# Patent

## Title
Modified bacteria having improved pharmacokinetics and tumor colonization enhancing antitumor activity

## Abstract

Bacterial strains are provided having at least one of a reduced size, a sialic acid coat, inducibly altered surface antigens, and expression of PD-L1 or CTLA-4 agonists and/or tryptophanase. The bacteria may have improved serum half-life, increased penetration into tumors, increased tumor targeting and increased antitumor activity. The bacteria are useful for delivery of therapeutic agents that treat of neoplastic diseases including solid tumors and lymphomas.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a non-provisional of and claims benefit of priority under 35 U.S.C. §119(e) from U.S. Provisional Patent Application No. 62/052,252, filed Sep. 18, 2014, the entirety of which is expressly incorporated herein by reference.


FIELD OF THE INVENTION
This invention is generally in the field of therapeutic delivery systems utilizing live bacteria for the diagnosis and treatment of neoplastic disease.
BACKGROUND OF THE INVENTION
Citation or identification of any reference herein, or any section of this application shall not be construed as an admission that such reference is available as prior art to the present application. The disclosures of each of these publications and patents are hereby incorporated by reference in their entirety in this application, and shall be treated as if the entirety thereof forms a part of this application. Such references are provided for their disclosure of technologies to enable practice of the present invention, to provide basis for claim language, to make clear applicant's possession of the invention with respect to the various aggregates, combinations, and subcombinations of the respective disclosures or portions thereof (within a particular reference or across multiple references). The citation of references is intended to be part of the disclosure of the invention, and not merely supplementary background information. The incorporation by reference does not extend to teachings which are inconsistent with the invention as expressly described herein, and is evidence of a proper interpretation by persons of ordinary skill in the art of the terms, phrase and concepts discussed herein, without being limiting as the sole interpretation available.
Cancer or neoplastic diseases including solid tumors, lymphomas, leukemias or leukemic bone marrow, is a devastating condition of uncontrolled cell growth, which often has the ability to spread throughout the body (metastases) resulting in death. Tumor-targeted bacteria offer tremendous potential advantages for the treatment of solid tumors, including the targeting from a distant inoculation site and the ability to express therapeutic agents directly within the tumor (Pawelek et al., 1997, Tumor-targeted Salmonella as a novel anticancer agent, Cancer Research 57: 4537-4544; Low et al., 1999, Lipid A mutant salmonella with suppressed virulence and TNF-alpha induction retain tumor-targeting in vivo, Nature Biotechnol. 17: 37-41), each of which is expressly incorporated herein by reference in its entirety.
The primary shortcoming of tumor-targeted bacteria investigated in the human clinical trials (Salmonella strain VNP20009 and its derivative TAPET-CD; Toso et al., 2002, Phase I study of the intravenous administration of attenuated Salmonella typhimurium to patients with metastatic melanoma, J. Clin, Oncol. 20: 142-152; Meir et al., 2001, Phase 1 trial of a live, attenuated Salmonella Typhimurium (VNP20009) administered by direct Intra-tumoral (IT) injection, Proc Am Soc Clin Oncol 20: abstr 1043); Nemunaitis et al., 2003, Pilot trial of genetically modified, attenuated Salmonella expressing the E. coli cytosine deaminase gene in refractory cancer patients, Cancer Gene Therapy 10: 737-744, each of which is expressly incorporated herein by reference in its entirety) was that no significant antitumor activity was observed, even in patients where the bacteria was documented to target the tumor. In addition, an important factor was also that bacterial colonization of tumors, both in the form of the percentage of tumors that were colonized and amount of the bacteria that accumulated within the tumors, was usually lower compared to the preclinical studies using mice. One method of increasing the ability of the bacteria to expand their numbers within tumors is to kill tumor cells by engineering the bacteria to express conventional bacterial toxins (e.g., WO2009/126189, WO03/014380, WO/2005/018332, WO/2008/073148, US 2003/0059400 U.S. Pat. Nos. 7,452,531, 7,354,592, 6,962,696, 6,923,972, 6,863,894, 6,685,935, 6,475,482, 6,447,784, 6,190,657 and 6,080,849, each of which is expressly incorporated herein by reference in its entirety).
Use of secreted proteins in live bacterial vectors has been demonstrated by several authors. Holland et al. (U.S. Pat. No. 5,143,830, expressly incorporated in its entirety herein by reference in its entirety) have illustrated the use of fusions with the C-terminal portion of the hemolysin A (hlyA) gene, a member of the type I secretion system. When co-expressed in the presence of the hemolysin protein secretion channel (hlyBD) and a functional TolC, heterologous fusions are readily secreted from the bacteria. The type I secretion system that has been utilized most widely, and although it is currently considered the best system available, is thought to have limitations for delivery by attenuated bacteria (Hahn and Specht, 2003, FEMS Immunology and Medical Microbiology, 37: 87-98, expressly incorporated herein by reference in its entirety). Those limitations include the amount of protein secreted and the ability of the protein fused to it to interfere with secretion. Improvements of the type I secretion system have been demonstrated by Sugamata and Shiba (2005 Applied and Environmental Micobiology 71: 656-662), expressly incorporated herein by reference in its entirety, using a modified hlyB, and by Gupta and Lee (2008 Biotechnology and Bioengineering, 101: 967-974), expressly incorporated herein by reference in its entirety, by addition of rare codons to the hlyA gene, each of which is expressly incorporated by reference in their entirety herein. Fusion to the gene ClyA (Galen et al., 2004, Infection and Immunity, 72: 7096-7106 and Type III secretion proteins have also been used. Surface display has been used to export proteins outside of the bacteria. For example, fusion of the Lpp protein amino acids 1-9 with the transmembrane region B3-B7 of OmpA has been used for surface display (Samuelson et al., 2002, Display of proteins on bacteria, J. Biotechnology 96: 129-154, expressly incorporated by reference in its entirety). The autotransporter surface display has been described by Berthet et al., WO/2002/070645, expressly incorporated by reference in its entirety. Other heterologous protein secretion systems utilizing the autotransporter family can be modulated to result in either surface display or complete release into the medium (see Henderson et al., 2004, Type V secretion pathway: the autotransporter story, Microbiology and Molecular Biology Reviews 68: 692-744; Jose, 2006 Applied Microbiol. Biotechnol. 69: 607-614; Jose J, Zangen D (2005) Autodisplay of the protease inhibitor aprotinin in Escherichia coli. Biochem Biophys Res Commun 333:218-1226 and Rutherford and Mourez 2006 Microbial Cell Factories 5: 22). For example, Veiga et al. (2003 Journal of Bacteriology 185: 5585-5590 and Klauser et al., 1990 EMBO Journal 9: 1991-1999), each of which is expressly incorporated herein by reference in its entirety, demonstrated hybrid proteins containing the b-autotransporter domain of the immunoglogulin A (IgA) protease of Nisseria gonorrhea. Fusions to flagellar proteins have been demonstrated. The peptide, usually of 15 to 36 amino acids in length, is inserted into the central, hypervariable region of the FliC gene such as that from Salmonella muenchen (Verma et al. 1995 Vaccine 13: 235-24; Wu et al., 1989 Proc. Natl. Acad. Sci. USA 86: 4726-4730; Cuadro et al., 2004 Infect. Immun. 72: 2810-2816; Newton et al., 1995, Res. Microbiol. 146: 203-216, each of which is expressly incorporated by reference in its entirety). Multihybrid FliC insertions of up to 302 amino acids have also been prepared (Tanskanen et al. 2000, Appl. Env. Microbiol. 66: 4152-4156, each of which is expressly incorporated by reference in its entirety). Trimerization of antigens and functional proteins can be achieved using the T4 fibritin foldon trimerization sequence (Wei et al. 2008 J. Virology 82: 6200-6208) and VASP tetramerization domains (Kühnel et al., 2004 PNAS 101: 17027-17032), each of which is expressly incorporated by reference in its entirety. The multimerization domains are used to create, bi-specific, tri-specific, and quatra-specific targeting agents, whereby each individual agent is expressed with a multimerization tag, each of which may have the same or separate targeting peptide, such that following expression, surface display, secretion and/or release, they form multimers with multiple targeting domains. Other secretion systems include C-terminal fusions to the protein YebF (Zhang et al., 2006, Extracellular accumulation of recombinant proteins fused to the carrier protein YebF in Escherichia coli, Nat Biotechnol 24: 100-104, expressly incorporated herein by reference in its entirety), which is commercially available as a kit (pAES40; AthenaES, Baltimore, Md.). Fusions to OmsY and other proteins are also capable of secreting proteins into the medium (Zian et al., 2008, Proteome-Based Identification of Fusion Partner for High-Level Extracellular Production of Recombinant Proteins in Escherichia coli, Biotechnol Bioegineer 101: 587-601), expressly incorporated herein by reference in its entirety. Other secretions systems usable according to the present invention include that of Kotzsch et al. 2011 (A secretory system for bacterial production of high-profile protein targets, Protein Science 20: 597-609) using OmpA, OmpF and OsmY, or those described by Yoon et al., 2010 (Secretory production of recombinant proteins in Escherichia coli, Recent Patents on Biotechnology 4: 23-29; US20067094579B2, WO2009021548A1, EP1402036B1, US20067070989B2, US20080193974A1, US20067052867B2, US20036605697B1, U.S. Pat. No. 5,470,719A, US20070287171A1, US20090011995A1, US20080076157A1, US20067112434B2, US20056919198B1, US026455279B1, US20077291325B2, US20087410788B2, US006083715A, EP1270730A1, US20046673569B1, US016309861B1, US5989868A, US20067056732B2, US20056852512B2, US20056861403B2, EP1407052B1, WO2008089132A2, US5824502A, EP1068339B1, US20080166757A1, US016329172B1, US036596509B1, US20036642027B2, WO2006017929A1, US20036596510B1, US20080280346A1, US20077202059B2, US20080280346A1, US20077202059B2, US20097491528B2, US20080206814A1, US20080166764A1, US20080182295A1, US20080254511A1, US20080206818A1, US20067105327B1, US20040005695A1, U.S. Pat. No. 5,508,192A, EP866132A2, U.S. Pat. No. 6,921,659B2, U.S. Pat. No. 6,828,121B2, US20080064062A1, EP786009B1, US20060270043A1), and Habermann and Ertl (U.S. Pat. No. 7,202,059 Fusion proteins capable of being secreted into a fermentation medium), which uses fusions to hirudin, each of which is expressly incorporated herein by reference in its entirety.
Compositions described in accordance with various embodiments herein include, without limitation, Salmonella enterica serovar Typhimurium (“S. typhimurium”), Salmonella montevideo, Salmonella enterica serovar Typhi (“S. typhi”), Salmonella enterica serovar Paratyphi A, Paratyphi B (“S. paratyphi 13”), Salmonella enterica serovar Paratyphi C (“S. paratyphi C”), Salmonella enterica serovar Hadar (“S. hadar”), Salmonella enterica serovar Enteriditis (“S. enteriditis”), Salmonella enterica serovar Kentucky (“S. kentucky”), Salmonella enterica serovar Infantis (“S. infantis”), Salmonella enterica serovar Pullorum (“S. pullorum”), Salmonella enterica serovar Gallinarum (“S. gallinarum”), Salmonella enterica serovar Muenchen (“S. muenchen”), Salmonella enterica serovar Anaturn (“S. anatum”), Salmonella enterica serovar Dublin (“S. dublin”), Salmonella enterica serovar Derby (“S. derby”), Salmonella enterica serovar Choleraesuis var. kunzendorf (“S. cholerae kunzendorf”), and Salmonella enterica serovar minnesota (S. minnesota). A preferred serotype for the treatment of bone marrow related diseases is S. dublin. 
By way of example, live bacteria in accordance with aspects of the invention include known strains of S. enterica serovar Typhimurium (S. typhimurium) and S. enterica serovar Typhi (S. typhi) which are further modified as provided by various embodiments of the invention. Such Strains include Ty21a, CMV906, CMV908, CMV906-htr, CMV908-htr, Ty800, aroA-/serC-, holavax, M01ZH09, VNP20009. See also, U.S. Pat. No. 6,548,287, and EP 0,973,911, each of which is expressly incorporated herein by reference in its entirety. See also, US 20140256922; 20120108640; 20110318308; 20090215754; 20090169517; 20070298012; 20070110752; 20070004666; 20060115483; 20060104955; 20060089350; 20060025387; 20050267103; 20050249706; 20050112642; 20050009750; 20040229338; 20040219169; 20040058849; 20030143676; 20030113293; 20030031628; 20030022835; 20020151063; 20140220661; 20140212396; 20140186401; 20140178341; 20140155343; 20140093885; 20130330824; 20130295054; 20130209405; 20130130292; 20120164687; 20120142080; 20120128594; 20120093773; 20120020883; 20110275585; 20110111496; 20110111481; 20100239546; 20100189691; 20100136048; 20100135973; 20100135961; 20100092438; 20090300779; 20090180955; 20090175829; 20090123426; 20090053186; 20080311081; 20080124355; 20080038296; 20070110721; 20070104689; 20060083716; 20050026866; 20050008618; 20040202663; 20050255088; 20030109026; 20020026655; 20110223241; 20070009489; 20050036987; 20030170276; 20140148582; 20130345114; 20130287810; 20130164380; 20130164307; 20130078275; 20120225454; 20120177682; 20120148601; 20120144509; 20120083587; 20120021517; 20110274719; 20110268661; 20110165680; 20110091493; 20110027349; 20100172976; 20090317404; 20090220540; 20090123382; 20090117049; 20090117048; 20090117047; 20090068226; 20080249013; 20080206284; 20070202591; 20070191262; 20070134264; 20060127408; 20060057152; 20050118193; 20050069491; 20050064526; 20040234455; 20040202648; 20040054142; 20030170211; 20030059400; 20030036644; 20030009015; 20030008839; 20020176848; 20020102242; 20140205538; 20140112951; 20140086950; 20120244621; 20120189572; 20110104196; 20100233195; 20090208534; 20090136542; 20090028890; 20080260769; 20080187520; 20070031382; 20060140975; 20050214318; 20050214317; 20050112140; 20050112139; 20040266003; 20040115174; 20040009936; 20030153527; 20030125278; 20030045492; U.S. Pat. Nos. 8,828,681; 8,822,194; 8,784,836; 8,771,669; 8,734,779; 8,722,668; 8,715,641; 8,703,153; 8,685,939; 8,663,634; 8,647,642; 8,642,257; 8,623,350; 8,604,178; 8,591,862; 8,586,022; 8,568,707; 8,551,471; 8,524,220; 8,440,207; 8,357,486; 8,343,509; 8,323,959; 8,282,919; 8,241,623; 8,221,769; 8,198,430; 8,137,904; 8,066,987; 8,021,662; 8,008,283; 7,998,461; 7,955,600; 7,939,319; 7,915,218; 7,887,816; 7,842,290; 7,820,184; 7,803,531; 7,790,177; 7,786,288; 7,763,420; 7,754,221; 7,740,835; 7,736,898; 7,718,180; 7,700,104; 7,691,383; 7,687,474; 7,662,398; 7,611,883; 7,611,712; 7,588,771; 7,588,767; 7,514,089; 7,470,667; 7,452,531; 7,404,963; 7,393,525; 7,354,592; 7,344,710; 7,247,296; 7,195,757; 7,125,718; 7,084,105; 7,083,791; 7,015,027; 6,962,696; 6,923,972; 6,916,918; 6,863,894; 6,770,632; 6,685,935; 6,682,729; 6,506,550; 6,500,419; 6,475,482; 6,447,784; 6,207,648; 6,190,657; 6,150,170; 6,080,849; 6,030,624; and 5877159, each of which is expressly incorporated herein by reference in its entirety.
Novel strains are also encompassed that are, for example, attenuated in virulence by mutations in a variety of metabolic and structural genes. The invention therefore may provide a live composition for treating cancer comprising a live attenuated bacterium that is a serovar of Salmonella enterica comprising an attenuating mutation in a genetic locus of the chromosome of said bacterium that attenuates virulence of said bacterium and wherein said attenuating mutation is the Suwwan deletion (Murray et al., 2004. Hot spot for a large deletion in the 18-19 Cs region confers a multiple phenotype in Salmonella enterica serovar Typhimurium strain ATCC 14028. Journal of Bacteriology 186: 8516-8523 (2004), expressly incorporated herein by reference in its entirety) or combinations with other known attenuating mutations. Other attenuating mutation useful in the Salmonella bacterial strains described herein may be in a genetic locus selected from the group consisting of phoP, phoQ, edt, cya, crp, poxA, rpoS, htrA, nuoG, pmi, pabA, pts, damA, pur, purA, purB, purl, purF, zwf, aroA, aroB, aroC, aroD, serC, gua, cadA, rfc, rjb, rfa, ompR, msbB, leucine and arginine, and combinations thereof. Strains of Salmonella deleted in stn are particularly preferred.
The invention also encompasses attenuated gram-positive bacteria. For example, Staphylococcus epidermidis, group B Streptococcus including S. agalaciae, and Listeria species including L. monocytogenes may be employed. It is known to those skilled in the art that variations in molecular biology techniques such as use of gram-positive origins of replication, gram-positive signal sequences and gram-positive promoters and filamentous phage (e.g., phage B5; Chopin et al., 2002 J. Bacteriol. 184: 2030-2033, expressly incorporated herein by reference in its entirety, described further below) may be employed and substituted as needed. Other bacterial strains may also be encompassed, including non-pathogenic bacteria of the gut skin (such as Staphylococcus epidermidis, Proprionibacteria) and other body locations known as the human microbiome (Grice et al., Topographical and temporal diversity of the human skin microbiome, Science 324: 1190-1192; A framework for human microbiome research; The Human Microbiome Project Consortium, 14 June, 2012 Nature 486, 215-221; Spor et al., 2011, Unravelling the effects of the environment and host genotype on the gut microbiome, Nature Reviews Microbiology 9: 279-290, each of which is expressly incorporated herein by reference in its entirety) such as E. coli strains, Bacteriodies, Bifidobacterium and Bacillus, attenuated pathogenic strains of E. coli including enteropathogenic and uropathogenic isolates, Enterococcus sp. and Serratia sp. as well as attenuated Neisseria sp., Shigella sp., Staphylococcus sp., Staphylococcus carnosis, Yersinia sp., Streptococcus sp. and Listeria sp. including L. monocytogenes. Bacteria of low pathogenic potential to humans and other mammals or birds or wild animals, pets and livestock, such as insect pathogenic Xenorhabdus sp., Photorhabdus sp. and human wound Photorhabdus (Xenorhabdus) are also encompassed. Probiotic strains of bacteria are also encompassed, including Lactobacillus sp. (e.g., Lactobacillus acidophilus, Lactobacillus salivarius) Lactococcus sp., (e.g., Lactococcus lactis, Lactococcus casei) Leuconostoc sp., Pediococcus sp., Streptococcus sp. (e.g., S. salivariu, S. thermophilus), Bacillus sp., Bifidobacterium sp., Bacteroides sp., and Escherichia coli such as the 1917 Nissel strain. It is known to those skilled in the art that minor variations in molecular biology techniques such as use of gram-positive origins of replication, gram-positive signal sequences gram-positive promoters (e.g., Lactococcus expression, Mohamadzadeh et al., PNAS Mar. 17, 2009 vol. 106 no. 11 4331-4336, expressly incorporated herein by reference in its entirety) may be used and substituted as needed. The bacteria may be further modified to be internalized into the host cell (Guimaraes et al., 2006, Use of Native Lactococci as Vehicles for Delivery of DNA into Mammalian Epithelial Cells, Appl Environ Microbiol. 2006 November; 72(11): 7091-7097; Innocentin et al., 2009, Lactococcus lactis Expressing either Staphylococcus aureus Fibronectin-Binding Protein A or Listeria monocytogenes Internalin A Can Efficiently Internalize and Deliver DNA in Human Epithelial Cells Appl Environ Microbiol. 2009 July; 75(14): 4870-4878, each of which is expressly incorporated herein by reference in its entirety).
