1. Vasculostatin inhibits intracranial glioma growth and negatively regulates in vivo angiogenesis through a CD36-dependent mechanism.
- Author
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Kaur B, Cork SM, Sandberg EM, Devi NS, Zhang Z, Klenotic PA, Febbraio M, Shim H, Mao H, Tucker-Burden C, Silverstein RL, Brat DJ, Olson JJ, and Van Meir EG
- Subjects
- Angiogenic Proteins genetics, Angiogenic Proteins metabolism, Animals, Brain Neoplasms genetics, Cell Line, Tumor, Cell Movement physiology, Corneal Neovascularization drug therapy, DNA, Complementary administration & dosage, DNA, Complementary genetics, Endothelial Cells pathology, Glioblastoma genetics, Humans, Mice, Mice, Nude, Neovascularization, Pathologic metabolism, Neovascularization, Pathologic therapy, Peptide Fragments genetics, Peptide Fragments metabolism, Rats, Receptors, G-Protein-Coupled, Transfection, Xenograft Model Antitumor Assays, Angiogenic Proteins biosynthesis, Brain Neoplasms blood supply, Brain Neoplasms therapy, CD36 Antigens metabolism, Glioblastoma blood supply, Glioblastoma therapy, Peptide Fragments biosynthesis
- Abstract
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.
- Published
- 2009
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