Toxicity of Trp-P-2 to cultured human and rat keratinocytes

Hyang Sook Chun, Paul A. Kuzmicky, Norman Y. Kado, Robert H. Rice

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Keratinocytes cultured from human and rat epidermis exhibited strongly divergent sensitivities to toxicity from the heterocyclic amine food mutagen Trp-P-2. To find a biochemical basis for this difference, the cultured cells were compared in their expression of phase 1 and 2 biotransformation activities, mutagenic activation and macromolecular adducts. The human and early passage rat cells expressed similar levels of ethoxyresorufin O-deethylase and N-acetyl transferase activities, their microsomes were similarly active in inducing bacterial mutagenesis when incubated with Trp-P-2, and the keratinocytes accumulated similar levels of DNA adducts over a 4-day treatment period. However, the human cells expressed an order of magnitude higher cytosolic glutathione S-transferase activity than the rat cells, likely providing enhanced protection. Late passage rat epidermal cells were insensitive to Trp-P-2 toxicity, attributable to their rapid loss of measured cytochrome P450 activity. Rat esophageal and fore-stomach epithelial cells resembled late passage rat epidermal cells in their lack of sensitivity to Trp-P-2 toxicity and lack of P450 activity. Human esophageal epithelial cells expressed substantial P450 activity but, in contrast to human epidermal cells, were sensitive to Trp-P-2 toxicity. Thus keratinocytes provide a valuable system in which to examine the basis for species- and tissue-specific differences in toxicity from this carcinogenic heterocyclic amine. Copyright (C) 2000 Elsevier Science Ireland Ltd.

Original languageEnglish (US)
Pages (from-to)237-253
Number of pages17
JournalChemico-Biological Interactions
Volume127
Issue number3
DOIs
StatePublished - Jul 14 2000

Keywords

  • Bacterial mutagenicity
  • Cytochrome P450
  • EROD
  • Heterocyclic amines
  • TCDD

ASJC Scopus subject areas

  • Toxicology

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