and responsiveness of the disease state to be treated, with the course of treatment lasting from several days to several months, or until a cure is effected or a diminution of the disease state is achieved. Optimal dosing schedules can be calculated from measurements of drug accumulation in the body of the patient. Persons of ordinary skill can easily determine optimum dosages, dosing methodologies and repetition rates. Optimum dosages may vary depending on the relative potency of individual oligonucleotides, and can generally be estimated based on EC50s found to be effective in in vitro and in vivo animal models. In general, dosage is from 0.01 μg to 100 g per kg of body weight, and may be given once or more daily, weekly, monthly or yearly, or even once every 2 to 20 years. Persons of ordinary skill in the art can easily estimate repetition rates for dosing based on measured residence times and concentrations of the drug in bodily fluids or tissues. Following successful treatment, it may be desirable to have the patient undergo maintenance therapy to prevent the recurrence of the disease state, wherein the oligonucleotide is administered in maintenance doses, ranging from 0.01 μg to 100 g per kg of body weight, once or more daily, to once every 20 years. Administration of a ribonucleotide reductase antisense oligonucleotide to patients having acute myeloid leukemia in a dose escalation study was described by Klisovic, et al., 2008, “Phase I study of GTI-2040, an antisense to ribonucleotide reductase, in combination with high-dose cytarabine in patients with acute mycloid leukemia,” Clin Cancer Research: 14(12):3889-95, incorporated herein by reference.
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Numerous changes to the disclosed embodiments can be made in accordance with the disclosure herein without departing from the spirit or scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above described embodiments.
All documents mentioned herein are incorporated herein by reference. All publications and patent documents cited in this application are incorporated by reference for all purposes to the same extent as if each individual publication or patent document were so individually denoted. By their citation of various references in this document. Applicants do not admit any particular reference is “prior art” to their invention. Embodiments of inventive compositions and methods are illustrated in the following examples.
EXAMPLES
The following non-limiting Examples serve to illustrate selected embodiments of the invention. It will be appreciated that variations in proportions and alternatives in elements of the components shown will be apparent to those skilled in the art and are within the scope of embodiments of the present invention.
Example 1
Design of Antisense Oligonucleotides Specific for a Nucleic Acid Molecule Antisense to and/or Sense Strand of Erythropoietin (EPO) Polynucleotide
As indicated above the term “oligonucleotide specific for” or “oligonucleotide targets” refers to an oligonucleotide having a sequence (i) capable of forming a stable complex with a portion of the targeted gene, or (ii) capable of forming a stable duplex with a portion of an mRNA transcript of the targeted gene.
Selection of appropriate oligonucleotides is facilitated by using computer programs that automatically align nucleic acid sequences and indicate regions of identity or homology. Such programs are used to compare nucleic acid sequences obtained, for example, by searching databases such as Genbank or by sequencing PCR products. Comparison of nucleic acid sequences from a range of species allows the selection of nucleic acid sequences that display an appropriate degree of identity between species. In the case of genes that have not been sequenced, Southern blots are performed to allow a determination of the degree of identity between genes in target species and other species. By performing Southern blots at varying degrees of stringency, as is well known in the art, it is possible to obtain an approximate measure of identity. These procedures allow the selection of oligonucleotides that exhibit a high degree of complementarity to target nucleic acid sequences in a subject to be controlled and a lower degree of complementarity to corresponding nucleic acid sequences in other species. One skilled in the art will realize that there is considerable latitude in selecting appropriate regions of genes for use in the present invention.
An antisense compound is “specifically hybridizable” when binding of the compound to the target nucleic acid interferes with the normal function of the target nucleic acid to cause a modulation of function and/or activity, and there is a sufficient degree of complementarity to avoid non-specific binding of the antisense compound to non-target nucleic acid sequences under conditions in which specific binding is desired, i.e., under physiological conditions in the case of in vivo assays or therapeutic treatment, and under conditions in which assays are performed in the case of in vitro assays.
