MiR-181a-5p facilitates proliferation, invasion, and glycolysis of breast cancer through NDRG2-mediated activation of PTEN/AKT pathway

Dysregulation of microRNAs (miRNAs) is associated with the occurrence and development of breast cancer. In this research, we explored the involvement of miR-181a-5p in the progression of breast cancer and investigated potential molecular mechanisms. Firstly, the miR-181a-5p and N-myc downstream-regulated gene (NDRG) 2 expression was detected by real-time quantitative polymerase chain reaction. Cellular processes were assessed using Cell Counting Kit 8, Bromodeoxyuridine, colony formation and transwell assays. HK2, PKM2 and LDHA activities were assessed by ELISA. The combination between miR-181a-5p was assessed by dual-luciferase reporter assay and RNA pull-down assay. The results indicated that miR-181a-5p levels were upregulated and NDRG2 levels were downregulated in breast cancer, leading to poor prognosis. Silencing of miR-181a-5p inhibited cell proliferation, invasion, glycolysis, and xenograft tumor growth, while enhanced miR-181a-5p got the opposite results. Furthermore, NDRG2 acts as a target of miR-181a-5p. Knockout of NDRG2 facilitated biological behaviors and meanwhile enhanced phosphorylation (p)-PTEN and p-AKT levels. Rescue experiments showed that restoring NDRG2 abolished the effects caused by miR-181a-5p in breast cancer cells. In conclusion, miR-181a-5p facilitated tumor progression through NDRG2-induced activation of PTEN/AKT signaling pathway of breast cancer, suggesting that focusing on miR-181a-5p may provide new insight for breast cancer therapy. Abbreviations Brdu: Bromodeoxyuridine; CCK-8: Cell Counting Kit-8; miRNA: microRNAs; mut: mutant; RT-qPCR: real-time quantitative polymerase chain reaction; UTR: untranslated region; WT: wild-type