miR-340 and ZEB1 negative feedback loop regulates TGF-β- mediated breast cancer progression

Oncotarget. 2016 May 3;7(18):26016-26. doi: 10.18632/oncotarget.8421.


MicroRNAs act as key regulators in carcinogenesis and progression in various cancers. In present study, we explored the role of miR-340 in the breast cancer progression. Our results showed that overexpression of miR-340 inhibits breast cancer cell proliferation and invasion, whereas depletion of miR-340 promotes breast cancer progression. Molecularly, ZEB1 was identified as a target gene of miR-340 and miR-340 suppressed the expression of ZEB1 by directly binding to the 3'-UTR of ZEB1. Furthermore, ZEB1 transcriptionally suppresses miR-340 expression. The negative feedback loop regulated TGF-β-mediated breast cancer progression. In conclusion, our data suggested that miR-340 acted as a tumor suppressor in breast cancer progression.

Keywords: EMT; TGF-β; ZEB1; breast cancer; miR-340.

MeSH terms

  • Apoptosis
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism*
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology*
  • Cell Adhesion
  • Cell Movement
  • Cell Proliferation
  • Disease Progression
  • Epithelial-Mesenchymal Transition
  • Feedback, Physiological*
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • MicroRNAs / genetics*
  • Transforming Growth Factor beta / metabolism*
  • Tumor Cells, Cultured
  • Zinc Finger E-box-Binding Homeobox 1 / genetics
  • Zinc Finger E-box-Binding Homeobox 1 / metabolism*


  • Biomarkers, Tumor
  • MIRN340 microRNA, human
  • MicroRNAs
  • Transforming Growth Factor beta
  • ZEB1 protein, human
  • Zinc Finger E-box-Binding Homeobox 1