Effect of EGFR on epithelial-mesenchymal transition of type II alveolar epithelial cells induced by TGFβ1

Objective To investigate the effect of epidermal growth factor receptor(EGFR) expression on epithelial-mesenchymal transition(EMT) of type Ⅱ alveolar epithelial cells induced by TGFβ1.Methods The in vitro cultured type Ⅱ alveolar epithelial cell line-A549 cells were treated with TGFβ1 at different time points to observe its cellular morphology changes under phase-contrast microscope.The cells at different time point were collected to assay mRNA expression of E-cadherin and α-smooth muscle actin(α-SMA) by RT-PCR before and after A549 cells being treated by TGFβ1,and protein expression of E-cadherin,α-SMA and phosphorylated EGFR(p-EGFR) were detected by Western blot.Results After TGFβ1 treatment,A549 cells were turned from cobblestone into spindle-shaped,a myofibroblast-like morphology.Protein and mRNA expression of E-cadherin were down regulated(P0.05),but protein and mRNA expression of α-tSMA and p-EGFR were up regulated(P0.05).Conclusion TGFβ1 can induce EMT of alveolar epithelial cells in vitro,where the mechanism is associated with activation of EGFR-related signaling pathway.Inhibition of EGFR activation may be used as a novel therapeutic agent for the pulmonary fibrosis.