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Han SJ, Zhang Y, Kim I, Chay KO, Yoon HJ, Jang DI, Yang SY, Park J, Woo HA, Park I, Lee SR. Redox regulation of the tumor suppressor PTEN by the thioredoxin system and cumene hydroperoxide. Free Radic Biol Med 2017; 112:277-286. [PMID: 28774816 DOI: 10.1016/j.freeradbiomed.2017.07.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 07/06/2017] [Accepted: 07/29/2017] [Indexed: 12/22/2022]
Abstract
Intracellular redox status influences the oxidation and enzyme activity of the tumor suppressor phosphatase and tensin homolog on chromosome 10 (PTEN). Cumene hydroperoxide (CuHP), an organic hydroperoxide, is a known tumor promoter. However, molecular targets and action mechanism of CuHP in tumor promotion have not been well characterized. In this study, we investigated the effect of CuHP on the redox state of PTEN in HeLa cells. In addition, the intracellular reducing system of oxidized PTEN was analyzed using a biochemical approach and the effect of CuHP on this reducing system was also analyzed. While PTEN oxidized by hydrogen peroxide is progressively converted to its reduced form, PTEN was irreversibly oxidized by exposure to CuHP in HeLa cells. A combination of protein fractionation and mass analysis showed that the reducing system of PTEN was comprised of NADPH, thioredoxin reductase (TrxR), and thioredoxin (Trx). Although CuHP-mediated PTEN oxidation was not reversible in cells, CuHP-oxidized PTEN was reactivated by the exogenous Trx system, indicating that the cellular Trx redox system for PTEN is inactivated by CuHP. We present evidence that PTEN oxidation and the concomitant inhibition of thioredoxin by CuHP results in irreversible oxidation of PTEN in HeLa cells. In addition, ablation of peroxiredoxin (Prdx) enhanced CuHP-induced PTEN oxidation in cells. These results provide a new line of evidence that PTEN might be a crucial determinant of cell fate in response to cellular oxidative stress induced by organic hydroperoxides.
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Affiliation(s)
- Seong-Jeong Han
- Department of Biochemistry, Department of Biomedical Sciences, Research Center for Aging and Geriatrics, Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju 501-190, Republic of Korea; COTDE Inc., 19-3, Ugakgol-gil, Susin-myeon, Cheonan-si, Chungcheongnam-do 330-882, Republic of Korea
| | - Ying Zhang
- Department of Biochemistry, Department of Biomedical Sciences, Research Center for Aging and Geriatrics, Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju 501-190, Republic of Korea
| | - Inyoung Kim
- Department of Biochemistry, Department of Biomedical Sciences, Research Center for Aging and Geriatrics, Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju 501-190, Republic of Korea
| | - Kee-Oh Chay
- Department of Biochemistry, Department of Biomedical Sciences, Research Center for Aging and Geriatrics, Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju 501-190, Republic of Korea
| | - Hyun Joong Yoon
- Department of Biochemistry, Department of Biomedical Sciences, Research Center for Aging and Geriatrics, Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju 501-190, Republic of Korea
| | - Dong Il Jang
- COTDE Inc., 19-3, Ugakgol-gil, Susin-myeon, Cheonan-si, Chungcheongnam-do 330-882, Republic of Korea
| | - Sung Yeul Yang
- Department of Biochemistry, Department of Biomedical Sciences, Research Center for Aging and Geriatrics, Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju 501-190, Republic of Korea
| | - Jiyoung Park
- College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750, Republic of Korea
| | - Hyun Ae Woo
- College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750, Republic of Korea
| | - Iha Park
- Department of Biochemistry, Department of Biomedical Sciences, Research Center for Aging and Geriatrics, Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju 501-190, Republic of Korea.
| | - Seung-Rock Lee
- Department of Biochemistry, Department of Biomedical Sciences, Research Center for Aging and Geriatrics, Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju 501-190, Republic of Korea.
