ABSTRACT
Objective To examine the effect of epigallocatechin gallate (EGCG) at different concentration (0,10,25, 50 and 100μmol/L ) on proliferation rate and apoptosis of nasopharyngeal carcinoma cell line C666-1 in vitro, and elucidate the role of silent information regulator 1 (SIRT1). Methods The proliferation rate in vitro of C666-1 cells stimulated by EGCG at increasing concentrations (0,10,25,50,and 100 μmol/L)for 24 h or at concentration of 50μmol/L for 0,6,12 h and 24 h were detected by cell counting kit-8 (CCK-8) assays. Cell were treated with EGCG at concentration of 0,25, 50 and 100 μmol/L for 24 h, cell apoptosis was anylysed by TUNEL assay and expression levels of SIRT1 protein was detected by western blotting. Results EGCG suppressed cell proliferation of C666-1 cell line in a concentration-dependent manner at concentration of 0 ,10,25,50,and 100μmol/L, and in a time-dependently when treated with 50 μmol/L for 12 to 24 h(P<0.05). After treated for 24 h with different concentration of EGCG at 0、25、50、100 μmol/L, cell apoptosis increased at concentration of 50 to 100μmol/L and expression of SIRT1 decreased in a concentration-dependently (P<0.05). Conclusion EGCG induced cell apoptosis of C666-1 cells by down-regulating SIRT1 expression.