Figure 5

Co-treatment of coffee with tamoxifen specifically induces cell death only in MCF-7 cells. (A) T47D cells and MDM-MB-231 cells and (B) Murine embryonic fibroblast cells (MEF), HCT116 cells and U2OS cells were treated with coffee (1.25, 2.5, 5, 10, 20 v/v%) in the absence or presence of tamoxifen (0.6, 1.25, 2.5, 5, 10 μM) for 24 h. Cell viability was measured by the trypan blue exclusion method. Results represent the mean ± SD of three independent experiments. **p < 0.01, ***p < 0.001 significantly different from control cells. ^##p < 0.01, ^###p < 0.001 significantly different from cells treated with tamoxifen. (C, D) T47D cells, MDM-MB-231 cells, MEF, HCT116 cells and U2OS cells were treated with coffee (2.5, 5 v/v%) and MCF-7 cells were treated with coffee (5 v/v%) in the absence and presence of tamoxifen (5 μM) for 24 h. Whole cell lysates were immunoblotted with an anti-ERα antibody, anti-p53 antibody or anti-β-actin antibody. The relative expression levels of ERα and p53 are shown in the graphs. Results represent the mean ± SD of three independent experiments. **p < 0.01, ^###p < 0.001 significantly different from control cells and cells treated with 5 μM tamoxifen, respectively.