Analysis of MiR-195 and MiR-497 expression, regulation and role in breast cancer

Clin Cancer Res. 2011 Apr 1;17(7):1722-30. doi: 10.1158/1078-0432.CCR-10-1800. Epub 2011 Feb 24.


Purpose: To investigate expression, regulation, potential role and targets of miR-195 and miR-497 in breast cancer.

Experimental design: The expression patterns of miR-195 and miR-497 were initially examined in breast cancer tissues and cell lines by Northern blotting and quantitative real-time PCR. Combined bisulfite restriction analysis and bisulfite sequencing were carried out to study the DNA methylation status of miR-195 and miR-497 genes. Breast cancer cells stably expressing miR-195 and miR-497 were established to study their role and targets. Finally, normal, fibroadenoma and breast cancer tissues were employed to analyze the correlation between miR-195/497 levels and malignant stages of breast tumor tissues.

Results: MiR-195 and miR-497 were significantly downregulated in breast cancer. The methylation state of CpG islands upstream of the miR-195/497 gene was found to be responsible for the downregulation of both miRNAs. Forced expression of miR-195 or miR-497 suppressed breast cancer cell proliferation and invasion. Raf-1 and Ccnd1 were identified as novel direct targets of miR-195 and miR-497. miR-195/497 expression levels in clinical specimens were found to be correlated inversely with malignancy of breast cancer.

Conclusions: Our data imply that both miR-195 and miR-497 play important inhibitory roles in breast cancer malignancy and may be the potential therapeutic and diagnostic targets.

Publication types

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

MeSH terms

  • 3' Untranslated Regions
  • Base Sequence
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Cell Movement
  • Cell Proliferation
  • CpG Islands
  • Cyclin D1 / metabolism
  • DNA Methylation
  • Down-Regulation
  • Female
  • Gene Silencing
  • Genes, Reporter
  • Humans
  • Luciferases, Renilla / biosynthesis
  • Luciferases, Renilla / genetics
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Neoplasm Invasiveness
  • Proto-Oncogene Proteins c-raf / metabolism
  • Restriction Mapping


  • 3' Untranslated Regions
  • CCND1 protein, human
  • MIRN195 microRNA, human
  • MIRN497 microRNA, human
  • MicroRNAs
  • Cyclin D1
  • Luciferases, Renilla
  • Proto-Oncogene Proteins c-raf