1
|
Suzuki S, Gi M, Komiya M, Obikane A, Vachiraarunwong A, Fujioka M, Kakehashi A, Totsuka Y, Wanibuchi H. Evaluation of the Mechanisms Involved in the Development of Bladder Toxicity following Exposure to Occupational Bladder Cancer Causative Chemicals Using DNA Adductome Analysis. Biomolecules 2023; 14:36. [PMID: 38254636 PMCID: PMC10813811 DOI: 10.3390/biom14010036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/22/2023] [Accepted: 12/25/2023] [Indexed: 01/24/2024] Open
Abstract
Occupational exposure to aromatic amines (AAs) is an important risk factor for urinary bladder cancer. This study aimed to evaluate the toxicity of AAs and analyze the carcinogenic mechanisms in rat bladder by comprehensive analysis of DNA adducts (DNA adductome). DNA was extracted from the bladder epithelia of rats treated with AAs, including acetoacet-o-toluidine (AAOT) and o-toluidine (OTD), and adductome analysis was performed. Principal component analysis-discriminant analysis revealed that OTD and AAOT observed in urinary bladder hyperplasia could be clearly separated from the controls and other AAs. After confirming the intensity of each adduct, four adducts were screened as having characteristics of the OTD/AAOT treatment. Comparing with the in-house DNA adduct database, three of four candidates were identified as oxidative DNA adducts, including 8-OH-dG, based on mass fragmentation together with high-resolution accurate mass (HRAM) spectrometry data. Therefore, findings suggested that oxidative stress may be involved in the toxicity of rat bladder epithelium exposed to AAs. Consequently, the administration of apocynin, an inhibitor of nicotinamide adenine dinucleotide phosphate oxidase, in six-week-old rats fed with 0.6% OTD in their diet resulted in simple hyperplastic lesions in the bladder that were suppressed by apocynin. The labeling indices of Ki67, γ-H2AX, and 8-OHdG were significantly decreased in an apocynin concentration-dependent manner. These findings indicate that oxidative stress may have contributed to the development of urinary cancer induced by OTD.
Collapse
Affiliation(s)
- Shugo Suzuki
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan; (S.S.); (M.G.); (A.V.); (M.F.); (A.K.)
| | - Min Gi
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan; (S.S.); (M.G.); (A.V.); (M.F.); (A.K.)
- Department of Environmental Risk Assessment, Graduate School of Medicine, Osaka Metropolitan University, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
| | - Masami Komiya
- Laboratory of Environmental Toxicology and Carcinogenesis, School of Pharmacy, Nihon University, Chiba 274-8555, Japan;
- Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo 104-0045, Japan;
| | - Asuka Obikane
- Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo 104-0045, Japan;
- Department of Biochemistry, University of Yamanashi, Shimokato 1110, Chuo 409-3898, Japan
| | - Arpamas Vachiraarunwong
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan; (S.S.); (M.G.); (A.V.); (M.F.); (A.K.)
- Department of Environmental Risk Assessment, Graduate School of Medicine, Osaka Metropolitan University, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
| | - Masaki Fujioka
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan; (S.S.); (M.G.); (A.V.); (M.F.); (A.K.)
| | - Anna Kakehashi
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan; (S.S.); (M.G.); (A.V.); (M.F.); (A.K.)
| | - Yukari Totsuka
- Laboratory of Environmental Toxicology and Carcinogenesis, School of Pharmacy, Nihon University, Chiba 274-8555, Japan;
- Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo 104-0045, Japan;
| | - Hideki Wanibuchi
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan; (S.S.); (M.G.); (A.V.); (M.F.); (A.K.)
