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Zhang T, He C, Ota S, Kitakaze T, Yamaji R, Shimazu S, Yamashita Y, Ashida H. A Natural Chalcone Cardamonin Inhibited Transformation of Aryl Hydrocarbon Receptor Through Binding to the Receptor Competitively. Mol Nutr Food Res 2024; 68:e2400185. [PMID: 39165052 DOI: 10.1002/mnfr.202400185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 07/21/2024] [Indexed: 08/22/2024]
Abstract
SCOPE Chalcones are widely present in most plants and have various health beneficial functions. This study investigates the suppressive effect of 13 natural and synthetic chalcones on transformation of aryl hydrocarbon receptor (AhR) induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3-methylcholanthrene (3-MC) in a cell-free system, Hepa-1c1c7 cells, and liver of ICR mice. METHODS AND RESULTS In the cell-free system, cardamonin dose-dependently inhibits AhR transformation. Chalcones with substitution on 2' and/or 6' position is important for the suppressive effect, while the substitution on 4' position is negatively for the effect. Moreover, cardamonin and 2'-hydroxychalcone competitively inhibit the binding of [3H]-3-MC to the AhR. In Hepa-1c1c7 cells, cardamonin inhibits AhR transformation and expression of cytochrome P4501A1 (CYP1A1) in a dose-dependent manner through suppressing TCDD-induced phosphorylation of both AhR and AhR nuclear translocator, heterodimerization of them, and nuclear translocation of AhR. In the liver of mice, oral administered cardamonin also inhibits 3-MC-induced AhR translocation and expression of CYP1A1. CONCLUSION Among used chalcones, a natural chalcone cardamonin competitively binds to AhR and suppresses its transformation. Thus, cardamonin is an effective food factor for suppression of the dioxin-caused biochemical alterations and toxicities.
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Affiliation(s)
- Tianshun Zhang
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
- The Hormel Institute, University of Minnesota, Austin, Minnesota. 801 16th Ave NE, Austin, MN, 559122, USA
| | - Chao He
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Shieru Ota
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Tomoya Kitakaze
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Osaka, Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8331, Japan
| | - Ryoichi Yamaji
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Osaka, Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8331, Japan
| | - Sayuri Shimazu
- Research Facility Center for Science and Technology, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Yoko Yamashita
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Hitoshi Ashida
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
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Mukai R, Okuyama H, Uchimura M, Sakao K, Matsuhiro M, Ikeda-Imafuku M, Ishima Y, Nishikawa M, Ikushiro S, Tai A. The binding selectivity of quercetin and its structure-related polyphenols to human serum albumin using a fluorescent dye cocktail for multiplex drug-site mapping. Bioorg Chem 2024; 145:107184. [PMID: 38364549 DOI: 10.1016/j.bioorg.2024.107184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/25/2024] [Accepted: 02/04/2024] [Indexed: 02/18/2024]
Abstract
Human serum albumin (HSA) is a serum protein that carries flavonoids in blood circulation. In this report, the binding selectivity and strength of interactions to HSA-binding sites (sites I or II) by flavonoids were evaluated using competition experiments and the specific fluorescent dyes, dansylamide and BD140. Most tested flavonoids bound site I preferentially, with the binding strength dependent on the mother structure in the order flavonol > flavone > flavanone > flavan 3-ols. Glycosylation or glucuronidation reduced the binding of quercetin to site I of HSA, whereas sulfation increased binding. Quercetin 7-sulfate showed the strongest binding and molecular docking simulations supported this observation. Prenylation at any position or glucuronidation and sulfation at the C-4' or C-7 position of quercetin facilitated stronger binding to site II. The binding affinity of flavonoids toward site I correlated with the partition coefficient value (logP), whereas no corresponding correlation was observed for site II.
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Affiliation(s)
- Rie Mukai
- Department of Food Science, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, 2-1, Minamijosan-jima, Tokushima 770-8513, Japan.
| | - Hitomi Okuyama
- Department of Food Science, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, 2-1, Minamijosan-jima, Tokushima 770-8513, Japan
| | - Miku Uchimura
- Department of Food Science and Technology, Graduate School of Agriculture, Kagoshima University, 1-21-24, Korimoto, Kagoshima 890-0065, Japan.
| | - Kozue Sakao
- Department of Food Science and Technology, Graduate School of Agriculture, Kagoshima University, 1-21-24, Korimoto, Kagoshima 890-0065, Japan.
| | - Miyu Matsuhiro
- Department of Food Science, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, 2-1, Minamijosan-jima, Tokushima 770-8513, Japan.
| | - Mayumi Ikeda-Imafuku
- Department of Physical Pharmaceutics, School of Pharmaceutical Sciences, Wakayama Medical University, 25-1 Shichiban-cho, Wakayama 640-8156, Japan.
| | - Yu Ishima
- Laboratory of Biopharmaceutics, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
| | - Miyu Nishikawa
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan.
| | - Shinichi Ikushiro
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan.
| | - Akihiro Tai
- Department of Food Science, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, 2-1, Minamijosan-jima, Tokushima 770-8513, Japan.
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3
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Lyubitelev A, Studitsky V. Inhibition of Cancer Development by Natural Plant Polyphenols: Molecular Mechanisms. Int J Mol Sci 2023; 24:10663. [PMID: 37445850 PMCID: PMC10341686 DOI: 10.3390/ijms241310663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 07/15/2023] Open
Abstract
Malignant tumors remain one of the main sources of morbidity and mortality around the world. A chemotherapeutic approach to cancer treatment poses a multitude of challenges, primarily due to the low selectivity and genotoxicity of the majority of chemotherapeutic drugs currently used in the clinical practice, often leading to treatment-induced tumors formation. Highly selective antitumor drugs can largely resolve this issue, but their high selectivity leads to significant drawbacks due to the intrinsic tumor heterogeneity. In contrast, plant polyphenols can simultaneously affect many processes that are involved in the acquiring and maintaining of hallmark properties of malignant cells, and their toxic dose is typically much higher than the therapeutic one. In the present work we describe the mechanisms of the action of polyphenols on cancer cells, including their effects on genetic and epigenetic instability, tumor-promoting inflammation, and altered microbiota.
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Affiliation(s)
| | - Vasily Studitsky
- Biology Faculty, Lomonosov Moscow State University, 119234 Moscow, Russia;
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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4
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Pinto CJG, Ávila-Gálvez MÁ, Lian Y, Moura-Alves P, Nunes Dos Santos C. Targeting the aryl hydrocarbon receptor by gut phenolic metabolites: A strategy towards gut inflammation. Redox Biol 2023; 61:102622. [PMID: 36812782 PMCID: PMC9958510 DOI: 10.1016/j.redox.2023.102622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
The Aryl Hydrocarbon Receptor (AHR) is a ligand-dependent transcription factor able to control complex transcriptional processes in several cell types, which has been correlated with various diseases, including inflammatory bowel diseases (IBD). Numerous studies have described different compounds as ligands of this receptor, like xenobiotics, natural compounds, and several host-derived metabolites. Dietary (poly)phenols have been studied regarding their pleiotropic activities (e.g., neuroprotective and anti-inflammatory), but their AHR modulatory capabilities have also been considered. However, dietary (poly)phenols are submitted to extensive metabolism in the gut (e.g., gut microbiota). Thus, the resulting gut phenolic metabolites could be key players modulating AHR since they are the ones that reach the cells and may exert effects on the AHR throughout the gut and other organs. This review aims at a comprehensive search for the most abundant gut phenolic metabolites detected and quantified in humans to understand how many have been described as AHR modulators and what could be their impact on inflammatory gut processes. Even though several phenolic compounds have been studied regarding their anti-inflammatory capacities, only 1 gut phenolic metabolite, described as AHR modulator, has been evaluated on intestinal inflammatory models. Searching for AHR ligands could be a novel strategy against IBD.
