Research On The Role And Mechanism Of MiR-4725-5p In The Regulation Of Proliferation,Migration And Cisplatin Resistance In Lung Cancer By CDH1

Objective: By analyzing the expression levels of micro RNA 4725-5p（miR-4725-5p）in the plasma of lung cancer（LC）patients and LC cell lines and its effects on lung cancer proliferation,migration,and cisplatin resistance through its target gene CDH1,we initially indicated the potential clinical significance of miR-4725-5p in lung cancer diagnosis and treatment,and the molecular mechanisms of miR-4725-5p in the regulation of lung cancer malignant phenotypes and cisplatin resistance.Methods: 1.Quantification of miR-4725-5p expression in the plasma of82 LC pateints and 114 healthy physical examiners by quantitative real-time PCR（qRT-PCR）assay;2.Quantification of miR-4725-5p expression in lung adenocarcinoma cell line A549 and normal human lung epithelial cell line BEAS-2B by qRT-PCR assay;3.Quantification of miR-4725-5p expression levels in A549 cell line transfected with miR-4725-5p mimic,miR-4725-5p mimic NC,miR-4725-5p inhibitor or miR-4725-5p inhibitor NC.4.A549 cell line transfected with miR-4725-5p mimic,miR-4725-5p mimic NC,miR-4725-5p inhibitor or miR-4725-5p inhibitor NC,combined or not combined with cisplatin treatment were measured by clone formation,CCK-8and scratch assay for the analysis of proliferation and migration;5.The downstream target genes of the miR-4725-5p was predicted by bioinformatics prediction websites including starbase3.0v and Targetscan;6.Survial curve analysis of miR-4725-5p targeting genes in LC by using KM Plotter online database;7.Protein expression level of miR-4725-5p targeting gene in A549 cell line transfected with miR-4725-5p mimic,inhibitor or controls by Westren blot.Results: 1.miR-4725-5p levels were significantly increased in the plasma of lung cancer patients relative to the healthy physical examination population,and were even higher in the plasma of chemotherapy-resistant lung cancer patients relative to chemotherapy-sensitive lung cancer patients;2.miR-4725-5p expression levels were overexpressed in lung adenocarcinoma cell line A549 relative to normal human lung epithelial cell line BEAS-2B;3.The expression level of miR-4725-5p was significantly increased in A549 cells transfected with miR-4725-5p mimic and decreased in A549 cells transfected with miR-4725-5p inhibitor,compared to miR-4725-5p mimic or inhibitor NC;The ability of colony-formation,proliferation and migration were increased in A549 cells transfected with miR-4725-5p mimic relative to miR-4725-5p mimic NC;the ability of colony-formation,proliferation and migration were decreased in A549 cells transfected with miR-4725-5p inhibitor relative to miR-4725-5p inhibitor NC;4.The ability of colony-formation,proliferation and migration were increased in A549 cells treated with cisplatin and transfected with miR-4725-5p mimic relative to miR-4725-5p mimic NC;the ability of colony-formation,proliferation and migration were decreased in A549 cells treated with cisplatin and transfected with miR-4725-5p inhibitor relative to miR-4725-5p inhibitor NC;5.CDH1 was predicted as one of the downstream target genes of miR-4725-5p based on database;6.Low m RNA levels of CDH1 was associated with poor prognosis of lung cancer patients;7.The protein level of CDH1 encoded protein,E-cadherin,was decreased and increased respectively with the transfection of miR-4725-5p mimic and inhibitor,compared with the miR-4725-5p mimic or inhibitor controls.Conclusion: miR-4725-5p was highly expressed in the plasma of LC patients and LC cell line.CDH1 could be one of the targets of miR-4725-5p.Moreover,miR-4725-5p could promote proliferation,migration and cisplatin-resistance in LC.