WO2009108633A2

WO2009108633A2 - Sphingosine 1-phosphate antagonism

Info

Publication number: WO2009108633A2
Application number: PCT/US2009/035001
Authority: WO
Inventors: Deron R. Herr; Greg L. Harris
Original assignee: Expression Drug Designs, Llc.
Priority date: 2008-02-25
Filing date: 2009-02-24
Publication date: 2009-09-03
Also published as: EP2262528A2; WO2009108633A3

Abstract

Materials and method for treating cancer and screening for anti-neoplastic agents are provided. These materials and methods can include sphingosine 1 -phosphate antagonists that bind to sphingosine- 1 phosphate receptor subtype 3. Antibodies and aptamers that selectively bind to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine- 1 -phosphate receptor subtype 3 are provided.

Description

SPHINGOSINE 1 -PHOSPHATE ANTAGONISM

[OOOIJ This application claims priority to U.S. Provisional Patent Application No. 61/031,1 1 1, filed February 25, 2008, incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

[0002] Sphingosine 1 -phosphate (SlP) is a small signaling lipid molecule that is present in low concentrations in the plasma membrane of nearly all eukaryotic cells and at high concentrations in serum. SlP is generated by the phosphorylation of sphingosine by sphingosine kinase (SphK) and acts on a family of five known S IP- selective G protein-coupled receptors (the five subtypes designated as Sl Pl , S1P2, S 1 P3, S 1 P4, and Sl P5). These receptors couple to a number of G-proteins and downstream effectors to elicit a variety of cellular responses. The responses vary depending on the expression profile of the receptors and effectors, but notably include proliferation, survival, and cytoskeletal rearrangement.

[0003] SI P and its receptors have been implicated as playing a role in cancer. Not all receptor subtypes appear to play an equal role in cancer and blocking some subtypes could elicit harmful side effects and might even promote cancer. For example, FTY720 is a broad-spectrum S l P receptor inverse agonist that has been reported to effectively inhibit four of the five known receptors (with the exception of S1P2) by stable internalization. Administration of FTY720 has been shown to inhibit angiogenesis and subsequent growth in a tumor transplant model. This effect is mediated through the functional antagonism of S lPl and S1P3. An unfortunate side- effect of S l Pl antagonism is marked lymphopenia and immunosuppression. Accordingly, there is a significant need in the art for Sl P3 selective antagonists that would retain the tumor-suppressive and anti-angiogenic properties of FTY720 without the immunosuppression associated with SlPl antagonism.

[0004] Although there are many chemotherapeutic medications on the market, few, if any, of these medications appear to be sufficient to consistently treat cancer in patients. Accordingly, it is a further object of this invention to identify anti-neoplastic agents that can enhance the efficacy of existing chemotherapeuitcs. SUMMARY OF THE INVENTION

[0005] An isolated sphingosine-1 -phosphate (Sl P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1P3) is provided by the invention. In some embodiments, the amino acid sequence KKTFSLSPTVWFLR.EG comprises the epitope. Examples of antagonist types include antibodies and aptamers. The antagonist can be an anti-neoplastic agent. Compositions comprising the antagonist and one or more (further) anti-neoplastic agents are also provided by the invention. Examples of anti-neoplastic agents include an estrogen receptor binder, antimetabolites, taxanes, anthracyclines, progestins, megestrols, aromatase inhibitors, tyrosine kinase inhibitors, and epidermal growth factor inhibitors.

[0006] A method of treating a cancer cell in a subject is provided by the invention. The method comprising administering an effective amount of a first anti-neoplastic agent comprising an isolated sphingosine-1 -phosphate (S l P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S 1 P3) thereby treating the cancer cell in the subject. The cancer treatment can comprise antagonizing one or more of the following: proliferation of the cell, remodeling of the cell, migration of the cell, invasion by the cell, and survival of the cell. The cancer cell treated can be of any suitable cancer cell type. For example, the cancer cell can comprise one or more of a breast cancer cell, a colorectal cancer cell, a cervical cancer cell, an endometrial cancer cell, an ovarian cancer cell, a prostate cancer cell, a lung cancer cell, a glioblastoma cell. The method can comprise administering a second anti-neoplastic agent, separately or in combination, wherein the first anti-neoplastic agent enhances the second anti-neoplastic agent or vice versa. In some embodiments, the enhancement is synergistic. When administering first and second anti-neoplastic agents, a composition of the invention can be administered.

[0007] A method for identifying a test agent that enhances the efficacy of an antineoplastic agent in antagonizing a neoplastic cell is provided by the invention. The method can comprise the following steps. A first sample comprising a neoplastic cell is provided. A second sample comprising a neoplastic cell is provided. The type(s) of neoplastic cell in the first and second samples can be the same. The anti-neoplastic agent is applied to the first and second samples. The test agent is applied to the second sample. The first and second samples are assayed for an anti-neoplastic effect. The test agent is identified as an enhancer or not an enhancer based on the effect measured in the second sample compared to the effect measured in the first sample. The test agent employed is an isolated sphingosine-1 -phosphate (SlP) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1 P3). In some embodiments, the enhancement is synergistic. Examples of anti-neoplastic results that can be measured include cell stabilization, cell death, growth inhibition, cytoskeletal stabilization, and migration inhibition.

[0008] Use of an isolated sphingosine-1 -phosphate (SlP) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S 1P3) to treat a cancer cell in a subject is provided by the invention. The invention also provides use of an isolated sphingosine-1 -phosphate (Sl P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 - phosphate receptor subtype 3 (S1 P3) for the manufacture of a medicament to treat cancer.

[0009] Kits employing compounds and compositions of the invention and that can be employed in the uses and methods of the invention are provided. A kit comprising at least two elements is provided by the invention. First, the kit includes an isolated sphingosine-1 -phosphate (SlP) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 - phosphate receptor subtype 3 (S1P3). Second, the kit includes an anti-neoplastic agent.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention provides an isolated sphingosine-1 -phosphate (S lP) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1P3). The amino acid sequence KKTFSLSPTV WFLREG can comprise the epitope. The antagonist can take any suitable form. The antagonist binds to sphingosine-1 -phosphate receptor subtype 3 (S1P3) such that the binding of Sl P to the receptor is completely or partially abolished. The antagonist can be a competitive inhibitor, a noncompetitive inhibitor or both of Sl P. The antagonist can be a reversible inhibitor, an irreversible inhibitor or both of SlP. In some embodiments, the Sl P antagonist is an antagonist or partial antagonist of the S 1 P3 receptor. In some embodiments, the Sl P antagonist is an agonist or partial agonist of the S 1 P3 receptor.

[0011] An isolated molecule is one that has been removed from the environment in which it naturally occurs. An isolated molecule can be returned to the environment in which it occurs and still be considered an isolated molecule as it had been previously separated from its natural environment. Isolated molecules include isolated nucleic acids, isolated proteins, isolated polypeptides, and isolated antibodies.

[0012] The S lP antagonist can comprise an antibody or a polypeptide comprising an antigen-binding fragment of the antibody. In some embodiments, the antibody is a chimeric antibody. In some embodiments, the antibody is a humanized antibody. In some embodiments, the antibody is a completely humanized antibody. The antibody can be a monoclonal antibody. The antibody can be a polyclonal antibody.

[0013] The Sl P antagonist can comprise an aptamer. In some embodiments, the aptamer comprises a nucleic acid. The aptamer can comprise RNA. The aptamer can comprise DNA. Aplamers comprising nucleic acids can comprise natural and/or modified (non-natural) nucleotides. The aptamer can comprise an amino acid.

[0014] The S lP antagonist, in addition to being able to bind S 1P3, can have one or more additional attributes. For example, it can bind or be operatively associated with one or more molecules or atoms. These molecules or atoms can comprise a cell toxin and/or render the antagonist detectable by one or more means, [0015] The invention provides compositions that comprise one or more antagonist of the invention. These compositions can further comprise one or more anti-neoplastic agents. This anti-neoplastic agent is in addition to the S 1 P3 inhibitor itself, which can also be a anti-neoplastic agent. An anti-neoplastic agent is an agent that can be used in any suitable manner to treat and/or assist in the treatment of a cancer cell. The compositions can comprise one or more pharmaceutically acceptable excipient. In some embodiments, the anti-neoplastic agent of the composition binds to an estrogen receptor. For example, anti-neoplastic agents that bind an estrogen receptor can include tamoxifen, toremifene, raloxifene, clomiphene, any prodrug thereof, any salt thereof, and any combination thereof. In some embodiments, the anti-neoplastic agent of the composition is an antimetabolite, a prodrug thereof, a salt thereof, or any combination thereof. For example, an antimetabolite can comprise methotrexate, capecitabine, cladribine, cytarabine, fludarabine, fluorouracil, gemcitabine, mercaptopurine, thioguanine, any prodrug thereof, any salt thereof, and any combination thereof. In some embodiments, the anti-neoplastic agent of the composition is a taxane, a prodrug, a salt thereof, or any combination thereof. For example, the taxane, can comprise paclitaxel, docetaxel, any prodrug thereof, any salt thereof, and any combination thereof, In some embodiments, the anti-neoplastic agent of the composition is an anthracycline, a salt thereof, a prodrug thereof, or any combination thereof. For example, the anthracycline can comprise doxorubicin, daunorubicin, idarubicin, epirubicin, any prodrug thereof, any salt thereof, and any combination thereof. In some embodiments, the anti-neoplastic agent of the composition is a progestin, a prodrug thereof, a salt thereof, or any combination thereof. For example, the progestin can comprise megestrol, a prodrug thereof, a salt thereof, or any combination thereof. In some embodiments, the anti-neoplastic agent of the composition is an aromatase inhibitor, a prodrug thereof, a salt thereof, or any combination thereof. For example, the aromatase inhibitor can comprise aminoglutethimide, anastrozole, letrozole, exemestane, any prodrug thereof, any salt thereof, any combination thereof. In some embodiments, the anti-neoplastic agent is a tyrosine kinase inhibitor. Tn some embodiments, the anti-neoplastic agent of the composition binds to an epidermal growth factor receptor. For example, the anti- neoplastic agent can comprise gefitinib, cetuximab, lapatinib, erlotinib, trasluzumab, any prodrug thereof, any salt thereof, and any combination thereof.

