Effects And Mechanism Of Long Non-coding RNA MIR31HG In Human Ovarian Cancer Cells

Objective: Ovarian cancer is a common malignant tumor of the female reproductive system,and the mortality rate ranks first in gynecological malignancies.Because of its insidious onset,no obvious symptoms in early stage,and lack of effective early diagnosis Amethods,70% of patients are diagnosed in advanced stage.Although surgery,chemotherapy drugs and methods,molecular targeted drugs have made some progress,the efficacy of ovarian cancer is still not satisfactory,and the five-year survival rate does not exceed 35%.Therefore,early clarification of the mechanism of ovarian cancer development is of great significance in improving the therapeutic effect of ovarian cancer.MIR31HG?NCBI no;NR₀27054?is a recently discovered long non-coding RNA of 2166 bp located on chromosome 9p21.3.Many lncRNAs,including long non-coding RNA?lncRNA?MIR31HG,are involved in the development and progression of various tumors.However,the role and molecular mechanism of MIR31 HG in ovarian cancer are still unclear.It is important to explore the effect and mechanism of MIR31 HG on proliferation,apoptosis and invasion of human ovarian cancer cells SKOV3 and HO-8910 cells.Methods: The first part:1.The expression of MIR31 HG in 50 cases of ovarian serous epithelial carcinoma and 50 cases of normal ovarian tissue were analyzed by RT-qPCR.The MIR31 HG and clinicopathological features were analyzed by follow-up of patient data.Correlation.2.RT-qPCR was used to detect the expression of MIR31 HG in ovarian normal epithelial cell line IOSE80 and ovarian cancer SKOV3 and HO-8910 cell lines.3.CCK8 assay,flow cytometry,Transwell assay were used to study the function of MIR31 HG in human ovarian cancer cells after overexpression or knockdown of MIR31HGThe second part: 1.The bioinformatics software predictive analysis was used to find the MIR31HG-interacting microRNA,as well as its downstream target gene mRNA.RT-qPCR was used to detect the expression of miR-613 in ovarian serous epithelial carcinoma and ovarian normal tissues,and its correlation with MIR31 HG was analyzed.2.RT-qPCR was used to detect the expression of miR-613 in ovarian normal epithelial cell line IOSE80 and ovarian cancer SKOV3 and HO-8910 cell lines.3.After overexpression or knockdown of miR-613,the function of miR-613 in human ovarian cancer cells was studied by CCK8 assay,flow cytometry and Transwell assay.4.The regulatory relationship between MIR31 HG and miR-613 was detected by RT-qPCR.5.The direct regulation relationship between MIR31 HG and miR-613 was detected by luciferase reporter gene assay.6.Immunohistochemistry was used to detect the expression of TMSB4 X in ovarian serous epithelial carcinoma and ovarian normal tissues.7.RT-qPCR was used to detect the expression of TMSB4 X in ovarian normal epithelial cell line IOSE80 and ovarian cancer SKOV3 and HO-8910 cell lines.8.The direct regulation relationship between miR-613 and TMSB4 X was detected by luciferase reporter gene assay.9.Western Blot was used to detect the protein level of TMSB4 X and the regulation of TMSB4 X was verified after transfection of shMIR31 HG,pcDNA3.1-MIR31 HG and miR-613 mimics,inhibitor.Results: The first part: 1.MIR31 HG expression in ovarian serous epithelial cancer tissue increased significantly and associated with ovarian cancer FIGO stage and lymph node metastasis.MIR31 HG mainly expressed in cytoplasm.2.The expression of MIR31 HG in ovarian cancer cell lines SKOV3 and HO-8910 was significantly higher than that in ovarian normal epithelial cell line IOSE80.3.After overexpression of MIR31 HG,SKOV3 and HO-8910 cells showed enhanced proliferation and invasion,and decreased apoptosis.After knocking down MIR31 HG,SKOV3 and HO-8910 cells showed opposite trends.The second part: 1.The expression of miR-613 in ovarian serous epithelial carcinoma tissues was significantly lower than that in normal ovarian tissues and negatively correlated with MIR31 HG.2.The expression of miR-613 in ovarian cancer cell lines SKOV3 and HO-8910 was significantly lower than that in ovarian normal epithelial cell line IOSE80.3.After overexpression of miR-613,SKOV3 and HO-8910 cells had decreased proliferation and invasion,and apoptosis increased.After knocking down miR-613,SKOV3 and HO-8910 cells showed opposite trends.4.MIR31 HG and miR-613 can negatively regulate each other's expression levels.5.The luciferase reporter gene assay showed a direct regulatory relationship between MIR31 HG and miR-613.6.TMSB4 X is highly expressed in ovarian serous epithelial carcinoma tissues.The expression of TMSB4 X in ovarian cancer cell lines SKOV3 and HO-8910 was significantly higher than that in ovarian normal epithelial cell line IOSE80.8.The luciferase reporter gene assay showed a direct regulation relationship between miR-613 and TMSB4 X.9.MIR31 HG and miR-613 can jointly regulate the expression of TMSB4 X,in ovarian cancer.Conclusion: The first part: 1.The expression level of LncRNA MIR31 HG in serous epithelial ovarian cancer tissues is higher than that of normal tissues;2.The high expression of MIR31 HG is related to FIGO stage and lymph node metastasis of ovarian cancer;3.MIR31 HG promotes proliferation and invasion of ovarian cancer cells,and inhibits their apoptosis.The second part: 1.miR-613 expression is low in ovarian serous epithelial carcinoma tissues and shows a significant negative correlation with the expression of MIR31HG;2.miR-613 inhibits proliferation,invasion and promotes apoptosis of ovarian cancer cells;3.TMSB4 X is highly expressed in ovarian serous epithelial carcinoma tissues and cells.4.MIR31 HG as a ceRNA reduced the expression level of miR-613,and then regulated the expression of the target gene TMSB4 X,thereby affecting the biological behavior of ovarian cancer cells.