The Effects Of Autophagy In The ACEs To Ionizing Radiation-induced EMT

Objective Radiotherapy is a common method of clinical treatment of malignant tumors,but radiation-induced radioactive pulmonary fibrosis is the most difficult complication of radiotherapy.The pathological character of pulmonary fibrosis is fibroblast aggregation,the injury of alveolar type II epithelial cell,collagen and extracellular matrix deposition.Previously radiation could induce epithelial-mesenchymal transition?EMT?in alveolar epithelial cells?AECs?,and develop into fibroblasts,which is an important cellular source of radioactive pulmonary fibrosis.Autophagy is a highly conserved cell behavior that sustains the steady state of the environment in resting and stressful conditions,which can degradation of proteins by assembly of autophagosomes and lysosomes.The occurrence of autophagy is mainly characterized by the induced expression of LC3I/II and Beclin-1,and the degradation of p62.The previous study has shown that the expression of ?-catenin,the important EMT signal pathway protein,increased in the lung tissue epithelial cell cytoplasm and nucleus,So the formation of radioactive pulmonary fibrosis was promoted.This study talked about the role of autophagy in the process of EMT which caused pulmonary fibrosis by radioactive,and explored autophagy mediate EMT by Wnt/?-catenin pathway.Therefore,we further revealed the molecular mechanism of radiation-induced alveolar EMT and provided new clues for the pathogenesis and prevention of pulmonary fibrosis.Methods Beas-2B cells was treated with 6 Gy⁶⁰Co?-ray irradiation,The induced expression and activation of EMT,HIF-1?,autophagy and Wnt/?-catenin pathway protein were tested by western blotting assay.Laser confocal microscopy was used to detect the expression of EMT surface protein.The change of EMT phenotype was analyzed by Flow Cytometry.Results 6Gy⁶⁰Co?-ray irradiation induced the occurrence of EMT.Radiation-induced EMT model was established,accompanied by the induced expression of HIF-1?,which forms a hypoxic microenvironment.LC3I/II and Beclin-1 expression was increased,and the expression of p62 was inhibited,which means autophagy induction.The expression of ?-catenin protein was increased with⁶⁰Co?-ray irradiation.Moreover,when the expression of EMT-related protein was inhibited by knocking down expression of ?-catenin,and the expression level of autophagy-related protein did not change significantly.Therefore,inhibition of autophagy induction,the activation of Wnt/?-catenin signaling pathway was significantly blocked,and EMT-related protein expression was attenuated in Beas-2B cells.Conclusion The induced expression of HIF-1? is critical in medicating⁶⁰Co?-ray irradiation induced autophagy,the activation of Wnt/?-catenin signaling pathway and epithelial interstitial transformation in human bronchial epithelial cells.