INHIBITION OF ANGIOGENESIS BY THROMBOSPONDIN-2

To assess the ability of proteins of the thrombospondin family to inhi bit angiogenesis, recombinant murine thrombospondin-2, bovine thrombos pondin-2/CISP and thrombospondin-5/COMP were purified and tested for a bility to block the migration of capillary endothelial cells towards a variety of inducers and to inhibit neovascularization induced in the rat cornea. Both preparations of thrombospondin-2 were active inhibito rs in vitro and in vivo whereas thrombospondin-5/COMP was inactive. Th ese results define thrombospondin-2 as a newly identified naturally oc curring inhibitor of angiogenesis and suggest that the properdin-like type 1 modules that it shares with antiangiogenic thrombospondin-l and are missing in thrombospondin-5/COMP could contribute to this activit y. (C) 1995 Academic Press,Inc.