Down-regulation of miR-126 is associated with colorectal cancer cells proliferation, migration and invasion by targeting IRS-1 via the AKT and ERK1/2 signaling pathways

PLoS One. 2013 Nov 29;8(11):e81203. doi: 10.1371/journal.pone.0081203. eCollection 2013.

Abstract

Background: Colorectal carcinoma (CRC) is one of the leading causes of cancer-related mortality worldwide. MicroRNAs (miRNAs, miRs) play important roles in carcinogenesis. MiR-126 has been shown to be down-regulated in CRC. In this study, we identified the potential effects of miR-126 on some important biological properties of CRC cells and clarified the regulation of insulin receptor substrate 1 (IRS-1) and its possible signaling pathway by miR-126.

Methods: The effect of miR-126 on IRS-1, AKT, and ERK1/2 expression was assessed in the CRC cell lines HT-29 and HCT-116 with a miR-126 mimic or inhibitor to increase or decrease miR-126 expression. Furthermore, the roles of miR-126 in regulation of the biological properties of CRC cells were analyzed with miR-126 mimic or inhibitor-transfected cells. The 3'-untranslated region (3'-UTR) of IRS-1 regulated by miR-126 was analyzed by using a dual-luciferase reporter assay.

Results: We found that IRS-1 is the functional downstream target of miR-126 by directly targeting the 3'-UTR of IRS-1. Endogenous miR-126 and exogenous miR-126 mimic inhibited IRS-1 expression. Furthermore, gain-of-function or loss-of-function studies showed that over-expression of miR-126 down-regulated IRS-1, suppressed AKT and ERK1/2 activation, CRC cells proliferation, migration, invasion, and caused cell cycle arrest, but had no effect on cell apoptosis. Knockdown of miR-126 promoted these processes in HCT-116 cells and promoted AKT and ERK1/2 activation by up-regulating the expression of the IRS-1 protein.

Conclusions: MiR-126 may play roles in regulation of the biological behavior of CRC cells, at least in part, by targeting IRS-1 via AKT and ERK1/2 signaling pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinogenesis
  • Cell Line, Tumor
  • Cell Movement / genetics*
  • Cell Proliferation
  • Colorectal Neoplasms / pathology*
  • Down-Regulation*
  • Enzyme Activation
  • G1 Phase Cell Cycle Checkpoints / genetics
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Insulin Receptor Substrate Proteins / genetics*
  • Insulin Receptor Substrate Proteins / metabolism
  • MAP Kinase Signaling System / genetics*
  • MicroRNAs / genetics*
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Neoplasm Invasiveness
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Resting Phase, Cell Cycle / genetics

Substances

  • Insulin Receptor Substrate Proteins
  • MIRN126 microRNA, human
  • MicroRNAs
  • Proto-Oncogene Proteins c-akt
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3

Grants and funding

This study was supported by Foundation for Distinguished Young Talents in Higher Education of Guangdong, China (grant number LYM11103). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.