Hypoxia-related MiR-9 Promotes Ovarian Cancer Cell Migration And Invasion

Ovarian cancer is a common malignant tumor of female reproductive system,with the mortality rate ranking the 5th in female malignant tumor and the 1st in female reproductive system malignant tumor.As early symptoms are not obvious,70% of patients have already developed local or distant metastasis at the time of diagnosis.Hypoxia-related micro RNA-9 is a small single-stranded RNA molecule,which has been proved to have significant pro-cancer or anti-cancer effects in other tumors,but its impact on the migration and invasion of ovarian cancer is still unclear.Objective: To explore the effect of hypoxia-related miR-9 on the migration and invasion of ovarian cancer cell.Methods:1.Real-time quantitative reverse transcription-polymerase chain reaction(qRT-PCR)was performed to determine the expression of miR-9 in ovarian cancer tissues and adjacent tissues.2.Human ovarian cancer cells SKOV3 and HO8910 were cultured,transfected with miR-9 mimic or inhibitor,and PI3K inhibitor LY294002 was added to detect migration and invasion of ovarian cancer cells by Transwell assay.QRT-PCR were performed to determine the expression of miR-9 and the mRNA expression of PI3K,AKT,mTOR and GSK3β.3.The effect of miR-9 on tumor growth in vivo was detected by tumorigenesis experiment in nude mice.4.The number of tumor cells in the transplanted tumor of nude mice in each group was detected by HE staining.5.The expressions of PI3K,AKT,mTOR,GSK3β and HIF-1α were detected by immunohistochemistry.Results:1.miR-9 is more highly expressed in ovarian cancer tissues than in adjacent tissues.2.Compared with the NC group,the expression of miR-9 and PI3K,AKT,mTOR and GSK3β mRNA were increased in the cells transfected with miR-9 mimic.Compared with the NC group,the expression of miR-9 and PI3K,AKT,mTOR and GSK3β mRNA were decreased in the cells transfected with miR-9 inhibitor.Transwell assay results showed that the number of migrating and invading cells was significantly increased in ovarian cancer cells transfected with miR-9 analogues,and significantly decreased in ovarian cancer cells transfected with miR-9 inhibitors.The addition of LY294002 reversed the promoting effect of miR-9 analogues on ovarian cancer cell migration and invasion.3.In the tumorigenesis experiment of nude mice,the volume and weight of transplanted tumors in the hypoxic group were significantly larger than those in the normoxic group;In the group of ovarian cancer cells transfected with shRNA-miR-9-5p,the volume and weight of transplanted tumor were significantly reduced compared with the NC group.The size and weight of transplanted tumors in the LY294002 group were smaller than those in the DMSO group.4.The results of HE staining showed that the number of tumor cells in the hypoxia group was more than that in the normoxic group,the number of tumor cells in the shRNA-miR-9-5p group was less than that in the shRNA NC group,and the number of tumor cells in the LY294002 group was less than that in the DMSO group.5.Immunohistochemical results showed that p-PI3K,p-AKT,p-mTOR,p-GSK3β,HIF-1α protein expression was higher in hypoxia group than in normoxic group.The expression of p-PI3K,p-AKT,p-mTOR,p-GSK3β and HIF-1α in shRNAmiR-9-5P group was lower than that in shRNA NC group.The expression of pPI3K,p-Akt,p-mTOR,p-GSK3β and HIF-1α in LY294002 group was lower than that in DMSO group.Conclusion: The expression of miR-9 is upregulated in ovarian cancer and promotes ovarian cancer cell migration and invasion.Knockdown of miR-9 reduces the malignant phenotype of ovarian cancer.The effect of miR-9 on ovarian cancer migration and invasion may be achieved by activating PI3K/AKT/mTOR/GSK3β.