Effects of a natural polyphenol on nicotine-induced pancreatic cancer cell proliferation

INTRODUCTION: Resveratrol (trans-3, 4’, 5-trihydroxystilbene), a phytoalexin derived from the skin of grapes and other fruits, has anti-inflammatory and anti-oxidant effects. Its anti-carcinogenic effects are closely associated with its antioxidant activity; thus, the use of resveratrol as a possible cancer chemo-preventive is considered to be an important area of investigation. In this study we have examined the inhibitory effects of resveratrol in nicotine induced proliferation of pancreatic cancer cells. METHODS: Cultured AR42J cells were incubated with 100 μM nicotine for 3 min and with 100 μM resveratrol for 30 min, either alone or in combination. Proliferation assays were conducted for a period of 0 to 96 h in serum media, incubated with nicotine and resveratrol, and evaluated by MTT assay. Protein was measured in lysed cells and activation of MAPK signals was measured by western blot using purified p-ERK antibody. Co-localization of activated ERK signals was confirmed by FITC conjugated ERK antibody using immunofluorescence assay and confocal microscopy. Biomarker of lipid peroxidation was determined in cell lysates by malondialdehyde (MDA) bioassay. RESULTS: Resveratrol significantly suppressed the nicotine-induced proliferation of acinar cells compared to untreated controls (p<0.05). Mitogen activated protein kinase (MAPK) analysis revealed up-regulation of p-ERK expression by nicotine (p<0.05) that was suppressed significantly by resveratrol (p<0.05). Co-localization of activated ERK signals was confirmed by FITC conjugated ERK antibody, and this response was reduced significantly by resveratrol. Nicotine-induced malondialdehyde formation was also suppressed by resveratrol (p<0.05). CONCLUSIONS: The data suggest that resveratrol suppressed nicotine-induced AR42J cell proliferation. The proliferation of AR42J cells by nicotine is associated with activation of MAPK signals and induction of protein oxidation. Resveratrol suppressed lipid peroxidation and P-ERK activated signals induced by nicotine. We conclude that resveratrol acts as an effective antioxidant in reversing the nicotine induced pancreatic cancer cell proliferation.