[0016] A method of treating a cancer cell in a subject is provided by the invention. The method comprises administering an effective amount of a first anti-neoplastic agent comprising an isolated sphingosine-1 -phosphate (Sl P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1 P3) thereby treating the cancer cell in the subject. The cancer treatment can comprise antagonizing one or more of the following: proliferation of the cell, remodeling of the cell, migration of the cell, invasion by the cell, and survival of the cell. The cancer cell treated can be of any suitable cancer cell type. For example, the cancer cell can comprise one or more of a breast cancer cell, a colorectal cancer cell, a cervical cancer cell, an endometrial cancer cell, an ovarian cancer cell, a prostate cancer cell, a lung cancer cell, a glioblastoma cell. The method of treatment can have anti-angiogenic effects.

[0017] The subject treated in accordance with the invention can have been diagnosed with a cancer or an increased susceptibility for a cancer. Any cancer susceptible to the treatments of the invention can be treated. As used herein, the term "cancer" is meant any malignant growth or tumor caused by abnormal and uncontrolled cell division that may spread to other parts of the body through the lymphatic system or the blood stream. The cancer can be, for example, breast cancer, prostate cancer, lung cancer, colon cancer, rectal cancer, urinary bladder cancer, non-Hodgkin lymphoma, melanoma, renal cancer, pancreatic cancer, cancer of the oral cavity, pharynx cancer, ovarian cancer, thyroid cancer, stomach cancer, brain cancer, multiple myeloma, esophageal cancer, liver cancer, cervical cancer, larynx cancer, cancer of the intrahepatic bile duct, acute myeloid leukemia, soft tissue cancer, small intestine cancer, testicular cancer, chronic lymphocytic leukemia, Hodgkin lymphoma, chronic myeloid cancer, acute lymphocytic cancer, cancer of the anus, anal canal, or anorectum, cancer of the vulva or cancer of the neck, gallbladder, or pleura, malignant mesothelioma, bone cancer, cancer of the joints, hypopharynx cancer, cancer of the eye, cancer of the nose, nasal cavity, neck, or middle ear, nasopharynx cancer, ureter cancer, peritoneum, omentum, or mesentery cancer, or gastrointestinal carcinoid tumor. The cancer can be a tumor. The tumor can be a solid tumor. The cancer can be a hematogeous malignancy. The cancer can be a leukemia. In some embodiments, the leukemia is an acute lymphoblastic leukemia. The cancer can be an ovarian cancer, In some embodiments, the ovarian cancer is an ovarian adenocarcinoma, ovarian carcinoma, clear cell ovarian cancer, endometrioid ovarian cancer, mucinous ovarian cancer, serous ovarian cancer, mixed ovarian cancer, or any combination thereof. The cancer can be a pancreatic cancer. In some embodiments, the pancreatic cancer is a pancreatic adenocarcinoma. The cancer can be a brain cancer. In some embodiments, the cancer is a glioblastoma. The cancer can be a renal cancer. In some embodiments, the renal cancer is a clear cell renal carcinoma. In some embodiments, the cancer is a breast cancer. In some embodiments, the cancer is an estrogen receptor negative breast cancer. In some embodiments, the cancer is a head and neck cancer. In some embodiments, the cancer is a melanoma. The cancer can be in an early, intermediate, or late stage. The cancer can be benign or malignant. In some embodiments, the cancer is metastatic.

[0018] The method can comprise administering a second anti-neoplastic agent, separately or in combination, wherein the first anti-neoplastic agent enhances the second anti-neoplastic agent. Examples of the second anti-neoplastic agent include, but are not limited to those described above for the anti-neoplastic agents of the compositions of the invention. In some embodiments, the enhancement is subadditive. In some embodiments, the enhancement is additive. In some embodiments, the enhancement is synergistic. When administering first and second anti-neoplastic agents, a composition of the invention can be administered. However, the two (or more) anti-neoplastic agents need not be administered in the same composition nor do they need to be given simultaneously.

[0019] The administration of the first and second anti-neoplastic agents can be simultaneous, sequential or in combination. Accordingly, when both first and second anti-neoplastic agents are administered, they need not be administered simultaneously or in the same way or in the same dose. When administered simultaneously, the first and second anti-neoplastic agents can be administered in the same composition or in different compositions. The first and second anti-neoplastic agents can be administered using the same route of administration or different routes of administration. When administered at different times, the first anti-neoplastic agent can be administered before or after the second anti-neoplastic agent. In some embodiments, administration of the first and second anti-neoplastic agents is alternated. In some embodiments, the respective doses of the first and second antineoplastic agents are varied over time. The type of anti-neoplastic agents can be varied over time. When administered at separate times, the separation of the first and second anti-neoplastic agents' administration can be any suitable time period. If administered multiple times, the length of the time period can vary. The separation between administration of the first and second anti-neoplastic agents can be 0 seconds, 1 second, 5 seconds, 10 seconds, 30 seconds, 1 minute, 5 minutes. 10 minutes, 15 minutes, 20 minutes, 30, minutes, 45 minutes, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 4 hours, 5 hours, 7.5 hours, 10 hours, 12 hours, 15 hours, 18 hours, 21 hours, 24 hours, 1.5 days, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 10 days, 2 weeks, 3 weeks, 4 weeks, one month, 6 weeks, 8 weeks, two months, three months, four months, five months, six months, 9 months, 1 year, 2 years, 5, years, 10 years, and any intermediate time period of the preceding.

[0020] In some embodiments, the therapeutic effect on the cancer cell of administering both the first and second anti-neoplastic agents is less than additive. In some embodiments, the effect is substantially additive. However, the first antineoplastic agent preferably potentiates the efficacy of the second anti-neoplastic agent in the therapeutic effect on the cancer cell. In some embodiments, the second antineoplastic agent potentiates the efficacy of the first anti-neoplastic agent in the therapeutic effect on the cancer cell.

[0021 j The first and second anti-neoplastic agents can be administered in synergistic amounts. Accordingly, the administration of both the first and second anti-neoplastic agents can have a synergistic effect on the decrease in cell proliferation whether administered simultaneously, sequentially, or in combination. In some embodiments, the first anti-neoplastic agent increases the efficacy of the second anti-neoplastic agent greater than if the second anti-neoplastic agent were employed alone. In some embodiments, the amount that the second anti-neoplastic agent increases the efficacy of the first anti-neoplastic agent is greater than if the first anti-neoplastic agent were employed alone. The effect of administering both the first and second anti-neoplastic agents can be such that the therapeutic effect on the cancer cell is greater than the additive effect of each being administered alone. When given in synergistic amounts, the first anti-neoplastic agent can enhance the efficacy of the second anti-neoplastic agent even if the amount of first anti-neoplastic agent employed alone, without any second anti-neoplastic agent, would have no substantial therapeutic effect on the cancer cell. For example, even if the first anti-neoplastic agent, e.g., a Sl P3 antagonist, does not by itself result in cell death, it can enhance the ability of a second anti-neoplastic agent, e.g., Tamoxifen, to cause cell death. Measurements and calculations of synergism can be performed as described in Teicher, "Assays for In Vitro and In Vivo Synergy," in Methods in Molecular Medicine, vol. 85: Novel Anticancer Drug Protocols, pp. 297-321 (2003) and/or by calculating the combination index (CI) using CalcuSyn software.

[0022] The method of treating a cancer cell in a subject with a Sl P antagonist provided by the invention can be practiced in addition to radiation treatment and/or surgery, e.g., surgery to remove a tumor or other cancerous growth. In such embodiments, the compounds and compositions of the invention can be administered prior to, concurrent with, and/or subsequent to the radiation and/or surgery. The effect of administration of the SlP antagonist and the radiation and/or surgery can be sub-additive, additive, or synergistic.

[0023] A method for identifying a test agent that enhances the efficacy of an antineoplastic agent in antagonizing a neoplastic cell is provided by the invention. The method can comprise the following steps. A first sample comprising a neoplastic cell is provided. A second sample comprising a neoplastic cell is provided. The type(s) of neoplastic cell in the first and second samples can be the same. The anti-neoplastic agent is applied to the first and second samples. The test agent is applied to the second sample. The first and second samples are assayed for an anti-neoplastic effect. The test agent is identified as an enhancer or not an enhancer based on the effect measured in the second sample compared to the effect measured in the first sample. The test agent employed is an isolated sphingosine-1 -phosphate (Sl P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1P3). In some embodiments, the enhancement is synergistic. Examples of anti-neoplastic results that can be measured include cell stabilization, cell death, growth inhibition, cytoskeletal stabilization, migration inhibition, cell invasion inhibition. Examples of cytoskeletal stabilization comprise a decrease in process retraction, cell surface area reduction, rounding, or any combination thereof. Examples of cell invasion inhibition can include inhibiting the invasion by the cell of tissue or extracellular matrix.

