Induction of cytochrome P450 1A1 in human hepatoma HepG2 cells by 6-nitrochrysene

Ruei Ming Chen, Ming W. Chou, Tzuu-Huei Ueng

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16 Citations (Scopus)


The present study has determined the effects of 6-nitrochrysene (6-NC) on human cytochrome P450-dependent monooxygenases in human hepatoma HepG2 cells. Treatment of HepG2 cells with 6-NC increased the activities of microsomal benzo[a]pyrene hydroxylase, 7-ethoxycoumarin and 7-ethoxyresorufin O-deethylases, cytosolic glutathione S-transferase and N-acetyltransferase, and S9 metabolic activation of 6-NC in the Ames mutagenicity test. Immunoblot and RNA blot analyses revealed that 6-NC induced CYP1A1 protein and mRNA levels in the hepatoma cells. Nuclear transcription assay demonstrated that 6-NC increased the transcription rate of CYP1A1 gene in HepG2 cells. Treatment of human lung carcinoma NCI-H322 cells with 6-NC increased benzo[a]pyrene hydroxylase activity and CYP1A1 protein and mRNA levels. These results demonstrate that 6-NC is an inducer of human CYP1A1 and the induction occurs at a transcriptional level in HepG2 cells. The ability of 6-NC to induce liver and lung CYP1A1 may be an important factor to consider in assessing 6-NC metabolism and toxicity in humans. Copyright (C) 2000 Elsevier Science Ireland Ltd.

Original languageEnglish
Pages (from-to)69-77
Number of pages9
JournalToxicology Letters
Issue number1-2
Publication statusPublished - Sept 30 2000


  • 6-Nitrochrysene
  • Cytochrome P450 1A1
  • HepG2 cells
  • Induction

ASJC Scopus subject areas

  • Toxicology


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