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Heck JE, He D, Wing SE, Ritz B, Carey CD, Yang J, Stram DO, Le Marchand L, Park SL, Cheng I, Wu AH. Exposure to outdoor ambient air toxics and risk of breast cancer: The multiethnic cohort. Int J Hyg Environ Health 2024; 259:114362. [PMID: 38574449 DOI: 10.1016/j.ijheh.2024.114362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 03/01/2024] [Accepted: 03/24/2024] [Indexed: 04/06/2024]
Abstract
BACKGROUND A growing literature has reported associations between traffic-related air pollution and breast cancer, however there are fewer investigations into specific ambient agents and any putative risk of breast cancer development, particularly studies occurring in populations residing in higher pollution areas such as Los Angeles. OBJECTIVES To estimate breast cancer risks related to ambient air toxics exposure at residential addresses. METHODS We examined the relationships between ambient air toxics and breast cancer risk in the Multiethnic Cohort among 48,665 California female participants followed for cancer from 2003 through 2013. We obtained exposure data on chemicals acting as endocrine disruptors or mammary gland carcinogens from the National-Scale Air Toxics Assessment. Cox proportional hazards models were used to estimate breast cancer risk per one interquartile range (IQR) increase in air toxics exposure lagged by 5-years. Stratified analyses were conducted by race, ethnicity, and hormone receptor types. RESULTS Among all women, increased risks of invasive breast cancer were observed with toxicants related to industries [1,1,2,2-tetrachloroethane (hazard ratio [HR] = 4.22, 95% confidence interval [95% CI] 3.18-5.60), ethylene dichloride (HR = 2.81, 95% CI 2.20-3.59), and vinyl chloride (HR = 2.27, 95% CI 1.81, 2.85); these 3 agents were correlated (r2 = 0.45-0.77)]. Agents related to gasoline production or combustion were related to increased breast cancer risk [benzene (HR = 1.32, 95% CI 1.24, 1.41), ethylbenzene (HR = 1.20, 95% CI 1.13-1.28), toluene (HR = 1.29, 95% CI 1.20-1.38), naphthalene (HR = 1.11, 95% CI 1.02-2.22), acrolein (HR = 2.26, 95% CI 1.92, 2.65)]. Higher hazard ratios were observed in African Americans and Whites compared to other racial and ethnic groups (p-heterogeneity <0.05 for traffic-related air toxics, acrolein, and vinyl acetate). CONCLUSIONS Our findings suggest that specific toxic air pollutants may be associated with increase breast cancer risk.
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Affiliation(s)
- Julia E Heck
- Department of Epidemiology, School of Public Health, University of California, Los Angeles, CA, USA; College of Health and Public Service, University of North Texas, Denton, TX, USA; Center for Racial and Ethnic Equity in Health and Society, University of North Texas, Denton, TX, USA.
| | - Di He
- Department of Epidemiology, School of Public Health, University of California, Los Angeles, CA, USA
| | - Sam E Wing
- Department of Epidemiology, School of Public Health, University of California, Los Angeles, CA, USA
| | - Beate Ritz
- Department of Epidemiology, School of Public Health, University of California, Los Angeles, CA, USA
| | - Chandra D Carey
- College of Health and Public Service, University of North Texas, Denton, TX, USA; Center for Racial and Ethnic Equity in Health and Society, University of North Texas, Denton, TX, USA
| | - Juan Yang
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA
| | - Daniel O Stram
- Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Loïc Le Marchand
- Epidemiology Section, Population Sciences in the Pacific Program, University of Hawaii Cancer Center, Honolulu, HI, USA
| | - Sungshim Lani Park
- Epidemiology Section, Population Sciences in the Pacific Program, University of Hawaii Cancer Center, Honolulu, HI, USA
| | - Iona Cheng
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA; University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, CA, USA
| | - Anna H Wu
- Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Connell ML, Wu CC, Blount JR, Haimbaugh A, Kintzele EK, Banerjee D, Baker BB, Baker TR. Adult-Onset Transcriptomic Effects of Developmental Exposure to Benzene in Zebrafish ( Danio rerio): Evaluating a Volatile Organic Compound of Concern. Int J Mol Sci 2023; 24:16212. [PMID: 38003401 PMCID: PMC10671089 DOI: 10.3390/ijms242216212] [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: 09/23/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Urban environments are afflicted by mixtures of anthropogenic volatile organic compounds (VOCs). VOC sources that drive human exposure include vehicle exhaust, industrial emissions, and oil spillage. The highly volatile VOC benzene has been linked to adverse health outcomes. However, few studies have focused on the later-in-life effects of low-level benzene exposure during the susceptible window of early development. Transcriptomic responses during embryogenesis have potential long-term consequences at levels equal to or lower than 1 ppm, therefore justifying the analysis of adult zebrafish that were exposed during early development. Previously, we identified transcriptomic alteration following controlled VOC exposures to 0.1 or 1 ppm benzene during the first five days of embryogenesis using a zebrafish model. In this study, we evaluated the adult-onset transcriptomic responses to this low-level benzene embryogenesis exposure (n = 20/treatment). We identified key genes, including col1a2 and evi5b, that were differentially expressed in adult zebrafish in both concentrations. Some DEGs overlapped at the larval and adult stages, specifically nfkbiaa, mecr, and reep1. The observed transcriptomic results suggest dose- and sex-dependent changes, with the highest impact of benzene exposure to be on cancer outcomes, endocrine system disorders, reproductive success, neurodevelopment, neurological disease, and associated pathways. Due to molecular pathways being highly conserved between zebrafish and mammals, developmentally exposed adult zebrafish transcriptomics is an important endpoint for providing insight into the long term-effects of VOCs on human health and disease.
