Mecp2-mediated Epigenetic Silencing of miR-137 Contributes to Colorectal Adenoma-Carcinoma Sequence and Tumor Progression via Relieving the Suppression of c-Met

Sci Rep. 2017 Mar 14:7:44543. doi: 10.1038/srep44543.

Abstract

The molecular mechanisms underlying colorectal cancer (CRC) development remain elusive. In this study, we examined the miRNA and mRNA expressions in the adenoma-carcinoma sequence (ACS), a critical neoplastic progression in CRC development. We found that miR-137 was down-regulated in all adenoma and carcinoma tissues. Low miR-137 levels were correlated negatively with tumor progression and metastasis. Then we identified the inhibition effect of the miR-137 in CRC development, both in CRC cell lines and mouse models. MiR-137 was shown to control CRC cell proliferation, colony formation, migration and invasion and to control tumor growth and metastasis. We further confirmed the negative association between miR-137 and c-Met expression and thus validated this important oncogene as the target of miR-137 in CRC. In addition, we found a DNA methyl-CpG-binding protein, Mecp2, was up-regulated in ACS tissues via mRNA sequencing. Further experiment showed that miR-137 expression in CRC was subjected to epigenetic regulation mediated by Mecp2. We also confirmed c-Met expression can be up-regulated by silencing of miR-137 and suppressed by coexpression of Mecp2 and miR-137. These findings highlight the critical role of miR-137-c-Met nexus in CRC development and reveal Mecp2-regulated epigenetic silence causes the downregulation of miR-137 in colorectal adenoma and carcinoma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoma / genetics
  • Adenoma / pathology
  • Animals
  • Carcinoma / genetics
  • Carcinoma / pathology
  • Cell Movement / genetics
  • Cell Proliferation / genetics
  • Colorectal Neoplasms / genetics*
  • Colorectal Neoplasms / pathology
  • Epigenesis, Genetic
  • Gene Expression Regulation, Neoplastic / genetics
  • HCT116 Cells
  • Humans
  • Methyl-CpG-Binding Protein 2 / genetics*
  • Mice
  • MicroRNAs / antagonists & inhibitors
  • MicroRNAs / genetics*
  • Neoplasm Invasiveness / genetics
  • Neoplasm Invasiveness / pathology
  • Neoplasm Metastasis
  • Proto-Oncogene Proteins c-met / genetics*
  • Xenograft Model Antitumor Assays

Substances

  • MECP2 protein, human
  • MIRN137 microRNA, human
  • Methyl-CpG-Binding Protein 2
  • MicroRNAs
  • Proto-Oncogene Proteins c-met