Benzo[g,h,i]perylene synergistically transactivates benzo[a]pyrene-induced CYP1A1 gene expression by aryl hydrocarbon receptor pathway

Shur Hueih Cherng, Pinpin Lin, Jia Ling Yang, Shih Lan Hsu, Huei Lee

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Although benzo[g,h,i]perylene (BghiP) has been found to promote the carcinogenesis of benzo[a]pyrene (BaP) in animal models, not much is known about this cocarcinogenic mechanism. In this study, human hepatoma HepG2 cells cotreated with BaP and BghiP were used as a model to investigate the cocarcinogenic mechanism of BghiP in BaP-induced carcinogenesis. DNA adduct formation is thought to initiate carcinogenesis, so the effect of BghiP on BaP-DNA adduct formation was evaluated using a 32P-postlabeling assay. The BaP-DNA adduct levels increased following the addition of BghiP, in a dose-dependent manner. However, no adducts were formed with BghiP alone. Our previous report showed that cytochrome P450 1A1 (CYP1A1) is responsible for the metabolic activation of BaP and the formation of B[a]P adduct in HepG2 cells. Western blot and Northern blot analyses were used to evaluate whether BaP-induced CYP1A1 protein and mRNA levels increased following the addition of BghiP. Our data showed that BghiP enhanced BaP-induced CYP1A1 protein and its mRNA levels. To understand whether BghiP enhances BaP-induced CYP1A1 gene expression through the aryl hydrocarbon receptor (AhR) signaling pathway, a gel retardation assay was performed to elucidate the synergistic mechanism of BghiP in BaP-induced CYP1A1 gene expression. The results showed that BghiP causes an increase in the nuclear accumulation of AhR in cells and/or activation of AhR to a DNA-binding form. There was a concordant increase in the transcription activation of CYP1A1 gene and the induction of AhR signal pathway. Our findings demonstrated that BghiP enhances BaP-induced CYP1A1 transcription by AhR activation and suggested that the induction mechanism of CYP1A1 contributes to the cocarcinogenic potential of BghiP in BaP-induced carcinogenesis.

Original languageEnglish
Pages (from-to)63-68
Number of pages6
JournalToxicology and Applied Pharmacology
Volume170
Issue number1
DOIs
Publication statusPublished - Jan 1 2001
Externally publishedYes

Fingerprint

Perylene
Aryl Hydrocarbon Receptors
Benzo(a)pyrene
Gene expression
Cytochrome P-450 Enzyme System
Gene Expression
Carcinogenesis
Chemical activation
Hep G2 Cells
Transcription
Assays
Messenger RNA
DNA Adducts
Electrophoretic Mobility Shift Assay

Keywords

  • Ah receptor pathway
  • Benzo[a]pyrene
  • Benzo[g,h,i]perylene
  • CYP1A1

ASJC Scopus subject areas

  • Pharmacology
  • Toxicology

Cite this

Benzo[g,h,i]perylene synergistically transactivates benzo[a]pyrene-induced CYP1A1 gene expression by aryl hydrocarbon receptor pathway. / Cherng, Shur Hueih; Lin, Pinpin; Yang, Jia Ling; Hsu, Shih Lan; Lee, Huei.

In: Toxicology and Applied Pharmacology, Vol. 170, No. 1, 01.01.2001, p. 63-68.

Research output: Contribution to journalArticle

Cherng, Shur Hueih ; Lin, Pinpin ; Yang, Jia Ling ; Hsu, Shih Lan ; Lee, Huei. / Benzo[g,h,i]perylene synergistically transactivates benzo[a]pyrene-induced CYP1A1 gene expression by aryl hydrocarbon receptor pathway. In: Toxicology and Applied Pharmacology. 2001 ; Vol. 170, No. 1. pp. 63-68.
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