MicroRNA regulation of DNA repair gene expression in 4-aminobiphenyl-treated HepG2 cells

Toxicology. 2014 Aug 1:322:69-77. doi: 10.1016/j.tox.2014.05.003. Epub 2014 May 23.

Abstract

We examined the role of miRNAs in DNA damage response in HepG2 cells following exposure to 4-aminobiphenyl (4-ABP). The arylamine 4-ABP is a human carcinogen. Using the Comet assay, we showed that 4-ABP (18.75-300μM) induces DNA damage in HepG2 cells after 24h. DNA damage signaling pathway-based PCR arrays were used to investigate expression changes in genes involved in DNA damage response. Results showed down-regulation of 16 DNA repair-related genes in 4-ABP-treated cells. Among them, the expression of selected six genes (UNG, LIG1, EXO1, XRCC2, PCNA, and FANCG) from different DNA repair pathways was decreased with quantitative real-time PCR (qRT-PCR). In parallel, using the miRNA array, we reported that the expression of 27 miRNAs in 4-ABP-treated cells was at least 3-fold higher than that in the control group. Of these differential 27 miRNAs, the most significant expression of miRNA-513a-5p and miRNA-630 was further validated by qRT-PCR, and was predicted to be implicated in the deregulation of FANCG and RAD18 genes, respectively, via bioinformatic analysis. Both FANCG and RAD18 proteins were found to be down-regulated in 4-ABP-treated cells. In addition, overexpression and knockdown of miRNA-513a-5p and miRNA-630 reduced and increased the expression of FANCG and RAD18 proteins, respectively. Based on the above results, we indicated that miRNA-513a-5p and miRNA-630 could play a role in the suppression of DNA repair genes, and eventually lead to DNA damage.

Keywords: DNA damage; DNA repair; miRNA-513a-5p; miRNA-630.

MeSH terms

  • Aminobiphenyl Compounds / toxicity*
  • Blotting, Western
  • Carcinogens / toxicity*
  • Cell Survival / drug effects
  • Comet Assay
  • Culture Media
  • DNA Damage
  • DNA Repair / genetics*
  • Gene Expression / drug effects*
  • Humans
  • In Situ Hybridization
  • RNA / biosynthesis
  • RNA / isolation & purification
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / physiology*
  • Real-Time Polymerase Chain Reaction

Substances

  • Aminobiphenyl Compounds
  • Carcinogens
  • Culture Media
  • RNA, Messenger
  • 4-biphenylamine
  • RNA