Lidocaine Induces Autophagy In A549 Cells By Inhibiting MTOR Signaling Pathway

It is well known that lidocaine have a broad spectrum of pharmacological actions,acting as nerve blocker,and anti-arrhythmic.Autophagy is a highly conserved process by which cells can recycle organelles and proteins by degrading them in the lysosomes.Autophagy can inhibit the occurrence and development of tumor.Lidocaine is related to apoptosis,invasion and migration of tumor,whether lidocaine play a role in autophgy is not clear.The purpose of the present study was to investigate the effect of lidocaine on autophagy and related mechanisms.Objective : In vitro experiments,The effects of lidocaine on autophagy were investigated whether promoting autophagy by inhibiting mTOR in A549 cancer cells.Methods : Human lung cancer A549 cells were treated with lidocaine,cell viability was quantitatively determined by MTT assay.The expression of p-mTOR and autophagy-related proteins LC3,Beclin-1 in the cells were determined by western blot analysis,and then GFP-LC3 plasmids was transfected in lidocaine treated A549 cells.The morphological features of cell autophagy were observed under electron microscope and fluorescence microscopes.Results: First,Lidocaine inhibites the survival of A549 cells in dose-dependent manner.With increasing concentration of lidocaine,the cell viability of A549 cells were gradually reduced,but the proliferation inhibition rate was increased.Second,The expression of autophagy related proteins were promoted by lidocaine.A549 cells were incubated with various concentration of lidocaine for 24 h,compared to the 0mM group,in A549 cells treated with 0.1mM lidocaine,the expression of autophagy related protein LC3-II,Beclin-1 were significantly up-regulate,but the expression of p-mTOR was reduced significantly.The morphological features of cell autophagy were observed under electron microscope,fluorescence microscope and electron microscopy assy results showed that the number of autophagosomes were increased.Third,Autophagy inhibitior 3-MA can inhibit the formation of autophagy induced by lidocaine in A549 cells.Compared with the control group,3-MA significantly down-regulated the expression of LC3-II and Beclin-1(P<0.05).Fourth,Lidocaine could promotes the production of autophagosome.Green spot was significantly increased after treated with 0.1mM lidocaine for 24 h and transfected with plasmids in A549 cells.The number of green spot was significantly decreased after treated with 3-MA,Reduced autophagosome number was present in A549 cells were observed under TEM.Conclusion: Lidocaine could inhibit the proliferation of A549 cells and promote autophagy;Lidocaine promote autophagy by inhibiting mTOR in A549 cells.