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Affiliation(s)
- Catarina J G Pinto
- iNOVA4Health, NOVA Medical School
- Faculdade de Ciências Médicas, NMS
- FCM, Universidade Nova de Lisboa, Lisboa, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal; I3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal
| | - María Ángeles Ávila-Gálvez
- iNOVA4Health, NOVA Medical School
- Faculdade de Ciências Médicas, NMS
- FCM, Universidade Nova de Lisboa, Lisboa, Portugal; iBET, Instituto de Biologia Experimental e Tecnológica, Apartado 12, Oeiras, Portugal
| | - Yilong Lian
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, OX3 7DQ, Oxford, United Kingdom
| | - Pedro Moura-Alves
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal; I3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal; Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, OX3 7DQ, Oxford, United Kingdom.
| | - Cláudia Nunes Dos Santos
- iNOVA4Health, NOVA Medical School
- Faculdade de Ciências Médicas, NMS
- FCM, Universidade Nova de Lisboa, Lisboa, Portugal; iBET, Instituto de Biologia Experimental e Tecnológica, Apartado 12, Oeiras, Portugal.
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Ye Q, Xi X, Fan D, Cao X, Wang Q, Wang X, Zhang M, Wang B, Tao Q, Xiao C. Polycyclic aromatic hydrocarbons in bone homeostasis. Biomed Pharmacother 2021; 146:112547. [PMID: 34929579 DOI: 10.1016/j.biopha.2021.112547] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/03/2021] [Accepted: 12/13/2021] [Indexed: 01/16/2023] Open
Abstract
Prolonged exposure to polycyclic aromatic hydrocarbons (PAHs) may result in autoimmune diseases, such as rheumatoid arthritis (RA) and osteoporosis (OP), which are based on an imbalance in bone homeostasis. These diseases are characterized by bone erosion and even a disruption in homeostasis, including in osteoblasts and osteoclasts. Current evidence indicates that multiple factors affect the progression of bone homeostasis, such as genetic susceptibility and epigenetic modifications. However, environmental factors, especially PAHs from various sources, have been shown to play an increasingly prominent role in the progression of bone homeostasis. Hence, it is essential to investigate the effects and pathogenesis of PAHs in bone homeostasis. In this review, recent progress is summarized concerning the effects and mechanisms of PAHs and their ligands and receptors in bone homeostasis. Moreover, strategies based on the effects and mechanisms of PAHs in the regulation of the bone balance and alleviation of bone destruction are also reviewed. We further discuss the future challenges and perspectives regarding the roles of PAHs in autoimmune diseases based on bone homeostasis.
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Affiliation(s)
- Qinbin Ye
- Beijing University of Chinese Medicine, Beijing 100029, China; Institute of Clinical Medicine, China-Japan Friendship Hospital, Beijing 100029, China
| | - Xiaoyu Xi
- Beijing University of Chinese Medicine, Beijing 100029, China; Institute of Clinical Medicine, China-Japan Friendship Hospital, Beijing 100029, China
| | - Danping Fan
- Institute of Clinical Medicine, China-Japan Friendship Hospital, Beijing 100029, China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences/Peking Union Medical College, Beijing 100193, China
| | - Xiaoxue Cao
- Institute of Clinical Medicine, China-Japan Friendship Hospital, Beijing 100029, China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences/Peking Union Medical College, Beijing 100193, China
| | - Qiong Wang
- Beijing University of Chinese Medicine, Beijing 100029, China; Institute of Clinical Medicine, China-Japan Friendship Hospital, Beijing 100029, China
| | - Xing Wang
- Beijing University of Chinese Medicine, Beijing 100029, China; Institute of Clinical Medicine, China-Japan Friendship Hospital, Beijing 100029, China
| | - Mengxiao Zhang
- Institute of Clinical Medicine, China-Japan Friendship Hospital, Beijing 100029, China
| | - Bailiang Wang
- Department of Orthopaedic Surgery, Center for Osteonecrosis and Joint Preserving & Reconstruction, China-Japan Friendship Hospital, Beijing 100029, China.
| | - Qingwen Tao
- Department of TCM Rheumatology, China-Japan Friendship Hospital, Beijing 100029, China.
| | - Cheng Xiao
- Institute of Clinical Medicine, China-Japan Friendship Hospital, Beijing 100029, China; Department of Emergency, China-Japan Friendship Hospital, Beijing 100029, China.
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6
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Plant Occurring Flavonoids as Modulators of the Aryl Hydrocarbon Receptor. Molecules 2021; 26:molecules26082315. [PMID: 33923487 PMCID: PMC8073824 DOI: 10.3390/molecules26082315] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 12/26/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a transcription factor deeply implicated in health and diseases. Historically identified as a sensor of xenobiotics and mainly toxic substances, AhR has recently become an emerging pharmacological target in cancer, immunology, inflammatory conditions, and aging. Multiple AhR ligands are recognized, with plant occurring flavonoids being the largest group of natural ligands of AhR in the human diet. The biological implications of the modulatory effects of flavonoids on AhR could be highlighted from a toxicological and environmental concern and for the possible pharmacological applicability. Overall, the possible AhR-mediated harmful and/or beneficial effects of flavonoids need to be further investigated, since in many cases they are contradictory. Similar to other AhR modulators, flavonoids commonly exhibit tissue, organ, and species-specific activities on AhR. Such cellular-context dependency could be probably beneficial in their pharmacotherapeutic use. Flavones, flavonols, flavanones, and isoflavones are the main subclasses of flavonoids reported as AhR modulators. Some of the structural features of these groups of flavonoids that could be influencing their AhR effects are herein summarized. However, limited generalizations, as well as few outright structure-activity relationships can be suggested on the AhR agonism and/or antagonism caused by flavonoids.
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7
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Riemschneider S, Hoffmann M, Slanina U, Weber K, Hauschildt S, Lehmann J. Indol-3-Carbinol and Quercetin Ameliorate Chronic DSS-Induced Colitis in C57BL/6 Mice by AhR-Mediated Anti-Inflammatory Mechanisms. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18052262. [PMID: 33668818 PMCID: PMC7956562 DOI: 10.3390/ijerph18052262] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/19/2021] [Accepted: 02/20/2021] [Indexed: 12/14/2022]
Abstract
Inflammatory bowel diseases (IBD), such as Crohn’s disease and ulcerative colitis, are multifactorial inflammatory disorders of the gastrointestinal tract, characterised by abdominal cramps, bloody diarrhoea, and anaemia. Standard therapies, including corticosteroids or biologicals, often induce severe side effects, or patients may develop resistance to those therapies. Thus, new therapeutic options for IBD are urgently needed. This study investigates the therapeutic efficacy and safety of two plant-derived ligands of the aryl hydrocarbon receptor (AhR), quercetin (Q), and indol-3-carbinol (I3C), using a translationally relevant mouse model of IBD. Q and I3C are administered by gavage to C57BL/6 wild-type or C57BL/6 Ahr-/- mice suffering from chronic colitis, induced by dextran sulphate sodium (DSS). The course of the disease, intestinal histopathological changes, and in-situ immunological phenotype are scored over 25 days. Our results show that both Q and I3C improved significantly clinical symptoms in moderate DSS colitis, which coincides with a significantly reduced histopathological score. Even in severe DSS colitis I3C, neither Q nor the therapy control 6-thioguanine (6-TG) can prevent a fatal outcome. Moreover, treatment with Q or I3C restored in part DSS-induced loss of epithelial integrity by induction of tight-junction proteins and reduced significantly gut inflammation, as demonstrated by colonoscopy, as well as by immunohistochemistry revealing lower numbers of neutrophils and macrophages. Moreover, the number of Th17 cells is significantly reduced, while the number of Treg cells is significantly increased by treatment with Q or I3C, as well as 6-TG. Q- or I3C-induced amelioration of colitis is not observed in Ahr-/- mice suggesting the requirement of AhR ligation and signalling. Based on the results of this study, plant-derived non-toxic AhR agonists can be considered promising therapeutics in IBD therapy in humans. However, they may differ in terms of efficacy; therefore, it is indispensable to study the dose-response relationship of each individual AhR agonist also with regard to potential adverse effects, since they may also exert AhR-independent effects.
