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Tsuji JS, Chang ET, Gentry PR, Clewell HJ, Boffetta P, Cohen SM. Dose-response for assessing the cancer risk of inorganic arsenic in drinking water: the scientific basis for use of a threshold approach. Crit Rev Toxicol 2019; 49:36-84. [DOI: 10.1080/10408444.2019.1573804] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | - Ellen T. Chang
- Exponent, Inc., Menlo Park, CA and Stanford Cancer Institute, Stanford, CA, USA
| | | | | | - Paolo Boffetta
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Samuel M. Cohen
- Havlik-Wall Professor of Oncology, Department of Pathology and Microbiology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
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2
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Holcomb N, Goswami M, Han SG, Scott T, D'Orazio J, Orren DK, Gairola CG, Mellon I. Inorganic arsenic inhibits the nucleotide excision repair pathway and reduces the expression of XPC. DNA Repair (Amst) 2017; 52:70-80. [PMID: 28237621 DOI: 10.1016/j.dnarep.2017.02.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 01/11/2017] [Accepted: 02/12/2017] [Indexed: 11/17/2022]
Abstract
Chronic exposure to arsenic, most often through contaminated drinking water, has been linked to several types of cancer in humans, including skin and lung cancer. However, the mechanisms underlying its role in causing cancer are not well understood. There is evidence that exposure to arsenic can enhance the carcinogenicity of UV light in inducing skin cancers and may enhance the carcinogenicity of tobacco smoke in inducing lung cancers. The nucleotide excision repair (NER) pathway removes different types of DNA damage including those produced by UV light and components of tobacco smoke. The aim of the present study was to investigate the effect of sodium arsenite on the NER pathway in human lung fibroblasts (IMR-90 cells) and primary mouse keratinocytes. To measure NER, we employed a slot-blot assay to quantify the introduction and removal of UV light-induced 6-4 photoproducts (6-4 PP) and cyclobutane pyrimidine dimers (CPDs). We find a concentration-dependent inhibition of the removal of 6-4 PPs and CPDs in both cell types treated with arsenite. Treatment of both cell types with arsenite resulted in a significant reduction in the abundance of XPC, a protein that is critical for DNA damage recognition in NER. The abundance of RNA expressed from several key NER genes was also significantly reduced by treatment of IMR-90 cells with arsenite. Finally, treatment of IMR-90 cells with MG-132 abrogated the reduction in XPC protein, suggesting an involvement of the proteasome in the reduction of XPC protein produced by treatment of cells with arsenic. The inhibition of NER by arsenic may reflect one mechanism underlying the role of arsenic exposure in enhancing cigarette smoke-induced lung carcinogenesis and UV light-induced skin cancer, and it may provide some insights into the emergence of arsenic trioxide as a chemotherapeutic agent.
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Affiliation(s)
- Nathaniel Holcomb
- Department of Toxicology and Cancer Biology, The Markey Cancer Center, University of Kentucky, Lexington, KY, United States
| | - Mamta Goswami
- Department of Toxicology and Cancer Biology, The Markey Cancer Center, University of Kentucky, Lexington, KY, United States
| | - Sung Gu Han
- Toxicology Laboratory, Department of Food Science and Biotechnology of Animal Resources, College of Animal Bioscience and Technology, Konkuk University, Seoul 05029, Republic of Korea
| | - Tim Scott
- Department of Toxicology and Cancer Biology, The Markey Cancer Center, University of Kentucky, Lexington, KY, United States
| | - John D'Orazio
- Department of Toxicology and Cancer Biology, The Markey Cancer Center, University of Kentucky, Lexington, KY, United States
| | - David K Orren
- Department of Toxicology and Cancer Biology, The Markey Cancer Center, University of Kentucky, Lexington, KY, United States
| | - C Gary Gairola
- Department of Toxicology and Cancer Biology, The Markey Cancer Center, University of Kentucky, Lexington, KY, United States
| | - Isabel Mellon
- Department of Toxicology and Cancer Biology, The Markey Cancer Center, University of Kentucky, Lexington, KY, United States.
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3
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Hunt KM, Srivastava RK, Elmets CA, Athar M. The mechanistic basis of arsenicosis: pathogenesis of skin cancer. Cancer Lett 2014; 354:211-9. [PMID: 25173797 PMCID: PMC4193806 DOI: 10.1016/j.canlet.2014.08.016] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 08/12/2014] [Accepted: 08/12/2014] [Indexed: 12/25/2022]
Abstract
Significant amounts of arsenic have been found in the groundwater of many countries including Argentina, Bangladesh, Chile, China, India, Mexico, and the United States with an estimated 200 million people at risk of toxic exposure. Although chronic arsenic poisoning damages many organ systems, it usually first presents in the skin with manifestations including hyperpigmentation, hyperkeratoses, Bowen's disease, squamous cell carcinoma, and basal cell carcinoma. Arsenic promotes oxidative stress by upregulating nicotinamide adenine dinucleotide phosphate oxidase, uncoupling nitric oxide synthase, and by depleting natural antioxidants such as nitric oxide and glutathione in addition to targeting other proteins responsible for the maintenance of redox homeostasis. It causes immune dysfunction and tissue inflammatory responses, which may involve activation of the unfolded protein response signaling pathway. In addition, the dysregulation of other molecular targets such as nuclear factor kappa B, Hippo signaling protein Yap, and the mineral dust-induced proto-oncogene may orchestrate the pathogenesis of arsenic-mediated health effects. The metalloid decreases expression of tumor suppressor molecules and increases expression of pro-inflammatory mitogen-activated protein kinase pathways leading to a tumor-promoting tissue microenvironment. Cooperation of upregulated signal transduction molecules with DNA damage may abrogate apoptosis, promote proliferation, and enhance cell survival. Genomic instability via direct DNA damage and weakening of several cellular DNA repair mechanisms could also be important cancer development mechanisms in arsenic-exposed populations. Thus, arsenic mediates its toxicity by generating oxidative stress, causing immune dysfunction, promoting genotoxicity, hampering DNA repair, and disrupting signal transduction, which may explain the complex disease manifestations seen in arsenicosis.
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Affiliation(s)
- Katherine M Hunt
- University of Alabama at Birmingham, University of Alabama School of Medicine, 1670 University Blvd., Birmingham, Alabama 35233, USA
| | - Ritesh K Srivastava
- Department of Dermatology and Skin Disease Research Center, University of Alabama at Birmingham, VH 509, 1530 3rd Ave. S., Birmingham, Alabama 35294, USA
| | - Craig A Elmets
- Department of Dermatology and Skin Disease Research Center, University of Alabama at Birmingham, VH 509, 1530 3rd Ave. S., Birmingham, Alabama 35294, USA
| | - Mohammad Athar
- Department of Dermatology and Skin Disease Research Center, University of Alabama at Birmingham, VH 509, 1530 3rd Ave. S., Birmingham, Alabama 35294, USA.
