title: VEGF and inhibitors of TGFbeta type-I receptor kinase synergistically promote blood-vessel formation by inducing alpha5-integrin expression.
abstract: Vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGFbeta) are potent regulators of angiogenesis. How VEGF and TGFbeta signaling pathways crosstalk is not well understood. Therefore, we analyzed the effects of the TGFbeta type-I-receptor inhibitors (SB-431542 and LY-2157299) and VEGF on endothelial cell (EC) function and angiogenesis. We show that SB-431542 dramatically enhances VEGF-induced formation of EC sheets from fetal mouse metatarsals. Sub-optimal doses of VEGF and SB-431542 synergistically induced EC migration and sprouting of EC spheroids, whereas overexpression of a constitutively active form of TGFbeta type-I receptor had opposite effects. Using quantitative PCR, we demonstrated that VEGF and SB-431542 synergistically upregulated the mRNA expression of genes involved in angiogenesis, including the integrins alpha5 and beta3. Specific downregulation of alpha5-integrin expression or functional blocking of alpha5 integrin with a specific neutralizing antibody inhibited the cooperative effect of VEGF and SB-431542 on EC sprouting. In vivo, LY-2157299 induced angiogenesis and enhanced VEGF- and basic-fibroblast-growth-factor-induced angiogenesis in a Matrigel-plug assay, whereas adding an alpha5-integrin-neutralizing antibody to the Matrigel selectively inhibited this enhanced response. Thus, induction of alpha5-integrin expression is a key determinant by which inhibitors of TGFbeta type-I receptor kinase and VEGF synergistically promote angiogenesis.
authors.affiliation: Department of Molecular Cell Biology and Centre for Biomedical Genetics, Leiden University Medical Center, The Netherlands.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liu
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Maarten
authors.initials: M
authors.lastname: van Dinther
authors.forename: Sandra H
authors.initials: SH
authors.lastname: van Heiningen
authors.forename: Gudrun
authors.initials: G
authors.lastname: Valdimarsdottir
authors.forename: Theo
authors.initials: T
authors.lastname: van Laar
authors.forename: Marion
authors.initials: M
authors.lastname: Scharpfenecker
authors.forename: Clemens W G M
authors.initials: CW
authors.lastname: Löwik
authors.forename: Marie-José
authors.initials: MJ
authors.lastname: Goumans
authors.forename: Peter
authors.initials: P
authors.lastname: Ten Dijke
authors.forename: Evangelia
authors.initials: E
authors.lastname: Pardali
mesh_terms: D000818:Animals; D001549:Benzamides; D001681:Biological Assay; D002465:Cell Movement / Q000187:drug effects; D003094:Collagen / Q000378:metabolism; D004149:Dioxoles; D004338:Drug Combinations; D004357:Drug Synergism; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005333:Fetus / Q000098:blood supply / Q000187:drug effects; D020869:Gene Expression Profiling; D006801:Humans; D039482:Integrin alpha5 / Q000378:metabolism*; D039661:Integrin beta3 / Q000378:metabolism; D007797:Laminin / Q000378:metabolism; D051379:Mice; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D009500:Neutralization Tests; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D011509:Proteoglycans / Q000378:metabolism; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors*; D018874:Spheroids, Cellular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*
chemical_list: C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; D004149:Dioxoles; D004338:Drug Combinations; D039482:Integrin alpha5; D039661:Integrin beta3; D007797:Laminin; D047428:Protein Kinase Inhibitors; D011509:Proteoglycans; D018125:Receptors, Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; C059485:matrigel; D003094:Collagen; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I