An integrated expression profiling reveals target genes of TGF-β and TNF-α possibly mediated by microRNAs in lung cancer cells

PLoS One. 2013;8(2):e56587. doi: 10.1371/journal.pone.0056587. Epub 2013 Feb 20.

Abstract

EMT (epithelial-mesenchymal transition) is crucial for cancer cells to acquire invasive phenotypes. In A549 lung adenocarcinoma cells, TGF-β elicited EMT in Smad-dependent manner and TNF-α accelerated this process, as confirmed by cell morphology, expression of EMT markers, capacity of gelatin lysis and cell invasion. TNF-α stimulated the phosphorylation of Smad2 linker region, and this effect was attenuated by inhibiting MEK or JNK pathway. Comprehensive expression analysis unraveled genes differentially regulated by TGF-β and TNF-α, such as cytokines, chemokines, growth factors and ECM (extracellular matrices), suggesting the drastic change in autocrine/paracrine signals as well as cell-to-ECM interactions. Integrated analysis of microRNA signature enabled us to identify a subset of genes, potentially regulated by microRNAs. Among them, we confirmed TGF-β-mediated induction of miR-23a in lung epithelial cell lines, target genes of which were further identified by gene expression profiling. Combined with in silico approaches, we determined HMGN2 as a downstream target of miR-23a. These findings provide a line of evidence that the effects of TGF-β and TNF-α were partially mediated by microRNAs, and shed light on the complexity of molecular events elicited by TGF-β and TNF-α.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / genetics*
  • Adenocarcinoma / metabolism
  • Adenocarcinoma / pathology
  • Adenocarcinoma of Lung
  • Cell Line, Tumor
  • Computer Simulation
  • Epithelial-Mesenchymal Transition / genetics
  • Gene Expression Regulation, Neoplastic
  • HMGN2 Protein / genetics
  • HMGN2 Protein / metabolism
  • Humans
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Signal Transduction
  • Smad2 Protein / metabolism
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / metabolism*
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism*

Substances

  • HMGN2 Protein
  • MIRN23a microRNA, human
  • MicroRNAs
  • SMAD2 protein, human
  • Smad2 Protein
  • Transforming Growth Factor beta
  • Tumor Necrosis Factor-alpha

Grant support

This work was supported by KAKENHI (Grants-in-Aid for Scientific Research) from the Ministry of Education, Culture, Sports, Science, and Technology and grants from the Ministry of Health, Labour and Welfare of Japan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.