Figure 3.

Metformin (Met) inhibits expression of ERα in the MCF-7 and TR MCF-7 cells under E2. (A) MCF-7 and (B) TR MCF-7 cells were treated with Met (25 mM) in the presence of E2 (100 nM) for 48 h in estrogen-depleted RPMI-1640 medium containing 3% charcoal stripped FBS. Immunoblots were probed with the anti-ERα antibody (left panels). β-actin was evaluated as a loading control. ERα mRNA levels were determined by RT-qPCR after treatment of Met and E2 for 24 h (right panels). Data represent the mean ± SD of three independent experiments conducted in triplicates; ^*P<0.05.