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Nuta O, Bouffler S, Lloyd D, Ainsbury E, Sepai O, Rothkamm K. Investigating the impact of long term exposure to chemical agents on the chromosomal radiosensitivity using human lymphoblastoid GM1899A cells. Sci Rep 2021; 11:12616. [PMID: 34135387 PMCID: PMC8209142 DOI: 10.1038/s41598-021-91957-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 05/27/2021] [Indexed: 11/09/2022] Open
Abstract
This study aimed to investigate the impact of chronic low-level exposure to chemical carcinogens with different modes of action on the cellular response to ionising radiation. Human lymphoblastoid GM1899A cells were cultured in the presence of 4-nitroquinoline N-oxide (4NQO), N-nitroso-N-methylurea (MNU) and hydrogen peroxide (H2O2) for up to 6 months at the highest non-(geno)toxic concentration identified in pilot experiments. Acute challenge doses of 1 Gy X-rays were given and chromosome damage (dicentrics, acentric fragments, micronuclei, chromatid gaps/breaks) was scored. Chronic exposure to 20 ng/ml 4NQO, 0.25 μg/ml MNU or 10 μM H2O2 hardly induced dicentrics and did not significantly alter the yield of X-ray-induced dicentrics. Significant levels of acentric fragments were induced by all chemicals, which did not change during long-term exposure. Fragment data in combined treatment samples compared to single treatments were consistent with an additive effect of chemical and radiation exposure. Low level exposure to 4NQO induced micronuclei, the yields of which did not change throughout the 6 month exposure period. As for fragments, micronuclei yields for combined treatments were consistent with an additive effect of chemical and radiation. These results suggest that cellular radiation responses are not affected by long-term low-level chemical exposure.
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Affiliation(s)
- Otilia Nuta
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, OX11 0RQ, Oxon, UK.
- Department of Biology, School of Sciences and Humanities, Nazarbayev University, Kabanbay Batyr 53, 01000, Nur-Sultan, Kazakhstan.
| | - Simon Bouffler
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, OX11 0RQ, Oxon, UK
| | - David Lloyd
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, OX11 0RQ, Oxon, UK
| | - Elizabeth Ainsbury
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, OX11 0RQ, Oxon, UK
| | - Ovnair Sepai
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, OX11 0RQ, Oxon, UK
| | - Kai Rothkamm
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, OX11 0RQ, Oxon, UK
- Department of Radiotherapy and Radiation Oncology, University Medical Center Hamburg- Eppendorf, 20246, Hamburg, Germany
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Imaoka T, Nishimura M, Doi K, Tani S, Ishikawa KI, Yamashita S, Ushijima T, Imai T, Shimada Y. Molecular characterization of cancer reveals interactions between ionizing radiation and chemicals on rat mammary carcinogenesis. Int J Cancer 2013; 134:1529-38. [PMID: 24105445 DOI: 10.1002/ijc.28480] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 08/27/2013] [Indexed: 11/06/2022]
Abstract
Although various mechanisms have been inferred for combinatorial actions of multiple carcinogens, these mechanisms have not been well demonstrated in experimental carcinogenesis models. We evaluated mammary carcinogenesis initiated by combined exposure to various doses of radiation and chemical carcinogens. Female rats at 7 weeks of age were γ-irradiated (0.2-2 Gy) and/or exposed to 1-methyl-1-nitrosourea (MNU) (20 or 40 mg/kg, single intraperitoneal injection) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) (40 mg/kg/day by gavage for 10 days) and were observed until 50 weeks of age. The incidence of mammary carcinoma increased steadily as a function of radiation dose in the absence of chemicals; mathematical analysis supported an additive increase when radiation was combined with a chemical carcinogen, irrespective of the chemical species and its dose. Hras mutations were characteristic of carcinomas that developed after chemical carcinogen treatments and were overrepresented in carcinomas induced by the combination of radiation and MNU (but not PhIP), indicating an interaction of radiation and MNU at the level of initiation. The expression profiles of seven classifier genes, previously shown to distinguish two classes of rat mammary carcinomas, categorized almost all examined carcinomas that developed after individual or combined treatments with radiation (1 Gy) and chemicals as belonging to a single class; more comprehensive screening using microarrays and a separate test sample set failed to identify differences in gene expression profiles among these carcinomas. These results suggest that a complex, multilevel interaction underlies the combinatorial action of radiation and chemical carcinogens in the experimental model.