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Affiliation(s)
- Sina Riemschneider
- Department of Therapy Validation, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany; (S.R.); (M.H.); (U.S.)
| | - Maximilian Hoffmann
- Department of Therapy Validation, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany; (S.R.); (M.H.); (U.S.)
| | - Ulla Slanina
- Department of Therapy Validation, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany; (S.R.); (M.H.); (U.S.)
| | | | - Sunna Hauschildt
- Faculty of Life Sciences, University of Leipzig, 04103 Leipzig, Germany;
| | - Jörg Lehmann
- Department of Therapy Validation, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany; (S.R.); (M.H.); (U.S.)
- Fraunhofer Cluster of Excellence Immune-Mediated Diseases CIMD, 04103 Leipzig, Germany
- Correspondence:
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8
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Ye M, Xu M, Fan S, Zhang M, Zhou B, Yang S, Wei W, Ji C, Ji J, Ji F. Protective effects of three propolis-abundant flavonoids against ethanol-induced injuries in HepG2 cells involving the inhibition of ERK1/2-AHR-CYP1A1 signaling pathways. J Funct Foods 2020. [DOI: 10.1016/j.jff.2020.104166] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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9
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Park H, Jin UH, Orr AA, Echegaray SP, Davidson LA, Allred CD, Chapkin RS, Jayaraman A, Lee K, Tamamis P, Safe S. Isoflavones as Ah Receptor Agonists in Colon-Derived Cell Lines: Structure-Activity Relationships. Chem Res Toxicol 2019; 32:2353-2364. [PMID: 31621310 DOI: 10.1021/acs.chemrestox.9b00352] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many of the protective responses observed for flavonoids in the gastrointestinal track resemble aryl hydrocarbon receptor (AhR)-mediated effects. Therefore, we examined the structure-activity relationships of isoflavones and isomeric flavone and flavanones as AhR ligands on the basis of their induction of CYP1A1, CYP1B1, and UGT1A1 gene expression in colon cancer Caco2 cells and young adult mouse colonocyte (YAMC) cells. Caco2 cells were significantly more Ah-responsive than YAMC cells, and this was due, in part, to flavonoid-induced cytotoxicity in the latter cell lines. The structure-activity relationships for the flavonoids were complex and both response and cell context specific; however, there was significant variability in the AhR activities of the isomeric substituted isoflavones and flavones. For example, 4',5,7-trihydroxyisoflavone (genistein) was AhR-inactive whereas 4',5,7-trihydroxyflavone (apigenin) induced CYP1A1, CYP1B1, and UGT1A1 in Caco2 cells. In contrast, both 5,7-dihydroxy-4-methoxy substituted isoflavone (biochanin A) and flavone (acacetin) induced all three AhR-responsive genes; 4',5,7-trimethoxyisoflavone was a potent AhR agonist, and the isomeric flavone was AhR-inactive. These results coupled with simulation studies modeling flavonoid interaction within the AhR binding pocket demonstrate that the orientation of the substituted phenyl ring at C-2 (flavones) or C-3 (isoflavones) on the common 4-H-chromen-4-one ring strongly influences the activities of isoflavones and flavones as AhR agonists.
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Affiliation(s)
- Hyejin Park
- Department of Veterinary Physiology and Pharmacology , Texas A&M University , College Station , Texas 77843 , United States
| | - Un-Ho Jin
- Department of Veterinary Physiology and Pharmacology , Texas A&M University , College Station , Texas 77843 , United States
| | - Asuka A Orr
- Artie McFerrin Department of Chemical Engineering , Texas A&M University , College Station , Texas 77840 , United States
| | - Stephanie P Echegaray
- Artie McFerrin Department of Chemical Engineering , Texas A&M University , College Station , Texas 77840 , United States
| | - Laurie A Davidson
- Department of Nutrition and Food Science , Texas A&M University , College Station , Texas 77843 , United States
| | - Clinton D Allred
- Department of Nutrition and Food Science , Texas A&M University , College Station , Texas 77843 , United States
| | - Robert S Chapkin
- Department of Nutrition and Food Science , Texas A&M University , College Station , Texas 77843 , United States
| | - Arul Jayaraman
- Artie McFerrin Department of Chemical Engineering , Texas A&M University , College Station , Texas 77840 , United States
| | - Kyongbum Lee
- Department of Chemical and Biological Engineering , Tufts University , Medford , Massachusetts 02155 , United States
| | - Phanourios Tamamis
- Artie McFerrin Department of Chemical Engineering , Texas A&M University , College Station , Texas 77840 , United States
| | - Stephen Safe
- Department of Veterinary Physiology and Pharmacology , Texas A&M University , College Station , Texas 77843 , United States
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10
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Koper JEB, Loonen LMP, Wells JM, Troise AD, Capuano E, Fogliano V. Polyphenols and Tryptophan Metabolites Activate the Aryl Hydrocarbon Receptor in an in vitro Model of Colonic Fermentation. Mol Nutr Food Res 2018; 63:e1800722. [PMID: 30443985 PMCID: PMC6588005 DOI: 10.1002/mnfr.201800722] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/07/2018] [Indexed: 12/23/2022]
Abstract
Scope Many dietary phytochemicals have been reported to promote gut health. Specific dietary phytochemicals, such as luteolin, as well as specific microbial metabolites of tryptophan are ligands of the aryl hydrocarbon receptor (AhR), which plays a role in immunity and homeostasis of the gut barrier. Here, the fate of luteolin during colonic fermentation and the contribution of tryptophan metabolites to AhR activity in different parts of the colon are investigated. Methods and results Several polyphenols are screened for AhR activation and oregano, containing the ligand luteolin, is added to batch cultures of human microbiota from the distal colon. Luteolin is rapidly metabolized, with no measurable increase in AhR activity. In the second experiment, using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME), not all luteolin is metabolized in the ascending colon, but disappear rapidly in the transverse colon. The greatest AhR activity is due to microbiota‐derived metabolites of tryptophan, particularly in the descending colon. Conclusions Luteolin in food is rapidly metabolized in the transverse colon. Tryptophan metabolism by the microbiota in the colon contributes substantially to the pool of lumen metabolites that can activate the AhR.
