MicroRNA-935 mediates the regulatory effect of lncRNA KCNQ1OT1 on tumor progression of breast cancer

Background: The biological function of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have received increasing attention in the pathogenesis of various malignancies. This study aimed to evaluate the functional role and clinical significance of the KCNQ1OT1/miR-935 axis in breast cancer (BCa) progression. Methods Expression of KCNQ1OT1 and miR-935 was estimated using quantitative real-time PCR (qRT-PCR). The interaction between KCNQ1OT1 and miR-935 was confirmed by luciferase reporter assay. BCa cell proliferation, migration and invasion were evaluated using CCK-8 and Transwell assays. The clinical significance of the KCNQ1OT1/miR-935 axis in BCa diagnosis was examined by ROC analysis. Results The expression of KCNQ1OT1 was significantly elevated, but the miR-935 expression was decreased in BCa cells (all P < 0.01). KCNQ1OT1 could directly bind to miR-935, leading to the decreased miR-935 expression in BCa cells (P < 0.001). The overexpression of miR-935 could inhibit BCa cell proliferation, migration and invasion, and remarkably reversed the regulatory effect of KCNQ1OT1 on BCa cell biological processes (all P < 0.05). Serum KCNQ1OT1 levels were negatively correlated with miR-935 levels in BCa patients. The aberrant expression of KCNQ1OT1 and miR-935 had relatively high diagnostic accuracy for the screening of BCa patients. Conclusion In conclusion, miR-935 expression is downregulated in BCa cells, which can be inhibited by KCNQ1OT1 and mediates the promoting effect of KCNQ1OT1 on BCa tumor progression in vivo. Serum reduced expression of miR-935 may serve as a diagnostic biomarker of BCa, and the KCNQ1OT1/miR-935 axis provides potential therapeutic targets for BCa treatment.