The Role And Mechanism Of Exosome-mediated MicroRNA In Lung Adenocarcinoma Cells Resistant To Cisplatin

Objection:To detect the role and possible mechanism of exosomes in lung adenocarcinoma cell resistance to cisplatin.Material and methods:Exosomes were isolated by ultracentrifugation,observed by Transmission electron microscope and analyzed by Western blot.CCK-8 assay was used to measure cells' sensitivity to drug.Flow cytometry was used to evaluate the apoptotic rate and the changes of cell cycle.Microarray was employed to analyze miRNA expression profiles of A549 cells,A549/DDP cells,A549 exosomes and A549/DDP exosomes.MiR-100-5p was the most prominent decreased miRNAs in cisplatin resistant exosomes compared with corresponding sensitive ones and was selected for further study.Transfection of cells using liposome Lipofectamine 2000.In vivo and in vitro experiments,qRT-PCR and Western blot were used to detect the expression level of miR-100-5p and mTOR in cells and exosomes.The expression of mTOR protein in cells and tissues was detected by Western blot and immunohistochemistry.Results:Exosomes from A549/DDP can transfer DDP resistance to A549.There was a strong correlation of miRNA profiles between exosomes and their maternal cells.Downregulated miR-100-5p was proved to be involved in cisplatin resistance in A549 cells and mTOR expression was reverse regulated by miR-100-5p.Exosomes confer recipient cells' resistance to cisplatin was in exosomal miR-100-5p dependent manner with mTOR as it potential target both in vitro and in vivo.Conclusion:Exosomes from cisplatin resistant lung cancer cells A549 can alter recipient cells' sensitivity to cisplatin in exosomal miR-100-5p-dependent manner.Our study provides new insights into the molecular mechanism of cisplatin resistance in lung cancer.