Ajoene, a Major Organosulfide Found in Crushed Garlic, Induces NAD(P)H:quinone Oxidoreductase Expression Through Nuclear Factor E2-related Factor-2 Activation in Human Breast Epithelial Cells
10.15430/JCP.2019.24.2.112
- Author:
Seung Ju CHO
1
;
Jae Ha RYU
;
Young Joon SURH
Author Information
1. Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Seoul, Korea. surh@snu.ac.kr
- Publication Type:Original Article
- Keywords:
Ajoene;
Garlic;
Nuclear factor E2-related factor 2;
NAD(P)H:quinone oxidoreductase 1;
Extracellular signal-regulated kinase;
Reactive oxygen species
- MeSH:
Acetylcysteine;
Adenine;
Antioxidant Response Elements;
Azo Compounds;
Blotting, Western;
Breast;
Consensus Sequence;
Epithelial Cells;
Flavoproteins;
Garlic;
Genes, Reporter;
Glutathione;
Humans;
Luciferases;
NF-E2-Related Factor 2;
Oxidation-Reduction;
Phosphotransferases;
Quinones;
Reactive Oxygen Species;
RNA, Small Interfering;
Up-Regulation
- From:Journal of Cancer Prevention
2019;24(2):112-122
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND: NAD(P)H:quinone oxidoreductase-1 (NQO1) is a widely-distributed flavin adenine dinucleotide-dependent flavoprotein that promotes obligatory 2-electron reductions of quinones, quinoneimines, nitroaromatics, and azo dyes. This reduces quinone levels and thereby minimizes generation of excess reactive oxygen species (ROS) formed by redox cycling, and concurrent depletion of intracellular thiol pools. Ajoene is derived from crushed garlic. It is formed by a reaction involving two allicin molecules, and is composed of allyl sulfide and vinyl disulfide. Ajoene is present in two isomers, E- and Z-form. METHODS: Expression of antioxidant enzymes and nuclear factor E2-related factor-2 (Nrf2) was measured by Western blot analysis. NQO1 promoter activity was assessed by the luciferase reporter gene assay. ROS accumulation was monitored by using the fluorescence-generating probe 2′,7′-dichlorofluorescein diacetate. The intracellular glutathione levels were measured by using a commercially available kit. RESULTS: Z-ajoene significantly up-regulated the expression of representative antioxidant enzyme NQO1 in non-tumorigenic breast epithelial MCF-10A cells at non-toxic concentrations. Z-ajoene enhanced up-regulation and nuclear translocation of Nrf2, which plays a pivotal role in the induction of many genes encoding antioxidant enzymes and other cytoprotective proteins. Z-ajoene treatment also increased the activity of nqo1-promoter harboring antioxidant response element consensus sequences in MCF-10A cells. Silencing of Nrf2 by small interfering RNA abrogated ajoene-induced expression of NQO1. Z-ajoene activated extracellular signal-regulated kinase (ERK). Inhibition of ERK activation by U0126 abrogated ability of Z-ajoene to activate Nrf2 and to induce NQO1 expression. Intracellular ROS accumulation was observed after treatment with Z-ajoene, whereas the E-isoform was not effective. The inhibition of ROS by treatment with N-acetylcysteine, a radical scavenger, abrogated Z-ajoene-induced expression of NQO1 as well as activation of ERK and Nrf2, suggesting that Z-ajoene augments the Nrf2-dependent antioxidant defense via ROS generation and ERK activation. CONCLUSIONS: Z-ajoene induces NQO1 expression in MCF-10A cells through ROS-mediated activation of Nrf2.
