Rapid insulin-like growth factor (IGF)-independent effects of IGF binding protein-3 on endothelial cell survival

J Clin Endocrinol Metab. 2003 Feb;88(2):900-7. doi: 10.1210/jc.2002-020472.

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

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies / pharmacology
  • Cell Division / drug effects
  • Cell Division / physiology
  • Cell Survival / drug effects
  • Cell Survival / physiology
  • Cells, Cultured
  • Drug Interactions
  • Endothelial Growth Factors / antagonists & inhibitors
  • Endothelial Growth Factors / pharmacology
  • Endothelium, Vascular / cytology*
  • Humans
  • Insulin-Like Growth Factor Binding Protein 3 / metabolism*
  • Insulin-Like Growth Factor Binding Protein 3 / pharmacology
  • Intercellular Signaling Peptides and Proteins / pharmacology
  • Lymphokines / antagonists & inhibitors
  • Lymphokines / pharmacology
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation / drug effects
  • Protein-Serine-Threonine Kinases*
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-akt
  • Receptor, IGF Type 1 / antagonists & inhibitors
  • Receptor, IGF Type 1 / immunology
  • Umbilical Veins / cytology
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factors

Substances

  • Antibodies
  • Endothelial Growth Factors
  • Insulin-Like Growth Factor Binding Protein 3
  • Intercellular Signaling Peptides and Proteins
  • Lymphokines
  • Proto-Oncogene Proteins
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factors
  • Phosphatidylinositol 3-Kinases
  • Receptor, IGF Type 1
  • AKT1 protein, human
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt