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Poschner S, Maier-Salamon A, Thalhammer T, Jäger W. Resveratrol and other dietary polyphenols are inhibitors of estrogen metabolism in human breast cancer cells. J Steroid Biochem Mol Biol 2019; 190:11-18. [PMID: 30851384 DOI: 10.1016/j.jsbmb.2019.03.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/26/2019] [Accepted: 03/01/2019] [Indexed: 01/09/2023]
Abstract
Polyphenols in foods and dietary supplements are commonly used for the prevention and treatment of a variety of malignancies, including breast cancer. However, daily intake by patients with breast cancer is controversial, as these compounds may stimulate cancer growth. Estrogens serve key roles in breast cancer cell proliferation; therefore, understanding the interaction between endogenous steroid hormones and natural dietary polyphenols is essential. Currently, comprehensive knowledge regarding these effects remains limited. The current review summarizes the dose-dependent in vitro and in vivo interactions of resveratrol and other dietary polyphenols with estrogen precursors, active estrogens, catechol estrogens and their respective glucuronidated, sulfated, glutathionated or O-methylated metabolites in estrogen receptor alpha negative (ERα-) and positive (ERα+) breast cancer. Which estrogen-metabolizing enzymes are affected by polyphenols is also reviewed in detail. Furthermore, the impacts of dose and therapy duration on disease development and progression in patients with breast cancer are discussed. The present article is part of a Special Issue titled 'CSR 2018'.
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Affiliation(s)
- Stefan Poschner
- Department of Pharmaceutical Chemistry, Division of Clinical Pharmacy and Diagnostics, University of Vienna, 1090 Vienna, Austria
| | - Alexandra Maier-Salamon
- Department of Pharmaceutical Chemistry, Division of Clinical Pharmacy and Diagnostics, University of Vienna, 1090 Vienna, Austria
| | - Theresia Thalhammer
- Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Walter Jäger
- Department of Pharmaceutical Chemistry, Division of Clinical Pharmacy and Diagnostics, University of Vienna, 1090 Vienna, Austria; Vienna Metabolomics Center (VIME), University of Vienna, Austria.
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Poschner S, Maier-Salamon A, Zehl M, Wackerlig J, Dobusch D, Meshcheryakova A, Mechtcheriakova D, Thalhammer T, Pachmann B, Jäger W. Resveratrol Inhibits Key Steps of Steroid Metabolism in a Human Estrogen-Receptor Positive Breast Cancer Model: Impact on Cellular Proliferation. Front Pharmacol 2018; 9:742. [PMID: 30042681 PMCID: PMC6048268 DOI: 10.3389/fphar.2018.00742] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 06/19/2018] [Indexed: 12/12/2022] Open
Abstract
The role of resveratrol (RES) in preventing breast cancer is controversial, as low concentrations may stimulate the proliferation of estrogen-receptor alpha positive (ERα+) breast cancer cells. As metabolism is the key factor in altering cellular estrogens, thereby influencing breast tumor growth, we investigated the effects of RES on the formation of estrogen metabolites, namely 4-androstene-3,17-dione (AD), dehydroepiandrosterone (DHEA), dehydroepiandrosterone-3-O-sulfate (DHEA-S), estrone (E1), estrone-3-sulfate (E1-S), 17β-estradiol (E2), 17β-estradiol-3-O-(β-D-glucuronide) (E2-G), 17β-estradiol-3-O-sulfate (E2-S), 16α-hydroxy-17β-estradiol (estriol, E3), and testosterone (T) in ERα- MDA-MB-231 and ERα+ MCF-7 cells. Incubation of both of the cell lines with the hormone precursors DHEA and E1 revealed that sulfation and glucuronidation were preferred metabolic pathways for DHEA, E1 and E2 in MCF-7 cells, compared with in MDA-MB-231 cells, as the Vmax values were significantly higher (DHEA-S: 2873.0 ± 327.4 fmol/106 cells/h, E1-S: 30.4 ± 2.5 fmol/106 cells/h, E2-S: 24.7 ± 4.9 fmol/106 cells/h, E2-G: 7.29 ± 1.36 fmol/106 cells/h). RES therefore significantly inhibited DHEA-S, E1-S, E2-S and E2-G formation in MCF-7, but not in MDA-MB-231 cells (Kis: E2-S, 0.73 ± 0.07 μM < E1-S, 0.94 ± 0.03 μM < E2-G, 7.92 ± 0.24 μM < DHEA-S, 13.2 ± 0.2 μM). Suppression of these metabolites subsequently revealed twofold higher levels of active E2, concomitant with an almost twofold increase in MCF-7 cell proliferation, which was the most pronounced upon the addition of 5 μM RES. As the content of RES in food is relatively low, an increased risk of breast cancer progression in women is likely to only be observed following the continuous consumption of high-dose RES supplements. Further long-term human studies simultaneously monitoring free estrogens and their conjugates are therefore highly warranted to evaluate the efficacy and safety of RES supplementation, particularly in patients diagnosed with ERα+ breast cancer.
