Fig. 7
Cigarette smoking evokes the activation of AKT-p70S6K signaling via miR-25-3p in PDAC. a CSC evokes the activation of AKT-p70S6K signaling via miR-25-3p in PDAC cells. b, c Exposure to CSC significantly enhanced the ability of proliferation (b) and migration and invasion (c) in PDAC cells. Scale bars, 200 μm. Right panel shows quantitative statistics. Results are mean ± S.D. from three random fields. d Correlations between miR-25-3p and METTL3 RNA levels and between PHLPP2 RNA and miR-25-3p or METTL3 RNA levels in smokers’ non-tumor pancreatic tissues (N = 67, left panel) and PDAC (N = 67, right panel) by Pearson’s test. e Correlations between miR-25-3p and METTL3 RNA levels and between PHLPP2 RNA and miR-25-3p or METTL3 RNA levels in nonsmokers’ non-tumor pancreatic tissues (N = 108, left panel) and PDAC (N = 108, right panel) by Pearson’s test. f Western blot analysis of protein expression levels of indicated genes in non-tumor tissues from nonsmokers (N = 18, upper panel) or smokers (N = 18, lower panel). R, the same positive reference sample for loading adjustment on each gel. Each protein band was semi-quantified by gray density and the value for each band is relative to density of both β-ACTIN and the corresponding band of R. g Significant difference in the expression levels of indicated proteins in non-tumor tissues from nonsmokers or smokers (both N = 18). Data are displayed in min to max boxplot. The line in the middle of the box is plotted at the median while the upper and lower hinges indicated 25th and 75th percentiles. *P < 0.05, **P < 0.01, and ***P < 0.001 by Student t test. h Significant Pearson correlations among the expression levels of METTL3, PHLPP2, p-AKT, and p-p70S6K proteins in smokers’ non-tumor tissues (N = 18). i Shown are Pearson correlations between METTL3, PHLPP2, p-AKT, and p-p70S6K protein expression levels in non-tumor tissue specimens from nonsmokers (N = 18). Data of (g–i) were from western blot analyses showing in (f). j A proposed action model for excessive miR-25-3p maturation via m6A modification stimulated by cigarette smoking in the development and progression of PDAC
