Fig. 7
Low expression of LINC00173 in DDP-resistant LUAD attributes to the negative regulation of c-Myc. a. Predicted c-Myc binding site in the promoter region of LINC00173. b. Transfection of c-Myc plasmids suppressed LINC00173 expression in A549 and PC9 cells. Student’s two-tailed t-test, **P < 0.01; ***P < 0.001; ****P < 0.0001. c. ChIP assay and agarose gel electrophoresis verified the binding of c-Myc to LINC00173 promoter in A549 and A549-DDP cells. Student’s two-tailed t-test, **P < 0.01; ****P < 0.0001. d. Luciferase reporter assay further validated c-Myc was directly binding to LINC00173 promoter. Student’s two-tailed t-test, *P < 0.05; **P < 0.01; ns, no significance. e. Western blot analysis of PI3K, p-PI3K, AKT, p-AKT and c-Myc expression in A549 and A549-DDP cells. GAPDH was used as a loading control. f. Western blot detection of p-PI3K, p-AKT, c-Myc, PROCA1 and ZFP36L2 expression in A549-DDP and PC9-DDP cells after treated with PI3K inhibitor LY294002. GAPDH was used as a loading control. g. The expression level of LINC00173 was obviously increased in A549-DDP and PC9-DDP cell lines after treated with LY294002. h. The IC50 values to cisplatin were detected in A549 and PC9 cells transfected with a gradient concentration of c-Myc plasmids. Student’s two-tailed t-test, **P < 0.01; ****P < 0.0001. Error bars, mean ± SD