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Affiliation(s)
- Stefan Poschner
- Division of Clinical Pharmacy and Diagnostics, Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Alexandra Maier-Salamon
- Division of Clinical Pharmacy and Diagnostics, Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Martin Zehl
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Judith Wackerlig
- Division of Drug Design and Medicinal Chemistry, Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Daniel Dobusch
- Division of Drug Design and Medicinal Chemistry, Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Anastasia Meshcheryakova
- Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Diana Mechtcheriakova
- Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Theresia Thalhammer
- Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Bettina Pachmann
- Division of Clinical Pharmacy and Diagnostics, Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Walter Jäger
- Division of Clinical Pharmacy and Diagnostics, Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria.,Vienna Metabolomics Center, University of Vienna, Vienna, Austria
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Park YJ, Ahn HY, Kim HR, Chung KH, Oh SM. Ginkgo biloba extract EGb 761-mediated inhibition of aromatase for the treatment of hormone-dependent breast cancer. Food Chem Toxicol 2016; 87:157-65. [DOI: 10.1016/j.fct.2015.12.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 11/30/2015] [Accepted: 12/04/2015] [Indexed: 12/22/2022]
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Go RE, Hwang KA, Choi KC. Cytochrome P450 1 family and cancers. J Steroid Biochem Mol Biol 2015; 147:24-30. [PMID: 25448748 DOI: 10.1016/j.jsbmb.2014.11.003] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/28/2014] [Accepted: 11/03/2014] [Indexed: 02/07/2023]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcriptional factor that dimerizes with aryl hydrocarbon receptor nuclear translocator (ARNT). This complex binds to xenobiotics response element (XREs), and then starts the expressions of downstream genes including cytochrome P450 (CYP) 1 family members: CYP1A1, CYP1A2 and CYP1B1. Role of CYP1 family is involved in the metabolism of endogenous hormones, xenobiotics and drug. The expression of CYP1 family is regulated by estradiol (E2) or xenobiotics in diverse cancers. In breast cancers expressing estrogen receptors (ERs), level of CYP1B1 is increased by E2 and reversed by an estrogen receptor antagonist, ICI 182,780 or 4-hydrotamoxifen, which indicates that the expression of CYP1 family in downstream region of AhR is regulated by an activation of ERα. In metabolic pathways, E2 is converted into 4-hydroxyestradiol by CYP1B1, which can be converted into mainly estradiol-3,4-quinone, a potential carcinogen, by peroxidase. Increased expression of CYP1 family indicates the possibility of carcinogenesis by exposure of xenobiotics in endometrial and ovarian cancers. Apart from roles of CYP1 family in relation with ER pathway, CYP1 family is over-expressed in ER independent cancers. CYP1A1 exhibits hydroxylase activity in oxidation of arachidonic acid, which has been transformed to 12(R)-hydrxyeicosatetraenoic (HETEs), a potent activator of AhR activity. On the basis of results, phytoestrogens and dexamethasone are provided as cancer therapy regulating the expression of CYP1 family. Thus, this review focuses on the role(s) of CYP1 family in ER-dependent or ER-independent cancers and the potential for cancer therapy to target CYP1 family in these cancers.
