A Preliminary Study About MiR-25 Inhibitor’s Effect To Lung Adenocarcinoma Cell A549 / DDP

Objective:(1).To study the effect of MicroRNA-25 inhibitor on the proliferation, apoptosis and cisplatin resistance of A549/DDP cells.(2). And discuss the possible mechanism Methods:To culture human lung adenocarcinoma A549 and A549/DDP cell strain, test DDP’s IC50 to both cell strain; Transfect miR-25 inhibitor into A549/DDP cells, then extract entire RNA and evaluate miR-25 inhibitor’s transfection effect with qPCR method; After transfecting inhibitor into A549/DDP cells, measured proliferation inhibition rate with CCK8 method when transfected 24 h, 48 h, 72 h, including transfect group, NC group and no-handle group cell, and measured three groups’ apoptosis rate with flow cytometry after transfecting mir25 inhibitor 72 h later; Set two groups, the transfect inhibitor group and NC group, then measured cisplatin’s IC50 to the two groups with cck8 method; Analysis expression of the inhibit cancer protein PTEN before and after transfecting inhibitor, with cell climbing slice immunity cell chemistry and digital pathology scanning system.Testing the change of PTEN’s mRNA with qPCR after inhibitor’s transfection. Results:(1). A549 cell lines’ IC50 was 0.591μg/ml, 95% credible interval was 0.436μg/ml ~ 0.753μg/ml; IC50 of A549/DDP cells was 9.040μg/ml, 95% credible interval was 6.504μg/ml ~ 14.783μg/ml, A549/DDP’IC50 was about 15.29 times of A549’s.(2).Compared with negative control group and no-handle group, miR-25 content decreased obviously in A549/DDP cells that transfected with miR-25 inhibitor, also the proliferation was significantly inhibited, the apoptosis rate increased obviously, the cisplatin’s effect to proliferation inhibition was improved obviously and the IC50 decreased. A549/DDP cells’ tolerance multiple was reversed.(3).Cell climbing slice immunohistochemistry and positive expressed grey value analysis: inhibitor group’s gray scale was: 139.7±2.52, NC group’s gray scale was: 194±4.58, showed that the protein expression of inhibitor group improved obviously,compared with NC group.(t test, P< 0.05). mRNA detection: after the inhibitor’s transfection,the mRNA of PTEN in inhibitor group was: 96.53±1.37, significantly increased than 57.27±4.53 in the NC group(t test, P< 0.05) Conclusion:miR-25’s specific inhibitor can significantly reduce the expression of endogenous miR-25 in lung adenocarcinoma cells, inhibit the proliferation activity and increase the apoptosis rate, when used with certain concentration cisplatin, it can improve the lung adenocarcinoma cells’ sensitivity to cisplatin, reverse its tolerance multiple, and the effect above may be associated with the recovery rise of the mRNA of PTEN and the PTEN protein in the cell.