# Patent

## Title
FGFR-Fc fusion proteins and the use thereof

## Abstract

The present invention belongs to the field of biotechnology and relates to the treatment of diseases, especially the treatment of FGF overexpression-related diseases. Particularly, the present invention relates to FGFR-Fc fusion proteins and the use thereof in the treatment of angiogenesis regulation-related diseases. More particularly, the present invention relates to isolated soluble FGFR-Fc fusion proteins and their applications in manufacture of the medicament for the treatment of angiogenesis regulation-related diseases.

## Background
CROSS-REFERENCE TO A RELATED APPLICATION
The present application is a continuation-in-part of International Application PCT/CN2012/075706, filed May 18, 2012; which claims priority to Chinese Application No. 2011 10132218.9, filed May 20, 2011; both of which are incorporated by reference herein in their entirety, including any figures, tables, nucleic acid sequences, amino acid sequences, or drawings.
The Sequence Listing for this application is labeled “SeqList-10 Jun. 14-ST25.txt which was created on Jun. 10, 2014 and is 105 KB. The entire content of the sequence listing is incorporated herein by reference in its entirety.


FIELD OF THE INVENTION
The present invention belongs to the field of biotechnology and relates to the treatment of diseases, especially the treatment of FGF overexpression-related diseases. Particularly, the present invention relates to FGFR-Fc fusion proteins and the use thereof in the treatment of angiogenesis regulation-related diseases. More particularly, the present invention relates to isolated soluble FGFR-Fc fusion proteins and their applications in manufacture of the medicament for the treatment of angiogenesis regulation-related diseases.
BACKGROUND OF THE INVENTION
Angiogenesis is one of the primary factors resulting in the growth and metastasis of malignant tumors [1]. The process of angiogenesis is regulated by many factors, among which some factors promote angiogenesis, while some factors inhibit angiogenesis, and as a result, the regulation of angiogenesis is a very complicated dynamic process [2]. Anti-angiogenesis treatment is intended to control the growth of a tumor by blocking angiogenic stimulating factors or preventing angiogenesis in the tumor using angiogenesis inhibitors. At present, a large amount of angiogenic stimulating factors are known, such as, for example, vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), hepatocyte growth factor (HGF) etc. which may stimulate the division and differentiation of vascular endothelial cells and the morphogenesis of blood vessels. Among these factors mentioned above, it is now known that VEGF is the most angiogenesis-specific and the most effective growth factor [3, 4].
In a hypoxic environment inside tumor tissue, VEGFs are secreted by the tumor cells, which induce the division and migration of vascular endotheliocytes, resulting in the establishment of a tumor vascular network. It has been demonstrated that the inhibition of VEGF may prevent angiogenesis, and further inhibit the growth of tumor. For this reason, VEGF and its receptors are important targets for anti-angiogenesis medicaments.
At present, anti-angiogenesis medicaments demonstrated in clinical trials to have efficacy include Bevacizumab (under the trade name of Avastin), which is able to block VEGF directly and inhibit the tumor angiogenesis. Bevacizumab was approved for marketing by the FDA in 2004, and as a first-line drug for rectal cancer, it is the first marketing-approved drug that plays a role in anticarcinogenesis by inhibiting angiogenesis. Avastin is a humanized anti-VEGF monoclonal antibody, which is produced by Genentech. In a large-scale Phase III clinical trial, the combined therapy by Avastin and chemotherapy may significantly extend the survival time of the patients suffered from many kinds of cancers, including rectal cancer, lung cancer, breast cancer and renal cancer. [5, 6] The clinical success of Avastin is a landmark, demonstrating that the anti-angiogenesis treatment using tumor vascular system as the target is a clinically effective measure and provide a new path for the tumor treatment.
Besides Avastin, several drugs for anti-VEGF signaling are also in the late phase of human clinical trial and are expected for clinical application in the next several years. Among others, Aflibercept (also called as VEGF-Trap), developed by the Regeneron and Sanofi-Aventis, is now in Phase III clinical trial[7]. An anti-VEGF receptor II (VEGFR2) monoclonal antibody drug IMC-1121B (Imclone) is also in Phase III clinical trial[8]. The amino acid sequence of VEGFR2 is provided in SEQ ID NO: 3 and the nucleotide sequence of VEGFR2 mRNA is provided in SEQ ID NO: 6.
Great progress has been achieved in the clinical treatment of tumor using anti-VEGF medicament, however, it has also been shown by the clinical trial that the anti-VEGF treatment are also considerably limited. From the point of the effect of tumor treatment, Avastin may extend the half survival time of the colon cancer patient for about 3-4 months [9, 10], and extend the half survival time of the breast cancer patient for about 7-8 months [11], and thus, Avastin cannot effectively inhibit the growth of tumor blood vessel over the long term.
The primary causes resulting in the failure of anti-VEGF treatment or the appearance of resistance may depend on the regulation of tumor angiogenesis by a plurality of factors. Although VEGF plays an important role in angiogenesis, it is not the only angiogenesis stimulating factor. Meanwhile, owing to the heterogeneity of tumor cells, the complexity of tumor microenvironment and the compensatory response mechanism of body, when the activity of VEGF is inhibited for a long period of time, other angiogenesis stimulating factors would be expressed [12], and thus the growth of tumor blood vessel is no longer dependent on VEGF signaling path.
The variation of angiogenesis factors expressed by the tumor was studied during anti-VEGFR2 treatment for pancreatic tumor by Prof Hanahan's group (University of California, San Francisco, US), indicating that the expression of several genes changed during anti-VEGF treatment, in which the expression of FGF-2 significantly increased. It has been shown that the expression of FGF, especially FGF-2, increased significantly in the tumor resistant to anti-VEGF treatment so that angiogenesis was activated again and the tumor repopulation was inhibited after blocking FGF signal pathway [13]. It may be seen that the over-expression of FGF-2 is closely related to the ability of tumor to escape from anti-VEGF treatment.
Fibroblast growth factor (FGF) is a growth factor family for heparin-binding, and there are 22 family members (FGF 1-14, 16-23) in mammals. FGF plays an important role in many biological functions, for example, cell proliferation, differentiation, migration, angiogenesis and tumorigenesis. Fibroblast growth factor receptor (FGFR) is the receptor that binds the family members of fibroblast growth factor. FGF may bind FGFR and activate the downstream signal pathway, which plays an important role in a physiological and pathological process, such as embryogenesis, development, vasculogenesis, vasodilatation, neuroregulation, ischemia protection, wound healing and tumorigenesis. [14, 15] It has been demonstrated that overexpression of FGF/FGFR in vivo is closely related to many diseases including tumors (such as fibroma, neuroglioma, melanoma, prostate carcinoma, lymphomata, leukaemia, urinary, and system cancer), skeletal system diseases (dwarfism, craniosynostosis, achondroplasia, and acanthosis nigricans) and renal failure. It has been reported that increased expression level of FGF and its receptor may directly promote the survival and proliferation of tumor cells, and the survival of hepatic carcinoma cells is significantly reduced by down-regulation of FGF by siRNA [22].
At present, few researches focus on the development of new anti-angiogenesis medicament using FGF and its receptor as the target in clinical trials. For example, FP-1039, a fusion protein composed of whole extracellular domain of human FGFR1 and human IgG1 Fc fragment, is developed by a US company Five Prime and now in volunteer recruitment stage of Phase I clinical trail. However, it has been suggested by researches of Wang and Olsen that the first Ig-like domain of the extracellular domain of human FGFR1 and the linking fragment between the first and the second Ig-like domain of the extracellular domain of human FGFR1 may inhibit binding of FGFR1 and FGF [20, 21].
The tertiary structure of a protein is closely related to its biological function. The FGF binding capacity is directly influenced differences among the conformations of each Ig-like domain of the extracellular domain of FGFR and the linking fragment. Different fusion proteins, composed of the FGFR extracellular domain fragments of various lengths and IgG Fc, are constructed by means of genetic engineering to obtain fusion proteins with different conformations, so that the fusion protein with high efficiency of FGF binding and biological activity can be screened.
There are four FGFR genes in mammals: fgfR1-fgfR4. Fibroblast growth factor receptor is composed of the extracellular domain, transmembrane domain and intracellular domain. There are many members in FGFR family, which have similar extracellular domain but vary in the ligand binding property and kinase domain. Their extracellular domains include three immunoglobulin-like (Ig-like) domains: the first Ig-like domain, the second Ig-like domain and the third Ig-like domain, and there is a sequence between the first and the second Ig-like domain, which is referred as the intermediate functional sequence of the Ig-like domain of FGFR (IFS for short herein) in this specification. The intermediate functional sequence may comprise one acidic amino acid segment, which is referred as acidic box (AB).
BRIEF SUMMARY
The present invention provides isolated soluble fusion proteins of fibroblast growth factor receptor (FGFR), which comprise: a part derived from an intermediate functional sequence (also referred to herein as IFS) of an Ig-like domain of FGFR, a second Ig-like domain (also referred to herein as D2) of FGFR, a third ig-like domain (also referred to herein as D3) of FGFR and an immunoglobulin Fc region.
In certain embodiments, the part derived from IFS contains no acidic box. In other embodiments, the IFS portion has the amino acid sequence of position 134 to position 162, position 145 to position 162, or position 151 to position 162 of SEQ ID NO: 1, or has an amino acid sequence sharing at least 70% identity with the amino acid sequence of position 134 to position 162, position 145 to position 162 or position 151 to position 162 of SEQ ID NO: 1.
The present invention further relates to a fusion protein, which comprises or consists of: the first Ig-like domain (also referred to herein as D1) of FGFR or a moiety thereof, a part derived from the intermediate functional sequence region of the Ig-like domain of FGFR, the second Ig-like domain of FGFR, the third Ig-like domain of FGFR, and an immunoglobulin Fc region.
Preferably, the D1 domain or a moiety thereof possesses:
the amino acid sequence corresponding to position 40 to position 118 of SEQ ID NO: 1, or an amino acid sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity with the sequence of position 40 to position 118 of SEQ ID NO: 1; or the amino acid sequence corresponding to position 77 to position 118 of SEQ ID NO: 1, or an amino acid sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity with the amino acid sequence of position 77 to position 118 of SEQ ID NO:1.
In one aspect, the present invention provides a fusion protein that comprises or consists of: the intermediate functional sequence region of the Ig-like domain of FGFR or a moiety thereof, the second Ig-like domain of FGFR, the third Ig-like domain of FGFR and immunoglobulin Fc region, wherein:
