Figure 5.
Ectopic ZEB1 confers antiestrogen resistance in breast cancer cells. (a and b) ZEB1/MCF-7 and Ctrl/MCF-7 cells were treated with different concentrations of tamoxifen for 72 h. Cell growth inhibition was determined by cell viability (a) and EdU proliferation (b) assays. *P<0.05, **P<0.01 versus the respective control in one-way analysis of variance (ANOVA) followed by Tukey's honestly significant difference test. (c and d) shZEB1/231 and shCtrl/231 cells were treated with different concentrations of tamoxifen for 72 h. Cell growth inhibition was determined by cell viability (c) and EdU proliferation (d) assays. *P<0.05 versus the respective control in one-way ANOVA followed by Tukey's honestly significant difference test. (e and f) An ER-α expression plasmid was transfected into ZEB1/MCF-7 cells, which were then treated with 10−6 M tamoxifen for 72 h. (e) The expression of ZEB1 and ER-α were assessed by immunoblotting and normalized to the levels of β-actin. (f) Cell growth inhibition was determined by EdU proliferation assays. ***P<0.001 versus the respective control in one-way ANOVA followed by Tukey's honestly significant difference test