Rapid insulin-like growth factor (IGF)-independent effects of IGF binding protein-3 on endothelial cell survival.
Angiogenic factors, such as vascular endothelial-derived growth factor (VEGF) and IGF-I, play pivotal roles in endothelial proliferation and migration. IGF binding protein-3 (IGFBP-3) is emerging as a key regulator of cell growth and apoptosis, both as an IGF antagonist and as an independent molecule. We investigated the role of IGFBP-3 in VEGFmediated survival of human macrovascular umbilical vein endothelial cells (HUVEC). Specific commercial ELISAs quantified cell proliferation and apoptosis, and Akt phosphorylation was assessed by immunoblots and confocal microscopy. IGF-I and VEGF significantly stimulated HUVEC proliferation and survival. Addition of IGFBP-3 reversed both IGF- and VEGF-induced proliferation and prevented the survival induced by these factors. The antiproliferative and proapoptotic effects of exogenous IGFBP-3 upon VEGF-induced HUVEC survival were not inhibited by blockade of the type 1 IGF receptor with alpha IR-3 immunoglobulin, which fully prevented IGF actions. An IGFBP-3 mutant, which binds IGFs normally but has a substituted mid-region domain, lost the ability to inhibit VEGF actions. VEGF-induced phosphorylation of Akt, as evident by both specific immunoblots and confocal microscopy, was significantly and rapidly reduced in the presence of IGFBP-3, as well as wortmannin.
Franklin
Sherry Lynn
SL
Division of Pediatric Endocrinology and Diabetes, Mattel Children's Hospital, University of California, Los Angeles, California 90095-1752, USA.
Ferry
Robert J
RJ
Cohen
Pinchas
P
D000906:Antibodies / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004347:Drug Interactions; D016228:Endothelial Growth Factors / Q000037:antagonists & inhibitors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology*; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000378:metabolism* / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D008222:Lymphokines / Q000037:antagonists & inhibitors / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors / Q000276:immunology; D014471:Umbilical Veins / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D000906:Antibodies; D016228:Endothelial Growth Factors; D018972:Insulin-Like Growth Factor Binding Protein 3; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D017526:Receptor, IGF Type 1; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C494918:AKT1 protein, human