The invention also encompasses combinations with known agents, including imatinib and reticuloendothelial system (RES) blocker such as clodronate (dichloromethylene-bisphosphonate; Compositions and methods comprising genetically enhanced obligate and facultative anaerobic bacteria for oncopathic cancer therapy, WO 2009111177, expressly incorporated herein by reference in its entirety) which have the potential to improve the circulation time of the bacteria, vascular permeability inducing agents such as bradykinin, hyperthermia or carbogen which have the potential to improve the permeability of the tumor enhancing entry of the bacteria, or aldose reductase inhibitors.
The invention also encompasses combinations with protease inhibitors and targeted toxins and chimeric toxins and antitumor enzymes and/or genetically engineered phage and phagemids (Bermudes U.S. Pat. No. 8,524,220, Protease Inhibitor: Protease sensitivity expression system composition and methods improving the therapeutic activity and specificity of proteins delivered by bacteria; U.S. Pat. No. 8,241,623, Protease Sensitivity Expression System; U.S. Pat. No. 8,623,350 Protease inhibitor: protease sensitivity expression system and method improving the therapeutic activity and specificity of proteins and phage and phagemids delivered by bacteria, each of which is expressly incorporated herein by reference in its entirety).
The invention also encompasses combinations with antivascular agents, such as platelet factor 4 and thrombospondin, alone or in combination (Bermudes et al., U56962696, U.S. Pat. No. 7,452,531 Compositions and Methods for Tumor-Targeted Delivery of Effector Molecules, each of which is expressly incorporated herein by reference in its entirety).
The present invention provides, according to various embodiments, live attenuated therapeutic bacterial strains that have improved ability compared to a parental strain in regard to the pharmacokinetic properties of enhanced circulation in the bloodstream and entry into, persistence and growth within tumors, by resisting immune elimination or lytic destruction, increased numbers of foci within tumors, increased colonization, expansion and persistence within tumors. It is the intention of these changes that the result in an overall increase in 1) the percentage of tumors targeted, 2) the number of individual locations (foci) within a tumor that are targeted, 3) the number of CFU/g that are found within the tumor, 4) the length of time that they reside within the tumor and 5) reduced immune clearance from the tumor, and, alone or collectively 6) increased antitumor activity.
SUMMARY AND OBJECTS OF THE INVENTION
3.1 Improved Pharmocokinetics and Tumor Colonization
The present technology provides compositions and methods to enhance bacterial half-life in the bloodstream, passage out of the vasculature into the target tissue, targeting of tumors and lymphomas, colonization of tumors and lymphomas, expansion within tumor or lymphoma and persistence within tumor and lymphomas, each of which, alone or in combination or subcombination, result in an overall increase in 1) the percentage of tumors and lymphomas targeted, 2) the number of individual locations (foci) within a tumor or lymphoma that are established, 3) the number of colony forming units (CFU/g) that are found within the tumor or lymphoma, 4) the length of time that they reside within the tumor or lymphoma and 5) reduced immune clearance from the tumor or lymphoma, and, alone or collectively, 6) increased anticancer activity.
The compositions or genetically engineered bacteria may comprise at least one of
1) one or more mutations that result in smaller sized bacteria (e.g., smaller volume, smaller surface area, small linear dimensions, or smaller mass) with improved (increased) half-life pharmacokinetics in blood and improved penetration though leaky tumor vasculature,
2) bacteria with a protective sialic acid coat that have improved (increased) pharmacokinetics in blood and improved penetration though leaky tumor vasculature and reduced immune clearance,
3) bacteria that alternately express external antigens such as O and H antigens under exogenous control of inducible promoters such that different antigens are expressed at different times and result in bacteria with improved (increased) pharmacokinetics in blood and reduced immune clearance and reduced immune recognition upon repeated dosing,
4) bacteria that deliver ligands against programmed cell death protein 1 ligand (PD-L1) which sequester or block those ligands and result in T-cells attacking tumors and increasing the habitable region of the tumor by bacteria,
5) expression of the E. coli tryptophanase which results in greater tumor cell killing and enhanced penetration of the bacteria within the tumor, and
6) expression of mammalian or bacterial tyrosinase at high (toxic) levels, which e.g., can lead to oxidative stress and metabolic disruption, or prodrug activation.
7) bacteria with resistance to human serum and serum components, which acts as an alternative mechanism to reduced elimination by selection for spontaneously resistant mutants alone or together with CO2 resistance, or expression of serum resistance proteins.
The types of cancers or neoplasias to which the present invention is directed include all neoplastic malignancies, including solid tumors such as those of colon, lung, breast, prostate, sarcomas, carcinomas, head and neck tumors, melanoma, as well as hematological, non-solid or diffuse cancers such as leukemia and lymphomas, myelodysplastic cells, plasma cell myeloma, plasmacytomas, and multiple myelomas. Specific types of cancers include acute lymphoblastic leukemia, acute myeloid leukemia, adrenocortical carcinoma adrenocortical carcinoma, aids-related cancers, aids-related lymphoma, anal cancer, appendix cancer, astrocytomas, childhood, teratoid/rhabdoid tumor, childhood, central nervous system tumors, basal cell carcinoma, bile duct cancer, extrahepatic bladder cancer, bladder cancer, bone cancer, osteosarcoma and malignant fibrous histiocytoma, brain stem glioma, brain tumor, brain stem glioma, central nervous system atypical teratoid/rhabdoid tumor, central nervous system embryonal tumors, brain tumor, astrocytomas, craniopharyngioma, ependymoblastoma, ependymoma, medulloblastoma, medulloepithelioma, pineal parenchymal tumors, supratentorial primitive neuroectodermal tumors and pineoblastoma, spinal cord tumors, breast cancer (female), breast cancer (male), bronchial tumors, burkitt lymphoma, carcinoid tumor, gastrointestinal, nervous system atypical teratoid/rhabdoid tumor, central nervous system embryonal tumors, central nervous system lymphoma, primary cervical cancer, cervical cancer, chordoma, chronic lymphocytic leukemia, chronic myelogenous leukemia, chronic myeloproliferative disorders, colon cancer, colorectal cancer, craniopharyngioma, cutaneous T-cell lymphoma, embryonal tumors, endometrial cancer, ependymoblastoma, ependymoma, esophageal cancer, ewing sarcoma family of tumors, extracranial germ cell tumor, extrahepatic bile duct cancer, eye cancer, intraocular melanoma, eye cancer, retinoblastoma gallbladder cancer, gastric (stomach) cancer, gastrointestinal carcinoid tumor, gastrointestinal stromal tumor (gist), gastrointestinal stromal cell tumor, germ cell tumor, extracranial germ cell tumor, extragonadal germ cell tumor, ovarian gestational trophoblastic tumor, glioma, hairy cell leukemia, head and neck cancer, hepatocellular (liver) cancer, primary hepatocellular (liver) cancer, histiocytosis, langerhans cell, hodgkin lymphoma, hypopharyngeal cancer, intraocular melanoma, islet cell tumors (endocrine pancreas), kaposi sarcoma, kidney (renal cell) cancer, kidney cancer, langerhans cell histiocytosis, laryngeal cancer, leukemia, acute lymphoblastic leukemia, acute myeloid leukemia, chronic lymphocytic leukemia, chronic myelogenous leukemia, hairy cell leukemia, lip and oral cavity cancer, liver cancer, adult (primary) liver cancer, (primary) lung cancer, non-small cell lung cancer, small cell lymphoma, aids-related lymphoma, burkitt lymphoma, cutaneous T-cell lymphoma, hodgkin lymphoma, non-hodgkin lymphoma, primary central nervous system lymphoma, macroglobulinemia, Waldenström malignant fibrous histiocytoma of bone and osteosarcoma, medulloblastoma, melanoma, intraocular (eye) melanoma, merkel cell carcinoma, mesothelioma, metastatic squamous neck cancer with occult primary, mouth cancer, multiple endocrine neoplasia syndrome, childhood multiple myeloma/plasma cell neoplasm, mycosis fungoides, myelodysplastic syndromes, myelodysplastic/myeloproliferative diseases, myelogenous leukemia, chronic myeloid leukemia, adult acute myeloid leukemia, childhood acute myeloma, multiple myeloproliferative disorders, nasal cavity and paranasal sinus cancer, nasopharyngeal cancer, nasopharyngeal cancer, neuroblastoma, non-hodgkin lymphoma, non-small cell lung cancer, oral cancer, oral cavity cancer, lip and oropharyngeal cancer, osteosarcoma and malignant fibrous histiocytoma of bone, ovarian cancer, ovarian epithelial cancer, ovarian germ cell tumor, ovarian low malignant potential tumor, pancreatic cancer, islet cell tumors, papillomatosis, paranasal sinus and nasal cavity cancer, parathyroid cancer, penile cancer, pharyngeal cancer, pineal parenchymal tumors of intermediate differentiation, pineoblastoma and supratentorial primitive neuroectodermal tumors, pituitary tumor, plasma cell neoplasm/multiple myeloma, pleuropulmonary blastoma, primary central nervous system lymphoma, prostate cancer, rectal cancer, renal cell (kidney) cancer, renal pelvis and ureter, transitional cell cancer, respiratory tract carcinoma involving the nut gene on chromosome 15, retinoblastoma, rhabdomyosarcoma, salivary gland cancer, sarcoma, ewing sarcoma family of tumors, kaposi sarcoma, soft tissue sarcoma, uterine sarcoma, Sézary syndrome, skin cancer (nonmelanoma), melanoma, skin carcinoma, merkel cell, small cell lung cancer, small intestine cancer, soft tissue sarcoma, squamous cell carcinoma, see skin cancer (nonmelanoma), squamous neck cancer with occult primary, metastatic stomach (gastric) cancer, stomach (gastric) cancer, supratentorial primitive neuroectodermal tumors, T-cell lymphoma, cutaneous T-cell lymphoma, mycosis fungoides and Sézary syndrome, testicular cancer, throat cancer, thymoma and thymic carcinoma, thyroid cancer, transitional cell cancer of the renal pelvis and ureter, trophoblastic tumor, (gestational), unknown primary site, carcinoma of, unknown primary site carcinoma, ureter and renal pelvis, transitional cell cancer, urethral cancer, uterine cancer, endometrial uterine sarcoma, vaginal cancer, vulvar cancer, Waldenström macroglobulinemia, and Wilms tumor.
Issues related to bacterial targeting and efficacy have previously been address by Bermudes (Protease sensitivity expression system, U.S. Pat. No. 8,241,623 B1, incorporated by reference in its entirety in this application, and shall be treated as if the entirety thereof forms a part of this application). Survival under CO2 conditions, high osmolarity and acidic conditions has also been addressed (Bermudes U.S. Pat. No. 8,647,642, (Live bacterial vaccines resistant to carbon dioxide (CO2), acidic PH and/or osmolarity for viral infection prophylaxis or treatment), expressly incorporated by reference in its entirety.
As cited above, the primary shortcoming of tumor-targeted bacteria investigated in the human clinical trials (Salmonella strain VNP20009 and its derivative TAPET-CD; Toso et al., 2002, Phase I study of the intravenous administration of attenuated Salmonella typhimurium to patients with metastatic melanoma, J. Clin, Oncol. 20: 142-152; Meir et al., 2001, Phase 1 trial of a live, attenuated Salmonella Typhimurium (VNP20009) administered by direct Intra-tumoral (IT) injection, Proc Am Soc Clin Oncol 20: abstr 1043; Nemunaitis et al., 2003, Pilot trial of genetically modified, attenuated Salmonella expressing the E. coli cytosine deaminase gene in refractory cancer patients, Cancer Gene Therapy 10: 737-744, each of which is expressly incorporated herein by reference in its entirety) is that no antitumor activity was observed, even in patients that were documented to have had tumors that were colonized by the bacteria. An additional divergence between the murine studies (e.g., Pawelek et al., 1997, Tumor-targeted Salmonella as a novel anticancer agent, Cancer Research 57: 4537-4544; Low et al., 1999, Lipid A mutant salmonella with suppressed virulence and TNF-alpha induction retain tumor-targeting in vivo, Nature Biotechnol. 17: 37-41, each of which is expressly incorporated herein by reference in its entirety), is that in most patients, the levels of the bacteria were significantly lower. For example, whereas in the murine models the bacteria frequently achieved levels of 1×109 colony forming units (CFU) per gram of tumor tissue, in humans the levels were significantly lower, e.g., 1×106 CFU/g was achieved in 3 patients (Meir et al., 2001). Generally, it has been perceived that the murine studies should precede using bacteria with the greatest amount of tumor targeting. For example, Pawelek et al., WO/1996/040238, expressly incorporated herein by reference in its entirety, selected “super infective” bacteria by cycling through tumors. The novel cycling and selection procedure they employed selected for increased targeting numbers which was correlated with a greater antitumor effect. A similar study using the strain AR-1 was performed by Zhao et al., 2005 (Tumor-targeting bacterial therapy with amino acid auxotrophs of GFP-expressing Salmonella typhimurium) Proc Natl Acad Sci USA. 102: 755-760, expressly incorporated herein by reference in its entirety). In the development of the Salmonella strain A1-R by re-isolation form a tumor, as described by the same group in a later study (Hayashi et al., 2009, Cancer metastasis directly eradicated by targeted therapy with a modified Salmonella typhimurium, Journal of Cellular Biochemistry 106: 992-998, expressly incorporated herein by reference in its entirety) “The idea was to increase the tumor targeting capability of the bacteria.” Thus, developing and testing bacteria with enhanced tumor targeting using known genetic backgrounds that already exhibit high levels of tumor targeting has been a focus within the field. However, while it is desirable to find ways to improve the levels of bacteria within tumors, including the present technology, the importance of selecting an appropriate tumor model and/or bacterial genetic background to assess the contribution that an effector system might have in a human, or how it might improve tumor colonization levels, wherein the tumor model and/or bacterial genetic background should provide low (rather than high) levels of tumor colonization, has not been appreciated. It has not been understood that to evaluate how an effector system such as the herpes simplex thymidine kinase or cytosine deaminase described by Pawelek et al., WO/1996/040238, expressly incorporated herein by reference in its entirety, or those provided in the present invention, would function in humans where lower targeting numbers might be expected (at least at the outset; greater number could be achieved if the effector system is effective), such that the murine tumor system and/or bacterial genetic background where the tumor-targeting level is similar to the level achieved in humans represents an appropriate model.
firA is a mutation within the gene that encodes the enzyme UDP-3-O (R-30 hydroxymyristoyl)-glycocyamine N-acyltransferase, that regulates the third step in endotoxin biosynthesis (Kelley et al., 1993, J, Biol. Chem. 268:19866-19874, expressly incorporated herein by reference in its entirety). Salmonella typhimurium and E. coli strains bearing this type of mutation produce a lipid A that differs from wild type lipid A in that it contains a seventh fatty acid, a hexadecanoic acid (Roy and Coleman, 1994, J. Bacteriol. 176:16394646, expressly incorporated herein by reference in its entirety). Roy and Coleman demonstrated that in addition to blocking the third step in endotoxin biosynthesis, the firA′ mutation also decreases enzymatic activity of lipid A 4′ kinase that regulates the sixth step of lipid A biosynthesis. Salmonella typhimurium strain SH5014 and its firA′ derivative SH7622 are described in Hirvas et al, 1991, EMBO J. 10:1017-1.023, expressly incorporated herein by reference in its entirety. The genotypes of these strains are as follows: strain SH5014 ilv-1178 thr-914 {acute over (η)}is-6116 metA22 metE551 trpB2 xyl-404 HI-b H2-e, n, x flaA66 rpsL120 rfaJ4041; strain SH7622 ilv-1178 thr-914 his-6116 metA22 metE551 trpB2 xyl-404 H1-b H2-e, n, x flahββ rpsL120 rfaJ4041, ssc-1 (firAts). A derivative of Salmonella typhimurium firA′ strain SH7622 was picked, designated SH7622-64, and used as the firA′ strain for the experiments. SH7622-64 was selected for its supersensitivity to the antibiotic novobiocin and temperature-sensitive growth, characteristics of the firA′ SH7622 strain. When studies in two different tumor models, Pawelek et al, found Salmonella/g tissue: Primary Tumor of M27 lung cancer, 2.9×106 per gram and in B16 melanoma, 3.2×105 per gram, yet retaining a similar 3200:1 tumor to liver targeting ratio. This strain, while never used in any subsequent studies, represents a surprising solution to translating murine to human studies wherein both systems tend to have the same number of bacteria per gram of target tissue.
In an alternative approach to selecting bacterial mutants using strain backgrounds with high tumor-targeting and antitumor effects as is commonly applied (Zhao et al., 2005, Tumor-targeting bacterial therapy with amino acid auxotrophs of GFP-expressing Salmonella typhimurium. Proc Natl Acad Sci USA. 102: 755-760, expressly incorporated herein by reference in its entirety), bacterial mutants with suboptimal targeting or low antitumor effects are used for selection of improved antitumor effects. The bacterial mutants can be generated by any standard method of mutation (e.g., UV, nitrosoguanadine, Tn10, Tn5), or can be a spontaneous mutation such as a suppressor mutation (e.g., Murray et al., 2001, Extragenic suppressors of growth defects in msbB Salmonella, J. Bacteriol. 183: 5554-5561, expressly incorporated herein by reference in its entirety), or those of the present invention.
