title: Modulation of Nrf2/Keap1 system by Wasabi 6-methylthiohexyl isothiocyanate in ARE-mediated NQO1 expression.
abstract: METHODS
  6-Methylthiohexyl isothiocyanate (6-MTITC), one of the major bioactive ingredients in Japanese Wasabi, has revealed cytoprotective and cancer chemopreventive effects. This study aims to clarify the molecular mechanisms how 6-MTITC modulates nuclear factor E2-related factor 2 (Nrf2)/Kelchlike ECH-associating protein 1 (Keap1) system in antioxidant-responsive element (ARE)-mediated nicotinamide adenine dinucleotide phosphate (NADP): quinone oxidoreductase 1 (NQO1) expression.
  
  
  RESULTS
  HepG2 cells were treated with 6-MTITC with varying time and dose. NQO1, Nrf2, and Keap1 proteins were detected by Western blotting. ARE transactivation was detected by electrophilic mobility shift assay and reporter gene assay. Nuclear localization of Nrf2 was determined by immunocytochemistry assay. Ubiquitination of Nrf2 and Keap1 was detected using immunoprecipitation after treatment with MG132. Small interfering RNA was used to knockdown Nrf2 or Keap1. The results revealed that 6-MTITC modulated Nrf2/ARE pathway by stimulating Keap1 modification, and inhibiting Nrf2 ubiquitination and protein turnover. These actions finally increased nuclear Nrf2 accumulation and ARE-binding activity. Moreover, silencing Nrf2 markedly reduced ARE-driven activity induced by 6-MTITC.
  
  
  CONCLUSIONS
  6-MTITC modulated ARE-driven NQO1 expression by stabilizing Nrf2 with enhanced Keap1 modification and decreased Nrf2 degradation.
authors: Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, Korimoto, Kagoshima, Japan.
authors: Yoshimi
authors: Y
authors: Korenori
authors: Shunsuke
authors: S
authors: Tanigawa
authors: Takuma
authors: T
authors: Kumamoto
authors: Si
authors: S
authors: Qin
authors: Yosuke
authors: Y
authors: Daikoku
authors: Koji
authors: K
authors: Miyamori
authors: Masashi
authors: M
authors: Nagai
authors: De-Xing
authors: DX
authors: Hou
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D019610:Cytoprotection; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D056945:Hep G2 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D017879:Isothiocyanates / Q000494:pharmacology*; D000072019:Kelch-Like ECH-Associated Protein 1; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics / Q000378:metabolism*; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements / Q000187:drug effects; D015398:Signal Transduction; D031228:Wasabia / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D047908:Intracellular Signaling Peptides and Proteins; D017879:Isothiocyanates; C431364:KEAP1 protein, human; D000072019:Kelch-Like ECH-Associated Protein 1; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; C410683:6-methylthiohexyl isothiocyanate; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human