NGR receptor and methods of identifying tumor homing molecules that home to angiogenic vasculature using same

Abstract

The present invention provides a method of identifying a tumor homing molecule that homes to angiogenic vasculature by contacting a substantially purified NGR receptor with one or more molecules and determining specific binding of a molecule to the NGR receptor, where the presence of specific binding identifies the molecule as a tumor homing molecule that homes to angiogenic vasculature. The invention also provides a method of directing a moiety to angiogenic vasculature in a subject by administering to the subject a conjugate including a moiety linked to a tumor homing molecule that exhibits specific binding to an NGR receptor, whereby the moiety is directed to angiogenic vasculature. In addition, the invention provides a method of imaging the angiogenic vasculature of a tumor in a subject by administering to the subject a conjugate having a detectable moiety linked to a tumor homing molecule that exhibits specific binding to an NGR receptor and detecting the conjugate.

We claim:  
     
         1 . A method of identifying a tumor homing molecule that homes to angiogenic vasculature of a tumor, comprising: 
 (a) contacting a substantially purified NGR receptor with one or more molecules; and    (b) determining specific binding of a molecule to said NGR receptor,    wherein the presence of specific binding identifies said molecule as a tumor homing molecule that homes to angiogenic vasculature of a tumor.    
     
     
         2 . The method of  claim 1 , further comprising the steps of: 
 (c) administering an NGR binding molecule in vivo; and    (d) determining binding of said NGR binding molecule to angiogenic vasculature of a tumor.    
     
     
         3 . The method of  claim 1 , wherein said substantially purified NGR receptor is CD13/aminopeptidase N.  
     
     
         4 . The method of  claim 1 , wherein said substantially purified NGR receptor is immobilized to a support.  
     
     
         5 . A method of identifying a homing molecule that homes to angiogenic vasculature, comprising: 
 (a) contacting a substantially purified NGR receptor with one or more molecules; and    (b) determining specific binding of a molecule to said NGR receptor,    wherein the presence of specific binding identifies said molecule as a homing molecule that homes to angiogenic vasculature.    
     
     
         6 . The method of  claim 5 , further comprising the steps of: 
 (c) administering an NGR binding molecule in vivo; and    (d) determining binding of said NGR binding molecule to angiogenic vasculature.    
     
     
         7 . The method of  claim 5 , wherein said substantially purified NGR receptor is CD13/aminopeptidase N.  
     
     
         8 . The method of  claim 5 , wherein said substantially purified NGR receptor is immobilized to a support.  
     
     
         9 . A method of directing a moiety to angiogenic vasculature of a tumor in a subject, comprising administering to the subject a conjugate comprising a moiety linked to a tumor homing molecule that exhibits specific binding to an NGR receptor, whereby the moiety is directed to angiogenic vasculature of a tumor.  
     
     
         10 . The method of  claim 9 , wherein said tumor homing molecule is a peptide containing the sequence NGR.  
     
     
         11 . The method of  claim 10 , wherein said moiety is a cytotoxic agent.  
     
     
         12 . The method of  claim 10 , wherein said moiety is a drug.  
     
     
         13 . The method of  claim 12 , wherein said drug is a cancer chemotherapeutic agent.  
     
     
         14 . The method of  claim 13 , wherein said cancer chemotherapeutic agent is doxorubicin.  
     
     
         15 . The method of  claim 10 , wherein said tumor homing peptide comprises a sequence selected from the group consisting of CNGRCVSGCAGRC (SEQ ID NO:3), NGRAHA (SEQ ID NO:6), CVLNGRMEC (SEQ ID NO:7), and CNGRC (SEQ ID NO:8).  
     
     
         16 . The method of  claim 15 , wherein said moiety is a cytotoxic agent.  
     
     
         17 . The method of  claim 15 , wherein said moiety is a drug.  
     
     
         18 . The method of  claim 17 , wherein said drug is a cancer chemotherapeutic agent.  
     
     
         19 . The method of  claim 18 , wherein said cancer chemotherapeutic agent is doxorubicin.  
     
     
         20 . The method of  claim 9 , wherein said tumor homing molecule is an inhibitor of a CD13-like aminopeptidase.  
     
     
         21 . The method of  claim 20 , wherein said inhibitor is selected from the group consisting of bestatin, actinonin and o-phenanthroline.  
     
     
         22 . The method of  claim 21 , wherein said moeity is a cytotoxic agent.  
     
