LncRNA RUNX1-IT1 is Downregulated in Endometrial Cancer and Binds to miR-21 Precursor to Suppress Its Maturation

Minglin Liang, Hongbo Wang, Cong Liu, Tao Lei, Jie Min Department of Obstetrics and Gynecology, Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology, Wuhan City, Hubei Province 430022, People’s Republic of ChinaCorrespondence: Jie MinDepartment of Obstetrics and Gynecology, Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province, People’s Republic of ChinaEmail minjieobstetrics@163.comBackground: RUNX1-IT1 suppresses colorectal cancer and liver cancer, while its role in other cancers is unknown. This study was performed to investigate the role of RUNX1-IT1 in endometrial cancer (EC).Methods: EC and paired non-tumor tissues were collected from 62 EC patients, and the expression of RUNX1-IT1, mature miR-21 and miR-21 precursor in these tissue samples were determined by RT-qPCR. Correlations were analyzed by linear regression. Overexpression of RUNX1-IT1 was achieved in EC cells and the expression of mature miR-21 and miR-21 precursor were analyzed by RT-qPCR. CCK-8 assay was used for cell proliferation analysis.Results: We found that RUNX1-IT1 was downregulated in EC and inversely correlated with mature miR-21 but not miR-21 precursor. RUNX1-IT1 was predicted to bind with miR-21 precursor. The interaction between them was verified by dual-luciferase activity assay and RNA pull-down assay. In EC cells, overexpression of RUNX1-IT1 downregulated mature miR-21, but not miR-21 precursor. Overexpression of RUNX1-IT1 suppressed the role of miR-21 in increasing cell proliferation.Conclusion: RUNX1-IT1 is downregulated in EC and inhibits cancer cell proliferation by suppressing the maturation of miR-21.Keywords: endometrial cancer, RUNX1-IT1, miR-21, precursor, proliferation