Figure 1

EGCG and TSA synergistically induced ERα re-expression in ERα-negative MDA-MB-231 breast cancer cells. A) Graphic presentation of dose-dependent cellular growth inhibition by EGCG treatment. MDA-MB-231 cells were exposed to various concentrations of EGCG (0, 5, 10, 25 and 50 μM) for 3 days. B) Effects of cellular viability by the combined treatment of EGCG with 5-aza (left) and TSA (right). The MDA-MB-231 cells were treated with or without either 10 μM EGCG or 2 μM 5-aza and 100 ng/ml TSA alone or together for 3 days. C) EGCG induced ERα re-expression in ERα-negative breast cancer cells. The MDA-MB-231 cells were treated with various concentrations of EGCG as described above. D) EGCG induced maximal ERα re-expression at a concentration of 10 μM. The MDA-MB-231 cells were treated with additional concentrations of EGCG (7.5, 15 and 20 μM) to further determine the optimal concentration of EGCG on ERα reactivation. E) EGCG in combination with 5-aza (left) and TSA (right) enhances ERα transcription. Combination treatment was performed as described above. Quantitative real-time PCR was performed to measure relative transcription of ERα. Data are in triplicate from three independent experiments and were normalized to GAPDH and calibrated to levels in untreated samples. Bars, SD; *, P < 0.05, * * P < 0.001, significantly different from control. F) ERα protein expression with the treatment of EGCG or TSA alone or combination. MDA-MB-231 cells were treated with EGCG or TSA alone or in combination and MCF-7 cells served as positive control.