     
         23 . The method of  claim 21 , wherein said moiety is a drug.  
     
     
         24 . The method of  claim 23 , wherein said drug is a cancer chemotherapeutic agent.  
     
     
         25 . The method of  claim 24 , wherein said cancer chemotherapeutic agent is doxorubicin.  
     
     
         26 . A method of inhibiting angiogenesis in a tumor of a subject, comprising administering to the subject a conjugate comprising a moiety linked to a tumor homing molecule that exhibits specific binding to an NGR receptor, whereby the moiety is directed to angiogenic vasculature.  
     
     
         27 . The method of  claim 26 , wherein said tumor homing molecule is a peptide containing the sequence NGR.  
     
     
         28 . The method of  claim 27 , wherein said moiety is a cytotoxic agent.  
     
     
         29 . The method of  claim 27 , wherein said moiety is a drug.  
     
     
         30 . The method of  claim 29 , wherein said drug is a cancer chemotherapeutic agent.  
     
     
         31 . The method of  claim 30 , wherein said cancer chemotherapeutic agent is doxorubicin.  
     
     
         32 . The method of  claim 27 , wherein said tumor homing peptide comprises a sequence selected from the group consisting of CNGRCVSGCAGRC (SEQ ID NO:3), NGRAHA (SEQ ID NO:6), CVLNGRMEC (SEQ ID NO:7), and CNGRC (SEQ ID NO:8).  
     
     
         33 . The method of  claim 32 , wherein said moiety is a cytotoxic agent.  
     
     
         34 . The method of  claim 32 , wherein said moiety is a drug.  
     
     
         35 . The method of  claim 34 , wherein said drug is a cancer chemotherapeutic agent.  
     
     
         36 . The method of  claim 35 , wherein said cancer chemotherapeutic agent is doxorubicin.  
     
     
         37 . The method of  claim 26 , wherein said tumor homing molecule is an inhibitor of a CD13-like aminopeptidase.  
     
     
         38 . The method of  claim 37 , wherein said inhibitor is selected from the group consisting of bestatin, actinonin and o-phenanthroline.  
     
     
         39 . The method of  claim 37 , wherein said moiety is a cytotoxic agent.  
     
     
         40 . The method of  claim 37 , wherein said moiety is a drug.  
     
     
         41 . The method of  claim 40 , wherein said drug is a cancer chemotherapeutic agent.  
     
     
         42 . The method of  claim 41 , wherein said cancer chemotherapeutic agent is doxorubicin.  
     
     
         43 . A method of imaging the angiogenic vasculature of a tumor in a subject, comprising: 
 (a) administering to the subject a conjugate comprising a detectable moiety linked to a tumor homing molecule that exhibits specific binding to an NGR receptor,    whereby said conjugate specifically binds said angiogenic vasculature; and    (b) detecting said conjugate.    
     
     
         44 . The method of  claim 43 , wherein said detectable moiety is a radionuclide.  
     
     
         45 . The method of  claim 43 , wherein said tumor homing molecule is a peptide containing the sequence NGR.  
     
     
         46 . The method of  claim 45 , wherein said tumor homing peptide comprises a sequence selected from the group consisting of CNGRCVSGCAGRC (SEQ ID NO:3), NGRAHA (SEQ ID NO:6), CVLNGRMEC (SEQ ID NO:7), and CNGRC (SEQ ID NO:8).  
     
     
         47 . The method of  claim 46 , wherein said detectable moiety is a radionuclide.  
     
     
         48 . The method of  claim 47 , wherein said radionuclide is selected from the group consisting of indium-111, technitium-99, carbon-11 and carbon-13.  
     
     
         49 . The method of  claim 43 , wherein said tumor homing molecule is an inhibitor of a CD13-like aminopeptidase.  
     
     
         50 . The method of  claim 49 , wherein said inhibitor is selected from the group consisting of bestatin, actinonin and o-phenanthroline.  
     
     
         51 . The method of  claim 49 , wherein said detectable moiety is a radionuclide.  
     
     
         52 . The method of  claim 51 , wherein said radionuclide is selected from the group consisting of indium-111, technitium-99, carbon-11 and carbon-13.  
     
     
         53 . A substantially purified target molecule, comprising a NGR receptor that binds a peptide comprising the sequence NGR, provided that said NGR receptor does not have the amino acid sequence of CD13/aminopeptidase N (SEQ ID NO:201).