microRNA-9 suppresses the proliferation, invasion and metastasis of gastric cancer cells through targeting cyclin D1 and Ets1

PLoS One. 2013;8(1):e55719. doi: 10.1371/journal.pone.0055719. Epub 2013 Jan 31.

Abstract

Recent evidence shows that altered microRNA-9 (miR-9) expression is implicated in the progression of gastric cancer. However, the exact roles and underlying mechanisms of miR-9 in the proliferation, invasion and metastasis of gastric cancer still remain unknown. In this study, miR-9 was found to be down-regulated and inversely correlated with the expression of cyclin D1 and v-ets erythroblastosis virus E26 oncogene homolog 1 (Ets1) in gastric cancer tissues and cell lines. Bioinformatics analysis revealed the putative miR-9 binding sites in the 3'-untranslated regions (3'-UTR) of cyclin D1 and Ets1 mRNA. Ectopic expression or knockdown of miR-9 resulted in responsively altered expression of cyclin D1, Ets1 and their downstream targets phosphorylated retinoblastoma and matrix metalloproteinase 9 in cultured gastric cancer cell lines SGC-7901 and AGS. In the luciferase reporter system, miR-9 directly targeted the 3'-UTR of cyclin D1 and Ets1, and these effects were abolished by mutating the miR-9 binding sites. Over-expression of miR-9 suppressed the proliferation, invasion, and metastasis of SGC-7901 and AGS cells in vitro and in vivo. Restoration of miR-9-mediated down-regulation of cyclin D1 and Ets1 by transient transfection, rescued the cancer cells from decrease in proliferation, migration and invasion. Furthermore, anti-miR-9 inhibitor promoted the proliferation, migration and invasion of gastric cancer cells, while knocking down of cyclin D1 or Ets1 partially phenocopied the effects of miR-9 over-expression. These data indicate that miR-9 suppresses the expression of cyclin D1 and Ets1 via the binding sites in their 3'-UTR, thus inhibiting the proliferation, invasion and metastasis of gastric cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Cell Proliferation
  • Cyclin D1 / genetics*
  • Gene Expression Regulation, Neoplastic
  • Humans
  • MicroRNAs / chemistry
  • MicroRNAs / genetics*
  • Neoplasm Invasiveness
  • Neoplasm Metastasis
  • Proto-Oncogene Protein c-ets-1 / genetics*
  • RNA Interference
  • RNA Processing, Post-Transcriptional
  • Stomach Neoplasms / genetics*
  • Stomach Neoplasms / pathology*
  • Tumor Burden / genetics

Substances

  • MIRN92 microRNA, human
  • MicroRNAs
  • Proto-Oncogene Protein c-ets-1
  • Cyclin D1

Grants and funding

Supported by the National Natural Science Foundation of China (No. 30600278, No. 30772359, No. 81071997, No. 81072073, No. 81272779), Program for New Century Excellent Talents in University (NCET-06-0641), Scientific Research Foundation for the Returned Overseas Chinese Scholars (2008-889), and Fundamental Research Funds for the Central Universities (2012QN224). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.