LincRNA-ROR Induces Epithelial-to-mesenchymal Transition In High-grade Ovarian Serous Cancer By Increasing Wnt/β-catenin Signaling

Objective: To investigate the expression of long intergenic non-coding RNA-ROR(Linc-ROR)in high-grade ovarian serous cancer,and to explore the relationship between Linc-ROR expression and biological function of high-grade ovarian serous cancer cells,and to analyze the effects of Linc-ROR on epithelial-to-mesenchymal transition(EMT)in high-grade ovarian serous cancer cells by increasing Wnt/β-catenin signaling pathway.Methods:(1)We collected 34 high-grade ovarian serous cancer tissue samples,20 normal ovarian tissue samples and 20 normal fallopian tube tissue samples between June 2014 and February 2016.Real-time reverse transcription(q RT)-PCR was used to detect the Linc-ROR expression in different samples.The relationship between Linc-ROR expression level and ovarian cancer International Federation of Gynecology and Obstetrics(FIGO)stage,lymph node metastasis was analyzed.(2)Constructing Linc-ROR small interference RNA(si RNA)and p IRES2-EGFP-Linc-ROR plasmid,then Linc-ROR si RNA and p IRES2-EGFP-Linc-ROR plasmid were transfected into SKOV3 cells separately.Cell proliferation,migration and invasion ability was assessed by cell counting kit-8(CCK-8),wound healing assay and transwell invasion assay.The protein expression of EMT related markers E-cadherin,β-catenin,vimentin and Wnt / β-catenin pathway target gene c-myc was detected by Western blot.(3)Ovarian cancer SKOV3 cells were treated with Lithium chloride(Li Cl),cell proliferation was assessed using CCK-8 assay.The expression of E-cadherin,β-catenin,vimentin and c-myc protein was measured by Western blot.SKOV3 cells were treated with both Li Cl and Linc-ROR si RNA,both Li Cl and Linc-ROR si RNA-control,the expression of E-cadherin,β-catenin,vimentin and c-myc protein was measured by Western blot.Results:(1)The expression level of Linc-ROR m RNA was significantly higher in high-grade ovarian serous cancer than normal ovarian tissues and normal fallopian tube tissues(4.38±2.55,1.49±1.69,1.45±1.57;F=8.62,P<0.01).With the progression of FIGO stages,the expression of Linc-ROR was increased(F=95.702,P<0.01),and it was associated with lymph node metastasis(t=7.397,P<0.01).(2)The expression of Linc-ROR m RNA in Linc-ROR si RNA group cells was significantly lower than that in the Linc-ROR si RNA-NC group(F=26.29,P<0.05).Compared with the negative control si RNA-NC group,the proliferation,migration and invasion ability of SKOV3 cells in si RNA group were significantly decreased(P<0.01),the expression of E-cadherin protein was significantly increased,and the expression of β-catenin,vimentin and c-myc protein was significantly decreased(P<0.01).(3)The expression level of Linc-ROR m RNA in ROR group was significantly higher than that in Vector group(t= 6.304,P<0.01).Compared with the negative control Vector group,the proliferation,migration and invasion ability of SKOV3 cells in ROR group were significantly increased(P<0.01),the expression of E-cadherin protein was significantly decreased,and the expression of β-catenin,vimentin and c-myc protein was significantly increased(P<0.01).(4)The cell proliferation was significantly different in SKOV3 cells treated with different concentration of Li Cl at different times(P<0.05),and the best concentration is 10mmol/L,the optimal time is 24 hours.Added Li Cl to SKOV3 cells induced the decrease of E-cadherin protein expression(P<0.01),the increase of β-catenin,vimentin and c-myc protein expression(P<0.01).Compared with the Li Cl group and Li Cl + si RNA-control group,in Li Cl + Linc-ROR si RNA group,the expression of E-cadherin protein was significantly up-regulated,and the expression of β-catenin,vimentin and c-myc protein was significantly down-regulated(P<0.01).Conclusion: Abnormally expressed Linc-ROR was closely related to the invasion and metastasis of high-grade ovarian serous cancer.High expression of Linc-ROR could induce ovarian cancer cell EMT,which may play a role in regulating Wnt / β-catenin signaling pathway.Linc-ROR may be one of the important molecules in the invasion and metastasis of high-grade ovarian serous cancer.