51
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Chai CY, Huang YC, Hung WC, Kang WY, Chen WT. Arsenic salts induced autophagic cell death and hypermethylation of DAPK promoter in SV-40 immortalized human uroepithelial cells. Toxicol Lett 2007; 173:48-56. [PMID: 17683884 DOI: 10.1016/j.toxlet.2007.06.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 06/15/2007] [Accepted: 06/15/2007] [Indexed: 12/31/2022]
Abstract
Arsenic is a well-known toxic and carcinogenic agent, and associated with various human malignancies, including skin, lung and bladder cancers. Paradoxically, arsenic trioxide has been used successfully in the treatment of patients with acute promyelocytic leukemia. In addition, arsenic could induce cell apoptosis or autophagy in malignant cells. However, the underlying mechanism of arsenic-induced carcinogenesis is still unclear. In this study, we demonstrated an increase of autophagosomes was produced in arsenic-treated SV-HUC-1 cells by using electron microscopy. In addition, increase of Beclin-1, an important regulator for the formation of autophagosome, protein expression in a dose-dependent manner was also found. By using methylation specific PCR, we revealed hypermethylation of CpG sites in the promoter region with decreased DAPK protein expression in arsenic-treated SV-HUC-1 cells. As epigenetic silencing of tumor suppressor genes by promoter hypermethylation has been found in a variety of malignancies including bladder cancer, our results provide new insights for the understanding of the mechanism of arsenic-induced carcinogenesis in urothelial cells.
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MESH Headings
- Apoptosis Regulatory Proteins/genetics
- Apoptosis Regulatory Proteins/metabolism
- Arsenites/toxicity
- Autophagy/drug effects
- Beclin-1
- Blotting, Western
- Calcium-Calmodulin-Dependent Protein Kinases/genetics
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Carcinogens/toxicity
- Cell Line, Transformed
- Cell Survival/drug effects
- Cell Transformation, Neoplastic/drug effects
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Cell Transformation, Viral
- CpG Islands/drug effects
- DNA Methylation/drug effects
- Death-Associated Protein Kinases
- Dose-Response Relationship, Drug
- Humans
- Immunohistochemistry
- Membrane Proteins/metabolism
- Microscopy, Electron, Transmission
- Polymerase Chain Reaction
- Promoter Regions, Genetic/drug effects
- Simian virus 40
- Sodium Compounds/toxicity
- Up-Regulation
- Urothelium/drug effects
- Urothelium/enzymology
- Urothelium/metabolism
- Urothelium/ultrastructure
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Affiliation(s)
- Chee-Yin Chai
- Department of Pathology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
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52
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Arsenic in drinking water and bladder cancer: review of epidemiological evidence. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s1875-1121(06)09021-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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53
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Lam SH, Winata CL, Tong Y, Korzh S, Lim WS, Korzh V, Spitsbergen J, Mathavan S, Miller LD, Liu ET, Gong Z. Transcriptome kinetics of arsenic-induced adaptive response in zebrafish liver. Physiol Genomics 2006; 27:351-61. [PMID: 16882884 DOI: 10.1152/physiolgenomics.00201.2005] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Arsenic is a prominent environmental toxicant and carcinogen; however, its molecular mechanism of toxicity and carcinogenicity remains poorly understood. In this study, we performed microarray-based expression profiling on liver of zebrafish exposed to 15 parts/million (ppm) arsenic [As(V)] for 8-96 h to identify global transcriptional changes and biological networks involved in arsenic-induced adaptive responses in vivo. We found that there was an increase of transcriptional activity associated with metabolism, especially for biosyntheses, membrane transporter activities, cytoplasm, and endoplasmic reticulum in the 96 h of arsenic treatment, while transcriptional programs for proteins in catabolism, energy derivation, and stress response remained active throughout the arsenic treatment. Many differentially expressed genes encoding proteins involved in heat shock proteins, DNA damage/repair, antioxidant activity, hypoxia induction, iron homeostasis, arsenic metabolism, and ubiquitin-dependent protein degradation were identified, suggesting strongly that DNA and protein damage as a result of arsenic metabolism and oxidative stress caused major cellular injury. These findings were comparable with those reported in mammalian systems, suggesting that the zebrafish liver coupled with the available microarray technology present an excellent in vivo toxicogenomic model for investigating arsenic toxicity. We proposed an in vivo, acute arsenic-induced adaptive response model of the zebrafish liver illustrating the relevance of many transcriptional activities that provide both global and specific information of a coordinated adaptive response to arsenic in the liver.