the second Ig-like domain of FGFR has the amino acid sequence corresponding to position 163 to position 247 of SEQ ID NO: 1, or an amino acid sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity with the amino acid sequence of position 163 to position 247 of SEQ ID NO: 1; and/or
the third Ig-like domain of FGFR has the amino acid sequence corresponding to position 270 to position 359 of SEQ ID NO: 1, or an amino acid sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity with the amino acid sequence of position 270 to position 359 of SEQ ID NO: 1.
The present invention further provides a fusion protein that comprises a region derived from the extracellular domain of FGFR and a immunoglobulin Fc region or composed thereof, wherein the region derived from the extracellular domain of FGFR:
(1) has the amino acid sequence indicated by positions 358-580 of SEQ ID NO: 9, positions 304-526 of SEQ ID NO: 10, positions 278-500 of SEQ ID NO: 11, positions 246-468 of SEQ ID NO: 12, positions 235-457 of SEQ ID NO: 13, positions 229-451 of SEQ ID NO: 14 or positions 224-446 of SEQ ID NO: 15, or the amino acid sequence encoded by the nucleotide sequence indicated by positions 1074-1740 of SEQ ID NO: 16, positions 912-1578 of SEQ ID NO: 17, positions 834-1500 of SEQ ID NO: 18, positions 738-1404 of SEQ ID NO: 19, positions 705-1371 of SEQ ID NO: 20, positions 687-1353 of SEQ ID NO: 21 and positions 672-1338 of SEQ ID NO: 22;
(2) comprises or consists of the amino acid sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity with the amino acid sequence indicated by positions 358-580 of SEQ ID NO: 9, positions 304-526 of SEQ ID NO: 10, positions 278-500 of SEQ ID NO: 11, positions 246-468 of SEQ ID NO: 12, positions 235-457 of SEQ ID NO: 13, positions 229-451 of SEQ ID NO: 14 or positions 224-446 of SEQ ID NO: 15; or
(3) comprises or consists of the amino acid sequence encoded by a nucleotide sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity with the nucleotide sequence indicated by positions 1074-1740 of SEQ ID NO: 16, positions 912-1578 of SEQ ID NO: 17, positions 834-1500 of SEQ ID NO: 18, positions 738-1404 of SEQ ID NO: 19, positions 705-1371 of SEQ ID NO: 20, positions 687-1353 of SEQ ID NO: 21 or positions 672-1338 of SEQ ID NO: 22.
The present invention further relates to a fusion protein, wherein the protein:
(1) comprises the amino acid sequence indicated by any one of SEQ ID NOs: 9-15, or an amino acid sequence encoded by the nucleotide sequence indicated by any one of SEQ ID NOs: 16-22;
(2) comprises or consists of the amino acid sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity, with the amino acid sequence indicated by any one of SEQ ID NOs: 9-15; or
(3) comprises or consists of the amino acid sequence encoded by the nucleotide sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity, with the nucleotide sequence indicated by any one of SEQ ID NOs: 16-22.
Preferably, in the fusion protein of the present invention, the immunoglobulin Fc region is human IgG1 Fc region, and more preferably, it comprises:
the amino acid sequence corresponding to SEQ ID NO: 7, or the amino acid sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity, with the amino acid sequence of SEQ ID NO: 7; or
the amino acid sequence encoded by the nucleotide sequence corresponding to SEQ ID NO: 8, or the amino acid sequence encoded by the nucleotide sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity, with the nucleotide sequence of SEQ ID NO: 8.
In one embodiment of the present invention, the immunoglobulin Fe region is located at the C-terminus of the fusion protein.
The present invention further provides a fusion protein precursor comprising a secretory signal peptide region, for example, VEGFR1 signal peptide region, and preferably, the secretory signal peptide region has the amino acid sequence of position 1 to position 26 of SEQ ID NO: 2 or the amino acid sequence encoded by the nucleotide sequence of SEQ ID NO: 23. Preferably, the signal peptide region is located at the N-terminus of the precursor. The nucleotide sequence of VEGFR1 mRNA is provided in SEQ ID NO: 5.
In another aspect of the present invention, an isolated nucleic acid molecule that encodes the fusion protein or the precursor of the fusion protein of the present invention is provided. Preferably, the nucleic acid molecule comprises the nucleotide sequence indicated by any one of SEQ ID NOs: 16-22.
The present invention provides a fusion protein that sequentially comprises from the N-terminus to the C-terminus: portions derived from IFR, D2, D3 and immunoglobulin Fc region.
The domains and/or regions involved in the fusion protein of the present invention can be linked directly and/or by a linker. In one embodiment, the region derived from the extracellular domain of FGFR and immunoglobulin Fc region are linked directly. In another embodiment, the region derived from the extracellular domain of FGFR and immunoglobulin Fc region are linked by a linker.
In one aspect, the fusion protein of the present invention inhibits angiogenesis. In another aspect, the fusion protein of the present invention binds FGF, preferably FGF2, in vivo and/or in vitro. In another aspect, the fusion protein of the present invention inhibits tumor cells directly.
The present invention further relates to an FGFR-Fc fusion protein that comprises a portion derived from the extracellular domain of FGFR and a portion derived from immunoglobulin Fc region. Particularly, the portion derived from the extracellular domain of FGFR is derived from the extracellular domain of FGFR1. Preferably, the immunoglobulin Fc region is a human immunoglobulin Fc region, for example, a human IgG1 Fc region. In one aspect of the present invention, the FGFR-Fc fusion protein of the present invention has the capacity of binding and/or antagonizing FGF, and thus, inhibit angiogenesis.
In the FGFR-Fc fusion protein of the present invention, the portion derived from the extracellular domain of FGFR may comprise one or more selected from the group consisting of: D1 domain or a moiety thereof, the portion derived from IFS, D2 domain or a moiety thereof and D3 domain or a moiety thereof.
In one embodiment, the part derived from the extracellular domain of FGFR may comprise D1 or a moiety thereof, the part derived from IFS, D2 domain and D3 domain.
In another embodiment, the part derived from the extracellular domain of FGFR may comprise the part derived from IFS, D2 domain and D3 domain, and preferably, the part derived from IFS has the amino acid sequence corresponding to position 134 to position 162, position 145 to position 162, or position 151 to position 162 of SEQ ID NO: 1.
In some embodiments, the FGFR-Fc fusion protein of the present invention contains no D1 or a moiety thereof. In some other embodiments, the FGFR-Fc fusion protein of the present invention contains no part from IFS other than the amino acid sequence corresponding to position 134 to position 162, position 145 to position 162, or position 151 to position 162 of SEQ ID NO: 1.
In some embodiments of the present invention, the order from the N-terminus to the C-terminus of each region and/or each domain involved in the FGFR-Fc fusion protein may be any order. In some other embodiments, the order can be as shown in FIG. 1. In some other embodiments, the order may be different from the order shown in FIG. 1.
In some embodiments, the FGFR-Fc fusion protein of the present invention further comprises one or more intrachain disulfide bonds, and preferably, comprises one or more intra-chain disulfide bonds in the Ig-like domain.
In one aspect of the present invention, the FGFR-Fc fusion protein can be produced by expression of the nucleic acid comprising the nucleotide sequence indicated by any one of SEQ ID NOs: 16-22 in a mammalian cell line. The mammalian cell line can be, for example, a CHO cell line.
In another aspect of the present invention, a vector comprising the nucleic acid molecule of the present invention is provided.
In another aspect of the present invention, cells, such as CHO cells, transfected by the vector are provided.
In another embodiment of the present invention, a pharmaceutical composition, which comprises the fusion protein, the nucleic acid molecule, the vector, or the cells of the present invention, as well as a pharmaceutically acceptable carrier, is also provided.
In another aspect, the present invention provides a method for producing the angiogenesis-inhibitory fusion protein, which is carried out by expressing the fusion protein of the present invention in prokaryotic cells or eukaryotic cells, especially, in mammalian cell lines.
The present invention further provides a method for producing the angiogenesis-inhibitory fusion protein, which is carried out by expressing the nucleic acid molecule of the present invention in a mammalian cell. The mammalian cell line can be, for example, a CHO cell line.
In another aspect of the present invention, a method for inhibition of angiogenesis is provided, which comprises administering, to a subject in need thereof, an angiogenesis-inhibiting effective amount of the FGFR-Fc fusion protein, the nucleic acid molecule encoding the protein, the vector comprising the nucleic acid molecule and/or a pharmaceutical composition comprising any one of these materials. Preferably, the method is carried out in a mammal.
In another aspect of the present invention, a method for the treatment and/or prevention of a tumor in a mammal is provided. This method comprises administering, to a need of such treatment, a therapeutically or preventively effective amount of the FGFR-Fc fusion protein, the nucleic acid molecule encoding the protein, the vector comprising the nucleic acid molecule, and/or a pharmaceutical composition comprising any one of these materials. Preferably, the tumor is a solid tumor.
In another aspect, the present invention provides a method for the treatment or prevention of ophthalmic angiogenesis-related diseases in mammals. This method comprises administering, to a subject in need of such treatment or prevention, a therapeutically or preventively effective amount of the FGFR-Fc fusion protein, the nucleic acid molecule encoding the protein, the vector comprising the nucleic acid molecule, and/or a pharmaceutical composition comprising any one of these materials. Preferably, the ophthalmic angiogenesis-related disease is age-related macular degeneration.
The present invention further relates to use of the FGFR-Fc fusion protein, the nucleic acid molecule encoding the protein, the vector comprising the nucleic acid molecule, and/or a pharmaceutical composition comprising any one mentioned above according to the present invention in the manufacture of a medicament for inhibiting angiogenesis.
Furthermore, the present invention further relates to use of the FGFR-Fc fusion protein, the nucleic acid molecule encoding the protein, the vector comprising the nucleic acid molecule, and/or a pharmaceutical composition comprising any one mentioned above according to the present invention in manufacture of a medicament for the treatment or prevention of angiogenesis-related diseases, and preferably, the angiogenesis-related disease is a tumor or ophthalmic angiogenesis-related disease.
In the disclosure, only some specific embodiments claimed for protection are illustrated by way of example, in which the technical features described in one or more technical proposals can be combined with any one or more technical proposals, and these technical proposals obtained by combination are also within the scope of this application, as if these technical proposals obtained by combination were already specifically described in the disclosure.
It should be understood that the description below is only illustrated by way of example for the technical solutions claimed for protection by the present invention, and not regarded as any limitation on these technical solutions. The protection scope of the present invention shall be defined by the claims as appended.



BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a structural representation of a FGFR1-Fc fusion protein. The FGFR1-Fc fusion protein is represented by a solid line, and a deleted amino acid is represented by a dashed line; the antibody-like domain is represented by a circle; different antibody-like domains are represented by numbers 1-3; a disulfide bond is represented by s s; human IgG1 Fc is represented by a grey box; VEGFR1 signal peptide is represented by SP; the acidic box sequence is represented by a box with the letters AB.
FIG. 2 shows a comparison of FGF-2 binding among various FGFR1-Fc fusion proteins. Binding of heparin (100 ng/mL) containing FGF-2 (50 ng/mL) or FGF-2 (50 ng/mL) alone to each FGFR1-Fc fusion protein (20 ng/mL) is detected by ELISA.
FIG. 3 shows SDS-PAGE of 26# FGFR1-Fc fusion protein.
FIG. 4 shows the binding of FGF-2 to a gradient concentration of 26# FGFR1-Fc fusion protein.
FIG. 5 shows the affinity between 26# FGFR1-Fc fusion protein and FGF-2.
FIG. 6 shows the effect of 26# FGFR1-Fc fusion protein on the HUVEC cell division induced by FGF-2.
FIG. 7 shows the anti-tumor efficacy of FGFR-Fc in renal carcinoma model
FIG. 8 shows the anti-tumor efficacy of FGFR-Fc in lung carcinoma model



BRIEF DESCRIPTION OF THE SEQUENCES
SEQ ID NO:1 is an amino acid sequence of human FGRF1.
SEQ ID NO:2 is an amino acid sequence of human VEGFR1.
SEQ ID NO:3 is an amino acid sequence of human VEGFR2.
SEQ ID NO:4 is a nucleotide sequence of human FGFR1.
SEQ ID NO:5 is a nucleotide sequence of human VEGFR1.
SEQ ID NO:6 is a nucleotide sequence of human VEGFR2.
SEQ ID NO:7 is an amino acid seq of human IgG Fc.
SEQ ID NO:8 is a DNA seq of human IgG Fc.
SEQ ID NO:9 is a #19 fusion protein.
SEQ ID NO:10 is a #13 fusion protein.
SEQ ID NO:11 is a #22 fusion protein.
SEQ ID NO:12 is a #23 fusion protein.
SEQ ID NO:13 is a #26 fusion protein.
SEQ ID NO:14 is a #29 fusion protein.
SEQ ID NO:15 is a #8 fusion protein.
SEQ ID NO:16 is a DNA seq of #19 fusion protein.
SEQ ID NO:17 is a DNA seq of #13 fusion protein.
SEQ ID NO:18 is a DNA seq of #22 fusion protein.
SEQ ID NO:19 is a DNA seq of #23 fusion protein.
SEQ ID NO:20 is a DNA seq of #26 fusion protein.
SEQ ID NO:21 is a DNA seq of #29 fusion protein.
SEQ ID NO: 22 is a DNA seq of #8 fusion protein.
SEQ ID NO:23 is a DNA seq of VEGFR1 signal peptide.
SEQ ID NO:24 is a forward primer DNA seq of #19 fusion protein.
SEQ ID NO:25 is a forward primer of DNA seq of #13 fusion protein.
SEQ ID NO:26 is a forward primer DNA seq of #22 fusion protein.
SEQ ID NO:27 is a forward primer DNA seq of #23 fusion protein.
SEQ ID NO:28 is a forward primer DNA seq of #26 fusion protein.
SEQ ID NO:29 is a forward primer DNA seq of #29 fusion protein.
SEQ ID NO:30 is a forward primer DNA seq of #8 fusion protein.
SEQ ID NO:31 is a reverse primer DNA seq of FGFR1.
SEQ ID NO: 32 is a forward primer DNA seq of human IgG Fc.
SEQ ID NO:33 is a reverse primer DNA seq of human IgG Fc.
DETAILED DESCRIPTION
Definitions
Unless otherwise defined, all scientific terms used herein have the same meaning as commonly understood by those skilled in the art. With regard to the definitions and terms in the art, reference may be made to Current Protocols in Molecular Biology (Ausubel) by the skilled one. Standard three- and/or one-letter code used for expressing one of 20 common L-amino acids in the art are adopted as the abbreviation of amino acid residues.
Although the number ranges and approximate parameter values are given in a broad range in the present invention, all numbers in the specific examples are described as precise as possible. However, certain errors can exist in any numerical values, which may result from, for example, the standard deviation during the measurement. Additionally, all ranges disclosed herein encompass any and all possible subranges contained therein. For example, it should be understood that the range “from 1 to 10” as described herein encompasses any and all possible subranges between the minimum 1 and the maximum 10 (including the endpoints). Additionally, it should be understood that any reference referred as “incorporated herein” is incorporated in its entirety.
Additionally, it should be noted that unless otherwise clearly and explicitly stated, the singular form includes the plural referent, as used in the present invention. The term “or” and the term “and/or” are used interchangeably, unless otherwise clearly indicated in the context.
As used herein, the term “Fc”, “Fc region”, “Fc fragment” or “immunoglobulin Fc region” refers to the crystallizable fragment of immunoglobulin, and in the present invention, said Fc region is preferably the human IgG1 Fc region.
The term “Fc fusion protein” refers to the antibody-like molecule that incorporates the binding specificity of a heterologous protein and the effector function of a constant region of an immunoglobulin. In terms of the molecular structure, a Fc fusion protein comprises the amino acid sequence having the required binding specificity and the sequence of a constant region of an immunoglobulin. A Fc fusion protein molecule generally comprises a binding site of a receptor or a ligand. The sequence of immunoglobulin constant region may be derived from any immunoglobulin, for example, IgG-1, IgG-2, IgG-3 or IgG-4 subtype, IgA (including IgA-1 and IgA-2), IgE, IgD or IgM.
The term “soluble” protein as used herein refers to a protein that may be dissolved in an aqueous solution at a biologically relevant temperature, pH level and osmotic pressure. The “soluble fusion protein” as used herein is intended to mean that the fusion protein does not contain a transmembrane region or an intracellular region.
As used herein, the term “isolated” refers to a substance and/or entity that: (1) is isolated from at least some components which is present when initially produced (in natural environment and/or in an experiment device) and related thereto and/or (2) is produced, prepared and/or manufactured artificially. The isolated substance and/or entity may be isolated from at least about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, about 98%, about 99%, substantially 100% or 100% other components related to it initially.
The terms “part,” “fragment,” or “portion” interchangeably refer to a part of polypeptide, nucleic acid or other molecular constructs.
The term “Ig-like domain” as used herein refers to immunoglobulin-like domain, which may be found in a plurality of protein families and involved in many biological functions, including cell-cell recognition, cell surface receptor, immune function and the like.
Fibroblast growth factor (FGF) is a heparin-binding growth factor family that has 22 family members in mammals (FGF 1-14, 16-23). FGF is involved in many important biological functions, such as cell multiplication, differentiation, migration, angiogenesis and tumorigenesis. FGF exerts many biological functions by binding and activating the cell surface FGF receptor (FGFR). (See, for example, Eswarakumar et al. Cytokine Growth Factor Rev. 16: 139-149, 2005).
Fibroblast growth factor receptor (FGFR) is the receptor that binds the family members of fibroblast growth factor. A part of fibroblast growth factor receptor is involved in the disease process. In mammals, there are 4 FGFR genes: fgfR1-fgfR4. The fibroblast growth factor receptor is composed of an extracellular domain, transmembrane domain, and intracellular domain. The members in FGFR family can differ from each other in the term of ligand binding properties and kinase domains. However, the extracellular domains thereof are similar. There are three immunoglobulin-like (Ig-like) domains contained in their extracellular domains: the first Ig-like domain, the second Ig-like domain and the third Ig-like domain, and there is also a sequence contained between the first and the second Ig-like domain. The sequence contained between the first and the second Ig-like domain is referred to herein as the intermediate functional sequence region of the Ig-like domain of FGFR. Said intermediate regulation sequence comprises a region of acidic amino acids, referred as the acidic box (AB).
As used herein, the term “the first Ig-like domain of FGFR” or “the first Ig-like domain” refers to the first Ig-like domain in the protein FGFR from the N-terminus, which has, for example, the amino acid sequence corresponding to position 40 to position 118 of SEQ ID NO: 1. Similarly, the term “the second Ig-like domain of FGFR” or “the second Ig-like domain” refers to the second Ig-like domain in the protein FGFR from the N-terminus, which has, for example, the amino acid sequence corresponding to position 163 to position 247 of SEQ ID NO: 1; the term “the third Ig-like domain of FGFR” or “the third Ig-like domain” refers to the first Ig-like domain in the protein FGFR from the N-terminus, which has, for example, the amino acid sequence corresponding to position 270 to position 359 of SEQ ID NO: 1.
Preferably, the FGFR is FGFR1, and the first Ig-like domain of FGFR is the first Ig-like domain of FGFR1, and the second Ig-like domain of FGFR is the second Ig-like domain of FGFR1, and the third Ig-like domain of FGFR is the third Ig-like domain of FGFR1.
A part of sequence of hFGFR1 is given as follows, in which each Ig-like domain is shown in shaded area sequentially, see GenBank AAH15035.1



















