Activation of antioxidant/electrophile-responsive elements in IMR-32 human neuroblastoma cells

Arch Biochem Biophys. 1999 Mar 1;363(1):98-106. doi: 10.1006/abbi.1998.1046.


The present investigation demonstrates distinct patterns of activation for antioxidant/electrophile-responsive elements (ARE/EpREs) in cells of neuronal versus hepatic origin suggesting the possibility of cell-/tissue-specific signaling pathways and/or transcription factors required for ARE/EpRE activation. The ARE/EpRE is a cis-acting regulatory element found in 5'-flanking regions of numerous genes including NAD(P)H:quinone oxidoreductase (QR) and glutathione S-transferases. Insomuch as ARE/EpRE activation has been studied primarily in hepatoma cell lines there is little information on how these responsive elements and corresponding genes are regulated in brain. ARE/EpRE-reporter constructs were transiently transfected into IMR-32 human neuroblastoma cells. Activation of ARE/EpRE sequences by tert-butylhydroquinone (tBHQ), a redox-cycling compound, in IMR-32 cells (20- to 30-fold) is dramatically different from the minimal response seen in HepG2 human hepatoma cells (2- to 3-fold). beta-napthoflavone, an ARE/EpRE inducer in HepG2 cells, as well as the oxidants hydrogen peroxide and tert-butyl hydroperoxide did not induce the ARE/EpRE in IMR-32 cells. In addition, we show that the core sequence containing a complete 5' palindrome is necessary for maximal activation of the ARE/EpRE in IMR-32 cells. Mutations within this palindromic sequence decrease basal level expression and block induction by tBHQ but not phorbol 12-myristate 13-acetate. Furthermore, activation of the hQR-ARE/EpRE by tBHQ correlates with induction of endogenous QR activity in IMR-32 neuroblastoma cells (15-fold). Thus, elucidating the mechanism of ARE/EpRE activation in this human neuroblastoma cell line may identify unknown transcription factors or signal transduction cascades regulating ARE/EpRE-driven gene expression.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antioxidants / metabolism*
  • Butylated Hydroxyanisole / pharmacology
  • Dose-Response Relationship, Drug
  • Down-Regulation / drug effects
  • Down-Regulation / genetics
  • Enzyme Induction / drug effects
  • Gene Expression Regulation, Neoplastic / drug effects
  • Genes, Reporter / drug effects
  • Humans
  • Hydroquinones / pharmacology
  • NAD(P)H Dehydrogenase (Quinone) / genetics
  • NAD(P)H Dehydrogenase (Quinone) / metabolism
  • Neuroblastoma
  • Neurons / metabolism*
  • Protein Kinase C / metabolism
  • Regulatory Sequences, Nucleic Acid / genetics
  • Signal Transduction / physiology
  • Tetradecanoylphorbol Acetate / pharmacology
  • Transcriptional Activation / drug effects
  • Tumor Cells, Cultured


  • Antioxidants
  • Hydroquinones
  • Butylated Hydroxyanisole
  • 2-tert-butylhydroquinone
  • NAD(P)H Dehydrogenase (Quinone)
  • Protein Kinase C
  • Tetradecanoylphorbol Acetate