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Kasai H. What causes human cancer? Approaches from the chemistry of DNA damage. Genes Environ 2016; 38:19. [PMID: 27375797 PMCID: PMC4929788 DOI: 10.1186/s41021-016-0046-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/11/2016] [Indexed: 11/23/2022] Open
Abstract
To prevent human cancers, environmental mutagens must be identified. A common mechanism of carcinogenesis is DNA damage, and thus it is quite possible that environmental mutagens can be trapped as adducts by DNA components. It is also important to identify new types of DNA damaging reactions and clarify their mechanisms. In this paper, I will provide typical examples of our efforts to identify DNA damage by environmental agents, from chemistry-based studies. 1) Oxidative DNA damage: 8-Hydroxydeoxyguanosine (8-OHdG, 8-oxodG) was discovered during a structural study of DNA modifications caused in vitro by heating glucose, which was used as a model of cooked foods. We found that various oxygen radical-forming agents induced the formation of 8-OHdG in DNA, in vitro and in vivo. Analyses of the urinary 8-OHdG levels are useful to assess the extent of oxidative DNA damage in a human population. 2) Lipid peroxide-derived DNA adducts: We searched for mutagens that react with deoxynucleosides, in model systems of lipid peroxidation. The reaction mixtures were analyzed by high performance liquid chromatography (HPLC), and we discovered various lipid peroxide-derived mutagens, including new mutagens. Some of these adducts were detected in human DNA. These mutagens may be involved in lipid peroxide-related cancers. 3) Methylation of cytosine by free radicals: Methylation of the cytosine C-5 position is an important mechanism of carcinogenesis, in addition to gene mutations. However, the actual mechanisms of de novo methylation in relation to environmental agents are not clear. We found that cytosine C-5 methylation occurred by a free radical mechanism. The possible role of this radical-induced DNA methylation in carcinogenesis will be discussed, in relation to the presently accepted concept of cancer epigenetics. In these studies, chemical analyses of the adducts formed in model reactions led to the discoveries of new mutagens and important types of DNA modifications, which seem to be involved in human carcinogenesis.
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Affiliation(s)
- Hiroshi Kasai
- Department of Environmental Oncology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, 1-1, Iseigaoka, Kitakyushu, Yahatanishi-ku 807-8555 Japan
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3
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Rider CV, Chan P, Herbert RA, Kissling GE, Fomby LM, Hejtmancik MR, Witt KL, Waidyanatha S, Travlos GS, Kadiiska MB. Dermal Exposure to Cumene Hydroperoxide: Assessing Its Toxic Relevance and Oxidant Potential. Toxicol Pathol 2016; 44:749-62. [PMID: 26985019 DOI: 10.1177/0192623316636712] [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] [Indexed: 12/31/2022]
Abstract
Cumene hydroperoxide (CHP) is a high production volume chemical that is used to generate phenol and acetone. Dermal exposure to CHP was hypothesized to result in systemic tissue toxicity, production of free radicals, and consequent decrease in plasma antioxidant levels. To evaluate the hypothesis and characterize the toxicity of CHP, male and female B6C3F1/N mice and F344/N rats were exposed to varying doses of CHP applied topically for 14 or 90 days. No significant changes in survival or body weight of mice and rats were observed following 14 days of exposure. However, 90 days of CHP exposure at the high dose (12 mg/kg) triggered a significant decrease (-15%) in the body weight of the male rat group only. Irritation of the skin was observed at the site of application and was characterized by inflammation and epidermal hyperplasia. In treated animals, histology of liver tissue, free radical generation, and antioxidant levels in blood plasma were not significantly changed as compared to the corresponding controls. Consistent with the lack of systemic damage, no increase in micronucleated erythrocytes was seen in peripheral blood. In conclusion, topical CHP application caused skin damage only at the application site and did not cause systemic tissue impairment.
