miR-98 regulates cisplatin-induced A549 cell death by inhibiting TP53 pathway.

To explore the possible microRNAs (miRNAs) in the TP53 pathway and their roles in A549 cell death induced by cisplatin, the miRNAs relative to 3'-untranslated region (3'-UTR) of TP53 were predicted by microRNA analysis softwares, which showed that TP53 expression might be targeted by miR-98, miR-453 and miR-485. Then, GFP was used as a reporter gene to reflect whether the 3'-UTR of TP53 was targeted by the predicted miRNAs. After pcDNA-GFP-UTR was constructed, the GFP expression was estimated in A549 cells by the examination of fluorescence microscopy and flow cytometry. The intensity of fluorescence in the miR-98 and miR-453 groups decreased significantly compared with the control group. The percentage of positive GFP cells in miR-98 and miR-453 groups were 30.24% and 32.58%, respectively, much lower than that of NC group (41.86%). The TP53 expression was inhibited after transfection with miR-98/miR-453 by western blot. As the factors in TP53 pathway, Bcl-2 expression was found to be enhanced, and the expression of miR-34a-c was decreased in A549 cells after miR-98/miR-453 treatment. Moreover, the expression of miR-98 and Bcl-2 was decreased, while miR-34a-c and TP53 was increased after A549 treated with cisplatin. Our study demonstrated that miR-98 and miR-453 down-regulated TP53 expression by targeting the 3'-UTR of TP53, and that cisplatin might inhibit A549 cell growth by miR-98 regulating TP53 pathway. Our results indicated that TP53 relevant miRNAs might be the new targets for gene therapy or new drug design.