Abstract: Objective To investigate the effect and mechanism of overexpression of microRNA-193b-5p ( miR-193b-5p) on cisplatin ( DDP) -resistant cell line SiHa / DDP in human cervicalcancer. Methods Human cervical cancer cell line ( SiHa) and its cisplatin-resistant cell line( SiHa / DDP) were cultured. The survival rates of the two cell lines treated with DDP (5, 10, 15, 20, 25, 30 μmol / L) were detected by MTT assay, and the half inhibitory concentration ( IC50 ) value was determined. Cells were divided into 4 groups: SiHa group, SiHa / DDP group, mimics NC group ( SiHa / DDP cells transfected with mimics NC), miR-193b-5p mimics group ( SiHa / DDP cells transfected with miR-193b-5p mimics). The expression level of miR-193b-5p was detected by RT-qPCR. Cells were then treated with DDP, and the cell survival rate and apoptosis rate were detected by the MTT method and flow cytometry. The expression of microtubule-associated protein 1 light chain 3 B (LC3B) was detected by cell immunofluorescence staining, and the protein expression levels of LC3Ⅱ / LC3Ⅰ , Beclin-1, and P62 were detected by Western blotting. Results Thesurvival rate of SiHa / DDP cells was higher than that of the SiHa cells when treated with DDP at thesame concentration (P< 0. 05), and the IC50 value of cells was significantly increased (P< 0. 05).The relative expression level of miR-193b-5p in the SiHa / DDP cells was significantly downregulated(P< 0. 05). The relative expression level of miR-193b-5p in the miR-193b-5p mimics group was higher than that in the control group and mimics NC group (P< 0. 05). Compared with those in theSiHa / DDP group and the mimics NC group, the survival rate of SiHa / DDP cells in the miR-193b-5p mimics group was significantly decreased, the apoptosis rate was significantly increased ( P <0. 05), the fluorescence intensity of LC3B in cells was significantly weakened, the LC3Ⅱ / LC3Ⅰratio and the relative expression level of Beclin-1 protein were significantly downregulated ( P <0. 05), and the relative expression level of P62 protein was significantly upregulated (P < 0. 05).Conclusion The expression level of miR-193b-5p was decreased in the cisplatin-resistant cell lineSiHa / DDP of human cervical cancer. Its overexpression could reverse the resistance of SiHa / DDPcells to DDP, which may be related to its inhibition of cell autophagy.

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