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Jomova K, Jenisova Z, Feszterova M, Baros S, Liska J, Hudecova D, Rhodes CJ, Valko M. Arsenic: toxicity, oxidative stress and human disease. J Appl Toxicol 2011; 31:95-107. [PMID: 21321970 DOI: 10.1002/jat.1649] [Citation(s) in RCA: 347] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 12/06/2010] [Accepted: 12/07/2010] [Indexed: 12/17/2022]
Abstract
Arsenic (As) is a toxic metalloid element that is present in air, water and soil. Inorganic arsenic tends to be more toxic than organic arsenic. Examples of methylated organic arsenicals include monomethylarsonic acid [MMA(V)] and dimethylarsinic acid [DMA(V)]. Reactive oxygen species (ROS)-mediated oxidative damage is a common denominator in arsenic pathogenesis. In addition, arsenic induces morphological changes in the integrity of mitochondria. Cascade mechanisms of free radical formation derived from the superoxide radical, combined with glutathione-depleting agents, increase the sensitivity of cells to arsenic toxicity. When both humans and animals are exposed to arsenic, they experience an increased formation of ROS/RNS, including peroxyl radicals (ROO•), the superoxide radical, singlet oxygen, hydroxyl radical (OH•) via the Fenton reaction, hydrogen peroxide, the dimethylarsenic radical, the dimethylarsenic peroxyl radical and/or oxidant-induced DNA damage. Arsenic induces the formation of oxidized lipids which in turn generate several bioactive molecules (ROS, peroxides and isoprostanes), of which aldehydes [malondialdehyde (MDA) and 4-hydroxy-nonenal (HNE)] are the major end products. This review discusses aspects of chronic and acute exposures of arsenic in the etiology of cancer, cardiovascular disease (hypertension and atherosclerosis), neurological disorders, gastrointestinal disturbances, liver disease and renal disease, reproductive health effects, dermal changes and other health disorders. The role of antioxidant defence systems against arsenic toxicity is also discussed. Consideration is given to the role of vitamin C (ascorbic acid), vitamin E (α-tocopherol), curcumin, glutathione and antioxidant enzymes such as superoxide dismutase, catalase and glutathione peroxidase in their protective roles against arsenic-induced oxidative stress.
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Affiliation(s)
- K Jomova
- Department of Chemistry, Faculty of Natural Sciences, Constantine The Philosopher University, Nitra, Slovakia
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5
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Tokar EJ, Benbrahim-Tallaa L, Ward JM, Lunn R, Sams RL, Waalkes MP. Cancer in experimental animals exposed to arsenic and arsenic compounds. Crit Rev Toxicol 2010; 40:912-27. [PMID: 20812815 PMCID: PMC3076186 DOI: 10.3109/10408444.2010.506641] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Inorganic arsenic is a ubiquitous environmental contaminant that has long been considered a human carcinogen. Recent studies raise further concern about the metalloid as a major, naturally occurring carcinogen in the environment. However, during this same period it has proven difficult to provide experimental evidence of the carcinogenicity of inorganic arsenic in laboratory animals and, until recently, there was considered to be a lack of clear evidence for carcinogenicity of any arsenical in animals. More recent work with arsenical methylation metabolites and early life exposures to inorganic arsenic has now provided evidence of carcinogenicity in rodents. Given that tens of millions of people worldwide are exposed to potentially unhealthy levels of environmental arsenic, in vivo rodent models of arsenic carcinogenesis are a clear necessity for resolving critical issues, such as mechanisms of action, target tissue specificity, and sensitive subpopulations, and in developing strategies to reduce cancers in exposed human populations. This work reviews the available rodent studies considered relevant to carcinogenic assessment of arsenicals, taking advantage of the most recent review by the International Agency for Research on Cancer (IARC) that has not yet appeared as a full monograph but has been summarized (IARC, 2009 , IARC Special Report: Policy, Vol. 10. Lyon: IARC Press, 453–454). Many valid studies show that arsenic can interact with other carcinogens/agents to enhance oncogenesis, and help elucidate mechanisms, and these too are summarized in this review. Finally, this body of rodent work is discussed in light of its impact on mechanisms and in the context of the persistent argument that arsenic is not carcinogenic in animals.
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Affiliation(s)
- Erik J. Tokar
- National Toxicology Program, National Institute of Environmental Health Sciences and Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, Research Triangle Park, NC
| | | | - Jerold M. Ward
- Global VetPathology, 10513 Wayridge Drive, Montgomery Village, MD
| | - Ruth Lunn
- Report on Carcinogens Office, National Toxicology Program, National Institute of Environmental Health Science, Research Triangle Park, NC
| | - Reeder L. Sams
- National Center for Environmental Assessment, Office of Research and Development, US EPA, Research Triangle Park, NC
| | - Michael P. Waalkes
- National Toxicology Program, National Institute of Environmental Health Sciences and Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, Research Triangle Park, NC
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Mitamura T, Doi Y, Kawabe M, Lilja H, Motomura M, Oishi Y, Yoshizawa K, Seki J. Inhibitory potency of tacrolimus ointment on skin tumor induction in a mouse model of an initiation-promotion skin tumor. J Dermatol 2010; 38:562-70. [PMID: 21352294 DOI: 10.1111/j.1346-8138.2010.01046.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tacrolimus is a macrolide immunosuppressive agent, and tacrolimus ointment has been used as therapy for atopic dermatitis worldwide. Given that the immunosuppressive action of tacrolimus raises at least the theoretical potential for an increased risk of skin cancer, accurate assessment of the risk of developing skin cancer by tacrolimus ointment is necessary. The objective of the present study is to investigate the skin tumorigenic potential of commercially available tacrolimus ointment. We conducted a skin carcinogenicity study using an initiation-promotion (I/P) mouse model. Our study consisted of six groups (26 mice/group): sham control, absorptive ointment (AO), macrogol ointment (MO), tacrolimus ointment (TO) vehicle control, TO 0.03%, and TO 0.1%. Following a single administration of 7,12-dimethylbenz[α] anthracene (DMBA) to the dorsal skin of mice as an initiator, 12-O-tetra-decanoylphorbol-13-acetate (TPA) as a promoter and the test drugs were topically administered for 18 weeks. The incidence of skin hyperplasia in the TO 0.03% and TO 0.1% groups was reduced compared with both control groups (P < 0.05). Further, the incidence of skin neoplasia in the TO 0.03% (P < 0.05) and TO 0.1% groups (P < 0.01) was reduced in a dose-dependent manner compared with the sham control group. Tumor promotion effects on skin carcinogenesis were observed in the AO group, whereas inhibitory effects were observed in the MO group. TO 0.03% and TO 0.1% dose-dependently inhibit tumor induction in an I/P mouse model of skin tumors.
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Affiliation(s)
- Takashi Mitamura
- Drug Safety Research Laboratories, Astellas Pharma, Osaka, Japan.
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Delker DA, Geter DR, Roop BC, Ward WO, Ahlborn GJ, Allen JW, Nelson GM, Ouyang M, Welsh W, Chen Y, O'Brien T, Kitchin KT. Oncogene expression profiles in K6/ODC mouse skin and papillomas following a chronic exposure to monomethylarsonous acid. J Biochem Mol Toxicol 2010; 23:406-18. [PMID: 20024957 DOI: 10.1002/jbt.20304] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have previously observed that a chronic drinking water exposure to monomethylarsonous acid [MMA(III)], a cellular metabolite of inorganic arsenic, increases tumor frequency in the skin of keratin VI/ornithine decarboxylase (K6/ODC) transgenic mice. To characterize gene expression profiles predictive of MMA(III) exposure and mode of action of carcinogenesis, skin and papilloma RNA was isolated from K6/ODC mice administered 0, 10, 50, and 100 ppm MMA(III) in their drinking water for 26 weeks. Following RNA processing, the resulting cRNA samples were hybridized to Affymetrix Mouse Genome 430A 2.0 GeneChips(R). Micoarray data were normalized using MAS 5.0 software, and statistically significant genes were determined using a regularized t-test. Significant changes in bZIP transcription factors, MAP kinase signaling, chromatin remodeling, and lipid metabolism gene transcripts were observed following MMA(III) exposure as determined using the Database for Annotation, Visualization and Integrated Discovery 2.1 (DAVID) (Dennis et al., Genome Biol 2003;4(5):P3). MMA(III) also caused dose-dependent changes in multiple Rho guanine nucleotide triphosphatase (GTPase) and cell cycle related genes as determined by linear regression analyses. Observed increases in transcript abundance of Fosl1, Myc, and Rac1 oncogenes in mouse skin support previous reports on the inducibility of these oncogenes in response to arsenic and support the relevance of these genomic changes in skin tumor induction in the K6/ODC mouse model.
