Elevated gadd153/chop expression during resveratrol-induced apoptosis in human colon cancer cells

Resveratrol (3,4′,5-tri-hydroxystilbene), a natural phytoalexin found at high levels in grapes and red wine, has been shown to induce anti-proliferation and apoptosis of human cancer cell lines. Resveratrol-induced dose-dependent apoptotic cell death in colon carcinoma cells, as measured by FACS analysis and internucleosomal DNA fragmentation assays. We demonstrate for the first time that resveratrol induce CCAAT/enhancer-binding protein-homologous protein (CHOP). Resveratrol-induced CHOP mRNA (and also protein) expression was inhibited by JNK specific inhibitor, but not ERK, p38 MAPK, PI3K and NF-κB inhibitors. Resveratrol-induced expression of CHOP involves the putative Sp1 site within the CHOP promoter region. Using a combination of the Sp1 cDNA transfection, the luciferase reporter assay and Sp1 inhibitor assay, we found that Sp1 site is required for resveratrol-mediated activation of the CHOP promoter. Suppression of CHOP expression by CHOP siRNA and treatment with mithramycin A attenuated resveratrol-induced apoptosis. Taken together, the present studies suggest that induction of CHOP protein may be involved, at least in part, in resveratrol-induced apoptosis.