Fig. 4

Up-regulation of ER-α36 leads to increased activation of nongenomic estrogen signaling. a MCF-7 cells were treated with or without 5 μg/mL cisplatin (DDP) for 48 h. Then the protein levels of EGFR, HER-2, ER-α36, total ERK (ERK) and phosphorylated ERK (P-ERK) were detected using western blot. b, c The quantitative analysis of cisplatin-induced expression of ER-α36, EGFR, HER-2 and P-ERK/ERK of (a). d MCF-7, BT474 and MDA-MB-231 cells were treated with cisplatin at the indicated concentrations for 48 h and then the protein levels of EGFR, HER-2, ER-α36, ERK and P-ERK were analyzed by western blot. e The quantitative analysis of cisplatin-induced expression of P-ERK/ERK of (d). f MCF-7 cells were treated as in (a). The cell lysates were immunoprecipitated with anti-HER-2 or anti-EGFR antibodies. Then the immunoprecipitates were separated by SDS-PAGE and probed with anti-ER-α36 antibodies. Immunoprecipitation of IgG was used as a negative control