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Affiliation(s)
- Don A Delker
- National Health and Environmental Effects Research Laboratory, Office of Research and Development Environmental Carcinogenesis Division, United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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8
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MIYASHITA S, KAISE T. Biological Effects and Metabolism of Arsenic Compounds Present in Seafood Products. Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi) 2010; 51:71-91. [DOI: 10.3358/shokueishi.51.71] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Nelson GM, Ahlborn GJ, Allen JW, Ren H, Corton JC, Waalkes MP, Kitchin KT, Diwan BA, Knapp G, Delker DA. Transcriptional changes associated with reduced spontaneous liver tumor incidence in mice chronically exposed to high dose arsenic. Toxicology 2009; 266:6-15. [PMID: 19822182 DOI: 10.1016/j.tox.2009.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 09/14/2009] [Accepted: 10/04/2009] [Indexed: 12/16/2022]
Abstract
Exposure of male C3H mice in utero (from gestational days 8-18) to 85ppm sodium arsenite via the dams' drinking water has previously been shown to increase liver tumor incidence by 2 years of age. However, in our companion study (Ahlborn et al., 2009), continuous exposure to 85ppm sodium arsenic (from gestational day 8 to postnatal day 365) did not result in increased tumor incidence, but rather in a significant reduction (0% tumor incidence). The purpose of the present study was to examine the gene expression responses that may lead to the apparent protective effect of continuous arsenic exposure. Genes in many functional categories including cellular growth and proliferation, gene expression, cell death, oxidative stress, protein ubiquitination, and mitochondrial dysfunction were altered by continuous arsenic treatment. Many of these genes are known to be involved in liver cancer. One such gene associated with rodent hepatocarcinogenesis, Scd1, encodes stearoyl-CoA desaturase and was down-regulated by continuous arsenic treatment. An overlap between the genes in our study affected by continuous arsenic exposure and those from the literature affected by long-term caloric restriction suggests that reduction in the spontaneous tumor incidence under both conditions may involve similar gene pathways such as fatty acid metabolism, apoptosis, and stress response.
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Affiliation(s)
- Gail M Nelson
- United States Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711, United States
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Ahlborn GJ, Nelson GM, Grindstaff RD, Waalkes MP, Diwan BA, Allen JW, Kitchin KT, Preston RJ, Hernandez-Zavala A, Adair B, Thomas DJ, Delker DA. Impact of life stage and duration of exposure on arsenic-induced proliferative lesions and neoplasia in C3H mice. Toxicology 2009; 262:106-13. [PMID: 19450653 PMCID: PMC3496158 DOI: 10.1016/j.tox.2009.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 05/01/2009] [Accepted: 05/06/2009] [Indexed: 12/31/2022]
Abstract
Epidemiological studies suggest that chronic exposure to inorganic arsenic is associated with cancer of the skin, urinary bladder and lung as well as the kidney and liver. Previous experimental studies have demonstrated increased incidence of liver, lung, ovary, and uterine tumors in mice exposed to 85 ppm (approximately 8 mg/kg) inorganic arsenic during gestation. To further characterize age susceptibility to arsenic carcinogenesis we administered 85 ppm inorganic arsenic in drinking water to C3H mice during gestation, prior to pubescence and post-pubescence to compare proliferative lesion and tumor outcomes over a one-year exposure period. Inorganic arsenic significantly increased the incidence of hyperplasia in urinary bladder (48%) and oviduct (36%) in female mice exposed prior to pubescence (beginning on postnatal day 21 and extending through one year) compared to control mice (19 and 5%, respectively). Arsenic also increased the incidence of hyperplasia in urinary bladder (28%) of female mice continuously exposed to arsenic (beginning on gestation day 8 and extending though one year) compared to gestation only exposed mice (0%). In contrast, inorganic arsenic significantly decreased the incidence of tumors in liver (0%) and adrenal glands (0%) of male mice continuously exposed from gestation through one year, as compared to levels in control (30 and 65%, respectively) and gestation only (33 and 55%, respectively) exposed mice. Together, these results suggest that continuous inorganic arsenic exposure at 85 ppm from gestation through one year increases the incidence and severity of urogenital proliferative lesions in female mice and decreases the incidence of liver and adrenal tumors in male mice. The paradoxical nature of these effects may be related to altered lipid metabolism, the effective dose in each target organ, and/or the shorter one-year observational period.
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Affiliation(s)
- Gene J. Ahlborn
- United States Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC
- North Carolina State University, College of Veterinary Medicine, Department of Molecular Biomedical Sciences, Raleigh, NC
| | - Gail M. Nelson
- United States Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC
| | - Rachel D. Grindstaff
- United States Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC
| | - Michael P. Waalkes
- National Cancer Institute at NIEHS, Laboratory of Comparative Carcinogenesis, Research Triangle Park, NC
| | | | - James W. Allen
- United States Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC
| | - Kirk T. Kitchin
- United States Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC
| | - R. Julian Preston
- United States Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC
| | - Araceli Hernandez-Zavala
- Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina, Chapel Hill, NC
| | - Blakely Adair
- United States Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC
| | - David J. Thomas
- United States Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC
| | - Don A. Delker
- United States Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC
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Ding W, Hudson LG, Sun X, Feng C, Liu KJ. As(III) inhibits ultraviolet radiation-induced cyclobutane pyrimidine dimer repair via generation of nitric oxide in human keratinocytes. Free Radic Biol Med 2008; 45:1065-72. [PMID: 18621123 PMCID: PMC2583127 DOI: 10.1016/j.freeradbiomed.2008.06.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 05/17/2008] [Accepted: 06/18/2008] [Indexed: 11/26/2022]
Abstract
Inorganic arsenic enhances skin tumor formation when combined with other carcinogens including ultraviolet radiation (UVR). The inhibition of DNA damage repair by arsenic has been hypothesized to contribute to the cocarcinogenic activities of arsenic observed in vivo. Cyclobutane pyrimidine dimers (CPDs) are an important mutagenic UVR photoproduct and implicated in the genesis of nonmelanoma skin cancer. The current study demonstrates that low concentrations of arsenite (As(III)) inhibit UVR-induced CPD repair in a human keratinocyte cell line via nitric oxide (NO) and inducible nitric oxide synthase (iNOS). Following As(III) treatment, NO production and iNOS expression are elevated. Little is known about regulation of iNOS by As(III) and further investigations indicated that p38 mitogen-activated protein kinase (p38 MAPK) and NF-kappaB are required for As(III) induction of iNOS expression. This As(III)-stimulated signaling cascade was involved in inhibition of UVR-induced CPD repair as disruption of p38 MAPK activity and NF-kappaB nuclear translocation counteracted the effects of As(III) on CPD repair. Selective inhibition of iNOS ameliorated As(III) inhibition of CPD repair, thereby suggesting that iNOS is a downstream mediator of As(III) activity. These findings provide evidence that an As(III)-stimulated signal transduction cascade culminating in elevated iNOS expression and NO generation is an underlying mechanism for inhibition of UVR-induced DNA damage repair by arsenic.
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Affiliation(s)
| | - Laurie G. Hudson
- Department of Pharmaceutical Sciences, University of New Mexico, Albuquerque, NM, USA, 87131
| | - Xi Sun
- Department of Pharmaceutical Sciences, University of New Mexico, Albuquerque, NM, USA, 87131
| | - Changjian Feng
- Department of Pharmaceutical Sciences, University of New Mexico, Albuquerque, NM, USA, 87131
| | - Ke Jian Liu
- Department of Pharmaceutical Sciences, University of New Mexico, Albuquerque, NM, USA, 87131
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12
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Cohen SM, Arnold LL, Eldan M, Lewis AS, Beck BD. Methylated Arsenicals: The Implications of Metabolism and Carcinogenicity Studies in Rodents to Human Risk Assessment. Crit Rev Toxicol 2008; 36:99-133. [PMID: 16736939 DOI: 10.1080/10408440500534230] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Monomethylarsonic acid (MMA(V)) and dimethylarsinic acid (DMA(V)) are active ingredients in pesticidal products used mainly for weed control. MMA(V) and DMA(V) are also metabolites of inorganic arsenic, formed intracellularly, primarily in liver cells in a metabolic process of repeated reductions and oxidative methylations. Inorganic arsenic is a known human carcinogen, inducing tumors of the skin, urinary bladder, and lung. However, a good animal model has not yet been found. Although the metabolic process of inorganic arsenic appears to enhance the excretion of arsenic from the body, it also involves formation of methylated compounds of trivalent arsenic as intermediates. Trivalent arsenicals (whether inorganic or organic) are highly reactive compounds that can cause cytotoxicity and indirect genotoxicity in vitro. DMA(V) was found to be a bladder carcinogen only in rats and only when administered in the diet or drinking water at high doses. It was negative in a two-year bioassay in mice. MMA(V) was negative in 2-year bioassays in rats and mice. The mode of action for DMA(V)-induced bladder cancer in rats appears to not involve DNA reactivity, but rather involves cytotoxicity with consequent regenerative proliferation, ultimately leading to the formation of carcinoma. This critical review responds to the question of whether DMA(V)-induced bladder cancer in rats can be extrapolated to humans, based on detailed comparisons between inorganic and organic arsenicals, including their metabolism and disposition in various animal species. The further metabolism and disposition of MMA(V) and DMA(V) formed endogenously during the metabolism of inorganic arsenic is different from the metabolism and disposition of MMA(V) and DMA(V) from exogenous exposure. The trivalent arsenicals that are cytotoxic and indirectly genotoxic in vitro are hardly formed in an organism exposed to MMA(V) or DMA(V) because of poor cellular uptake and limited metabolism of the ingested compounds. Furthermore, the evidence strongly supports a nonlinear dose-response relationship for the biologic processes involved in the carcinogenicity of arsenicals. Based on an overall review of the evidence, using a margin-of-exposure approach for MMA(V) and DMA(V) risk assessment is appropriate. At anticipated environmental exposures to MMA(V) and DMA(V), there is not likely to be a carcinogenic risk to humans.
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Affiliation(s)
- Samuel M Cohen
- Department of Pathology and Microbiology and Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, Nebraska 68198-3135, USA.
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Ahlborn GJ, Nelson GM, Ward WO, Knapp G, Allen JW, Ouyang M, Roop BC, Chen Y, O'Brien T, Kitchin KT, Delker DA. Dose response evaluation of gene expression profiles in the skin of K6/ODC mice exposed to sodium arsenite. Toxicol Appl Pharmacol 2008; 227:400-16. [DOI: 10.1016/j.taap.2007.10.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 10/02/2007] [Accepted: 10/29/2007] [Indexed: 12/13/2022]
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Miller TJ, Honchel R, Espandiari P, Knapton A, Zhang J, Sistare FD, Hanig JP. The utility of the K6/ODC transgenic mouse as an alternative short term dermal model for carcinogenicity testing of pharmaceuticals. Regul Toxicol Pharmacol 2007; 50:87-97. [PMID: 18069108 DOI: 10.1016/j.yrtph.2007.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Revised: 10/16/2007] [Accepted: 10/17/2007] [Indexed: 11/19/2022]
Abstract
The use of transgenic rodents may overcome many limitations of traditional cancer studies. Regulatory perspectives continue to evolve as new models are developed and validated. The transgenic mouse, K6/ODC, develops epidermal tumors when exposed to genotoxic carcinogens. In this study, K6/ODC mice were evaluated for model fitness and health robustness in a 36-week study to determine oncogenic risk of residual DNA in vaccines from neoplastic cell substrates. K6/ODC and C57BL/6 mice were treated with T24-H-ras expression plasmid, carrier vector DNA, or saline topically or by subcutaneous injection. One group of K6/ODC mice received 7,12-dimethylbenz-[a]anthracene [DMBA] dermally. Only DMBA-treated mice developed papillomas by six weeks, increasing in incidence to 25 weeks. By week 11, many K6/ODC mice showed severe dehydration and dermal eczema. By week 32, (6/8) surviving K6/ODC mice showed loss of mobility and balance. Microscopic evaluation of tissues revealed dermal/sebaceous gland hyperplasia, follicular dystrophy, splenic atrophy, and amyloid deposition/neutrophilic infiltration within liver, heart, and spleen, in all K6/ODC mice. Pathology was not detected in C57BL/6 mice. Progressive adverse health, decreased survival, and failure to develop papillomas to the H-ras plasmid suggest that K6/ODC mice may be an inappropriate alternative model for detection of oncogenic DNA and pharmaceutical carcinogenicity testing.
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Affiliation(s)
- T J Miller
- Division of Applied Pharmacology Research, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993-0002, USA.
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15
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Krishnamohan M, Wu HJ, Huang SH, Maddelena R, Lam PKS, Moore MR, Ng JC. Urinary arsenic methylation and porphyrin profile of C57Bl/6J mice chronically exposed to sodium arsenate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2007; 379:235-43. [PMID: 17081589 DOI: 10.1016/j.scitotenv.2006.08.052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 08/28/2006] [Accepted: 08/28/2006] [Indexed: 05/12/2023]
Abstract
Arsenic interferes with the function of enzymes responsible for haem biosynthesis leading to alteration in the porphyrin profile. In this study, young female C57Bl/6J mice were given drinking water containing 0, 100, 250 and 500 microg As(V)/L as sodium arsenate ad libitum for 24 months. 24 h pooled urine samples were collected bimonthly for urinary arsenic methylation and porphyrin analyses by HPLC-ICP-MS and HPLC respectively. The levels of total arsenic were significantly dose related except for the 2nd month interval. No significant differences in the urinary arsenic methylation pattern between control and test groups were observed. Coproporphyrin I (Copro I) showed a significant dose-response relationship after 12, 14 and 20 months of exposure. Significant differences in the levels of coproporphyrin III (Copro III) were observed in the 8th month in 250 and 500 microg/L treatment groups and the dose-response pattern was maintained after 10 and 12 months. Our results suggest that urinary arsenic is a useful biomarker for internal dose, and that urinary coproporphyrin can be used as an early warning biomarker of effects before the onset of cancer.
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Affiliation(s)
- Manonmanii Krishnamohan
- National Research Centre for Environmental Toxicology, The University of Queensland, 39 Kessels Road, Coopers Plains, Brisbane, Qld 4108, Australia
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16
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Jin Y, Xi S, Li X, Lu C, Li G, Xu Y, Qu C, Niu Y, Sun G. Arsenic speciation transported through the placenta from mother mice to their newborn pups. ENVIRONMENTAL RESEARCH 2006; 101:349-55. [PMID: 16458287 DOI: 10.1016/j.envres.2005.11.006] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 11/13/2005] [Accepted: 11/22/2005] [Indexed: 05/06/2023]
Abstract
The primary goal of the present study was to confirm the arsenic species that can be transferred from the mother to the bodies of newborn pups through the placenta and the speciated arsenic distribution in the liver and brain of newborn mice after gestational maternal exposure to inorganic arsenic (iAs). Mother mice were exposed to iAsIII and iAsV in drinking water during gestation. The livers and brains of the mother mice and their newborn pups were taken. Contents of iAs, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and trimethylarsenic (TMA) compound were detected using the HG-AAS method. Contents of iAs, MMA, and DMA in the liver of mother mice increased with the concentration of arsenite or arsenate in their drinking water. However, only DMA increased with the concentration of arsenate or arsenite in the drinking water in the brain of mother mice. On the other hand, contents of both iAs and DMA in the liver and brain of newborn mice increased with the concentration of arsenate or arsenite administered to their mother orally. Contents of arsenic species in the liver and brain of both mother mice and their newborn pups were significantly lower in the 10 ppm iAsV group than in the 10 ppm iAsIII group. Ratios of iAs or DMA levels between the brain and the liver of newborn mice were larger than 1, whereas those in mother mice were much smaller than 1. iAs taken from drinking water was distributed and metabolized mainly in the liver of mother mice. iAsIII in low levels may be taken up and metabolized easily in the liver compared to iAsV. Both iAs and DMA are transferred from the mother through the placenta and cross the immature blood-brain barrier (BBB) easily. Compared to that in the liver of newborn mice, DMA as an organic metabolite is prevalent in brain, a lipidic organ, if the BBB is not matured enough to prevent it from entering the brain.
