Methods and uses thereof of prosaposin

Abstract

The invention relates to methods for treating of tumor metastasis, methods for preventing, inhibiting, and predicting tumor recurrence and tumor metastasis, and methods of preventing cancer development for one at risk of developing cancer, for one diagnosed with a benign cancer, and/or for one diagnosed with malignant cancer. The invention also relates to methods of treating angiogenesis-dependent diseases and disorders. In addition, the invention provides: (1) a method for screening for tumor/cancer derived angiogenesis and metastasis factors; (2) a method for screening for compounds that inhibit angiogenesis and metastasis; (3) a method for screening for compounds that promote anti-angiogenesis and anti-metastasis activities; (4) a method for cancer prognosis evaluation; (5) a method for predicting the tissue specificity of a metastatic cancer; (6) a method for determining likelihood of metastasis; and (7) a method for cancer prognosis evaluation by the surveillance of metastasis development.

1 . A method of treating an angiogenesis-dependent disease or disorder, comprising administering to a subject in need of treatment thereof, a therapeutically effective amount of Psap protein or a vector comprising a nucleic acid encoding Psap protein and a pharmaceutically acceptable carrier. 
     
     
         2 . A method of inhibiting the recurrence of an angiogenesis-dependent disease or disorder, the method comprises administering to a subject in need thereof, a therapeutically effective amount of a Psap protein or a vector comprising the nucleic acid encoding a Psap protein, and a pharmaceutically acceptable carrier. 
     
     
         3 . A method of inhibiting metastasis of cancer in a subject diagnosed with cancer, the method comprises administering to a subject in need thereof, a therapeutically effective amount of a Psap protein or a vector comprising the nucleic acid encoding a Psap protein, and a pharmaceutically acceptable carrier. 
     
     
         4 . The method of  claim 1  or  2 , wherein the angiogenesis-dependent disease or disorder is selected from a group consisting of cancer, psoriasis, age-related macular degeneration, thyroid hyperplasia, preeclampsia, rheumatoid arthritis and osteoarthritis, Alzheimer's disease, obesity, pleura effusion, atherosclerosis, endometriosis, diabetic/other retinopathies, neovascular glaucoma, age-related macular degeneration, hemangiomas, and corneal neovascularization. 
     
     
         5 . The method of  claim 1 ,  2 , or  3 , wherein the subject is diagnosed with a benign or malignant cancer. 
     
     
         6 . The method of  claim 1   2 , or  3 , wherein the Psap protein is saposin A (SEQ. ID. No. 13) or smaller functional fragments thereof. 
     
     
         7 . The method of  claim 1 ,  2 , or  3 , wherein the Psap protein is a fragment or variant of saposin A that at least 10 amino acid residues and is capable of activating p53 and inducing Tsp-1 expression. 
     
     
         8 . The method of  claim 1 ,  2 , or  3 , wherein the Psap protein is a fragment or variant of saposin A that is fused to a second protein or portions thereof, wherein the second protein is not a Psap protein. 
     
     
         9 . The method of  claim 1 ,  2 , or  3 , wherein the Psap protein is a fragment or variant of saposin A that is fused/conjugated to a therapeutic molecule. 
     
     
         10 . A method for prognostic evaluation of an individual diagnosed with cancer comprising:
 a. determining the level of Psap expression in a tumor sample from an individual diagnosed with cancer;   b. comparing the level determined in step (a) to a reference Psap level from a non-tumor sample from the individual;   wherein when said level of Psap in the tumor sample is lower than a reference Psap level, there is an increased likelihood of cancer metastasis and/or recurrence of neoplastic disease, and thus a poor prognosis.   
     
     
         11 . The method of  claim 10 , further comprising:
 a. determining the level of Tsp-1 expression in a tumor stroma; and   b. comparing the levels of steps (a) with reference level of Tsp-1;   wherein when the level of Tsp-1 in the tumor stroma are lower than a reference of Tsp-1 level respectively, there is an increased likelihood of cancer metastasis and/or recurrence of neoplastic disease, and thus a poor prognosis.   
     
