Figure 2.

GAS5 Was Associated with ADR Resistance of Breast Cancer Cells

(A) Cells were exposed to a series dose of ADR (0.02, 0.1, 0.5, 2.5, 12.5, and 25 μg/mL for MCF-7, and 0.5, 1, 5, 25, 125, 250 μg/mL for MCF-7/ADR) for 48 h; the cell viability of cells and the 50% inhibitory concentration (IC₅₀) of ADR were then detected using a CCK-8 assay. (B) MCF-7/ADR cells were transfected with pcDNA-GAS5, and MCF-7 cells were introduced with two synthesized individual GAS5 siRNAs (si-GAS5#1 and si-GAS5#2). The GAS5 expression was detected by quantitative real-time PCR. (C) pcDNA-GAS5-transfected MCF-7/ADR cells and si-GAS5#1- or si-GAS5#2-transfected MCF-7 cells were treated with various concentrations of ADR for 48 h, and IC₅₀s of ADR and cell proliferation capacity were measured by a CCK-8 assay. (D) The colony-forming ability was measured by a colony-forming assay. (E) Cell apoptosis was evaluated by flow cytometry. (F) Representative fluorescence-activated cell sorting (FACS) histograms of Rh123 accumulation and intensity of Rh123 fluorescence in pcDNA-GAS5-transfected MCF-7/ADR cells and in si-GAS5#1-transfected MCF-7 cells. (G) The ABCB1 mRNA expression was examined by quantitative real-time PCR. (H) The ABCB1 protein expression was examined by western blot analysis. Data are shown as the mean ± SD (n = 3). *p < 0.05, **p < 0.01 versus respective control.