Micro-RNA-632 downregulates DNAJB6 in breast cancer

Lab Invest. 2012 Sep;92(9):1310-7. doi: 10.1038/labinvest.2012.87. Epub 2012 Jun 18.


DNAJB6 is a constitutively expressed member of the HSP40 family. It has been described as a negative regulator of breast tumor progression and a regulator of epithelial phenotype. Expression of DNAJB6 is reported to be compromised with tumor progression. However, factors responsible for its downregulation are still undefined. We used a knowledge-based screen for identifying miRNAs capable of targeting DNAJB6. In this work, we present our findings that hsa-miR-632 (miR-632) targets the coding region of DNAJB6. Invasive and metastatic breast cancer cells express high levels of miR-632 compared with mammary epithelial cells. Analysis of RNA from breast tumor specimens reveals inverse expression patterns of DNAJB6 transcript and miR-632. In response to exogenous miR-632 expression, DNAJB6 protein levels are downregulated and the resultant cell population shows significantly increased invasive ability. Silencing endogenous miR-632 abrogates invasive ability of breast cancer cells and promotes epithelial like characteristics noted by E-cadherin expression with concomitant decrease in mesenchymal markers such as Zeb2 and Slug. Thus, miR-632 is a potentially important epigenetic regulator of DNAJB6, which contributes to the downregulation of DNAJB6 and plays a supportive role in malignant progression.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Binding Sites
  • Blotting, Western
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • DNA Primers
  • Down-Regulation*
  • Female
  • HSP40 Heat-Shock Proteins / metabolism*
  • Humans
  • MicroRNAs / physiology*
  • Molecular Chaperones / metabolism*
  • Nerve Tissue Proteins / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction


  • DNA Primers
  • DNAJB6 protein, human
  • HSP40 Heat-Shock Proteins
  • MIRN632 microRNA, human
  • MicroRNAs
  • Molecular Chaperones
  • Nerve Tissue Proteins