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Affiliation(s)
- Siew Hong Lam
- Department of Biological Sciences, National University of Singapore
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54
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Wang YH, Chen YH, Wu TN, Lin YJ, Tsai HJ. A keratin 18 transgenic zebrafish Tg(k18(2.9):RFP) treated with inorganic arsenite reveals visible overproliferation of epithelial cells. Toxicol Lett 2006; 163:191-7. [PMID: 16376500 DOI: 10.1016/j.toxlet.2005.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Revised: 10/25/2005] [Accepted: 10/25/2005] [Indexed: 01/15/2023]
Abstract
Inorganic arsenic has strong human carcinogenic potential, but the availability of an animal model to study toxicity is extremely limited. Here, we used the transgenic zebrafish line Tg(k18(2.9):RFP) as an animal model to study arsenite toxicity. This line was chosen because the red fluorescent protein (RFP) is expressed in stratified epithelia (including skin), due to the RFP reporter driven by the promoter of the zebrafish keratin 18 gene. We titrated doses of inorganic arsenite for zebrafish embryos and found that arsenite exposure at 50 microM for 120 h was suitable for mimicking a long-term, chronic effect. When embryos derived from Tg(k18(2.9):RFP) adults were treated with this arsenite dose and time of exposure, abnormal phenotypes were not noticeable under the light microscope. However, arsenic keratosis was visible in the epithelial cells under the fluorescent microscope. Morphological defects became more severe with increased dose and exposure duration, suggesting that the severity of skin lesions was dose- and time-dependent. Histochemical examination of keratosis after 4',6'-diamidino-2-phenylindole hydrochloride (DAPI) staining showed that the epithelial cells overproliferated after treatment with arsenite. Therefore, this Tg(k18(2.9):RFP) zebrafish line is an excellent model for studying toxicity induced by inorganic arsenite and may have potential for studying other environmental pollutants.
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Affiliation(s)
- Yun-Hsin Wang
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan
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55
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Mourón SA, Grillo CA, Dulout FN, Golijow CD. Induction of DNA strand breaks, DNA-protein crosslinks and sister chromatid exchanges by arsenite in a human lung cell line. Toxicol In Vitro 2006; 20:279-85. [PMID: 16143491 DOI: 10.1016/j.tiv.2005.07.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Accepted: 07/21/2005] [Indexed: 02/02/2023]
Abstract
Based on in vitro studies, several modes of action for arsenic have been suggested, although the mechanisms responsible for arsenic carcinogenesis have not been well established. In our previous study a dose-dependent increment in DNA migration was detected at low doses of sodium arsenite, but at higher dose levels a reduction in the migration was observed, suggesting the induction of DNA adducts. In order to confirm this hypothesis we performed the experiments considering other parameters and modifications of the standard alkaline comet assay. Additionally, the induction of sister chromatid exchanges was evaluated. The present study showed the induction by sodium arsenite of single strand breaks and DNA-protein adducts assessed by comet assay as well as of sister chromatid exchanges in the human lung fibroblast cell line MRC-5. The standard alkaline comet assay also revealed, at the highest arsenic concentration tested, a reduction in all the considered parameters in relation to untreated cells and the other doses. On the other hand, the incubation with proteinase K induced a dose-dependent increment in DNA migration as a consequence of the release of proteins joined to the DNA. Thus, sodium arsenite was able to induce both DNA-strand breaks and protein-DNA adducts in arsenic exposed MRC-5 cells, depending on the concentrations of arsenic salts tested.
