Epigallocatechin-3-gallate promotes apoptosis in human breast cancer T47D cells through down-regulation of PI3K/AKT and Telomerase

BackgroundGreen tea has antioxidant, anti-tumor and anti-bacterial properties. Epigallocatechin-3-gallate (EGCG) in green tea is highly active as a cancer chemopreventive agent. In this study, we designed a series of experiments to examine the effects of EGCG on proliferation and apoptosis of estrogen receptor α-positive breast cancer (T47D) cells.MethodsCells were treated with EGCG (0-80 μM) and tamoxifen (0-20 μM), as the positive control, up to 72 h. Cell viability was determined by MTT assay. Apoptosis investigated by real time PCR of apoptosis and survival (Bax, Bcl-2, p21, p53, PTEN, PI3 K, AKT, caspase3 and caspase9 and hTERT) genes and by western blot of Bax/Bcl-2 proteins expressions.ResultsThe results showed that EGCG decreased cell viability as concentration- and time-dependently. IC50 values were 14.17 μM for T47D and 193.10 μM for HFF cells, as compared with 3.39 μM and 32.75 μM for tamoxifen after 72 h treatment, respectively. Also, EGCG (80 μM) significantly increased the genes of PTEN, CASP3, CASP9 and decreased AKT approximately equal to tamoxifen. In gene expression, EGCG (80 μM) significantly increased Bax/Bcl-2 ratio to 8-fold vise 15-fold in tamoxifen (20 μM)-treated T47D cells during 72 h. In protein expression of Bax/Bcl-2, EGCG significantly increased 6-fold while this ratio augmented 10-fold in tamoxifen group. EGCG significantly decreased 0.8, 0.4 and 0.3 gene expression of hTERT in 24, 48 and 72 h, respectively.ConclusionsThis study suggests that EGCG may be a useful adjuvant therapeutic agent for the treatment of breast cancer.