miR-206 is down-regulated in breast cancer and inhibits cell proliferation through the up-regulation of cyclinD2

Biochem Biophys Res Commun. 2013 Apr 5;433(2):207-12. doi: 10.1016/j.bbrc.2013.02.084. Epub 2013 Mar 1.


MicroRNAs act as important gene regulators in human genomes, and their aberrant expression is linked to many malignancies. Aberrant expression of miR-206 has been frequently reported in cancer studies; however, the role and mechanism of its function in breast cancer remains unclear. Quantitative real-time PCR was performed to detect the relative expression levels of miR-206 in breast cancer and normal breast tissues. Lower expression of miR-206 in breast cancer tissues was associated with larger tumour size and a more advanced clinical stage. Further in vitro observations showed that the enforced expression of miR-206 in MCF-7 breast cancer cells inhibited cell growth by blocking the G1/S transition and suppressed cell proliferation and colony formation, implying that miR-206 functions as a tumour suppressor in the progression of breast cancer. Interestingly, Luciferase assays first revealed that miR-206 inhibited cyclinD2 expression by targeting two binding sites in the 3'-untranslated region of cyclinD2 mRNA. qRT-PCR and Western blot assays verified that miR-206 reduced cyclinD2 expression at both the mRNA and protein levels. A reverse correlation between miR-206 and cyclinD2 expression was noted in breast cancer tissues. Altogether, our results identify a crucial tumour suppressive role of miR-206 in the progression of breast cancer, at least partly via up-regulation of the expression of cyclinD2, and suggest that miR-206 might be a candidate prognostic predictor or an anticancer therapeutic target for breast cancer patients.

MeSH terms

  • 3' Untranslated Regions
  • Binding Sites
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology*
  • Cell Line, Tumor
  • Cell Proliferation
  • Cyclin D2 / genetics
  • Cyclin D2 / metabolism*
  • Down-Regulation
  • Female
  • G1 Phase / genetics
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • MicroRNAs / genetics*
  • Reference Values
  • S Phase / genetics
  • Up-Regulation


  • 3' Untranslated Regions
  • CCND2 protein, human
  • Cyclin D2
  • MIRN206 microRNA, human
  • MicroRNAs