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Affiliation(s)
- Mackenzie L. Connell
- Department of Global and Environmental Health, University of Florida, Gainesville, FL 32610, USA; (M.L.C.); (E.K.K.); (D.B.)
| | - Chia-Chen Wu
- Institute of Environmental Engineering, National Yang Ming Chiao Tung University, Hsinchu City 300093, Taiwan;
| | - Jessica R. Blount
- Institute of Environmental Health Sciences, Integrative Biosciences Center, Wayne State University, Detroit, MI 48202, USA; (J.R.B.); (A.H.)
| | - Alex Haimbaugh
- Institute of Environmental Health Sciences, Integrative Biosciences Center, Wayne State University, Detroit, MI 48202, USA; (J.R.B.); (A.H.)
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Emily K. Kintzele
- Department of Global and Environmental Health, University of Florida, Gainesville, FL 32610, USA; (M.L.C.); (E.K.K.); (D.B.)
| | - Dayita Banerjee
- Department of Global and Environmental Health, University of Florida, Gainesville, FL 32610, USA; (M.L.C.); (E.K.K.); (D.B.)
| | - Bridget B. Baker
- IFAS Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA;
| | - Tracie R. Baker
- Department of Global and Environmental Health, University of Florida, Gainesville, FL 32610, USA; (M.L.C.); (E.K.K.); (D.B.)
- Institute of Environmental Health Sciences, Integrative Biosciences Center, Wayne State University, Detroit, MI 48202, USA; (J.R.B.); (A.H.)
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
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Westra S, Goldberg MS, Labrèche F, Baumgartner J, Ho V. The association between the incidence of postmenopausal breast cancer and occupational exposure to selected organic solvents, Montreal, Canada, 2008-2011. Am J Ind Med 2023; 66:911-927. [PMID: 37565624 DOI: 10.1002/ajim.23525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 07/17/2023] [Accepted: 07/27/2023] [Indexed: 08/12/2023]
Abstract
BACKGROUND Breast cancer is the most diagnosed cancer among women and recognized risk factors explain 25%-47% of cases. Organic solvents are used widely in the workplace and exposure may increase the risk of developing breast cancer, yet there are insufficient data to confirm this hypothesis. We sought to determine whether past occupational exposures to selected organic solvents were associated with the incidence of invasive breast cancer in postmenopausal women in Montréal, Canada. METHODS From a population-based case-control study (2008-2011), using in-depth interviews we elicited information on risk factors and lifetime occupational histories. Industrial hygienists and chemists translated job descriptions into specific chemical and physical exposures. We assessed 11 individual solvents and four solvent groups. Unconditional logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for metrics of past exposures to selected solvents. Exposure metrics included any previous exposure, average frequency in hours per week, duration in years, and average cumulative concentration weighted by hours per workweek exposed. RESULTS We enrolled 695 cases and 608 controls. We found increased ORs for average cumulative concentration of exposure to mononuclear aromatic hydrocarbons (OR: 1.52, 95% CI: 1.04, 2.28), chlorinated alkanes (OR: 2.42, 95% CI: 1.23, 5.68), toluene (OR: 1.59, 95% CI: 1.02, 2.59), and a group of organic solvents with reactive metabolites (OR: 1.53, 95% CI: 1.08, 2.24). Positive associations were found across all exposure metrics and were higher among women with estrogen-positive/progesterone-negative tumors. CONCLUSION Our findings suggest occupational exposure to certain organic solvents may increase the risk of incident postmenopausal breast cancer.
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Affiliation(s)
- Sydney Westra
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, Québec, Canada
| | - Mark S Goldberg
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, Québec, Canada
- Department of Medicine, McGill University, Montréal, Québec, Canada
| | - France Labrèche
- Department of Environmental and Occupational Health, School of Public Health and Centre de recherche en santé publique (CReSP), University of Montréal and CIUSSS Centre-Sud, Montréal, Québec, Canada
- Institut de recherche Robert-Sauvé en santé et en sécurité du travail, Montréal, Québec, Canada
| | - Jill Baumgartner
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, Québec, Canada
- Department of Ethics, Equity and Policy, McGill University, Montréal, Québec, Canada
| | - Vikki Ho
- Health Innovation and Evaluation Hub Université de Montréal Hospital Research Centre (CRCHUM), Montréal, Québec, Canada
- Department of Social and Preventive Medicine, Université de Montréal School of Public Health (ESPUM), Montréal, Québec, Canada
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Zhang L, Sun P, Sun D, Zhou Y, Han L, Zhang H, Zhu B, Wang B. Occupational health risk assessment of the benzene exposure industries: a comprehensive scoring method through 4 health risk assessment models. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:84300-84311. [PMID: 35780272 DOI: 10.1007/s11356-022-21275-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Benzene is one of the most common occupational hazards in the working environment which was in the list of group 1 carcinogens. This study applied four occupational health risk assessment models: EPA model; MOM model of Singapore; the International Council on Mining and Metals (ICMM) model, and the Technical guide WS/T 777-2021 of China. The models assessed both non-carcinogenic and carcinogenic effects of benzene for 1629 employees in 50 factories in Jiangsu Province (China) who were exposed to benzene in the working environment and analysis the risk between industries by principal component analysis (PCA) method. The highest occupational health hazard of benzene among the five industries is petroleum processing industry, then followed by chemical products manufacturing industry, special equipment manufacturing industry, wood processing and products industry, and at last the pharmaceutical manufacturing industry. The population of abnormal routine blood parameters in the subjects was mostly in the "wood products industry" group, and the concentration of benzene in "wood products industry" group is the lowest in 5 groups. The industries with low exposure concentration have higher blood abnormality rates; this may be caused by the fact that blood damage is more secretive under low occupational health risk.
