Vascular Endothelial Growth Factor Increases Urokinase Receptor Expression in Vascular Endothelial Cells

doi:10.1074/jbc.270.17.9709

Vascular Endothelial Growth Factor Increases Urokinase Receptor Expression in Vascular Endothelial Cells (*)

From the (1) Department of Morphology, University Medical Center, 1211 Geneva 4, Switzerland, Dipartimento di Genetica e Microbiologia, Universit di Pavia, 27100 Pavia, Italy, the
(2) Department of Cardiovascular Research, Genentech Inc., South San Francisco, California 94080, and the
(3) Heart and Stroke Foundation of Canada, Ottawa, Ontario K1N9M2, Canada

** To whom correspondence should be addressed:
Dept. of Morphology, University Medical Center, 1 rue Michel Servet, 1211 Geneva 4, Switzerland.
Tel.: 22-702-52-91; Fax: 22-347-33-34.

Abstract

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor and endothelial cell-specific mitogen that stimulates urokinase-type plasminogen activator (uPA) activity in vascular endothelial cells. Here, we report that VEGF increases the high affinity binding of uPA to the same cells and that this binding is prevented by a peptide corresponding to the uPA receptor (uPAR) binding growth factor-like domain of uPA. Ligand cross-linking, ligand blotting, and uPA-Sepharose affinity chromatography revealed an increase in a cell surface uPA binding protein that corresponds to the uPAR on the basis of its affinity for uPA, M_rof 50,000-55,000, and phosphatidylinositol-specific phospholipase C sensitivity. By Scatchard analysis, VEGF increased the number of uPAR molecules by 2.8-3.5-fold and concomitantly decreased their affinity for uPA. By northern blotting uPAR mRNA was increased in a dose- and time-dependent manner in response to VEGF. Taken together, these findings demonstrate that VEGF-induced angiogenesis is accompanied by increased uPAR expression and uPA activity on the endothelial cell surface. These observations are consistent with the notion that the uPA-uPAR interaction facilitates cellular invasion.

Footnotes

↵^§ Contributed equally to this paper.
↵^¶ Supported by a fellowship from AIRC.
↵* Supported by grants from the Swiss National Science Foundation (31-34088.92, 31-34097.92, and 31-39717.93), from the Italian Association for Cancer Research (AIRC), and from the Italian Ministry of Technological and Scientific Research. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

bFGF

basic fibroblast growth factor

VEGF

vascular endothelial growth factor

ECM

extracellular matrix

BME

bovine microvascular endothelial

BAE

bovine aortic endothelial

uPA

urokinase-type plasminogen activator

uPAR

uPA receptor

tPA

tissue-type plasminogen activator

scuPA

single-chain uPA

tcuPA

two-chain uPA

PAI

PA inhibitors

HUVE

human umbilical vein endothelial

BLE

bovine lymphatic endothelial

PI-PLC

phosphatidylinositol-specific phospholipase C

DMEM

Dulbecco's modified Eagle's medium.