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Affiliation(s)
- Ryeo-Eun Go
- Laboratory of Biochemistry and Immunology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763,Republic of Korea
| | - Kyung-A Hwang
- Laboratory of Biochemistry and Immunology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763,Republic of Korea
| | - Kyung-Chul Choi
- Laboratory of Biochemistry and Immunology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763,Republic of Korea.
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Murakami I, Chaleckis R, Pluskal T, Ito K, Hori K, Ebe M, Yanagida M, Kondoh H. Metabolism of skin-absorbed resveratrol into its glucuronized form in mouse skin. PLoS One 2014; 9:e115359. [PMID: 25506824 PMCID: PMC4266648 DOI: 10.1371/journal.pone.0115359] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 11/22/2014] [Indexed: 01/24/2023] Open
Abstract
Resveratrol (RESV) is a plant polyphenol, which is thought to have beneficial metabolic effects in laboratory animals as well as in humans. Following oral administration, RESV is immediately catabolized, resulting in low bioavailability. This study compared RESV metabolites and their tissue distribution after oral uptake and skin absorption. Metabolomic analysis of various mouse tissues revealed that RESV can be absorbed and metabolized through skin. We detected sulfated and glucuronidated RESV metabolites, as well as dihydroresveratrol. These metabolites are thought to have lower pharmacological activity than RESV. Similar quantities of most RESV metabolites were observed 4 h after oral or skin administration, except that glucuronidated RESV metabolites were more abundant in skin after topical RESV application than after oral administration. This result is consistent with our finding of glucuronidated RESV metabolites in cultured skin cells. RESV applied to mouse ears significantly suppressed inflammation in the TPA inflammation model. The skin absorption route could be a complementary, potent way to achieve therapeutic effects with RESV.
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Affiliation(s)
- Itsuo Murakami
- Geriatric unit, Kyoto University Hospital, Sakyo-ku, Kyoto, Japan
| | - Romanas Chaleckis
- Geriatric unit, Kyoto University Hospital, Sakyo-ku, Kyoto, Japan
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna-son, Okinawa, Japan
| | - Tomáš Pluskal
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna-son, Okinawa, Japan
| | - Ken Ito
- Geriatric unit, Kyoto University Hospital, Sakyo-ku, Kyoto, Japan
| | - Kousuke Hori
- Geriatric unit, Kyoto University Hospital, Sakyo-ku, Kyoto, Japan
| | - Masahiro Ebe
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna-son, Okinawa, Japan
| | - Mitsuhiro Yanagida
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna-son, Okinawa, Japan
- * E-mail: (HK); (MY)
| | - Hiroshi Kondoh
- Geriatric unit, Kyoto University Hospital, Sakyo-ku, Kyoto, Japan
- * E-mail: (HK); (MY)
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James MO, Ambadapadi S. Interactions of cytosolic sulfotransferases with xenobiotics. Drug Metab Rev 2014; 45:401-14. [PMID: 24188364 DOI: 10.3109/03602532.2013.835613] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cytosolic sulfotransferases are a superfamily of enzymes that catalyze the transfer of the sulfonic group from 3'-phosphoadenosine-5'-phosphosulfate to hydroxy or amine groups in substrate molecules. The human cytosolic sulfotransferases that have been most studied, namely SULT1A1, SULT1A3, SULT1B1, SULT1E1 and SULT2A1, are expressed in different tissues of the body, including liver, intestine, adrenal, brain and skin. These sulfotransferases play important roles in the sulfonation of endogenous molecules such as steroid hormones and neurotransmitters, and in the elimination of xenobiotic molecules such as drugs, environmental chemicals and natural products. There is often overlapping substrate selectivity among the sulfotransferases, although one isoform may exhibit greater enzyme efficiency than other isoforms. Similarly, inhibitors or enhancers of one isoform often affect other isoforms, but typically with different potency. This means that if the activity of one form of sulfotransferase is altered (either inhibited or enhanced) by the presence of a xenobiotic, the sulfonation of endogenous and xenobiotic substrates for other isoforms may well be affected. There are more examples of inhibitors than enhancers of sulfonation. Modulators of sulfotransferase enzymes include natural products ingested as part of the human diet as well as environmental chemicals and drugs. This review will discuss recent work on such interactions.
