Resveratrol at anti-angiogenesis/anticancer concentrations suppresses protein kinase G signaling and decreases IAPs expression in HUVECs.

BACKGROUND Resveratrol increases nitric oxide (NO) production via increased expression and activation of endothelial-form-NO-synthase (eNOS) in endothelial cells. However, the role of downstream cGMP/protein kinase G (PKG) signaling, a pathway activated by NO/eNOS, in pro- and anti-angiogenic effects of resveratrol is still unclear. MATERIALS AND METHODS Endogenous NO/cGMP/PKG pathway and downstream cell-survival proteins (Inhibitor of Apoptosis Proteins, IAPs) were studied in relation to pro- and anti-angiogenic effects of resveratrol in human umbilical vein endothelial cells (HUVECs). RESULTS Resveratrol at higher/anti-angiogenic concentrations inhibits HUVEC tube formation and cell migration/invasion (indices of angiogenesis). Resveratrol at lower concentrations stimulates proliferation and protects HUVECs against spontaneous apoptosis. 8-Br-cGMP, a direct activator of PKG, protects against pro-apoptotic effects of high-concentration resveratrol. Western blot analyses showed that anti-angiogenic concentrations of resveratrol suppress endogenous PKG kinase activity and decrease the expression of four cell-survival proteins, c-IAP1, c-IAP2, livin and XIAP. CONCLUSION Resveratrol-induced anti-angiogenesis/pro-apoptosis induced suppression of PKG signaling and decreased expression of the cell-survival proteins c-IAP1, c-IAP2, livin and XIAP.