The amino acid sequence of FGFR1 may be found in SEQ ID NO: 1, and its encoding nucleotide sequence may be found in SEQ ID NO: 4.
As used herein, the term “the intermediate functional sequence region of the Ig-like domain of FGFR” or “the intermediate functional sequence of the Ig-like domain of FGFR” or “IFS” refers to the sequence between the first Ig-like domain and the second Ig-like domain in the protein FGFR, and preferably, IFS sequence has the amino acid sequence corresponding to position 118 to position 162 of SEQ ID NO: 1.
Unexpectedly, in accordance with the present invention, it has been found that there is a significant effect of the intermediate functional sequence region on the function of the Ig-like domain. In some embodiments of the present invention, the part derived from the intermediate functional sequence region contains no acidic box. More preferably, the part derived from IFS has the amino acid sequence corresponding to position 134 to position 162, position 145 to position 162, or position 151 to position 162 of SEQ ID NO: 1.
The protein FGFR is preferably FGFR1 (SEQ ID NO: 1), especially the protein FGFR1. The amino acid sequence of the human FGFR1 is shown in SEQ ID NO: 1, and its cDNA sequence is shown in SEQ ID NO: 4.
The term “FGFR” as used herein refers to fibroblast growth factor receptor, which may be FGFR1, FGFR2, FGFR3 and/or FGFR4. Preferably, the FGFR of the present invention is FGFR1, more preferably, human FGFR1.
As used herein, the term “degenerate variant” means that the degenerate variant comprises a degenerate change at the third position of the amino acid codon so that degenerate variants encode the same amino acid, for example the wobble position of a triplet code comprising one or more changed variants (also referred as synonymous variant).
As used herein, the term “subject” refers to mammals, such as humans. It also includes other animals, including domesticated animals (such as dogs and cats), livestock (such as cattle, sheep, pigs and horses) or experimental animals (such as monkeys, rats, mice, rabbits and guinea pigs).
As used herein, the term “percentage identity,” “homology,” or “identity” referred to the sequence identity between two amino acid sequences or nucleic acid sequences. The percentage identity may be determined by alignment between two sequences, and the percentage identity refers to the amount of the same residue (i.e., amino acid or nucleotide) at the same position in the aligned sequences. Sequence alignment and comparison may be performed using standard algorithms in the art (for example Smith and Waterman, 1981, Adv. Appl. Math. 2: 482; Needleman and Wunsch, 1970, J. Mol. Biol. 48: 443; Pearson and Lipman, 1988, Proc. Natl. Acad. Sci., USA, 85: 2444) or by the computerized versions of these algorithms (Wisconsin Genetics Software Package Release 7.0, Genetics Computer Group, 575 Science Drive, Madison, Wis.). Computerized versions that are publicly available include BLAST and FASTA. Additionally, ENTREZ available through National Institutes of Health (Bethesda Md.) may be used for sequence alignment. When BLAST and GAP-BLAST are used, default parameters for each program (for example, BLASTN, available on the website of National Center for Biotechnology Information) may be used. In one embodiment, the percentage identity between two sequences may be determined using GCG with a gap-weight of 1 so that the giving weight of each amino acid gap seems as if it is a single amino acid mismatch between two sequences. Alternatively, ALIGN (version 2.0), which is a part of GCG (Accelrys, San Diego, Calif.) Sequence Alignment Software Package, may be used.
As used herein, the term “hybridization” refers to the process by which a stable double-stranded polynucleotide is formed by non-covalent bonding between two single stranded polynucleotides. The term “hybridization” also may refer to triple-stranded hybridization. The double stranded polynucleotide (generally) produced is the “hybrid” or “duplex”. “The condition for hybridization” generally includes a salt concentration lower than about 1 M, and more generally, lower than about 500 mM, and lower than about 200 mM. The hybridization temperature may be as low as 5° C., but it usually higher than about 22° C., and more usually higher than about 30° C., and preferably higher than about 37° C. Hybridization is usually carried out under strict conditions (i.e., the conditions under which the probe will hybridize to its target sequence). Strict hybridization conditions are dependent on the sequence and will be varied under different conditions. Higher hybridization temperature will be probably required by longer segments for specific hybridization. Since the hybridization stringency may be influenced by other factors (including base composition and length of the complementary strand, the presence of organic solvent and the degree of base mismatch), the combination of parameters is more important than the absolute value of any single parameter. Generally, the strict condition is selected as 5° C. lower than the Tm of the sequence under certain ionic strength and pH. Exemplary strict conditions include pH 7.0 to 8.3, sodium ion (or other salts) concentration of at least 0.01 M to no more than 1 M and temperature of at least 25° C. For strict conditions, see, for 2nd example Sambrook, Fritsche and Maniatis. “Molecular Cloning A laboratory Manual”, edition, Cold Spring Harbor Press (1989) and Anderson “Nucleic Acid Hybridization”, 1st edition, BIOS Scientific Publishers Limited (1999), which are incorporated herein by reference for all purposes mentioned above.
As used herein, the terms “linker,” “peptide linker,” “linking sequence,” and “linker sequence” refer to a short amino acid sequence by which individual domain and/or region involved in the present fusion protein are linked together. The length of the short amino acid sequence is generally 1-20 amino acids, and preferably, 2-10 amino acids.
As used herein, the term of “the amino acid sequence corresponding to SEQ ID NO: N” in a fusion protein or part or domain means that the fusion protein or part or domain has the amino acid sequence substantially as indicated by SEQ ID NO: N, and preferably, containing no more than 1, 2, 3, 4, 5, 10 or 20 substitutions, additions, and/or deletions of amino acids, and preferably, the fusion protein or part or domain shares at least 70%, 80%, 90%, 93%, 95%, 97%, 98% or 99% identity with the amino acid sequence of SEQ ID NO: N, and more preferably, said fusion protein or part or domain has the amino acid sequence as indicated by SEQ ID NO: N.
As used herein, the term “FGFR-Fc fusion protein” refers to a fusion protein that comprises the part derived from the extracellular domain of FGFR and the part derived from the immunoglobulin Fc region, wherein the part derived from the extracellular domain of FGFR may: (1) comprise the amino acid sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity, with the amino acid sequence indicated by any one of SEQ ID NOs: 9-15 or composed thereof; (2) comprise the amino acid sequence encoded by the nucleotide sequence sharing at least 70% identity, preferably at least 80%, 90%, 93%, 95%, 97%, 98% or 99% identity, with the nucleotide sequence indicated by any one of SEQ ID NOs: 16-22 or composed thereof; or (3) possess the amino acid sequence indicated by any one of SEQ ID NOs: 9-15, or the amino acid sequence encoded by the nucleotide sequence indicated by any one of SEQ ID NOs: 16-22.
In some preferable embodiments, the FGFR-Fc fusion protein may be encoded by a nucleic acid, in which the nucleotide sequence encoding the part derived from the extracellular domain of FGFR comprises the sequence of which a complementary sequence is hybridized with the nucleotide sequence as indicated by any one of SEQ ID NOs: 16-22 under stringent conditions, or comprises a degenerative variant of the nucleotide sequence as indicated by any one of SEQ ID NOs: 16-22. In some preferable embodiments, the nucleotide sequence encoding the immunoglobulin Fc region comprises the sequence of which a complementary sequence is hybridized with the nucleotide sequence indicated by SEQ ID NO: 8 under stringent conditions, or comprises a degenerative variant of the nucleotide sequence indicated by SEQ ID NO: 8.
In other preferable embodiments, the FGFR-Fc fusion protein includes the FGFR-Fc fusion protein variant. In one embodiment, the variant includes the variant that contains no more than 2, 3, 4, 5 or 10 substitutions, additions or deletions of amino acid in the part derived from IFS corresponding to the amino acid sequence indicated by position 134 to position 162, position 145 to position 162, or position 151 to position 162 of SEQ ID NO: 1, and preferably, the variant retains the angiogenesis-inhibitory capacity. In another embodiment, the variant contains no more than 2, 3, 4, 5, 10 or 20 substitutions, additions and/or deletions of amino acids in the D2 domain corresponding to the amino acid sequence indicated by position 163 to position 247 of SEQ ID NO: 1, and preferably, the variant retains the angiogenesis-inhibitory capacity. In another embodiment, the variant contains no more than 2, 3, 4, 5, 10 or 20 substitutions, additions and/or deletions of amino acid in D3 domain corresponding to the amino acid sequence indicated by position 270 to position 359 of SEQ ID NO: 1, and preferably, the variant retains the angiogenesis-inhibitory capacity. In another embodiment, the substitution, addition, or deletion is located at the linker or the linking part.
In addition to the naturally occurring modifications in the part derived from the extracellular domain of FGFR and the part derived from immunoglobulin Fc region, other post-translational modifications may also be comprised in the FGFR-Fc fusion protein. Such modifications include, but are not limited to, acetylation, carboxylation, glycosylation, phosphorylation, esterification and acylation. As a result, non-amino acid components may exist in the modified FGFR-Fc fusion protein. These components may be, for example, polyethylene glycol, lipid, polysaccharide or monosaccharide, or phosphoric acid. The effect of such non-amino acid components on the function of the FGFR-Fc fusion protein may be tested as described for other FGFR-Fc fusion protein variants herein. When the FGFR-Fc fusion protein is produced in a cell, post-translational processing is also possibly important for correct folding and/or protein function. Special cell machines and unique mechanisms exist in different cells (for example CHO, HeLa, MDCK, 293, WI38, NIH-3T3 or HEK293) for these post-translational activities, and different cells may be selected by the skilled artisan to improve modification and processing of FGFR-Fc fusion protein.
The fusion protein as described herein may be produced by any method known in the art. For example, it may be produced by chemical synthesis or from nucleic acid expression. The peptides used in the present invention may be easily prepared according to the established standard liquid, or preferably, solid phase peptide synthesis method known in the art (see, for example J. M. Stewart and J. D. Young, Solid Phase Peptide Synthesis, 2′′ edition, Pierce Chemical Company, Rockford, Ill. (1984), in M. Bodanzsky, and A. Bodanzsky, The Practice of Peptide Synthesis, Springer Verlag, New York (1984)). The fusion protein may be produced by the techniques known in the art so that one or more intramolecular crosslinkings may be formed between the cysteine residues located in the polypeptide sequence expected to be comprised in the protein (see, for example U.S. Pat. No. 5,478,925). In addition, general modifications may be performed to the protein described herein by adding, for example, cysteine or biotin to the C-terminus or N-terminus of the protein.
As used herein, “therapeutically effective amount” or “effective amount” refers to a dosage that is sufficient to provide a benefit to the subject to whom it is administrated. The administrated dosage, the rate and the time course of administration are dependent on the condition of the patient and the severity of the disease. Finally, the physician is responsible for the prescription (for example decision on the dosage etc.) and will make a decision for the treatment, usually by considering the disease treated, individual condition of the patient, position of delivery, the method for administration and other factors known to the physician.
A series of isolated soluble FGFR-Fc fusion proteins have been constructed according to the present invention, which may bind FGF and effectively inhibit the cell division induced by FGF. The fusion protein preferably comprises: the part derived from IFS, D2, D3 and immunoglobulin Fc region.
