Long-Term Alteration of Reactive Oxygen Species Led to Multidrug Resistance in MCF-7 Cells

Figure 8

ROS-induced MDR in MCF-7 cells was correlated with upregulation of MRP1 and P-gp. (a) MRP1 and P-gp protein expression levels were determined by western blot assay. 1, MCF-7/ADM cells; 2, MCF-7 cells (control); 3, MCF-7 cells treated with 0.1 μM ADM; 4, MCF-7 cells treated with 0.1 μM ADM + 2 mM GSH; 5, MCF-7 cells treated with 0.001 μM H₂O₂; 6, MCF-7 cells treated with 0.01 μM H₂O₂; 7, MCF-7 cells treated with 0.1 μM H₂O₂; 8, MCF-7 cells treated with 0.1 mM GSH; the treatment duration was 20 weeks. (b) Effects of H₂O₂ (0.1 μM) treatment on protein expression levels of MRP1 and P-gp were determined by western blot. Samples were obtained at the 6th, 8th, 10th, 12th, 14th, 16th, 18th, and 20th week of H₂O₂ incubation. (c) MRP1 and (d) P-gp were labeled by double fluorescence staining using DAPI and FITC-labeled antibodies. (A)–(C) MCF-7 cells; (D)–(F) MCF-7/ROS cells (MCF-7 cells treated with 0.1 μM H₂O₂ for 20 weeks). The confocal fluorescence image was captured at magnification of 400x, scale bar = 25 μm. Data represents the mean ± SD, . Significant differences relative to control group were indicated as and .

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