Figure 5

MiR-503 influences EMT through PI3K/Akt/mTOR/Snail signaling pathway in HBE cells. (a) Western blot analysis was performed to detect the protein expression levels of Akt, phosphorylated-Akt, mTOR, phosphorylated-mTOR and Snail in mouse lung tissues. And the immunosignals were quantified by using densitometric scanning software ImageJ. The relative protein levels of p-Akt were normalized with total levels of Akt, and the relative protein levels of p-mTOR were normalized with total levels of mTOR, *P < 0.05 and **P < 0.01 versus the control group. (b,c) The protein expression levels of p-Akt, p-mTOR and Snail in HBE cells were gradually increased when treated with different concentrations of silica for 48 h and 200 μg/ml silica for different time points, *P < 0.05 and **P < 0.01 versus the control group. (d) The miR-503 agomir were tail-injected into the mice for 28 days and decreased the protein expression levels of p-Akt, p-mTOR and Snail in mouse lung tissues of the model, *P < 0.05 and **P < 0.01 versus the SiO₂ + miR-NC agomir group. (e) miR-503 mimics were transfected to HBE cells for 48 hours and significantly decreased the protein levels of p-Akt, p-mTOR and Snail, *P < 0.05 and **P < 0.01 versus the SiO₂ + miR-NC mimic group. (f) The transfection of PI3K p85 siRNA together with the silica treatment for 48 hours significantly reduced the expression of p-Akt, p-mTOR and Snail, *P < 0.05 and **P < 0.01 versus the SiO₂ + siRNA control group. (g) Co-transfection with PI3K p85 overexpression plasmid and miR-503 mimics for 48 hours restored the protein expression levels of p-Akt, p-mTOR and Snail which were inhibited by miR-503 mimic, *P < 0.05 and **P < 0.01 versus the SiO₂ + mimic + p85 vector group.