Growth inhibition and apoptosis by (-)-epicatechin gallate are mediated by cyclin D1 suppression in head and neck squamous carcinoma cells.

In recent studies, green tea components have been shown to induce cell growth arrest and apoptosis in head and neck squamous cell carcinoma (HNSCC) cells. In this report, we have investigated the effects of epicatechin gallate (ECG), one of the catechins in green tea, on anti-cancer activity in vitro. We found that cyclin D1 was highly expressed in HNSCC cells, and ECG suppressed 90% of cyclin D1 expression in SCC7 cells. We have also evaluated the effect of ECG on cell growth and apoptosis, showing that ECG (50 microM) exhibited a significant inhibition (50%) on the growth of SCC7 cells via G1 cell cycle arrest. ECG suppressed cyclin D1 in SCC7 cells in a dose- and time-dependent manner, and the suppression of the beta-catenin pathway by ECG is one of the mechanism to facilitate ECG-induced cell growth arrest. These results suggest that ECG has a potential usage as a chemopreventive agent in HNSCC.