Peroxisome Proliferator-activated Receptor γ Ligands Are Potent Inhibitors of Angiogenesis in Vitro and in Vivo

doi:10.1074/jbc.274.13.9116

Peroxisome Proliferator-activated Receptor γ Ligands Are Potent Inhibitors of Angiogenesis in Vitro and *in Vivo**

From the Department of Cardiovascular Research, Genentech, Inc., South San Francisco, California 94080

Abstract

Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor that functions as a transcription factor to mediate ligand-dependent transcriptional regulation. Activation of PPARγ by the naturally occurring ligand, 15-deoxy-Δ12,14-prostaglandin J₂(15d-PGJ₂), or members of a new class of oral antidiabetic agents, e.g. BRL49653 and ciglitizone, has been linked to adipocyte differentiation, regulation of glucose homeostasis, inhibition of macrophage and monocyte activation, and inhibition of tumor cell proliferation. Here we report that human umbilical vein endothelial cells (HUVEC) express PPARγ mRNA and protein. Activation of PPARγ by the specific ligands 15d-PGJ₂, BRL49653, or ciglitizone, dose dependently suppresses HUVEC differentiation into tube-like structures in three-dimensional collagen gels. In contrast, specific PPARα and -β ligands do not affect tube formation although mRNA for these receptors are expressed in HUVEC. PPARγ ligands also inhibit the proliferative response of HUVEC to exogenous growth factors. Treatment of HUVEC with 15d-PGJ₂also reduced mRNA levels of vascular endothelial cell growth factor receptors 1 (Flt-1) and 2 (Flk/KDR) and urokinase plasminogen activator and increased plasminogen activator inhibitor-1 (PAI-1) mRNA. Finally, administration of 15d-PGJ₂ inhibited vascular endothelial cell growth factor-induced angiogenesis in the rat cornea. These observations demonstrate that PPARγ ligands are potent inhibitors of angiogenesis in vitro and in vivo, and suggest that PPARγ may be an important molecular target for the development of small-molecule inhibitors of angiogenesis.

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, MS 42, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080. Tel.: 650-225-6870; Fax: 650-225-6327; E-mail:meg{at}gene.com.
Abbreviations:

PPARs

peroxisome proliferator-activated receptors

HUVEC

human umbilical vein endothelial cells

15d-PGJ₂

15-deoxy-Δ12,14-prostaglandin J₂

RXR

retinoid acid receptor

VEGF

vascular endothelial growth factor

PMA

phorbol myristate acetate

RT-PCR

reverse transcription-polymerase chain reaction

GAPDH

glyceraldehyde-3-phosphate dehydrogenase

BrdUrd

5′-bromo-2′-deoxyuridine

FBS

fetal bovine serum

bFGF

basic fibroblast growth factor

ITS

insulin, transferrin, and selenium A

uPA

urokinase-type plasminogen activator
- Received November 25, 1998.
- Revision received January 6, 1999.
The American Society for Biochemistry and Molecular Biology, Inc.