[0024] The anti-neoplastic results can be measured using any suitable technique. For example, Cell death can be determined by use of a terminal uridine deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay as described by Sgonc, R. et al. (1994) Trends in Genetics 10, 41-42. Materials for the TUNEL assay can be obtained in kit format from Roche Applied Science (Basel, Switzerland). Cell death can also be determined by use of an Annexin V assay as described by Kao, S. Y., et al., (2000) Oncogene 19(18):2240-2248. Materials for the Annexin V assay can be obtained in kit format from Invitrogen Corporation (Carlsbad, CA). Cell invasiveness can be assayed by Matrigel invasion assay as described by Melchiori, A., et al., (1992) Cancer Research 52:2353. Materials for the Matrigel invasion assay can be obtained from BD Biosciences (San Jose, CA).

[0025] In some embodiments, the amount of anti-neoplastic agent applied to the first and second samples is the same, and the effect measured in the second sample is greater than the effect measured in the first sample. In some embodiments, the enhancement of the effect is sub-additive. In some embodiments, the enhancement of the effect is additive. In some embodiments, the enhancement of the effect is synergistic. In some embodiments, the amount of anti-neoplastic agent applied to the second sample is less than the amount of the anti-neoplastic agent applied to the first sample, and the effect measured in the first and the second samples is substantially the same. The test agent can be an isolated sphingosine-1 -phosphate (Sl P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (Sl P3). [0026J Any suitable type or types of neoplastic cells can be employed in accordance with the enhancer identification method. For example, the neoplastic cell can comprise a breast cancer cell, a colorectal cancer cell, a cervical cancer cell, an endometrial cancer cell, an ovarian cancer cell, a prostate cancer cell, a lung cancer cell, a glioblastoma cell, and any combination thereof.

[0027] Any suitable anti-neoplastic agent can be employed in accordance with the enhancer identification method. Examples of the second anti-neoplastic agent include, but are not limited to those described above for the anti-neoplastic agents of the compositions of the invention.

[0028] Uses consistent with the compounds, compositions and methods of the invention are provided. Use of an isolated sphiiigosine-1 -phosphate (SI P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1 P3) to treat a cancer cell in a subject is provided by the invention. The invention also provides use of an isolated sphingosine-1 -phosphate (S l P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1 P3) for the manufacture of a medicament to treat cancer.

[0029] Kits employing compounds and compositions of the invention and that can be employed by the uses and methods of the invention are provided. For example, a kit comprising at least two elements is provided by the invention. First, the kit includes an isolated sphingosine- 1 -phosphate (S l P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1P3). Second, the kit includes an antineoplastic agent. Examples of the second anti-neoplastic agent include, but are not limited to those described above for the anti-neoplastic agents of the compositions of the invention. For example, the anti-neoplastic agent can be selected from the group consisting of an estrogen receptor binder, an antimetabolite, a taxane, an anthracycline, progestin, a megestrol, an aromatase inhibitor, an epidermal growth factor inhibitor, any prodrug thereof, any salt thereof, and any combination thereof. [0030] A therapeutic agent, which can be a compound and/or a composition, relevant to the invention can comprise a small molecule, a nucleic acid, a protein, an antibody, an aptamer, or any other agent with one or more therapeutic property. For example, the therapeutic agent can be an anti-neoplastic agent.

[0031] A nucleic acid or nucleotide sequence includes one or more nucleotides. Exemplary nucleic acids include RNA, DNA, any combination thereof. Nucleic acids can include both naturally occurring as well non-naturally occurring nucleotides, ribonucleic acid nucleotides as well as deoxyribonucleic acid nucleotides. When a nucleic acid is recited it refers generically to DNA and RNA unless the recitation explicitly states that the nucleic acid is a specific one, e.g., DNA or RNA. If a nucleic acid refers to a sequence that contains thymine (t), that does not necessarily indicate that the nucleic acid is DNA; in some embodiments the nucleic acid is RNA and/or DNA. Similarly, if a nucleic acid refers to a sequence that contains uracil (u) that does not necessarily indicate that the nucleic acid is RNA; in some embodiments the nucleic acid is DNA and/or RNA.

[0032] The nucleic acid molecules relevant to the invention can readily be obtained in a variety of ways, including, without limitation, chemical synthesis, cDNA or genomic library screening, expression library screening, and/or PCR amplification of cDNA. These methods and others useful for isolating such DNA are set forth, for example, by Sambrook et al., "Molecular Cloning: A Laboratory Manual," Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N. Y. (1989), by Ausubel. et al., eds., "Current Protocols In Molecular Biology," Current Protocols Press (1994), and by Berger and Kimmel, "Methods In Enzymology: Guide To Molecular Cloning Techniques," vol. 152, Academic Press, Inc., San Diego, Calif. (1987).

[0033] Chemical synthesis of a nucleic acid molecule can be accomplished using methods well known in the art, such as those set forth by Engels et al., Angew. Chem. Intl. Ed., 28:716-734 (1989). These methods include, inter alia, the phosphotriester, phosphoramidite and H-phosphonate methods of nucleic acid synthesis. Nucleic acids larger than about 100 nucleotides in length can be synthesized as several fragments, each fragment being up to about 100 nucleotides in length. The fragments can then be ligated together to form a full length nucleic acid encoding the polypeptide. One method is polymer-supported synthesis using standard phosphoramidite chemistry.

[0034] Alternatively, the nucleic acid can be obtained by screening an appropriate cDNA library prepared from one or more tissue source(s) that express the polypeptide, or a genomic library from any subspecies. The source of the genomic library may be any tissue or tissues from a mammalian or other species believed to harbor a gene encoding a protein relevant to the invention. The library can be screened for the presence of a cDNA/gene using one or more nucleic acid probes (oligonucleotides, cDNA or genomic DNA fragments that possess an acceptable level of homology to the gene or gene homologue cDNA or gene to be cloned) that will hybridize selectively with the gene or gene homologue cDNA(s) or gene(s) that is(are) present in the library. The probes preferably are complementary to or encode a small region of the DNA sequence from the same or a similar species as the species from which the library was prepared. Alternatively, the probes can be degenerate. After hybridization, the blot containing the library is washed at a suitable stringency, depending on several factors such as probe size, expected homology of probe to clone, type of library being screened, number of clones being screened, and the like. Stringent washing solutions can be low in ionic strength and are used at relatively high temperatures.

[0035] Another suitable method for obtaining a nucleic acid in accordance with the invention is the polymerase chain reaction (PCR). In this method, poly(A)+RNA or total RNA is extracted from a tissue that expresses the gene product. cDNA is then prepared from the RNA using the enzyme reverse transcriptase. Two primers typically complementary to two separate regions of the cDNA (oligonucleotides) are then added to the cDNA along with a polymerase such as Taq polymerase, and the polymerase amplifies the cDNA region between the two primers.

[0036] The invention provides for the use of isolated, purified or enriched nucleic acid sequences of 15 to 500 nucleotides in length, 15 to 100 nucleotides in length, 15 to 50 nucleotides in length, and 15 to 30 nucleotides in length, which have sequence that corresponds to a portion of one of the nucleotides described herein. The nucleic acid can be at least 17, 20, 22, or 25 nucleotides in length. The nucleic acid sequence can be 30 to 300 nucleotides in length, or 45 to 200 nucleotides in length, or 45 to 100 nucleotides in length.

[0037] The nucleic acid can be at least 5, 6, 7, 8, 9, 10, 12, 15, 17, 20, 22, 25, 30, 35, 40, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 1000, 10,000, 50,000, 100,000 or more nucleotides in length, or 100,000, 75,0005 50,000, 10,000, 5,000, 1000, 750, 500, 250, 200, 100, 50, 40, 30, 25, 22, 20, 17, 15, 12, 10, 9, 8, 7, 6, 5, or fewer nucleotides in length. The nucleic acid can have a length in a range from any one of the above lengths to any other of the above lengths including endpoints.

[0038J A nucleic acid in accordance with the invention can be 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 82%, 84%, 86%, 88%, 90%, 91 %, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, and 100% identical to reference sequences provided herein. A nucleotide that hybridizes under stringent conditions to a nucleotide described herein can be employed. Unless otherwise specified, percent identities for nucleic acids and amino acid sequences are determined as follows. Percent identity of two nucleic acid sequence or two amino acid sequences is determined using the algorithm of Karlin and Altschul (Proc. Natl. Acad. Sci. USA, 87:2264-2268 (2002), modified as in Karlin and Altschul et al., Proc. Nat. Acad. Sci. USA, 90:5873-5877 ( 1993). Such an algorithm is incorporated into the NBLAST and XBLAST programs of Altschul et al., J. MoI. Biol. 215:403-410 (1990). BLAST nucleotide searches are performed with the NBLAST program, score = 100, wordlength = 1, to obtain nucleotide sequences with a percent identity to a nucleic acid employed in the invention. BLAST protein searches are performed with the XBLAST program, score = 50, wordlength = 3, to obtain amino acid sequences with a percent identity to a reference polypeptide. To obtain gapped alignments for comparison purposes, Gapped BLAST is utilized as described in Altschul et al., Nucleic Acids Res., 25:3389-3402 (1997). When utilizing BLAST and Gapped BLAST programs, the default parameters of the respective programs (e.g., XBLAST and NBLAST) are used. See <www.ncbi.nih.gov>. [0039] Unless otherwise specified, a nucleic acid and nucleic acid probe can include one or more nucleic acid analogs, labels or other substituents or moieties so long as the base-pairing function is retained. The nucleic acid probe can comprise a detectable label, such as a radioactive or fluorescent label. A variety of other detectable labels are known to those skilled in the art. Unless otherwise specified, where the sequence for a given strand is provided, the invention also includes its complement in addition or in the alternative.