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The present technology provides, according to various embodiments, live attenuated therapeutic bacterial strains that have improved ability compared to a parental strain in regard to the pharmacokinetic properties of enhanced circulation in the bloodstream and entry into, persistence and growth within tumors, by resisting immune elimination or lytic destruction, increased numbers of foci within tumors, increased colonization, expansion and persistence within tumors. It is the intention of these changes that the result in an overall increase in 1) the percentage of tumors targeted, 2) the number of individual locations (foci) within a tumor that are targeted, 3) the number of CFU/g that are found within the tumor, 4) the length of time that they reside within the tumor and 5) reduced immune clearance from the tumor, and, alone or collectively 6) increased antitumor activity.
One object is to select for one or more mutations that result in smaller sized bacteria with improved (increased) pharmacokinetics in blood through reduced elimination and improved penetration though the leaky tumor vasculature.
The present technology also has the objective of utilizing the enhanced permeability and retention (EPR) factor associated with tumor vasculature. To utilize the EPR effect, the bacteria should preferably be smaller than 650 nm in size, and more preferably less than 400 nm in size (Danhier et al., 2010, To exploit the tumor microenvironment: passive and active tumor targeting of nanocarriers for anticancer drug delivery. J. Control. Release 148: 135-146, expressly incorporated herein by reference in its entirety). Preferred bacteria therefore have as their width less than 650 nm, and more preferably less than 400 nm.
Another object is to generate bacteria with a protective sialic acid coat that results in improved (increased) pharmacokinetic half-life in blood, improved penetration though leaky tumor vasculature and reduced immune clearance. The non-limiting mechanisms by which sialic acid prevents immune clearance include reduced opsonization (i.e., reduced interaction with complement, ficolin, manose binding protein, C-reactive protein, scavenger receptor, and/or antibodies) by increasing repulsive interaction with blood components and increasing surface hydrophobicty. The present invention is unlike vaccine vectors that express glycosylated antigens (Szymanski and Nothaft EP2611823, Peptide containing multiple n-linked glycosylation sequons, expressly incorporated herein by reference in its entirety) because the invention is directed toward reduced immune stimulation, detection or elimination, whereas vaccine vectors are designed to be detected and to stimulate the immune system.
Another object is to construct bacteria that alternately express external antigens such as 0 and H antigens under exogenous control of inducible promoters such that different antigens are controllably expressed at different times and result in bacteria with improved (increased) pharmacokinetics in blood and reduced immune clearance and reduce immune recognition upon repeated dosing.
Another object is to develop bacteria that deliver ligands against programmed cell death protein 1 (PD1) and/or its ligand (PD-L1 and PD-L2) or CTLA-4 which has the result of increased T-cells attacking tumors and increasing the habitable region of the tumor by bacteria through their killing of tumor cells and providing nutrients for the bacteria. Compositions and methods for inhibition of PD-1 or PD-L1/PD-L2 have been described by U.S. Pat. No. 6,803,192, US 20130202623 and PCT publication No. WO 10/027423 each of which is expressly incorporated by reference in its entirety
Another object is to genetically modify the bacteria to express the E. coli tryptophanase which results in greater tumor cell killing and enhanced penetration of the bacteria within the tumor.
Another object is to genetically modify the bacteria to express and secrete mammalian or bacterial tyrosinase, as directly toxic principle or as a prodrug-converting enzyme. More broadly, other known prodrug converting enzymes secretable from the bacteria (e.g., Salmonella) may be employed, such as cytosine deaminase. Similarly, essential biochemical depleting enzymes may also be expressed, such as asparginase.
Another object is to increase serum resistance to components that act as opsonins which enhance elimination by phagocytic cells or directly interfere with or kill bacteria, including complement, antibodies, ficolin, scavenger receptor, C-reactive protein (CRP), the bactericidal/permeability-increasing protein (BPI) and mannose binding protein, by reducing their binding or prevention of their mode of action including resisting lytic destruction. The bacteria are selected for as previously described by Pawelek et al., WO/1996/040238, expressly incorporated herein by reference in its entirety, where the bacteria are recycled through tumors. The bacteria are further cycled one or more times through the blood (for selection of increased serum half-life and survival by selecting for their presence at extended times) and through the liver (for selection of increased survival against serum components and/or carbon dioxide (CO2), bicarbonate (HCO3−), carbonate (CO32−) and/or carbonic acid (H2CO3 or OC(OH)2). The vertebrates useful for cycling include mice, rats, guinea pigs, rabbits, dogs, cats, pigs, monkeys and humans. The subjects may be further exposed to carbogen (carbon dioxide and oxygen mixtures) during the selection. The selection may also take place ex vivo (i.e., blood drawn from a patient, or blood fed into a chemostat).
A further object provides a genetically engineered bacterium, optionally being genetically selected or mutated to have a reduced size compared to its parental strain, comprising at least one gene which causes or induces carbohydrate decoration of external components of the genetically engineered bacterium, being adapted for efficacious treatment of a neoplastic disease in the human or animal under non-lethal conditions.
The at least one gene may comprises at least one heterologous gene that produces sialic acids on an external surface of the bacterium.
The genetically engineered bacterium may further comprise inducible gene promoters adapted to control the genetically engineered bacterium to display heterologous surface antigens. The inducible surface antigens may be O-oligosaccharide antigens and/or flagellar (H) antigens.
The genetically engineered bacterium may comprise genetic modifications for producing a plurality of heterologous surface antigens on the genetically engineered bacterium, which are produced by the genetically engineered bacterium under control of multiple different inducible promoters.
The genetically engineered bacterium may comprise genetic modifications for producing a plurality of different heterologous surface antigens on a surface of the genetically engineered bacterium, which are all under control of an acetylsalicylic acid inducible promoter.
The parental strain comprises a bacterium of genus Salmonella, e.g., VNP 20009/YS1646.
The genetically engineered bacterium may be selected or mutated to grow to a maximum size of about 650 nm.
The neoplastic disease comprises may be disease associated with formation of a solid tumor in a host animal, e.g., having necrotic regions.
Administration of the genetically engineered bacterium to the human or animal may result in at least one of: increased numbers of colony forming units within the solid tumor compared to its parental strain; increased serum half-life compared to its parental strain; increased numbers of colony forming units within the solid tumor compared to its parental strain; and reduced immune elimination following repeated dosing compared to its parental strain.
The live genetically engineered bacterium may be provided in a pharmaceutically acceptable formulation suitable for administration to a human or animal, and the carbohydrate decoration of external components of the genetically engineered bacterium is effective for increasing a serum half-life of the live genetically engineered bacterium after administration to the human or animal in the pharmaceutically acceptable formulation.
It is also an object to provide a bacterium genetically engineered to provide an acetylsalicylic acid inducible promoter, which promotes expression of at least one antitumor protein by the bacterium. The bacterium may also have at least one gene which is heterologous, selected or mutated, optionally responsive to an acetyl salicylic acid inducible promoter or the same promoter as the at least one antitumor protein, which causes the bacterium to be decorated with carbohydrates in a heterologous decoration pattern. The at least one gene may comprise a plurality of genes, each responsive to an acetyl salicylic acid inducible promoter, effective for causing the bacterium to selectively display a different heterologous antigen in response to presence of acetyl salicylic acid.
The bacterium may comprise at least one gene which is heterologous, selected or mutated, which causes the bacterium to be decorated with carbohydrates in a heterologous decoration pattern.
A still further object provides a method for treating a neoplastic disease in a living human or animal, comprising: administering a pharmaceutically acceptable formulation containing a genetically engineered bacterium to the living human or animal having the neoplastic disease, the genetically engineered bacterium may optionally be genetically engineered or selected to have a reduced size compared to its parental strain and which grows to a maximum size of about 650 nm, having at least one gene which causes or induces carbohydrate decoration of external components of the genetically engineered bacterium in a pattern different from the parental strain; permitting the genetically engineered bacterium to grow within and then be cleared from the living human or animal to cause antitumor effects, which are non-lethal to the living human or animal.
Administration of the pharmaceutically acceptable formulation containing a genetically engineered bacterium to the human or animal may result in at least one of: increased numbers of colony forming units within the solid tumor compared to its parental strain; increased serum half-life compared to its parental strain; increased numbers of colony forming units within the solid tumor compared to its parental strain; and reduced immune elimination following repeated dosing compared to its parental strain.
The at least one gene may comprise at least one heterologous gene that produces sialic acids on an external surface of the bacterium.
The genetically engineered bacterium may further comprise inducible gene promoters adapted to control the genetically engineered bacterium to display at least one of heterologous 0-oligosaccharide surface antigens and flagellar (H) antigens, further comprising inducing the inducible gene promoters.
Another object provides a live genetically engineered bacterium, comprising: at least one heterologous inducible gene which causes or induces carbohydrate decoration of external components of the live genetically engineered bacterium, at least one gene producing a functional gene product under control of an indicible promoter distinct from the at least one heterologous inducible gene, the live genetically engineered bacterium being adapted for administration to a human or animal and colonization of at least one tissue under non-lethal conditions.
The carbohydrate decoration may comprise sialic acid, O-oligosaccharide antigens, and/or H flagellar antigens, for example.
The gene product may comprise an enzyme which is secreted from the live genetically engineered bacterium in active form, such as an amino-acid degrading enzyme (e.g., tryptophanase, asparaginase) which is secreted from the live genetically engineered bacterium in active form and has anti-tumor activity against humanb or animal tumors colonized by the live genetically engineered bacterium.
The inducible promoter may comprise MarA, which is induced by presence of acetyl salicylic acid. The inducible promoter mauy also be responsive to at least one of tet, arabinose, hypoxia, a cellular SOS response promoter, X-rays, and mitomycin.
The at least one heterologous inducible gene which causes or induces carbohydrate decoration of external components of the genetically engineered bacterium may comprise a plurality of inducible genes having respectively different inducers. At least one of the plurality of inducible genes having respectively different inducers may be responsive to a pharmacological inducer which is not naturally found in human tissue. Tthe at least one heterologous inducible gene and the at least one gene producing a gene product under control of an indicible promoter may each induced by a common inducer. The at least one heterologous inducible gene may comprise a plurality of inducible genes, having respectively different inducible promoters induced by different pharmacological agents not naturally found in humans, to thereby provide the live genetically engineered bacterium having a plurality of different surface antigen patterns under control of a selective presence of the different pharmacological agents.
The live genetically engineered bacterium may have a selective tropism for at least one type of tumor in a human or animal, and the functional gene product is effective for treating the at least one type of tumor, the live genetically engineered bacterium being provided within a pharmaceutically acceptable formulation for administration to the human or animal.
The genetically engineered bacterium may further comprise a heterologous acetyl salicylic acid inducible gene promoter adapted to control the genetically engineered bacterium to produce a gene product, further comprising administering acetylsalycilic acid to the human or animal to induce the gene product.
When administering self-replicating organisms, the minimum dose approximates a single in vivo replication competent organism or minimum infectious dose, which itself is approximated by an in vitro determined colony forming unit (CFU). Suitable dosage ranges are generally from about 1.0 c.f.u./kg to about 1×1010 c.f.u./kg; optionally from about 1.0 c.f.u./kg to about 1×108 c.f.u./kg; optionally from about 1×102 c.f.u./kg to about 1×108 c.f.u./kg; optionally from about 1×104 c.f.u./kg to about 1×108 c.f.u./kg; and optionally from about 1×104 c.f.u./kg to about 1×1010 c.f.u./kg. Effective doses may be extrapolated from dose-response curves derived from in vitro or animal model test systems. However, higher doses are preferred, in order to permit prompt initiation of therapeutic effect and avoid host immune response suppression of the organisms before they reach full therapeutic potential. In some cases, replication incompetent organisms may be used, e.g., where the organisms remain competent to produce biologically active products as discussed herein while not being able to replicate, in which case a dose may be, for example, in the range 108 to 1010 organisms and determined by non-culture based methods (e.g., hemocytometer). The maximum dose of preferred organisms which display low toxicity and pathogenicity is in excess of 1010, and for orally or dermally administered probiotic species, gram scale doses may be administered.
The bacterial delivery vector may be attenuated, non-pathogenic, low pathogenic (including wild type), or a probiotic bacterium. The bacteria are introduced either systemically (e.g., parenteral, intravenous (IV), intramuscular (IM), intralymphatic (IL), intradermal (ID), subcutaneously (sub-q), local-regionally (e.g., intralesionally, intratumorally (IT), intraperitoneally (IP), topically, intathecally (intrathecal), by inhaler or nasal spray) or to the mucosal system through oral, nasal, pulmonary intravessically, enema or suppository administration. The terms “oral”, “enteral”, “enterally”, “orally”, “non-parenteral”, “non-parenterally”, and the like, refer to administration of a compound or composition to an individual by a route or mode along the alimentary canal. Examples of “oral” routes of administration include, without limitation, swallowing liquid or solid forms by the mouth, administration of a composition through a nasojejunal or gastrostomy tube, intraduodenal administration of a composition, and rectal administration, e.g., using suppositories that release a live bacterial strain described herein to the lower intestinal tract of the alimentary canal. Upon administration, the bacteria are able to undergo limited or unlimited replication, express, surface display, secrete and/or release the effector molecules and/or protease inhibitors with anti-cancer thereby providing a therapeutic benefit by reducing or eliminating the malignancy and/or neoplasia.
Bacteria of the invention have recognizable attributes in regard to their serum half-life and presence within tumors. For example, Toso et al., 2002 (Phase I Study of the Intravenous Administration of Attenuated Salmonella typhimurium to Patients with Metastatic Melanoma, Journal of Clinical Oncology, 20: 142-152, expressly incorporated herein by reference in its entirety) showed for example that a dose of 3×108 of the strain VNP20009 resulted in an average (in 6 patients) of approx. 65,000 CFU per ml of blood at 25 min, but only an average of 19 CFU/ml at 60 min., and only an average of 0.1 CFU/ml at 4 hrs, and only one patient in 6 had any CFU/ml at 12 hrs. Bacteria of the invention have significantly higher numbers of colony forming units at one or more times following 25 min, or have higher numbers of patients with greater than 0 CFU/ml at 12 hrs. A single patient in that treatment group received a second dose: that patient had 19,400 CFU/ml at 25 min for the first dose, but only 38 CFU/ml for the second dose. Bacteria of the invention have significantly greater numbers of CFU/ml at 25 min upon subsequent doses. Patients in that same treatment group were also assessed for the presence of CFU/g of tumor tissue. Only one in six patients had any CFU/g in their tumor. Bacteria of the invention have significantly greater percentages of tumors colonized by bacteria. The one tumor that was colonized by the bacteria had 11,000 CFU/g of tumor tissue, compared to 109 CFU/g in tumor tissue of mice (Luo et al., 2001, Antitumor effect of VNP20009, an attenuated Salmonella in murine tumor models. Oncol. Res. 12: 501-508, expressly incorporated herein by reference in its entirety). Bacteria of the invention have significantly CFU/g of tumor tissue. In the study by Toso et al., 2002, no antitumor activity was observed, whereas the bacteria of the invention have improved antitumor activity.



BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1C show schematically a method for selection of bacteria with reduced size.
FIGS. 2A-2C show bacteria with a protective sialic acid coat.
FIGS. 3A-3C show bacteria with inducible expression of alternate surface antigens, and the Mar regulon for use as an inducible promoter.
FIG. 4 shows bacteria delivering ligands against PD-1 ligand (PDL-1).
FIG. 5 shows bacteria that express the E. coli tryptophanase.



DETAILED DESCRIPTION OF THE INVENTION
The present invention provides, according to various embodiments, bacteria with enhanced pharmacokinetics that have improved ability to distribute systemically, to persist longer within tumors, target tumors in multiple foci, targeted higher percentages of tumors, target tumors with increased numbers of bacteria, remove tumor cell immunosuppressive functions, increase the antitumor immune response and have enhanced tumor cell killing that alone or in combination, and result in increased antitumor activity.
For reasons of clarity, the detailed description is divided into the following subsections: 1) bacteria with reduced size, 2) bacteria with a protective sialic acid coat, 3) bacteria that alternately express external antigens such as O and H antigens under exogenous control of inducible promoters, 4) bacteria that deliver anti-immunosuppressive ligands against CTLA-4, programmed cell death protein 1 (PD1) and programmed cell death ligand (PD-L1) and 5) bacteria that express tryptophanase.
The present technology provides, according to various embodiments, improved live attenuated therapeutic bacterial strains that express one or more therapeutic molecules. The primary characteristic of the bacteria of certain embodiments of the invention is the improved targeting to tumors and reduced clearance from the blood (increased serum half-life) with enhanced antitumor activity. In one embodiment, the percent increase in effect is approximately 2% to approximately 95%, approximately 2% to approximately 75%, approximately 2% to approximately 50%, approximately 2% to about 40%, approximately 2% to about 30%, approximately 2% to about 25%, approximately 2% to about 20% or about 2% to approximately 10% greater than the parental strain of bacteria without expressing one or more of the modifications described herein under the same conditions.
5.1. Bacteria with Reduced Size.
Typical Salmonella are gram-negative rods 0.7-1.5 by 2.0-5.0 μm. Salmonella of the invention having smaller size are derived by several different means. Bacteria with smaller size are selected for their ability to pass thorough microporous sterilizing membranes followed by light and electron microscopic analysis. Because of their size, Salmonella do not typically pass through 0.65, 0.45 or 0.22 uM porous filters. The bacteria are thus selected for their ability to pass through successively smaller pore sizes. The present technology and methods may be used alone or in combination and with or without the FabH mutation known to reduce bacterial size (Wootton, 2012, Nature Rev. Microbiol. 10: 670-671, expressly incorporated herein by reference in its entirety). The bacteria may be further cycled through tumors as described by Pawelek et al. (U.S. Pat. No. 6,190,657 Vectors for the Diagnosis and Treatment of Solid Tumors Including Melanoma), expressly incorporated herein by reference in its entirety.
5.1.1. Bacterial Mutations.
Bacteria may be isolated by random mutagenesis using UV and nitrosoguanidine, or by transposon mutagenisis and selected for smaller size as described above. Alternatively, unsuppressed msbB strains (YS1; Murray et al., 2001, Extragenic suppressors of msbB− growth defects in Salmonella. J. Bacteriol. 183: 5554-5561) or partially suppressed msbB strains (Murray et al., 2007. PmrA(Con) Confers pmrHFIJKL-Dependent EGTA and Polymyxin Resistance on msbB Salmonella by Decorating Lipid A with Phosphoethanolamine. J. Bacteriology, 189: 5161-5169; Murray et. al., 2004 Hot spot for a large deletion in the 18-19 Cs region confers a multiple phenotype in Salmonella enterica serovar Typhimurium strain ATCC 14028, J. Bacteriol, 186: 8516-8523, each of which is expressly incorporated herein by reference in its entirety) may be used to selected for spontaneous mutations or combination of selections thereof. The mutations can be identified by methods known to those skilled in the arts including genome sequencing.
5.1.2. Bacteria with Reduced Genome Size.
Bacteria with reduced genomes are generated by selecting for loss of functions that are associated with phenotypic markers. Methods are known to those skilled in the arts (Posfai et al., 2006, Emergent properties of reduced-genome Escherichia coli, Science 312: 1044-1046; Campbell et al., U.S. Pat. No. 8,178,339, Reduced genome E. coli, each of which is expressly incorporated herein by reference in its entirety) and selected for smaller size as described above.
5.1.3. Bacteria with Tighter Genome Packaging.
Bacteria with tighter genome packaging are produced by, e.g.,

    
    
        1) introducing the Chlamydia specific histone-like protein binding sequences
    
    












AATAGGGTTTCTTTTAATAGAAAC
SEQ ID NO: 001






and











AATAGGGATTCCAGTAACAACAAG
SEQ ID NO: 002






    
    
        into the chromosome using methods known to those skilled in the art (e.g., transposons, sucrose vector insertions, lambda red vector insertions) and heterologously expressing the Chlamydia (e.g., Genbank: CP002679.1) histone H1-I, histone-like proteins HC1 and HC2 or homologs or variants thereof (e.g., GenBank: L10193.1 Hc2 nucleoproteins hctB) using methods known to those skilled in the arts, and selecting for smaller size as described above.
    
    


5.2. Bacteria with a Protective Sialic Acid Coat.
The bacteria are engineered to be coated with sialic acid either by A) de novo synthesis or B) scavenged from the host. De novo synthesis of lipopollysaccharide with sialic acid is accomplished by heterologous expression of the genes necessary including but not limited to NeuA, NeuB, NeuC, SiaB, Lic3A, Lic3B, and SOAT (sialic acid O-acyltransferase) as described by Severi et al., 2007 (Sialic acid utilization by bacterial pathogens, Microbiology 153: 2817-2822). De novo synthesis of a polysaccharide capsule with sialic acid is accomplished by the additional heterologous expression of NeuD, NeuS, NeuO, and Kps (capsule export system). Scavenging of sialic acid requires the additional presence of a sialidase, NanC, porins, SatABCD, SiaPQM and NanT. Heterologous expression is achieved using synthetic biology and methods known to those skilled in the art.
5.3. Bacteria that Alternately Express Surface Antigens Such as O and H Antigens Under Exogenous Control of Inducible Promoters.
The diverse range of Salmonella serotypes contains a variety of O-polysaccharide (O-antigen) and flagellar (H antigens) (Grimont, P. A. D & Weill, F. X. 2007. Antigenic Formulae of the Salmonella Serovars, WHO Collaborating Centre for Reference and Research on Salmonella, 9th edition). Exposure of the host to these antigens may lead to protective immunity. In the context of bacterial vectors, protective immunity may either eliminate the vector thereby reducing its antitumor effect or prevent secondary and tertiary dosing. The present technology provides a single bacterium that inducibly undergoes alternate expression of O and H antigens, alone or in simultaneous combination. Methods for deriving heterologous O-antigens have been described by Favre et al., WO/1997/014782, and Roland WO/2000/004919, each of which is expressly incorporated herein by reference in its entirety. O-antigen synthesis is directed by the rfb gene cluster which encodes enzymes involved in biosynthesis of the monomer sugar unit, and the rfc gene, which encodes the O-antigen polymerase responsible for the polymerization of the sugar unit into a high molecular weight polysaccharide chain (Sugiyama et al., 1991 Expression of the Cloned Escherichia coli 09 rfb Gene in Various Mutant Strains of Salmonella typhimurium, J. Bacteriol. 173:55-58; Collins et al. 1991, Molecular Cloning, Characterization, and Nucleotide Sequence of the rfc Gene, Which Encodes an O-Antigen Polymerase of Salmonella typhimurium, J. Bacteriol. 173:2521-2529, each of which is expressly incorporated herein by reference in its entirety). The antigens are chosen such that alternate expression does not have overlap. For example the O-antigens of the S. typhimurium serovar are O: 1, 4, 5, 12, whereas those of S. Montevideo, O: 6, 7, and those of E3 group are O:3,15,34. The genes may be part of a single synthetic operon (polycistronic), or may be separate, monocystronic constructs, with separate individual promoters of the same type used to drive the expression of their respective genes. The promoters may also be of different types, with different genes expressed by different constitutive or f promoters. Use of two separate inducible promoter for more than one antigen allows, when sufficient X-ray, tetracycline, arabinose methylalicylate or other inducer is administered following administration of the bacterial vector, their expression to occur simultaneously, sequentially, or alternating (repeated). A variety of inducible promoters are known including arabinose, (EP1,655,370 A1, expressly incorporated by reference in its entirety), tetracycline inducible promoter (TET promoter), SOS-response promoters responsive to DNA damaging agents such as mitomycin, alkylating agents, X-rays and ultraviolet (UV) light such as the recA promoter, colicin promoters, sulA promoters and hypoxic-inducible promoters including but not limited to the PepT promoter (Bermudes et al., WO 01/25397, expressly incorporated herein by reference in its entirety), the arabinose inducible promoter (AraBAD) (Lossner et al., 2007, Cell Microbiol. 9: 1529-1537; WO/2006/048344) the methylsalicylate inducible promoter (Royo et al., 2007, Nature Methods 4: 937-942; WO/2005/054477, each of which is expressly incorporated herein by reference in its entirety). A single promoter may be used to drive the expression of more than one antigen gene, such multiple O-antigens O: 1, 4, 5, 12 engineered to be present on the chromosome. To achieve multiple alternating sets of antigens, coexistence of a set of alternative, non-overlapping antigens such as O: 6, 7 under control of a separate inducible promoter are constructed. Thus, a bacterial culture may be induced to have one set of antigens for a first injection, and may be induced to have a second set of antigens for a second injection, and so on. Similarly, following a first injection with induced expression of one set of antigens, the first inducer may be curtailed, and the inducer for the second set of antigens initiated, thus avoiding prolonged exposure to the immune systems and avoiding immune elimination.
A novel acetylsalicylic acid (aspirin)-inducible promoter is also encompassed based upon the Salmonella multiple antibiotic resistance operon (mar) promoter/operator regulon (Sulavik et al., 1997, The Salmonella typhimurium mar locus: molecular and genetic analyses and assessment of its role in virulence. J. Bacteriol. 179: 1857-1866; Barbosa and Levy, 2000 Differential expression of over 60 chromosomal genes in Escherichia coli by constitutive expression or MarA, J. Bacteriol 182: 3467-3474; Alekshun and Levy, 2004, The Escherichia coli mar locus-antibiotic resistance and more, ASM News 70: 451-456), Genbank accession number U54468.1 (which, by itself, does not confer antibiotic resistance), each of which is expressly incorporated herein by reference in its entirety. The regulon consists of the mar promoter/operator region, the MarR negative regulator, the MarA positive regulator, and the downstream start codon (ATG) that is used for expression of the gene(s) of interest such as the rfb cluster. Alternatively, use of the mar regulon also encompasses inducible expression of other anti-cancer proteins, protease inhibitors and targeted toxins and antitumor enzymes and/or genetically engineered phage and phagemids (Bermudes U.S. Pat. No. 8,524,220, Protease Inhibitor: Protease sensitivity expression system composition and methods improving the therapeutic activity and specificity of proteins delivered by bacteria; U.S. Pat. No. 8,241,623, Protease Sensitivity Expression System; U.S. Pat. No. 8,623,350 Protease inhibitor: protease sensitivity expression system and method improving the therapeutic activity and specificity of proteins and phage and phagemids delivered by bacteria) or combinations with antivascular agents, such as platelet factor 4 and thrombospondin, alone or in combination (Bermudes et al., U.S. Pat. No. 6,962,696, U.S. Pat. No. 7,452,531 Compositions and Methods for Tumor-Targeted Delivery of Effector Molecules) and other anticancer agents (e.g., WO2009/126189, WO03/014380, WO/2005/018332, WO/2008/073148, US 2003/0059400 U.S. Pat. Nos. 7,452,531, 7,354,592, 6,962,696, 6,923,972, 6,863,894, 6,685,935, 6,475,482, 6,447,784, 6,190,657 and 6,080,849, each of which is expressly incorporated herein by reference in its entirety). The DNA containing the upstream regulon promoter/operator, the MarR and MarA genes and ending with the start codon (ATG; caps) to which may be fused as the initiating codon a gene or genes of interest is encompassed by:







SEQ ID NO: 003


cagtgtgcaagttaatatcctctacaacctataacctgtaattatcaatt


 


agttacaagttatcacagcacaataccccggacgccttttagcaaatcgt


 


ggcatcggccaattcatttagttgacttatacttgcctgggcaatagtat


 


ctgacgaaattaattacttgccggggcaaccattttgaaaagcaccagtg


 


atctgttcaATGaaatcattccgctgggtcgcttgatctacatggtaaat


 


cagaaaaaagatcgcctgttaaataactatttatccccgctggatatcac


 


cgcaacacagtttaaagtgctttgctcgatacgctgcgcgggatgtatta


 


ccccggttgaacttaaaaaagtgctgtctgtcgatctcggcgcattgacg


 


cggatgctcgaccgcctgctgtgcaaaggctggatcgaaagactgccgaa


 


tcctaatgacaaacgcggcgtactggtgaagctaacgccggacggcgcgg


 


caatttgtgagcaatgtcatcaacgaccagggcaagacctgcatcaggaa


 


ttaacaaaaaacttaacggcggacgaagtggcaacgcttgagtatttgct


 


caagaaaattctgccgtagacaaaaaagaggtATGacgatgtccagacgc


 


aacactgacgctattactattcatagcattttggactggatcgaggataa


 


cctggagtcgccgctctcactggaaaaagtgtctgagcgttcaggatatt


 


ccaaatggcacctgcaacggatgtttaaaaaagagaccggtcattcatta


 


ggccaatacatccgcagccgtaaaatgacggaaatcgcgcaaaaattaaa


 


agagagcaacgagcccattctctatctggcggaacgctatggctttgagt


 


cacagcaaacattgacccggacgttcaaaaactattttgatgtgccgcca


 


cacaaataccggatcaccaatatgcatggcgaatcacggtatatgctgcc


 


gctgaaccatggcaactactagtttgtttatgcgccacgcgaagagcacc


 