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Affiliation(s)
- Margaret O James
- Department of Medicinal Chemistry, University of Florida, Gainesville , FL , USA
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Liu SL, Zhang SY, Wang MJ, Jiang H, Yang YX, Chen L. Demethylzeylasteral exhibits dose-dependent inhibitory behaviour towards estradiol glucuronidation. Eur J Drug Metab Pharmacokinet 2014; 39:99-102. [PMID: 23807732 DOI: 10.1007/s13318-013-0147-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 06/15/2013] [Indexed: 02/05/2023]
Abstract
The disturbance of estradiol level might induce the occurence of some diseases, including cancer. Estradiol is mainly metabolized through the conjugation reactions, including the sulfation and glucuronidation reactions. The present study tried to evaluate the inhibition of estradiol glucuronidation by the major ingredients of Tripterygium wilfordii Hook F. demethylzeylasteral. Selective ion monitoring at negative ion mode ([M⁺ H⁻] = 447) was employed to monitor the two glucuronides of estradiol. The reaction rate was determined through comparison of peak area of these two glucuronides. Lineweaver-Burk plot and Dixon plot were utilized to determine the inhibition kinetic type, and the inhibition kinetic parameters (K i) were calculated using the second plot. Competitive inhibition of demethylzeylasteral towards the formation of two glucuronides of estradiol was demonstrated, and the K i values were calculated to be 453.3 and 110.9 μM, respectively. All these results will remind us the risk of elevated serum concentrations of estradiol due to the inhibition of estradiol glucuronidation by demethylzeylasteral.
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Affiliation(s)
- Su-Lin Liu
- Intervention Therapy Department, First Affiliated Hospital of Shantou University Medical College, Shantou, China,
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Brantley SJ, Argikar AA, Lin YS, Nagar S, Paine MF. Herb-drug interactions: challenges and opportunities for improved predictions. Drug Metab Dispos 2014; 42:301-17. [PMID: 24335390 PMCID: PMC3935140 DOI: 10.1124/dmd.113.055236] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/11/2013] [Indexed: 01/23/2023] Open
Abstract
Supported by a usage history that predates written records and the perception that "natural" ensures safety, herbal products have increasingly been incorporated into Western health care. Consumers often self-administer these products concomitantly with conventional medications without informing their health care provider(s). Such herb-drug combinations can produce untoward effects when the herbal product perturbs the activity of drug metabolizing enzymes and/or transporters. Despite increasing recognition of these types of herb-drug interactions, a standard system for interaction prediction and evaluation is nonexistent. Consequently, the mechanisms underlying herb-drug interactions remain an understudied area of pharmacotherapy. Evaluation of herbal product interaction liability is challenging due to variability in herbal product composition, uncertainty of the causative constituents, and often scant knowledge of causative constituent pharmacokinetics. These limitations are confounded further by the varying perspectives concerning herbal product regulation. Systematic evaluation of herbal product drug interaction liability, as is routine for new drugs under development, necessitates identifying individual constituents from herbal products and characterizing the interaction potential of such constituents. Integration of this information into in silico models that estimate the pharmacokinetics of individual constituents should facilitate prospective identification of herb-drug interactions. These concepts are highlighted with the exemplar herbal products milk thistle and resveratrol. Implementation of this methodology should help provide definitive information to both consumers and clinicians about the risk of adding herbal products to conventional pharmacotherapeutic regimens.
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Affiliation(s)
- Scott J Brantley
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina (S.J.B.); Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, Pennsylvania (A.A.A., S.N.); Department of Pharmaceutics, University of Washington, Seattle, Washington (Y.S.L.); and College of Pharmacy, Washington State University, Spokane, Washington (M.F.P.)