[0040] In connection with nucleic acid hybridization, the term "specifically hybridizes" indicates that the probe hybridizes to a sufficiently greater degree to the target sequence than to a non-target sequence, e.g., at a level which allows ready identification of probe/target sequence hybridization under selective hybridization conditions. "Selective hybridization conditions" refer to conditions that allow such differential binding. Similarly, the terms "specifically binds" and "selective binding conditions" refer to such differential binding of any type of probe, and to the conditions that allow such differential binding.

[0041] Variables can be adjusted to optimize the specificity of a nucleic acid probe, including changes in salt concentration, temperature, pH and addition of various compounds that affect the differential affinity of GC vs. AT base pairs, such as tetramethyl ammonium chloride. [See Current Protocols in Molecular Biology, Ausubel et al. (Editors), John Wiley & Sons.] Hybridization conditions should be sufficiently stringent such that there is a significant difference in hybridization intensity between alleles, and preferably an essentially binary response, whereby a probe hybridizes to only one of the alleles. Hybridizations can be performed under stringent conditions that allow for specific binding between an oligonucleotide and a target nucleic acid. Stringent conditions are defined as any suitable buffer concentrations and temperatures that allow specific hybridization of the oligonucleotide and any washing conditions that remove non-specific binding of the oligonucleotide. For example, conditions of 5xSSPE (750 niM NaCl, 50 mM Na Phosphate, 5 mM EDTA, pH 7.4) and a temperature of 25-30⁰C are suitable for allele- specific probe hybridizations. The washing conditions can range from room temperature to 6O⁰C. [0042] Polypeptides or fragments thereof can be expressed in an expression vector in which a gene or coding segment thereof or related construct thereof is operably linked to a native or other promoter. The promoter can be a eukaryotic promoter for expression in a mammalian cell. The transcription regulation sequences typically include a heterologous promoter and optionally an enhancer that is recognized by the host. The selection of an appropriate promoter, for example trp, lac, phage promoters, glycolytic enzyme promoters and tRNA promoters, depends on the host selected. Commercially available expression vectors can be used. Vectors can include host- recognized replication systems, amplifiable genes, selectable markers, host sequences useful for insertion into the host genome, and the like.

[0043] The expression construct can be introduced into a host cell in a number of ways depending upon the particular construction and the target host, for example, fusion, conjugation, transfection, transduction, electroporation, or injection, as described in Sambrook, supra. A wide variety of host cells can be employed for expression of the gene or coding segment thereof or related construct thereof including both prokaryotic and eukaryotic. Suitable host cells include bacteria such as E. coli, yeast, filamentous fungi, insect cells, mammalian cells, typically immortalized, e.g., mouse, CHO, human and monkey cell lines and derivatives thereof. Host cells can be selected to process the translated product to produce an appropriate mature polypeptide. Processing includes glycosylation, ubiquitination, disulfide bond formation, and general post-translational modification.

[0044] The protein can be isolated by conventional means of protein biochemistry and purification to obtain a substantially pure product, i.e., 80, 95 or 99% free of cell component contaminants, as described in Jacoby, Methods in Enzymology Volume 104, Academic Press, New York (1984); Scopes, Protein Purification, Principles and Practice, 2nd Edition, Springer- Verlag, New York (1987); and Deutscher (ed), Guide to Protein Purification, Methods in Enzymology, Vol. 182 (1990). If the protein is secreted, it can be isolated from the supernatant in which the host cell is grown. If not secreted, the protein can be isolated from a lysate of the host cells. [0045] In addition to substantially full-length polypeptides expressed by genes or coding segments thereof, the invention includes use of biologically active fragments of the polypeptides, or analogs thereof, including organic molecules that simulate the interactions of the peptides. Biologically active fragments include any portion of the full-length polypeptide that confers a biological function on the expressed product, including ligand binding and antibody binding. Ligand binding includes binding by nucleic acids, proteins or polypeptides, small biologically active molecules or large cellular structures. In some embodiments, the polypeptide is at least 5, 6, 7. 8, 9, 10, 12, 15, 17, 20, 22, 25, 30, 35, 40, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 1000, 10,000, 50,000, 100,000 or more amino acids in length, or 100,000, 75,000, 50,000, 10,000, 5,000, 1000, 750, 500, 250, 200, 100, 50, 40, 30, 25, 22, 20, 17, 15, 12. 10, 9, 8, 7, 6, 5, or fewer amino acids in length. A polypeptide can have a length in a range from any one of the above lengths to any other of the above lengths including endpoints. A polypeptide in accordance with the invention can be 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 82%, 84%, 86%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, and 100% identical to reference sequence provided herein.

[0046] Antibodies specific for an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S 1 P3) and polypeptides comprising antigen binding fragments thereof are provided as well as methods, uses, compositions, and kits employing the same. A method of forming an antibody specific to a human epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1 P3) or a polypeptide a fragment thereof is provided. Such a method can comprise providing a nucleic acid encoding a S1 P3 polypeptide or a polypeptide comprising an immunologically specific epitope thereof; expressing a S 1P3 polypeptide comprising a S1P3 amino acid sequence or a polypeptide comprising an immunologically specific epitope thereof from the isolated nucleic acid; and generating an antibody specific to the polypeptide obtained in step or a polypeptide comprising an antigen binding fragment thereof. An antibody or polypeptide comprising an antigen binding fragment thereof produced by the aforementioned method is provided. An isolated antibody or isolated polypeptide comprising an antigen binding fragment thereof that specifically binds a human epitope in the extracellular loop between transmembrane domains two and three of S1P3 comprising a S1P3 amino acid sequence is provided. Such an antibody can be generated using any acceptable method(s) known in the art. The antibodies as well as kits, methods, and other aspect of the invention employing antibodies can comprise one or more of the following a polyclonal antibody, a monoclonal antibody, and a humanized antibody.

[0047] Antibodies can be used as probes, therapeutic treatments and other uses. Polyclonal and/or monoclonal antibodies and antibody fragments capable of binding to a portion of the gene product relevant for identifying a given target are provided. Antibodies can be made by injecting mice, rabbits, goats, or other animals with the translated product or synthetic peptide fragments thereof. Monoclonal antibodies are screened as are described, for example, in Harlow & Lane, Antibodies, A Laboratory Manual, Cold Spring Harbor Press, New York (1988); Goding, Monoclonal antibodies, Principles and Practice (2d ed.) Academic Press, New York (1986). Monoclonal antibodies are tested for specific immunoreactivity with a translated product and lack of immunoreactivity to the corresponding prototypical gene product. These antibodies are useful in diagnostic assays or as an active ingredient in a pharmaceutical composition.

[0048] Polyclonal or monoclonal therapeutic antibodies useful in practicing this invention can be prepared in laboratory animals or by recombinant DNA techniques using the following methods. Polyclonal antibodies are raised in animals by multiple subcutaneous (sc) or intraperitoneal (ip) injections of the gene product molecule or fragment thereof in combination with an adjuvant such as Freund's adjuvant (complete or incomplete). To enhance immunogenicity, it may be useful to first conjugate the gene product molecule or a fragment containing the target amino acid sequence to a protein that is immunogenic in the species to be immunized, e.g., keyhole limpet hemocyanin, serum albumin, bovine thyroglobulin, or soybean trypsin inhibitor using a bifunctional or derivatizing agent, for example, maleimidobenzoyl sulfosuccinimide ester (conjugation through cysteine residues), N- hydroxysuccinimide (through lysine residues), glutaraldehyde, succinic anhydride, SOCl, etc. Alternatively, immunogenic conjugates can be produced recombinantly as fusion proteins.

[0049] Animals can be immunized against the immunogenic conjugates or derivatives (such as a fragment containing the target amino acid sequence) by combining about 1 mg or about 1 microgram of conjugate (for rabbits or mice, respectively) with about 3 volumes of Freund's complete adjuvant and injecting the solution intradermally at multiple sites. Approximately 7 to 14 days later, animals are bled and the serum is assayed for antibody titer. Animals are boosted with antigen repeatedly until the titer plateaus. The animal can be boosted with the same molecule or fragment thereof as was used for the initial immunization, but conjugated to a different protein and/or through a different cross-linking agent. In addition, aggregating agents such as alum are used in the injections to enhance the immune response.

[0050] Monoclonal antibodies can be prepared by recovering spleen cells from immunized animals and immortalizing the cells in conventional fashion, e.g., by fusion with myeloma cells. The clones are then screened for those expressing the desired antibody. The monoclonal antibody preferably does not cross-react with other gene products. Non- human antibodies can be humanized using any applicable method known in the art. A humanized antibody can be produced using a transgenic animal whose immune system has been partly or fully humanized. Chimeric antibodies can be produced using any known technique in the art. See, e.g., U.S. Patents 5,169,939; 5,750,078; 6,020, 153; 6,420, 1 13; 6,423,51 1 ; 6,632,927; and 6,800,738.

[0051] Preparation of antibodies using recombinant DNA methods such as the phagemid display method, can be accomplished using commercially available kits, as for example, the Recombinant Phagemid Antibody System available from Pharmacia (Uppsala, Sweden), or the SurfZAP™ phage display system (Stratagene Inc., La Jolla, Calif.). Bispecific antibodies that specifically bind to one protein and that specifically bind to other antigens relevant to pathology and/or treatment are produced, isolated, and tested using standard procedures that have been described in the literature. [See, e.g., Pluckthun & Pack, Immunotechnology, 3:83-105 (1997); Carter, et al., J. Hematotherapy, 4:463-470 (1995); Rentier & Pfreundschuh, Immunological Reviews, 1995, No. 145, pp. 179-209; Pfreundschuh U.S. Pat No. 5,643,759; Segal, et al., J. Hematotherapy, 4:377-382 (1995); Segal, et al., ϊmmunobiology, 185:390-402 (1992); and Bolhuis, et al., Cancer Immunol. Immunother., 34: 1-8 (1991)].

[0052] Aptamers can be selected and produced using any suitable technique or protocol. For example, oligonucleotide libraries with variable regions ranging from 18 to 50 nucleotides in length can be used as templates for run-off transcription reactions to generate random pools of RNA aptamers. The resulting pools are extremely diverse containing a theoretical maximum of 1 .27x10³⁰ unique species with the largest library. This aptamer pool is then exposed to unconjugated matrix to remove non-specific interacting species. The remaining pool is then incubated with an immobilized target. The majority of aptamer species in this pool having low affinity for the target will be washed away leaving a smaller, more specific pool bound to the matrix. This pool is then eluted, precipitated, reverse transcribed, and used as a template for run-off transcription. After five rounds of selection, aliquots are removed that are cloned and sequenced. Selection continues until similar sequences are reproducibly recovered.

[0053] Aptamer production can be performed using a bead-based selection system. In this process, a library of beads is generated in which each bead is coated with a population of aptamers with identical sequences composed of natural and modified nucleotides. This bead library, containing >100,000,000 unique sequences, is incubated with a peptide that corresponds to the extracellular loop between transmembrane domains 2 and 3 of S1P3 that is conjugated with a tag such as a fluorescent dye. In some embodiments, the peptide employed comprises the amino acid sequence KKTFSLSPTVWFLREG. After washing, beads that demonstrate the highest binding affinity are isolated and aptamer sequences are determined for subsequent synthesis.

[0054] A therapeutic agent in accordance with the invention can be formulated in any pharmaceutically acceptable manner. In some embodiments, the therapeutic agent is prepared in a depot form to allow for release into the body to which it is administered is controlled with respect to time and location within the body (see, for example, U.S. Patent No. 4,450, 150). Depot forms of therapeutic agents can be, for example, an implantable composition comprising the therapeutic agent and a porous or non-porous material, such as a polymer, wherein the therapeutic agent is encapsulated by or diffused throughout the material and/or degradation of the non-porous material. The depot is then implanted into the desired location within the body and the therapeutic agent is released from the implant at a predetermined rate.

[0055] The therapeutic agent that is used in the invention can be formed as a composition, such as a pharmaceutical composition comprising a carrier and a therapeutic compound. Pharmaceutical compositions containing the therapeutic agent can comprise more than one therapeutic agent. The pharmaceutical composition can alternatively comprise a therapeutic agent in combination with other pharmaceutically active agents or drugs, such as chemotherapeutic agents, for example, a cancer drug.

[0056] The carrier can be any suitable carrier. Preferably, the carrier is a pharmaceutically acceptable carrier. With respect to pharmaceutical compositions, the carrier can be any of those conventionally used and is limited only by chemico physical considerations, such as solubility and lack of reactivity with the active compound(s), and by the route of administration. In addition to the following described pharmaceutical composition, the therapeutic compounds of the present inventive methods can be formulated as inclusion complexes, such as cyclodextrin inclusion complexes, or liposomes.

[0057] The pharmaceutically acceptable carriers described herein, for example, vehicles, adjuvants, excipients, and diluents; are well-known to those skilled in the art and are readily available to the public. The pharmaceutically acceptable carrier can be chemically inert to the active agent(s) and one which has no detrimental side effects or toxicity under the conditions of use. The choice of carrier can be determined in part by the particular therapeutic agent, as well as by the particular method used to administer the therapeutic compound. There are a variety of suitable formulations of the pharmaceutical composition of the invention. The following formulations for oral, aerosol, parenteral, subcutaneous, transdermal, transmucosal, intestinal, intramedullary injections, direct intraventricular, intravenous, intranasal, intraocular, intramuscular, intraarterial, intrathecal, intraperitoneal, rectal, and vaginal administration are exemplary and are in no way limiting. More than one route can be used to administer the therapeutic agent, and in some instances, a particular route can provide a more immediate and more effective response than another route. Depending on the specific disorder being treated, such agents can be formulated and administered systemically or locally. Techniques for formulation and administration may be found in Remington's Pharmaceutical Sciences, 18th ed., Mack Publishing Co., Easton, Pa. (1990).

[0058] Formulations suitable for oral administration can include (a) liquid solutions, such as an effective amount of the inhibitor dissolved in diluents, such as water, saline, or orange juice; (b) capsules, sachets, tablets, lozenges, and troches, each containing a predetermined amount of the active ingredient, as solids or granules; (c) powders; (d) suspensions in an appropriate liquid; and (e) suitable emulsions. Liquid formulations may include diluents, such as water and alcohols, for example, ethanol, benzyl alcohol, and the polyethylene alcohols, either with or without the addition of a pharmaceutically acceptable surfactant. Capsule forms can be of the ordinary hard or soft shelled gelatin type containing, for example, surfactants, lubricants, and inert fillers, such as lactose, sucrose, calcium phosphate, and corn starch. Tablet forms can include one or more of lactose, sucrose, mannitol, corn starch, potato starch, alginic acid, microcrystalline cellulose, acacia, gelatin, guar gum, colloidal silicon dioxide, croscarmellose sodium, talc, magnesium stearate, calcium stearate, zinc stearate, stearic acid, and other excipients, colorants, diluents, buffering agents, disintegrating agents, moistening agents, preservatives, flavoring agents, and other pharmacologically compatible excipients. Lozenge forms can comprise the inhibitor in a flavor, usually sucrose and acacia or tragacanth, as well as pastilles comprising the inhibitor in an inert base, such as gelatin and glycerin, or sucrose and acacia, emulsions, gels, and the like containing, in addition to, such excipients as are known in the art.

[0059] Pharmaceutical preparations that can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer, such as glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with filler such as lactose, binders such as starches, and/or lubricants such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds may be dissolved or suspended in suitable liquids, such as fatty oils, liquid paraffin, or liquid polyethylene glycols. In addition, stabilizers may be added.

[0060] The therapeutic agent, alone or in combination with other suitable components, can be made into aerosol formulations to be administered via inhalation. These aerosol formulations can be placed into pressurized acceptable propellants, such as dϊchlorodifluoromethane, propane, nitrogen, and the like. They also can be formulated as pharmaceuticals for non pressured preparations, such as in a nebulizer or an atomizer. Such spray formulations also may be used to spray mucosa. Topical formulations are well known to those of skill in the art. Such formulations are particularly suitable in the context of the invention for application to the skin.

[0061 ] Injectable formulations are in accordance with the invention. The parameters for effective pharmaceutical carriers for injectable compositions are well-known to those of ordinary skill in the art [see, e.g., Pharmaceutics and Pharmacy Practice, J. B. Lippincott Company, Philadelphia, PA, Banker and Chalmers, eds., pages 238250 (1982), and ASHP Handbook on Injectable Drugs, Toissel, 4th ed., pages 622 630 (1986)]. For injection, the agents of the invention can be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks's solution, Ringer's solution, or physiological saline buffer. For such transmucosal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art.

[0062] Formulations suitable for parenteral administration include aqueous and non aqueous, isotonic sterile injection solutions, which can contain anti oxidants, buffers, bacteriostats, and solutes that render the formulation isotonic with the blood of the intended recipient, and aqueous and non aqueous sterile suspensions that can include suspending agents, solubilizers, thickening agents, stabilizers, and preservatives. The therapeutic agent can be administered in a physiologically acceptable diluent in a pharmaceutical carrier, such as a sterile liquid or mixture of liquids, including water, saline, aqueous dextrose and related sugar solutions, an alcohol, such as ethanol or hexadecyl alcohol, a glycol, such as propylene glycol or polyethylene glycol, poly(ethyleneglycol) 400, glycerol, dimethylsulfoxide, ketals such as 2,2-dimethyl- l,3-dioxolane-4-methanol, ethers, oils, fatty acids, fatty acid esters or glycerides, or acetylated fatty acid glycerides with or without the addition of a pharmaceutically acceptable surfactant, such as a soap or a detergent, suspending agent, such as pectin, carbomers, methylcellulose, hydroxypropylmethylcellulose, or carboxymethylcellulose, or emulsifying agents and other pharmaceutical adjuvants.

[0063] Oils, which can be used in parenteral formulations include petroleum, animal, vegetable, or synthetic oils. Specific examples of oils include peanut, soybean, sesame, cottonseed, corn, olive, petrolatum, and mineral. Suitable fatty acids for use in parenteral formulations include oleic acid, stearic acid, and isostearic acid. Ethyl oleate and isopropyl myri state are examples of suitable fatty acid esters.