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Affiliation(s)
- Tatsuhiko Imaoka
- Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Japan; Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, Japan
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Hirano S, Kakinuma S, Amasaki Y, Nishimura M, Imaoka T, Fujimoto S, Hino O, Shimada Y. Ikaros is a critical target during simultaneous exposure to X-rays and N-ethyl-N-nitrosourea in mouse T-cell lymphomagenesis. Int J Cancer 2013; 132:259-68. [PMID: 22684892 DOI: 10.1002/ijc.27668] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 05/21/2012] [Indexed: 11/09/2022]
Abstract
Cancer risk associated with radiation exposure is considered the result of concurrent exposure to other natural and manmade carcinogens. Available data on the molecular characteristics of cancer after simultaneous exposure to radiation and chemicals are insufficient. In our study, we used a mouse thymic lymphoma (TL) model that was synergistically induced by simultaneous exposure to X-rays and N-ethyl-N-nitrosourea (ENU) at subcarcinogenic doses and analyzed the mutation frequency and spectrum of the TL-associated genes Ikaros, Notch1, p53 and Kras. We found that the point mutation frequency in Ikaros was significantly increased to 47% for simultaneous exposure compared to 13 and 0% for X-ray and ENU exposure alone, respectively. These mutations were mostly G:C > A:T at non-CpG sites and T:A > C:G, both of which are characteristic of ENU mutagenesis. About half of the point mutations were accompanied by loss of heterozygosity (LOH), typical of X-irradiation. The remaining half did not include LOH, which suggests that they were dominant-negative mutations. In Notch1, the frequency of abnormalities was high (>58%) regardless of the treatment, suggesting that Notch1 aberration may be important for T-cell lymphomagenesis. The p53 and Kras mutation frequencies were low for all treatments (<23%). Importantly, the frequency of TLs containing mutations in multiple genes, especially both Ikaros and Notch1, increased after simultaneous exposure. Thus, after simultaneous exposure, Ikaros is a critical target and is inactivated by ENU-induced point mutations and/or X-ray-induced LOH in T-cell lymphomagenesis. Furthermore, concomitant alterations of multiple tumor-associated genes may contribute to enhanced lymphomagenesis after simultaneous exposure.
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Affiliation(s)
- Shinobu Hirano
- Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Inage-Ku, Chiba, Japan
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Lewis AS, Sax SN, Wason SC, Campleman SL. Non-chemical stressors and cumulative risk assessment: an overview of current initiatives and potential air pollutant interactions. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2011; 8:2020-73. [PMID: 21776216 PMCID: PMC3138011 DOI: 10.3390/ijerph8062020] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/24/2011] [Accepted: 05/20/2011] [Indexed: 12/30/2022]
Abstract
Regulatory agencies are under increased pressure to consider broader public health concerns that extend to multiple pollutant exposures, multiple exposure pathways, and vulnerable populations. Specifically, cumulative risk assessment initiatives have stressed the importance of considering both chemical and non-chemical stressors, such as socioeconomic status (SES) and related psychosocial stress, in evaluating health risks. The integration of non-chemical stressors into a cumulative risk assessment framework has been largely driven by evidence of health disparities across different segments of society that may also bear a disproportionate risk from chemical exposures. This review will discuss current efforts to advance the field of cumulative risk assessment, highlighting some of the major challenges, discussed within the construct of the traditional risk assessment paradigm. Additionally, we present a summary of studies of potential interactions between social stressors and air pollutants on health as an example of current research that supports the incorporation of non-chemical stressors into risk assessment. The results from these studies, while suggestive of possible interactions, are mixed and hindered by inconsistent application of social stress indicators. Overall, while there have been significant advances, further developments across all of the risk assessment stages (i.e., hazard identification, exposure assessment, dose-response, and risk characterization) are necessary to provide a scientific basis for regulatory actions and effective community interventions, particularly when considering non-chemical stressors. A better understanding of the biological underpinnings of social stress on disease and implications for chemical-based dose-response relationships is needed. Furthermore, when considering non-chemical stressors, an appropriate metric, or series of metrics, for risk characterization is also needed. Cumulative risk assessment research will benefit from coordination of information from several different scientific disciplines, including, for example, toxicology, epidemiology, nutrition, neurotoxicology, and the social sciences.
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Affiliation(s)
- Ari S. Lewis
- Gradient, 20 University Road, Cambridge, MA 02138, USA; E-Mail:
| | - Sonja N. Sax
- Gradient, 20 University Road, Cambridge, MA 02138, USA; E-Mail:
| | - Susan C. Wason
- Department of Environmental Health, Harvard School of Public Health, 401 Park Drive, Boston, MA 02215, USA; E-Mail:
| | - Sharan L. Campleman
- Electric Power Research Institute, 3420 Hillview Ave., Palo Alto, CA 94304, USA; E-Mail:
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García-Talavera M, Matarranz JLM, Salas R, Ramos L. A regulatory perspective on the radiological impact of NORM industries: the case of the Spanish phosphate industry. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2011; 102:1-7. [PMID: 20952107 DOI: 10.1016/j.jenvrad.2010.08.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 08/12/2010] [Accepted: 08/25/2010] [Indexed: 05/30/2023]
Abstract
Radioactive and chemical risks coexist in NORM industries although they are usually addressed separately by regulations. The European Union (EU) has developed extensive legislation concerning both matters, which has been diversely reflected in national policies. We consider the case of the Spanish phosphate industry and analyse to which extent regulatory mandates have reduced the historical and ongoing radiological impact on the environment of phosphate facilities. Although no specific radiological constraints on effluent monitoring and release or on waste disposal have yet been imposed on NORM industries in Spain, other environmental regulations have achieved a substantial reduction on the phosphate industry impact. Nevertheless, a more efficient control could be established by eliminating the current conceptual and practical separation of chemical and radioactive risks in NORM industries. We highlight research needs to accomplish so and propose shorter-term measures that require active cooperation among the regulatory bodies involved.
