| Objective: Osteosarcoma(OS)is a kind of malignant bone tumor that often occurs in adolescents.Chemotherapy resistance is an important reason that affects the prognosis of OS.The purpose of this study was to verify the differential expression of miRNA-331-3p and autophagy in OS cell line and cisplatin-resistant cell line,to explore the role of autophagy in cisplatin(CDDP)resistance of OS and whether miRNA-331-3p affects CDDP resistance of OS by regulating autophagy.Methods: OS cell lines(MG63,HOS)and their cisplatin-resistant cell lines(MG63/CDDP,HOS/CDDP)were constructed.The expression of miRNA-331-3p m RNA and autophagy in MG63,HOS,MG63/CDDP and HOS/CDDP were detected by q RT-PCR test and MDC staining.After miRNA-331-3p inhibitor was transfected into MG63/CDDP and HOS/CDDP,the cells were divided into MG63 group,MG63/CDDP group,MG63/CDDP+miR-331-3p inhibitor group,HOS group,HOS/CDDP group and HOS/CDDP+miR-331-3p inhibitor group.The proliferation and autophagy level of CDDP-treated cells in different groups were compared by MTT,q RT-PCR and Western Blot experiments.Finally,statistical methods were used to analyze the proliferation and autophagy level of cells treated with CDDP between the two major groups.Results: The expression of miRNA-331-3p in MG63/CDDP and HOS/CDDP was significantly higher than that in MG63 and HOS(P<0.05).The autophagy level of MG63/CDDP and HOS/CDDP was significantly higher than that of MG63 and HOS(P<0.05).After CDDP treatment,the results of MTT experiment showed that the proliferation ability of MG63/CDDP and HOS/CDDP was significantly higher than that of MG63 and HOS(P<0.05),and the proliferation ability of MG63/CDDP and HOS/CDDP inhibited by miRNA-331-3p was significantly lower than that of MG63/CDDP and HOS/CDDP(P<0.05).The results of q RT-PCR and Western Blot assay showed that the autophagy level of MG63/CDDP and HOS/CDDP was significantly higher than that of MG63 and HOS(P<0.05),while the autophagy level of MG63/CDDP and HOS/CDDP inhibited by miRNA-331-3p was significantly lower than that of MG63/CDDP and HOS/CDDP(P<0.05).Conclusion:(1)The expression of miRNA-331-3p and autophagy in cisplatin-resistant OS cell line were significantly up-regulated.(2)Autophagy can play a cytoprotective role and promote the formation of CDDP resistance in OS cells.(3)miRNA-331-3p participates in the regulation of autophagy.Inhibition of miRNA-331-3p expression can effectively reduce the autophagy level of cisplatin-resistant OS cell line,increase the chemosensitivity of cisplatin-resistant OS cell line to CDDP,and reverse the CDDP chemotherapy resistance of cisplatin-resistant OS cell line.(4)miRNA-331-3p may be an effective target for the treatment of drug-resistant OS. |