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Maier-Salamon A, Böhmdorfer M, Riha J, Thalhammer T, Szekeres T, Jaeger W. Interplay between metabolism and transport of resveratrol. Ann N Y Acad Sci 2013; 1290:98-106. [DOI: 10.1111/nyas.12198] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
| | - Michaela Böhmdorfer
- Department of Clinical Pharmacy and Diagnostics; University of Vienna; Vienna Austria
| | - Juliane Riha
- Department of Clinical Pharmacy and Diagnostics; University of Vienna; Vienna Austria
| | - Theresia Thalhammer
- Department of Pathophysiology and Allergy Research; Center for Pathophysiology; Medical University of Vienna; Vienna Austria
| | - Thomas Szekeres
- Clinical Institute for Medical and Chemical Laboratory Diagnostics; Medical University of Vienna; Vienna Austria
| | - Walter Jaeger
- Department of Clinical Pharmacy and Diagnostics; University of Vienna; Vienna Austria
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Vijayaprakash S, Langeswaran K, Gowtham Kumar S, Revathy R, Balasubramanian MP. Nephro-protective significance of kaempferol on mercuric chloride induced toxicity in Wistar albino rats. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.biomag.2013.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Knag AC, Verhaegen S, Ropstad E, Mayer I, Meier S. Effects of polar oil related hydrocarbons on steroidogenesis in vitro in H295R cells. CHEMOSPHERE 2013; 92:106-115. [PMID: 23561572 DOI: 10.1016/j.chemosphere.2013.02.046] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Revised: 01/24/2013] [Accepted: 02/17/2013] [Indexed: 06/02/2023]
Abstract
Oil pollution from various sources, including exploration, production and transportation, is a growing global concern. Of particular concern is the environmental impact of produced water (PW), the main waste discharge from oil and gas platforms. In this study, we have investigated the potential of polar hydrocarbon pollutants to disrupt or modulate steroidogenesis in vitro, using a human adrenocortical carcinoma cell line, the H295R assay. Effects of two of the major groups of compounds found in the polar fraction of crude oil and PW; alkylphenols (C(2)- and C(3)-AP) and naphthenic acids (NAs), as well as the polar fraction of PW as a whole has been assessed. Endpoints include hormone (cortisol, estradiol, progesterone, testosterone) production at the functional level and key genes for steroidogenesis (17β-HSD1, 17β-HSD4, 3β-HSD2, ACTHR, CYP11A1, CYP11B1, CYP11B2, CYP17, CYP19, CYP21, DAX1, EPHX, HMGR, SF1, STAR) and metabolism (CYP1A) at the molecular level. All compounds induced the production of both estradiol and progesterone in exposed H295R cells, while the C(3)-AP and NAs decreased the production of testosterone. Exposure to C(2)-AP caused an up-regulation of DAX1 and EPHX, while exposure to NAs caused an up-regulation of ACTHR. All compounds caused an up-regulation of CYP1A1. The results indicated that these hydrocarbon pollutants, including PW, have the potential to disrupt the vitally important process of steroidogenesis.
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Affiliation(s)
- Anne Christine Knag
- Department of Biology, University of Bergen, P.O. Box 7803, N-5020 Bergen, Norway.
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Kulanthaivel L, Srinivasan P, Shanmugam V, Periyasamy BM. Therapeutic efficacy of kaempferol against AFB1 induced experimental hepatocarcinogenesis with reference to lipid peroxidation, antioxidants and biotransformation enzymes. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.bionut.2012.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Macpherson L, Matthews J. Inhibition of aryl hydrocarbon receptor-dependent transcription by resveratrol or kaempferol is independent of estrogen receptor α expression in human breast cancer cells. Cancer Lett 2010; 299:119-29. [PMID: 20846786 DOI: 10.1016/j.canlet.2010.08.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 08/11/2010] [Accepted: 08/13/2010] [Indexed: 02/07/2023]
Abstract
Resveratrol and kaempferol are natural chemopreventative agents that are also aryl hydrocarbon receptor (AHR) antagonists and estrogen receptor (ER) agonists. In this study we evaluated the role of ERα in resveratrol- and kaempferol-mediated inhibition of AHR-dependent transcription. Kaempferol or resveratrol inhibited dioxin-induced cytochrome P450 1A1 (CYP1A1) and CYP1B1 expression levels and recruitment of AHR, ERα and co-activators to CYP1A1 and CYP1B1. Both phytochemicals induced the expression and recruitment of ERα to gene amplified in breast cancer 1 (GREB1). RNAi-mediated knockdown of ERα in T-47D cells did not affect the inhibitory action of either phytochemical on AHR activity. Both compounds also inhibited AHR-dependent transcription in ERα-negative MDA-MB-231 and BT-549 breast cancer cells. These data show that ERα does not contribute to the AHR-inhibitory activities of resveratrol and kaempferol.