Unexpectedly, it has also been found that the binding of FGF by the fusion protein is significantly influenced by the length of the part derived from IFS. Preferably, the part derived from IFS comprises no acidic box, and more preferably, it has the amino acid sequence corresponding to position 134 to position 162, position 145 to position 162, or position 151 to position 162 of SEQ ID NO: 1. In some preferable embodiments, the part derived from IFS comprises the fusion protein corresponding to the amino acid sequence indicated by position 145 to position 162 of SEQ ID NO: 1, which has extremely high FGF affinity and potential to effectively inhibit cell division induced by FGF.
In some embodiments of the present invention, a soluble FGFR-Fc fusion protein is provided, which comprises: D1, a part derived from IFS, D2, D3 and an immunoglobulin Fc region. Preferably, the part derived from IFS comprises no acidic box, and more preferably, it has the amino acid sequence corresponding to position 134 to position 162, position 145 to position 162, or position 151 to position 162 of SEQ ID NO: 1.
In some other embodiments of the present invention, a soluble FGFR-Fc fusion protein is provided, which comprises: a part of D1, a part derived from IFS, D2, D3 and an immunoglobulin Fc region. Preferably, the part derived from IFS comprises no acidic box, and more preferably, it has the amino acid sequence corresponding to position 134 to position 162, position 145 to position 162, or position 151 to position 162 of SEQ ID NO: 1.
In some other embodiments of the present invention, a soluble FGFR-Fc fusion protein is provided, which comprises: a part derived from IFS, D2, D3 an immunoglobulin Fc region. Preferably, the part derived from IFS comprises no acidic box, and more preferably, it has the amino acid sequence corresponding to position 134 to position 162, position 145 to position 162, or position 151 to position 162 of SEQ ID NO: 1.
In some other embodiments of the present invention, a soluble FGFR-Fc fusion protein is provided, which is sequentially composed of, from the N-terminus to the C-terminus, a part derived from IFS, D2, D3 and an immunoglobulin Fc region. Preferably, the part derived from IFS comprises no acidic box, and more preferably, it has the amino acid sequence corresponding to position 134 to position 162, position 145 to position 162, or position 151 to position 162 of SEQ ID NO: 1.
In some other embodiments of the present invention, an FGFR-Fc fusion protein is provided, which can inhibit tumor cells directly or indirectly. Preferably, the FGFR-Fc fusion protein of the present invention inhibits tumor cells directly. More preferably, the growth of tumor cells is inhibited by the FGFR-Fc fusion protein of the present invention by at least 10%, 20%, 30%, 40%, 50%, 80%, 90% or 95%. The tumor cells may be any tumor cells, for example, leukemia, lung cancer, liver cancer, head and neck cancer, stomach cancer, bladder cancer, or carcinoma of uterine or cervix etc. Preferably, the inhibition is achieved by direct binding to tumor cells.
In some embodiments, the present invention includes use of (i) a FGFR-Fc fusion protein, or (ii) a polynucleotide encoding such fusion protein, in the preparation of the compositions or medicaments for the treatment of diseases mediated by, or related to, angiogenesis. For example, in one embodiment, the present invention provides use of (i) FGFR-Fc fusion protein, or (ii) a polynucleotide encoding such fusion protein in the preparation of a medicament as an angiogenesis inhibitor.
In some embodiments, the FGFR-Fc fusion protein according to the present invention may be produced by the expression of the nucleotide sequence as indicated by any one of SEQ ID NOs: 16-22 in a mammalian cell line. The mammalian cell line can be, for example, a CHO cell line.
Additionally, in the present invention, the FGFR-Fc fusion protein as described below is provided, in which a part derived from the extracellular domain of FGFR may be fused with the immunoglobulin Fc region with or without a linker.
In some other embodiments, the present invention includes the isolated nucleic acid molecules encoding the FGFR-Fc fusion protein, and the present invention also includes use of these molecules in the manufacture of a medicament. The nucleic acid may be recombinant, synthetic or produced by any available methods in the art, and the methods include cloning by means of using standard technique.
In some other embodiments, the present invention includes a vector comprising the nucleic acid molecule of the present invention. The vector may be an expression vector, in which the nucleic acid is operatively linked to a control sequence that is able to facilitate the expression of the nucleic acid in a host cell. A plurality of vectors may be used. For example, suitable vectors may include virus (for example poxvirus, adenovirus, baculovirus etc.); or yeast vectors, bacteriophages, chromosomes, artificial chromosomes, plasmids, and cosmids.
In some embodiments, the present invention further includes the cells transfected by these vectors so that the FGFR-Fc fusion protein is expressed. The host cell suitable for the present invention may be a prokaryotic cell or eukaryotic cell. They include bacteria, for example E. coli; yeast; insect cells; and mammalian cells. The mammalian cell lines that may be used include, but are not limited to, Chinese Hamster Ovary (CHO) cells, baby hamster kidney cells, NS0 mouse myeloma cells, monkey and human cell lines, and derivate cell lines thereof.
In another aspect of the present invention, a method for angiogenesis inhibition is provided, comprising administering the FGFR-Fc fusion protein of the present invention to the subject in need thereof. Preferably, the method is carried out in a mammal.
In another aspect of the present invention, a method for binding FGF in vitro or in vivo is provided, which comprises contacting FGF to the fusion protein according to the present invention.
In another aspect of the present invention, a method for the treatment or prevention of tumors in a mammal is provided, which comprises administering the FGFR-Fc fusion protein of the present invention to the subject in need thereof. Preferably, the tumor is a solid tumor.
In another aspect of the present invention, a method for the treatment or prevention of ophthalmic angiogenesis-related diseases in a mammal is provided, which comprises administering the FGFR-Fc fusion protein of the present invention to the subject in need thereof. Preferably, the ophthalmic angiogenesis-related disease is age-related macular degeneration.
The present invention also relates to use of the FGFR-Fc fusion protein in the preparation of medicaments for angiogenesis inhibition. Additionally, the present invention also relates to use of the FGFR-Fc fusion protein in the preparation of medicaments for the treatment or prevention of angiogenesis-related diseases. Preferably, angiogenesis-related diseases are tumors or ophthalmic angiogenesis-related disease.
Angiogenesis-related diseases include, but are not limited to, angiogenesis-dependent cancers, including, for example, solid tumors, hematogenic tumors (for example leukemia) and tumor metastasis; benign tumors, for example, angioma, acoustic neuroma, neurofibroma, trachoma and pyogenic granuloma; rheumatoid arthritis; psoriasis; rubeosis; Osler-Webber Syndrome; myocardial angiogenesis; plaque neovascularization; telangiectasia; hemophiliac joint and angiofibroma.
In some embodiments of the methods described, one or more FGFR-Fc fusion proteins may be administrated together (simultaneously) or at a different time (sequentially). Additionally, the fusion protein may be administrated together with one or more additional medicaments used for cancer treatment or angiogenesis inhibition.
In some embodiments, the method disclosed in the present invention may be used alone. Alternatively, the subject method may be combined with other conventional anticancer therapies for the treatment or prevention of proliferative diseases (for example tumors). For example, these methods may be used for the prevention of cancers, the prevention of cancer relapse and postoperative metastasis, and may be used as a supplement for other cancer therapies. The effectiveness of conventional cancer therapies (for example, chemotherapy, radiotherapy, phototherapy, immunotherapy and operation) may be enhanced by using target polypeptide therapeutic agents.
In ophthalmology, angiogenesis is related to, for example, diabetic retinopathy, retinopathy of prematurity, age-related macular degeneration, corneal transplantation rejection, neovascular glaucoma and RLF (retrolental fibroplasia). The FGFR-Fc fusion protein disclosed herein can be administrated inside the eye or by other routes. Other diseases related to angiogenesis in ophthalmology include, but are not limited to, epidemic keratoconjunctivitis, Vitamin A deficiency, contact lens overwear, atopic keratitis, superior limbic keratitis, pterygium keratitis sicca, sjogren, acne rosacea, phlyctenosis, syphilis, Mycobacteria infection, lipid degeneration, chemical burn, bacterial ulcer, fungal ulcer, Herpes simplex infection, Herpes zoster infection, protozoan infection, Kaposi sarcoma, Mooren ulcer, Terrien's marginal degeneration, mariginal keratolysis, rheumatoid arthritis, systemic lupus, polyarteritis, trauma, Wegeners sarcoidosis, Scleritis, Steven's Johnson disease, periphigoid radial keratotomy and corneal graph rejection, sickle cell anemia, sarcoid, pseudoxanthoma elasticum, Pagets disease, vein occlusion, artery occlusion, carotid obstructive disease, chronic uveitis/vitritis, mycobacterial infections, Lyme's disease, systemic lupus erythematosis, retinopathy of prematurity, Eales disease, Bechets disease, infection resulting in retinitis or choroiditis, presumed ocular histoplasmosis, Bests disease, myopia, optic pit, Stargarts disease, pars planitis, chronic retinal detachment, hyperviscosity syndromes, toxoplasmosis, trauma and post-laser complication. Other diseases include, but not limited to, rubeosis (neovasculariation of the angle) related diseases and diseases induced by abnormal hyperplasia of the fibrous blood vessel or fibrous tissue, including all kinds of proliferative vitreoretinopathy.
Administration
The fusion protein of the present invention may be administrated alone, but preferably, as a pharmaceutical composition, which usually comprises a suitable pharmaceutical excipient, diluent or carrier selected according to the intended administration route. The fusion protein may be administrated to the patient in need thereof by any suitable route. A precise dosage will be dependent on many factors, including exact properties of the fusion protein.
Some suitable administration routes include (but are not limited to) oral, rectal, nasal, topical (including buccal and sublingual), subcutaneous, vaginal or parenteral (including subcutaneous, intramuscular, intravenous, intracutaneous, intrathecal and extradural) administration.
For intravenous injection and injection at the focal site, active ingredients are present in the form of a parenterally-acceptable aqueous solution, which is free of pyrogen and has appropriate pH value, isotonicity and stability.
A suitable solution may be well formulated by the skilled one in the art using, for example, isotonic excipients such as sodium chloride injection, Ringer's injection, Ringer's lactate injection. As required, preservative, stabilizer, buffering agent, antioxidant and/or some other additives may be added. The pharmaceutical composition orally administrated may be in a form of tablet, capsule, powder or oral liquid etc. Solid carrier, such as gelatin or adjuvant, may be comprised in a tablet. Liquid pharmaceutical composition usually comprises liquid carrier, such as water, petroleum, animal or vegetable oil, mineral oil or synthetic oil. Also included may be normal saline solution, glucose or other sugar solutions or glycols such as ethylene glycol, propylene glycol or polyethylene glycol.
Examples of the techniques and schemes as mentioned above and other techniques and schemes as used according to the present invention may be found in Remington's Pharmaceutical Sciences, 16th edition, Oslo, A. (ed), 1980.
Cloning of the Fusion Protein and Construction of the Expression Plasmid
The FGF receptor fragment can be obtained from the amplification of a cDNA template of a corresponding receptor through PCR. The IgG1 Fc fragment can be obtained from the cDNA amplification of the human-derived IgG1 through PCR. When PCR primers are designed, linking sequences are introduced between different fragments so that these different fragments may be finally linked by overlap PCR to form reading frames for different fusion proteins, and endonuclease BspE I and Pst I sites can be added to both ends of the cDNA. The cDNAs for different fusion proteins may be cloned to the expression plasmid after digestion by BspE I and Pst I. The plasmid after cloning may be determined by endonuclease digestion, electrophoresis and finally DNA sequencing.
