Fig. 4.

The anion-channel blocker DIDS reduces Cisplatin-induced Erk-2 phosphorylation in A2780 cells. Whole cell protein lysates for Western blot analysis were obtained from A2780WT and A2780CisR cells exposed to 0, 10, or 20 μM Cisplatin for 14 h in combination with the anion/amino acid channel blockers DIDS (400 μM). Only A2780WT cells were exposed to DIDS. Total Erk-1/-2 protein and phospho-Erk-1/-2 expression were determined using specific antibodies (see experimental procedures). Histone-3 (H3) was used as loading control. A: representative Western blot. B: phospho-Erk-1 protein expression relative to total-Erk-1 (gray bars) and phospho-Erk-2 protein expression relative to total-Erk-2 (black bars) in A2780WT, A2780WT cotreated with DIDS, and A2780CisR control cells and following 14 h Cisplatin exposure. Data represent 5 individual sets of experiments, where ratios are given relative to the untreated WT cells ± SE. * and § indicate that the Erk-phosphorylation ratio is significantly increased in Cisplatin-treated cells when compared with the respective control cells; # indicates that the Erk-phosphorylation ratio in cisplatin-treated A2780WT cells is significantly reduced by DIDS (ANOVA, Fisher LSD method).