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Affiliation(s)
- Ludi Zhang
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing , 210009, Jiangsu, China
- Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, 210000, Jiangsu, China
| | - Peng Sun
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing , 210009, Jiangsu, China
- Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, 210000, Jiangsu, China
| | - Dawei Sun
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing , 210009, Jiangsu, China
| | - Yanhua Zhou
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing , 210009, Jiangsu, China
| | - Lei Han
- Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, 210000, Jiangsu, China
| | - Hengdong Zhang
- Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, 210000, Jiangsu, China
| | - Baoli Zhu
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing , 210009, Jiangsu, China.
- Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, 210000, Jiangsu, China.
- Center for Global Health, Nanjing Medical University, Nanjing, China.
- Jiangsu Province Engineering Research Center of Public Health Emergency, Jiangsu, China.
| | - Boshen Wang
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing , 210009, Jiangsu, China.
- Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, 210000, Jiangsu, China.
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Breast cancer incidence in a national cohort of female workers exposed to special health hazards in Taiwan: a retrospective case-cohort study of ~ 300,000 occupational records spanning 20 years. Int Arch Occup Environ Health 2022; 95:1979-1993. [PMID: 35771278 DOI: 10.1007/s00420-022-01897-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 05/31/2022] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Breast cancer is the most common cancer among women worldwide. In Taiwan, workers exposed to any of 31 hazardous chemicals or carcinogens in the work environment are designated as especially exposed workers (EEWs) by Taiwan's Ministry of Labor. We assessed the risk of breast cancer in this nationwide female EEW cohort. METHODS We conducted a nationwide retrospective study of 4,774,295 workers combining data collected from Taiwan's Ministry of Labor's EEW database between 1997 and 2018 and Taiwan's Cancer Registry between 1997 and 2016. Standardized incidence ratios (SIRs) for women exposed to different hazards and breast cancer incidence rate ratios (IRRs) were calculated by Poisson regression, adjusting for age and duration of exposure. RESULTS 3248 female workers with breast cancer and 331,967 without breast cancer were included. The SIRs and adjusted IRRs were 1.27 (95% CI 1.18-1.35) and 1.31 (95% CI 1.21-1.42) for lead, 1.74 (95% CI 1.23-2.24) and 1.52 (95% CI 1.13-2.04) for 1,1,2,2-tetrachloroethane, 1.47 (95% CI 1.12-1.82) and 1.42 (95% CI 1.12-1.81) for trichloroethylene/tetrachloroethylene), 1.40 (95% CI 1.23-1.57) and 1.38 (95% CI 1.22-1.57) for benzene, and 2.07 (95% CI 1.06-3.09) and 1.80 (95% CI 1.10-2.94) for asbestos. The results remained similar when factoring in a 2- or 5-year latency period. CONCLUSION This study found possible correlations between occupational exposure to lead, chlorinated solvents (such as 1,1,2,2-tetrachloroethane, trichloroethylene, and tetrachloroethylene), benzene, and asbestos with breast cancer risk among female EEW, suggesting a need for regular screening for breast cancer for employees exposed to these special workplace hazards.
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Mueller S, Dennison G, Liu S. An Assessment on Ethanol-Blended Gasoline/Diesel Fuels on Cancer Risk and Mortality. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:6930. [PMID: 34203568 PMCID: PMC8297295 DOI: 10.3390/ijerph18136930] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/28/2021] [Accepted: 06/13/2021] [Indexed: 12/23/2022]
Abstract
Although cancer is traditionally considered a genetic disease, the epigenetic abnormalities, including DNA hypermethylation, histone deacetylation, and/or microRNA dysregulation, have been demonstrated as a hallmark of cancer. Compared with gene mutations, aberrant epigenetic changes occur more frequently, and cellular epigenome is more susceptible to change by environmental factors. Excess cancer risks are positively associated with exposure to occupational and environmental chemical carcinogens, including those from gasoline combustion exhausted in vehicles. Of note, previous studies proposed particulate matter index (PMI) as a measure for gasoline sooting tendency, and showed that, compared with the other molecules in gasoline, 1,2,4-Trimethylbenzene, 2-methylnaphthalene and toluene significantly contribute to PMI of the gasoline blends. Mechanistically, both epigenome and genome are important in carcinogenicity, and the genotoxicity of chemical agents has been thoroughly studied. However, less effort has been put into studying the epigenotoxicity. Moreover, as the blending of ethanol into gasoline substitutes for carcinogens, like benzene, toluene, xylene, butadiene, and polycyclic aromatic hydrocarbons, etc., a reduction of secondary aromatics has been achieved in the atmosphere. This may lead to diminished cancer initiation and progression through altered cellular epigenetic landscape. The present review summarizes the most important findings in the literature on the association between exposures to carcinogens from gasoline combustion, cancer epigenetics and the potential epigenetic impacts of biofuels.