| |
Collapse
|
2
|
Lafranconi M, Anderson J, Budinsky R, Corey L, Forsberg N, Klapacz J, LeBaron MJ. An integrated assessment of the 1,4-dioxane cancer mode of action and threshold response in rodents. Regul Toxicol Pharmacol 2023:105428. [PMID: 37277058 DOI: 10.1016/j.yrtph.2023.105428] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/19/2023] [Accepted: 06/02/2023] [Indexed: 06/07/2023]
Abstract
1,4-Dioxane is an environmental contaminant that has been shown to cause cancer in rodents after chronic high dose exposures. We reviewed and integrated information from recently published studies to update our understanding of the cancer mode of action of 1,4-dioxane. Tumor development in rodents from exposure to high doses of 1,4-dioxane is preceded by pre-neoplastic events including increased hepatic genomic signaling activity related to mitogenesis, elevation of Cyp2E1 activity and oxidative stress leading to genotoxicity and cytotoxicity. These events are followed by regenerative repair and proliferation and eventual development of tumors. Importantly, these events occur at doses that exceed the metabolic clearance of absorbed 1,4-dioxane in rats and mice resulting in elevated systemic levels of parent 1,4-dioxane. Consistent with previous reviews, we found no evidence of direct mutagenicity from exposure to 1,4-dioxane. We also found no evidence of CAR/PXR, AhR or PPARα activation resulting from exposure to 1,4-dioxane. This integrated assessment supports a cancer mode of action that is dependent on exceeding the metabolic clearance of absorbed 1,4-dioxane, direct mitogenesis, elevation of Cyp2E1 activity and oxidative stress leading to genotoxicity and cytotoxicity followed by sustained proliferation driven by regenerative repair and progression of heritable lesions to tumor development.
Collapse
|
3
|
Ginsberg G, Chen Y, Vasiliou V. Mechanistic Considerations in 1,4-Dioxane Cancer Risk Assessment. CURRENT OPINION IN ENVIRONMENTAL SCIENCE & HEALTH 2022; 30:100407. [PMID: 37091947 PMCID: PMC10120849 DOI: 10.1016/j.coesh.2022.100407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The risk assessment of many carcinogens involves extrapolation across large exposure differences between the dose levels used in animal studies and the much lower human exposures. This is true for 1,4-dioxane which has a consistent liver carcinogenic effect in both genders of rats and mice. These data have been applied to risk assessment assuming a linear low dose extrapolation in some cases but non-linear or threshold models have been used in others. This choice hinges on our understanding of the 1,4-dioxane cancer mechanism. While 1,4-dioxane is not genotoxic in standard test batteries and has non-linear toxicokinetics, the mechanism for its carcinogenic effect remains unknown and is an active area of research. This review summarizes the possible modes of action for this chemical, data gaps and application to risk assessment. We find that the cytotoxicity/hyperplasia and metabolic saturation hypotheses do not explain the carcinogenic response and do not take into account 1,4-dioxane's induction of its own metabolism, leading to less likelihood for saturation during chronic exposure. There is evidence for other mechanisms, especially oxidative stress associated with the induction of CYP2E1 and in vivo genotoxicity that is not seen in vitro. The dose response for these effects needs further exploration compared to the time course and dose response for 1,4-dioxane-induced carcinogenesis. An additional consideration is the manner in which these 1,4-dioxane effects may augment naturally occurring and disease-related processes that contribute to the increasing rate of human liver cancer. These factors add to the rationale for using a non-threshold linear approach for extrapolating to low dose for this carcinogen, which is consistent with the default for carcinogens which do not have a clearly defined mode of action.
Collapse
Affiliation(s)
- Gary Ginsberg
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| | - Ying Chen
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| | - Vasilis Vasiliou
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| |
Collapse
|
4
|
Cui Y, Wang Y. Mass spectrometry-based DNA adductomics. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
5
|
Wang Y, Charkoftaki G, Davidson E, Orlicky DJ, Tanguay RL, Thompson DC, Vasiliou V, Chen Y. Oxidative stress, glutathione, and CYP2E1 in 1,4-dioxane liver cytotoxicity and genotoxicity: insights from animal models. CURRENT OPINION IN ENVIRONMENTAL SCIENCE & HEALTH 2022; 29:100389. [PMID: 37483863 PMCID: PMC10361651 DOI: 10.1016/j.coesh.2022.100389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
1,4-Dioxane (DX) is an emerging drinking water contaminant worldwide, which poses a threat to public health due to its demonstrated liver carcinogenicity and potential for human exposure. The lack of drinking water standards for DX is attributed to undetermined mechanisms of DX carcinogenicity. This mini-review provides a brief discussion of a series of mechanistic studies, wherein unique mouse models were exposed to DX in drinking water to elucidate redox changes associated with DX cytotoxicity and genotoxicity. The overall conclusions from these studies support a direct genotoxic effect by high dose DX and imply that oxidative stress involving CYP2E1 activation may play a causal role in DX liver genotoxicity and potentially carcinogenicity. The mechanistic data derived from these studies can serve as important references to refine the assessment of carcinogenic pathways that may be triggered at environmentally relevant low doses of DX in future animal and human studies.
