Down-regulation of Cytochrome P450 1A1 Gene Promoter by Oxidative Stress

doi:10.1074/jbc.273.41.26969

Down-regulation of Cytochrome P450 1A1 Gene Promoter by Oxidative Stress

CRITICAL CONTRIBUTION OF NUCLEAR FACTOR 1*

Yannick Morel‡ and
Robert Barouki§

From INSERM U490, Centre Universitaire des Saints-Pères, 45 rue des Saints-Pères, 75006 Paris, France

Abstract

Oxidative stress interferes with several cellular functions, in particular transcriptional regulation. We show here that the human cytochrome P450 1A1 (CYP1A1) is down-regulated at the transcriptional level by oxidative stress. Basal as well as 2,3,7,8-tetrachloro-p-dioxin-induced promoter activities are strongly impaired by H₂O₂ treatment or glutathione depletion with l-buthionine-(S,R)-sulfoximine. Tumor necrosis factor α inhibits CYP1A1 expression, and this inhibition is prevented by the antioxidant pyrrolidine dithiocarbamate. We show that these regulations depend on the integrity of the nuclear factor 1 (NFI) site located in the proximal promoter. We therefore examined the redox regulation of this transcription factor. Treatment of human HepG2 or rat H4 hepatoma cells with H₂O₂ orl-buthionine-(S,R)-sulfoximine inactivates the binding of the NFI transcription factor to its DNA consensus sequence. Furthermore, H₂O₂ treatment leads to a dose-dependent decrease of reporter gene expressions driven by promoters containing NFI binding sites. Glutathione depletion and catalase inhibition also repress a NFI-driven promoter. Under the same conditions, the CP-1 transcription factor activity is not affected by oxidative stress. Thus, NFI seems particularly sensitive to oxidative stress. This accounts, at least partially, for the regulation ofcyp1A1 gene expression.

Footnotes

↵* This work was supported by INSERM, University Paris-Val de Marne, and Association pour la Recherche contre le Cancer Grant 6604.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵‡ A fellow of the Délègation Généraleà l’Arnement.
↵§ To whom correspondence should be addressed: Tel.: 33 1 42 86 20 75; Fax: 33 1 42 86 20 72; E-mail:robert.barouki{at}biomedicale.univparis5.fr.
↵2 Y. Morel and R. Barouki, unpublished observations.
Abbreviations:

CYP

cytochrome P450 monooxygenase

TCDD

2,3,7,8-tetrachloro-p-dioxine

BSO

l-buthionine-(S,R)-sulfoximine

TNFα

tumor necrosis factor-α

Ah

aryl hydrocarbon

NFI

nuclear factor 1

EMSA

electrophoretic mobility shift assay

CAT

chloramphenicol acetyltransferase

CTF

CAAT transcription factor

PDTC

pyrrolidine dithiocarbamate.
- Received March 5, 1998.
- Revision received June 11, 1998.
The American Society for Biochemistry and Molecular Biology, Inc.