title: Insulin-like growth factor binding protein-3 induces angiogenesis through IGF-I- and SphK1-dependent mechanisms.
abstract: Angiogenesis is critical for development and repair, and is a prominent feature of many pathological conditions. Based on evidence that insulin-like growth factor binding protein (IGFBP)-3 enhances cell motility and activates sphingosine kinase (SphK) in human endothelial cells, we have investigated whether IGFBP-3 plays a role in promoting angiogenesis. IGFBP-3 potently induced network formation by human endothelial cells on Matrigel. Moreover, it up-regulated proangiogenic genes, such as vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP)-2 and -9. IGFBP-3 even induced membrane-type 1 MMP (MT1-MMP), which regulates MMP-2 activation. Decreasing SphK1 expression by small interfering RNA (siRNA), blocked IGFBP-3-induced network formation and inhibited VEGF, MT1-MMP but not IGF-I up-regulation. IGF-I activated SphK, leading to sphingosine-1-phosphate (S1P) formation. The IGF-I effect on SphK activity was blocked by specific inhibitors of IGF-IR, PI3K/Akt and ERK1/2 phosphorylation. The disruption of IGF-I signaling prevented the IGFBP-3 effect on tube formation, SphK activity and VEGF release. Blocking ERK1/2 signaling caused the loss of SphK activation and VEGF and IGF-I up-regulation. Finally, IGFBP-3 dose-dependently stimulated neovessel formation into subcutaneous implants of Matrigel in vivo. Thus, IGFBP-3 positively regulates angiogenesis through involvement of IGF-IR signaling and subsequent SphK/S1P activation.
authors: Laboratory of Molecular and Cellular Endocrinology, Department of Internal Medicine, University of Turin, Turin, Italy. riccarda.granata@unito.it
authors: R
authors: R
authors: Granata
authors: L
authors: L
authors: Trovato
authors: E
authors: E
authors: Lupia
authors: G
authors: G
authors: Sala
authors: F
authors: F
authors: Settanni
authors: G
authors: G
authors: Camussi
authors: R
authors: R
authors: Ghidoni
authors: E
authors: E
authors: Ghigo
mesh_terms: D000818:Animals; D002196:Capillaries / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D004338:Drug Combinations; D004730:Endothelium, Vascular / Q000166:cytology*; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000378:metabolism / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D007797:Laminin / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009389:Neovascularization, Pathologic; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism / Q000502:physiology*; D011509:Proteoglycans / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000378:metabolism; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D000099157:Sphingosine Kinase
chemical_list: D003094:Collagen; D004338:Drug Combinations; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D007797:Laminin; D017853:Phosphotransferases (Alcohol Group Acceptor); D011509:Proteoglycans; D017526:Receptor, IGF Type 1; D042461:Vascular Endothelial Growth Factor A; D000099157:Sphingosine Kinase; C059485:matrigel