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Updated: Jun 8, 2026
10:51
Reverse Yeast Two-hybrid System to Identify Mammalian Nuclear Receptor Residues that Interact with Ligands and/or Antagonists
Published on: November 15, 2013
Human CYP2A6 is regulated by nuclear factor-erythroid 2 related factor 2
Shin-Ichi Yokota1, Eriko Higashi, Tatsuki Fukami
1Drug Metabolism and Toxicology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
Biochemical Pharmacology
|October 5, 2010
Summary
The study reveals that the human enzyme CYP2A6, crucial for metabolizing nicotine and activating tobacco carcinogens, is regulated by Nrf2. This finding suggests CYP2A6 induction occurs during oxidative stress.
Area of Science:
- Biochemistry
- Molecular Biology
- Toxicology
Background:
- Human CYP2A6 metabolizes nicotine, coumarin, and activates tobacco-related nitrosamines.
- Previous studies indicated dietary cadmium or cruciferous vegetables increase CYP2A6 activity, but mechanisms were unclear.
- This research investigated the potential role of Nrf2 in regulating CYP2A6.
Purpose of the Study:
- To determine if Nrf2 is involved in the regulation of human CYP2A6.
- To elucidate the molecular mechanisms underlying CYP2A6 induction by Nrf2 activators.
Main Methods:
- Real-time RT-PCR to measure CYP2A6 mRNA levels.
- Bioinformatic analysis to identify potential Nrf2 binding sites (AREs) in the CYP2A6 gene promoter.
- Electrophoretic mobility shift assays (EMSA) to confirm Nrf2 binding to AREs.
- Luciferase reporter assays in HepG2 cells and in vivo in mice to assess transcriptional activity.
Main Results:
- Sulforaphane (SFN), an Nrf2 activator, significantly induced CYP2A6 mRNA in human hepatocytes.
- Nrf2 was found to bind to a specific ARE (ARE1) in the CYP2A6 5'-flanking region.
- Nrf2 overexpression enhanced reporter activity from a construct containing ARE1, but not the full promoter region in HepG2 cells.
- In vivo, SFN administration significantly increased reporter activity in mouse liver, indicating Nrf2-mediated regulation.
Conclusions:
- Human CYP2A6 is regulated by Nrf2, a key transcription factor in the cellular response to oxidative stress.
- This study provides mechanistic insight into how dietary compounds and oxidative stress can modulate CYP2A6 activity.
- The findings suggest that CYP2A6 induction is linked to cellular oxidative stress responses.
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