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Affiliation(s)
- Laura Macpherson
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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Higley EB, Newsted JL, Zhang X, Giesy JP, Hecker M. Assessment of chemical effects on aromatase activity using the H295R cell line. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2010; 17:1137-48. [PMID: 20087668 DOI: 10.1007/s11356-009-0285-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 12/17/2009] [Indexed: 05/25/2023]
Abstract
BACKGROUND, AIM, AND SCOPE In response to concerns about chemical substances that can alter the function of endocrine systems and may result in adverse effects on human and ecosystem health, a number of in vitro tests have been developed to identify and assess the endocrine disrupting potential of chemicals and environmental samples. One endpoint that is frequently used in in vitro models for the assessment of chemical effects on the endocrine system is the alteration of aromatase activity (AA). Aromatase is the enzyme responsible for converting androgens to estrogens. Some commonly used aromatase assays, including the human microsomal assay that is a mandatory test in US-EPA's endocrine disruptor screening program (EDSP), detect only direct effects of chemicals on aromatase activity and not indirect effects, including changes in gene expression or transcription factors. This can be a problem for chemical screening initiatives such as the EDSP because chemicals can affect aromatase both indirectly and directly. Here we compare direct, indirect, and combined measurements of AA using the H295R cell line after exposure to seven model chemicals. Furthermore, we compare the predictability of the different types of AA measurements for 17beta-estradiol (E2) and testosterone (T) production in vitro. MATERIALS AND METHODS H295R cells were exposed to forskolin, atrazine, letrozole, prochloraz, ketoconazole, aminoglutethimide, and prometon for 48 h. Direct, indirect, and combined effects on aromatase activity were measured using a tritiated water-release assay. Direct effects on aromatase activity were assessed by exposing cells only during the conduct of the tritium-release assay. Indirect effects were measured after exposing cells for 48 h to test chemicals, and then measuring AA without further chemical addition. Combined AA was measured by exposing cells prior and during the conduction of the tritium-release assay. Estradiol and testosterone were measured by ELISA. RESULTS AND DISCUSSION Exposure to the aromatase inhibitors letrozole, prochloraz, ketoconazole, and aminoglutethimide resulted in greater indirect aromatase activity after a 48-h exposure due to presumed compensatory mechanisms involved in aromatase activity regulation. Forskolin and atrazine caused similar changes in hormone production and enzyme profiles, and both chemicals resulted in a dose-dependent increase in E2, T, and indirect AA. Neither of these two chemicals directly affected AA. For most of the chemicals, direct and combined AA and E2 were good predictors of the mechanism of action of the chemical, with regard to AA. Indirect aromatase activity was a less precise predictor of effects at the hormone level because of presumed feedback loops that made it difficult to predict the chemicals' true effects, mostly seen with the aromatase inhibitors. Further, it was found that direct and indirect AA measurements were not reliable predictors of effects on E2 for general inducers and inhibitors, respectively. CONCLUSIONS Differential modulation of AA and hormone production was observed in H295R cells after exposure to seven model chemicals, illustrating the importance of measuring multiple endpoints when describing mechanisms of action in vitro. RECOMMENDATIONS AND PERSPECTIVES For future work with the H295R, it is recommended that a combination of direct and indirect aromatase measurements is used because it was best in predicting the effects of a chemical on E2 production and its mechanism of action. Further, it was shown that direct AA measurements, which are a common way to measure AA, must be used with caution in vitro.
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Affiliation(s)
- Eric B Higley
- Toxicology Centre and Department Veterinary Biomedical Sciences, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK, Canada.
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