Upregulation of miR-146a by YY1 depletion correlates with delayed progression of prostate cancer

Int J Oncol. 2017 Feb;50(2):421-431. doi: 10.3892/ijo.2017.3840. Epub 2017 Jan 5.

Abstract

Previously published studies explained that the excessive expression of miR-146a influences the prostate cancer (PCa) cells in terms of apoptosis, progression, and viability. Although miR-146a acts as a tumor suppressor, current knowledge on the molecular mechanisms that controls its expression in PCa is limited. In this study, gene set enrichment analysis (GSEA) showed negatively enriched expression of miR-146a target gene sets and positively enriched expression of gene sets suppressed by the enhancer of zeste homolog 2 (EZH2) after YY1 depletion in PCa cells. The current results demonstrated that the miR-146a levels in PCa tissues with high Gleason scores (>7) are significantly lower than those in PCa tissues with low Gleason scores (≤7), which were initially observed in the clinical specimens. An inverse relationship between YY1 and miR-146a expression was also observed. Experiments indicated the decrease in cell viability, proliferation, and promoting apoptosis after YY1 depletion, while through inhibiting miR-146a could alleviate the negative effect brought by YY1 depletion. We detected the reversed adjustment of YY1 to accommodate miR-146a transcriptions. On the basis of YY1 depletion, we determined that the expression of miR-146a increased after EZH2 knockdown. We validated the combination of YY1 and its interaction with EZH2 at the miR-146a promoter binding site, thereby prohibiting the transcriptional activity of miR-146a in PCa cells. Our results suggested that YY1 depletion repressed PCa cell viability and proliferation and induced apoptosis at least in a miR-146a-assisted manner.

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Blotting, Western
  • Cell Proliferation / genetics
  • Cell Survival / genetics
  • Chromatin Immunoprecipitation
  • Disease Progression
  • Gene Expression Regulation, Neoplastic / genetics*
  • Heterografts
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization
  • Male
  • Mice
  • Mice, Inbred BALB C
  • MicroRNAs / biosynthesis*
  • MicroRNAs / genetics
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / pathology*
  • Real-Time Polymerase Chain Reaction
  • Up-Regulation
  • YY1 Transcription Factor / genetics
  • YY1 Transcription Factor / metabolism*

Substances

  • MIRN146 microRNA, human
  • MicroRNAs
  • YY1 Transcription Factor
  • YY1 protein, human