Erg monoclonal antibodies

Abstract

Monoclonal antibodies, or antigen-binding fragments thereof, that bind to ERG, and more specifically, to an epitope formed by amino acids 42-66 of ERG3 are disclosed. The monoclonal antibodies can be non-human antibodies (e.g., rabbit or mouse) or humanized monoclonal antibodies having the CDR regions derived from those non-human antibodies. In other embodiments, the monoclonal antibodies are chimeric, having the light and heavy chain variable regions of a non-human ERG antibody. Methods of using the antibodies to detect ERG, or fusion proteins comprising all or part of an ERG polypeptide, such as an ERG polypeptide encoded by a TMPRSS2/ERG, SLC45A3/ERG, or NDRG1/ERG fusion transcript, are also provided, including methods of detecting ERG or ERG fusion events in a clinical setting. The antibodies can also be used to inhibit the activity of ERG or fusion proteins comprising all or part of an ERG polypeptide, such as an ERG polypeptide encoded by a TMPRSS2/ERG, SLC45A3/ERG, or NDRG1/ERG fusion transcript and to treat malignancies associated with overexpression of ERG or an ERG fusion event, such as prostate cancer, Ewing's sarcoma, acute myeloid leukemia, acute T-lymphoblastic leukemia, endothelial cancer, and colon cancer.

1 . A monoclonal antibody that binds an epitope formed by amino acids 42-66 of SEQ ID NO:1. 
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . The monoclonal antibody of  claim 1 , wherein said antibody competes with a polypeptide consisting of amino acids 42-66 for binding to a polypeptide having the amino acid sequence of SEQ ID NO: 1. 
     
     
         5 . The monoclonal antibody of  claim 1 , wherein said antibody competitively inhibits the binding of an antibody having a light chain variable domain comprising the amino acid sequence of SEQ ID NO:2 and a heavy chain variable domain comprising the amino acid sequence of SEQ ID NO:3 to a polypeptide having the amino acid sequence of SEQ ID NO:1. 
     
     
         6 . A method of detecting human ERG or a fusion protein comprising all or part of a human ERG polypeptide in a biological sample, wherein the method comprises contacting the monoclonal antibody of  claim 1  with the biological sample and analyzing the biological sample to detect binding of the monoclonal antibody to human ERG or the fusion protein comprising all or part of the human ERG polypeptide in the biological sample. 
     
     
         7 . The method of  claim 6 , wherein the biological sample comprises a tissue or a cell. 
     
     
         8 . The method of  claim 7 , wherein the tissue or the cell is a prostate tissue or a prostate cell. 
     
     
         9 . The method of  claim 6 , wherein the fusion protein is an ERG protein encoded by a TMPRSS2/ERG fusion transcript. 
     
     
         10 . A composition comprising a polypeptide having no more than 60 amino acid residues, wherein the polypeptide includes amino acid residues 42-66 of SEQ ID NO:1. 
     
     
         11 . The composition of  claim 10 , wherein the polypeptide has no more than 40 amino acid residues. 
     
     
         12 . The composition of  claim 10 , wherein the polypeptide has no more than 25 amino acid residues. 
     
     
         13 . The composition of  claim 10 , further comprising an adjuvant. 
     
     
         14 . The composition of  claim 10 , further comprising a hapten coupled to the polypeptide. 
     
     
         15 . The composition of  claim 10 , further comprising a pharmaceutically acceptable excipient. 
     
     
         16 . A method of generating a monoclonal antibody that binds to the ERG 42-66 epitope, comprising administering the composition of  claim 10  to a non-human mammal, isolating B cells from the non-human mammal, immortalizing the B cells to create a cell line capable of producing a monoclonal antibody, and selecting the monoclonal antibody that binds to the ERG 42-66 epitope. 
     
     
         17 . A method for identifying a nucleic acid molecule or polypeptide that interacts with an ERG polypeptide, comprising incubating a sample comprising the nucleic acid molecule or the polypeptide with the ERG polypeptide, incubating the sample and the ERG polypeptide with the monoclonal antibody of  claim 1 , and determining whether a complex forms between the nucleic acid molecule and the ERG polypeptide or between the polypeptide and the ERG polypeptide, wherein detecting the formation of a complex with the antibody indicates that the nucleic acid molecule or the polypeptide interacts with the ERG polypeptide. 
     
     
         18 . The monoclonal antibody of  claim 1 , wherein the antibody does not cross react with the human Fli1 protein. 
     
     
         19 . The monoclonal antibody of  claim 1 , wherein the antibody is conjugated to a detectable moiety. 
     
     
         20 . The monoclonal antibody of  claim 1 , wherein the antibody is bound to a secondary antibody and the secondary antibody is conjugated to a detectable moiety.