Proproteins and methods of use thereof

Abstract

A proprotein containing a functional protein coupled to a peptide mask that inhibits binding of the functional protein to its target or binding partner. An activatable proprotein contains a functional protein coupled to a peptide mask, and further coupled to an activatable linker, wherein in an non-activated state, the peptide mask inhibits binding of the functional protein to its target or binding partner and in an activated state the peptide mask does not inhibit binding of the functional protein to its target or binding partner. Proproteins can provide for reduced toxicity and adverse side effects that could otherwise result from binding of a functional protein at non-treatment sites if it were not inhibited from binding its binding partner. Proproteins can further provide improved biodistribution characteristics. Proproteins containing a peptide mask can display a longer in vivo or serum half-life than the corresponding functional protein not containing a peptide mask.

What is claimed is: 
     
         1 . A polypeptide comprising an interferon-alpha (IFN-α) and a peptide mask coupled to the IFN-α, wherein the peptide mask comprises an amino acid sequence having at least 90% homology to SEQ ID NO: 15. 
     
     
         2 . The polypeptide of  claim 1 , further comprising a linker between the IFN-α and the peptide mask. 
     
     
         3 . The polypeptide of  claim 2 , wherein the linker is a cleavable linker. 
     
     
         4 . The polypeptide of  claim 1 , wherein peptide mask comprises an amino acid sequence having at least 95% homology to SEQ ID NO: 15. 
     
     
         5 . The polypeptide of  claim 1 , further comprising at least one flexible linker positioned between the peptide mask and the IFN-α. 
     
     
         6 . The polypeptide of  claim 3 , further comprising at least one flexible linker positioned between the cleavable linker and the peptide mask. 
     
     
         7 . The polypeptide of  claim 3 , further comprising at least one flexible linker positioned between the cleavable linker and the IFN-α. 
     
     
         8 . The polypeptide of  claim 3 , further comprising a first flexible linker positioned between the IFN-α and the cleavable linker, and a second flexible linker positioned between the cleavable linker and the peptide mask. 
     
     
         9 . The polypeptide of  claim 8 , having an arrangement from N-terminus to C-terminus of:
 [peptide mask]-flexible linker L1-[cleavable linker]-flexible linker L2-[IFN-α]; or   [IFN-α]-flexible linker L1-[cleavable linker]-flexible linker L2-[peptide mask].   
     
     
         10 . A polynucleotide encoding the polypeptide of  claim 1 . 
     
     
         11 . A vector comprising the polynucleotide of  claim 10 . 
     
     
         12 . A host cell comprising the polynucleotide of  claim 10 . 
     
     
         13 . The host cell of  claim 12 , wherein the host cell is a bacterial cell. 
     
     
         14 . The host cell of  claim 12 , wherein the host cell is a mammalian cell. 
     
     
         15 . A composition comprising the polypeptide of  claim 1 . 
     
     
         16 . The composition of  claim 15 , which is a pharmaceutical composition comprising a therapeutically effective amount of the polypeptide and a pharmaceutically acceptable carrier. 
     
     
         17 . A method of treating a disease or disorder, comprising administering a therapeutically effective amount of the polypeptide of  claim 1  to a subject in need thereof. 
     
     
         18 . The method of  claim 17 , wherein the disease or disorder is cancer. 
     
     
         19 . A method of inhibiting angiogenesis in a mammalian subject in need thereof, comprising administering a therapeutically effective amount of the polypeptide of  claim 1  to the subject. 
     
     
         20 . A method of making a polypeptide comprising:
 (a) transforming a host cell with a vector comprising a polynucleotide encoding the polypeptide of  claim 1 ; and   (b) culturing the host cell transformed in (a) and expressing the polypeptide.