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Affiliation(s)
- Cynthia V Rider
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
| | - Po Chan
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
| | - Ron A Herbert
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
| | - Grace E Kissling
- Division of Intramural Research, Biostatistics & Computational Biology Branch, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
| | | | | | - Kristine L Witt
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
| | - Suramya Waidyanatha
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
| | - Greg S Travlos
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
| | - Maria B Kadiiska
- Division of Intramural Research, Inflammation, Immunity, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
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Potnis PA, Mitkus R, Elnabawi A, Squibb K, Powell JL. Role of NF-κB in the oxidative stress-induced lung inflammatory response to iron and selenium at ambient levels. Toxicol Res (Camb) 2013. [DOI: 10.1039/c3tx50012h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Gong Z, Shi Y, Zhu Z, Li X, Ye Y, Zhang J, Li A, Li G, Zhou J. JWA deficiency suppresses dimethylbenz[a]anthracene-phorbol ester induced skin papillomas via inactivation of MAPK pathway in mice. PLoS One 2012; 7:e34154. [PMID: 22461904 PMCID: PMC3312911 DOI: 10.1371/journal.pone.0034154] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 02/23/2012] [Indexed: 12/17/2022] Open
Abstract
Our previous studies indicated that JWA plays an important role in DNA damage repair, cell migration, and regulation of MAPKs. In this study, we investigated the role of JWA in chemical carcinogenesis using conditional JWA knockout (JWAΔ2/Δ2) mice and two-stage model of skin carcinogenesis. Our results indicated that JWAΔ2/Δ2 mice were resistant to the development of skin papillomas initiated by 7, 12-dimethylbenz(a)anthracene (DMBA) followed by promotion with 12-O-tetradecanoylphorbol-13-acetate (TPA). In JWAΔ2/Δ2 mice, the induction of papilloma was delayed, and the tumor number and size were reduced. In primary keratinocytes from JWAΔ2/Δ2 mice, DMBA exposure induced more intensive DNA damage, while TPA-promoted cell proliferation was reduced. The further mechanistic studies showed that JWA deficiency blocked TPA-induced activation of MAPKs and its downstream transcription factor Elk1 both in vitro and in vivo. JWAΔ2/Δ2 mice are resistance to tumorigenesis induced by DMBA/TPA probably through inhibition of transcription factor Elk1 via MAPKs. These results highlight the importance of JWA in skin homeostasis and in the process of skin tumor development.
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Affiliation(s)
- Zhenghua Gong
- Department of Molecular Cell Biology & Toxicology, the Key Laboratory of Modern Toxicology, Ministry of Education and Department of Occupational Medicine and Environmental Health, School of Public Health; Nanjing Medical University, Nanjing, People's Republic of China
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; Nanjing Medical University, Nanjing, People's Republic of China
| | - Yaowei Shi
- Department of Molecular Cell Biology & Toxicology, the Key Laboratory of Modern Toxicology, Ministry of Education and Department of Occupational Medicine and Environmental Health, School of Public Health; Nanjing Medical University, Nanjing, People's Republic of China
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; Nanjing Medical University, Nanjing, People's Republic of China
| | - Ze Zhu
- Department of Molecular Cell Biology & Toxicology, the Key Laboratory of Modern Toxicology, Ministry of Education and Department of Occupational Medicine and Environmental Health, School of Public Health; Nanjing Medical University, Nanjing, People's Republic of China
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; Nanjing Medical University, Nanjing, People's Republic of China
| | - Xuan Li
- Department of Molecular Cell Biology & Toxicology, the Key Laboratory of Modern Toxicology, Ministry of Education and Department of Occupational Medicine and Environmental Health, School of Public Health; Nanjing Medical University, Nanjing, People's Republic of China
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; Nanjing Medical University, Nanjing, People's Republic of China
| | - Yang Ye
- Department of Molecular Cell Biology & Toxicology, the Key Laboratory of Modern Toxicology, Ministry of Education and Department of Occupational Medicine and Environmental Health, School of Public Health; Nanjing Medical University, Nanjing, People's Republic of China
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; Nanjing Medical University, Nanjing, People's Republic of China
| | - Jianbing Zhang
- Department of Molecular Cell Biology & Toxicology, the Key Laboratory of Modern Toxicology, Ministry of Education and Department of Occupational Medicine and Environmental Health, School of Public Health; Nanjing Medical University, Nanjing, People's Republic of China
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; Nanjing Medical University, Nanjing, People's Republic of China
| | - Aiping Li
- Department of Molecular Cell Biology & Toxicology, the Key Laboratory of Modern Toxicology, Ministry of Education and Department of Occupational Medicine and Environmental Health, School of Public Health; Nanjing Medical University, Nanjing, People's Republic of China