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Affiliation(s)
- Yaping Jin
- Department of Environmental and Occupational Health, College of Public Health, China Medical University, Shenyang, Liaoning 110001, PR China
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17
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Arnold LL, Eldan M, Nyska A, van Gemert M, Cohen SM. Dimethylarsinic acid: Results of chronic toxicity/oncogenicity studies in F344 rats and in B6C3F1 mice. Toxicology 2006; 223:82-100. [PMID: 16677751 DOI: 10.1016/j.tox.2006.03.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 02/16/2006] [Accepted: 03/13/2006] [Indexed: 10/24/2022]
Abstract
Dimethylarsinic acid (DMA(V), cacodylic acid), a foliar herbicide, was administered in the diet to B6C3F1 mice (at dose levels of 0, 8, 40, 200, and 500 ppm) and to F344 rats (at dose levels of 0, 2, 10, 40, and 100 ppm) for 2 years, according to US EPA guidelines. In mice, there were no treatment-related tumors observed at any site. Treatment-related progressive glomerulonephropathy and nephrocalcinosis were observed in the kidneys in both sexes. The incidence of vacuolation of the epithelium in the urinary bladder was increased in both sexes, but was not associated with cytotoxicity, necrosis or hyperplasia. Based on non-neoplastic lesions found in the urinary bladder, the NOEL for mice was assessed to be 40 ppm in males and 8 ppm in females. In rats, treatment-related mortality occurred early in the study in five males in the 100 ppm group and in one male in the 40 ppm group. Papillomas and carcinomas with degeneration of the urothelium, necrosis and urothelial cell hyperplasia, were found in the urinary bladders of both sexes. In male rats, one papilloma was found in each of the 10 and 40 ppm groups; one urothelial cell carcinoma was found in the 2 ppm group and two in the 100 ppm group. Four papillomas and six urothelial cell carcinomas were found in the female 100 ppm group. Non-neoplastic treatment-related kidney lesions were confined to the 40 and 100 ppm levels and included necrosis, pyelonephritis, medullary nephrocalcinosis and tubular cystic dilation, hyperplasia of the epithelial lining of the papilla, and pelvic urothelial cell hyperplasia. All of these kidney changes appear to be related to an increase in the aging nephropathy of the rat. Dose-related increases in the height of the thyroid follicular epithelium were also noted in males and females, however, such changes reflect an adaptive response of the thyroid to decreased levels of circulating thyroid hormone, rather than an adverse effect. Based on the kidney and bladder lesions, the NOEL for non-neoplastic and neoplastic lesions was considered to be 10 ppm in males and females. Based on these studies, DMA(V) is carcinogenic only in rats and only at relatively high doses, with the urinary bladder as the target organ. Female rats appear to be more sensitive to the effects of DMA(V) than male rats. DMA(V) is not carcinogenic in mice.
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Affiliation(s)
- Lora L Arnold
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
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18
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Shoji Y, Takahashi M, Takasuka N, Niho N, Kitamura T, Sato H, Maruyama T, Sugimoto Y, Narumiya S, Sugimura T, Wakabayashi K. Prostaglandin E receptor EP3 deficiency modifies tumor outcome in mouse two-stage skin carcinogenesis. Carcinogenesis 2005; 26:2116-22. [PMID: 16051640 DOI: 10.1093/carcin/bgi193] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We have recently shown that the prostaglandin E(2) (PGE(2)) receptor EP(3) plays an important role in suppression of colon cancer cell proliferation and that its deficiency enhances late stage colon carcinogenesis. Here we examined the effects of EP(3)-deficiency on two-stage skin carcinogenesis. 7,12-Dimethylbenz[a]anthracene (50 microg/200 microl of acetone) was thus applied to the back skin of female EP(3)-knockout and wild-type mice at 8 weeks of age, followed by treatment with 12-O-tetradecanoylphorbol-13-acetate (5 microg/200 microl of acetone) twice a week for 25 weeks. First tumor appearance was observed in EP(3)-knockout mice at week 10, which was 3 weeks later than in EP(3) wild-type mice, and multiplicity observed at week 11 was significantly lower in the EP(3)-knockout case. However, histological examination showed that the tumor incidence and multiplicity at week 25 were not significantly changed in knockout mice and wild-type mice (incidence, 19/19 versus 23/24; multiplicity, 3.58 +/- 0.51 versus 3.17 +/- 0.63, respectively). Interestingly, there were no squamous cell carcinomas (SCCs) in the EP(3)-knockout mice, while SCCs were observed in 3 out of 24 wild-type mice. Furthermore, benign keratoacanthomas only developed in EP(3)-knockout mice (6/19 versus 0/24, P < 0.01). The results suggest that PGE(2) receptor EP(3) signaling might contribute to development of SCCs in the skin.
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MESH Headings
- 9,10-Dimethyl-1,2-benzanthracene/toxicity
- Animals
- Cadherins/metabolism
- Carcinoma, Squamous Cell/chemically induced
- Carcinoma, Squamous Cell/metabolism
- Carcinoma, Squamous Cell/pathology
- Female
- Incidence
- Keratoacanthoma/chemically induced
- Keratoacanthoma/metabolism
- Keratoacanthoma/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Prostaglandin E/genetics
- Receptors, Prostaglandin E/physiology
- Receptors, Prostaglandin E, EP3 Subtype
- Reverse Transcriptase Polymerase Chain Reaction
- Skin Neoplasms/chemically induced
- Skin Neoplasms/metabolism
- Skin Neoplasms/pathology
- Tetradecanoylphorbol Acetate/toxicity
- Treatment Outcome
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Affiliation(s)
- Yutaka Shoji
- Cancer Prevention Basic Research Project, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan
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19
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Mizoi M, Takabayashi F, Nakano M, An Y, Sagesaka Y, Kato K, Okada S, Yamanaka K. The role of trivalent dimethylated arsenic in dimethylarsinic acid-promoted skin and lung tumorigenesis in mice: tumor-promoting action through the induction of oxidative stress. Toxicol Lett 2005; 158:87-94. [PMID: 16039397 DOI: 10.1016/j.toxlet.2005.03.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Revised: 03/01/2005] [Accepted: 03/01/2005] [Indexed: 11/16/2022]
Abstract
We investigated the relationship between lung- and skin-tumor promotion and oxidative stress caused by administration of dimethylarsinic acid (DMA(V)) in mice. The incidence of lung tumors induced by lung tumor initiator (4NQO) and DMA(V) were, as well as 8-oxo-2'-deoxyguanosine (8-oxodG), suppressed by cotreatment with (-)epigallocatechin gallate (EGCG). When mice were topically treated with trivalent dimethylated arsenic (DMA(III)), a further reductive metabolite of DMA(V), not only an increase in skin tumors but also an elevation of 8-oxodG in epidermis were observed. These results suggest that tumor promotion due to DMA(V) administration is mediated by DMA(III) through the induction of oxidative stress.
