Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Antibodies / pharmacology
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Cell Division / drug effects
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Cell Division / physiology
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Cell Survival / drug effects
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Cell Survival / physiology
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Cells, Cultured
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Drug Interactions
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Endothelial Growth Factors / antagonists & inhibitors
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Endothelial Growth Factors / pharmacology
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Endothelium, Vascular / cytology*
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Humans
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Insulin-Like Growth Factor Binding Protein 3 / metabolism*
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Insulin-Like Growth Factor Binding Protein 3 / pharmacology
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Intercellular Signaling Peptides and Proteins / pharmacology
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Lymphokines / antagonists & inhibitors
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Lymphokines / pharmacology
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Phosphatidylinositol 3-Kinases / metabolism
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Phosphorylation / drug effects
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Protein Serine-Threonine Kinases*
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-akt
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Receptor, IGF Type 1 / antagonists & inhibitors
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Receptor, IGF Type 1 / immunology
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Umbilical Veins / cytology
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Vascular Endothelial Growth Factor A
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Vascular Endothelial Growth Factors
Substances
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Antibodies
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Endothelial Growth Factors
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Insulin-Like Growth Factor Binding Protein 3
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Intercellular Signaling Peptides and Proteins
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Lymphokines
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Proto-Oncogene Proteins
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Vascular Endothelial Growth Factor A
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Vascular Endothelial Growth Factors
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Receptor, IGF Type 1
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AKT1 protein, human
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-akt