Figure 4.
CTR1 level is elevated in cisplatin-resistant cells. (A) Immunoblot showing the level of CTR1 protein in KB-3-1, KB-CP.5, KB-CP20, BEL-7404, BEL-7404-CP1, and BEL-7404-CP20 cells. Immunoblots with GAPDH are used as loading controls. (B) [3H]NSC73306 accumulation in KB-3-1 and KB-CP20 cells. (C) [3H]NSC73306 accumulation in KB-3-1, KB-CP20, and KB-CP20 cells treated with scrambled siRNA or CTR1 siRNA. (D) Sensitivity of KB-3-1, KB-CP.5, and KB-CP20 cells to NSC73306. Cells were incubated with increasing concentrations of NSC73306 for 72 h at 37 °C. Cytotoxicity was determined by MTT assays, and the survival curves were plotted. Results are means ± SD of 3 independent experiments.