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Affiliation(s)
- Mutsumi Mizoi
- Department of Environmental Toxicology and Carcinogenesis, Nihon University College of Pharmacy, 7-7-1 Narashinodai, Funabashi, Chiba 274-8555, Japan
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20
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Motiwale L, Ingle AD, Rao KVK. Mouse skin tumor promotion by sodium arsenate is associated with enhanced PCNA expression. Cancer Lett 2004; 223:27-35. [PMID: 15890234 DOI: 10.1016/j.canlet.2004.10.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Revised: 10/08/2004] [Accepted: 10/12/2004] [Indexed: 10/26/2022]
Abstract
Drinking water contamination by arsenicals remains a major public health problem in many parts of the world more particularly in India and Bangladesh. Despite arsenic being a health hazard and implicated in human carcinogenesis, the experimental evidence available is much limited even now and the mechanisms involved during carcinogenesis and tumor promotions are not clear. Accordingly, in this study, we have studied the tumor promoter effects of sodium arsenate on mouse skin tumor promoter model system using 9,10-dimethyl-1,2-benzanthracene (DMBA) as a initiating carcinogen. Our studies showed development of papillomas on mice skin treated with only DMBA. However, mice treated with DMBA on skin and administered arsenate (As) in drinking water showed development of well differentiated squamous cell carcinomas. Further, both by immunohistochemistry and western blotting analysis studies higher levels of proliferating cell nuclear antigen (PCNA) was observed in mice treated with DMBA plus arsenate compared to only DMBA treated group. PCNA is known to be associated with S phase and DNA replication of the cell cycle. The plain controls and arsenate controls did not show significant difference either in tumor development or in PCNA levels. The present study demonstrates mouse skin tumor promoting effect of arsenate which seems to be associated with abnormal cell proliferation as indicated by higher levels of PCNA expression.
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Affiliation(s)
- L Motiwale
- Chemical Carcinogenesis Group, Cancer Research Institute, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410 208, India
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21
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Wanibuchi H, Salim EI, Kinoshita A, Shen J, Wei M, Morimura K, Yoshida K, Kuroda K, Endo G, Fukushima S. Understanding arsenic carcinogenicity by the use of animal models. Toxicol Appl Pharmacol 2004; 198:366-76. [PMID: 15276416 DOI: 10.1016/j.taap.2003.10.032] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2003] [Accepted: 10/08/2003] [Indexed: 12/22/2022]
Abstract
Although numerous epidemiological studies have indicated that human arsenic exposure is associated with increased incidences of bladder, liver, skin, and lung cancers, limited attempts have been made to understand mechanisms of carcinogenicity using animal models. Dimethylarsinic acid (DMA), an organic arsenic compound, is a major metabolite of ingested inorganic arsenics in mammals. Recent in vitro studies have proven DMA to be a potent clastogenic agent, capable of inducing DNA damage including double strand breaks and cross-link formation. In our attempts to clarify DMA carcinogenicity, we have recently shown carcinogenic effects of DMA and its related metabolites using various experimental protocols in rats and mice: (1) a multi-organ promotion bioassay in rats; (2) a two-stage promotion bioassay by DMA of rat urinary bladder and liver carcinogenesis; (3) a 2-year carcinogenicity test of DMA in rats; (4) studies on the effects of DMA on lung carcinogenesis in rats; (5) promotion of skin carcinogenesis by DMA in keratin (K6)/ornithine decarboxylase (ODC) transgenic mice; (6) carcinogenicity of DMA in p53(+/-) knockout and Mmh/8-OXOG-DNA glycolase (OGG1) mutant mice; (7) promoting effects of DMA and related organic arsenicals in rat liver; (8) promoting effects of DMA and related organic arsenicals in a rat multi-organ carcinogenesis test; and (9) 2-year carcinogenicity tests of monomethylarsonic acid (MMA) and trimethylarsine oxide (TMAO) in rats. The results revealed that the adverse effects of arsenic occurred either by promoting and initiating carcinogenesis. These data, as covered in the present review, suggest that several mechanisms may be involved in arsenic carcinogenesis.
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Affiliation(s)
- Hideki Wanibuchi
- Department of Pathology, Osaka City University Medical School, Osaka 545-8585, Japan.
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22
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Niwa Y, Terashima T, Sumi H. Topical application of the immunosuppressant tacrolimus accelerates carcinogenesis in mouse skin. Br J Dermatol 2004; 149:960-7. [PMID: 14632799 DOI: 10.1111/j.1365-2133.2003.05735.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Tacrolimus, produced by the fungus Streptomyces tsukabaensis, is a potent macrolide immunosuppressant widely used in liver and kidney transplantation. Topical tacrolimus has recently been found to be an effective treatment for atopic dermatitis (AD). OBJECTIVES Because of the well-known association between T-cell immunosuppression and an increased risk of carcinogenesis, we investigated the effect of topical tacrolimus on skin carcinogenesis in 117 mice. METHODS Approximately 8 cm2 of the shaved dorsal skin of 7-week-old female CD-1 mice was treated with 7,12-dimethylbenz[alpha]anthracene (DMBA) dissolved in acetone, which is in general use as a tumour initiator, or acetone alone, on day 1 of the experiment, followed by promoting treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) with or without tacrolimus, or acetone with or without tacrolimus, for 20 weeks. The mice were divided into six treatment groups: (1) DMBA followed by acetone; (2) DMBA followed by TPA; (3) DMBA followed by acetone + tacrolimus; (4) DMBA followed by TPA + tacrolimus; (5) acetone followed by acetone + tacrolimus; and (6) acetone followed by acetone (control). RESULTS The induction of skin tumours was significantly greater in the TPA-treated groups than in the absence of TPA. However, after 14 weeks there was marked synergy between tacrolimus and the DMBA/TPA regimen, with 0.47 +/- 0.13 (mean +/- SD) new tumours per mouse per week in group 4 vs. 0.10 +/- 0.025 in group 2 (P < 0.01), and 0.01 +/- 0.002 in group 3. A significant reduction in the CD4/CD8 ratio was found in axillary and inguinal lymph nodes in tacrolimus-treated mice, supporting the presumption that the immunosuppressive effect of the drug was responsible for its effect in promoting tumorigenesis. The major increase in tumours caused by topical tacrolimus was of papillomas, not squamous cell carcinomas. Papillomas are uncommon in humans, and are benign. However, 8.5% of the tumours found in the experiment were squamous cell carcinomas, and a considerable synergy between topical tacrolimus and conventional carcinogens was observed, raising the spectre of some risk of skin carcinogenesis in AD patients undergoing prolonged treatment with tacrolimus. CONCLUSIONS Caution and careful surveillance are required with regard to skin lesions in patients treated with tacrolimus for prolonged periods.
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Affiliation(s)
- Y Niwa
- Niwa Institute for Immunology, 4-4 Asahimachi, Tosashimizu, Kochi-ken 787-0303, Japan.