Expression and Purification of the Fusion Protein
The present fusion protein may be expressed and purified by techniques commonly used in the art. DNA from corresponding fusion protein plasmid was purified using plasmid purification kit (MAX) available from Qiagen, and the concentration of plasmid DNA can be determined using UV spectrophotometry, and the plasmid was transfected to CHO cell using FUGENE 6 liposome (Roche). Specific methods for transfection can be performed according to the specification of the product.
Based on the expression amount required for the proteins, two methods were employed in the present invention for protein expression: (1) transient expression, in which the fusion protein contained culture supernatant was usually harvested 48-72 h after transfection, and the relative content of the fusion protein was then determined using human IgG ELISA so that the fusion protein may be rapidly and efficiently obtained; (2) establishing a stable cell line and producing the common DHFR-defective CHO cell expression system using the recombinant protein medicament expression, the basic process of which includes cell transfection, selection of stably transfected cell, clone screening, stress amplification, culture medium and process optimization etc., and finally realizing a large-scale suspension culture of CHO engineering cell strain in a serum free culture medium. The culture product was collected and the fusion protein was purified using Protein A affinity column. The purified protein was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and subsequently all eluates in which the required expression product was contained were combined and filtered using a 0.22 μm filter, and then protein quantification was carried out according to a plurality of methods such as Lowry protein assay. The volume of CHO cell culture in the present invention was at a level of 10 L bioreactor, through which the fusion protein obtained after purification could satisfy the protein amount required in the animal experiments, and also a basis was established for future scaling-up.
Neutralization of FGF by the Fusion Protein was Validated at a Level of Protein
After the fusion protein expressed by CHO was obtained, the binding capacity of the fusion protein to FGF is evaluated in the present invention at a level of protein. Binding experiment and affinity experiment were performed for validation in the present invention, in which steps of the binding experiment included: after initially coated by FGF-2 on a 96-well ELISA plate, the coated well was blocked by BSA followed by adding each fusion protein at the same concentration, and then a secondary antibody to human IgG Fc-HRP was added after washing, and the samples were developed, stopped and read at 450 nm on a ELISA plate, and finally the fusion protein which had binding capacity to FGF-2 was screened based on the signal strength. The affinity experiment was performed in order to determine the affinity of the fusion protein to FGF-2 in the solution system, which comprised the following steps: FGF-2 was initially coated on a 96-well ELISA plate to capture the antibody, and then the coated well was blocked by BSA, and subsequently a mixture of the fusion protein and FGF-2 which was previously prepared and incubated were added with a gradient of diluted standards, and after incubation, an HRP-labeled detection antibody was added (using antibody 2 which specifically detected free VEGF or FGF-2), and subsequently the samples were developed, stopped and read at 450 nm on a ELISA plate, and finally the relative concentration of free FGF-2 was detected in the mixture of the fusion protein and FGF-2. Through the experiments above, the fusion protein having a blocking effect on FGF-2 was screened.
Neutralization of FGF by the Fusion Protein was Validated at a Cellular Level
After the binding capacity of the fusion protein to FGF-2 was determined at a level of protein, its angiogenesis-inhibiting effect will be further validated at a cellular level in the present invention. The inhibition capacity of the fusion protein on the division and migration of the vascular endotheliocyte is examined by the division test using human umbilical vein endothelial cell (HUVEC) and the HUEVC cell migration test. The inhibition capacity of the fusion protein on the division of HUVEC cell can be examined by the HUVEC cell division test, which comprises the following steps during the experiment: 3000 HUVEC cells/well were inoculated to a 96-well plate and cultured at 37° C. in an incubator supplemented with 5% CO2, and then FGF-2 as well as a mixture of the fusion protein at different concentrations with FGF-2 are added respectively, and after culturing for another 3-4 days, 10% CCK-8 is added and cultured for 2 h before the sample is read at 450 nm on a ELISA plate. The inhibition capacity of the fusion protein on the division of vascular endotheliocyte induced by FGF-2 was evaluated based on the difference of absorbance, and the median effective concentration of the fusion protein was obtained for FGF-2 inhibition. The inhibition capacity of the fusion protein on HUVEC cell migration was examined by the HUVEC cell migration test, which comprises the following steps during the experiment: 50000 HUVEC cells as well as the fusion protein at various concentrations were initially inoculated in the upper chamber, while 600 μL FGF-2 containing culture liquid was added into the lower chamber, and subsequently, the sample was cultured at 37° C. in an incubator supplemented with 5% CO2 for 20-24 h before cells on the face side of the membrane of the upper chamber were removed, and then cells on the back side of the membrane were fixed, stained and washed with PBS before observed and counted under an inverted microscope. The migration of HUVEC cells induced by the stimulation of FGF-2 was demonstrated by counting the HUVEC cells on the back side of the membrane, and the inhibition capacity of the fusion protein on the migration of the vascular endotheliocyte was tested by adding the fusion protein at various concentrations into the culture liquid. Through the experiments mentioned above, the inhibition capacity of the new fusion protein constructed in the present invention was validated on the division and migration of the vascular endotheliocyte induced by FGF-2, which also provided a basis for future animal experiments.
Tumor Growth-Inhibiting Capacity of the Fusion Protein was Validated by the Tumor Model
After the blocking effect of the new fusion protein in the present invention on FGF-2 signal was demonstrated by experiments at a protein level and a cellular level, its anti-tumor capacity would be tested in animal tumor models in the present invention. In the present invention, the anti-angiogenesis and anti-tumor effect of the fusion protein would be validated by models commonly used in searching medicaments for angiogenesis and tumor, for example, LLC mouse lung cancer, U87 gliocytoma, B 16 melanoma and so on. In animal experiments, in addition to conventional control groups, control medicaments, such as VEGF-Trap, FP-1039, would also be included so as to obtain comparative data for anti-tumor capacity. During experiments, 100 μL tumor cell liquid with appropriate amount was subcutaneously injected into C57 mouse on one side of the back, and the tumor volume was measured with a vernier caliper twice a week. Upon the tumor grew to about 200 mm3, the fusion protein at various concentrations was subcutaneously injected and the mice were sacrificed after 2-3 weeks. Subsequently, the tumor volume was measured with a vernier caliper, and the anti-tumor effect of the fusion protein was validated by the size of the tumor. Furthermore, individual tumor tissue was analyzed using methods such as immunohistochemistry to investigate the regulation mechanism of angiogenesis.
EXAMPLES
Example 1
Construction of Recombinant Expression Plasmid for FGFR1-Fc Fusion Protein
The FGF receptor fragment is obtained from the amplification of the cDNA templet of FGF receptor through PCR, and IgG1 Fc fragment is obtained from the cDNA amplification of the human-derived IgG1 through PCR. A commercially available cDNA (PCR Ready First Strand cDNA, derived from human adult colon cancer tissue, BioChain) was used as the template for FGFR1 fragment. Total RNA was extracted from the blood of healthy human subjects using human blood RNA extraction kit (QIAGEN). According to the manufacturer's instruction of reverse transcription kit (Promega), RT-PCR was performed using M-MLV reverse transcriptase (Promega) so that RNA was reversely transcripted to cDNA which was used as the template for IgG1 Fc fragment. RT-PCR was performed according to the manufacturer's instruction of reverse transcription kit, which has the following steps: Oligo dT, dNTP, total RNA and DEPC H2O were mixed homogeneously and reacted at 70° C. for 10 min before placed on ice for 5 min, and subsequently RNase inhibitor, M-MLV reverse transcriptase and reaction buffer were added. The mixture was reacted at 42° C. for 1 h and subsequently at 70° C. for 15 min, and the cDNA obtained may be used as the template.
Various FGFR1 fragments were individually amplified by PCR using the cDNA from human adult colon cancer tissue as the template (the primers were listed in table 1), and IgG1 Fc fragment was amplified by PCR using human blood cDNA as the template (the primers were listed in table 1 and 2). The reaction conditions for the PCR were as follows: 5 min of pre-denaturalization at 98° C., total 30 cycles of 30 s of denaturalization at 98° C., 45 s of annealing at 56° C. and 2 min of extension at 72° C., and finally another 10 min of extension. When PCR primers were designed, 20 or more complementary base sequences were introduced as the linking sequence between FGFR1 fragment and IgG1 Fc fragment so that the FGFR1 fragment and IgG1 Fc fragment may be subsequently linked by overlap PCR to form reading frames for different fusion proteins, and at the same time, restriction endonuclease BspE I and Pst I site were added at both ends of the PCR product.
Subsequently, overlap PCR was carried out to obtain each FGFR1-Fc fusion protein fragment by amplification. The process of the overlap PCR reaction may be divided into two rounds, in which the fragment required for linking and containing no primer was included in the first round with reaction conditions as follows: 5 min of pre-denaturalization at 98° C., 6 cycles of 30 s of denaturalization at 98° C., 45 s of annealing at 56° C. and 5 min of extension at 72° C., and finally another 10 min of extension at 72° C.; after the first round, the second round of PCR was carried out by adding the primers for both ends with reaction conditions as follows: 5 min of pre-denaturalization at 98° C., 30 cycles of 30 s of denaturalization at 98° C., 45 s of annealing at 56° C. and 2 min of extension at 72° C., and finally another 10 min of extension at 72° C.; through the process above, reading frames for different fusion proteins were spliced, and at the same time, restriction endonuclease BspE I and Pst I site were added at both ends of the cDNA.
After amplification, the fragments amplified by PCR were purified using QIAquick PCR purification kit (QIAGEN). cDNAs of various fusion proteins and the eucaryotic expression plasmid pSV2-dhfr (ATCC) were digested by BspE I and Pst I, respectively. Subsequently, 1% agarose gel electrophoresis was performed on the digested samples under a voltage of 90 V. Target fragments were recovered using QIAquick gel extraction kit (QIAGEN) before ligating at 16° C. for 1 h using a ligase (NEB). The mixture for ligation reaction was transformed to the competent Top10 E. coli under the conditions of 90 s of reaction at 42° C. followed by 3 min of standing on ice. After the sterile LB culture broth (free of antibody) added, the mixture was shaken at 250 rpm in a shaker at 37° C. for 1 h before coating on a LB plate supplemented with ampicillin. The plate was cultured overnight in a thermostated incubator at 37° C., and then single colonies were picked out and transferred to an ampicillin-containing LB culture broth. The inoculated culture broth was shaken at 250 rpm in a shaker at 37° C. overnight before the plasmid was extracted using alkaline lysis. Subsequently, the sample was digested by restriction endonuclease before evaluated by 1% agarose gel electrophoresis under a voltage of 90 V. The recombinant plasmid with correct endonuclease digestion was confirmed by DNA sequencing. Based on the steps above, 19#, 13#, 22#, 23#, 26#, 29# and 8# expression plasmid for FGFR1-Fc fusion protein were constructed. The protein sequence of FGFR1-Fc in each fusion protein and its encoding nucleotide sequence were listed in Table 3. The schematic diagram of the fusion protein structure was shown in FIG. 1.







