Increased expression of miR-1179 inhibits breast cancer cell metastasis by modulating Notch signaling pathway and correlates with favorable prognosis

W.-J. Li, X.-X. Xie, J. Bai, C. Wang, L. Zhao, D.-Q. Jiang

Department of Breast Surgery, Cancer Hospital of China Medical University, Liaoning Cancer Hospital and Institute, Shenyang, Liaoning, China. daqing26@126.com

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• Oncology

OBJECTIVE: MicroRNAs (miRNAs) play a key role in the regulation of gene expression. In this study, we aimed to identify the clinical values of miR-1179 and to investigate the potential molecular mechanisms in breast cancer (BC).

MATERIALS AND METHODS: RT-PCR was used to detect the expression levels of miR-1179 in both BC tissues and cell lines. We analyzed the association between the miR-1179 levels and clinicopathological factors and patient prognosis. The proliferation ability of miR-1179 on BC cells was assessed by MTT and colony formation assay. The role of miR-1179 in BC cells migration and invasion was measured by transwell assays. Western blot analysis was used to quantify the expression of the molecular biomarkers of the Notch signaling pathway.

RESULTS: Our results showed that miR-1179 expression was frequently downregulated in BC tissues and cell lines. Clinicopathologic analysis revealed that low miR-1179 expression is correlated with lymph node metastasis, advanced clinical stage and shorter overall survival. Multivariable Cox proportional hazards regression analysis suggested that increased miR-1179 expression was an independent prognostic factor of overall survival in BC patients. Gain-of-function assay indicated that the overexpression of miR-1179 significantly suppressed BC cells proliferation, migration and invasion. Mechanistically, miR-1179 up-regulation inhibited the expression of Notch 1, Notch 4 and Hes1, indicating that miR-1179 could suppress the activation of the Notch signaling pathway.

CONCLUSIONS: We showed that miR-1179 was a tumor suppressor that may serve as a novel potential prognostic biomarker or molecular therapeutic target for BC.

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