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Affiliation(s)
- Jonna E B Koper
- Department of Agrotechnology & Food Sciences, Wageningen University, Wageningen, 6708 WG, The Netherlands.,Department of Animal Sciences, Wageningen University, Wageningen, 6708 WG, The Netherlands
| | - Linda M P Loonen
- Department of Animal Sciences, Wageningen University, Wageningen, 6708 WG, The Netherlands
| | - Jerry M Wells
- Department of Animal Sciences, Wageningen University, Wageningen, 6708 WG, The Netherlands
| | - Antonio Dario Troise
- Department of Agricultural Sciences, University of Naples "Federico II", Portici, 80055, Italy
| | - Edoardo Capuano
- Department of Agrotechnology & Food Sciences, Wageningen University, Wageningen, 6708 WG, The Netherlands
| | - Vincenzo Fogliano
- Department of Agrotechnology & Food Sciences, Wageningen University, Wageningen, 6708 WG, The Netherlands
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11
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Choi EM, Suh KS, Jung WW, Park SY, Chin SO, Rhee SY, Kim Pak Y, Chon S. Glabridin attenuates antiadipogenic activity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in murine 3T3-L1 adipocytes. J Appl Toxicol 2018; 38:1426-1436. [DOI: 10.1002/jat.3664] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/03/2018] [Accepted: 06/06/2018] [Indexed: 01/14/2023]
Affiliation(s)
- Eun Mi Choi
- Department of Endocrinology & Metabolism, School of Medicine; Kyung Hee University; Seoul 02447 Republic of Korea
| | - Kwang Sik Suh
- Department of Endocrinology & Metabolism, School of Medicine; Kyung Hee University; Seoul 02447 Republic of Korea
| | - Woon-Won Jung
- Department of Biomedical Laboratory Science, College of Health Sciences; Cheongju University; Cheongju Chungbuk 28503 Republic of Korea
| | - So Young Park
- Department of Medicine, Graduate School; Kyung Hee University; Seoul 02447 Republic of Korea
- Department of Endocrinology & Metabolism; Kyung Hee University Hospital; Seoul 02447 Republic of Korea
| | - Sang Ouk Chin
- Department of Endocrinology & Metabolism, School of Medicine; Kyung Hee University; Seoul 02447 Republic of Korea
- Department of Endocrinology & Metabolism; Kyung Hee University Hospital; Seoul 02447 Republic of Korea
| | - Sang Youl Rhee
- Department of Endocrinology & Metabolism, School of Medicine; Kyung Hee University; Seoul 02447 Republic of Korea
- Department of Endocrinology & Metabolism; Kyung Hee University Hospital; Seoul 02447 Republic of Korea
| | - Youngmi Kim Pak
- Department of Physiology; Kyung Hee University; College of Medicine Seoul 02447 Republic of Korea
| | - Suk Chon
- Department of Endocrinology & Metabolism, School of Medicine; Kyung Hee University; Seoul 02447 Republic of Korea
- Department of Endocrinology & Metabolism; Kyung Hee University Hospital; Seoul 02447 Republic of Korea
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Dvorak Z. Involvement of aryl hydrocarbon receptor (AhR) in polyphenol inhibition of benzo[a]pyrene-induced oxidative stress and neoplastic transformation. Food Chem Toxicol 2017; 107:523-525. [PMID: 28676325 DOI: 10.1016/j.fct.2017.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 06/29/2017] [Accepted: 07/01/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Zdenek Dvorak
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University Olomouc, Slechtitelu 27, 783 71 Olomouc, Czech Republic.
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Xue Z, Li D, Yu W, Zhang Q, Hou X, He Y, Kou X. Mechanisms and therapeutic prospects of polyphenols as modulators of the aryl hydrocarbon receptor. Food Funct 2017; 8:1414-1437. [DOI: 10.1039/c6fo01810f] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Polyphenolic AhR modulators displayed concentration-, XRE-, gene-, species- and cell-specific agonistic/antagonistic activity.
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Affiliation(s)
- Zhaohui Xue
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Dan Li
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Wancong Yu
- Medical Plant Laboratory
- Tianjin Research Center of Agricultural Biotechnology
- Tianjin 3000381
- China
| | - Qian Zhang
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Xiaonan Hou
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Yulong He
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Xiaohong Kou
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
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Rhon-Calderón EA, Galarza RA, Lomniczi A, Faletti AG. The systemic and gonadal toxicity of 3-methylcholanthrene is prevented by daily administration of α-naphthoflavone. Toxicology 2016; 353-354:58-69. [PMID: 27163632 DOI: 10.1016/j.tox.2016.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 04/25/2016] [Accepted: 05/05/2016] [Indexed: 11/24/2022]
Abstract
In the present study, we investigated the effect of 3-methylcholanthrene (3MC) on sexual maturity and the ability of α-naphthoflavone (αNF) to prevent this action. To this end, immature rats were daily injected intraperitoneally with 3MC (0.1 or 1mg/kg) and/or αNF (80mg/kg). Body weight, vaginal opening and estrous cycle were recorded and ovaries were obtained on the day of estrus. Ovarian weight, ovulation rate (measured by the number of oocytes within oviducts), and follicular development (determined by histology) were studied. No differences were found in body weight, ovarian weight, day of vaginal opening, or the establishment of the estrous cycle among the different groups of rats. However, animals treated with 3MC, at both doses, exhibited a lower number of primordial, primary, preantral and antral follicles than controls. Also, 3MC inhibited the ovulation rate and induced an overexpression of both the Cyp1a1 and Cyp1b1 genes, measured by chromatin immunoprecipitation assay. The daily treatment with αNF alone increased the number of follicles in most of the stages analyzed when compared with controls. Moreover, the αNF treatment prevented completely not only the 3MC-induced decrease in all types of follicles but also the 3MC-induced overexpression of Cyp enzymes and the genetic damage in bone marrow cells and oocytes. These results suggest that (i) daily exposure to 3MC during the pubertal period destroys the follicle reserve and alters the ovulation rate; (ii) the 3MC action seems to be mediated by an aryl hydrocarbon receptor-dependent mechanism; (iii) daily administration of αNF has a clear stimulatory action on the ovarian function; and (iv) αNF may prevent both the systemic and gonadal 3MC-induced toxicity.
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Affiliation(s)
- Eric Alejandro Rhon-Calderón
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Rocío Alejandra Galarza
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Alejandro Lomniczi
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006, USA
| | - Alicia Graciela Faletti
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
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15
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Ashida H, Harada K, Mishima S, Mitani T, Yamashita Y, Matsumura F. Luteolin suppresses TCDD-induced wasting syndrome in a cultured adipocyte model. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2015; 120:14-20. [PMID: 25987215 DOI: 10.1016/j.pestbp.2014.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 11/12/2014] [Accepted: 11/12/2014] [Indexed: 06/04/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) causes various toxic effects, including wasting syndrome, through activation of an aryl hydrocarbon receptor (AhR). Our previous report demonstrated that certain flavonoids inhibit the activation of AhR and suppress its DNA binding activity. In this study, we searched for an active compound among 13 flavonoids that suppressed TCDD-induced loss of lipid accumulation using 3T3-L1 adipocytes as a cell culture model for wasting syndrome. Two flavonoids, luteolin and epigallocatechin gallate, suppressed TCDD-induced loss of lipid accumulation in this model. We further investigated luteolin to clarify the underlying molecular mechanism and confirmed that luteolin inhibited nuclear translocation of AhR caused by TCDD. Luteolin also inhibited the TCDD-driven decrease in protein expression of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα). Although TCDD alone did not change protein expression of C/EBPβ and C/EBPδ, luteolin and TCDD up-regulated C/EBPδ expression in a dose-dependent manner. On the other hand, TCDD significantly decreased DNA binding of C/EBPβ and C/EBPδ, and luteolin completely canceled TCDD-decreased DNA binding of them. We conclude that luteolin suppresses the TCDD-induced loss of lipid accumulation in 3T3-L1 adipocytes by preventing a decrease in protein expression of PPARγ and C/EBPα, the master regulators of adipocyte differentiation and in DNA binding of C/EBPβ and C/EBPδ. Moreover, luteolin was rapidly incorporated and accumulated in 3T3-L1 adipocytes. Thus, luteolin is an attractive compound for the prevention of TCDD-induced wasting syndrome.
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Affiliation(s)
- Hitoshi Ashida
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan.
| | - Kiyonari Harada
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | - Sakiho Mishima
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | - Takakazu Mitani
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | - Yoko Yamashita
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | - Fumio Matsumura
- Department of Environmental Toxicology, University of California Davis, One Shields Avenue, CA 95616, USA
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Fukuda I, Nishiumi S, Mukai R, Yoshida KI, Ashida H. Catechins in tea suppress the activity of cytochrome P450 1A1 through the aryl hydrocarbon receptor activation pathway in rat livers. Int J Food Sci Nutr 2015; 66:300-7. [PMID: 25582180 DOI: 10.3109/09637486.2014.992007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) and halogenated aromatic hydrocarbons (HAHs) develop various adverse effects through activation of an aryl hydrocarbon receptor (AhR). The suppressive effects of brewed green tea and black tea on 3-methylcholanthrene (MC)-induced AhR activation and its downstream events were examined in the liver of rats. Ad-libitum drinking of green tea and black tea suppressed MC-induced AhR activation and elevation of ethoxyresorufin O-deethylase activity in the liver, whereas the teas themselves did not induce them. Tea showed a suppressive fashion on the expression of cytochrome P450 1A1 (CYP1A1). Tea suppressed the AhR activation induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) ex vivo. A part of catechins and theaflavins was present in plasma and liver as conjugated and intact forms. The results of this study suggested that active component(s) of tea are incorporated in the liver and suppress the activity of CYP1As through the AhR activation pathway.
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Affiliation(s)
- Itsuko Fukuda
- Research Center for Food Safety and Security, Graduate School of Agricultural Science, Kobe University , Hyogo , Japan and
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17
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Fatokun AA, Tome M, Smith RA, Darlington LG, Stone TW. Protection by the flavonoids quercetin and luteolin against peroxide- or menadione-induced oxidative stress in MC3T3-E1 osteoblast cells. Nat Prod Res 2014; 29:1127-32. [DOI: 10.1080/14786419.2014.980252] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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18
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Inhibition of P-Glycoprotein Enhances the Suppressive Effect of Kaempferol on Transformation of the Aryl Hydrocarbon Receptor. Biosci Biotechnol Biochem 2014; 73:1635-9. [DOI: 10.1271/bbb.90145] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Hiura Y, Satsu H, Hamada M, Shimizu M. Analysis of flavonoids regulating the expression of UGT1A1 via xenobiotic receptors in intestinal epithelial cells. Biofactors 2014; 40:336-45. [PMID: 24375494 DOI: 10.1002/biof.1153] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 11/11/2013] [Indexed: 12/23/2022]
Abstract
UDP-glucuronosyltransferase (UGT) 1A1 is one of the major metabolic enzymes for the detoxification of harmful xenobiotics in intestines, and its expression is regulated by transcription factors like the aryl hydrocarbon receptor (AhR) and the pregnane X receptor (PXR). A screening assay using real-time PCR showed that baicalein and 3-hydroxyflavone induced human UGT1A1 mRNA expression in LS180 cells. Experimental results confirmed that these flavonoids increased UGT1A protein expression as well as its enzymatic activity. The results indicated that baicalein and 3-hydroxyflavone increased the transcriptional activity of UGT1A1 via AhR and PXR, respectively. Observation via immunofluorescence microscopy suggested that baicalein and 3-hydroxyflavone further induced nuclear translocation of AhR and PXR, respectively. In addition, direct interaction between baicalein and AhR or 3-hydroxyflavone and PXR were observed using the quartz crystal microbalance method. These results elucidate the molecular mechanism of flavonoid-induced UGT1A1 gene expression via xenobiotic receptors in the intestines.
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Affiliation(s)
- Yuto Hiura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
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Wang Y, Xu YS, Yin LH, Xu LN, Peng JY, Zhou H, Kang W. Synergistic anti-glioma effect of Hydroxygenkwanin and Apigenin in vitro. Chem Biol Interact 2013; 206:346-55. [PMID: 24144774 DOI: 10.1016/j.cbi.2013.10.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 10/07/2013] [Accepted: 10/09/2013] [Indexed: 02/01/2023]
Abstract
Apigenin (AP) and Hydroxygenkwanin (HGK) are two natural flavonoid compounds. Previous studies have already demonstrated the anti-tumor capability of AP. However, it is not clear whether HGK has such property. In the current study, the anti-glioma activities of HGK and its synergistic anti-glioma effects with AP on C6 glioma cells were investigated. In addition, the possible mechanisms were also studied. MTT assay and morphologic analysis including acridine orange/ethidium bromide (AO/EB) and 4',6-diamidino-2-phenylindole (DAPI) staining were used in the research, and the results indicated that the treatment with AP or HGK could inhibit C6 glioma cell proliferation respectively. Moreover, when AP was administrated simultaneously, the anti-glioma effect of HGK was dramatically enhanced in a dose-dependent manner, which is obviously better than that of carmustine (BCNU) at the concentration 25μM for treating of 24h. Compared with control, mitochondrial membrane potential (MPP) loss and mitochondrion damage were detected by JC-1 fluorescence probes (JC-1) and transmission electron microscopy (TEM) after treatment. Obvious DNA damage and cell cycle S phase arrest were detected by alkaline comet assay and flow cytometric analysis (FCM). Additionally, up regulation of TNF-α level, activations of caspase-3, -8, over expressions of BID and BAK protein and BCL-XL protein down expression were also observed after treatment by the combination of AP and HGK. The results indicate that HGK may be an effective natural product to treat glioma, and the combination of AP and HGK may be a promising method for glioma chemotherapy.
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Affiliation(s)
- Yi Wang
- Department of Neurosurgery, 1st Affiliated Hospital of Dalian Medical University, No. 222, Dalian Zhongshan Road, Dalian 116011, Liaoning, China
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EGCG protects endothelial cells against PCB 126-induced inflammation through inhibition of AhR and induction of Nrf2-regulated genes. Toxicol Appl Pharmacol 2012; 261:181-8. [PMID: 22521609 DOI: 10.1016/j.taap.2012.03.024] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 03/30/2012] [Indexed: 12/17/2022]
Abstract
Tea flavonoids such as epigallocatechin gallate (EGCG) protect against vascular diseases such as atherosclerosis via their antioxidant and anti-inflammatory functions. Persistent and widespread environmental pollutants, including polychlorinated biphenyls (PCB), can induce oxidative stress and inflammation in vascular endothelial cells. Even though PCBs are no longer produced, they are still detected in human blood and tissues and thus considered a risk for vascular dysfunction. We hypothesized that EGCG can protect endothelial cells against PCB-induced cell damage via its antioxidant and anti-inflammatory properties. To test this hypothesis, primary vascular endothelial cells were pretreated with EGCG, followed by exposure to the coplanar PCB 126. Exposure to PCB 126 significantly increased cytochrome P450 1A1 (Cyp1A1) mRNA and protein expression and superoxide production, events which were significantly attenuated following pretreatment with EGCG. Similarly, EGCG also reduced DNA binding of NF-κB and downstream expression of inflammatory markers such as monocyte chemotactic protein-1 (MCP-1) and vascular cell adhesion protein-1 (VCAM-1) after PCB exposure. Furthermore, EGCG decreased endogenous or base-line levels of Cyp1A1, MCP-1 and VCAM-1 in endothelial cells. Most of all, treatment of EGCG upregulated expression of NF-E2-related factor 2 (Nrf2)-controlled antioxidant genes, including glutathione S transferase (GST) and NAD(P)H:quinone oxidoreductase 1 (NQO1), in a dose-dependent manner. In contrast, silencing of Nrf2 increased Cyp1A1, MCP-1 and VCAM-1 and decreased GST and NQO1 expression, respectively. These data suggest that EGCG can inhibit AhR regulated genes and induce Nrf2-regulated antioxidant enzymes, thus providing protection against PCB-induced inflammatory responses in endothelial cells.
