title: The role of perlecan and endorepellin in the control of tumor angiogenesis and endothelial cell autophagy.
abstract: During tumor growth and angiogenesis there is a dynamic remodeling of tissue architecture often accompanied by the release of extracellular matrix constituents full of biological activity. One of the key constituents of the tumor microenvironment is the large heparan sulfate proteoglycan perlecan. This proteoglycan, strategically located at cell surfaces and within basement membranes, is a well-defined pro-angiogenic molecule when intact. However, when partially processed by proteases released during cancer remodeling and invasion, the C-terminal fragment of perlecan, known as endorepellin, has opposite effects than its parent molecule. Endorepellin is a potent inhibitor of angiogenesis by exerting a dual receptor antagonism by simultaneously engaging VEGFR2 and α2β1 integrin. Signaling through the α2β1 integrin leads to actin disassembly and block of endothelial cell migration, necessary for capillary morphogenesis. Signaling through the VEGFR2 induces dephosphorylation of the receptor via activation of SHP-1 and suppression of downstream proangiogenic effectors, especially attenuating VEGFA expression. A novel and emerging role of endorepellin is its ability to evoke autophagy by activating Peg3 and various canonical autophagic markers. This effect is specific for endothelial cells as these are the primary cells expressing both VEGFR2 and α2β1 integrin. Thus, an endogenous fragment of a ubiquitous proteoglycan can regulate both angiogenesis and autophagy through a dual receptor antagonism. The biological properties of this natural endogenous protein place endorepellin as a potential therapeutic agent against cancer or diseases where angiogenesis is prominent.
authors.affiliation: a Department of Pathology , Anatomy and Cell Biology and the Cancer Cell Biology and Signalling Program, Kimmel Cancer Centre, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia , PA , USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Douglass
authors.affiliation: a Department of Pathology , Anatomy and Cell Biology and the Cancer Cell Biology and Signalling Program, Kimmel Cancer Centre, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia , PA , USA.
authors.forename: Atul
authors.initials: A
authors.lastname: Goyal
authors.affiliation: a Department of Pathology , Anatomy and Cell Biology and the Cancer Cell Biology and Signalling Program, Kimmel Cancer Centre, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia , PA , USA.
authors.forename: Renato V
authors.initials: RV
authors.lastname: Iozzo
mesh_terms: D000818:Animals; D001343:Autophagy / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D042783:Endothelial Cells / Q000166:cytology*; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D006801:Humans; D018919:Neovascularization, Physiologic / Q000502:physiology*
chemical_list: D019812:Heparan Sulfate Proteoglycans; C071927:perlecan
keywords: Angiogenesis; LG domains; Peg3; autophagy; perlecan