     
         12 . A method of treating an individual diagnosed with cancer comprising:
 a. determining a level of Psap in a tumor sample from said individual;   b. comparing the Psap level determined in (a) with a reference Psap level; and   when said Psap level determined in (a) is lower than 95% of said reference Psap level, administering a therapeutically effective amount of Psap protein or a vector comprising a nucleic acid encoding Psap protein and a pharmaceutically acceptable carrier.   
     
     
         13 . The method of  claim 12 , wherein the Psap protein is saposin A (SEQ. ID. No. 13) or fragment or variant thereof. 
     
     
         14 . The method of  claim 13 , wherein the fragment or variant of saposin A is at least 10 amino acid residues and is capable of activating p53 and inducing Tsp-1 expression. 
     
     
         15 . The method of  claim 13 , wherein the smaller functional fragment or variant of saposin A is fused to a second protein or portions thereof, wherein the second protein is not a Psap protein. 
     
     
         16 . The method of  claim 12 , wherein the treatment is administered in conjunction with chemotherapy, radiation therapy, a cytostatic agent, an anti-VEGF agent, an anti-angiogenesis factor, and/or a p53 reactivation agent. 
     
     
         17 . A method of screening and identifying tumor secreted factors that promote angiogenesis and metastasis comprising:
 a. contacting fibroblasts and/or endothelial cells with a cancer cell derived factor;   b. determining the levels of angiogenic growth factors and/or angiogenesis inhibitors; and   c. comparing the levels of step (b) with reference levels of angiogenic growth factors and/or angiogenesis inhibitor;
 wherein a decrease in the level of an angiogenesis inhibitor and/or an increase in the level of angiogenic growth factors in comparison to the respective reference levels indicate that the cancer cell derived factor contains factors that promote angiogenesis and metastasis. 
   
     
     
         18 . A method of predicting the metastatic tissue specificity of cancer cells in an individual diagnosed with cancer comprising:
 a. contacting fibroblasts and/or endothelial cells with a cancer cell derived factor;   b. determining the levels of Tsp-1, Psap, and/or c-Myc in the fibroblasts and/or endothelial cells; and   c. comparing the levels of step (b) to the reference levels of Tsp-1, Psap, and c-Myc of fibroblasts and/or endothelial cells not treated with cancer cell derived factors;   wherein repression of Tsp-1 and Psap expressions, and/or an activation of c-Myc expression in the treated fibroblasts and/or endothelial cells indicate that cancer is likely to metastasize to the type of tissue from which said fibroblast and/or endothelial cells had originated.   
     
     
         19 . A method for determining the likelihood of metastasis an individual diagnosed with cancer comprising:
 a. determining the level of Psap expression in a sample from an individual diagnosed with cancer;   b. comparing the Psap level of step (a) to a reference level of Psap;
 wherein when the level of Psap in the sample is same or lower than the reference Psap level, there is an increased likelihood of cancer metastasis. 
   
     
     
         20 . An isolated chimeric polypeptide comprising a first portion and a second portion, wherein said first portion is saposin A (SEQ. ID. No. 13) or a functional fragment thereof, and said second portion wherein said second portion is not a Psap protein, and wherein said first portion is capable of activating p53 and inducing Tsp-1 expression. 
     
     
         21 . The isolated chimeric polypeptide of  claim 20 , wherein the second portion comprises an amino acid sequence or a polymer that enhances the serum half life of said first portion. 
     
     
         22 . The isolated chimeric polypeptide of  claim 20 , wherein the second portion is a therapeutic molecule. 
     
     
         23 . A composition comprising of a peptide consisting essentially of the sequence CDWLPKPNMSASC (SEQ. ID. No. 37) and a pharmaceutically acceptable carrier. 
     
     
         24 . A method of treating an angiogenesis-dependent disease or disorder, comprising administering to a subject in need thereof, a therapeutically effective amount of a composition comprising of a peptide consisting essentially of the sequence CDWLPKPNMSASC (SEQ. ID. No. 37) and a pharmaceutically acceptable carrier.