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Affiliation(s)
- Steffen Mueller
- Energy Resources Center, The University of Illinois at Chicago, Chicago, IL 60607, USA;
| | - Gail Dennison
- The Hormel Institute, University of Minnesota, Austin, MN 55912, USA;
| | - Shujun Liu
- The Hormel Institute, University of Minnesota, Austin, MN 55912, USA;
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Epigenetic Effects of Benzene in Hematologic Neoplasms: The Altered Gene Expression. Cancers (Basel) 2021; 13:cancers13102392. [PMID: 34069279 PMCID: PMC8156840 DOI: 10.3390/cancers13102392] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/06/2021] [Accepted: 05/11/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Benzene is produced by diverse petroleum transformation processes and it is widely employed in industry despite its oncogenic effects. In fact, occupational exposure to benzene may cause hematopoietic malignancy. The leukemogenic action of benzene is particularly complex. Possible processes of onset of hematological malignancies have been recognized as a genotoxic action and the provocation of immunosuppression. However, benzene can induce modifications that do not involve alterations in the DNA sequence, the so-called epigenetics changes. Acquired epigenetic modification may also induce leukemogenesis, as benzene may alter nuclear receptors, and cause changes at the protein level, thereby modifying the function of regulatory proteins, including oncoproteins and tumor suppressor proteins. Abstract Benzene carcinogenic ability has been reported, and chronic exposure to benzene can be one of the risk elements for solid cancers and hematological neoplasms. Benzene is acknowledged as a myelotoxin, and it is able to augment the risk for the onset of acute myeloid leukemia, myelodysplastic syndromes, aplastic anemia, and lymphomas. Possible mechanisms of benzene initiation of hematological tumors have been identified, as a genotoxic effect, an action on oxidative stress and inflammation and the provocation of immunosuppression. However, it is becoming evident that genetic alterations and the other causes are insufficient to fully justify several phenomena that influence the onset of hematologic malignancies. Acquired epigenetic alterations may participate with benzene leukemogenesis, as benzene may affect nuclear receptors, and provoke post-translational alterations at the protein level, thereby touching the function of regulatory proteins, comprising oncoproteins and tumor suppressor proteins. DNA hypomethylation correlates with stimulation of oncogenes, while the hypermethylation of CpG islands in promoter regions of specific tumor suppressor genes inhibits their transcription and stimulates the onset of tumors. The discovery of the systems of epigenetic induction of benzene-caused hematological tumors has allowed the possibility to operate with pharmacological interventions able of stopping or overturning the negative effects of benzene.
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Aravind M, Kappen J, Varalakshmi P, John SA, Ashokkumar B. Bioengineered Graphene Oxide Microcomposites Containing Metabolically Versatile Paracoccus sp. MKU1 for Enhanced Catechol Degradation. ACS OMEGA 2020; 5:16752-16761. [PMID: 32685843 PMCID: PMC7364705 DOI: 10.1021/acsomega.0c01693] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/10/2020] [Indexed: 06/11/2023]
Abstract
Paracoccus sp. MKU1, a metabolically versatile bacterium that encompasses diverse metabolic pathways in its genome for the degradation of aromatic compounds, was investigated for catechol bioremediation here for the first time to our knowledge. Paracoccus sp. MKU1 degraded catechol at an optimal pH of 7.5 and a temperature of 37 °C, wherein 100 mg/L catechol was completely mineralized in 96 h but required 192 h for complete mineralization of 500 mg/L catechol. While investigating the molecular mechanisms of its degradation potential, it was unveiled that Paracoccus sp. MKU1 employed both the ortho and meta pathways by inducing the expression of catechol 1,2-dioxygenase (C12O) and catechol 2,3-dioxygenase (C23O), respectively. C23O expression at transcriptional levels was significantly more abundant than C12O, which indicated that catechol degradation was primarily mediated by extradiol cleavage by MKU1. Furthermore, poly(MAA-co-BMA)-GO (PGO) microcomposites containing Paracoccus sp. MKU1 were synthesized, which degraded catechol (100 mg/L) completely within 48 h with excellent recycling performance for three cycles. Thus, PGO@Paracoccus microcomposites proved to be efficient in catechol degradation at not only faster rates but also with excellent recycling performances than free cells. These findings accomplish that Paracoccus sp. MKU1 could serve as a potential tool for bioremediation of catechol-polluted industrial wastewater and soil.
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Affiliation(s)
- Manikka
Kubendran Aravind
- Department
of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India
| | - Jincymol Kappen
- Centre
for Nanoscience and Nanotechnology, Department of Chemistry, Gandhigram Rural Institute, Gandhigram 624302, Tamil Nadu, India
| | - Perumal Varalakshmi
- Department
of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India
| | - Swamidoss Abraham John
- Centre
for Nanoscience and Nanotechnology, Department of Chemistry, Gandhigram Rural Institute, Gandhigram 624302, Tamil Nadu, India
| | - Balasubramaniem Ashokkumar
- Department
of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India
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Hiatt RA, Engmann NJ, Balke K, Rehkopf DH. A Complex Systems Model of Breast Cancer Etiology: The Paradigm II Conceptual Model. Cancer Epidemiol Biomarkers Prev 2020; 29:1720-1730. [PMID: 32641370 DOI: 10.1158/1055-9965.epi-20-0016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/09/2020] [Accepted: 06/04/2020] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The etiology of breast cancer is a complex system of interacting factors from multiple domains. New knowledge about breast cancer etiology continues to be produced by the research community, and the communication of this knowledge to other researchers, practitioners, decision makers, and the public is a challenge. METHODS We updated the previously published Paradigm model (PMID: 25017248) to create a framework that describes breast cancer etiology in four overlapping domains of biologic, behavioral, environmental, and social determinants. This new Paradigm II conceptual model was part of a larger modeling effort that included input from multiple experts in fields from genetics to sociology, taking a team and transdisciplinary approach to the common problem of describing breast cancer etiology for the population of California women in 2010. Recent literature was reviewed with an emphasis on systematic reviews when available and larger epidemiologic studies when they were not. Environmental chemicals with strong animal data on etiology were also included. RESULTS The resulting model illustrates factors with their strength of association and the quality of the available data. The published evidence supporting each relationship is made available herein, and also in an online dynamic model that allows for manipulation of individual factors leading to breast cancer (https://cbcrp.org/causes/). CONCLUSIONS The Paradigm II model illustrates known etiologic factors in breast cancer, as well as gaps in knowledge and areas where better quality data are needed. IMPACT The Paradigm II model can be a stimulus for further research and for better understanding of breast cancer etiology.
