Fig. 1

E2 upregulates the expression of CLDN6 in MCF-7 and MDA-MB-231 cells. MCF-7(a), MDA-MB-231(b) and SK-BR-3(c) cells were treated with DMSO or E2 (from 5 nM to 100 nM). Cells were harvested after 24 h treatment for analysis of gene and protein expression of CLDN6 using semiquantitative RT-PCR and western blot, respectively. Actin served as a loading control. Quantification of CLDN6 expression in MCF-7 (d) and MDA-MB-231 (e) cells cotreated with ICI by qRT-PCR. CLDN6 protein expression levels in MCF-7 (f) and MDA-MB-231 (g) cells after treatment with E2 or E2/ICI. CLDN6 protein expression in SK-BR-3 (f) cells after 50 nM E2 treatment. Wound healing and Transwell assays were used to detect the migration (scale bar, 200 μm) and invasion (scale bar, 50 μm) abilities of MCF-7 (h) and MDA-MB-231 (i) cells treated with E2. Data are presented as mean ± SD. The data shown are representative results of three independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001