Carcinogenic polycyclic aromatic hydrocarbons induce CYP1A1 in human cells via a p53-dependent mechanism

Research output: Contribution to journalArticle

Abstract

The tumour suppressor gene TP53 is mutated in more than 50 % of human tumours, making it one of the most important cancer genes. We have investigated the role of TP53 in cytochrome P450 (CYP)-mediated metabolic activation of three polycyclic aromatic hydrocarbons (PAHs) in a panel of isogenic colorectal HCT116 cells with differing TP53 status. Cells that were TP53(+/+), TP53(+/-), TP53(-/-), TP53(R248W/+) or TP53(R248W/-) were treated with benzo[a]pyrene (BaP), dibenz[a,h]anthracene and dibenzo[a,l]pyrene, and the formation of DNA adducts was measured by (32)P-postlabelling analysis. Each PAH formed significantly higher DNA adduct levels in TP53(+/+) cells than in the other cell lines. There were also significantly lower levels of PAH metabolites in the culture media of these other cell lines. Bypass of the need for metabolic activation by treating cells with the corresponding reactive PAH-diol-epoxide metabolites resulted in similar adduct levels in all cell lines, which confirms that the influence of p53 is on the metabolism of the parent PAHs. Western blotting showed that CYP1A1 protein expression was induced to much greater extent in TP53(+/+) cells than in the other cell lines. CYP1A1 is inducible via the aryl hydrocarbon receptor (AHR), but we did not find that expression of AHR was dependent on p53; rather, we found that BaP-induced CYP1A1 expression was regulated through p53 binding to a p53 response element in the CYP1A1 promoter region, thereby enhancing its transcription. This study demonstrates a new pathway for CYP1A1 induction by environmental PAHs and reveals an emerging role for p53 in xenobiotic metabolism.

Details

Authors
  • Laura E Wohak
  • Annette M Krais
  • Jill E Kucab
  • Julia Stertmann
  • Steinar Øvrebø
  • Albrecht Seidel
  • David H. Phillips
  • Volker M Arlt
External organisations
  • King's College London
Research areas and keywords

Keywords

  • Basic Helix-Loop-Helix Transcription Factors, Benzo(a)pyrene, Carcinogens, Cell Survival, Cytochrome P-450 CYP1A1, Cytochrome P-450 CYP1B1, Cytochrome P-450 Enzyme Inducers, DNA Adducts, DNA Damage, HCT116 Cells, Humans, Inactivation, Metabolic, NAD(P)H Dehydrogenase (Quinone), Polycyclic Aromatic Hydrocarbons, Receptors, Aryl Hydrocarbon, Toxicity Tests, Tumor Suppressor Protein p53, Journal Article, Research Support, Non-U.S. Gov't
Original languageEnglish
Pages (from-to)291-304
Number of pages14
JournalArchiv fur Toxikologie
Volume90
Issue number2
Publication statusPublished - 2016 Feb
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes