Fig. 6

17β-estradiol enhances PMCA4 expression specifically in MCF-7 and further enhances the HDAC inhibitor induced upregulation. Effects of 17β-estradiol (E2) ± HDAC inhibitor treatments on PMCA4 protein expression in ER-α positive breast cancer cell lines. a: MCF-7, ZR-75-1 and T-47D cells were cultured in E2-free culture medium and treated with 1 nM E2 ± 100 nM fulvestrant (fulv.) ± 4 mM VPA or 3 μM SAHA for 4 days as indicated. Equal amount (30 μg) of total cell lysates were analyzed by Western blotting with anti-PMCA4 (JA9), anti-ER-α and anti-ER-β antibodies. β-actin served as a loading control. b: Relative PMCA4 protein expression in the examined cell lines. Densitometric values were normalized to the respective β-actin levels and expressed as fold increase over the untreated controls. Bars represent mean ± SEM from three independent experiments. Significance is denoted by * (P < 0.05) or ** (P < 0.01); two-tailed paired t-test