Vasculostatin inhibits intracranial glioma growth and negatively regulates in vivo angiogenesis through a CD36-dependent mechanism.
Angiogenesis is a critical physiologic process that is appropriated during tumorigenesis. Little is known about how this process is specifically regulated in the brain. Brain angiogenesis inhibitor-1 (BAI1) is a brain-predominant seven-transmembrane protein that contains five antiangiogenic thrombospondin type-1 repeats (TSR). We recently showed that BAI1 is cleaved at a conserved proteolytic cleavage site releasing a soluble, 120 kDa antiangiogenic factor called vasculostatin (Vstat120). Vstat120 has been shown to inhibit in vitro angiogenesis and suppress subcutaneous tumor growth. Here, we examine its effect on the intracranial growth of malignant gliomas and further study its antitumor mechanism. First, we show that expression of Vstat120 strongly suppresses the intracranial growth of malignant gliomas, even in the presence of the strong proangiogenic stimulus mediated by the oncoprotein epidermal growth factor receptor variant III (EGFRvIII). This tumor-suppressive effect is accompanied by a decrease in tumor vascular density, suggesting a potent antiangiogenic effect in the brain. Second, and consistent with this interpretation, we find that treatment with Vstat120 reduces the migration of cultured microvascular endothelial cells in vitro and inhibits corneal angiogenesis in vivo. Third, we show that these antivascular effects critically depend on the presence of the cell surface receptor CD36 on endothelial cells in vitro and in vivo, supporting the role of Vstat120 TSRs in mediating these effects. These results advance the understanding of brain-specific angiogenic regulation, and suggest that Vstat120 has therapeutic potential in the treatment of brain tumors and other intracerebral vasculopathies.
Kaur
Balveen
B
Department of Neurosurgery, Laboratory of Molecular Neuro-Oncology, Winship Cancer Institute, Emory University, School of Medicine, Atlanta, Georgia 30322, USA.
Cork
Sarah M
SM
Sandberg
Eric M
EM
Devi
Narra S
NS
Zhang
Zhaobin
Z
Klenotic
Philip A
PA
Febbraio
Maria
M
Shim
Hyunsuk
H
Mao
Hui
H
Tucker-Burden
Carol
C
Silverstein
Roy L
RL
Brat
Daniel J
DJ
Olson
Jeffrey J
JJ
Van Meir
Erwin G
EG
D042501:Angiogenic Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001932:Brain Neoplasms / Q000098:blood supply* / Q000235:genetics / Q000628:therapy*; D018955:CD36 Antigens / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D016510:Corneal Neovascularization / Q000188:drug therapy; D018076:DNA, Complementary / Q000008:administration & dosage / Q000235:genetics; D042783:Endothelial Cells / Q000473:pathology; D005909:Glioblastoma / Q000098:blood supply* / Q000235:genetics / Q000628:therapy*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000378:metabolism / Q000628:therapy; D010446:Peptide Fragments / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D051381:Rats; D043562:Receptors, G-Protein-Coupled; D014162:Transfection; D023041:Xenograft Model Antitumor Assays
C468226:ADGRB1 protein, human; D042501:Angiogenic Proteins; D018955:CD36 Antigens; D018076:DNA, Complementary; D010446:Peptide Fragments; D043562:Receptors, G-Protein-Coupled