Vascular Endothelial Growth Factor Regulates Endothelial Cell Survival through the Phosphatidylinositol 3′-Kinase/Akt Signal Transduction Pathway

doi:10.1074/jbc.273.46.30336

Vascular Endothelial Growth Factor Regulates Endothelial Cell Survival through the Phosphatidylinositol 3′-Kinase/Akt Signal Transduction Pathway

REQUIREMENT FOR Flk-1/KDR ACTIVATION*

From the Departments of ^‡Cardiovascular Research and ^§Molecular Oncology, Genentech, Inc., South San Francisco, California 94080

Abstract

Vascular endothelial growth factor (VEGF) has been found to have various functions on endothelial cells, the most prominent of which is the induction of proliferation and differentiation. In this report we demonstrate that VEGF or a mutant, selectively binding to the Flk-1/KDR receptor, displayed high levels of survival activity, whereas Flt-1-specific ligands failed to promote survival of serum-starved primary human endothelial cells. This activity was blocked by the phosphatidylinositol 3′-kinase (PI3-kinase)-specific inhibitors wortmannin and LY294002. Endothelial cells cultured in the presence of VEGF and the Flk-1/KDR-selective VEGF mutant induced phosphorylation of the serine-threonine kinase Akt in a PI3-kinase-dependent manner. Akt activation was not detected in response to stimulation with placenta growth factor or an Flt-1-selective VEGF mutant. Furthermore, a constitutively active Akt was sufficient to promote survival of serum-starved endothelial cells in transient transfection experiments. In contrast, overexpression of a dominant-negative form of Akt blocked the survival effect of VEGF. These findings identify the Flk-1/KDR receptor and the PI3-kinase/Akt signal transduction pathway as crucial elements in the processes leading to endothelial cell survival induced by VEGF. Inhibition of apoptosis may represent a major aspect of the regulatory activity of VEGF on the vascular endothelium.

Footnotes

↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¶ To whom correspondence should be addressed: Dept. of Cardiovascular Research, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080. Tel.: 650-225-2968; Fax: 650-225-6327.
Abbreviations:

HUVE

human umbilical vein endothelial

PI3-kinase

phosphatidylinositol 3′-kinase

VEGF

vascular endothelial growth factor

rh

recombinant human

PlGF

placenta growth factor

PBS

phosphate-buffered saline

PI

propidium iodide

bFGF

basic fibroblast growth factor

sel

selective

KDR

kinase domain region.
- Received March 26, 1998.
- Revision received July 28, 1998.
The American Society for Biochemistry and Molecular Biology, Inc.