Transforming growth factor beta1 (TGF-beta1) promotes endothelial cell survival during in vitro angiogenesis via an autocrine mechanism implicating TGF-alpha signaling.
Mouse capillary endothelial cells (1G11 cell line) embedded in type I collagen gels undergo in vitro angiogenesis. Cells rapidly reorganize and form capillary-like structures when stimulated with serum. Transforming growth factor beta1 (TGF-beta1) alone can substitute for serum and induce cell survival and tubular network formation. This TGF-beta1-mediated angiogenic activity depends on phosphatidylinositol 3-kinase (PI3K) and p42/p44 mitogen-activated protein kinase (MAPK) signaling. We showed that specific inhibitors of either pathway (wortmannin, LY-294002, and PD-98059) all suppressed TGF-beta1-induced angiogenesis mainly by compromising cell survival. We established that TGF-beta1 stimulated the expression of TGF-alpha mRNA and protein, the tyrosine phosphorylation of a 170-kDa membrane protein representing the epidermal growth factor (EGF) receptor, and the delayed activation of PI3K/Akt and p42/p44 MAPK. Moreover, we showed that all these TGF-beta1-mediated signaling events, including tubular network formation, were suppressed by incubating TGF-beta1-stimulated endothelial cells with a soluble form of an EGF receptor (ErbB-1) or tyrphostin AG1478, a specific blocker of EGF receptor tyrosine kinase. Finally, addition of TGF-alpha alone poorly stimulated angiogenesis; however, by reducing cell death, it strongly potentiated the action of TGF-beta1. We therefore propose that TGF-beta1 promotes angiogenesis at least in part via the autocrine secretion of TGF-alpha, a cell survival growth factor, activating PI3K/Akt and p42/p44 MAPK.
Viñals
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Institute of Signaling, Developmental Biology and Cancer Research, CNRS UMR 6543-Centre Antoine Lacassagne, 06189 Nice Cedex 2, France.
Pouysségur
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D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D016923:Cell Death; D002460:Cell Line; D002470:Cell Survival; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D024042:Collagen Type I / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D018919:Neovascularization, Physiologic; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D011799:Quinazolines; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D016211:Transforming Growth Factor alpha / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D053773:Transforming Growth Factor beta1; D020032:Tyrphostins / Q000494:pharmacology; D000077191:Wortmannin
D000730:Androstadienes; D002867:Chromones; D024042:Collagen Type I; D004791:Enzyme Inhibitors; D005419:Flavonoids; D009025:Morpholines; D011799:Quinazolines; D012333:RNA, Messenger; C508960:TGFB1 protein, human; C508961:Tgfb1 protein, mouse; D016211:Transforming Growth Factor alpha; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D020032:Tyrphostins; C101044:RTKI cpd; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin