Regulation of apoptosis by resveratrol through JAK/STAT and mitochondria mediated pathway in human epidermoid carcinoma A431 cells

Resveratrol (trans-3,4',5-trihydroxystilbene), a polyphenolic phytoalexin present mainly in grapes, red wine and berries, is known to possess strong chemopreventive and anticancer properties. Here, we demonstrated the anti-proliferative and apoptosis-inducing activities of resveratrol in human epidermoid carcinoma A431 cells. Resveratrol has cytotoxic effects through inhibiting cellular proliferation of A431 cells, which leads to the induction of apoptosis, as evident by an increase in the fraction of cells in the SUb-G(I) phase of the cell cycle and Annexin-V binding of externalized phosphatidylserine. Results revealed that inhibition of proliferation is associated with regulation of the JAK/STAT pathway, where resveratrol prevents phosphorylation of JAK, thereby inhibiting STAT1 phosphorylation. Furthermore, resveratrol treatment actively stimulated reactive oxygen species (ROS) and mitochondrial membrane depolarization. Consequently, an imbalance in the Bax/Bcl-2 ratio triggered the caspase cascade and subsequent cleavage of PARP, thereby shifting the balance in favor of apoptosis. These observations indicate that resveratrol treatment inhibits JAK/STAT-mediated gene transcription and induce the mitochondrial cell death pathway. (C) 2008 Elsevier Inc. All rights reserved.