Collapse
Affiliation(s)
- Yewei Wang
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| | - Georgia Charkoftaki
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| | - Emily Davidson
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
- Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT 06510, USA
| | - David J. Orlicky
- Department of Pathology, School of Medicine, University of Colorado Anschutz Medical Center, University of Colorado, Aurora, CO 80045, USA
| | - Robyn L. Tanguay
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA
| | - David C. Thompson
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| | - Vasilis Vasiliou
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| | - Ying Chen
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| |
Collapse
|
6
|
Kobets T, Smith BPC, Williams GM. Food-Borne Chemical Carcinogens and the Evidence for Human Cancer Risk. Foods 2022; 11:foods11182828. [PMID: 36140952 PMCID: PMC9497933 DOI: 10.3390/foods11182828] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
Commonly consumed foods and beverages can contain chemicals with reported carcinogenic activity in rodent models. Moreover, exposures to some of these substances have been associated with increased cancer risks in humans. Food-borne carcinogens span a range of chemical classes and can arise from natural or anthropogenic sources, as well as form endogenously. Important considerations include the mechanism(s) of action (MoA), their relevance to human biology, and the level of exposure in diet. The MoAs of carcinogens have been classified as either DNA-reactive (genotoxic), involving covalent reaction with nuclear DNA, or epigenetic, involving molecular and cellular effects other than DNA reactivity. Carcinogens are generally present in food at low levels, resulting in low daily intakes, although there are some exceptions. Carcinogens of the DNA-reactive type produce effects at lower dosages than epigenetic carcinogens. Several food-related DNA-reactive carcinogens, including aflatoxins, aristolochic acid, benzene, benzo[a]pyrene and ethylene oxide, are recognized by the International Agency for Research on Cancer (IARC) as causes of human cancer. Of the epigenetic type, the only carcinogen considered to be associated with increased cancer in humans, although not from low-level food exposure, is dioxin (TCDD). Thus, DNA-reactive carcinogens in food represent a much greater risk than epigenetic carcinogens.
Collapse
Affiliation(s)
- Tetyana Kobets
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
- Correspondence: ; Tel.: +1-914-594-3105; Fax: +1-914-594-4163
| | - Benjamin P. C. Smith
- Future Ready Food Safety Hub, Nanyang Technological University, Singapore 639798, Singapore
| | - Gary M. Williams
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
| |
Collapse
|
7
|
Turna Demir F. In vivo effects of 1,4-dioxane on genotoxic parameters and behavioral alterations in Drosophila melanogaster. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2022; 85:414-430. [PMID: 35023806 DOI: 10.1080/15287394.2022.2027832] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
1,4-Dioxane (DXN) is used as solvent in different consumer products including cosmetics, paints, surfactants, and waxes. In addition, DXN is released as an unwanted contaminating by-product as a result of some reactions including ethoxylation of alcohols, which occurs with in personal care products. Consequently, DXN pollution was detected in drinking water and is considered as an environmental problem. At present, the genotoxicity effects attributed to DXN are controversial. The present study using an in vivo model organism Drosophila melanogaster aimed to determine the toxic/genotoxic, mutagenic/recombinogenic, oxidative damage as evidenced by ROS production, phenotypic alterations as well as behavioral and developmental alterations that are closely related to neuronal functions. Data demonstrated that nontoxic DXN concentration (0.1, 0.25, 0.5, or 1%) induced mutagenic (1%) and recombinogenic (0.1, 0.25, or 0.5%) effects in wing spot test and genotoxicity in hemocytes using comet assay. The nontoxic concentrations of DXN (0.1, 0.25, 0.5, or 1%) significantly increased oxidative stress, climbing behavior, thermal sensivity and abnormal phenotypic alterations. Our findings show that in contrast to in vitro exposure, DXN using an in vivo model Drosophila melanogaster this compound exerts toxic and genotoxic effects. Data suggest that additional studies using other in vivo models are thus warranted.