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23
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Shen J, Wanibuchi H, Salim EI, Wei M, Doi K, Yoshida K, Endo G, Morimura K, Fukushima S. Induction of glutathione S-transferase placental form positive foci in liver and epithelial hyperplasia in urinary bladder, but no tumor development in male Fischer 344 rats treated with monomethylarsonic acid for 104 weeks. Toxicol Appl Pharmacol 2003; 193:335-45. [PMID: 14678743 DOI: 10.1016/s0041-008x(03)00245-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The carcinogenicity of monomethylarsonic acid (MMA(V)), a major metabolite of inorganic arsenics in human and experimental animals, was investigated in male Fischer 344 rats. A total of 129 rats at 10 weeks of age were randomly divided into three groups and received drinking water containing MMA(V) at doses of 0 (Control), 50, and 200 ppm ad libitum for 104 weeks. No significant differences were found between the control and the MMA(V)-treated groups regarding clinical signs, mortality, hematological, and serum biochemistry findings. Quantitative analysis of glutathione S-transferase placental form (GST-P) positive foci in liver revealed a significant increase of numbers and areas in the 200 ppm MMA(V)-treated group. In the urinary bladder MMA(V) induced simple hyperplasia and significantly elevated the proliferating cell nuclear antigen (PCNA)-positive index in the urothelium. A variety of tumors developed in rats of all groups, including the controls, but all were histologically similar to those known to occur spontaneously in F344 rats and there were no significant differences among the groups. Thus, it could be concluded that, under the present experimental conditions, MMA(V) induced lesions in the liver and urinary bladder, but did not cause tumor development in male F344 rats even after 2 years exposure.
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Affiliation(s)
- Jun Shen
- Department of Pathology, Osaka City University Medical School, 1-4-3, Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
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24
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Waalkes MP, Ward JM, Liu J, Diwan BA. Transplacental carcinogenicity of inorganic arsenic in the drinking water: induction of hepatic, ovarian, pulmonary, and adrenal tumors in mice. Toxicol Appl Pharmacol 2003; 186:7-17. [PMID: 12583988 DOI: 10.1016/s0041-008x(02)00022-4] [Citation(s) in RCA: 254] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Arsenic is a known human carcinogen, but development of rodent models of inorganic arsenic carcinogenesis has been problematic. Since gestation is often a period of high sensitivity to chemical carcinogenesis, we performed a transplacental carcinogenicity study in mice using inorganic arsenic. Groups (n = 10) of pregnant C3H mice were given drinking water containing sodium arsenite (NaAsO(2)) at 0 (control), 42.5, and 85 ppm arsenite ad libitum from day 8 to 18 of gestation. These doses were well tolerated and body weights of the dams during gestation and of the offspring subsequent to birth were not reduced. Dams were allowed to give birth, and offspring were weaned at 4 weeks and then put into separate gender-based groups (n = 25) according to maternal exposure level. The offspring received no additional arsenic treatment. The study lasted 74 weeks in males and 90 weeks in females. A complete necropsy was performed on all mice and tissues were examined by light microscopy in a blind fashion. In male offspring, there was a marked increase in hepatocellular carcinoma incidence in a dose- related fashion (control, 12%; 42.5 ppm, 38%; 85 ppm, 61%) and in liver tumor multiplicity (tumors per liver; 5.6-fold over control at 85 ppm). In males, there was also a dose-related increase in adrenal tumor incidence and multiplicity. In female offspring, dose-related increases occurred in ovarian tumor incidence (control, 8%; 42.5 ppm, 26%; 85 ppm, 38%) and lung carcinoma incidence (control, 0%; 42.5 ppm, 4%; 85 ppm, 21%). Arsenic exposure also increased the incidence of proliferative lesions of the uterus and oviduct. These results demonstrate that oral inorganic arsenic exposure, as a single agent, can induce tumor formation in rodents and establishes inorganic arsenic as a complete transplacental carcinogen in mice. The development of this rodent model of inorganic arsenic carcinogenesis has important implications in defining the mechanism of action for this common environmental carcinogen.
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Affiliation(s)
- Michael P Waalkes
- Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
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25
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Trouba KJ, Geisenhoffer KM, Germolec DR. Sodium arsenite-induced stress-related gene expression in normal human epidermal, HaCaT, and HEL30 keratinocytes. ENVIRONMENTAL HEALTH PERSPECTIVES 2002; 110 Suppl 5:761-6. [PMID: 12426128 PMCID: PMC1241241 DOI: 10.1289/ehp.02110s5761] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Arsenic is a carcinogen that poses a significant health risk in humans. Based on evidence that arsenic has differential effects on human, rodent, normal, and transformed cells, these studies addressed the relative merits of using normal human epidermal keratinocytes (NHEK) and immortalized human (HaCaT) and mouse (HEL30) keratinocytes when examining stress-induced gene expression that may contribute to carcinogenesis. We hypothesize that redox-related gene expression is differentially modulated by arsenic in normal versus immortalized keratinocytes. To test the hypothesis, we exposed keratinocytes to sodium arsenite for 4 or 24 hr, at which time serine threonine kinase-25 (stk25) and nicotine adenine dinucleotide phosphate [nad(p)h] quinone oxidoreductase gene expression were measured. The effect of glutathione reduction on arsenite-induced cytotoxicity and gene expression in NHEK also was evaluated by addition of l-buthionine-[S,R]-sulfoximine (BSO) to culture media. Results indicate the term LC(50) for arsenite is approximately 10-15 microM in NHEK and HEL30 keratinocytes and 30 microM in HaCaT keratinocytes. Compared with HaCaT and HEL30 keratinocytes, a nontoxic concentration of arsenite (2.5 microM) increases stk25 and nad(p)h quinone oxidoreductase gene expression in NHEK, an effect partially attenuated by BSO. These data indicate that NHEK and HaCaT/HEL30 keratinocytes have similar sensitivities toward arsenite-induced cytotoxicity but unique gene expression responses. They also suggest that arsenite modulates gene expression in NHEK involved in cellular signaling and other aspects of intermediary metabolism that may contribute to the carcinogenic process.
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Affiliation(s)
- Kevin J Trouba
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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26
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Nishikawa T, Wanibuchi H, Ogawa M, Kinoshita A, Morimura K, Hiroi T, Funae Y, Kishida H, Nakae D, Fukushima S. Promoting effects of monomethylarsonic acid, dimethylarsinic acid and trimethylarsine oxide on induction of rat liver preneoplastic glutathione S-transferase placental form positive foci: a possible reactive oxygen species mechanism. Int J Cancer 2002; 100:136-9. [PMID: 12115560 DOI: 10.1002/ijc.10471] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Dimethylarsinic acid (DMA) is a major metabolite of inorganic arsenicals, which are epidemiologically significant chemicals in relation to liver cancer in mammals. The present study was conducted to determine the promoting effects of organic arsenicals related to DMA [monomethylarsonic acid (MMA) and trimethylarsine oxide (TMAO)] on rat liver carcinogenesis using a liver medium-term bioassay (the Ito test). Male, 10-week-old, F344 rats were given a single i.p. injection of diethylnitrosamine at a dose of 200 mg/kg b.w. as an initiator. Starting 2 weeks thereafter they received 100 ppm of MMA, DMA or TMAO in their drinking water, or no supplement as a control, for 6 weeks. All animals underwent 2/3 partial hepatectomy in week 3 after initiation. Quantification of glutathione S-transferase placental form (GST-P)-positive foci as preneoplastic lesions in liver sections revealed significantly increased numbers and areas in all 3 treated groups compared with controls. Hepatic microsome cytochrome P-450 content was markedly increased with all 3 arsenic treatments. Markedly elevated CYP 2B1 protein levels and CYP 2B1/2 mRNA levels were thus observed in all cases. The potency of promotion was similar for MMA, DMA and TMAO. Since hydroxyradicals were found to be generated in the relatively early phase while methylated arsenicals were metabolized in liver, the resultant oxidative stress might have promoted lesion development.