The hybridization properties of the oligonucleotides described herein can be determined by one or more in vitro assays as known in the art. For example, the properties of the oligonucleotides described herein can be obtained by determination of binding strength between the target natural antisense and a potential drug molecules using melting curve assay.
The binding strength between the target natural antisense and a potential drug molecule (Molecule) can be estimated using any of the established methods of measuring the strength of intermolecular interactions, for example, a melting curve assay.
Melting curve assay determines the temperature at which a rapid transition from double-stranded to single-stranded conformation occurs for the natural antisense/Molecule complex. This temperature is widely accepted as a reliable measure of the interaction strength between the two molecules.
A melting curve assay can be performed using a cDNA copy of the actual natural antisense RNA molecule or a synthetic DNA or RNA nucleotide corresponding to the binding site of the Molecule. Multiple kits containing all necessary reagents to perform this assay are available (e.g. Applied Biosystems Inc. MeltDoctor kit). These kits include a suitable buffer solution containing one of the double strand DNA (dsDNA) binding dyes (such as ABI HRM dyes, SYBR Green, SYTO, etc.). The properties of the dsDNA dyes are such that they emit almost no fluorescence in free form, but are highly fluorescent when bound to dsDNA.
To perform the assay the cDNA or a corresponding oligonucleotide are mixed with Molecule in concentrations defined by the particular manufacturer's protocols. The mixture is heated to 95° C. to dissociate all pre-formed dsDNA complexes, then slowly cooled to room temperature or other lower temperature defined by the kit manufacturer to allow the DNA molecules to anneal. The newly formed complexes are then slowly heated to 95° C. with simultaneous continuous collection of data on the amount of fluorescence that is produced by the reaction. The fluorescence intensity is inversely proportional to the amounts of dsDNA present in the reaction. The data can be collected using a real time PCR instrument compatible with the kit (e.g. ABI's StepOne Plus Real Time PCR System or LightTyper instrument, Roche Diagnostics, Lewes, UK).
Melting peaks are constructed by plotting the negative derivative of fluorescence with respect to temperature (-d(Fluorescence)/dT) on the y-axis) against temperature (x-axis) using appropriate software (for example LightTyper (Roche) or SDS Dissociation Curve, ABI). The data is analyzed to identify the temperature of the rapid transition from dsDNA complex to single strand molecules. This temperature is called Tm and is directly proportional to the strength of interaction between the two molecules. Typically, Tm will exceed 40° C.
Example 2
Modulation of EPO Polynucleotides
HepG2 cells from ATCC (cat# HB-8065) were grown in growth media (MEM/EBSS (Hyclone cat #SH30024, or Mediatech cat #MT-10-010-CV)+10% FBS (Mediatech cat# MT35-011-CV)+ penicillin/streptomycin (Mediatech cat# MT30-002-C1)) at 37° C. and 5% CO2. One day before the experiment the cells were replated at the density of 1.5×105/ml into 6 well plates and incubated at 37° C. and 5% CO2. On the day of the experiment the media in the 6 well plates was changed to fresh growth media. All antisense oligonucleotides were diluted to the concentration of 20 μM. Two μl of this solution was incubated with 400 μl of Opti-MEM media (Gibco cat#31985-070) and 4 μl of Lipofectamine 2000 (Invitrogen cat#11668019) at room temperature for 20 min and applied to each well of the 6 well plates with HepG2 cells. A similar mixture, which contained 2 μl of water instead of the oligonucleotide solution, was used for the mock-transfected controls. After 3-18 h of incubation at 37° C. and 5% CO2 the media was changed to fresh growth media. 48 h after addition of antisense oligonucleotides the media was removed and RNA was extracted from the cells using SV Total RNA Isolation System from Promega (cat #Z3105) or RNeasy Total RNA Isolation kit from Qiagen (cat#74181) following the manufacturers' instructions. 600 ng of RNA was added to the reverse transcription reaction performed using Verso cDNA kit from Thermo Scientific (cat#AB1453B) or High Capacity cDNA Reverse Transcription Kit (cat#4368813) as described in the manufacturer's protocol. The cDNA from this reverse transcription reaction was used to monitor gene expression by real time PCR using AB Taqman Gene Expression Mix (cat#4369510) and primers/probes designed by ABI (Applied Biosystems Taqman Gene Expression Assay: Hs00171267_ml by Applied Biosystems Inc., Foster City Calif.). The following PCR cycle was used: 50° C. for 2 min, 95° C. for 10 min, 40 cycles of (95° C. for 15 seconds, 60° C. for 1 min) using StepOne Plus Real Time PCR Machine (Applied Biosystems).
Fold change in gene expression after treatment with antisense oligonucleotides was calculated based on the difference in 18S-normalized dCt values between treated and mock-transfected samples.
Primers and probe for the custom designed Taqman assay for the EPO natural antisense EPOAS (SEQ ID NO: 3)









