Knockdown of lncRNA-XIST attenuates the chemoresistance of NSCLC cells via suppression of autophagy. (A) Analysis of lncRNA-XIST mRNA expression in parental A549 and DDP-resistance A549 cells (DDP A549). (B) Analysis of the autophagy activity in parental A549 cells and DDP A549 cells. (C) Both DDP A549 and parental A549 cells were transfected with Ctrl and Sh-X plasmid, respectively. After 24 h, DDP A549 cells were treated with cisplatin (0, 5, 10, 15, 20 and 25 µg/ml) and parental A549 cells were with cisplatin (0, 1, 2, 4, 8 and 16 µg/ml) for 48 h, and then cell viability was examined by CCK-8 assays. Data are shown as mean ± SD of three independent experiments. (D and E) DDP A549 cells were co-transfected with Ctrl and Sh-X plasmid or ATG7 plasmid and miR-17 inhibitor (miR-17Inh), respectively, and then, cell viability was examined by CCK-8 assays. Data are shown as the mean ± SD of three independent experiments. *P<0.05; **P<0.01; ***P<0.001.