Resveratrol inhibits oral squamous cell carcinoma through induction of apoptosis and G2/M phase cell cycle arrest

The present study was performed to investigate the effect of resveratrol (trans-3,4′,5-trihydroxystilbene) present as a natural phytoalexin in grapes, peanuts, and red wine on oral squamous cancer cell lines, SCC-VII, SCC-25, and YD-38. MTS assay and flow cytometry, respectively, were used for the analysis of inhibition of cell proliferation and apoptosis. Western blot analysis was performed to examine the effect of resveratrol on the expression of proteins associated with cell cycle regulation. The results revealed a concentration- and time-dependent inhibition of proliferation in all the three tested cell lines on treatment with resveratrol. The IC₅₀ of resveratrol for SCC-VII, SCC-25, and YD-38 cell lines was found to be 0.5, 0.7, and 1.0 μg/ml, respectively, after 48-h treatment. Examination of the cell cycle analysis showed that resveratrol treatment induced cell cycle arrest in the G2/M phase and enhanced the expression of phospho-cdc2 (Tyr 15), cyclin A2, and cyclin B1 in the oral squamous cell carcinoma (OSCC) cells. It also caused a marked increase in the percentage of apoptotic cells as revealed by the fluorescence-activated cell sorting analysis. Thus, resveratrol exhibits inhibitory effect on the proliferation of OSCC oral cancer cells through the induction of apoptosis and G2/M phase cell cycle arrest.