[0064] Suitable soaps for use in parenteral formulations include fatty alkali metal, ammonium, and triethanolamine salts, and suitable detergents include (a) cationic detergents such as, for example, dimethyl dialkyl ammonium halides, and alkyl pyridinium halides, (b) anionic detergents such as, for example, alkyl, aryl, and olefin sulfonates, alkyl, olefin, ether, and monoglyceride sulfates, and sulfosuccinates, (c) nonionic detergents such as, for example, fatty amine oxides, fatty acid alkanolamides, and polyoxyethylenepolypropylene copolymers, (d) amphoteric detergents such as, for example, alkyl-β-aminopropionates, and 2-alkyl-imidazoline quaternary ammonium salts, and (e) mixtures thereof.

[0065] The parenteral formulations will typically contain from about 0.5% to about 25% by weight of the drug in solution. Preservatives and buffers may be used. In order to minimize or eliminate irritation at the site of injection, such compositions may contain one or more nonionic surfactants having a hydrophile-lipophile balance (HLB) of from about 12 to about 17. The quantity of surfactant in such formulations will typically range from about 5% to about 15% by weight. Suitable surfactants include polyethylene glycol sorbitan fatty acid esters, such as sorbitan monooleate and the high molecular weight adducts of ethylene oxide with a hydrophobic base, formed by the condensation of propylene oxide with propylene glycol. The parenteral formulations can be presented in unit-dose or multi-dose sealed containers, such as ampoules and vials, and can be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid excipient, for example, water, for injections, immediately prior to use. Extemporaneous injection solutions and suspensions can be prepared from sterile powders, granules, and tablets of the kind previously described.

[0066] The therapeutic agent can be made into suppositories by mixing with a variety of bases, such as emulsifying bases or water-soluble bases. Formulations suitable for vaginal administration can be presented as pessaries, tampons, creams, gels, pastes, foams, or spray formulas containing, in addition to the active ingredient, such carriers as are known in the art to be appropriate.

[0067] The exact formulation, route of administration and dosage can be chosen by the individual physician in view of the patient's condition. [See, e.g., Fingl et. al., in The Pharmacological Basis of Therapeutics, 1975, Ch. 1 p. I]. The attending physician can determine when to terminate, interrupt, or adjust administration due to toxicity, or to organ dysfunctions. Conversely, the attending physician can also adjust treatment to higher levels if the clinical response were not adequate, precluding toxicity. The magnitude of an administrated dose in the management of disorder of interest will vary with the severity of the disorder to be treated and the route of administration. The severity of the disorder can, for example, be evaluated, in part, by standard prognostic evaluation methods. The dose and perhaps dose frequency, can vary according to the age, body weight, and response of the individual patient. A program comparable to that discussed above can be used in veterinary medicine.

[0068] Use of pharmaceutically acceptable carriers to formulate the compounds herein disclosed for the practice of the invention into dosages suitable for systemic administration is within the scope of the invention. With proper choice of carrier and suitable manufacturing practice, the compositions relevant to the invention, in particular, those formulated as solutions, can be administered parenterally, such as by intravenous injection. The compounds can be formulated readily using pharmaceutically acceptable carriers well known in the art into dosages suitable for oral administration. Such carriers enable the compounds relevant to the invention to be formulated as tablets, pills, capsules, liquids, gels, syrups, slurries, tablets, dragees, solutions, suspensions and the like, for oral ingestion by a patient to be treated.

[0069] Agents intended to be administered intracellularly may be administered using techniques well known to those of ordinary skill in the art. For example, such agents may be encapsulated into liposomes, then administered as described above. Liposomes are spherical lipid bilayers with aqueous interiors. Molecules present in an aqueous solution at the time of liposome formation are incorporated into the aqueous interior. The liposomal contents are both protected from the external microenvironment and, because liposomes fuse with cell membranes, are efficiently delivered into the cell cytoplasm. Additionally, due to their hydrophobicity. small organic molecules may be directly administered intracellularly. Materials and methods described for one aspect of the invention can also be employed in other aspects of the invention. For example, a material such a nucleic acid or antibody described for use in screening assays can also be employed as therapeutic agents and vice versa.

[0070] The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.

EXAMPLE 1

[0071] This example demonstrates an example of an isolated sphingosine-1 - phosphate (SlP) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S 1 P3) in accordance with the invention. Polyclonal antiserum that specifically recognizes S 1P3 is produced.

[0072] Rabbits are immunized with a synthetically-generated peptide of the sequence KKTFSLSPTVWFLREG. This sequence is found in the extracellular loop of S1P3 between transmembrane domains 2 and 3. This primary sequence is unique and shares little similarity to the same motif in the other four known S I P-specific receptors. [0073] HEK293 cells are transiently transfected with constructs that overexpress the indicated receptor. A C-terminal epitope tag (V5) is used to verify transfection, expression, and appropriate plasma membrane localization. Cells are fixed with 4% paraformaldehyde, permeabilized with 0.1% Triton X-100, blocked with 2.5% bovine serum albumin, and exposed to the S1P3 antiserum at a concentration of 1 : 1,000. Bound antibody is detected with a Cy 3 -conjugated ant-rabbit antibody and visualized with fluorescence microscopy. Serum from the immunized rabbits specifically binds to HEK293 cells that overexpress S1 P3, but not to HEK293 cells that overexpress SlPl or Sl P2.

EXAMPLE 2

[0074] This example demonstrates that S1P3 is expressed in human breast tumor cell lines, cell lines that can be employed in the examples that follow and in the methods of the invention generally.

[0075] Quantitative real-time RT-PCR is performed to determine expression of the five known high affinity S I P-specific receptors (S 1 P1-S 1P5) in two breast cancer cell lines (MCF-7 and MDA-MB-231). Copy number is determined by standardization to samples of known concentrations, and represented relative to the house-keeping gene, cyclophilin A. Total RNA is isolated from cells using TRIZOL (Life Technologies) according to the manufacturer's protocol. After DNAse treatment (RNAse-free DNAse, Fermentas), RNA samples are reverse-transcribed into cDNA using oligo (dT) 12-18 and Super ScriptTM II Reverse transcriptase (Invitrogen). cDNA is amplified by Taq DNA Polymerase in 1OX PCR Buffer using the manufacturer's protocol. For quantification by real time RT-PCR, targets are amplified with iQ sybr green supermix (Bio-Rad cat# 170-8880) on a Bio-Rad iCycler. Copy number is determined by comparison to standard curves using plasmid templates containing reference sequences at known concentrations.

[0076] In both lines, S1 P3 is the most abundant species. S1 P4 and S 1P5 are not detected in either sample. TABLE 1 : mRNA Copy #/Copy Cyclophilin A (Xl 0-4)

[0077] In addition, cDNA prepared from an invasive ductal carcinoma from a 54 year-old female is amplified by non-quantitative RT-PCR with SlP3-specific primers that span an intron splice site. A band of the predicted size is obtained, thus verifying the expression of S1P3 in a clinically-derived breast tumor.

EXAMPLE 3

[0078] This example demonstrates the ability of an antagonist of the invention to have an anti-neoplastic effect such as the inhibition of cell proliferation and/or mobility. The effect measured is the ability of S lP to induce cytoskeletal rearrangement in breast cancer cells (BCCs).

[0079] The experiments can be first performed in the absence of the antagonist to demonstrate that S l P induces cytoskeletal rearrangement in BCCs. MDA-MB-231 breast cancer cells are cultured on collagen-coated coverslips in the presence of 10% FBS using standard techniques. Because SlP is present at high concentrations in serum, BCCs are "serum-starved" in Dulbecco's modified Eagle medium (DMEM) for 12 hours prior to experimental manipulation. SlP is solubilized with bovine serum albumin (BSA) carrier and administered at a final concentration of I nM to I uM. Coverslips are collected at representative time points such as 10 minutes, 1 hr., 2hrs., 4hrs., and 6hrs., fixed with 4% paraformaldehyde, and stained with rhodamine- conjugated phalloidin to label cytoskeletal actin. [0080] Upon application of 1 μM SlP to breast cancer cells in culture, marked cytoskeletal rearrangement is apparent in the majority of the cells (>90%) within 10 minutes. There is a near complete collapse of the cytoplasmic extensions and cell rounding. This morphological change persists for at least one hour. By two hours after administration, the cells begin to show signs of recovery with cell spreading and membrane ruffling. At four hours, most cells begin re-extending processes, and return to normal morphology by six hours. SlP is highly potent in its ability to elicit cytoskeletal rearrangement in BCCs by inducing cell rounding at low concentrations. There are minor cell shape changes at I nM and dramatic cell rounding at 1 OnM. This is significant in that the concentration of S l P in human serum is -10OnM, which is far greater than that needed to be functionally active.

[0081] The cell rounding experiment can be performed using an antagonist of SlP that binds to S1P3. For example, the antiserum described in Example 1 can be employed. Serum-starved MDA-MB-231 cells are incubated with preimmune serum or SlP3-reactive antiserum for 15 minutes prior to a 30-minute exposure to 1 OnM Sl P, then evaluated for response both in % cells responding and average cell area.

