Endotheliase-2 ligands

Abstract

Proteins that bind to ET2, such as immunoglobulins that inhibit ET2 with high affinity and selectivity, are provided. The ET2 binding proteins can be used to treat a variety of disorders, including angiogenesis-associated disorders.

1 . A method of modulating an activity of an endotheliase 2 (ET2)-expressing cell, the method comprising: contacting an ET2-expressing cell with a protein, wherein the protein comprises a heavy chain (HC) immunoglobulin variable domain sequence and a light chain (LC) immunoglobulin variable domain sequence, wherein 
 (1) the first and second immunoglobulin variable domain sequences form an antigen binding site that specifically binds to human ET2; and    (2) the protein has one or more of the following characteristics: 
 (a) the protein inhibits ET2 with an inhibition constant (Ki) of less than 300 nM;  
 (b) the HC immunoglobulin variable domain sequence comprises one or more CDRs that are at least 85% identical to a CDR of a HC variable domain of A10, G3, A6, A7, C8, H9, G10-R2, F3-R2, C6-R2, A4-R3, C1-R3, A2, B5, D2, D5, F8, H10, or C9;  
 (c) the LC immunoglobulin variable domain sequence comprises one or more CDRs that are at least 85% identical to a CDR of a LC variable domain of A10, G3, A6, A7, C8, H9, G10-R2, F3-R2, C6-R2, A4-R3, C1-R3, A2, B5, D2, D5, F8, H10, or C9;  
 (d) the LC immunoglobulin variable domain sequence is at least 85% identical to a LC variable domain of A10, G3, A6, A7, C8, H9, G10-R2, F3-R2, C6-R2, A4-R3, C1-R3, A2, B5, D2, D5, F8, H10, or C9;  
 (e) the HC immunoglobulin variable domain sequence is at least 85% identical to a HC variable domain of A10, G3, A6, A7, C8, H9, G10-R2, F3-R2, C6-R2, A4-R3, C1-R3, A2, B5, D2, D5, F8, H10, or C9; and  
 (f) the protein binds an epitope that overlaps with an epitope bound by A10, G3, A6, A7, C8, H9, G10-R2, F3-R2, C6-R2, A4-R3, C1-R3, A2, B5, D2, D5, F8, H10, or C9;  
   thereby modulating the activity of the ET2-expressing cell.    
     
     
         2 . The method of  claim 1 , wherein the ET2-expressing cell is in a human subject.  
     
     
         3 . The method of  claim 1 , wherein the protein prevents binding of the ET2-expressing cell to a substrate.  
     
     
         4 . The method of  claim 1 , wherein the cell is a cancer cell.  
     
     
         5 . The method of  claim 1 , wherein the protein binds to the ET2 active site.  
     
     
         6 . The method of  claim 1 , wherein the protein inhibits ET2 enzymatic activity.  
     
     
         7 . The method of  claim 1 , wherein the protein accumulates at sites of angiogenesis in vivo.  
     
     
         8 . The method of  claim 1 , wherein the protein inhibits proteolysis of vessel basement membrane.  
     
     
         9 . The method of  claim 1 , wherein the protein inhibits angiogenesis in vitro or in vivo.  
     
     
         10 . The method of  claim 1 , wherein the HC and LC variable domain sequences are components of the same polypeptide chain.  
     
     
         11 . The method of  claim 1 , wherein the HC and LC variable domain sequences are components of different polypeptide chains.  
     
     
         12 . The method of  claim 1 , wherein the protein is a full-length antibody.  
     
     
         13 . The method of  claim 1 , wherein the antibody is a human or humanized antibody.  
     
     
         14 . The method of  claim 1 , wherein the protein comprises a human antibody framework region.  
     
     
         15 . The method of  claim 1 , wherein the protein comprises an Fc domain.  
     
     
         16 . The method of  claim 1 , wherein the HC variable domain sequence comprises SEQ ID NO:89 and the LC variable domain sequence comprises SEQ ID NO:90.  
     
     
         17 . The method of  claim 1 , wherein the protein reduces tumor growth in a SCID mouse model.