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Affiliation(s)
- Silvana Andrea Mourón
- Centro de Investigaciones en Genética Básica y Aplicada (CIGEBA), Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Calle 60 y 118 s/n, 1900 La Plata, Argentina
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56
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Bang S, Patel M, Lippincott L, Meng X. Removal of arsenic from groundwater by granular titanium dioxide adsorbent. CHEMOSPHERE 2005; 60:389-97. [PMID: 15924958 DOI: 10.1016/j.chemosphere.2004.12.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2004] [Revised: 11/30/2004] [Accepted: 12/02/2004] [Indexed: 05/02/2023]
Abstract
A novel granular titanium dioxide (TiO2) was evaluated for the removal of arsenic from groundwater. Laboratory experiments were carried out to investigate the adsorption capacity of the adsorbent and the effect of anions on arsenic removal. Batch experimental results showed that more arsenate [As(V)] was adsorbed on TiO2 than arsenite [As(III)] in US groundwater at pH 7.0. The adsorption capacities for As(V) and As(III) were 41.4 and 32.4 mgg(-1) TiO2, respectively. However, the adsorbent had a similar adsorption capacity for As(V) and As(III) (approximately 40 mgg(-1)) when simulated Bangladesh groundwater was used. Silica (20 mgl(-1)) and phosphate (5.8 mgl(-1)) had no obvious effect on the removal of As(V) and As(III) by TiO2 at neutral pH. Point-of-entry (POE) filters containing 3 l of the granular adsorbent were tested for the removal of arsenic from groundwater in central New Jersey, USA. Groundwater was continuously passed through the filters at an empty bed contact time (EBCT) of 3 min. Approximately 45,000 bed volumes of groundwater containing an average of 39 microgl(-1) of As(V) was treated by the POE filter before the effluent arsenic concentration increased to 10 microgl(-1). The total treated water volumes per weight of adsorbent were about 60,000 l per 1 kg of adsorbent. The field filtration results demonstrated that the granular TiO2 adsorbent was very effective for the removal of arsenic in groundwater.
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Affiliation(s)
- Sunbaek Bang
- Center for Environmental Systems, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA.
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57
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Lee L, Bebb G. A case of Bowen's disease and small-cell lung carcinoma: long-term consequences of chronic arsenic exposure in Chinese traditional medicine. ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:207-210. [PMID: 15687059 PMCID: PMC1277866 DOI: 10.1289/ehp.7200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2004] [Accepted: 12/20/2004] [Indexed: 05/24/2023]
Abstract
Chronic arsenic toxicity occurs primarily through inadvertent ingestion of contaminated water and food or occupational exposure, but it can also occur through medicinal ingestion. This case features a 53-year-old lifetime nonsmoker with chronic asthma treated for 10 years in childhood with Chinese traditional medicine containing arsenic. The patient was diagnosed with Bowen's disease and developed extensive-stage small-cell carcinoma of the lung 10 years and 47 years, respectively, after the onset of arsenic exposure. Although it has a long history as a medicinal agent, arsenic is a carcinogen associated with many malignancies including those of skin and lung. It is more commonly associated with non-small-cell lung cancer, but the temporal association with Bowen's disease in the absence of other chemical or occupational exposure strongly points to a causal role for arsenic in this case of small-cell lung cancer. Individuals with documented arsenic-induced Bowen's disease should be considered for more aggressive screening for long-term complications, especially the development of subsequent malignancies.