TABLE 1 







Primers used for amplification of FGFR1 fragment









Fusion




protein
Upstream primer
Downstream primer





19#
19#-FGFR1For (SEQ ID NO: 24)
FGFR1Rev



TAGTTCCGGAAGGCCGTCCCCGACCTTGCCTG
(SEQ ID NO: 31)




GTTTTGTCCTCCAGGTAC




AGGGGCGAGGTC


 


13#
13#-FGFR1For (SEQ ID NO: 25)
FGFR1Rev



TAGTTCCGGAAAAAATCGCACCCGCATCACAG



 


22#
22#-FGFR1For (SEQ ID NO: 26)
FGFR1Rev



TAGTTCCGGAGTAACCAGCAGCCCCTCGGGC



 


23#
23#-FGFR1For (SEQ ID NO: 27)
FGFR1Rev



TAGTTCCGGATCCTCTTCAGAGGAGAAAGAAAC



 


26#
26#-FGFR1For (SEQ ID NO: 28)
FGFR1Rev



TAGTTCCGGAAAACCTAACCCCGTAGCTCCAT



 


29#
29#-FGFR1For (SEQ ID NO: 29)
FGFR1Rev



TAGTTCCGGACCATATTGGACATCCCCAGAAAAG



 


 8#
8#-FGFR1For (SEQ ID NO: 30)
FGFR1Rev



CTAGCTCCGGACCAGAAAAGATGGAAAAGAAATTGC
















TABLE 2 







Primers used for amplification of IgG1


Fc fragment










Upstream primer
Downstream primer





IgG1 Fc
FcFor (SEQ ID NO: 32)
FcRev


fragment
CTGTACCTGGAGGACAAAACT
(SEQ ID NO: 33)



