title: Inhibition of angiogenesis by a tenascin-c peptide which is capable of activating beta1-integrins.
abstract: In addition to humoral angiogenic factors, including vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), integrin-mediated adhesion of vascular endothelial cells to the extracellular matrix plays an important role in neovascularization. We recently found that TNIIIA2, a peptide derived from tenascin-C, induces functional activation of beta1 integrins. Here we investigated the effect of TNIIIA2 on vascular endothelial cell migration and proliferation, key processes for angiogenesis. TNIIIA2 was shown to activate beta1-integrins on human dermal microvascular endothelial cells (HDMEC). HDMEC adhered to fibronectin mainly via integrin alpha5beta1 and their haptotactic migration on that substrate was inhibited by TNIIIA2, in concomitant with a marked inhibition of Rac activation. TNIIIA2-treatment unaffected autophosphorylation of focal adhesion kinase (FAK), but induced its physical association with phospho-paxillin (Tyr118), suggesting the FAK/paxillin-dependent negative regulation of Rac activation. HDMEC proliferation on the fibronectin substrate was also inhibited by TNIIIA2-treatment, and this was accompanied either by an increase in the population of G 0/G1 cells and, conversely, a decrease in the population of S and G2/M cells or by dephosphorylation/inactivation of MAP-kinase (ERK1/2). Inhibited HDMEC migration and proliferation were both restored by pretreating the cells with a fibronectin peptide, FNIII14, which is capable of inactivating beta1-integrins. The chorioallantoic membrane assay demonstrated an antiangiogenic effect of TNIIIA2 in vivo. Thus, TNIIIA2 appears to negatively regulate angiogenesis by inhibiting migration and proliferation of endothelial cells. The ability to activate beta1-integrins may be responsible for the antiangiogenic effect of TNIIIA2, although it cannot be excluded the possibility that an additional mechanism(s) may play a role.
authors.affiliation: Department of Molecular Patho-Physiology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Saito
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shiota
authors.forename: Mayuu
authors.initials: M
authors.lastname: Nishisaka
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Owaki
authors.forename: Mariko
authors.initials: M
authors.lastname: Shimamura
authors.forename: Fumio
authors.initials: F
authors.lastname: Fukai
mesh_terms: D020533:Angiogenesis Inhibitors; D000818:Animals; D001711:Biotransformation / Q000187:drug effects; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000187:drug effects; D042783:Endothelial Cells / Q000187:drug effects; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D047468:Immunoprecipitation; D019012:Integrin beta1 / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000096:biosynthesis; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D019063:Tenascin / Q000494:pharmacology*; D014947:Wounds and Injuries / Q000473:pathology; D020744:rac GTP-Binding Proteins / Q000096:biosynthesis; D020741:rho GTP-Binding Proteins / Q000378:metabolism
chemical_list: D020533:Angiogenesis Inhibitors; D019012:Integrin beta1; D019063:Tenascin; D020928:Mitogen-Activated Protein Kinases; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins