ER-α36 mediates tamoxifen induced activation of the MAPK/ERK in Hec1A cells.

<p>A and B, Hec1A cells were treated with 10 nM E2 or 2 µM Tam for the indicated time points. Levels of ERK1/2 phosphorylation were measured in protein extracts with Western blot analysis. Total ERK1/2 was used as loading control. Each bar represents mean value ± SEM (n = 3). *, P<0.05 compared to untreated cells. C and D, ER-α36 expression in Hec1A/V and Hec1A/RNAi cells. Each bar represents mean value ± SEM (n = 3). *, P<0.05 compared to Hec1A/V cells. E, Hec1A/V and Hec1A/RNAi cells treated with 10 nM E2 or 2 µM Tam were analyzed for the levels of ERK1/2 phosphorylation with Western blot. Total ERK1/2 was used as loading control, and each bar represents mean value ± SEM (n = 3). *, P<0.05 compared to untreated cells (−) vs. treatments. F, Lysates from Hec1A cells treated with DMSO (Lanes 1, 2 and 3), 10 nM E2 (Lanes 2 and 5), 2 µM Tam (Lanes 3 and 6) or pretreated with 10 µM U0126 (Lanes 4, 5 and 6) for 30 min were analyzed with Western blot analysis.