Figure 4

Anti-apoptotic effect of claudin-1 induced by tamoxifen in MCF-7 cells. (A) MCF-7 cells were transfected with control siRNA or siRNAs against claudin- 1 (left: claudin-1 siRNA, right: claudin-1 siRNA2) and incubated for 48 h, before being treated with or without 40 μM of tamoxifen and then incubated for a further 20 h. Cell lysates were prepared from the cells and subjected to Western blot analyses for claudin-1, cleaved PARP, cleaved caspase-8, E-cadherin, β-cadherin, Bax, Bcl-2, cyclinD1, p53, p21, and actin. One representative of at least three independent experiments with similar results is shown. (B) The intensity of the bands for claudin-1, cleaved PARP, E-cadherin, β-cadherin and cyclinD1 in control siRNA and claudin-1 siRNA - treated cells with or without tamoxifen (40 μM) for 20 h were quantified.