Forward Primer Seq. 



(SEQ ID NO: 10)



ACCACCCCGGTGTCAAG



 



Reverse Primer Seq. 



(SEQ ID NO: 11)



TTTACCTGTTTTCGCACCTACCAT



 



Reporter Seq. 



(SEQ ID NO: 12)



CAAGCTGTGACTTCTC



 



Reporter 1 Dye:



FAM






Results:

Real time PCR results show that the levels of the EPO mRNA in HepG2 cells are significantly increased 48 h after treatment with two of the siRNAs designed to epoas (epoas_1, P=0.02, and epoas_2, P=0.04, FIG. 1A). In the same samples the levels of epoas RNA were possibly decreased after treatment with siRNAs to epoas (FIG. 1B).
Example 3
Modulation of EPO Protein Product In Vitro
HepG2 cells treated with EPO antisense oligonucleotides as described in Example 2 are assayed for EPO protein expression. The human EPO protein concentration and secretion levels present in the cell supernatant are assayed using an enzyme linked immunosorbent assay (ELISA) kit (available commercially, e.g., Quantikine human erythropoictin, R&D Systems. Minneapolis, Minn.), according to the manufacturer's instructions, and compared with levels in the untransfected control samples.
Example 4
Modulation of EPO Polynucleotide and Protein Product in ICGN Mice
Antisense oligonucleotides specific for EPO-AS are administered to ICGN (ICR-derived glomerulonephritis) mice, a genetically anemic mouse model, and the amelioration of anemia monitored. See, e.g., Nagasaki, et al,, 2009, “Amelioration of Anemia in the ICGN Mouse, a Renal Anemia Model, with a Subcutaneous Bolus Injection of Erythropoietin Adsorbed to Hydroxyapatite Matrix,” J. Vet. Med. Sci. 71(10): 1365-1371, incorporated herein by reference. The oligonucleotides are administered at by tail vein injection using a 27G needle. Bolus dosing of the antisense oligonucleotides (SEQ ID NOS: 4, 5 and 6) are dissolved in PBS at a concentration allowing the deliver of the intended dose in 8 μl/g body weight, Mice are kept under an infrared lamp for approximately 3 min prior to dosing to ease injection. Control mice axe administered the same volume of PBS alone.
Pre-treatment blood samples are collected several days before dosing by collecting 4-7 drops from the tail vein.
Blood samples are collected from the postcava under anesthesia with CO2 or ether and used for hematological analyses. EPO mRNA levels are measured by RT-PCR assay as described previously. Enzyme linked immunosorbent assay (ELISA) is performed using a Human EPO ELISA Kit (available from, e.g., Quantikine human erythropoietin, R&D Systems, Minneapolis, Minn., or Stemcell Technologies, Vancouver, BC, Canada) to determine plasma rhEPO concentration. Hematological analyses are performed with an automatic counter (KX-21NV; Sysmex, Kobe, Japan) according to the instruction manual. Reticulocytes are counted in the blood smears on glass slides stained with Brecher's New Methylene Blue Solution and the ratio of reticulocytes is calculated. The number of RBCs, hemoglobin concentration, hematocrit value, and the sustaining rate, which is the ratio of the value on day 21 to that on day 0, are evaluated as the sustained efficacy of hematopoiesis. The mice are sacrificed by excess ether inhalation and their enucleated liver, kidneys, and spleen are weighed. Liver, spleen and subcutaneous tissue are fixed in 10% neutral-buffered formalin, and histopathological analyses are performed after hematoxylin and eosin staining.
Example 5
Modulation of EPO Polynucleotide and Protein Product in Patients with Anemia
Patients having anemia are treated with EPO antisense oligonucleotides. Patients are administered antisense oligonucleotides (SEQ ID NOS: 4, 5 and 6) by IV infusion at a rate of 5 mg/kg one to five times a week. Hemoglobin is measured regularly, e.g., once a week, by a standard spectrophotometric assay. Treatment is adjusted accordingly, depending on the relative change in hemoglobin level observed from week to week. The dosage is reduced as the hemoglobin approaches 12 g/dL or increases by more than 1 g/dL in any 2-week period. (See, e.g., the guidelines for administration of erythropoietin in the package insert for Epogen®, incorporated herein by reference.)
Expression of EPO protein and mRNA are assayed. Human EPO protein concentration and secretion levels are determined using an enzyme linked immunosorbent assay (ELISA) kit (available commercially. e.g., Quantikine human erythropoietin, R&D Systems, Minneapolis, Minn.), according to the manufacturer's instructions. mRNA is assayed using RT-PCR, as described elsewhere herein.
Although the invention has been illustrated and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.
The Abstract of the disclosure will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the following claims.

