Nickel compounds induce apoptosis in human bronchial epithelial Beas-2B cells by activation of c-Myc through ERK pathway

Toxicol Appl Pharmacol. 2009 Mar 1;235(2):191-8. doi: 10.1016/j.taap.2008.12.005. Epub 2008 Dec 16.

Abstract

Nickel compounds are carcinogenic to humans and have been shown to alter epigenetic homeostasis. The c-Myc protein controls 15% of human genes and it has been shown that fluctuations of c-Myc protein alter global epigenetic marks. Therefore, the regulation of c-Myc by nickel ions in immortalized but not tumorigenic human bronchial epithelial Beas-2B cells was examined in this study. It was found that c-Myc protein expression was increased by nickel ions in non-tumorigenic Beas-2B and human keratinocyte HaCaT cells. The results also indicated that nickel ions induced apoptosis in Beas-2B cells. Knockout of c-Myc and its restoration in a rat cell system confirmed the essential role of c-Myc in nickel ion-induced apoptosis. Further studies in Beas-2B cells showed that nickel ion increased the c-Myc mRNA level and c-Myc promoter activity, but did not increase c-Myc mRNA and protein stability. Moreover, nickel ion upregulated c-Myc in Beas-2B cells through the MEK/ERK pathway. Collectively, the results demonstrate that c-Myc induction by nickel ions occurs via an ERK-dependent pathway and plays a crucial role in nickel-induced apoptosis in Beas-2B cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Apoptosis / drug effects*
  • Blotting, Western
  • Cell Line
  • Epithelial Cells / drug effects*
  • Extracellular Signal-Regulated MAP Kinases / physiology*
  • Flow Cytometry
  • Genes, Reporter
  • Humans
  • Keratinocytes / drug effects
  • Luciferases / metabolism
  • Nickel / toxicity*
  • Proto-Oncogene Proteins c-myc / physiology*
  • RNA / biosynthesis
  • RNA / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / drug effects
  • ras Proteins / genetics
  • ras Proteins / physiology

Substances

  • Proto-Oncogene Proteins c-myc
  • RNA
  • Nickel
  • Luciferases
  • Extracellular Signal-Regulated MAP Kinases
  • ras Proteins