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; Nanjing Medical University, Nanjing, People's Republic of China
| | - Gang Li
- Department of Dermatology and Skin Science, Jack Bell Research Centre, Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jianwei Zhou
- Department of Molecular Cell Biology & Toxicology, the Key Laboratory of Modern Toxicology, Ministry of Education and Department of Occupational Medicine and Environmental Health, School of Public Health; Nanjing Medical University, Nanjing, People's Republic of China
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; Nanjing Medical University, Nanjing, People's Republic of China
- * E-mail:
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Johansson SGH, Emilsson K, Grøtli M, Börje A. Structural influence on radical formation and sensitizing capacity of alkylic limonene hydroperoxide analogues in allergic contact dermatitis. Chem Res Toxicol 2010; 23:677-88. [PMID: 20163165 DOI: 10.1021/tx900433n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydroperoxides are known to be strong contact allergens and a common cause of contact allergy. They are easily formed by the autoxidation of, for example, fragrance terpenes, compounds that are common in perfumes, cosmetics, and household products. A requirement of the immunological mechanisms of contact allergy is the formation of an immunogenic hapten-protein complex. For hydroperoxides, a radical mechanism is postulated for this formation. In our previous investigations of allylic limonene hydroperoxides, we found that the formation of carbon- and oxygen-centered radicals, as well as the sensitizing capacity, is influenced by the structure of the hydroperoxides. The aim of the present work was to further investigate the connection between structure, radical formation, and sensitizing capacity by studying alkylic analogues of the previously investigated allylic limonene hydroperoxides. The radical formation was studied in radical-trapping experiments employing 5,10,15,20-tetraphenyl-21H,23H-porphine iron(III) chloride as an initiator and 1,1,3,3-tetramethylisoindolin-2-yloxyl as a radical trapper. We found that the investigated hydroperoxides initially form carbon- and oxygen-centered radicals that subsequently form alcohols and ketones. Trapped carbon-centered radicals and nonradical products were isolated and identified. Small changes in structure, like the omission of the endocyclic double bond or the addition of a methyl group, resulted in large differences in radical formation. The results indicate that alkoxyl radicals seem to be more important than carbon-centered radicals in the immunogenic complex formation. The sensitizing capacities were studied in the murine local lymph node assay (LLNA), and all hydroperoxides tested were found to be potent sensitizers. For two of the hydroperoxides investigated, the recently suggested thiol-ene reaction is a possible mechanism for the formation of immunogenic complexes. For the third investigated, fully saturated, hydroperoxide, the thiol-ene mechanism is not possible for immunogenic complex formation. This strongly indicates that several radical reaction pathways for immunogenic complex formation of limonene hydroperoxides are active in parallel.
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Affiliation(s)
- Staffan G H Johansson
- Dermatochemistry and Skin Allergy and Medicinal Chemistry, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden
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7
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Johansson S, Redeby T, Altamore TM, Nilsson U, Börje A. Mechanistic proposal for the formation of specific immunogenic complexes via a radical pathway: a key step in allergic contact dermatitis to olefinic hydroperoxides. Chem Res Toxicol 2010; 22:1774-81. [PMID: 19725554 DOI: 10.1021/tx9001435] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The widespread use of scented products causes an increase of allergic contact dermatitis to fragrance compounds in Western countries today. Many fragrance compounds are prone to autoxidation, forming hydroperoxides as their primary oxidation products. Hydroperoxides are known to be strong allergens and to form specific immunogenic complexes. However, the mechanisms for the formation of the immunogenic complexes are largely unknown. We have investigated this mechanism for (5R)-5-isopropenyl-2-methyl-2-cyclohexene-1-hydroperoxide (Lim-2-OOH) by studying the formation of adducts in the reaction between this hydroperoxide and 5,10,15,20-tetraphenyl-21H,23H-porphine iron(III) chloride (Fe(III)TPPCl) in the presence of protected cysteine (NAc-Cys-OMe) or glutathione (GSH). Isolated adducts originate from the addition of the thiol group of NAc-Cys-OMe over the carbon-carbon double bonds of carvone. Furthermore, adducts between NAc-Cys-OMe and carveol as well as between GSH and carvone have been identified. The formation of these adducts most likely proceeds via the radical thiol-ene mechanism. The addition of a terpene moiety to cysteine offers an explanation of the specificity of the immune response to structurally different hydroperoxides. These results also explain the lack of cross-reactivity between carvone and Lim-2-OOH. In conclusion, we propose that immunogenic complexes of olefinic hydroperoxides can be formed via the radical thiol-ene mechanism. These complexes will be specific for the individual olefinic hydroperoxides due to the inclusion of a terpene moiety derived from the hydroperoxide.