CACACATGC
GATATCTGCAGTCATTT




ACCCGGAGACAGG
















TABLE 3







Protein sequences and nucleotide sequences for 


FGFR1-Fc fusion proteins









Fusion 
Protein
Nucleotide


protein
Sequence
Sequence





19#
SEQ ID NO: 9
SEQ ID NO: 16


13#
SEQ ID NO: 10
SEQ ID NO: 17


22#
SEQ ID NO: 11
SEQ ID NO: 18


23#
SEQ ID NO: 12
SEQ ID NO: 19


26#
SEQ ID NO: 13
SEQ ID NO: 20


29#
SEQ ID NO: 14
SEQ ID NO: 21


 8#
SEQ ID NO: 15
SEQ ID NO: 22









Example 2
Transient Expression and Quantification of the Fusion Proteins
The DNA of individual fusion protein plasmid was purified using MAX Plasmid Purification Kit (Qiagen). The concentration of the plasmid DNA was determined by UV spectrophotometry. 1 μg recombinant plasmid and 6 μL liposome (FuGENE 6 Transfection Reagent, Roche) were homogeneously mixed into 100 μL fresh IMDM culture broth (GIBCO); after standing for 15 min, the mixture was added to the CHO cells (ATCC) cultured overnight after inoculation at a cell density of 3×105/mL into a 6-well plate; the mixture was cultured at 37° C. in an incubator supplemented with 5% CO2 for 48 h with a cell complete culture broth (IMDM medium containing 10% FBS, 1% HT and 1% glutamine, all supplied by GIBCO); subsequently, the supernatant was collected and determined for the relative content of the fusion protein using human IgG ELISA kit for protein quantification (BETHYL). The relative content of the fusion protein expressed and secreted by CHO was determined with the following steps: 100 μL anti-human IgG-Fc protein (10 μg/mL) purified by affinity was coated to a 96-well ELISA plate (IMMULON) and subsequently washed for 5 times using 300 μL PBST washing solution; each coated well was blocked with 200 μL freshly prepared blocking working solution (blocking stock solution:PBS=1:19) and incubated at 37° C. for 1 h; after washed in 300 μL PBST washing solution for 5 times, 100 μL IgG solution diluted in a gradient (200 ng/mL original concentration and diluted by PBS in the multiple proportion of 1:2) as a standard and 100 μL culture supernatant of each fusion protein diluted in a gradient (starting with the concentration of each culture supernatant, and diluted by PBS in the multiple proportion of 1:5) were added to each well and incubated at 37° C. for 2 h; after washed in 300 μL PBST washing solution for 5 times, 100 μL anti-human IgG Fc-HRP secondary antibodies diluted with PBS in a ratio of 1:10000 was added and incubated at 37° C. for 1 h; after washed, the well was developed by adding 100 μL developing solution (KPL); finally, after the development was stopped by adding 100 μL stopping solution (KPL), the absorbance of the ELISA plate was read at a wavelength of 450 nm on a ELISA reader. The concentrations of various fusion proteins may thereby be determined according to the standard curve.
Example 3
Binding of the Fusion Proteins
The binding capacity of 19#, 13#, 22#, 23#, 26#, 29# and 8# fusion protein constructed above to FGF-2 was detected by ELISA.
Initially, a 96-well ELISA plate (IMMULON Company) was coated by 100 μL solution containing 50 ng/mL FGF-2 (R&D Systems) as well as containing 100 ng/mL heparin (Sigma Company) and 50 ng/mL FGF-2. Subsequently, the plate was washed by 300 μL PBST washing solution for 5 times before each coated well was blocked by 200 μL freshly prepared blocking working solution (KPL Company) (blocking stock solution:PBS=1:19) and incubated at 37° C. for 1 h. After washed in 300 μL PBST washing solution for 5 times, 100 μL solutions of various fusion proteins (dissolve in PBS, pH=7.2, concentration of 20 ng/ml) were added and incubated at 37° C. for 2 h. After washed in 300 μL PBST washing solution for 5 times, 100 μL secondary antibody to human IgG Fc-HRP (BETHYL Company) diluted with PBS in a ratio of 1:10000 was added and incubated at 37° C. for 1 h. After washing in 300 μL PBST washing solution 5 times, the well was developed to the presence of color at room temperature in a dark place by adding 100 μL developing solution (KPL Company), and finally the development was stopped by adding 100 μL stopping solution (KPL Company) before the absorbance of the ELISA plate was read at a wavelength of 450 nm on a ELISA reader.
The higher the binding capacity of the fusion protein to FGF2, the larger the absorbance and the stronger the signal. Based on the strength of the signal, 26# fusion protein was determined to have the highest binding capacity to FGF-2.
Comparison of FGF-2 binding among various fusion proteins is shown in FIG. 2. It can be seen from FIG. 2 that 19#, 13#, 22#, 23#, 26# and 29# fusion protein bound to FGF at different extents in the presence of heparin, and particularly, the binding extent of 23#, 26# and 29# was extremely higher than control, and higher than that of 19#, 13# and 22#, indicating that the fusion proteins containing no acidic box had excellent effect.
Among others, especially high binding extent was demonstrated by 26#, indicating that the fusion protein had significantly better binding effect when it comprises a part of certain length derived from the intermediate functional sequence of the Ig-like domain of FGFR.
Example 4
Stable Expression and Purification of the Fusion Proteins
DHFR-defective CHO cells (ATCC) were transfected by the recombinant expression plasmid of 26# fusion protein (possessing a high FGF-2 binding capacity) through a liposome (Roche).
Particularly, 5 μg recombinant plasmid and 30 μL liposome (FuGENE 6 Transfection Reagent, Roche) were homogeneously mixed into 100 μL fresh IMDM culture broth (GIBCO); after standing for 15 min, the mixture was added to the DHFR-defective CHO cells (ATCC) cultured overnight after inoculation at a cell density of 3×105/mL in a 10 cm culture dish (Corning); the mixture was cultured at 37° C. in an incubator supplemented with 5% CO2 for 2-3 days with a cell complete culture broth containing 10% FBS, 1% HT and 1% glutamine in a IMDM culture medium (all supplied by GIBCO); subsequently, the cells were digested by trypsin (GIBCO), inoculated at a cell density of 3×105/mL in 30 mL serum-free 302 culture medium (SAFC) in a flask, and selectively cultured at 37° C. in an incubator supplemented with 5% CO2 at 100 rpm to a cell density of 106/mL.
Subsequently, 3000 cells were inoculated into a 10 cm culture dish (Corning) (the culture broth containing 10% FBS and 1% glutamine in an IMDM culture medium) and cultured at 37° C. in an incubator supplemented with 5% CO2 to form single clones.
These single clones were picked out and cultured in a 96-well plate (Corning). The relative content of the fusion protein expressed and secreted by each individual single clone was determined using a human IgG ELISA kit for protein quantification (BETHYL) under the same conditions and steps as described in Example 2 for the determination of the relative content of the fusion protein. The clone with the highest expression amount was screened out and transferred to a 6-well plate for culturing to a confluence rate of about 70%. The cells were digested by trypsin and transferred to a 10 cm culture dish. Subsequently, gradual stress amplification was carried out by adding methotrexate (MTX, Sigma) with various concentrations (10 nM, 20 nM, 50 nM, 100 nM, 200 nM and 500 nM). After stress amplification, the cells were digested by trypsin and inoculated at a cell density of 3×105/mL in a flask. The expression amount of a single cell was determined so that genetically engineered stains of CHO were obtained for expressing a particular fusion protein. Finally, large-scale suspension culture (volume of 10 L) of the genetically engineered stain of CHO was carried out at 37° C., 5% CO2, 40% dissolved oxygen and 80 rpm in a serum-free 302 culture medium (pH 7.0, SAFC). The culture product was collected by centrifugation. After the supernatant was filtered using 0.45 μm filter membrane (Millipore), affinity chromatography was performed according to the instruction manual of Protein A affinity column (GE) with the specific steps as follows: initially, a protein A affinity column was equilibrated by a PBS buffer (pH 7.0); subsequently, the supernatant was loaded on the column and washed again with the PBS buffer; finally, the column was eluted with a citric acid buffer (pH 3.0), and the eluent was collected and filtered by a 0.45 μm filter membrane. After virus inactivation by adding S/D (0.3% tributyl phosphate/1% Tween 80) at 24° C. for 6 h, the target protein was further purified by a molecular sieve chromatography with the following steps: first, the eluent obtained from the Protein A affinity chromatography was dialyzed in a dialysis bag against a PBS buffer; subsequently, the sample was concentrated in a 10 KD ultrafiltration cup (Millipore); the sample concentrated using the ultrafiltration cup was then loaded on a molecular sieve chromatography column Superdex 200 (GE) equilibrated by a PBS buffer, and subsequently the column was eluted with a PBS buffer and the eluting peak was collected. The purified protein was analyzed by SDS-PAGE (FIG. 3); and subsequently, the eluates containing the required expression product was combined and filtered with a 0.22 μm filter membrane (Millipore) before the protein content was determined using many methods such Lowry protein assay.
Example 5
Gradient-Binding Experiment of the Fusion Proteins
The binding capacities of the fusion proteins as constructed above to FGF-2 were detected by ELISA, similarly as in Example 3.
Initially, a 96-well ELISA plate was coated by 100 μL solution containing 50 ng/mL FGF-2 (R&D Systems). Subsequently, the plate was washed in 300 μL PBST washing solution for 5 times before each coated well was blocked by 200 μL freshly prepared blocking working solution (KPL) (blocking stock solution:PBS=1:19) and incubated at 37° C. for 1 h. After washed in 300 μL PBST washing solution for 5 times, 100 μL solutions containing various fusion proteins at different concentrations (the starting content of protein was 16000 pM, and was diluted in a ratio of 1:3) were added and incubated at 37° C. for 2 h. After washed in 300 PBST washing solution for 5 times, 100 μL anti-human IgG Fc-HRP secondary antibody (BETHYL) diluted with PBS in a ratio of 1:10000 was added and incubated at 37° C. for 1 h. After washed in 300 μL PBST washing solution for 5 times, the well was developed by adding 100 μL developing solution (KPL), and finally the development was stopped by adding 100 μL stopping solution (KPL) before the absorbance of the ELISA plate was read at a wavelength of 450 nm on a ELISA reader. Based on the intensity of the signal, the gradient binding capacities of the fusion proteins to FGF-2 were determined. In the experiment procedure mentioned above, specific conditions and steps may be found in Example 3. Gradient binding of 26# fusion protein to FGF-2 was compared in FIG. 4. It can be seen that the binding capacity of 26# fusion protein to FGF-2 was dose-dependent.
It has been suggested by this example that the binding capacity to FGF-2 increased with an enhanced molar concentration of 26# fusion protein, manifested by a stronger signal at a wavelength of 450 nm; while the binding capacity to FGF-2 decreased correspondingly with a gradient dilution of the molar concentration of 26# fusion protein.
Example 6
Affinity Experiment of the Fusion Proteins
The affinity of the fusion protein to FGF-2 in a solution system was deter mined by an affinity experiment.
Initially, a 96-well ELISA plate was coated by 100 μL solution containing 2.0 μg/mL FGF-2 capture antibody (R&D Systems). Subsequently, the plate was washed in 300 μL PBST washing solution for 5 times before each coated well was blocked by a blocking working solution (KPL) (as seen in Example 3) and incubated at 37° C. for 1 h. After washed in 300 μL PBST washing solution for 5 times, previously prepared and incubated (4° C. overnight) mixture of the fusion proteins and FGF-2 as well as the standard (R&D Systems) diluted in a gradient were added, in which the specific preparation procedure was as follows: the starting concentration of 26# fusion protein was 400 pM (dissolved in PBS) and diluted in a gradient ratio of 2-fold, and the solutions of the fusion protein were 1:1 mixed with 20 pM FGF-2 solution (dissolved in PBS), and that is, the starting final concentration of each fusion protein was 200 pM, and the final concentration of FGF-2 was 10 pM in the mixture solution prepared. The plate was incubated at 37° C. for 2 h and washed in 300 μL PBST washing solution for 5 times before 100 μL FGF-2 detection antibody solution (250 ng/mL) was added (R&D systems, which may specifically detect free antibodies against FGF-2). The plate was incubated at 37° C. for 2 h and washed in 300 μL PBST washing solution for 5 times, and subsequently, HRP labeled streptavidin (R&D systems) was added (diluted by PBS in 1:200). The plate was incubated at 37° C. for 2 h and washed in 300 μL PBST washing solution for 5 times before the well was developed at room temperature in a dark place for an appropriate duration (about 15-30 min) by adding 100 μL developing solution (KPL). Finally, after the development was stopped by adding 100 μL stopping solution (KPL), the absorbance of the ELISA plate was read at a wavelength of 450 nm on a ELISA reader. The relative concentration of free FGF-2 in the mixture of the fusion protein and FGF-2 was determined. The affinity between 26# fusion protein and FGF-2 in a solution system can be seen in FIG. 5. As demonstrated in this Example, 26# fusion protein had high affinity to FGF-2 in a solution system. The affinity increased with an enhanced concentration, which is manifested as a decreased amount of free FGF-2 with an enhanced concentration of the fusion protein. The affinity between 26# fusion protein and FGF-2 in a solution system can be seen in FIG. 5. As demonstrated in this Example, 26# fusion protein had affinity to FGF-2 in a solution system. The affinity increased with an enhanced concentration, which is manifested as a decreased amount of free FGF-2.
Example 7
Inhibitory Test for Division on Human Umbilical Vein Endothelial Cell 
The inhibitory ability of the fusion proteins on the division of vascular endothelial cells was examined in a division test for human umbilical vein endothelial cell (HUVEC).
HUVEC cells (AllCells) were cultured to the exponential growth phase in an HUVEC complete medium (AllCells) at 37° C. in an incubator supplemented with 5% CO2. HUVEC cells were counted after digested by trypsin. 3000 HUVEC cells were inoculated per well in an HUVEC basal medium containing 1% FBS (AllCells) in a 96-well plate. The plate was cultured overnight at 37° C. in an incubator supplemented with 5% CO2.
100 μL FGF-2 (R&D Systems) solution (final concentration of 5 ng/mL) diluted by an HUVEC basal medium containing 1% FBS, as well as 100 μL mixture of various amount of 26# fusion protein and FGF-2 (in which the final concentration of the fusion protein was 40 pM, diluted in an HUVEC basal medium containing 1% FBS with a ratio of 1:10, and the final concentration of FGF-2 was 5 ng/mL) were added and cultured for another 3-4 days. Subsequently, the culture medium was taken out and a culture medium containing 10% CCK-8 (DOJINDO) was added for another 2 h of culture before the absorbance of the 96-well plate was read directly at a wavelength of 450 nm on an ELISA reader. Based on the difference of the absorbance, the inhibitory ability of the fusion protein on the division of vascular endothelial cells induced by FGF-2 was determined. The effect of the fusion protein on HUVEC cell division induced by FGF-2 was shown in FIG. 6. As demonstrated in this Example, 26# fusion protein has biological activity and function at the cellular level, which can inhibit HUVEC cell division induced by FGF-2, and has the binding capacity to FGF-2. Such binding capacity increases as the molar concentration of 26# fusion protein increases, which is indicated by the inhibition of HUVEC cell division induced by FGF-2.
Example 8
Anti-Tumor Efficacy of FGFR-Fc in Renal Carcinoma Model
Human renal carcinoma cell line Caki-1 cells (2×106 cells/mouse) and human lung carcinoma cell line A549 cells (5×106 cells/mouse) were suspended in serum-free medium and s.c. injected into the right flanks of 6 to 8 weeks old female, athymic BALB/c nu/nu mice. Tumor volume was calculated twice a week with a caliper by the formula of [(length×width×width)/2]. When tumor size reached around 50 ̃100 mm3, animals were randomized into four groups and received a s.c. injection of FGFR-Fc (#26 fusion protein) at a dose of 25, 2.5, 0.25 mg/kg and PBS twice weekly for 6 to 8 weeks. 3 days after the last dose, animals were sacrificed and tumors were measured. The results are shown in FIG. 7.
Example 9
Anti-Tumor Efficacy of FGFR-Fc in Lung Carcinoma Model
Effect of FGFR-Fc (#26 fusion protein) on Caki-1 and A549 tumor growth in vivo. Caki-1 cells (2×106; A) and A549 cells (5×106; B) were s.c. injected into BALB/c nu/nu mice. FGFR-Fc blocked the growth of indicated s.c. implanted tumors, at the indicated doses twice weekly for 6 to 8 weeks. The tumor volumes [(length×width×width)/2] were measured, error bars represent standard error of mean, n=6-8 mice/treatment group. The results are shown in FIG. 8.
The present invention has been illustrated by specific examples. However, it will be appreciated by a person of ordinary skill in the art that the present invention is not limited to the specific embodiments. Various changes and modifications may be made by a person of ordinary skill under the scope of the present invention, and each technical feature mentioned in the specification may be combined without departing from the spirit and scope of the invention. Such changes and modifications fall within the scope of the present invention.
All patents, patent applications, provisional applications, and publications referred to or cited herein are incorporated by reference in their entirety, including all figures and tables, to the extent they are not inconsistent with the explicit teachings of this specification.
It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application.
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## Claims

1. An isolated soluble fusion protein comprising SEQ ID NO: 12.

2. An isolated soluble fusion protein comprising SEQ ID NO: 13.

3. An isolated soluble fusion protein comprising SEQ ID NO: 14.

4. The isolated soluble fusion protein, according to claim 1, which consists of SEQ. ID NO:12.

5. The isolated soluble fusion protein, according to claim 2, which consists of SEQ. ID NO:13.

6. The isolated soluble fusion protein, according to claim 3, which consists of SEQ. ID NO:14.