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Affiliation(s)
- Takayuki Nishikawa
- Department of Pathology, Osaka City University Medical School, Osaka, Japan
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27
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Abstract
As inorganic arsenic is a proven human carcinogen, significant effort has been made in recent decades in an attempt to understand arsenic carcinogenesis using animal models, including rodents (rats and mice) and larger mammals such as beagles and monkeys. Transgenic animals were also used to test the carcinogenic effect of arsenicals, but until recently all models had failed to mimic satisfactorily the actual mechanism of arsenic carcinogenicity. However, within the past decade successful animal models have been developed using the most common strains of mice or rats. Thus dimethylarsinic acid (DMA), an organic arsenic compound which is the major metabolite of inorganic arsenicals in mammals, has been proven to be tumorigenic in such animals. Reports of successful cancer induction in animals by inorganic arsenic (arsenite and arsenate) have been rare, and most carcinogenetic studies have used organic arsenicals such as DMA combined with other tumor initiators. Although such experiments used high concentrations of arsenicals for the promotion of tumors, animal models using doses of arsenicals species closed to the exposure level of humans in endemic areas are obviously the most significant. Almost all researchers have used drinking water or food as the pathway for the development of animal model test systems in order to mimic chronic arsenic poisoning in humans; such pathways seem more likely to achieve desirable results.
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Affiliation(s)
- Jian Ping Wang
- National Research Center for Environmental Toxicology, University of Queensland, 39 Kessels Road, Coopers Plains, Brisbane, Qld 4108, Australia
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28
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Bode AM, Dong Z. The paradox of arsenic: molecular mechanisms of cell transformation and chemotherapeutic effects. Crit Rev Oncol Hematol 2002; 42:5-24. [PMID: 11923065 DOI: 10.1016/s1040-8428(01)00215-3] [Citation(s) in RCA: 186] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Arsenic is a well-documented carcinogen that also appears to be a valuable therapeutic tool in cancer treatment. This creates a paradox for which no unified hypothesis has been reached regarding the molecular mechanisms that determine whether arsenic will act as a carcinogen or as an effectual chemotherapeutic agent. Much of our knowledge with respect to the actions of arsenic has been drawn from epidemiological or clinical studies. The actions of arsenic are likely to be related to cell type, arsenic species, and length and dose of exposure. Arsenic unquestionably induces apoptosis and may specifically target certain tumor cells. Research data strongly suggest that arsenic influences distinct signaling pathways involved in mediating proliferation or apoptosis, including mitogen-activated protein kinases, p53, activator protein-1 or nuclear factor kappa B. The primary purpose of this review is to examine recent findings, from this laboratory and others, that focus on the molecular mechanisms of arsenic's actions in cell transformation and as a therapeutic agent.
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Affiliation(s)
- Ann M Bode
- The Hormel Institute, University of Minnesota, 801 16th Avenue NE, Austin, MN 55912, USA
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29
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Namgung U, Xia Z. Arsenic induces apoptosis in rat cerebellar neurons via activation of JNK3 and p38 MAP kinases. Toxicol Appl Pharmacol 2001; 174:130-8. [PMID: 11446828 DOI: 10.1006/taap.2001.9200] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Primary cultures of rat cerebellar neurons were used to study mechanisms of arsenic neurotoxicity. Exposure to 5, 10, or 15 microM sodium arsenite reduced cerebellar neuron viability and induced nuclear fragmentation and condensation as well as DNA degradation to oligonucleosome fragments. Exposure to 1 or 5 mM dimethylarsinic acid caused similar changes. Therefore, both inorganic arsenite and organic dimethylarsinic acid induce apoptosis in cerebellar neurons, with the inorganic form being more toxic. Cotreatment with cycloheximide or actinomycin D, inhibitors of protein or RNA synthesis, respectively, or with the caspase inhibitor zVAD, completely blocked arsenite-induced cerebellar neuron apoptosis. This implies that arsenite-induced cerebellar neuron apoptosis requires new gene expression and caspase activation. Interestingly, sodium arsenite selectively activated p38 and JNK3, but not JNK1 or JNK2 in cerebellar neurons. Blocking the p38 or JNK signaling pathways using the inhibitors SB203580 or CEP-1347 protected cerebellar neurons against arsenite-induced apoptosis. These data suggest that arsenite neurotoxicity may be due to apoptosis caused by activation of p38 and JNK3 MAP kinases.
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Affiliation(s)
- U Namgung
- Department of Environmental Health, University of Washington, Seattle, Washington 98195-7234, USA
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30
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Kitchin KT. Recent advances in arsenic carcinogenesis: modes of action, animal model systems, and methylated arsenic metabolites. Toxicol Appl Pharmacol 2001; 172:249-61. [PMID: 11312654 DOI: 10.1006/taap.2001.9157] [Citation(s) in RCA: 489] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent advances in our knowledge of arsenic carcinogenesis include the development of rat or mouse models for all human organs in which inorganic arsenic is known to cause cancer-skin, lung, urinary bladder, liver, and kidney. Tumors can be produced from either promotion of carcinogenesis protocols (mouse skin and lungs, rat bladder, kidney, liver, and thyroid) or from complete carcinogenesis protocols (rat bladder and mouse lung). Experiments with p53(+/-) and K6/ODC transgenic mice administered dimethylarsinic acid or arsenite have shown some degree of carcinogenic, cocarcinogenic, or promotional activity in skin or bladder. At present, with the possible exception of skin, the arsenic carcinogenesis models in wild-type animals are more highly developed than in transgenic mice. Recent advances in arsenic metabolism have suggested that methylation of inorganic arsenic may be a toxification, rather than a detoxification, pathway and that trivalent methylated arsenic metabolites, particularly monomethylarsonous acid and dimethylarsinous acid, have a great deal of biological activity. Accumulating evidence indicates that these trivalent, methylated, and relatively less ionizable arsenic metabolites may be unusually capable of interacting with cellular targets such as proteins and even DNA. In risk assessment of environmental arsenic, it is important to know and to utilize both the mode of carcinogenic action and the shape of the dose-response curve at low environmental arsenic concentrations. Although much progress has been recently made in the area of arsenic's possible mode(s) of carcinogenic action, a scientific concensus has not yet been reached. In this review, nine different possible modes of action of arsenic carcinogenesis are presented and discussed-induced chromosomal abnormalities, oxidative stress, altered DNA repair, altered DNA methylation patterns, altered growth factors, enhanced cell proliferation, promotion/progression, gene amplification, and suppression of p53.
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Affiliation(s)
- K T Kitchin
- Environmental Carcinogenesis Division, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
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31
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Yamanaka K, Mizol M, Kato K, Hasegawa A, Nakano M, Okada S. Oral administration of dimethylarsinic acid, a main metabolite of inorganic arsenic, in mice promotes skin tumorigenesis initiated by dimethylbenz(a)anthracene with or without ultraviolet B as a promoter. Biol Pharm Bull 2001; 24:510-4. [PMID: 11379771 DOI: 10.1248/bpb.24.510] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Concerning arsenic-induced tumorigenesis, an animal model must be developed for understanding the mechanism of human carcinogenesis by arsenics. To determine whether orally administered dimethylarsinic acid (DMA) promotes and causes the progression of skin tumorigenesis, an animal protocol by topical application of dimethylbenz(a)anthracene (DMBA) with or without UVB, a tumor promoter, in hairless mice was used. The administration of DMA by the oral route promoted not only the formation of papillomas induced by DMBA alone but also the formation of malignant tumors induced by way of the formation of atypical keratoses by treatment with DMBA and UVB. A phenomenon, the progression of keratoses-->atypical keratoses-->squamous cell carcinomas (SCCs), observed in the present study may resemble the development of tumors in arsenic-exposed humans. We also discussed the involvement of a reactive oxygen species (ROS), e.g., the dimethylarsenic peroxy radical [(CH3)2AsOO.], produced during the metabolic processing of DMA, in skin and in multi-organ tumorigenesis.
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Affiliation(s)
- K Yamanaka
- College of Pharmacy, Nihon University, Funabashi, Chiba, Japan.
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