ATG






In another embodiment, the Seq. ID NO.:003 bp 1-209, with the ATG of MarR at 210-212 is used as the start codon. In a more preferred embodiment, the Seq. ID NO.:003 bp 1-632, with the ATG of MarA at 633-635 is used as the start codon. Optionally, in any of the promoters described above, a bacterial termination sequence can be placed upstream of bp 1 (Peters et al., 2011 Bacterial transcriptional terminators: the RNA3′end chronicals, J. Mol. Biol. 412: 793-813), expressly incorporated herein by reference in its entirety.
5.4. Bacteria that deliver ligands against immunosuppressive factors including Programmed Cell Death Protein 1 Ligand (PD-L1), PD-L1 Receptor (PD-1) or CTLA-4.
Bacteria that reside within tumors rely upon nutrients obtained from the host. While necrotic tissue formed due to tissue hypoxia is believed to be one of the primary sources of nutrients for bacteria colonizing tumors, cell death due to immune functions such as those of cytotoxic T-cells attaching tumor cells also have the potential to contribute to the growth and expansion of intratumoral bacteria by providing nutrients. An object of one embodiment of the technology is to use the bacteria described herein alone or in combination with other aspects of the technology that increase the bacteria's ability to colonize and expand within tumors. Ligands against immuno-suppressive factors such PD-L1 and CTLA-4 include antibodies, affibodies (protein A affinity-based ligands), armadillo repeat protein-based scaffolds, adnectins, anticalins, lipocalins, Kunitz domain-based binders, avimers, knottins, fynomers, atrimers and DARPins (designed ankyrin repeat proteins) and cytotoxic T-lymphocyte associated protein-4 (CTLA4)-based binders (Weidle et al., 2013 The emerging role of new protein scaffold-based agents for treatment of cancer. Cancer Genomics Protomics 10: 155-168, expressly incorporated herein by reference in its entirety). Ligands such as those against PD-L1 such as those described by Gao et al., 2014 (Small peptides elicit anti-tumor effects in CT26 model through blocking PD-L1/PD-1 (TUM2P.900, Journal of Immunology 192 (1 Supplement) 71.24) are expressed using secretion proteins described above, such as fusions with YebF. Anti-CLA-4 anticalin PRS-010 is also engineered as a YebF fusion, and may optionally contain a protease cleavage site for release of the anticalin within the tumor. CLA-4 anticalins may also be expressed by filamentous phage or as bacterial surfface displayed (WO2012072806A1; Muteins of human liopcalin 2 with affinity for CTLA-4; 20090042785 Compound with affinity for the cytotoxic T lymphocyte-associated antigen (CTLA-4; 20100285564 Anticalins; 20100160612 Muteins Of Tear Lipocalin With Affinity For The T-Cell Coreceptor CD4, each of which is expressly incorporated herein by reference in its entirety). Affibodies are generated as described by Felwisch and Tomachev 2012, Enginnering of affibody molecules for therapy and diagnosis. Methods Molecular Biol 899: 103-126). DARPins are designed and screened for as previously described (Stumpp and Amstutz 2007, DARPins: a true alternative to antibodies, Curr Opin Drug Discov. Devel. 10: 159-153; Zahnd et al., 2010, Efficient tumor targeting with high-affinity designed ankyrin repeat proteins: Effects of Affinity and Molecular Size, Cancer Res 2010; 70:1595-1605; WO/2013022091 Therapeutic Agent For Autoimmune Diseases Comprising PD-1 Agonist), each of which is expressly incorporated herein by reference in its entirety. The localized production of the PD-L1 or CTLA-4 agonists is distinctly different than systemic administration of agonists such as antibodies, because systemic administration of PD-L1 or CTLA-4 agonists has the potential to have systemic immune collateral damages, whereas the intratumoral production limits the T-cell response to the tumor environment. Combination with smaller size bacteria, alternating surface antigens and tryptophanase (see below) further enhance the overall antitumor effect.
5.5. Bacteria that Express the Tryptophanase.
Bacterial production of metabolites that are toxic to tumor cells such as indol, a product of tryptophanase, is used to enhance bacterial spread within the tumor by killing tumor cells by the production of the indol metabolite that the bacteria are not themselves affected by. The tumor cells are further starved for tryptophane by the depletion of tryptophan by tryptophanse. The combination of these effects is further enhanced by the other pharmacokinetic enhancements, tumor penetration, persistence and intra-tumoral spreading. Expression of tryptophanase may use the Escherichia coli genes or any homologous genes; those of the enterobacteriaceae are a preferred embodiment. In E. coli which are encoded by a transcribed leader region, tnaL (also known as tnaC), and two larger structural genes, where tnaA, which encodes the degradative enzyme and tnaB which together with the tnaL product are involved in tryptophane transport. In E. coli the genes exist as an operon and are expressed using a single promoter, such as the constitutive promoter or an inducible promoter. Alternatively, the endogenous tryptophanase or a modified tryptophanase promoter (Sitney et al., 1996, Use of a Modified Tryptophanase Promoter to Direct High-Level Expression of Foreign Proteins in E. coli, Ann. N.Y. Acad. Sci. 782: 297-310, expressly incorporated herein by reference in its entirety) may be used. The genes encode the 3 peptides:
TnaL (TnaC):










MNILHICVTSKWFNIDNKIVDHRP,
SEQ ID NO: 004













SEQ ID NO: 005


TnaA: MENFKHLPEPFRIRVIEPVKRTTRAYREEAIIKSGMNPFLLDSE


 


DVFIDLLTDSGTGAVTQSMQAAMMRGDEAYSGSRSYYALAESVKNIFGYQ


 


YTIPTHQGRGAEQIYIPVLIKKREQEKGLDRSKMVAFSNYFFDTTQGHSQ


 


INGCTVRNVYIKEAFDTGVRYDFKGNFDLEGLERGIEEVGPNNVPYIVAT


 


ITSNSAGGQPVSLANLKAMYSIAKKYDIPVVMDSARFAENAYFIKQREAE


 


YKDWTIEQITRETYKYADMLAMSAKKDAMVPMGGLLCMKDDSFFDVYTEC


 


RTLCVVQEGFPTYGGLEGGAMERLAVGLYDGMNLDWLAYRIAQVQYLVDG


 


LEEIGVVCQQAGGHAAFVDAGKLLPHIPADQFPAQALACELYKVAGIRAV


 


EIGSFLLGRDPKTGKQLPCPAELLRLTIPRATYTQTHMDFIIEAFKHVKE


 


NAANIKGLTFTYEPKVLRHFTAKLKEV













SEQ ID NO: 006


TnaB: MTDQAEKKHSAFWGVMVIAGTVIGGGMFALPVDLAGAWFFWGAF


 


ILIIAWFSMLHSGLLLLEANLNYPVGSSFNTITKDLIGNTWNIISGITVA


 


FVLYILTYAYISANGAIISETISMNLGYHANPRIVGICTAIFVASVLWLS


 


SLAASRITSLFLGLKIISFVIVFGSFFFQVDYSILRDATSSTAGTSYFPY


 


IFMALPVCLASFGFHGNIPSLIICYGKRKDKLIKSVVFGSLLALVIYLFW


 


LYCTMGNIPRESFKAIISSGGNVDSLVKSFLGTKQHGIIEFCLLVFSNLA


 


VASSFFGVTLGLFDYLADLFKIDNSHGGRFKTVLLTFLPPALLYLIFPNG


 


FIYGIGGAGLCATIWAVIIPAVLAIKARKKFPNQMFTVWGGNLIPAIVIL


 


FGITVILCWFGNVFNVLPKFG






The complete sequence of the coding region from the start of the first peptide to the stop of the 3rd peptide is:







SEQ ID NO: 007


ATGaatatcttacatatatgtgtgacctcaaaatggttcaatattgacaa


 


caaaattgtcgatcaccgcccttgatttgcccttctgtagccatcaccag


 


agccaaaccgattagattcaatgtgatctatttgtttgctatatcttaat


 


tttgccttttgcaaaggtcatctctcgtttatttacttgttttagtaaat


 


gatggtgcttgcatatatatctggcgaattaatcggtatagcagatgtaa


 


tattcacagggatcactgtaattaaaataaatgaaggattatgtaatgga


 


aaactttaaacatctccctgaaccgttccgcattcgtgttattgagccag


 


taaaacgtaccactcgcgcttatcgtgaagaggcaattattaaatccggt


 


atgaacccgttcctgctggatagcgaagatgtttttatcgatttactgac


 


cgacagcggcaccggggcggtgacgcagagcatgcaggctgcgatgatgc


 


gcggcgacgaagcctacagcggcagtcgtagctactatgcgttagccgag


 


tcagtgaaaaatatctttggttatcaatacaccattccgactcaccaggg


 


ccgtggcgcagagcaaatctatattccggtactgattaaaaaacgcgagc


 


aggaaaaaggcctggatcgcagcaaaatggtggcgttctctaactatttc


 


tttgataccacgcagggccatagccagatcaacggctgtaccgtgcgtaa


 


cgtctatatcaaagaagccttcgatacgggcgtgcgttacgactttaaag


 


gcaactttgaccttgagggattagaacgcggtattgaagaagttggtccg


 


aataacgtgccgtatatcgttgcaaccatcaccagtaactctgcaggtgg


 


tcagccggtttcactggcaaacttaaaagcgatgtacagcatcgcgaaga


 


aatacgatattccggtggtaatggactccgcgcgctttgctgaaaacgcc


 


tatttcatcaagcagcgtgaagcagaatacaaagactggaccatcgagca


 


gatcacccgcgaaacctacaaatatgccgatatgctggcgatgtccgcca


 


agaaagatgcgatggtgccgatgggcggcctgctgtgcatgaaagacgac


 


agcttctttgatgtgtacaccgagtgcagaaccctttgcgtggtgcagga


 


aggcttcccgacatatggcggcctggaaggcggcgcgatggagcgtctgg


 


cggtaggtctgtatgacggcatgaatctcgactggctggcttatcgtatc


 


gcgcaggtacagtatctggtcgatggtctggaagagattggcgttgtctg


 


ccagcaggcgggcggtcacgcggcattcgttgatgccggtaaactgttgc


 


cgcatatcccggcagaccagttcccggcacaggcgctggcctgcgagctg


 


tataaagtcgccggtatccgtgcggtagaaattggctctttcctgttagg


 


ccgcgatccgaaaaccggtaaacaactgccatgcccggctgaactgctgc


 


gtttaaccattccgcgcgcaacatatactcaaacacatatggacttcatt


 


attgaagcctttaaacatgtgaaagagaacgcggcgaatattaaaggatt


 


aacctttacgtacgaaccgaaagtattgcgtcacttcaccgcaaaactta


 


aagaagtttaattaatactacagagtggctataaggatgttagccactct


 


cttaccctacatcctcaataacaaaaatagccttcctctaaaggtggcat


 


catgactgatcaagctgaaaaaaagcactctgcattttggggtgttatgg


 


ttatagcaggtacagtaattggtggaggtatgtttgctttacctgttgat


 


cttgccggtgcctggtttttctggggtgcctttatccttatcattgcctg


 


gttttcaatgcttcattccgggttattgttattagaagcaaatttaaatt


 


atcccgtcggctccagttttaacaccatcaccaaagatttaatcggtaac


 


acctggaacattatcagcggtattaccgttgccttcgttctctatatcct


 


cacttatgcctatatctctgctaatggtgcgatcattagtgaaacgatat


 


caatgaatttgggttatcacgctaatccacgtattgtcgggatctgcaca


 


gccattttcgttgccagcgtattgtggttaagttcgttagccgccagtcg


 


tattacctcattgttcctcgggctgaagattatctcctttgtgatcgtgt


 


ttggttcttttttcttccaggtcgattactccattctgcgcgacgccacc


 


agctccactgcgggaacgtcttacttcccgtatatctttatggctttgcc


 


ggtgtgtctggcgtcatttggtttccacggcaatattcccagcctgatta


 


tttgctatggaaaacgcaaagataagttaatcaaaagcgtggtatttggt


 


tcgctgctggcgctggtgatttatctcttctggctctattgcaccatggg


 


gaatattccgcgagaaagctttaaggcgattatctcctcaggcggcaacg


 


ttgattcgctggtgaaatcgttcctcggcaccaaacagcacggcattatc


 


gagttttgcctgctggtgttctctaacttagctgttgccagttcgttctt


 


tggtgtcacgctggggttgttcgattatctggcggacctgtttaagattg


 


ataactcccacggcgggcgtttcaaaaccgtgctgttaaccttcctgcca


 


cctgcgttgttgtatctgatcttcccgaacggctttatttacgggatcgg


 


cggtgccgggctgtgcgccaccatctgggcggtcattattcccgcagtgc


 


ttgcaatcaaagctcgcaagaagtttcccaatcagatgttcacggtctgg


 


ggcggcaatcttattccggcgattgtcattctctttggtataaccgtgat


 


