Fig. 1.

231/DDP cell is resistant to cisplatin. a MTT assay is used to evaluate the chemo-sensitivity of 231/wt cells and 231/DDP cells to different drugs of DDP/CTX/Paclitaxel/DOX after 48 h treatment (N = 3, **P < 0.001, *P < 0.01); b, c annexin V/PI assay is used to detect apoptosis in 231/wt and 231/DDP cell lines with different concentration of DDP; d difference on intracellular accumulation of DDP between 231/wt and 231/DDP cell lines. ICP-MS method is used to detect intracellular DDP accumulation in cells treated with DDP 1 μg/mL for 24 h, **P < 0.001. e, f ABC transporters protein expressions of MRP2, P-gP and BCRP in both of 231/wt cells and 231/DDP cells