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Affiliation(s)
- Robert A Hiatt
- Department of Epidemiology & Biostatistics, University of California San Francisco, San Francisco, California. .,Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California
| | | | - Kaya Balke
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California
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Rodríguez-Salazar J, Almeida-Juarez AG, Ornelas-Ocampo K, Millán-López S, Raga-Carbajal E, Rodríguez-Mejía JL, Muriel-Millán LF, Godoy-Lozano EE, Rivera-Gómez N, Rudiño-Piñera E, Pardo-López L. Characterization of a Novel Functional Trimeric Catechol 1,2-Dioxygenase From a Pseudomonas stutzeri Isolated From the Gulf of Mexico. Front Microbiol 2020; 11:1100. [PMID: 32582076 PMCID: PMC7287156 DOI: 10.3389/fmicb.2020.01100] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/04/2020] [Indexed: 12/17/2022] Open
Abstract
Catechol 1,2 dioxygenases (C12DOs) have been studied for its ability to cleavage the benzene ring of catechol, the main intermediate in the degradation of aromatic compounds derived from aerobic degradation of hydrocarbons. Here we report the genome sequence of the marine bacterium Pseudomonas stutzeri GOM2, isolated from the southwestern Gulf of Mexico, and the biochemical characterization of its C12DO (PsC12DO). The catA gene, encoding PsC12DO of 312 amino acid residues, was cloned and expressed in Escherichia coli. Many C12DOs have been described as dimeric enzymes including those present in Pseudomonas species. The purified PsC12DO enzyme was found as an active trimer, with a molecular mass of 107 kDa. Increasing NaCl concentration in the enzyme reaction gradually reduced activity; in high salt concentrations (0.7 M NaCl) quaternary structural analysis determined that the enzyme changes to a dimeric arrangement and causes a 51% decrease in specific activity on catechol substrate. In comparison with other C12DOs, our enzyme showed a broad range of action for PsC12DO in solutions with pH values ranging from neutral to alkaline (70%). The enzyme is still active after incubation at 50°C for 30 min and in low temperatures to long term storage after 6 weeks at 4°C (61%). EDTA or Ca2+ inhibitors cause no drastic changes on residual activity; nevertheless, the activity of the enzyme was affected by metal ions Fe3+, Zn2+ and was completely inhibited by Hg2+. Under optimal conditions the k cat and K m values were 16.13 s-1 and 13.2 μM, respectively. To our knowledge, this is the first report describing the characterization of a marine C12DOs from P. stutzeri isolated from the Gulf of Mexico that is active in a trimeric state. We consider that our enzyme has important features to be used in environments in presence of EDTA, metals and salinity conditions.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Liliana Pardo-López
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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Affiliation(s)
- Robert A. Hiatt
- Department of Epidemiology and Biostatistics and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, California 94158, USA
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Adverse Health Complaints of Adults Exposed to Benzene After a Flaring Disaster at the BP Refinery Facility in Texas City, Texas. Disaster Med Public Health Prep 2017; 12:232-240. [PMID: 28877779 DOI: 10.1017/dmp.2017.59] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE The objective of this study was to assess the adverse health symptoms experienced by adult subjects who were exposed to benzene after a flaring disaster at the BP refinery in Texas City, Texas. METHODS A total of 2162 adults aged 18 years or older and exposed to benzene were included. Using the patients' medical charts, we collected and analyzed data on health complaints as well as the patients' serum levels of beta-2-microglobulin and urinary excretion of phenol. RESULTS A total of 11,368 health symptom complaints were reported in 2162 adults exposed to benzene. Neurological symptoms occurred most frequently (174%), followed upper respiratory symptoms (115%), cough (31%), painful joints (30%), cardiac symptoms (28%), dermatological symptoms (28%), gastrointestinal symptoms (27%), diarrhea (25%), vision symptoms (21%), and nausea/vomiting (19%). Logistic regression analysis indicated that urinary symptoms (R2=0.65) and painful joints (R2=0.44) were positively associated with increasing age in benzene-exposed subjects. CONCLUSION Adult subjects exposed to benzene experience a range of adverse health symptoms and an altered profile of urinary phenol, thus indicating they are at high risk of developing serious future health complications. (Disaster Med Public Health Preparedness. 2018;12:232-240).
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Gray JM, Rasanayagam S, Engel C, Rizzo J. State of the evidence 2017: an update on the connection between breast cancer and the environment. Environ Health 2017; 16:94. [PMID: 28865460 PMCID: PMC5581466 DOI: 10.1186/s12940-017-0287-4] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 07/17/2017] [Indexed: 05/23/2023]
Abstract
BACKGROUND In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available. CONCLUSION Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.