tttgtgctggttcggcaacgtctttaacgtgttacctaaatttggcTAA






It is understood that other enzymes, such as tyrosinase, may be genetically engineered within the Salmonella, instead of or together with the tryptophanase, in accordance with known principles and the discussion herein.
5.6. Bacteria with Enhanced Resistance to Serum.
Bacterial with enhanced resistance to serum and serum components are derived by several additional means, and can be used alone or in combination with sialic acid modifications and/or CO2 resistance.
5.6.1. Selection for increased serum half-life. Mutants can be selected from spontaneous populations, or mutagenized populations as described above. Bacteria with improved serum half-life can be selected by taking blood samples and selecting the bacteria that are found at the tail end of the serum circulation, re-injecting the same bacteria after regrowth, and again selecting for bacteria at the end of the circulation in serum as previously applied to bacteriophage (Merril et al., 1996, Long-circulating bacteriophage as antibacterial agents, PNAS 93: 3188-3192), expressly incorporated herein by reference in its entirety. The selection may be performed in live animals, including mice, rats, guinea pigs, rabbits, pigs, dogs, cats, monkeys and human volunteers. The procedure may also be carried out in vitro, using blood from any of the above donors by successive passages and isolation of individual colonies resistant to complement and/or other serum components.
5.6.2. Expression of serum-resistance genes. Expression or over-expression of serum resistance genes can be accomplished by conventional heterologous expression methods known to those skilled in the arts. The serum resistome of E. coli has been described (Phan et al., 2013 The serum resistome of a globally disseminated multidrug resistant uropathogenic Escherichia coli clone, PLoS Genetics DOT: 10.1371/journal.pgen.1003834, incorporated by reference in its entirety). Serum resistance genes also include the Salmonella Rck (resistance to complement killing) and PagC proteins or its homologues from E. coli (Lom) Yersinia entercolitica (ail) and Enterobacter cloacae (OmpX) (Heffernan E J, et al., 1992. The Salmonella typhimurium virulence plasmid complement resistance gene rck is homologous to a family of virulence-related outer membrane protein genes, including pagC and ail. J. Bacteriol. 174: 84-91; Ho et al., 2011, Functional Recruitment of Human Complement Inhibitor C4b-Binding Protein to Outer Membrane Protein Rck of Salmonella PLoS ONE 6(11): e27546. doi:10.1371/journal.pone.0027546), Cirillo D M, et al., 1996. Identification of a domain in Rck, a product of the Salmonella typhimurium virulence plasmid, required for both serum resistance and cell invasion. Infect. Immun. 64: 2019-2023), each of which is expressly incorporated herein by reference in its entirety. Antibodies to Rck may also be used to select strains with increased expression. Resistance can also be obtained by expression of other genes, such as the melittin resitance gene pqaB (Baker et al., 1999, The Salmonella typhi melittin resistance gene pqaB affects intracellular growth in PMA-differentiated U937 cells, Polymyxin B resistance and lipopolysaccharide, Microbiology 145: 367-378), expressly incorporated herein by reference in its entirety. Furthermore, when the melittin resistance gene is expressed, the lytic protein melittin or melittin conjugates to targeted peptides may be used as antitumor agents (Liu et al., 2013, A novel melittin-MhIL-2 fusion protein inhibits the growth of human ovarian cancer SKOV3 cells in vitro and in vivo tumor growth, Cancer Immunol. Immunotherapy 62: 889-895), expressly incorporated herein by reference in its entirety. Other targeting peptides fused to melittin may be any of those from the references herein.
FIGURE LEGEND
The figures show compositions and methods to modify bacteria of the present technology.
FIGS. 1A-1C. Bacteria with Reduced Size.
FIG. 1A. The mechanism for selecting bacteria with reduced size by passage of a population of bacteria containing spontaneous mutants, induced mutants and/or suppressor mutants through progressively smaller syringe cartridge microporous filters of 0.65, 0.45 and 0.22 μm. FIG. 1B. Facilitation of reduced size bacteria by genome reduction. Following genome reduction methods, the bacteria may be selected for reduced size as shown in FIG. 1A. FIG. 1C. Facilitation of reduced size bacteria by genome compaction through addition of histone-like proteins from Chalamydia and the appropriate target sequence. Following genome reduction methods, the bacteria may be selected for reduced size as shown in FIG. 1A. The process may be further combined with the method of FIG. 1B.
FIGS. 2A-2C. Bacteria with a Protective Sialic Acid Coat.
FIG. 2A. The genes necessary for LPS sialyation are cloned into and expressed by the bacteria, resulting in the LPS O-antigen being sialyated (Severi et al., 2007, Sialic acid utilization by bacterial pathogens, Microbiology 153: 2817-2822, expressly incorporated herein by reference in its entirety). FIG. 2B. The genes necessary for PSA capsule biosynthesis and export are cloned into and expressed by the bacteria, resulting in a sialic acid capsule. FIG. 2C. The genes for sialic acid scavenging and utilization are cloned into and expressed by the bacteria, resulting in the LPS O-antigen being sialyated.
FIGS. 3A-3C Bacteria with Inducible Expression of Alternate Surface Antigens.
FIG. 3A. The wild type rfb gene cluster and rfc gene encoding the O: 1, 4, 5, 12 antigen, and the wild type H1 flagellar antigen, all with wild type promoters. FIG. 3B. Three different rfb gene cluster with the rfc gene encoding the O: 1, 4, 5, 12 antigens, and the H1 flagellar antigen under control of the sulA (x-ray inducible) promoter; the O: 6, 7 antigens, and the H2 flagellar antigen under control of the tet (tetracycline) inducible promoter, and; the O: 3, 15, 34 antigens and the H3 flagellar antigen under control of the ara (arabinose) inducible promoter. Successive treatment with X-rays, tetracycline and arabinose respectively results in alternate expression of non-overlapping surface antigens. FIG. 3C. the mar regulon which consists of the mar promoter/operator, the MarR negative regulatory gene, the MarA positive regulatory gene, and a downstream start codon (ATG) which would normally comprise the start of the MarB coding sequence, which is used for the rfb O-antigen gene cluster. Alternatively the MarA regulon may be used for inducible expression of other anti-cancer effector genes.
FIG. 4. Bacteria Delivering Ligands Against PD-1 Ligand (PD-L1).
Bacteria expressing a PD-L1 agonist (a YebF fusion of an anti-PD-L1 DARPin) results in blocking the PD-L1 signal, thereby activating T-cells that destroy tumor cells and increase the number of bacteria within the tumor.
FIG. 5 Shows Bacteria that Express the E. coli Tryptophanase.
The operon for tryptophanase including trypLAB are cloned and expressed in the bacteria, resulting in tumor cell toxicity, antitumor activity and increased tumor penetration of the bacteria.
EXAMPLES
In order to more fully illustrate the invention, the following examples are provided.
Example 1
Isolation of Bacteria with Reduced Size Based on Spontaneous Mutagenesis
By way of example, the attenuated antineoplastic bacteria, or precursors to antineoplastic bacteria, are selected from a pool of mutants. The mutants may either be those that are spontaneous within a normal genetic background (i.e., a normal population), spontaneous mutants in a non-suppressed environmentally sensitive genetic background (e.g., msbB−), or spontaneous mutants within a mutator background. Bacteria of a normal genetic background and mutator backgrounds (e.g., mutL, mutS, mutH, alone or in combination) are grown from low density, e.g., a single colony inoculated into 100 ml of standard media such as Luria broth. Bacteria of an environmentally sensitive genetic background, such as strain YS1 (Murray et al., 2001, Extragenic suppressors of msbB− growth defects in Salmonella. J. Bacteriol. 183: 5554-5561, expressly incorporated herein by reference in its entirety) are grown from low density, e.g., a single colony inoculated into 100 ml of media wherein the media contains a substance to which the bacteria are sensitive, such as 6 mM EGTA.
Bacteria with reduced size are selected for by passage through successively smaller pore sizes. Selection begins with passage through a 0.65 μM filter. Bacteria obtained this way are rechecked by repassage through the filter, with a high percentage of passage indicating bacteria with smaller size. These bacteria are then again subjected to the initial growth conditions above and then again selected for passage through a filter except that a 0.45 μM pore size is used. The process is then repeated for a 0.22 μM pore size. The mutations resulting in the bacteria passing through smaller pore sizes are determined by standard genetic means (Murray et al., 2001) or by genome sequencing.
Example 2
Isolation of Bacteria with Reduced Size Based on Random Mutagenesis
The selection process described above is applied to bacteria that have been randomly mutagenized. Random mutagenesis can consist of either chemically/physically induced mutations such as those caused by nitrosoguanidine and ultraviolet light (Pawelek et al., 1997). The selection process described above is applied to bacteria that have been randomly mutagenized.
Example 3
Generation of Bacteria with a Protective Sialic Acid Coat
De novo synthesis of lipopolysaccharide with sialic acid is accomplished by heterologous expression of NeuA, NeuB, NeuC, SiaB, Lic3A, Lic3B, and SOAT (sialic acid O-acyltransferase) (Severi et al., 2007, Sialic acid utilization by bacterial pathogens, Microbiology 153: 2817-2822, expressly incorporated herein by reference in its entirety) as shown in FIGS. 2A-2C. Heterologous expression is achieved using synthetic biology and methods known to those skilled in the arts, including the methods described by King et al., 2009 (Tumor-targeted Salmonella typhimurium overexpressing cytosine deaminase: a novel, tumor-selective therapy, Meth. Mol. Biol. 542: 649-659), expressly incorporated herein by reference in its entirety. Induction of the sialic acid coat may be performed in vitro during manufacturing, or in vivo, following systemic administration.
Example 4
Generation of Bacteria with Inducible Expression of Alternate Surface Antigens
Methods for deriving heterologous O-antigens include methods known to those skilled in the arts, including those described by Favre et al., WO/1997/014782, and Roland WO/2000/004919, each of which is expressly incorporated herein by reference in its entirety. 0-antigen synthesis is directed by the rfb gene cluster which encodes enzymes involved in biosynthesis of the monomer sugar unit, and the rfc gene, which encodes the O-antigen polymerase responsible for the polymerization of the sugar unit into a high molecular weight polysaccharide chain (Sugiyama et al., 1991 Expression of the Cloned Escherichia coli 09 rfb Gene in Various Mutant Strains of Salmonella typhimurium, J. Bacteriol. 173:55-58; Collins et al. 1991, Molecular Cloning, Characterization, and Nucleotide Sequence of the rfc Gene, Which Encodes an O-Antigen Polymerase of Salmonella typhimurium, J. Bacteriol. 173:2521-2529), each of which is expressly incorporated herein by reference in its entirety. The antigens are chosen such that alternate expression does not have overlap. For example the O-antigens of the S. typhimurium serovar are O: 1, 4, 5, 12, whereas those of S. Montevideo, O: 6, 7, and those of E3 group are O: 3,15,34. The rfb gene cluster and rfc gene may be part of a single synthetic operon (polycistronic), or may be separate, monocystronic constructs, with separate individual promoters of the same type used to drive the expression of their respective genes. Use of separate inducible promoter for more than one antigen allows for their expression to occur simultaneously, sequentially, or alternating (repeated) depending upon which inducers are administer (FIGS. 3A-3C). Thus, to achieve multiple alternating sets of antigens, coexistance of a set of alternative, non-overlapping under control of a separate inducible promoter are constructed. Thus, a bacterial culture may be induced to have one set of antigens for a first injection, and may be induced to have a second set of antigens for a second injection, and so on. Similarly, following a first injection with induced expression of one set of antigens, the first inducer may be curtailed, and the inducer for the second set of antigens initiated, thus avoiding prolonged exposure to the immune systems and avoiding immune elimination.
Example 4
Generation of Bacteria Delivering Ligands Against PD-1 Ligand (PDL-1)
Ligands against PDL1 include antibodies, affibodies (protein A affinity-based ligands), adnectins, anticalins and DARPins (designed ankyrin repeat proteins). Ligands against PDL1 such as affibodies and DARPins are expressed using secretion proteins described above, such as fusions with YebF (FIG. 4). Affibodies are generated as described by Felwisch and Tomachev 2012, Enginnering of affibody molecules for therapy and diagnosis. Methods Molecular Biol 899: 103-126). DARPins are designed and screened for as previously described (Stumpp and Amstutz 2007, DARPins: a true alternative to antibodies, Curr Opin Drug Discov. Devel. 10: 159-153; Zahnd et al., 2010, Efficient tumor targeting with high-affinity designed ankyrin repeat proteins: Effects of Affinity and Molecular Size, Cancer Res 2010; 70:1595-1605; WO/2013022091 Therapeutic Agent For Autoimmune Diseases Comprising PD-1 Agonist), each of which is expressly incorporated herein by reference in its entirety. Combination with smaller size bacteria, alternating surface antigens and tryptophanase (see below) further enhance the overall antitumor effect.
Example 5
Generation of Bacteria that Express the E. coli Tryptophanase
Expression of tryptophanase and demonstration of enhanced antitumor activity may be conducted as follows. Cloning of the tryptophanase operon uses methods known to those skilled in the arts, including PCR-based cloning (Forward primer=Tryp Kpn Nsi F1 TCggtacccAGGAGGAAttcaCCATGCATaatatcttacatatatgtgtgAcctcaaaat SEQ ID NO: 008 and reverse primer=Tryp Xba R1 gatcTCTAGAgaaggatTTAgccaaatttaggtaacac SEQ ID NO: 009). Cloning into an expression vector such as a modified pTrc99a with the arabinose promoter







SEQ ID NO: 010


GGGGGCGGCCGCAAGAAACCAATTGTCCATATTGCATCAGACATTGCCGT


 


CACTGCGTCTTTTACTGGCTCTTCTCGCTAACCAAACCGGTAACCCCGCT


 


TATTAAAAGCATTCTGTAACAAAGCGGGACCAAAGCCATGACAAAAACGC


 


GTAACAAAAGTGTCTATAATCACGGCAGAAAAGTCCACATTGATTATTTG


 


CACGGCGTCACACTTTGCTATGCCATAGCATTTTTATCCATAAGATTAGC


 


GGATCCTACCTGACGCTTTTTATCGCAACTCTCTACTGTTTCTCCATACC


 


CGTTTTTTTGGGCTAGCGAATTCGAGCTCGGTACCCAGGAGGAATTCACC


 


ATGGAATTCGAGCTCGGTACCCGGGGATCCTCTAGAGTCGACCTGCAGGC


 


ATGCAAGCTTGGCTGTTTTGGCGGATGAGAGAAGATTTTCAGCCTGATAC


 


AGATTAAATCAGAACGCAGAAGCGGTCTGATAAAACAGAATTTGCCTGGC


 


GGCAGTAGCGCGGTGGTCCCACCTGACCCCATGCCGAACTCAGAAGTGAA


 


ACGCCGTAGCGCCGATGGTAGTGTGGGGTCTCCCCATGCGAGAGTAGGGA


 


ACTGCCAGGCATCAAATAAAACGAAAGGCTCAGTCGAAAGACTGGGCCTT


 


TCGTTTTATCTGTTGTTTGTCGGTGAACGCTCTCCTGAGTAGGACAAATC


 


CGCCGGGAGCGGATTTGAACGTTGCGAAGCAACGGCCCGGAGGGTGGCGG


 


GCAGGACGCCCGCCATAAACTGCCAGGCATCAAATTAAGCAGAAGGCCAT


 


CCTGACGGATGGCCTTTTTGCGTTTCTACAAACTCTTTTTGTTTATTTTT


 


CTAAATACATTCAAATATGTATCCGCTCATGAGACAATAACCCTGATAAA


 


TGCTTCAATAATATTGAAAAAGGAAGAGTATGAGTATTCAACATTTCCGT


 


GTCGCCCTTATTCCCTTTTTTGCGGCATTTTGCCTTCCTGTTTTTGCTCA


 


CCCAGAAACGCTGGTGAAAGTAAAAGATGCTGAAGATCAGTTGGGTGCAC


 


GAGTGGGTTACATCGAACTGGATCTCAACAGCGGTAAGATCCTTGAGAGT


 


TTTCGCCCCGAAGAACGTTTTCCAATGATGAGCACTTTTAAAGTTCTGCT


 


ATGTGGCGCGGTATTATCCCGTGTTGACGCCGGGCAAGAGCAACTCGGTC


 


GCCGCATACACTATTCTCAGAATGACTTGGTTGAGTACTCACCAGTCACA


 


GAAAAGCATCTTACGGATGGCATGACAGTAAGAGAATTATGCAGTGCTGC


 


CATAACCATGAGTGATAACACTGCGGCCAACTTACTTCTGACAACGATCG


 


GAGGACCGAAGGAGCTAACCGCTTTTTTGCACAACATGGGGGATCATGTA


 


ACTCGCCTTGATCGTTGGGAACCGGAGCTGAATGAAGCCATACCAAACGA


 


CGAGCGTGACACCACGATGCCTACAGCAATGGCAACAACGTTGCGCAAAC


 


TATTAACTGGCGAACTACTTACTCTAGCTTCCCGGCAACAATTAATAGAC


 


TGGATGGAGGCGGATAAAGTTGCAGGACCACTTCTGCGCTCGGCCCTTCC


 


GGCTGGCTGGTTTATTGCTGATAAATCTGGAGCCGGTGAGCGTGGGTCTC


 


GCGGTATCATTGCAGCACTGGGGCCAGATGGTAAGCCCTCCCGTATCGTA


 


GTTATCTACACGACGGGGAGTCAGGCAACTATGGATGAACGAAATAGACA


 


GATCGCTGAGATAGGTGCCTCACTGATTAAGCATTGGTAACTGTCAGACC


 


AAGTTTACTCATATATACTTTAGATTGATTTAAAACTTCATTTTTAATTT


 


AAAAGGATCTAGGTGAAGATCCTTTTTGATAATCTCATGACCAAAATCCC


 


TTAACGTGAGTTTTCGTTCCACTGAGCGTCAGACCCCGTAGAAAAGATCA


 


AAGGATCTTCTTGAGATCCTTTTTTTCTGCGCGTAATCTGCTGCTTGCAA


 


ACAAAAAAACCACCGCTACCAGCGGTGGTTTGTTTGCCGGATCAAGAGCT


 


ACCAACTCTTTTTCCGAAGGTAACTGGCTTCAGCAGAGCGCAGATACCAA


 


ATACTGTCCTTCTAGTGTAGCCGTAGTTAGGCCACCACTTCAAGAACTCT


 


GTAGCACCGCCTACATACCTCGCTCTGCTAATCCTGTTACCAGTGGCTGC


 


TGCCAGTGGCGATAAGTCGTGTCTTACCGGGTTGGACTCAAGACGATAGT


 


TACCGGATAAGGCGCAGCGGTCGGGCTGAACGGGGGGTTCGTGCACACAG


 


CCCAGCTTGGAGCGAACGACCTACACCGAACTGAGATACCTACAGCGTGA


 


GCTATGAGAAAGCGCCACGCTTCCCGAAGGGAGAAAGGCGGACAGGTATC


 


CGGTAAGCGGCAGGGTCGGAACAGGAGAGCGCACGAGGGAGCTTCCAGGG


 


GGAAACGCCTGGTATCTTTATAGTCCTGTCGGGTTTCGCCACCTCTGACT


 


TGAGCGTCGATTTTTGTGATGCTCGTCAGGGGGGCGGAGCCTATGGAAAA


 


