trans- 3,4,5′-Trihydroxystibene Inhibits Hypoxia-Inducible Factor 1α and Vascular Endothelial Growth Factor Expression in Human Ovarian Cancer Cells

Abstract

trans-3,4,5′-Trihydroxystibene (resveratrol) is a natural product commonly found in the human diet and has been shown recently to have anticancer effects on various human cancer cells. However, the molecular basis for its anticancer action remains to be elucidated. In this study, we investigated the effect of resveratrol on hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) expression in human ovarian cancer cells A2780/CP70 and OVCAR-3. We found that although resveratrol did not affect HIF-1α mRNA levels, it did dramatically inhibit both basal-level and growth factor-induced HIF-1α protein expression in the cells. Resveratrol also greatly inhibited VEGF expression. Mechanistically, we demonstrated that resveratrol inhibited HIF-1α and VEGF expression through multiple mechanisms. First, resveratrol inhibited AKT and mitogen-activated protein kinase activation, which played a partial role in the down-regulation of HIF-1α expression. Second, resveratrol inhibited insulin-like growth factor 1-induced HIF-1α expression through the inhibition of protein translational regulators, including M_r 70,000 ribosomal protein S6 kinase 1, S6 ribosomal protein, eukaryotic initiation factor 4E-binding protein 1, and eukaryotic initiation factor 4E. Finally, we showed that resveratrol substantially induced HIF-1α protein degradation through the proteasome pathway. Our data suggested that resveratrol may inhibit human ovarian cancer progression and angiogenesis by inhibiting HIF-1α and VEGF expression and thus provide a novel potential mechanism for the anticancer action of resveratrol.