Epidermal Growth Factor Receptor Antagonists and Methods of Use

Abstract

The present invention features epidermal growth factor receptor (EGFR) antagonists. These EGFR antagonists are polypeptide variants of ligands of EGFR. The EGFR ligand polypeptide variants of the invention possess EGFR antagonistic properties and can inhibit at least one EGFR-mediated biological activity such as inhibition of the receptor's kinase activation activity and subsequently, cell proliferation. Such polypeptide variants, and nucleic acids encoding these polypeptide variants can be used therapeutically in situations in which inhibition of EGFR activity is indicated.

1 - 4 . (canceled) 
     
     
         5 . An EGFR ligand polypeptide variant characterized by at least one amino acid substitution, deletion or insertion that prevents the variant from binding Domain III of EGFR and, optionally, at least one amino acid substitution, deletion or insertion that results in the variant binding to Domain I of EGFR, wherein the variant is an EGFR antagonist. 
     
     
         6 . The variant of  claim 5  characterized by a substitution, deletion or insertion that forms hydrophobic, electrostatic, or hydrogen bonds between one or more amino acids of the antagonist and EGFR. 
     
     
         7 . The variant of  claim 5 , wherein the variant is not substantially displaced from EGFR by EGF. 
     
     
         8 . The variant of  claim 5  characterized by an amino acid sequence substantially the same as the wild-type EGFR ligand. 
     
     
         9 . The variant of  claim 8 , wherein the EGFR ligand is EGF. 
     
     
         10 . An epidermal growth factor polypeptide variant in which the amino acid position that corresponds to amino acid Gly 18, amino acid Val 35, amino acid Arg 41 or amino acid Gly 39 of human wild-type epidermal growth factor is substituted with another amino acid, the polypeptide having epidermal growth factor receptor antagonist activity. 
     
     
         11 . The epidermal growth factor polypeptide variant of  claim 10 , wherein the polypeptide variant is a human EGF polypeptide variant. 
     
     
         12 . The epidermal growth factor polypeptide variant of  claim 10 , wherein the amino acid substitution at the position that corresponds to Gly 18 or Gly 39 of human wild-type epidermal growth factor is selected from the group consisting of: phenylalanine, leucine, aspartic acid, and isoleucine. 
     
     
         13 . The epidermal growth factor polypeptide variant of  claim 10 , wherein the amino acid corresponding to Val 35 of human wild-type epidermal growth factor is substituted with glutamate. 
     
     
         14 . The epidermal growth factor polypeptide variant of  claim 10 , wherein said polypeptide comprises at least one additional amino acid substitution at a position other than Gly 18 or Gly 39, said polypeptide having epidermal growth factor receptor antagonist activity. 
     
     
         15 . The epidermal growth factor polypeptide variant of  claim 14 , wherein said polypeptide comprises at least one additional amino acid substitution at Val 35 with glutamate. 
     
     
         16 . The epidermal growth factor polypeptide variant of  claim 14 , wherein said at least one amino acid substitution is a conservative amino acid substitution. 
     
     
         17 . The epidermal growth factor polypeptide variant of  claim 10 , wherein said polypeptide comprises at least one deletion of an amino acid at a position other than Gly 18 or Gly 39, said polypeptide having epidermal growth factor receptor antagonist activity. 
     
     
         18 . The epidermal growth factor polypeptide variant of  claim 10 , wherein said polypeptide comprises at least one insertional mutation of an amino acid at a position other than Gly 18 or Gly 39, said polypeptide having epidermal growth factor receptor antagonist activity. 
     
     
         19 . An epidermal growth factor polypeptide variant of human EGF in which the amino acid position that corresponds to amino acid Val 35 is substituted with glutamate and the amino acid Gly 39 is substituted with leucine. 
     
     
         20 . A pharmaceutical composition comprising the EGFR ligand polypeptide variant of  claim 5  and a pharmaceutically acceptable carrier. 
     
     
         21 . A method of treating a patient with a disease characterized by overexpression of EGFR comprising, administering to the patient, a therapeutically effective amount of a pharmaceutical composition of  claim 20 . 
     
     
         22 . The method of  claim 21  wherein the disease is cancer. 
     
     
         23 . The method of  claim 21  wherein the cancer is selected from the group consisting of gliomas, squamous cell carcinomas, breast carcinomas, melanomas, invasive bladder carcinomas, colorectal carcinomas and esophageal cancers. 
     
     
         24 . The method of  claim 21  wherein the disease is psoriasis. 
     
     
         25 . A polypeptide variant of an epidermal growth factor receptor ligand in which the amino acid position that corresponds to amino acid Gly 18 or amino acid Gly 39 of human wild-type epidermal growth factor is substituted with another amino acid, the polypeptide having epidermal growth factor receptor antagonist activity. 
     
     
         26 . The polypeptide variant of  claim 25 , wherein the epidermal growth factor receptor ligand is selected from the group consisting of: transforming growth factor-α (TGFα), betacellulin, heparin-binding EGF-like growth factor (HB-EGF), amphiregulin (AR) and epiregulin.