Figure 3.

DXR resistance and nuclear DXR accumulation in CD44⁺CD133⁻ and CD44⁺CD133⁺ cells, in the absence or presence of drug efflux inhibitor. (a) MTT assay was done to compare the cytotoxicity of DXR in CD44⁺CD133⁻ and CD44⁺CD133⁺ cells, with or without the addition of 50 μM verapamil. Data were expressed as a percent of baseline (before DXR treatment) from three independent experiments. ^∗P < 0.05 vs. CD44⁺CD133⁻ cells. (b) Representative histograms of flow cytometry analysis showed the nuclear accumulation of DXR in cells 24 hr after the treatment by 10 μM DXR, with or without the addition of 50 μM verapamil. The results were reproducible in three independent experiments.