[0082] MDA-MB-231 cells are grown under standard culture conditions and serum starved for 24 hours prior to experimental manipulation. S1P3 antiserum or preimmune serum obtained from the same rabbit is added to the media at a final concentration of 1 : 10,000 as indicated. 15 minutes later, Sl P is added to the media to a final concentration of 1 OnM. 30 minutes after S l P administration, cells are fixed with 4% paraformaldehyde, stained with rhodamine-conjugated phalloidin, and visualized with fluorescence microscopy. Rounded cells are counted by an experimenter blinded to the identity of the sample. Cell area is determined by quantification with ImageJ software. Results are shown in Tables 2 and 3.

TABLE 2: % Rounded Cells Following SlP Treatment.

TABLE 3: Average Cell Area Following SlP Treatment (μm²)

[0083] The concentration of serum used (1 : 10,000) itself is not sufficient to induce cell rounding. While preimmune-treated cells respond to Sl P identically to untreated controls, antiserum-treated cells fail to respond and maintained the shape of cells not exposed to Sl P. This result is consistent with the model that the antiserum, and antagonists according to the invention generally, can block the effects of S l P on cancer cells.

EXAMPLE 4

[0084] This example demonstrates that an SlP antagonist in accordance with the invention can inhibit the induction by Sl P of cancer cell proliferation.

[0085] The experiment can first be performed in the absence of the antagonist. The effect of SlP on cell proliferation is determined by measuring bromodeoxyuridine (BrdU) incorporation. In this assay, cells are treated with SlP or vehicle control (0.1% fatty acid-free BSA) for 30 minutes before being exposed to a 30-minute BrdU pulse. Cells are then fixed with ethanol, labeled with a biotinylated α-BrdU antibody, incubated with streptavidin-peroxidase, developed with DAB, and counter-stained with hematoxylin. Nuclei of cells in S-phase during the 30-minute pulse are labeled brown, while non-proliferative cells show the blue hematoxylin stain. The results are shown in Table 4.

TABLE 4: Dose-Dependent Increase in Mitosis in Two Breast Cancer Cell Lines (MCF-7 and MDA-MB-231) by SlP as Determined By BrdU Incorporation

[0086J The presence of S l P causes a dose-dependent increase in mitosis in two breast cancer cell lines (MCF-7 and MDA-MB-231) as determined by BrdU incorporation. When the experiment is performed in the presence of one or more S1P3 antagonist of the invention that increase in mitosis is diminished or eliminated.

[0087] Determination of the effect of S 1 P3 blocking antibodies on the proliferation of cancer cells can be performed as follows. Cancer cells, including MCF-7 and MDA- MB-23 1 cells, are grown under standard conditions as adherent cell culture with Dulbecco's modified Eagle medium (DMEM) supplemented with 10% fetal bovine serum (FBS), glutamine, and penicillin/streptavidin. Cells are "serum-starved" for at least 12 hours prior to experimental manipulation by culturing in DMEM only. Cultures are then pre -treated with blocking anti-serum, or purified blocking antibodies. Control cultures are treated with pre-immune serum or with non-specific control antibodies. Cells arc then stimulated with S l P at varying concentrations (including InM, 1OnM, 10OnM, l μM, l OμM, or any intermediate concentration) or with FBS at varying concentrations (for example 1%, 5%. or 10%). Control cultures without stimulation are run in parallel.

[0088] Following a period of stimulation (usually .25, .5, .75, 1, 1 .5, 2, 3, 4, or some intermediate period) cells are pulsed with bromodeoxyuridine (BrdU) obtained from Invitrogen Corporation (Carlsbad, CA). The pulse period is usually 5, 10, 15, 30, 60, 90, or 120 minutes. Cells are then fixed with 70% ethanol for at least 20 minutes and labeled for the presence of incorporated BrdU with a commercial BrdU labeling kit obtained from Invitrogen Corporation (Carlsbad, CA). Alternatively, following fixation, cells are treated with HCl to gently denature the DNA, blocked with a solution containing bovine serum albumin, labeled with an unconjugated BrdU antibody (EMD Chemicals Inc., Gibbstown, NJ), and visualized with a fluorescent anti-mouse secondary antibody. Degree of proliferation is determined by counting the number of labeled cells as a percentage of total cells. Degree of proliferation in the presence of the blocking antibody is compared to the degree of proliferation found under the same stimulatory conditions in the absence of the antibody.

EXAMPLE 5

[0089] This example demonstrates that an Sl P antagonist in accordance with the invention can inhibit the induction of cancer cell migration by Sl P. The experiment can first be performed in the absence of the antagonist.

[0090] Cell motility is determined using a modified Boyden's chamber assay. MDA- MB-231 cells are introduced into the upper wells of collagen-coated chambers in serum-free DMEM and incubated for 30 minutes before the addition of either l μM Sl P in BSA or BSA alone. At the indicated times, wells are isolated and fixed with 4% paraformaldehyde before non-migrated cells in the upper well are removed with a cotton swab. Membranes are then stained with DAPI to visualize individual migrated cells on the bottom of the membranes. Results shown are the averages of three independent experiments.

TABLE 5: SlP Induces Cell Migration In Breast Cancer Cells. (Cells/mm²)

[0091] The administration of l μM S lP stimulated a rapid and significant increase in cell motility compared to vehicle control. Notably, there is a 74% increase in migrated cells within one hour of S l P administration, which grew to a nearly two-fold increase at the two hour time point. When the experiment is performed in the presence of one or more S1 P3 antagonist of the invention that increase in cell mobility is diminished or eliminated.

[0092] Determination of the effect of S 1 P3 blocking antibodies on the migration of cancer cells can be performed as follows. The effect of S 1 P3 blocking antibodies is determined using a modified Boyden chamber assay as described above. In this case, an appropriate cell line (such as MDA-MB-213) is seeded into the upper chamber of the transwell and pre-treated with a blocking antibody or control antibody. Blocking antibodies can be in the form of anti-serum, purified polyclonal antibodies, or purified or unpurified monoclonal antibodies. Control cells are treated with control antibodies that can be in the form of naϊve serum, pre-immune serum, purified non-specific polyclonal antibodies, or purified or unpurified non-specific monoclonal antibodies. Following an incubation period (usually 15 minutes to 1 hour) with the antibody or control antibody, cells are stimulated with SlP (usually I nM to lOμM) or with another known pro-migratory stimulus (for example, fetal bovine serum). The stimulatory period varies among the cell lines, but is generally between 1 and 12 hours. Cells are then fixed and counted as described above. The anti-migratory effect of the blocking antibody is determined by comparing the number of migrated cells in the presence of the antibody to the number of migrated cells in the presence of an appropriate control antibody under the same stimulatory conditions.

EXAMPLE 6

[0093] This example demonstrates that a S lP antagonist of the invention can sensitize cancer cells to chemotherapy toxicity.

[0094] The experiment can be performed first without a SlP antagonist. MDA-MB- 231 cells are cultured under standard conditions in Dulbecco's Minimal Essential Media supplemented with 10% fetal bovine serum and glutamate. Cells are grown in the absence of serum for 24 hours prior to experimental manipulation. Tamoxifen (Tarn) and S l P are added to the media at the indicated concentrations for the indicated times at the appropriate concentrations (e.g., 3μM Tarn, l OμM Tarn, and 20μM Tarn) for appropriate times (e.g., 6 hrs. and 24hrs.). Cell viability is observed by direct illumination with an inverted phase contrast microscope. [0095] MDA-MB-23 1 breast cancer cells cultured under low-density, serum-free conditions are healthy and adherent with visible processes although there are some rounded, dying cells present in the culture. After 6 hours of treatment with lOμM tamoxifen, only a few viable cells remain and all cells are dead/dying with 20μM tamoxifen, while many viable cells remain when media is supplemented with l μM SlP. Similarly, after a 24 hour treatment, most control cells are lost in the presence of 3μM tamoxifen and cell death is complete with lOμM tamoxifen, while the addition of S l P markedly improves survival.

[0096] The tamoxifen toxicity experiment can be performed using an antagonist of SlP that binds to S 1P3. For example, the antiserum described in Example 1 can be employed. MDA-MB-231 cells are cultured under standard conditions in Dulbecco's Minimal Essential Media supplemented with 10% fetal bovine serum and glutamate. Serum concentration is reduced to 1% for 24 hours prior to experimental manipulation. Tamoxifen and Sl P are added to the media at the appropriate concentrations (e.g., OμM Tarn, lOμM Tam, and 20μM Tarn) for appropriate times (e.g., 6 hrs. and 24hrs.). Cell viability is observed by direct illumination with an inverted phase contrast microscope.

[0097] Cells treated with Tam for 6 hours in the presence of 1% FBS appear normal at lOμM Tam and begin to show evidence of cell death at 20μM. However, coadministration of S1 P3 antiserum (1 : 1,000) greatly enhances the toxicity of Tam with increased cell death at lOμM, and nearly all cells lost or dying at 20μM. Similarly, after 24 hours, cell loss and cell death is apparent in the antiserum-treated cells at 5μM Tam, a concentration that shows no effect on pre-immune serum-treated cells. And at l OμM, dying cells are present, but most cells remain healthy under control conditions, however, few viable cells remain in the presence of antiserum-containing media.

[0098] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0099] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non- claimed element as essential to the practice of the invention.

[0100] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

ClaimsWhat is claimed is:

1. An isolated sphingosine-1 -phosphate (Sl P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1P3).

2. The antagonist of claim 1, wherein the amino acid sequence KKTFSLSPTVWFLREG comprises the epitope.

3. The antagonist of claim 1 or 2, wherein the antagonist is an antibody or a polypeptide comprising an antigen-binding fragment of the antibody.