## Claims

1. A synthetic, modified antisense oligonucleotide of 10 to 30 nucleotides in length having at least one modification or a siRNA oligonucleotide of 19-30 nucleotides in length wherein the at least one modification is selected from: at least one modified sugar moiety; at least one modified internucleotide linkage; at least one modified nucleotide, and combinations thereof; wherein said antisense or siRNA oligonucleotide is at least 95% complementary to and specifically hybridizes to a natural antisense polynucleotide of an Erythropoietin (EPO) gene comprising SEQ ID NO: 3 and upregulates the expression of and/or a function of an Erythropoietin (EPO) gene in vivo or in vitro as compared to a normal control.

2. The oligonucleotide of claim 1, wherein the at least one modification comprises at least one internucleotide linkage selected from the group consisting of: phosphorothioate, alkylphosphonate, phosphorodithioate, alkylphosphonothioate, phosphoramidate, carbamate, carbonate, phosphate triester, acetamidate, carboxymethyl ester, and combinations thereof.

3. The oligonucleotide of claim 1, wherein said oligonucleotide comprises at least one phosphorothioate internucleotide linkage.

4. The oligonucleotide of claim 1, wherein said oligonucleotide comprising a backbone of phosphorothioate internucleotide linkages.

5. The oligonucleotide of claim 1, wherein the oligonucleotide comprises at least one modified nucleotide selected from: a peptide nucleic acid, a locked nucleic acid (LNA), an analogue, a derivative, and combinations thereof.

6. The oligonucleotide of claim 1, wherein the oligonucleotide comprises a modified sugar moiety selected from: a 2′-O-methoxyethyl modified sugar moiety, a 2′-methoxy modified sugar moiety, a 2′-O-alkyl modified sugar moiety, a bicyclic sugar moiety, and combinations thereof.

7. The oligonucleotide of claim 1, wherein the oligonucleotide is of at least about 20 to 30 nucleotides in length and specifically hybridizes to the natural antisense polynucleotide of an Erythropoietin (EPO) polynucleotide.

8. The oligonucleotide of claim 1, wherein the oligonucleotide comprises one of the sequences set forth as SEQ ID NOS: 4 or 5.

9. A composition comprising one or more oligonucleotides according to claim 1 and a pharmaceutically acceptable excipient.

10. The composition of claim 9, wherein the oligonucleotides have at least about 95% sequence identity as compared to any one of the nucleotide sequences set forth as SEQ ID NOS: 4 or 5.

11. The composition of claim 9, wherein the oligonucleotides comprise any of the nucleotide sequences set forth as SEQ ID NOS: 4 or 5.

12. The composition of claim 9, wherein the oligonucleotides set forth as SEQ ID NOS: 4 or 5 comprise one or more modifications or nucleotide substitutions.

13. The composition of claim 12, wherein the one or more modifications or nucleotide substitutions are selected from: phosphorothioate, methylphosphonate, peptide nucleic acid, locked nucleic acid (LNA) molecules, and combinations thereof.