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Affiliation(s)
- Janet M. Gray
- Department of Psychology and Program in Science, Technology, and Society, Vassar College, 124 Raymond Avenue, Poughkeepsie, NY 12604-0246 USA
| | - Sharima Rasanayagam
- Breast Cancer Prevention Partners, 1388 Sutter St., Suite 400, San Francisco, CA 94109-5400 USA
| | - Connie Engel
- Breast Cancer Prevention Partners, 1388 Sutter St., Suite 400, San Francisco, CA 94109-5400 USA
| | - Jeanne Rizzo
- Breast Cancer Prevention Partners, 1388 Sutter St., Suite 400, San Francisco, CA 94109-5400 USA
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Fenga C. Occupational exposure and risk of breast cancer. Biomed Rep 2016; 4:282-292. [PMID: 26998264 DOI: 10.3892/br.2016.575] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 12/24/2015] [Indexed: 11/05/2022] Open
Abstract
Breast cancer is a multifactorial disease and the most commonly diagnosed cancer in women. Traditional risk factors for breast cancer include reproductive status, genetic mutations, family history and lifestyle. However, increasing evidence has identified an association between breast cancer and occupational factors, including environmental stimuli. Epidemiological and experimental studies demonstrated that ionizing and non-ionizing radiation exposure, night-shift work, pesticides, polycyclic aromatic hydrocarbons and metals are defined environmental factors for breast cancer, particularly at young ages. However, the mechanisms by which occupational factors can promote breast cancer initiation and progression remains to be elucidated. Furthermore, the evaluation of occupational factors for breast cancer, particularly in the workplace, also remains to be explained. The present review summarizes the occupational risk factors and the associated mechanisms involved in breast cancer development, in order to highlight new environmental exposures that could be correlated to breast cancer and to provide new insights for breast cancer prevention in the occupational settings. Furthermore, this review suggests that there is a requirement to include, through multidisciplinary approaches, different occupational exposure risks among those associated with breast cancer development. Finally, the design of new epigenetic biomarkers may be useful to identify the workers that are more susceptible to develop breast cancer.
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Affiliation(s)
- Concettina Fenga
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Occupational Medicine Section, 'Policlinico G. Martino' Hospital, University of Messina, Messina I-98125, Italy
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Ruckart PZ, Bove FJ, Shanley E, Maslia M. Evaluation of contaminated drinking water and male breast cancer at Marine Corps Base Camp Lejeune, North Carolina: a case control study. Environ Health 2015; 14:74. [PMID: 26376727 PMCID: PMC4571057 DOI: 10.1186/s12940-015-0061-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 09/08/2015] [Indexed: 05/28/2023]
Abstract
BACKGROUND Solvents contaminated drinking water supplies at Marine Corps Base Camp Lejeune during 1950s-1985. METHODS We conducted a case-control study among Marines to evaluate associations between residential exposure to contaminated drinking water at Camp Lejeune and male breast cancer risk. The study included 71 male breast cancer cases and 373 controls identified from the Department of Veteran's Affairs (VA) cancer registry whose military personnel records were available. Controls were selected from cancers not known to be associated with solvent exposure and included 270 skin cancers, 71 mesotheliomas, and 32 bone cancers. Base assignment and risk factor information came from military personnel and VA records. Groundwater contaminant fate/transport and distribution system models provided monthly estimated residential contaminant levels. We conducted exact logistic regression using the 50th percentile level among exposed controls to create low and high exposure categories. We calculated 95% confidence intervals (CIs) to indicate precision of effect estimates. Exploratory analyses used proportional hazards methods to evaluate associations between exposures and age at diagnosis. RESULTS After adjusting for age at diagnosis, race, and service in Vietnam, the odds ratio (OR) for ever stationed at Camp Lejeune was 1.14 (95% CI: 0.65, 1.97). Adjusted ORs for high residential cumulative exposures to tetrachloroethylene (PCE), t-1,2 dichloroethylene (DCE), and vinyl chloride were 1.20 [95% CI: 0.16-5.89], 1.50 [95% CI: 0.30-6.11], 1.19 [95% CI: 0.16-5.89], respectively, with a monotonic exposure response relationship for PCE only. However these results were based on two or three cases in the high cumulative exposure categories. Ever stationed at Camp Lejeune and high cumulative exposures to trichloroethylene (TCE), PCE, DCE and vinyl chloride were associated with earlier age at onset for male breast cancer; hazard ratios ranged from 1.4-2.7 with wide confidence intervals for cumulative exposure variables. CONCLUSION Findings suggested possible associations between male breast cancer and being stationed at Camp Lejeune and cumulative exposure to PCE, DCE, and vinyl chloride. TCE, PCE, DCE and vinyl chloride cumulative exposures showed possible associations with earlier age at onset of male breast cancer. However, this study was limited by small numbers of cases in high exposure categories.
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Affiliation(s)
- Perri Zeitz Ruckart
- Agency for Toxic Substances and Disease Registry, Division of Toxicology and Human Health Sciences, Atlanta, USA.
| | - Frank J Bove
- Agency for Toxic Substances and Disease Registry, Division of Toxicology and Human Health Sciences, Atlanta, USA.
| | - Edwin Shanley
- National Center for Environmental Health/Agency for Toxic Substances and Disease Registry, Office of the Director, Atlanta, USA.
| | - Morris Maslia
- Agency for Toxic Substances and Disease Registry, Division of Community Health Investigations, 4770 Buford Highway, MS F-58, Atlanta, GA, 30341, USA.
