Autophagy Confers Chemoresistance To Cisplatin In Lung Adenocarcinoma A549/DDP Cells

ObjectiveTo explore the role and the underlying regulation mechanism of autophagy in cisplatin resistance of A549/DDP cells.MethodsThe resistance of A549/DDP cells and their parental A549 cells to DDP was detected by MTS and the resistance index of A549/DDP cells was calculated.The autophagy activity in A549/DDP cells and their parental A549 cells was detected by Western blot,Transmission electron microscope and Confocol.A549/DDP cells were treated with DDP.Western blot and RT-qPCR were used to detect the effects of DDP on autophagy-related proteins and gene expression.A549/DDP cell model with autophagy-related gene knockdown was constructed and the effect of autophagy on DDP resistance was verified by MTS.ResultsA549/DDP cells have higher DDP resistance than their parental A549 cells and the resistance index was about 6.22.It is a medium resistant cell line.The expression levels of key autophagy proteins such as LC3 B,ATG5,Beclin1 and ATG7 were significantly higher in A549/DDP cells than in A549 cellsDDP treatment could lead to decrease the expression levels of key autophagy proteins such as LC3 B,ATG5,Beclin1 and ATG7 and the expression levels of key autophagy gene such as ATG5、Beclin1 and ATG7 in a dose-dependent and time-dependent manner.DDP could inhibit the expression of autophagy-related genes and proteins though inhibiting AMPKα and MiTF signaling pathways.A549/DDP cells treated with DDP after knocking out ATG5 or BECN1 genes can significantly increase cell mortality.ConclusionA549/DDP cells have higher DDP resistance and higher autophagy activity,and DDP treatment can repress autophagy might through inhibition of AMPKα and MiTF.Autophagy plays protective role in response to DDP treatment and inhibition of autophagy leads to aggravated cell death induced by DDP treatment,indicating that inhibition of autophagy can reverse DDP chemoresistance in A549/DDP cells.