Collapse
Affiliation(s)
- Fatma Turna Demir
- Vocational School of Health Services, Department of Medical Services and Techniques, Medical Laboratory Techniques Programme, Antalya Bilim University, Antalya, Turkey
| |
Collapse
|
8
|
Chen Y, Wang Y, Charkoftaki G, Orlicky DJ, Davidson E, Wan F, Ginsberg G, Thompson DC, Vasiliou V. Oxidative stress and genotoxicity in 1,4-dioxane liver toxicity as evidenced in a mouse model of glutathione deficiency. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150703. [PMID: 34600989 PMCID: PMC8633123 DOI: 10.1016/j.scitotenv.2021.150703] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 09/27/2021] [Accepted: 09/27/2021] [Indexed: 05/19/2023]
Abstract
1,4-Dioxane (DX) is a synthetic chemical used as a stabilizer for industrial solvents. Recent occurrence data show widespread and significant contamination of drinking water with DX in the US. DX is classified by the International Agency for Research on Cancer as a group 2B carcinogen with the primary target organ being the liver in animal studies. Despite the exposure and cancer risk, US EPA has not established a drinking water Maximum Contaminant Level (MCL) for DX and a wide range of drinking water targets have been established across the US and by Health Canada. The DX carcinogenic mechanism remains unknown; this information gap contributes to the varied approaches to its regulation. Our recent mice study indicated alterations in oxidative stress response accompanying DNA damage as an early change by high dose DX (5000 ppm) in drinking water. Herein, we report a follow-up study, in which we used glutathione (GSH)-deficient glutamate-cysteine ligase modifier subunit (Gclm)-null mice to investigate the role of redox homeostasis in DX-induced liver cytotoxicity and genotoxicity. Gclm-null and wild-type mice were exposed to DX for one week (1000 mg/kg/day by oral gavage) or three months (5000 ppm in drinking water). Subchronic exposure of high dose DX caused mild liver cytotoxicity. DX induced assorted molecular changes in the liver including: (i) a compensatory nuclear factor erythroid 2-related factor 2 (NRF2) anti-oxidative response at the early stage (one week), (ii) progressive CYP2E1 induction, (iii) development of oxidative stress, as evidenced by persistent NRF2 induction, oxidation of GSH pool, and accumulation of the lipid peroxidation by-product 4-hydroxynonenal, and (iv) elevations in oxidative DNA damage and DNA repair response. These DX-elicited changes were exaggerated in GSH-deficient mice. Collectively, the current study provides additional evidence linking redox dysregulation to DX liver genotoxicity, implying oxidative stress as a candidate mechanism of DX liver carcinogenicity.
Collapse
Affiliation(s)
- Ying Chen
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA.
| | - Yewei Wang
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| | - Georgia Charkoftaki
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| | - David J Orlicky
- Department of Pathology, School of Medicine, University of Colorado Anschutz Medical Center, University of Colorado, Aurora, CO 80045, USA
| | - Emily Davidson
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA; Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT 06510, USA
| | - Fengjie Wan
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| | - Gary Ginsberg
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA
| | - David C Thompson
- Department of Clinical Pharmacy, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of Colorado, Aurora, CO 80045, USA
| | - Vasilis Vasiliou
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT 06510, USA.