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Garcia E, Hurley S, Nelson DO, Hertz A, Reynolds P. Hazardous air pollutants and breast cancer risk in California teachers: a cohort study. Environ Health 2015; 14:14. [PMID: 25636809 PMCID: PMC4417287 DOI: 10.1186/1476-069x-14-14] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 07/21/2014] [Accepted: 01/21/2015] [Indexed: 05/08/2023]
Abstract
BACKGROUND Studies suggest that higher breast cancer rates in urban areas persist after accounting for the prevalence of known risk factors, leading to speculation that urban environmental exposures, such as air pollution, may play a role in the etiology of breast cancer. Combining modeled ambient air concentrations with data from a large prospective cohort of California women with over 15 years of follow-up, we examined the relationship between breast cancer incidence and modeled concentrations of air pollutants shown to be mammary gland carcinogens (MGCs). METHODS The study population of 112,378 California Teachers Study participants included 5,676 women diagnosed with invasive breast cancer. Modeled annual average ambient air concentrations of 24 MGCs from the U.S. Environmental Protection Agency were linked to participants' addresses. Cox proportional hazards models were used to estimate hazard rate ratios and 95% confidence intervals associated with residential MGC levels. MGCs were examined individually and as a combined summary variable for all participants, in selected subsets, and by tumor hormone responsiveness. RESULTS Initial models yielded some evidence for increased risk for several compounds, including acrylamide, carbon tetrachloride, chloroprene, 4,4'-methylene bis(2-chloroaniline), propylene oxide, and vinyl chloride, but after adjustment for multiple comparisons, only results for propylene oxide and vinyl chloride remained statistically significant. In subset analyses, estrogen-receptor positive or progesterone-receptor positive (ER+/PR+) tumors were associated with higher ambient levels of acrylamide, benzidine, carbon tetrachloride, ethylidene dichloride, and vinyl chloride, while ER-/PR- tumors were associated with higher ambient levels of benzene. Interesting results for different compounds were observed within certain subsets of the population. CONCLUSION While our initial models yielded several elevated risk estimates, after adjusting for multiple comparisons and breast cancer risk factors, most hazard ratios were no longer statistically significant. Our subset analyses, however, suggest that elevated risk may be associated with some compounds for certain subgroups of interest. A summary variable for all 24 MGCs did not offer any advantage over the models for individual compounds. Results must be interpreted cautiously, as estimated exposure was limited to modeled annual average ambient air concentrations, and could not account for other sources or routes other than inhalation.
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Affiliation(s)
- Erika Garcia
- />Cancer Prevention Institute of California, Berkeley, CA 94704 USA
- />School of Public Health, University of California, Berkeley, CA 94720 USA
| | - Susan Hurley
- />Cancer Prevention Institute of California, Berkeley, CA 94704 USA
| | - David O Nelson
- />Cancer Prevention Institute of California, Berkeley, CA 94704 USA
| | - Andrew Hertz
- />Cancer Prevention Institute of California, Berkeley, CA 94704 USA
| | - Peggy Reynolds
- />Cancer Prevention Institute of California, Berkeley, CA 94704 USA
- />Division of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, CA 94305 USA
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Bahadar H, Mostafalou S, Abdollahi M. Current understandings and perspectives on non-cancer health effects of benzene: a global concern. Toxicol Appl Pharmacol 2014; 276:83-94. [PMID: 24589379 DOI: 10.1016/j.taap.2014.02.012] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 02/02/2014] [Accepted: 02/19/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Benzene, as a volatile organic compound, is known as one of the main air pollutants in the environment. The aim of this review is to summarize all available evidences on non-cancerous health effects of benzene providing an overview of possible association of exposure to benzene with human chronic diseases, specially, in those regions of the world where benzene concentration is being poorly monitored. METHODOLOGY A bibliographic search of scientific databases including PubMed, Google Scholar, and Scirus was conducted with key words of "benzene toxic health effects", "environmental volatile organic compounds", "diabetes mellitus and environmental pollutants", "breast cancer and environmental pollution", "prevalence of lung cancer", and "diabetes prevalence". More than 300 peer reviewed papers were examined. Experimental and epidemiologic studies reporting health effects of benzene and volatile organic compounds were included in the study. RESULTS Epidemiologic and experimental studies suggest that benzene exposure can lead to numerous non-cancerous health effects associated with functional aberration of vital systems in the body like reproductive, immune, nervous, endocrine, cardiovascular, and respiratory. CONCLUSION Chronic diseases have become a health burden of global dimension with special emphasis in regions with poor monitoring over contents of benzene in petrochemicals. Benzene is a well known carcinogen of blood and its components, but the concern of benzene exposure is more than carcinogenicity of blood components and should be evaluated in both epidemiologic and experimental studies. Aspect of interactions and mechanism of toxicity in relation to human general health problems especially endocrine disturbances with particular reference to diabetes, breast and lung cancers should be followed up.
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Affiliation(s)
- Haji Bahadar
- International Campus, Tehran University of Medical Sciences, Iran; Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences, Iran
| | - Sara Mostafalou
- Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences, Iran
| | - Mohammad Abdollahi
- Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences, Iran.