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Hara K, Ohara M, Hayashi I, Hino T, Nishimura R, Iwasaki Y, Ogawa T, Ohyama Y, Sugiyama M, Amano H. The green tea polyphenol (−)-epigallocatechin gallate precipitates salivary proteins including alpha-amylase: biochemical implications for oral health. Eur J Oral Sci 2012; 120:132-9. [DOI: 10.1111/j.1600-0722.2012.00947.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Chen PH, Chang H, Chang JT, Lin P. Aryl hydrocarbon receptor in association with RelA modulates IL-6 expression in non-smoking lung cancer. Oncogene 2011; 31:2555-65. [PMID: 21996739 DOI: 10.1038/onc.2011.438] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that is activated by cigarette smoke. Previously, we demonstrated that AhR is overexpressed in lung adenocarcinomas (ADs). In this study we observed that AhR expression is significantly correlated with nuclear RelA (a nuclear factor-κB (NFκB) subunit) and cytosolic interleukin-6 (IL-6) in 200 non-small cell lung cancer patients, especially among never smokers. Overexpression of AhR increased IL-6 expression in H1355 cells and immortalized human bronchial epithelial cells BEAS-2B. As NFκB inhibitor and knockdown RelA expression greatly reduced constitutive AhR-induced IL-6 expression, we hypothesized that AhR expression, in the absence of exogenous ligand, is able to modulate NFκB activity and subsequently upregulate IL-6 expression, thus promoting the development of lung AD. Specifically, AhR overexpression significantly increased NFκB activity, whereas interference with AhR expression significantly reduced NFκB activity and IL-6 expression in H1355 cells. We demonstrated that AhR associates with RelA in the cytosol and nucleus of human lung cells. Furthermore, AhR overexpression enhanced nuclear localization of AhR and RelA, and increased the association of AhR-RelA with the NFκB response element of the IL-6 promoter. However, p50 was not involved. Our results indicate that AhR, without exposure to a ligand, associates with RelA, which then positively modulates NFκB activity and then upregulates IL-6 expression in human lung cells. Thus we have identified a new mechanism for lung tumorigenesis in non-smokers.
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Affiliation(s)
- P-H Chen
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
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Dvorak Z, Pavek P. Regulation of drug-metabolizing cytochrome P450 enzymes by glucocorticoids. Drug Metab Rev 2011; 42:621-35. [PMID: 20482443 DOI: 10.3109/03602532.2010.484462] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The regulation of drug-metabolizing cytochrome P450 enzymes (CYP) is a complex process involving multiple mechanisms. Among them, transcriptional regulation through ligand-activated nuclear receptors is the crucial mechanism involved in hormone-controlled and xenobiotic-induced expression of drug-metabolizing CYPs. In this article, we focus, in detail, on the role of the glucocorticoid receptor (GR) in the transcriptional regulation of human drug-metabolizing CYP enzymes and the mechanisms of the regulation. There are at least three distinct transcriptional mechanisms by which GR controls the expression of CYPs: 1) direct binding of GR to a specific gene-promoter sequence called the glucocorticoid responsive element (GRE); 2) indirect binding of GR in the form of a multiprotein complex to gene promoters without a direct contact between GR and promoter DNA; and 3) up- or downregulation of other CYP transcriptional regulators or nuclear receptors (i.e., transcriptional regulatory cross-talk). However, due to the general effect of glucocorticoids on numerous cellular pathways and functions, the net transcriptional effect of glucocorticoids on drug-metabolizing enzymes is usually a combination of several mechanisms. Since synthetic glucocorticoids are widely prescribed in human pharmacotherapy for the treatment of many diseases, comprehensive understanding of the transcriptional regulation of drug-metabolizing CYPs via GR with respect to glucocorticoid therapy or glucocorticoid hormonal status will aid in the development of efficient individualized pharmacotherapy without drug-drug interactions.
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Affiliation(s)
- Zdenek Dvorak
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Olomouc, Czech Republic.
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Barreiro KA, Di Yorio MP, Artillo-Guida RD, Paz DA, Faletti AG. Daily treatment with α-naphthoflavone enhances follicular growth and ovulation rate in the rat. Toxicol Appl Pharmacol 2011; 252:11-7. [DOI: 10.1016/j.taap.2011.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2010] [Revised: 01/12/2011] [Accepted: 01/13/2011] [Indexed: 10/18/2022]
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26
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Bouchez LC, Boitano AE, de Lichtervelde L, Romeo R, Cooke MP, Schultz PG. Small-molecule regulators of human stem cell self-renewal. Chembiochem 2011; 12:854-7. [PMID: 21381174 DOI: 10.1002/cbic.201000734] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Indexed: 01/07/2023]
Affiliation(s)
- Laure C Bouchez
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA-92037, (USA)
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27
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Uchi H, Tokunaga S, Mitoma C, Shibata S, Hamada N, Nakanishi Y, Kajiwara J, Yoshimura T, Furue M. A clinical trial of kampo formulae for the treatment of symptoms of yusho, a poisoning caused by dioxins and related organochlorine compounds. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2011; 2011:589724. [PMID: 19996156 PMCID: PMC3136710 DOI: 10.1093/ecam/nep209] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 11/12/2009] [Indexed: 11/29/2022]
Abstract
The objective of this study was to evaluate the effectiveness of traditional herbal medicines (Kampo) on the symptoms of Yusho. Yusho is a mass food poisoning that was caused by ingestion of rice oil contaminated with dioxins and related organochlorines in 1968. Patients with Yusho suffer from skin symptoms (acneform eruptions, liability to suppuration and pigmentation), respiratory symptoms (cough and expectoration of sputum), neurological symptoms (numbness and paresthesia of extremities), arthralgia and general fatigue, and no effective treatment has yet been developed. In this clinical trial, four Kampo formulae (Bakumondo-to, Keigai-rengyo-to, Gosha-jinki-gan and Hochu-ekki-to) were administered to four representative Yusho symptoms (respiratory, skin, neurological symptoms and general fatigue), respectively. Twenty-seven Yusho patients were enrolled and two formulae were administered to each patient for half-a-year each. The effectiveness of Kampo formulae was estimated by changes in the intensity of symptoms measured by a visual analogue scale (VAS) of 100 mm recorded at baseline and after administration of each formula. The influence of Kampo formulae on patients' quality of life (QOL) was also assessed by the SF-36 (NBS). Twenty-five patients completed the treatment. Bakumondo-to significantly improved respiratory symptoms as well as patients' QOL in the context of vitality, compared with other formulae. In contrast, Hochu-ekki-to impaired patients' QOL in the context of physical functioning and vitality, compared with other formulae. This study demonstrated for the first time that a Kampo formula Bakumondo-to is useful for treating respiratory symptoms caused by dioxins.
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Affiliation(s)
- Hiroshi Uchi
- Research and Clinical Center for Yusho and Dioxin, Kyushu University Hospital, Fukuoka 812-8582, Japan
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Mukai R, Shirai Y, Saito N, Fukuda I, Nishiumi S, Yoshida KI, Ashida H. Suppression mechanisms of flavonoids on aryl hydrocarbon receptor-mediated signal transduction. Arch Biochem Biophys 2010; 501:134-41. [PMID: 20450880 DOI: 10.1016/j.abb.2010.05.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 04/23/2010] [Accepted: 05/01/2010] [Indexed: 10/19/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates biological and toxicological effects by binding to its agonists such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Previously we demonstrated that flavonoids suppressed the TCDD-induced DNA-binding activity of the AhR in a structure-dependent manner. In this study, we investigated the mechanisms by which flavonoids suppressed the AhR-mediated signal transduction in mouse hepatoma Hepa-1c1c7 cells. Flavones and flavonols suppressed the TCDD-induced nuclear translocation of the AhR and dissociation of its partner proteins, heat shock protein 90 and X-associated protein 2, whereas flavanones and catechins did not. Flavonoids of all these four subclasses suppressed the phosphorylation of both AhR and Arnt and the formation of a heterodimer consisting of these proteins. Since certain flavonoids are known to inhibit mitogen-activated protein kinases (MAPKs), we confirmed the contribution of MAPK/ERK kinase (MEK) to the AhR-mediated signal transduction by using U0126, an inhibitor of MEK1/2. U0126 suppressed TCDD-induced phosphorylation of the AhR and Arnt followed by the DNA-binding activity of the AhR. Flavanones and catechins suppressed the TCDD-induced phosphorylation of ERK1/2. The inhibition of MEK/ERK phosphorylation is one of the mechanisms by which flavanones and catechins suppress the AhR-mediated signal transduction in Hepa-1c1c7 cells.