| |
Collapse
|
9
|
Sengul A, Yengin C, Egrilmez S, Kilinc E. OUP accepted manuscript. J Chromatogr Sci 2022; 61:375-392. [PMID: 35441225 DOI: 10.1093/chromsci/bmac031] [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: 09/23/2021] [Indexed: 11/13/2022]
Abstract
HPLC-PDA, LC-MS/MS methods were developed for simultaneous determination of a group of oxidative stress biomarkers (OSBs); 2dA, 2dC, 2dU, 3NLT, 5HMU and 8OHdG in 10 simulated artificial body fluids. O-phosphoric acid and methanol composed mobile phases A and B for gradient elution in HPLC-PDA using ODS-2 column. Linearity obtained for 1.0×10-6-1.0×10-4M range. LODs were 1.73×10-6, 1.19×10-6, 2.59×10-6, 1.40×10-6, 2.21×10-6 and 4.07×10-6M for 2dU, 8OHdG, 2dA, 2dC, 5HMU and 3NLT, respectively. LOQs were 5.29×10-6, 4.02×10-6, 6.82×10-6, 4.02×10-6, 6.82×10-6 and 9.92×10-6M. About 10 mM aqueous ammonium acetate solution and methanol containing 0.1% (v/v) formic acid composed mobile phases A and B for gradient elution in LC-MS/MS. Linearity obtained for 1.0×10-8-1.0×10-6M range. LODs were 2.88×10-10, 1.01×10-8, 3.38×10-9, 1.36×10-7, 1.81×10-7 and 1.40×10-8M for 2dU, 8OHdG, 2dA, 2dC, 5HMU and 3NLT, respectively. LOQs were 9.37×10-10, 3.22×10-8, 1.91×10-8, 4.53×10-7, 5.90×10-7 and 2.18×10-8M. Both methods were validated using ICH Q2(R1) guideline. Specificity, linearity, range, accuracy, precision, reproducibility, LOD, LOQ and recovery were achieved. Chemometric analysis was performed on raw PDA and MS data to check their significance for discrimination of OSBs. Sets of single and triple quadrupole fragmentations were evaluated for principle component analysis. Chosen number of PCs successfully distinguished OSBs of interest.
Collapse
Affiliation(s)
- Ayse Sengul
- Department of Analytical Chemistry, Faculty of Pharmacy, Ege University, , Bornova, TR-35100, Izmir, Türkiye
| | - Cigdem Yengin
- Department of Pharmaceutical Chemistry, Bornova, TR-35100, Izmir, Türkiye
| | - Sait Egrilmez
- Faculty of Medicine, Department of Ophthalmology, Bornova, TR-35100, Izmir, Türkiye
| | - Emrah Kilinc
- Department of Analytical Chemistry, Faculty of Pharmacy, Ege University, , Bornova, TR-35100, Izmir, Türkiye
| |
Collapse
|
10
|
Chen R, Miao Y, Liu Y, Zhang L, Zhong M, Adams JM, Dong Y, Mahendra S. Identification of novel 1,4-dioxane degraders and related genes from activated sludge by taxonomic and functional gene sequence analysis. JOURNAL OF HAZARDOUS MATERIALS 2021; 412:125157. [PMID: 33540262 DOI: 10.1016/j.jhazmat.2021.125157] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
This study used integrated omics technologies to investigate the potential novel pathways and enzymes for 1,4-dioxane degradation by a consortium enriched from activated sludge of a domestic wastewater treatment plant. An unclassified genus belonging to Xanthobacteraceae increased significantly after magnetic nanoparticle-mediated isolation for 1,4-dioxane degraders. Species with relatively higher abundance (> 0.3%) were identified to present high metabolic activities in the biodegradation process through shotgun sequencing. The functional gene investigations revealed that Xanthobacter sp. 91, Xanthobacter sp. 126, and a Rhizobiales strain carried novel 1,4-dioxane-hydroxylating monooxygenase genes. Xanthobacter sp. 126 contained the genes coding for glycolate oxidase, which was the main enzyme responsible for utilization of 1,4-dioxane intermediates through the TCA cycle, and further proven by the specific glycolate oxidase inhibitor, α-hydroxy-2-pyridinemethanesulfonic acid. An expanded and detailed degradation pathway of 1,4-dioxane was proposed on the basis of the three major intermediates (2-hydroxy-1,4-dioxane, ethylene glycol, and oxalic acid) confirmed by metabolomics. These findings of microbial community and function as well as the novel pathway will be valuable in predicting natural attenuation or reconstruction of a bacterial consortium for enhanced remediation of 1,4-dioxane-contaminated sites as well as wastewater treatment.
