Growth factor complexes and modulation of cell migration and growth

Abstract

Isolated protein complexes are provided comprising growth factors such as IGF-I, IGF-II, VEGF or PDGF, or at least domains thereof that enable binding to and activation of both a growth factor receptor, and an integrin receptor-binding domain of vitronectin or fibronectin. These protein complexes may be in the form of oligo-protein complexes or single, synthetic proteins where the growth factor and vitronectin or fibronectin sequences are joined by a linker sequence. In particular forms, vitronectin or fibronectin sequences do not include a heparin binding domain and/or polyanionic domain. Also provided are uses of these protein complexes for stimulating or inducing cell migration and/or proliferation which may have use in wound healing, tissue engineering, cosmetic and therapeutic treatments such as skin replacement and skin replenishment and treatment of burns where epithelial cell migration is required. In other embodiments, the invention provides inhibition of cancer cell metastasis, particularly in relation to breast cancer.

1 . An isolated protein complex in the form of a synthetic chimeric protein comprising an amino acid sequence of:
 (i) a growth factor selected from IGF-I and IGF-II, or at least a domain of said growth factor which is capable of binding a cognate growth factor receptor; and   (ii) fibronectin (FN) or a fragment of FN comprising at least an integrin-binding domain of FN.   
     
     
         2 . The isolated protein complex of  claim 1 , wherein the integrin-binding domain is an α 1  integrin-binding domain or an α 4  integrin-binding domain. 
     
     
         3 . The isolated protein complex of  claim 1 , wherein the fragment of FN comprises amino acids 1299-1572 of a mature FN sequence (SEQ ID NO:25). 
     
     
         4 . The isolated protein complex of  claim 1 , wherein the fragment of FN comprises amino acids 1479-1572 of a mature FN sequence (SEQ ID NO:25). 
     
     
         5 . The isolated protein complex of  claim 1 , which does not comprise an IGFBP amino acid sequence. 
     
     
         6 . The isolated protein complex of  claim 1 , wherein and said at least a domain of IGF-I which is capable of binding a cognate growth factor receptor includes residue 24 of IGF-I. 
     
     
         7 . The isolated protein complex of  claim 1 , comprising amino acid residues 4 to 70 of IGF-I. 
     
     
         8 . The isolated protein complex of  claim 1 , comprising amino acid residues 1 to 70 of IGF-I. 
     
     
         9 . The isolated protein complex of  claim 1 , further comprising at least one linker sequence. 
     
     
         10 . The isolated protein complex of  claim 9 , wherein the linker sequence comprises a protease cleavage site. 
     
     
         11 . The isolated protein complex of  claim 9 , wherein the linker sequence is selected from the group consisting of: 
       
         
           
                 
                 
                 
               
                   (i) 
                   Gly 4  Ser; 
                   (SEQ ID NO: 4) 
                 
                     
                 
                   (ii) 
                   Gly 4  Ser 3 ; 
                   (SEQ ID NO: 5) 
                 
                     
                 
                   (iii) 
                   (Gly 4  Ser) 3 .; 
                   (SEQ ID NO: 6) 
                 
                     
                 
                   (iv) 
                   Leu Ile Lys Met Lys Pro; 
                   (SEQ ID NO: 7) 
                 
                   and 
                 
                     
                 
                   (v) 
                   Gln Pro Gln Gly Leu Ala Lys. 
                   (SEQ ID NO: 8) 
                 
             
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         12 . An isolated nucleic acid encoding the isolated protein complex of  claim 1 . 
     
     
         13 . A genetic construct comprising the isolated nucleic acid of  claim 12  operably linked to one or more regulatory nucleotide sequences in a vector. 
     
     
         14 . The genetic construct of  claim 13 , which is an expression construct wherein the isolated nucleic acid is operably linked to a promoter. 
     
     
         15 . A host cell comprising the genetic construct of  claim 13 . 
     
     
         16 . A pharmaceutical composition comprising the isolated protein complex of the  claim 1  and a pharmaceutically-acceptable carrier, diluent or excipient. 
     
     
         17 . A surgical implant, scaffold or prosthesis impregnated, coated or otherwise comprising the isolated protein complex of  claim 1 . 
     
     
         18 . A wound or burn dressing comprising the isolated protein complex of  claim 1 . 
     
     
         19 . A pharmaceutical composition comprising the isolated protein complex of  claim 1  and a pharmaceutically-acceptable carrier, diluent or excipient. 
     
     
         20 . A method of promoting cell migration and/or proliferation including the step of using the isolated protein complex of  claim 1  to bind both a growth factor receptor and an integrin receptor expressed by a cell to thereby induce, augment or otherwise promote migration and/or proliferation of said cell. 
     
     
         21 . The method of  claim 20  wherein the isolated protein complex is administered to an animal to promote cell migration and/or proliferation in situ. 
     
     
         22 . The method of  claim 21 , for prophylactically or therapeutically to induce, augment or otherwise promote epithelial cell migration and/or proliferation to thereby facilitate wound healing in situ. 
     
     
         23 . The method of  claim 22 , wherein the animal is a human. 
     
     
         24 . The method of  claim 20 , wherein the isolated protein complex is administered to one or more cells or tissues in vitro.