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Affiliation(s)
- Rie Mukai
- Department of Agrobioscience, School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
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Potential health-modulating effects of isoflavones and metabolites via activation of PPAR and AhR. Nutrients 2010; 2:241-79. [PMID: 22254019 PMCID: PMC3257647 DOI: 10.3390/nu2030241] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 02/23/2010] [Indexed: 12/24/2022] Open
Abstract
Isoflavones have multiple actions on cell functions. The most prominent one is the activation of estrogen receptors. Other functions are often overlooked, but are equally important and explain the beneficial health effects of isoflavones. Isoflavones are potent dual PPARα/γ agonists and exert anti-inflammatory activity, which may contribute to the prevention of metabolic syndrome, atherosclerosis and various other inflammatory diseases. Some isoflavones are potent aryl hydrocarbon receptor (AhR) agonists and induce cell cycle arrest, chemoprevention and modulate xenobiotic metabolism. This review discusses effects mediated by the activation of AhR and PPARs and casts a light on the concerted action of isoflavones.
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DuSell CD, Nelson ER, Wittmann BM, Fretz JA, Kazmin D, Thomas RS, Pike JW, McDonnell DP. Regulation of aryl hydrocarbon receptor function by selective estrogen receptor modulators. Mol Endocrinol 2009; 24:33-46. [PMID: 19901195 DOI: 10.1210/me.2009-0339] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Selective estrogen receptor modulators (SERMs), such as tamoxifen (TAM), have been used extensively for the treatment and prevention of breast cancer and other pathologies associated with aberrant estrogen receptor (ER) signaling. These compounds exhibit cell-selective agonist/antagonist activities as a consequence of their ability to induce different conformational changes in ER, thereby enabling it to recruit functionally distinct transcriptional coregulators. However, the observation that SERMs can also regulate aspects of calcium signaling and apoptosis in an ER-independent manner in some systems suggests that some of the activity of drugs within this class may also arise as a consequence of their ability to interact with targets other than ER. In this study, we demonstrate that 4-hydroxy-TAM (4OHT), an active metabolite of TAM, directly binds to and modulates the transcriptional activity of the aryl hydrocarbon receptor (AHR). Of specific interest was the observation, that in the absence of ER, 4OHT can induce the expression of AHR target genes involved in estradiol metabolism, cellular proliferation, and metastasis in cellular models of breast cancer. The potential role for AHR in SERM pharmacology was further underscored by the ability of 4OHT to suppress osteoclast differentiation in vitro in part through AHR. Cumulatively, these findings provide evidence that it is necessary to reevaluate the relative roles of ER and AHR in manifesting the pharmacological actions and therapeutic efficacy of TAM and other SERMs.
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Affiliation(s)
- Carolyn D DuSell
- Duke University Medical Center, Department of Pharmacology and Cancer Biology, Durham, North Carolina 27710, USA
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Androutsopoulos VP, Li N, Arroo RRJ. The methoxylated flavones eupatorin and cirsiliol induce CYP1 enzyme expression in MCF7 cells. JOURNAL OF NATURAL PRODUCTS 2009; 72:1390-1394. [PMID: 19601638 DOI: 10.1021/np900051s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Flavonoids have often been associated with cancer prevention and activity of the human cytochrome P450 enzymes CYP1A1 and CYP1B1 with the occurrence of cancer. The flavones eupatorin (1) and cirsiliol (2) enhanced CYP1 enzyme activity in a concentration-dependent manner in MCF7 human breast adenocarcinoma cells. In the range of 0-2.5 microM, 2 caused a dose-dependent increase in CYP1B1 mRNA levels and an increase in CYP1A1 mRNA. Compound 1 caused an increase in CYP1A1 and CYP1B1 mRNA at higher doses (approximately 5 microM). Both CYP1B1 and CYP1A1 catalyzed the conversion of 2 into an as yet unidentified compound. Application of the CYP1 family inhibitor, acacetin, significantly increased the IC(50) value of 2 in MCF7 cells, but did not significantly affect the action of 1. The data suggest that 2 induces CYP1 enzyme expression in cancer cells and is subsequently converted by CYP1B1 or CYP1A1 into an antiproliferative agent.
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Affiliation(s)
- Vasilis P Androutsopoulos
- Laboratory of Forensic Sciences and Toxicology, University of Crete, Heraklion, Voutes 71003, Greece.
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Matsumoto S, Jin M, Dewa Y, Nishimura J, Moto M, Murata Y, Shibutani M, Mitsumori K. Suppressive effect of Siraitia grosvenorii extract on dicyclanil-promoted hepatocellular proliferative lesions in male mice. J Toxicol Sci 2009; 34:109-18. [PMID: 19182440 DOI: 10.2131/jts.34.109] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Dicyclanil (DC) generates reactive oxygen species (ROS) due to Cyp1a1 induction, and DNA damage caused by oxidative stress is probably involved in hepatocarcinogenesis in mice. To clarify the modifying effect of the Siraitia grosvenorii extract (SGE), which has antioxidative properties, we employed a 2-stage liver carcinogenesis model in partially hepatectomized male ICR mice. Mice maintained on diet containing DC at a concentration of 1,500 ppm for 9 weeks after a single intraperitoneal injection of diethylnitrosamine (DEN) at a dose of 30 mg/kg and they were given water containing 2,500 ppm of SGE for 11 weeks including 2 weeks as pre-administration on DC. SGE inhibited the induction of gamma-glutamyltranspeptidase-positive hepatocytes, lipid peroxidation, and gene expression of Cyp1a1, all of which were caused by DC. To examine whether SGE indirectly inhibits Cyp1a1 expression induced by inhibition of aryl hydrocarbon receptor (Ahr)-mediated signal transduction caused by DC, mice with high (C57BL/6J mice) and low affinities (DBA/2J mice) to Ahr were given DC-containing diet and/or SGE-containing tap water for 2 weeks. Cyp1a1 gene expression was significantly lower in C57BL/6J mice administered DC + SGE than in C57BL/6J mice administered DC alone; there was no difference in the Cyp1a1 expression between DBA/2J mice administered DC + SGE and DC alone. These results suggest that SGE suppresses the induction of Cyp1a1, leading to inhibition of ROS generation and consequently inhibited hepatocarcinogenesis, probably due to suppression of Ahr activity.
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Affiliation(s)
- Sayaka Matsumoto
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
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Abstract
The skin is the largest organ of the body and protects the organism against external physical, chemical and biological insults, such as wounding, ultraviolet radiation and micro-organisms. The epidermis is the upper part of the skin that is continuously renewed. The keratinocytes are the major cell type in the epidermis and undergo a specialized form of programmed cell death, called cornification, which is different from classical apoptosis. In keep with this view, several lines of evidence indicate that NF-kB is an important factor providing protection against keratinocyte apoptosis in homeostatic and inflammatory conditions. In contrast, the hair follicle is an epidermal appendage that shows cyclic apoptosis-driven involution, as part of the normal hair cycle. The different cell death programs need to be well orchestrated to maintain skin homeostasis. One of the major environmental insults to the skin is UVB radiation, causing the occurrence of apoptotic sunburn cells. Deregulation of cell death mechanisms in the skin can lead to diseases such as cancer, necrolysis and graft-versus-host disease. Here we review the apoptotic and the anti-apoptotic mechanisms in skin homeostasis and disease.