ACGCCAGCAACGCGGCCTTTTTACGGTTCCTGGCCTTTTGCTGGCCTTTT


 


GCTCACATGTTCTTTCCTGCGTTATCCCCTGATTCTGTGGATAACCGTAT


 


TACCGCCTTTGAGTGAGCTGATACCGCTCGCCGCAGCCGAACGACCGAGC


 


GCAGCGAGTCAGTGAGCGAGGAAGCGGAAGAGCGCCTGATGCGGTATTTT


 


CTCCTTACGCATCTGTGCGGTATTTCACACCGCATATG






using KpnI and XbaI restriction endonucleases operably links the inducible ara promoter to a start codon (ATG) and results in a polycistronic message that produces all three peptides.
Successful expression of tryptophanase is determined by the addition of Kovac's reagent, which consists of isoamyl alcohol and par-dimethylaminobenzaldhyde in concentrated hydrochloric acid; a positive reaction is indicated by a red color. Determination of antitumor activity is performed according to the methods of Pawelek et al. (1997, Tumor-targeted Salmonella as a novel anticancer vector, Cancer Research 57: 4537-4544), expressly incorporated herein by reference in its entirety, with one control being mice bearing melanoma tumors without any treatment, a second control being the parental salmonella VNP20009 without the tryptophanase, and a test group consisting of the VNP20009 expressing the tryptophanase. The expression plasmid is transformed to a suitable Salmonella strain, such as VNP20009 (Low, et al., 2004, Construction of VNP20009, a novel, genetically stable antibiotic sensitive strain of tumor-targeting Salmonella for parenteral administration in humans, Methods Mol Med 90: 47-60) and used to treat mice for preclinical studies (Pawelek et al., 1997, Tumor-targeted Salmonella as a novel anticancer agent, Cancer Research 57: 4537-4544; Low et al., 1999, Lipid A mutant salmonella with suppressed virulence and TNF-alpha induction retain tumor-targeting in vivo, Nature Biotechnol. 17: 37-41; Lossner et al., 2007, Cell Microbiol. 9: 1529-1537; WO/2006/048344; Swofford et al., 2014 Biotechnology and Bioengineering 111: 1233-1245), and humans for clinical studies (Toso et al., 2002, Phase I study of the intravenous administration of attenuated Salmonella typhimurium to patients with metastatic melanoma, J. Clin. Oncol 20: 142-152), each of which is expressly incorporated herein by reference in its entirety.
Example 6
Selection of Bacteria with Increased Serum Survival and Increased Circulation Time
Bacteria with increased serum circulation time are selected from natural populations, mutagenized populations, suppressed strains, partially suppressed strains, as described above. By way of specific example, strains with improved serum half-life may be selected for starting with the clinical strain VNP20009.
VNP20009 are injected into a 20 g mouse at 1×106 CFU/mouse. Bacteria are periodically sampled from blood, at 15 min, 30 min, 60 min, 120 min, 240 min, 480 min, 960 min, 1920 min and plated by serial dilutions of 100-10−6 and incubated overnight at 37 C. The next day, bacteria are selected from 1) the longest time point with viable bacteria and 2) from the longest time point at the highest dilution. All the bacteria on the plate from the longest time point and the highest dilution are pooled, grown overnight (approx. 109 CFU/ml) and reinjected at the original concentration, and reisolated using the times and plating as above. The process may then be repeated. Individual bacteria from the plate from the longest time point and the highest dilution are then individually tested and compared to other bacteria from the same plate, and to the original VNP20009. Bacteria with at least a 30% increase, more preferably a 50% increase, and more preferably a 100% increase, and more preferably a greater than 100% increase are useful for antitumor studies (Pawelek et al., 1997). The above process may be repeated with a weight-adjusted dose, for rats, guinea pigs, rabbits, dogs, cats, pigs, monkeys or human volunteers. The process may also be scaled for the blood volume of a mouse (approx. 3 ml) to use of ex vivo human blood in vivo using sizes dependent upon availability and convenience. Ex vivo blood studies may also be performed, for example, in vacutainers, or in a chemostat using continuous fresh venous blood.
Example 7
Selection of Bacteria with Increased Survival in Blood with High CO2
Bacteria with increased survival in blood with high CO2 are selected from natural populations, mutagenized populations, suppressed strains, partially suppressed strains, as described above. By way of specific example, strains with improved serum half-life may be selected for starting with the clinical strain VNP20009.
VNP20009 are injected into a 20 g mouse at 1×106 CFU/mouse, and the mice are exposed to carbogen (oxygen; 70% CO2 30%, or variations thereof). Bacteria are periodically sampled from blood, at 15 min, 30 min, 60 min, 120 min, 240 min, 480 min, 960 min, 1920 min and plated by serial dilutions of 100-10−6 and incubated overnight at 37 C. The next day, bacteria are selected from 1) the longest time point with viable bacteria and 2) from the longest time point at the highest dilution. All the bacteria on the plate from the longest time point and the highest dilution are pooled, grown overnight (approx. 109 CFU/ml) and reinjected at the original concentration, and reisolated using the times and plating as above. The process may then be repeated. Individual bacteria from the plate from the longest time point and the highest dilution are then individually tested and compared to other bacteria from the same plate, and to the original VNP20009. Bacteria with at least a 30% increase, more preferably a 50% increase, and more preferably a 100% increase, and more preferably a greater than 100% increase are useful for antitumor studies (Pawelek et al., 1997). The above process may be repeated with a weight-adjusted dose, for rats, guinea pigs, rabbits, dogs, cats, pigs, monkeys or human volunteers. The process may also be scaled for the blood volume of a mouse (approx. 3 ml) to use of ex vivo human blood in vivo using sizes dependent upon availability and convenience. Ex vivo blood studies may also be performed, for example, in vacutainers, or in a chemostat using continuous fresh venous blood, and blood exposed to carbogen.
Example 8
Pharmaceutically Acceptable Formulations
Pharmaceutically acceptable formulations may be provided for delivery by other various routes e.g. by intramuscular injection, subcutaneous delivery, by intranasal delivery (e.g. WO 00/47222, U.S. Pat. No. 6,635,246), intradermal delivery (e.g. WO02/074336, WO02/067983, WO02/087494, WO02/0832149 WO04/016281, each of which is expressly incorporated herein by reference it its entirety) by transdermal delivery, by transcutaneous delivery, by topical routes, etc. Injection may involve a needle (including a microneedle), or may be needle-free. See, e.g., U.S. Pat. Nos. 7,452,531, 7,354,592, 6,962,696, 6,923,972, 6,863,894, 6,685,935, 6,475,482, 6,447,784, 6,190,657, 6,080,849 and US Pub. 2003/0059400, each of which is expressly incorporated herein by reference.
Bacterial vector vaccines are known, and similar techniqaues may be used for the present bacteria as for bacterial vaccine vectors (U.S. Pat. No. 6,500,419, Curtiss, In: New Generation Vaccines: The Molecular Approach, Ed., Marcel Dekker, Inc., New York, N.Y., pages 161-188 and 269-288 (1989); and Mims et al, In: Medical Microbiology, Eds., Mosby-Year Book Europe Ltd., London (1993)). These known vaccines can enter the host, either orally, intranasally or parenterally. Once gaining access to the host, the bacterial vector vaccines express an engineered prokaryotic expression cassette contained therein that encodes a foreign antigen(s). Foreign antigens can be any protein (or part of a protein) or combination thereof from a bacterial, viral, or parasitic pathogen that has vaccine properties (New Generation Vaccines: The Molecular Approach, supra; Vaccines and Immunotherapy, supra; Hilleman, Dev. Biol. Stand., 82:3-20 (1994); Formal et al, Infect. Immun. 34:746-751 (1981); Gonzalez et al, J. Infect. Dis., 169:927-931 (1994); Stevenson et al, FEMS Lett., 28:317-320 (1985); Aggarwal et al, J. Exp. Med., 172:1083-1090 (1990); Hone et al, Microbial. Path., 5:407-418 (1988); Flynn et al, Mol. Microbiol., 4:2111-2118 (1990); Walker et al, Infect. Immun., 60:4260-4268 (1992); Cardenas et al, Vacc., 11:126-135 (1993); Curtiss et al, Dev. Biol. Stand., 82:23-33 (1994); Simonet et al, Infect. Immun., 62:863-867 (1994); Charbit et al, Vacc., 11:1221-1228 (1993); Turner et al, Infect. Immun., 61:5374-5380 (1993); Schodel et al, Infect. Immun., 62:1669-1676 (1994); Schodel et al, J. Immunol., 145:4317-4321 (1990); Stabel et al, Infect. Immun., 59:2941-2947 (1991); Brown, J. Infect. Dis., 155:86-92 (1987); Doggett et al, Infect. Immun., 61:1859-1866 (1993); Brett et al, Immunol., 80:306-312 (1993); Yang et al, J. Immunol., 145:2281-2285 (1990); Gao et al, Infect. Immun., 60:3780-3789 (1992); and Chatfield et al, Bio/Technology, 10:888-892 (1992)). Delivery of the foreign antigen to the host tissue using bacterial vector vaccines results in host immune responses against the foreign antigen, which provide protection against the pathogen from which the foreign antigen originates (Mims, The Pathogenesis of Infectious Disease, Academic Press, London (1987); and New Generation Vaccines: The Molecular Approach, supra). See also: Formal et al, Infect. Immun., 34:746-751 (1981); Wick et al, Infect. Immun., 62:4542-4548 (1994)); Hone et al, Vaccine, 9:810-816 (1991); Tacket et al, Infect. Immun., 60:536-541 (1992); Hone et al, J. Clin. Invest., 90:412-420 (1992); Chatfield et al, Vaccine, 10:8-11 (1992); Tacket et al, Vaccine, 10:443-446 (1992); van Damme et al, Gastroenterol., 103:520-531 (1992) (Yersinia pestis), Noriega et al, Infect. Immun., 62:5168-5172 (1994)(Shigella spp), Levine et al, In: Vibrio cholerae, Molecular to Global Perspectives, Wachsmuth et al, Eds, ASM Press, Washington, D.C., pages 395-414 (1994)(Vibrio cholerae), Lagranderie et al, Vaccine, 11:1283-1290 (1993); Flynn, Cell. Molec. Biol., 40(Supp1.1):31-36 (1994)(Mycobacterium strain BCG), Schafer et al, J. Immunol., 149:53-59 (1992)(Listeria monocytogenes), each of which is expressly incorporated herein by reference.
The bacteria are generally administered along with a pharmaceutically acceptable carrier and/or diluent. The particular pharmaceutically acceptable carrier an/or diluent employed is not critical to the present invention unless otherwise specific herein (or in a respective incorporated referenced relevant to the issue). Examples of diluents include a phosphate buffered saline, buffer for buffering against gastric acid in the stomach, such as citrate buffer (pH 7.0) containing sucrose, bicarbonate buffer (pH 7.0) alone (Levine et al, J. Clin. Invest., 79:888-902 (1987); and Black et al J. Infect. Dis., 155:1260-1265 (1987), expressly incorporated herein by reference), or bicarbonate buffer (pH 7.0) containing ascorbic acid, lactose, and optionally aspartame (Levine et al, Lancet, 11:467-470 (1988), expressly incorporated herein by reference). Examples of carriers include proteins, e.g., as found in skim milk, sugars, e.g., sucrose, or polyvinylpyrrolidone. Typically these carriers would be used at a concentration of about 0.1-30% (w/v) but preferably at a range of 1-10% (w/v).
Set forth below are other pharmaceutically acceptable carriers or diluents which may be used for delivery specific routes. Any such carrier or diluent can be used for administration of the bacteria of the invention, so long as the bacteria are still capable of invading a target cell. In vitro or in vivo tests for invasiveness can be performed to determine appropriate diluents and carriers. The compositions of the invention can be formulated for a variety of types of administration, including systemic and topical or localized administration. Lyophilized forms are also included, so long as the bacteria are invasive upon contact with a target cell or upon administration to the subject. Techniques and formulations generally may be found in Remmington's Pharmaceutical Sciences, Meade Publishing Co., Easton, Pa., expressly incorporated herein by reference in its entirety. For systemic administration, injection is preferred, including intramuscular, intravenous, intraperitoneal, and subcutaneous. For injection, the composition, e.g., bacteria, of the invention can be formulated in liquid solutions, preferably in physiologically compatible buffers such as Hank's solution or Ringer's solution.
For oral administration, the pharmaceutical compositions may take the form of, for example, tablets or capsules prepared by conventional means with pharmaceutically acceptable excipients such as binding agents (e.g., pregelatinised maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose); fillers (e.g., lactose, microcrystalline cellulose or calcium hydrogen phosphate); lubricants (e.g., magnesium stearate, talc or silica); disintegrants (e.g., potato starch or sodium starch glycolate); or wetting agents (e.g., sodium lauryl sulphate). The tablets may be coated by methods well known in the art. Liquid preparations for oral administration may take the form of, for example, solutions, syrups or suspensions, or they may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents (e.g., sorbitol syrup, cellulose derivatives or hydrogenated edible fats); emulsifying agents (e.g., lecithin or acacia); non-aqueous vehicles (e.g., almond oil, oily esters, ethyl alcohol or fractionated vegetable oils); and preservatives (e.g., methyl or propyl-p-hydroxybenzoates or sorbic acid). The preparations may also contain buffer salts, flavoring, coloring and sweetening agents as appropriate.
Preparations for oral administration may be suitably formulated to give controlled release of the active compound. For buccal administration the compositions may take the form of tablets or lozenges formulated in conventional manner.
For administration by inhalation, the pharmaceutical compositions for use according to the present invention are conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebuliser, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit may be determined by providing a valve to deliver a metered amount. Capsules and cartridges of e.g. gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of the composition, e.g., bacteria, and a suitable powder base such as lactose or starch.
The pharmaceutical compositions may be formulated for parenteral administration by injection, e.g., by bolus injection or continuous infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use.
The pharmaceutical compositions may also be formulated in rectal, intravaginal or intraurethral compositions such as suppositories or retention enemas, e.g., containing conventional suppository bases such as cocoa butter or other glycerides.
See also U.S. Pat. No. 6,962,696, expressly incorporated herein by reference in its entirety.
The present invention provides a pharmaceutical composition comprising a pharmaceutically acceptable carrier and an attenuated tumor-targeted bacteria comprising one or more nucleic acid molecules encoding one or more primary effector molecules operably linked to one or more appropriate promoters. The present invention provides a pharmaceutical composition comprising a pharmaceutically acceptable carrier and an attenuated tumor-targeted bacteria comprising one or more nucleic acid molecules encoding one or more primary effector molecules and one or more secondary effector molecules operably linked to one or more appropriate promoters.
The present invention provides a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a bacteria.
In a specific embodiment, the term “pharmaceutically acceptable” means approved by a regulatory agency of the Federal or a state government or listed in the U.S. Pharmacopeia or other generally recognized pharmacopeia for use in animals, and more particularly in humans. The term “carrier” refers to a diluent, adjuvant, excipient, or vehicle with which the therapeutic is administered. Such pharmaceutical carriers can be sterile liquids, such as water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil, olive oil, and the like. Saline is a preferred carrier when the pharmaceutical composition is administered intravenously. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid carriers, particularly for injectable solutions. Suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol and the like. The composition, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. These compositions can take the form of solutions, suspensions, emulsion, tablets, pills, capsules, powders, sustained-release formulations and the like. Oral formulation can include standard carriers such as pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, etc. Examples of suitable pharmaceutical carriers are described in “Remington's Pharmaceutical Sciences” by E. W. Martin. Such compositions will contain a therapeutically effective amount of the therapeutic attenuated tumor-targeted bacteria, in purified form, together with a suitable amount of carrier so as to provide the form for proper administration to the patient. The formulation should suit the mode of administration.
In a preferred embodiment, the composition is formulated in accordance with routine procedures as a pharmaceutical composition adapted for intravenous administration to human beings. Typically, compositions for intravenous administration are solutions in sterile isotonic aqueous buffer. Where necessary, the composition may also include a suspending agent and a local anesthetic such as lignocaine to ease pain at the site of the injection. Generally, the ingredients are supplied either separately or mixed together in unit dosage form, for example, as a dry lyophilized powder or water free concentrate in a hermetically sealed container such as an ampoule or sachette indicating the quantity of active agent. Where the composition is to be administered by infusion, it can be dispensed with an infusion bottle containing sterile pharmaceutical grade water or saline. Where the composition is administered by injection, an ampoule of sterile water for injection or saline can be provided so that the ingredients may be mixed prior to administration.
The amount of the pharmaceutical composition of the invention which will be effective in the treatment or prevention of a solid tumor cancer will depend on the nature of the cancer, and can be determined by standard clinical techniques. In addition, in vitro assays may optionally be employed to help identify optimal dosage ranges. The precise dose to be employed in the formulation will also depend on the route of administration, and the seriousness of the cancer, and should be decided according to the judgment of the practitioner and each patient's circumstances. However, suitable dosage ranges are generally from about 1.0 c.f.u./kg to about 1×1010 c.f.u./kg; optionally from about 1.0 c.f.u./kg to about 1×108 c.f.u./kg; optionally from about 1×102 c.f.u./kg to about 1×108 c.f.u./kg; optionally from about 1 104 c.f.u./kg to about 1×108 c.f.u./kg; and optionally from about 1×104 c.f.u./kg to about 1×1010 c.f.u./kg. Effective doses may be extrapolated from dose-response curves derived from in vitro or animal model test systems.
Various delivery systems are known and can be used to administer a pharmaceutical composition of the present invention. Methods of introduction include but are not limited to intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intrathecal, intranasal, epidural, and oral routes. Methods of introduction may also be intra-tumoral (e.g., by direct administration into the area of the tumor).
The compositions may be administered by any convenient route, for example by infusion or bolus injection, by absorption through epithelial or mucocutaneous linings (e.g., oral mucosa, rectal and intestinal-mucosa, etc.) and may be administered together with other biologically active agents. Administration can be systemic or local. In addition, it may be desirable to introduce the pharmaceutical compositions of the invention into the central nervous system by any suitable route, including intraventricular and intrathecal injection; intraventricular injection may be facilitated by an intraventricular catheter, for example, attached to a reservoir, such as an Ommaya reservoir. Pulmonary administration can also be employed, e.g., by use of an inhaler or nebulizer, and formulation with an aerosolizing agent.
In a specific embodiment, it may be desirable to administer the pharmaceutical compositions of the invention locally to the area in need of treatment; this may be achieved by, for example, and not by way of limitation, local infusion during surgery, by injection, by means of a catheter, or by means of an implant, said implant being of a porous, non-porous, or gelatinous material, including membranes, such as sialastic membranes, or fibers. In one embodiment, administration can be by direct injection at the site (or former site) of a malignant tumor or neoplastic or pre-neoplastic tissue.
The attenuated tumor-targeted bacteria comprising one or more primary effector molecules and optionally, one or more secondary effector molecules may be delivered in a controlled release system. The attenuated tumor-targeted bacteria comprising one or more fusion proteins of the invention and optionally, one or more effector molecules may also be delivered in a controlled release system. In one embodiment, a pump may be used (see Langer, supra; Sefton, CRC Crit. Ref. Biomed. Eng. 14:201 (1987); Buchwald et al., 1980, Surgery 88:507; and Saudek et al., 1989, N. Engl. J. Med. 321:574), expressly incorporated herein by reference in their entirety. In another embodiment, polymeric materials can be used (see Medical Applications of Controlled Release, Langer and Wise (eds.), CRC Pres., Boca Raton, Fla. (1974); Controlled Drug Bioavailability, Drug Product Design and Performance, Smolen and Ball (eds.), Wiley, New York (1984); Ranger and Peppas, J. Macromol. Sci. Rev. Macromol. Chem: 23:61 (1983); see also Levy et al., 1985, Science 228:190; During et al., 1989, Ann. Neurol. 25:351; and Howard et al., 1989, J. Neurosurg. 71:105, expressly incorporated herein by reference in their entirety). In yet another embodiment, a controlled release system can be placed in proximity of the therapeutic target, i.e., the brain, thus requiring only a fraction of the systemic dose (see, e.g., Goodson, in Medical Applications of Controlled Release, supra, vol. 2, pp. 115-138 (1984), expressly incorporated by reference in its entirety).
Other controlled release systems are discussed in the review by Langer (1990, Science 249:1527-1533, expressly incorporated herein by reference in its entirety) and may be used in connection with the administration of the attenuated tumor-targeted bacteria comprising one or more primary effector molecule(s) and optionally, one or more secondary effector molecule(s).
The invention also provides a pharmaceutical pack or kit comprising one or more containers filled with one or more of the ingredients of the pharmaceutical compositions of the invention. Optionally associated with such container(s) can be a notice in the form prescribed by governmental agency regulating the manufacture, use or sale of pharmaceuticals or biological products, which notice reflects approval by the agency of manufacture, use or sale for human administration.
The present invention also provides methods for treating a solid tumor comprising administering to a human or animal in need thereof, a pharmaceutical composition of the invention and at least one other known cancer therapy. In a specific embodiment, a human or animal with a solid tumor cancer is administered a pharmaceutical composition of the invention and at least one chemotherapeutic agent. Examples of chemotherapeutic agents include, but are not limited to, cisplatin, ifosfamide, taxanes such as taxol and paclitaxol, topoisomerase I inhibitors (e.g., CPT-11, topotecan, 9-AC, and GG-211), gemcitabine, vinorelbine, oxaliplatin, 5-fluorouracil (5-FU), leucovorin, vinorelbine, temodal, cytochalasin B, gramicidin D, emetine, mitomycin, etoposide, tenoposide, vincristine, vinblastine, colchicin, doxorubicin, daunorubicin, dihydroxy anthracin dione, mitoxantrone, mithramycin, actinomycin D, 1-dehydrotestosterone, glucocorticoids, procaine, tetracaine, lidocaine, propranolol, and puromycin homologs, and cytoxan.
The present invention includes the sequential or concomitant administration of pharmaceutical composition of the invention and an anti-cancer agent such as a chemotherapeutic agent. In a specific embodiment, the pharmaceutical composition of the invention is administered prior to (e.g., 2 hours, 6 hours, 12 hours, 1 day, 4 days, 6 days, 12 days, 14 days, 1 month or several months before) the administration of the anti-cancer agent. In another specific embodiment, the pharmaceutical composition of the invention is administered subsequent to (e.g., 2 hours, 6 hours, 12 hours, 1 day, 4 days, 6 days, 12 days, 14 days, 1 month or several months after) the administration of an anti-cancer agent. In a specific embodiment, the pharmaceutical composition of the invention is administered concomitantly with an anti-cancer agent. The invention encompasses combinations of anti-cancer agents and attenuated tumor-targeted bacteria engineered to express one or more nucleic acid molecules encoding one or more effector molecules and/or fusion proteins that are additive or synergistic.
The invention also encompasses combinations of anti-cancer agents and attenuated tumor-targeted bacteria engineered to express one or more nucleic acid molecules encoding one or more effector molecules and/or fusion proteins that have different sites of action. Such a combination provides an improved therapy based on the dual action of these therapeutics whether the combination is synergistic or additive. Thus, the novel combinational therapy of the present invention yields improved efficacy over either agent used as a single-agent therapy.
In one embodiment, an animal with a solid tumor cancer is administered a pharmaceutical composition of the invention and treated with radiation therapy (e.g., gamma radiation or x-ray radiation). In a specific embodiment, the invention provides a method to treat or prevent cancer that has shown to be refractory to radiation therapy. The pharmaceutical composition may be administered concurrently with radiation therapy. Alternatively, radiation therapy may be administered subsequent to administration of a pharmaceutical composition of the invention, preferably at least an hour, five hours, 12 hours, a day, a week, a month, more preferably several months (e.g., up to three months), subsequent to administration of a pharmaceutical composition.
The radiation therapy administered prior to, concurrently with, or subsequent to the administration of the pharmaceutical composition of the invention can be administered by any method known in the art. Any radiation therapy protocol can be used depending upon the type of cancer to be treated. For example, but not by way of limitation, x-ray radiation can be administered; in particular, high-energy megavoltage (radiation of greater that 1 MeV energy) can be used for deep tumors, and electron beam and orthovoltage x-ray radiation can be used for skin cancers. Gamma ray emitting radioisotopes, such as radioactive isotopes of radium, cobalt and other elements may also be administered to expose tissues to radiation.
Additionally, the invention also provides methods of treatment of cancer with a Pharmaceutical composition as an alternative to radiation therapy where the radiation therapy has proven or may prove too toxic, i.e., results in unacceptable or unbearable side effects, for the subject being treated.
The pharmaceutical compositions of the invention are preferably tested in vitro, and then in vivo for the desired therapeutic or prophylactic activity, prior to use in humans. For example, in vitro assays which can be used to determine whether administration of a specific pharmaceutical composition is indicated, include in vitro cell culture assays in which a patient tissue sample is grown in culture, and exposed to or otherwise administered a pharmaceutical composition, and the effect of such composition upon the tissue sample is observed.
Pharmaceutical compositions of the invention can be tested for their ability to augment activated immune cells by contacting immune cells with a test pharmaceutical composition or a control and determining the ability of the test pharmaceutical composition to modulate (e.g., increase) the biological activity of the immune cells. The ability of a test composition to modulate the biological activity of immune cells can be assessed by detecting the expression of cytokines or antigens, detecting the proliferation of immune cells, detecting the activation of signaling molecules, detecting the effector function of immune cells, or detecting the differentiation of immune cells. Techniques known to those of skill in the art can be used for measuring these activities. For example, cellular proliferation can be assayed by 3H-thymidine incorporation assays and trypan blue cell counts. Cytokine and antigen expression can be assayed, for example, by immunoassays including, but are not limited to, competitive and non-competitive assay systems using techniques such as western blots, immunohisto-chemistry radioimmunoassays, ELISA (enzyme linked immunosorbent assay), “sandwich” immunoassays, immunoprecipitation assays, precipitin reactions, gel diffusion precipitin reactions, immunodiffusion assays, agglutination assays, complement-fixation assays, immunoradiometric assays, fluorescent immunoassays, protein A, immunoassays and FACS analysis. The activation of signaling molecules can be assayed, for example, by kinase assays and electromobility shift assays (EMSAs). The effector function of T-cells can be measured, for example, by a 51Cr-release assay (see, e.g., Palladino et al., 1987, Cancer Res. 47:5074-5079 and Blachere et al., 1993, J. Immunotherapy 14:352-356, expressly incorporated herein by reference).
Pharmaceutical compositions of the invention can be tested for their ability to reduce tumor formation in animals suffering from cancer. Pharmaceutical compositions of the invention can also be tested for their ability to alleviate of one or more symptoms associated with a solid tumor cancer. Further, pharmaceutical compositions of the invention can be tested for their ability to increase the survival period of patients suffering from a solid tumor cancer. Techniques known to those of skill in the art can be used to analyze the function of the pharmaceutical compostions of the invention in animals.
In various specific embodiments, in vitro assays can be carried out with representative cells of cell types involved in a solid tumor cancer, to determine if a pharmaceutical composition of the invention has a desired effect upon such cell types.
Pharmaceutical compositions of the invention for use in therapy can be tested in suitable animal model systems prior to testing in humans, including but not limited to rats, mice, chicken, cows, monkeys, pigs, dogs, rabbits, etc. For in vivo testing, prior to administration to humans, any animal model system known in the art may be used.
Each reference cited herein is expressly incorporated herein in its entirety. Such references provide examples representing aspects of the invention, uses of the invention, disclosure of the context of the invention and its use and application. The various aspects disclosed herein, including subject matter incorporated herein by reference, may be employed, in combination or subcombination and in various permutations, consistent with the claims.
The invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiment is to be considered in all respects only illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather by the foregoing description. All changes that fall within the meaning and range of equivalency of the claims are to be embraced within their scope.

