Transcriptional regulation of miR-196b by ETS2 in gastric cancer cells

Carcinogenesis. 2012 Apr;33(4):760-9. doi: 10.1093/carcin/bgs023. Epub 2012 Jan 31.

Abstract

E26 transformation-specific sequence (ETS)-2 is a transcriptional modulator located on chromosome 21, alterations in its expression have been implicated with a reduced incidence of solid tumors in Down syndrome patients. MicroRNAs (miRNAs) are thought to participate in diverse biological functions; however, the regulation of miRNAs is not well characterized. Recently, we reported that miR-196b is highly expressed in gastric cancers. Herein, we demonstrate that miR-196b expression was significantly repressed by ETS2 during gastric cancer oncogenesis. We demonstrate that knockdown of endogenous ETS2 expression increases miR-196b expression. A genomic region between -751 and -824 bp upstream of the miR-196b transcriptional start site was found to be critical for the repression activity. This putative regulatory promoter region contains three potential ETS2-binding motifs. Mutations within the ETS2 binding sites blocked the repression activity of ETS2. Furthermore, knockdown of ETS2 or overexpression of miR-196b significantly induced migration and invasion in gastric cancer cells. In addition, alterations in ETS2 and miR-196b expression in gastric cancer cell lines affected the expression of epithelial-mesenchymal transition-related genes. The levels of vimentin, matrix metalloproteinase (MMP)-2 and MMP9 were drastically induced, but levels of E-cadherin were decreased in shETS2- or miR-196b-transfected cells. Our data indicate that ETS2 plays a key role in controlling the expression of miR-196b, and miR-196b may mediate the tumor suppressor effects of ETS2. We demonstrated that miR-196b was transcriptionally regulated by ETS2 and there was an inverse expression profile between miR-196b and ETS2 in clinical samples. This finding could be beneficial for the development of effective cancer diagnostic and alternative therapeutic strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Line, Tumor
  • Chromatin Immunoprecipitation
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • MicroRNAs / genetics*
  • Molecular Sequence Data
  • Promoter Regions, Genetic
  • Proto-Oncogene Protein c-ets-2 / physiology*
  • RNA Interference
  • Sequence Homology, Nucleic Acid
  • Stomach Neoplasms / genetics*
  • Stomach Neoplasms / pathology
  • Transcription, Genetic*

Substances

  • ETS2 protein, human
  • MIRN196 microRNA, human
  • MicroRNAs
  • Proto-Oncogene Protein c-ets-2