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Mulware SJ. The mammary gland carcinogens: the role of metal compounds and organic solvents. Int J Breast Cancer 2013; 2013:640851. [PMID: 23762568 PMCID: PMC3671233 DOI: 10.1155/2013/640851] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Accepted: 04/24/2013] [Indexed: 11/18/2022] Open
Abstract
The increased rate of breast cancer incidences especially among postmenopausal women has been reported in recent decades. Despite the fact that women who inherited mutations in the BRCA1 and BRCA2 genes have a high risk of developing breast cancer, studies have also shown that significant exposure to certain metal compounds and organic solvents also increases the risks of mammary gland carcinogenesis. While physiological properties govern the uptake, intracellular distribution, and binding of metal compounds, their interaction with proteins seems to be the most relevant process for metal carcinogenicity than biding to DNA. The four most predominant mechanisms for metal carcinogenicity include (1) interference with cellular redox regulation and induction of oxidative stress, (2) inhibition of major DNA repair, (3) deregulation of cell proliferation, and (4) epigenetic inactivation of genes by DNA hypermethylation. On the other hand, most organic solvents are highly lipophilic and are biotransformed mainly in the liver and the kidney through a series of oxidative and reductive reactions, some of which result in bioactivation. The breast physiology, notably the parenchyma, is embedded in a fat depot capable of storing lipophilic xenobiotics. This paper reviews the role of metal compounds and organic solvents in breast cancer development.
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Affiliation(s)
- Stephen Juma Mulware
- Ion Beam Modification and Analysis Laboratory, Physics Department, University of North Texas, 1155 Union Circle, #311427, Denton, TX 76203, USA
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Sankpal UT, Pius H, Khan M, Shukoor MI, Maliakal P, Lee CM, Abdelrahim M, Connelly SF, Basha R. Environmental factors in causing human cancers: emphasis on tumorigenesis. Tumour Biol 2012; 33:1265-74. [PMID: 22614680 DOI: 10.1007/s13277-012-0413-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 04/30/2012] [Indexed: 01/22/2023] Open
Abstract
The environment and dietary factors play an essential role in the etiology of cancer. Environmental component is implicated in ~80 % of all cancers; however, the causes for certain cancers are still unknown. The potential players associated with various cancers include chemicals, heavy metals, diet, radiation, and smoking. Lifestyle habits such as smoking and alcohol consumption, exposure to certain chemicals (e.g., polycyclic aromatic hydrocarbons, organochlorines), metals and pesticides also pose risk in causing human cancers. Several studies indicated a strong association of lung cancer with the exposure to tobacco products and asbestos. The contribution of excessive sunlight, radiation, occupational exposure (e.g., painting, coal, and certain metals) is also well established in cancer. Smoking, excessive alcohol intake, consumption of an unhealthy diet, and lack of physical activity can act as risk factors for cancer and also impact the prognosis. Even though the environmental disposition is linked to cancer, the level and duration of carcinogen-exposure and associated cellular and biochemical aspects determine the actual risk. Modulations in metabolism and DNA adduct formation are considered central mechanisms in environmental carcinogenesis. This review describes the major environmental contributors in causing cancer with an emphasis on molecular aspects associated with environmental disposition in carcinogenesis.
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Affiliation(s)
- Umesh T Sankpal
- Cancer Research Institute, MD Anderson Cancer Center Orlando, 6900 Lake Nona Blvd, Orlando, FL 32827, USA
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Rodriguez B, Yang Y, Guliaev AB, Chenna A, Hang B. Benzene-derived N2-(4-hydroxyphenyl)-deoxyguanosine adduct: UvrABC incision and its conformation in DNA. Toxicol Lett 2009; 193:26-32. [PMID: 20006688 DOI: 10.1016/j.toxlet.2009.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 12/03/2009] [Accepted: 12/03/2009] [Indexed: 10/20/2022]
Abstract
Benzene, a ubiquitous human carcinogen, forms DNA adducts through its metabolites such as p-benzoquinone (p-BQ) and hydroquinone (HQ). N(2)-(4-Hydroxyphenyl)-2'-deoxyguanosine (N(2)-4-HOPh-dG) is the principal adduct identified in vivo by (32)P-postlabeling in cells or animals treated with p-BQ or HQ. To study its effect on repair specificity and replication fidelity, we recently synthesized defined oligonucleotides containing a site-specific adduct using phosphoramidite chemistry. We here report the repair of this adduct by Escherichia coli UvrABC complex, which performs the initial damage recognition and incision steps in the nucleotide excision repair (NER) pathway. We first showed that the p-BQ-treated plasmid was efficiently cleaved by the complex, indicating the formation of DNA lesions that are substrates for NER. Using a 40-mer substrate, we found that UvrABC incises the DNA strand containing N(2)-4-HOPh-dG in a dose- and time-dependent manner. The specificity of such repair was also compared with that of DNA glycosylases and damage-specific endonucleases of E. coli, both of which were found to have no detectable activity toward N(2)-4-HOPh-dG. To understand why this adduct is specifically recognized and processed by UvrABC, molecular modeling studies were performed. Analysis of molecular dynamics trajectories showed that stable G:C-like hydrogen bonding patterns of all three Watson-Crick hydrogen bonds are present within the N(2)-4-HOPh-G:C base pair, with the hydroxyphenyl ring at an almost planar position. In addition, N(2)-4-HOPh-dG has a tendency to form more stable stacking interactions than a normal G in B-type DNA. These conformational properties may be critical in differential recognition of this adduct by specific repair enzymes.
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Affiliation(s)
- Ben Rodriguez
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA 94132, USA
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