Figure 3

Activation of Erk1/2 responses to E2, G1 or Tam in MCF-7 and TAM-R cells. Erk1/2 expression was investigated by western blot using specific antibodies against phosphorylated (p) and total (t) Erk1/2 protein. Cells were cultured for the indicated times with 1 nM E2 (A), 10 nM G1 (B) or 1 μM Tam (C) before preparation of cell lysates and western blot analysis. t-Erk1/2 expression was used as loading control. E2, 17β-estradiol; Tam, 4-hydroxytamoxifen; TAM-R, tamoxifen resistant.