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Affiliation(s)
- Staffan Johansson
- Department of Chemistry, Dermatochemistry and Skin Allergy, University of Gothenburg, Gothenburg, Sweden
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8
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Redeby T, Nilsson U, Altamore TM, Ilag L, Ambrosi A, Broo K, Börje A, Karlberg AT. Specific Adducts Formed through a Radical Reaction between Peptides and Contact Allergenic Hydroperoxides. Chem Res Toxicol 2009; 23:203-10. [DOI: 10.1021/tx9003352] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Theres Redeby
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Ulrika Nilsson
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Timothy M. Altamore
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Leopold Ilag
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Annalisa Ambrosi
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Kerstin Broo
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Anna Börje
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Ann-Therese Karlberg
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
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9
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Kasai H, Kawai K. DNA methylation at the C-5 position of cytosine by methyl radicals: a possible role for epigenetic change during carcinogenesis by environmental agents. Chem Res Toxicol 2009; 22:984-9. [PMID: 19522545 DOI: 10.1021/tx900099s] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
During carcinogenesis, methylation of the C-5 position of cytosines in the promoter region of tumor suppressor genes is often observed. Enzymatic DNA methylation is a widely accepted mechanism for this phenomenon. It is interesting to propose a free radical mechanism for 5-methyldeoxycytidine (m(5)dC) production, because the C-5 position of cytosine is an active site for free radical reactions. When deoxycytidine (dC) and cumene hydroperoxide (CuOOH), a tumor promoter and a methyl radical producer, were reacted in the presence of ferrous ion at pH 7.4, the formation of m(5)dC was observed. The same reaction also proceeded with t-butyl hydroperoxide (BuOOH). The formation of m(5)dC was also observed in DNA by the CuOOH treatment. This is the first report of chemical DNA methylation at cytosine C-5 by environmental tumor promoters. We propose here that this reaction is one of the important mechanisms of de novo DNA methylation during carcinogenesis, because methyl radicals are produced by the biotransformation of various endogenous and exogenous compounds.
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Affiliation(s)
- Hiroshi Kasai
- Department of Environmental Oncology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan.
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10
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Ding M, Kisin ER, Zhao J, Bowman L, Lu Y, Jiang B, Leonard S, Vallyathan V, Castranova V, Murray AR, Fadeel B, Shvedova AA. Size-dependent effects of tungsten carbide-cobalt particles on oxygen radical production and activation of cell signaling pathways in murine epidermal cells. Toxicol Appl Pharmacol 2009; 241:260-8. [PMID: 19747498 DOI: 10.1016/j.taap.2009.09.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 09/03/2009] [Accepted: 09/03/2009] [Indexed: 01/14/2023]
Abstract
Hard metal or cemented carbide consists of a mixture of tungsten carbide (WC) (85%) and metallic cobalt (Co) (5-15%). WC-Co is considered to be potentially carcinogenic to humans. However, no comparison of the adverse effects of nano-sized WC-Co particles is available to date. In the present study, we compared the ability of nano- and fine-sized WC-Co particles to form free radicals and propensity to activate the transcription factors, AP-1 and NF-kappaB, along with stimulation of mitogen-activated protein kinase (MAPK) signaling pathways in a mouse epidermal cell line (JB6 P(+)). Our results demonstrated that nano-WC-Co generated a higher level of hydroxyl radicals, induced greater oxidative stress, as evidenced by a decrease of GSH levels, and caused faster JB6 P(+) cell growth/proliferation than observed after exposure of cells to fine WC-Co. In addition, nano-WC-Co activated AP-1 and NF-kappaB more efficiently in JB6(+/+) cells as compared to fine WC-Co. Experiments using AP-1-luciferase reporter transgenic mice confirmed the activation of AP-1 by nano-WC-Co. Nano- and fine-sized WC-Co particles also stimulated MAPKs, including ERKs, p38, and JNKs with significantly higher potency of nano-WC-Co. Finally, co-incubation of the JB6(+/+) cells with N-acetyl-cysteine decreased AP-1 activation and phosphorylation of ERKs, p38 kinase, and JNKs, thus suggesting that oxidative stress is involved in WC-Co-induced toxicity and AP-1 activation.
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Affiliation(s)
- M Ding
- Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA
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11
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Kaur G, Alam MS, Athar M. Cumene hydroperoxide debilitates macrophage physiology by inducing oxidative stress: Possible protection by α-tocopherol. Chem Biol Interact 2009; 179:94-102. [DOI: 10.1016/j.cbi.2008.12.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2008] [Revised: 12/08/2008] [Accepted: 12/09/2008] [Indexed: 12/20/2022]
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12
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Oxidative stress and inflammatory response in dermal toxicity of single-walled carbon nanotubes. Toxicology 2009; 257:161-71. [DOI: 10.1016/j.tox.2008.12.023] [Citation(s) in RCA: 265] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Revised: 12/16/2008] [Accepted: 12/18/2008] [Indexed: 11/20/2022]
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