Collapse
Affiliation(s)
- Ruihuan Chen
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100000, China; College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Yu Miao
- Civil and Environmental Engineering, University of California, Los Angeles, CA 90095, USA
| | - Yun Liu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100000, China; National Engineering Laboratory of Site Remediation Technologies, Beijing 100015, China.
| | - Lan Zhang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100000, China
| | - Ming Zhong
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100000, China
| | | | - Yuanhua Dong
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100000, China
| | - Shaily Mahendra
- Civil and Environmental Engineering, University of California, Los Angeles, CA 90095, USA
| |
Collapse
|
11
|
Totsuka Y, Watanabe M, Lin Y. New horizons of DNA adductome for exploring environmental causes of cancer. Cancer Sci 2021; 112:7-15. [PMID: 32978845 PMCID: PMC7780056 DOI: 10.1111/cas.14666] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/08/2020] [Accepted: 09/17/2020] [Indexed: 12/31/2022] Open
Abstract
Chemical carcinogenesis is focused on the formation of DNA adducts, a form of DNA damage caused by covalent binding of a chemical moiety to DNA. The detection of carcinogen-DNA adducts in human tissues, along with demonstration of mutagenicity/carcinogenicity in experimental systems, and validation of adducts as biomarkers of environmental exposure and indicators of cancer risk in molecular epidemiological studies suggests a pivotal role of DNA adducts in cancer development. However, accurate measurement of DNA adducts in varied biological samples is challenging. Advances in mass spectrometry have prompted the development of DNA adductome analysis, an emerging method that simultaneously screens for multiple DNA adducts and provides relevant structural information. In this review, we summarize the basic principle and applications of DNA adductome analysis that would contribute to the elucidation of the environmental causes of cancer. Based on parallel developments in several fields, including next-generation sequencing, we describe a new approach used to explore cancer etiology, which integrates analyses of DNA adductome data and mutational signatures derived from whole-genome/exome sequencing.
Collapse
Affiliation(s)
- Yukari Totsuka
- Department of Cancer Model DevelopmentNational Cancer Center Research InstituteTokyoJapan
| | | | - Yingsong Lin
- Department of Public HealthAichi Medical University School of MedicineNagakuteJapan
| |
Collapse
|
12
|
A 90-day drinking water study in mice to characterize early events in the cancer mode of action of 1,4-dioxane. Regul Toxicol Pharmacol 2020; 119:104819. [PMID: 33189748 DOI: 10.1016/j.yrtph.2020.104819] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 09/23/2020] [Accepted: 11/03/2020] [Indexed: 01/01/2023]
Abstract
Studies demonstrate that with sufficient dose and duration, 1,4-dioxane (1,4-DX) induces liver tumors in laboratory rodent models. The available evidence aligns with a threshold-dependent, tumor promotion mode of action (MOA). The MOA and key events (KE) in rats are well developed but less so in the mouse. Therefore, we conducted a 90-day drinking water study in female mice to evaluate early KE at 7, 28, and 90 days. Female B6D2F1/Crl mice consumed drinking water containing 0, 40, 200, 600, 2000 or 6000 ppm 1,4-DX. 1,4-DX was detected in blood at 90-days of exposure to 6000 ppm, but not in the other exposure groups, indicating a metabolic clearance threshold between 2000 and 6000. Early events identified in this study include glycogen-like vacuolization, centrilobular hypertrophy, centrilobular GST-P staining, apoptosis, and pan-lobular increase in cell proliferation observed after 90-days of exposure to 6000 ppm 1,4-DX. There was minimal evidence of hepatotoxicity over the duration of this study. These findings demonstrate a previously unreported direct mitogenic response following exposures exceeding the metabolic clearance threshold of 1,4-DX. Collectively, the information generated in this study supports a threshold MOA for the development of liver tumors in mice after exposure to 1,4-DX.
Collapse
|