4. The antibody or polypeptide of claim 3, wherein the antibody is a chimeric antibody.

5. The antibody or polypeptide of claim 3 or 4, wherein the antibody is a humanized antibody.

6. The antibody or polypeptide of claim 4 or 5, wherein the antibody is a completely humanized antibody.

7. The antibody or polypeptide of any one of claims 3-6, wherein the antibody is a monoclonal antibody.

8. The antibody or polypeptide of any one of claims 3-6, wherein the antibody is a polyclonal antibody.

9. The antagonist of claim 1 or 2, wherein the antagonist is an aptamer.

10. The aptamer of claim 9, wherein the aptamer comprises a nucleic acid.

1 1. The aptamer of claim 9 or 10, wherein the aptamer comprises RNA.

12. The aptamer of claim 9 or 10, wherein the aptamer comprises DNA.

13. The aptamer of claim 9, wherein the aptamer comprises an amino acid.

14. A composition comprising the antagonist of any one of claims 1 -13 and an anti-neoplastic agent.

15. The composition of claim 14, wherein the anti-neoplastic agent binds to an estrogen receptor.

16. The composition of claim 14 or 15, wherein the anti-neoplastic agent is selected from the group consisting of tamoxifen, toremifene, raloxifene, clomiphene, any prodrug thereof, any salt thereof, and any combination thereof.

17. The composition of any one of claims 14-16, wherein the antineoplastic agent is tamoxifen, a prodrug thereof, a salt thereof, or any combination thereof.

18. The composition of claim 14, wherein the anti-neoplastic agent is an antimetabolite, a prodrug thereof, a salt thereof, or any combination thereof.

19. The composition of claim 14 or 18, wherein the anti-neoplastic agent is selected from the group consisting of methotrexate, capecitabine, cladribine, cytarabine, fludarabine, fluorouracil, gemeitabine, mercaptopurine, thioguanine any prodrug thereof, any salt thereof, and any combination thereof.

20. The composition of claim 14, wherein the anti-neoplastic agent is a taxane, a prodrug, a salt thereof, or any combination thereof.

21. The composition of claim 14 or 20, wherein the anti-neoplastic agent is selected from the group consisting of paclitaxel, docetaxel, any prodrug thereof, any salt thereof, and any combination thereof.

22. The composition of claim 14, wherein the anti-neoplastic agent is an anthracycline, a salt thereof, a prodrug thereof, or any combination thereof.

23. The composition of claim 14 or 22, wherein the anti-neoplastic agent is selected from the group consisting of doxorubicin, daunorubicin, idarubicin, epirubicin, any prodrug thereof, any salt thereof, and any combination thereof.

24. The composition of claim 14, wherein the anti-neoplastic agent is a progestin, a prodrug thereof, a salt thereof, or any combination thereof.

25. The composition of claim 14 or 24, wherein the anti-neoplastic agent comprises megestrol, a prodrug thereof, a salt thereof, or any combination thereof.

26. The composition of claim 14, wherein the anti-neoplastic agent is an aromatase inhibitor, a prodrug thereof, a salt thereof, or any combination thereof.

27. The composition of claim 14 or 26, wherein the anti-neoplastic agent is selected from the group consisting of aminoglutethimide, anastrozole, letrozole, exemestane, any prodrug thereof, any salt thereof, and any combination thereof.

28. The composition of claim 14, wherein the anti-neoplastic agent binds to an epidermal growth factor receptor.

29. The composition of claim 14 or 28, wherein the anti-neoplastic agent is selected from the group consisting of gefitinib, cetuximab, lapatinib, erlotinib, trastuzumab, any prodrug thereof, any salt thereof, and any combination thereof.

30. A method of treating a cancer cell in a subject, the method comprising administering an effective amount of a first anti-neoplastic agent comprising the antagonist of any one of claims 1 -12 thereby treating the cancer cell in the subject.

31. The method of claim 30, the method further comprising administering an effective amount of a second anti-neoplastic agent, wherein the first anti-neoplastic agent enhances the efficacy of the second anti-neoplastic agent.

32. The method of claim 31 , wherein the enhancement is additive.

33. The method of claim 31 , wherein the enhancement is synergistic.

34. The method of any of claims 31-33, wherein the second anti-neoplastic agent binds to an estrogen receptor.

35. The method of claim 31-34, wherein the second anti-neoplastic agent is selected from the group consisting of tamoxifen, loremifene, raloxifene, clomiphene, any prodrug thereof, any salt thereof, and any combination thereof.

36. The method of any one of claims 31 -35, wherein the second antineoplastic agent is tamoxifen, a prodrug, a salt thereof, or any combination thereof.

37. The method of any one of claims 31 -36, wherein the first and second anti-neoplastic agents are administered by administering the composition of any one of claims 14-17.

38. The method of any of claims 31 -33, wherein the second anti-neoplastic agent binds to an epidermal growth factor receptor.

39. The method of any one of claims 3 1 -33 and 38, wherein the antineoplastic agent is selected from the group consisting of gefitinib, cetuximab, lapatinib, erlotinib, trastuzumab, any prodrug thereof, any salt thereof, and any combination thereof.

40. The method of any one of claims 31 -33, 38, and 39, wherein the first and second anti-neoplastic agents are administered by administering the composition of any one of claims 14, 28, and 29.

41. The method of any one of claims 31-33. wherein the first and second anti-neoplastic agents are administered by administering the composition of any one of claims 14 and 18-27.

42. The method of any one of claims 30-41 , wherein the treating comprises antagonizing one or more of the following: proliferation of the cell, remodeling of the cell, migration of the cell, invasion by the cell, and survival of the cell.

43. The method of any one of claims 30-42, wherein the cell is selected from the group consisting of a breast cancer cell, a colorectal cancer cell, a cervical cancer cell, an endometrial cancer cell, an ovarian cancer cell, a prostate cancer cell, a lung cancer cell, a glioblastoma cell, and any combination thereof.

44. The method of any one of claims 30-43, wherein the cancer cell is a breast cancer cell.

45. A method for identifying a test agent that enhances the efficacy of an anti-neoplastic agent in antagonizing a neoplastic cell, the method comprising: providing a first sample comprising a neoplastic cell; providing a second sample comprising a neoplastic cell; applying the anti-neoplastic agent to the first and second samples; applying the test agent to the second sample; assaying the first and second samples for an anti-neoplastic effect; and identifying whether the test agent is an enhancer based on the effect measured in the second sample compared to the effect measured in the first sample, wherein the test agent is an isolated sphingosine-1 -phosphate (Sl P) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1P3).

46. The method of claim 45, wherein the amount of anti-neoplastic agent applied to the first and second samples is the same, and the effect measured in the second sample is greater than the effect measured in the first sample.

47. The method of claim 46, wherein the enhancement of the effect is additive.

48. The method of claim 46, wherein the enhancement of the effect is synergistic.

49. The method of claim 45, wherein the amount of antineoplastic agent applied to the second sample is less that the amount of the anti-neoplastic agent applied to the first sample, and the effect measured in the first and the second samples is substantially the same.

50. The method of any one of claims 45-49, wherein the test agent is an antagonist of any one of claims 2-12.

51 . The method of any one of claims 45-50, wherein the neoplastic cell is selected from the group consisting of a breast cancer cell, a colorectal cancer cell, a cervical cancer cell, an endometrial cancer cell, an ovarian cancer cell, a prostate cancer cell, a lung cancer cell, a glioblastoma cell, and any combination thereof.

52. The method of any one of claims 45-51 , wherein the neoplastic cell is a breast cancer cell.

53. The method of any of claims 45-52, wherein the anti-neoplastic agent binds to an estrogen receptor.

54. The method of any one of claims 45-53, wherein the anti-neoplastic agent is selected from the group consisting of tamoxifen, toremifene, raloxifene, clomiphene, any prodrug thereof, any salt thereof, and any combination thereof.

55. The method of any one of claims 45-54, wherein the anti-neoplastic agent is tamoxifen.

56. The method of any of claims 45-52, wherein the anti-neoplastic agent binds to an epidermal growth factor receptor.

57. The method of any one of claims 45-52 and 56, wherein the antineoplastic agent is selected from the group consisting of gefitinib, cetuximab, lapatinib, erlotinib, trastuzumab, any prodrug thereof, any salt thereof, and any combination thereof.

58. The method of any one of claims 45-57, wherein the anti-neoplastic effect comprises at least one of cell stabilization, cell death, growth inhibition, cytoskeletal stabilization, and migration inhibition.

59. The method of claim 58, wherein the cytoskeletal stabilization comprises a decrease in process retraction, cell surface area reduction, rounding, or any combination thereof.

60. Use of an isolated sphingosine-1 -phosphate (SlP) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1 -phosphate receptor subtype 3 (S1P3) to treat a cancer cell in a subject.

61. Use of an isolated sphingosine-1-phosphate (S lP) antagonist that selectively binds to an epitope in the extracellular loop between transmembrane domains two and three of sphingosine-1-phosphate receptor subtype 3 (S 1P3) for the manufacture of a medicament to treat cancer.

62. A kit comprising the antagonist of any one of claims 1- 13 and an antineoplastic agent.

63. The kit of claim 62, wherein the antineoplastic agent is selected from the group consisting of an estrogen receptor binder, an antimetabolite, a taxane, an anthracycline, progestin, a megestrol, an aromatase inhibitor, an epidermal growth factor inhibitor, any prodrug thereof, any salt thereof, and any combination thereof.