Methods and compositions for modulating angiogenesis and pericyte composition

Abstract

In certain aspects, the present disclosure relates to the insight that a polypeptide comprising a ligand-binding portion of the extracellular domain of activin-like kinase I (ALK1) polypeptide may be used to inhibit angiogenesis in vivo, particularly in mammals suffering angiogenesis-related disorders. Additionally, the disclosure demonstrates that inhibitors of ALK1 may be used to increase pericyte coverage in vascularized tissues, including tumors and the retina. The disclosure also identifies ligands for ALK1 and demonstrates that such ligands have pro-angiogenic activity, and describes antibodies that inhibit receptor-ligand interaction.

1 - 60 . (canceled) 
     
     
         61 . A method for treating pancreatic cancer in a mammal, the method comprising, administering to a mammal that has pancreatic cancer an effective amount of an agent selected from the group consisting of
 (a) an ALK1-ECD protein;   (b) an antibody that binds to an ALK1 ligand and inhibits the binding of the ALK1 ligand to ALK1, wherein the ALK1 ligand is selected from the group consisting of GDF5, GDF6, GDF7, BMP9 and BMP10; and   (c) an antibody that binds to an ALK1 polypeptide consisting of amino acids 22-118 of SEQ ID NO:1 and inhibits the binding of at least one ALK1 ligand selected from the group consisting of: GDF5, GDF6, GDF7, BMP9 and BMP10.   
     
     
         62 . The method of  claim 61 , wherein the ALK-1 ECD protein is an ALK1-Fc fusion protein. 
     
     
         63 . The method of  claim 62 , wherein the ALK1-Fc fusion protein comprises a polypeptide having an amino acid sequence that is at least 90% identical to the sequence of amino acids 22-118 of SEQ ID NO:1, which polypeptide is fused to an Fc portion of an immunoglobulin. 
     
     
         64 . The method of  claim 61 , wherein the ALK1-ECD protein binds to TGFβ-1 with a K D  of greater than 1×10 −6 . 
     
     
         65 . The method of  claim 61 , wherein the ALK1 ECD protein binds to one or more ALK1 ligands selected from the group consisting of: GDF5, GDF6, GDF7, BMP9 and BMP10. 
     
     
         66 . The method of  claim 61 , wherein the ALK1-ECD protein has a sequence of SEQ ID NO:3. 
     
     
         67 . The method of  claim 61 , wherein the ALK1 ECD protein comprises an amino acid sequence that is at least 90% identical to the sequence of amino acids corresponding to amino acids 34-95 of SEQ ID NO:1. 
     
     
         68 . The method of  claim 61 , wherein the ALK1 ECD comprises an amino acid sequence encoded by a nucleic acid that hybridized under stringent hybridization conditions to nucleotides 100-285 of SEQ ID NO:2 or a variant of nucleotides 100-285 of SEQ ID NO:2 that has the same coding sequence. 
     
     
         69 . The method of  claim 61 , wherein the antibody of (b) binds to the ALK1 polypeptide with a K D  of less than 5×10 −8  M. 
     
     
         70 . The method of  claim 61 , wherein the antibody of (b) binds to the ALK1 polypeptide with a K D  of less than 1×10 −10  M. 
     
     
         71 . The method of  claim 61 , wherein the antibody of (b) inhibits angiogenesis stimulated by at least one ALK1 ligand selected from the group consisting of: GDF5, GDF6 and GDF7. 
     
     
         72 . The method of  claim 61 , wherein the antibody of (b) inhibits binding of ALK1 to an ALK1 ligand, wherein the ALK1 ligand is selected from the group consisting of: BMP9 and BMP10. 
     
     
         73 . The method of  claim 61 , wherein the antibody of (c) inhibits angiogenesis stimulated by at least one ALK1 ligand selected from the group consisting of: GDF5, GDF6 and GDF7. 
     
     
         74 . The method of  claim 61 , wherein the antibody of (c) inhibits angiogenesis stimulated by at least one ALK1 ligand selected from the group consisting of: BMP9 and BMP10. 
     
     
         75 . The method of  claim 61 , wherein the agent is delivered intravenously. 
     
     
         76 . The method of  claim 61 , wherein the method further comprises administering a second agent that inhibits angiogenesis.