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Affiliation(s)
- Linda Lee
- University of Alberta, Faculty of Medicine, Edmonton, Alberta, Canada
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58
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Raisuddin S, Jha AN. Relative sensitivity of fish and mammalian cells to sodium arsenate and arsenite as determined by alkaline single-cell gel electrophoresis and cytokinesis-block micronucleus assay. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2004; 44:83-89. [PMID: 15199550 DOI: 10.1002/em.20027] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To protect human and ecosystem health, it is necessary to develop sensitive assays and to identify responsive cells and species (and their life stages). In this study, the relative genotoxicity of two inorganic arsenicals: trivalent sodium arsenite (As(3+)) and pentavalent sodium arsenate (As(5+)), was evaluated in two cell lines of phylogenetically different origin, using alkaline single-cell gel electrophoresis (i.e., the Comet assay) and the cytokinesis-block micronucleus (MN) assay. The cell lines were the rainbow trout gonad-2 (RTG-2) and Chinese hamster ovary-K1 (CHO-K1) lines. Following optimization and validation of both assays using reference chemicals (i.e., 1-100 microM hydrogen peroxide for the Comet assay and 1-10 mM ethylmethane sulfonate for the MN assay), cells were exposed to 1-10 microM of both arsenicals to determine the relative extent of genetic damage. The unexposed controls showed similar (background) levels of damage in both cell lines and for both assays. Treatment with the arsenicals induced concentration-dependent increases in genetic damage in the two cell lines. Arsenite was more potent than arsenate in inducing DNA strand breaks in the Comet assay; at the highest concentration (10 microM) arsenite produced similar levels of DNA damage in CHO-K1 and RTG-2 cells, while 10 microM arsenate was significantly more genotoxic in RTG-2 cells. MN induction was consistently higher in RTG-2 cells than in CHO-K1 cells, with 10 microM arsenite inducing an approximate 10-fold increase in both cell lines. MN induction also was positively correlated with DNA strand breaks for both arsenicals. Overall, the study demonstrated that the fish cells are more sensitive than the mammalian cells at environmentally realistic concentrations of both arsenicals, with arsenite being more toxic.
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Affiliation(s)
- Sheikh Raisuddin
- School of Biological Sciences, University of Plymouth, Plymouth, United Kingdom
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59
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Kligerman AD, Doerr CL, Tennant AH, Harrington-Brock K, Allen JW, Winkfield E, Poorman-Allen P, Kundu B, Funasaka K, Roop BC, Mass MJ, DeMarini DM. Methylated trivalent arsenicals as candidate ultimate genotoxic forms of arsenic: induction of chromosomal mutations but not gene mutations. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2003; 42:192-205. [PMID: 14556226 DOI: 10.1002/em.10192] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Arsenic is a prevalent human carcinogen whose mutagenicity has not been characterized fully. Exposure to either form of inorganic arsenic, As(III) or As(V), can result in the formation of at least four organic metabolites: monomethylarsonic acid, monomethylarsonous acid (MMA(III)), dimethylarsinic acid, and dimethylarsinous acid (DMA(III)). The methylated trivalent species, as well as some of the other species, have not been evaluated previously for the induction of chromosome aberrations, sister chromatid exchanges (SCE), or toxicity in cultured human peripheral blood lymphocytes; for mutagenicity in L5178Y/Tk(+/-) mouse lymphoma cells or in the Salmonella reversion assay; or for prophage-induction in Escherichia coli. Here we evaluated the arsenicals in these assays and found that MMA(III) and DMA(III) were the most potent clastogens of the six arsenicals in human lymphocytes and the most potent mutagens of the six arsenicals at the Tk(+/-) locus in mouse lymphoma cells. The dimethylated arsenicals were also spindle poisons, suggesting that they may be ultimate forms of arsenic that induce aneuploidy. Although the arsenicals were potent clastogens, none were potent SCE inducers, similar to clastogens that act via reactive oxygen species. None of the six arsenicals were gene mutagens in Salmonella TA98, TA100, or TA104; and neither MMA(III) nor DMA(III) induced prophage. Our results show that both methylated As(V) compounds were less cytotoxic and genotoxic than As(V), whereas both methylated As(III) compounds were more cytotoxic and genotoxic than As(III). Our data support the view that MMA(III) and DMA(III) are candidate ultimate genotoxic forms of arsenic and that they are clastogens and not gene mutagens. We suggest that the clastogenicity of the other arsenicals is due to their metabolism by cells to MMA(III) or DMA(III).
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Affiliation(s)
- Andrew D Kligerman
- Environmental Carcinogenesis Division, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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