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34
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Rich RL, Myszka DG. Survey of the year 2007 commercial optical biosensor literature. J Mol Recognit 2008; 21:355-400. [DOI: 10.1002/jmr.928] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Ashida H, Nishiumi S, Fukuda I. An update on the dietary ligands of the AhR. Expert Opin Drug Metab Toxicol 2008; 4:1429-47. [DOI: 10.1517/17425255.4.11.1429] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Food flavonoid aryl hydrocarbon receptor-mediated agonistic/antagonistic/synergic activities in human and rat reporter gene assays. Anal Chim Acta 2008; 637:337-45. [PMID: 19286049 DOI: 10.1016/j.aca.2008.09.054] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2008] [Revised: 09/24/2008] [Accepted: 09/24/2008] [Indexed: 02/01/2023]
Abstract
Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor mediating the adverse effects of dioxins and polycyclic aromatic hydrocarbons (PAHs). In this study, we investigated the genetic-, time-, dose-, species- and tissue-dependent AhR-mediated agonistic/antagonistic activities of three food flavonoids: quercetin, chrysin and genistein. To that end, four stably transfected cell lines were used in cell-based luciferase reporter gene assays: three lines were transformed with the ptKLuc vector harbouring four dioxin-responsive elements (DREs) upstream of the thymidine kinase promoter and the luciferase gene (HepG2-Luc, T-47D-Luc and H4IIE-ULg). The fourth is a patented cell line transformed with a different construct: H4IIE DR-CALUX((R)). Both H4IIE cells were compared for their genetic construction. Human hepatoma (HepG2-Luc) and human breast tumour (T-47D-Luc) cells were compared for tissue-dependent effects. Rat hepatoma (H4IIE-ULg) and human hepatoma (HepG2-Luc) cells were compared for species-dependent activities. We concluded that quercetin, chrysin and genistein act in a time-, dose-, species- and tissue-specific way. For example, genistein displayed agonistic activities when exposed to rat hepatoma cells during 6h but not after 24h. Flavonoids displayed agonistic/antagonistic activities in human breast tumour cells, depending on the exposure time, while in human hepatoma cells, only antagonistic activities of flavonoids were measured. In addition, we report, in all the cells, a synergy between an isoflavone and two food contaminants; the 2,3,7,8-tetrachlorodibenzo-p-dioxin and 3-methylcholanthrene, a PAH. In rat cells, this synergy occurred when cells were exposed to flavonoids and contaminant for 6h, while it was observed in human cells only after 24h.
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Murakami A, Ashida H, Terao J. Multitargeted cancer prevention by quercetin. Cancer Lett 2008; 269:315-25. [PMID: 18467024 DOI: 10.1016/j.canlet.2008.03.046] [Citation(s) in RCA: 461] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 01/31/2008] [Accepted: 03/28/2008] [Indexed: 02/07/2023]
Abstract
Quercetin is an anti-oxidative flavonoid widely distributed in the plant kingdom. Phenolic hydroxyl groups at the B-ring and the 3-position are responsible for its free radical-scavenging activity. Quercetin is commonly present as a glycoside and is converted to glucuronide/sulfate conjugates during intestinal absorption and only conjugated metabolites are therefore found in circulating blood. Although metabolic conversion attenuates its biological effects, active aglycone may be generated from the glucuronide conjugates by enhanced beta-glucuronidase activity during inflammation. With respect to its relationship with molecular targets relevant to cancer prevention, quercetin aglycone has been shown to interact with some receptors, particularly an aryl hydrocarbon receptor, which is involved in the development of cancers induced by certain chemicals. Quercetin aglycone has also been shown to modulate several signal transduction pathways involving MEK/ERK and Nrf2/keap1, which are associated with the processes of inflammation and carcinogenesis. Rodent studies have demonstrated that dietary administration of this flavonol prevents chemically induced carcinogenesis, especially in the colon, whilst epidemiological studies have indicated that an intake of quercetin may be associated with the prevention of lung cancer. Dietary quercetin is, therefore, a promising agent for cancer prevention and further research is warranted.
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Affiliation(s)
- Akira Murakami
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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Kampkötter A, Wiegand C, Timpel C, Röhrdanz E, Chovolou Y, Kahl R, Wätjen W. Increased expression of catalase in human hepatoma cells by the soy isoflavone, daidzein. Basic Clin Pharmacol Toxicol 2008; 102:437-42. [PMID: 18047476 DOI: 10.1111/j.1742-7843.2007.00173.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The reduced incidence of cancer that has been observed in Asian population traditionally consuming soy-based food has been linked to the antioxidant potential of soy isoflavones, in particular daidzein and genistein. The present study was undertaken in order to test the antioxidative potential of daidzein and to examine the effect of daidzein treatment on the expression of the antioxidant enzyme catalase in the human hepatoma cell lines Huh-7 and HepG2. Daidzein itself did not display radical scavenging activity but it significantly increased the activity of the antioxidant enzyme catalase. Huh-7 cells were much more susceptible to daidzein cytotoxicity than HepG2 cells and showed much lower basal activity in luciferase reporter gene assays with the 3.2 kb fragment of the human catalase promoter. However, treatment with daidzein at a non-toxic concentration resulted in a similar induction of promoter activity in both cell lines. Reporter gene studies with different promoter constructs in HepG2 cells restrict the potential localization of the main regulatory elements for basal and inducible activity of the catalase promoter to a region approximately 120 bp to 300 bp upstream of the start codon of the catalase gene. From our results, we conclude that in human hepatoma cells daidzein at a non-toxic concentration increases the activity of human catalase and induces the transcription of the catalase gene via interaction with the proximal part of the promoter.
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Affiliation(s)
- Li Zhang
- School of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Hong Kong, SAR, and Department of Pharmacology,
Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong,
SAR
| | - Zhong Zuo
- School of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Hong Kong, SAR, and Department of Pharmacology,
Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong,
SAR
| | - Ge Lin
- School of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Hong Kong, SAR, and Department of Pharmacology,
Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong,
SAR
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Agostinis P, Garmyn M, Van Laethem A. The Aryl hydrocarbon receptor: an illuminating effector of the UVB response. ACTA ACUST UNITED AC 2007; 2007:pe49. [PMID: 17848686 DOI: 10.1126/stke.4032007pe49] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a cytosolic ligand-activated transcription factor that mediates most of the toxic and carcinogenic effects of drugs and environmental toxins collectively known as xenobiotics. Ligand activation of the AhR stimulates the transcription of genes that encode several xenobiotic-metabolizing enzymes. The molecular mechanisms and signaling pathways evoked by the activation of the AhR are becoming increasingly understood and underscore the participation of the AhR in crucial processes, including cellular stress response, proliferation, differentiation, inflammation, and carcinogenesis. Studies now implicate the AhR as an integral part of the multifaceted signal transduction pathway initiated by the exposure of keratinocytes to ultraviolet B radiation (UVB), which is the most ubiquitous hazard to human skin and the principal risk factor for skin cancer. Ligand-dependent activation of the AhR in the cytosol provides a molecular bridge that links cytoplasmic events to nuclear signals, thus unmasking a previously unknown role for this transcription factor in the complex cellular response to UVB.
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Affiliation(s)
- Patrizia Agostinis
- Department of Molecular and Cell Biology, Faculty of Medicine, Catholic University of Leuven, Belgium.
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