## Claims

1. A live genetically engineered Salmonella bacterium, comprising:
at least one first gene, producing at least one secreted first gene product comprising a sialic acid O-acyl transferase under control of at least one heterologous first inducible promoter; and
at least one second gene, producing a secreted functional antitumor enzyme gene product under control of a second heterologous inducible promoter,
the at least one first gene being distinct from the at least one second gene,
the at least one heterologous first inducible promoter being distinct from the at least one heterologous second inducible promoter;
the live genetically engineered Salmonella bacterium being adapted for:
administration to a human or animal and colonization of at least one tissue under non-lethal conditions,
after colonization of the at least one tissue, secretion of the sialic acid O-acyl transferase under control of the first inducible promoter, for action on external components of the live genetically engineered Salmonella bacterium, and
after colonization of the at least one tissue, secretion of the secreted functional antitumor enzyme gene product under control of the second inducible promoter, for action against tumor cells.

2. The live genetically engineered Salmonella bacterium according to claim 1, wherein the at least one first gene further produces O-antigen transferase.

3. The live genetically engineered Salmonella bacterium according to claim 1, wherein the secreted the functional antitumor gene product comprises tyrosinase which is secreted from the live genetically engineered Salmonella bacterium in active form.

4. The live genetically engineered Salmonella bacterium according to claim 1, wherein the secreted the functional antitumor gene product comprises an amino-acid degrading enzyme which is secreted from the live genetically engineered Salmonella bacterium in active form and has anti-tumor activity against human or animal tumors colonized by the live genetically engineered Salmonella bacterium.

5. The live genetically engineered Salmonella bacterium according to claim 1, wherein the secreted the functional antitumor gene product comprises at least one enzyme selected from the group consisting of tryptophanase and asparaginase, which is secreted from the live genetically engineered Salmonella bacterium in active form.

6. The live genetically engineered Salmonella bacterium according to claim 1, wherein the first inducible promoter comprises MarA, which is induced by presence of acetyl salicylic acid.

7. The live genetically engineered Salmonella bacterium according to claim 1, wherein the first inducible promoter is responsive to at least one of tet, arabinose, hypoxia, a cellular SOS response promoter, X-rays, and mitomycin.

8. The live genetically engineered Salmonella bacterium according to claim 1, wherein the at least first gene product comprises a plurality of inducible gene products having respectively different first inducible promoters.

9. The live genetically engineered Salmonella bacterium according to claim 1, wherein the at least one heterologous first inducible promoter comprises a plurality of different heterologous inducible promoters, having respectively different pharmacological inducers which are not naturally found in human tissue, effective to promote a plurality of different ones of the at least one first gene.

10. The live genetically engineered Salmonella bacterium according to claim 1, wherein the at least one first gene comprises a plurality of first genes producing a plurality of respectively different secreted first gene products, under control of a plurality of respective different heterologous first inducible promoters, induced by respectively different pharmacological inducer agents not naturally found in humans, to thereby provide the live genetically engineered Salmonella bacterium having a plurality of different surface antigen patterns under control of a selective presence of the different pharmacological inducer agents.

11. The live genetically engineered Salmonella bacterium according to claim 1, wherein the live genetically engineered Salmonella bacterium has a selective tropism for at least one type of tumor in a human or animal, and the secreted functional antitumor enzyme gene product is effective for treating the at least one type of tumor, the live genetically engineered Salmonella bacterium being provided within a pharmaceutically acceptable formulation for administration to the human or animal.

12. The live genetically engineered Salmonella bacterium according to claim 1, wherein the live genetically engineered Salmonella bacterium is provided in a pharmaceutically acceptable formulation suitable for administration to a human or animal, and the at least one secreted first gene product is effective for increasing a serum half-life of the live genetically engineered Salmonella bacterium after administration to the human or animal in the pharmaceutically acceptable formulation as compared to the live genetically engineered Salmonella bacterium without the at least one secreted first gene product.

13. The live genetically engineered Salmonella bacterium according to claim 1, wherein the at least one heterologous first inducible promoter comprises a single promoter effective to promote a plurality of first genes to produce a plurality of respectively different secreted first gene products.

14. The live genetically engineered Salmonella bacterium according to claim 1, wherein the at least one heterologous first inducible promoter comprises a regulon comprising a mar promoter/operator region, a MarR negative regulator, a MarA positive regulator, upstream of a start codon, for promoting expression of an rfb cluster.

15. The live genetically engineered Salmonella bacterium according to claim 1, further comprising at least one third heterologous gene producing a secreted heterologous protease inhibitor.

16. The live genetically engineered Salmonella bacterium according to claim 1, having a maximum size of about 650 nm.

17. The live genetically engineered Salmonella bacterium according to claim 1, having a width of less than 401 nm.

18. The live genetically engineered Salmonella bacterium according to claim 1, wherein the at least one first gene product further comprises Lic3A, lic3B and sigA.

19. The live genetically engineered Salmonella bacterium according to claim 2, wherein the at least one first gene product is effective for producing a plurality of different 0 antigens.

20. The live genetically engineered Salmonella bacterium according to claim 1, selected to have higher CO2 resistance than wild type Salmonella.