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Affiliation(s)
- M García-Talavera
- Consejo de Seguridad Nuclear (CSN), Justo Dorado, 11, E-28040 Madrid, Spain.
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McKone TE, Ryan PB, Ozkaynak H. Exposure information in environmental health research: current opportunities and future directions for particulate matter, ozone, and toxic air pollutants. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2009; 19:30-44. [PMID: 18385670 DOI: 10.1038/jes.2008.3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Accepted: 01/04/2008] [Indexed: 05/26/2023]
Abstract
Understanding and quantifying outdoor and indoor sources of human exposure are essential but often not adequately addressed in health effect studies for air pollution. Air pollution epidemiology, risk assessment, health tracking, and accountability assessments are examples of health effect studies that require but often lack adequate exposure information. Recent advances in exposure modeling along with better information on time-activity and exposure factor data provide us with unique opportunities to improve the assignment of exposures for both future and ongoing studies linking air pollution to health impacts. In September 2006, scientists from the US Environmental Protection Agency and the Centers for Disease Control and Prevention along with scientists from the academic community and state health departments convened a symposium on air pollution exposure and health to identify, evaluate, and improve current approaches for linking air pollution exposures to disease. This manuscript presents the key issues, challenges, and recommendations identified by the exposure working group, who used case studies of particulate matter, ozone, and toxic air-pollutant exposure to evaluate health effects for air pollution. One of the overarching lessons of this workshop is that obtaining better exposure information for these different health effect studies requires both goal setting for what is needed and mapping out the transition pathway from current capabilities for meeting these goals. Meeting our long-term goals requires definition of incremental steps that provide useful information for the interim and move us toward our long-term goals. Another overarching theme among the three different pollutants and the different health study approaches is the need for integration among alternate exposure-assessment approaches. For example, different groups may advocate exposure indicators, biomonitoring, mapping methods (GIS), modeling, environmental media monitoring, and/or personal exposure modeling. However, emerging research reveals that the greatest progress comes from integration among two or more of these efforts.
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Affiliation(s)
- Thomas E McKone
- Lawrence Berkeley National Laboratory, Berkeley, California 95720, USA.
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Eissinger F. Interactions génome-environnement dans les cancers liés aux expositions professionnelles. ARCH MAL PROF ENVIRO 2006. [DOI: 10.1016/s1775-8785(06)78155-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Imaoka T, Nishimura M, Teramoto A, Nishimura Y, Ootawara M, Osada H, Kakinuma S, Maekawa A, Shimada Y. Cooperative induction of rat mammary cancer by radiation and 1-methyl-1-nitrosourea via the oncogenic pathways involving c-Myc activation and H-ras mutation. Int J Cancer 2005; 115:187-93. [PMID: 15688392 DOI: 10.1002/ijc.20904] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Humans are continually exposed to various environmental carcinogens. Cancers may arise as a result of exposure to carcinogenic chemicals, ionizing radiation or a combination thereof. However, the mechanism of combined carcinogenesis has been only deduced from oncogenic actions of individual agents. Here, we analyzed experimental mammary carcinogenesis caused by a combination of radiation and a chemical carcinogen, 1-methyl-1-nitrosourea (MNU). Seven-week-old female Sprague-Dawley rats were divided into 4 groups: control, g gamma-irradiated (2 Gy), MNU-treated (40 mg/kg, i.p.) and combined treatment of radiation with subsequent MNU after 3 days. Rats with palpable tumors were sacrificed at 50 weeks of age to collect tumors for histologic typing and mutational analysis of the H-ras gene codon 12. The combined treatment induced adenocarcinomas, but not fibroadenomas, more efficiently than radiation or MNU alone. The H-ras mutation was not seen in radiation-induced carcinomas and was specific to MNU-induced carcinomas in individually treated groups. In the combined treatment group, H-ras-mutated, but not nonmutated, tumors were more frequent and developed significantly earlier than in the MNU-treated group. Significantly higher numbers of cells were stained for activated c-Myc protein in g gamma-ray- and combined treatment-induced cancers than in MNU-induced cancers. These results indicate that combined exposure to the 2 carcinogens elicits an unexpected cooperativity in which pre-irradiation enhances mammary carcinogenesis predominantly through the oncogenic pathway involving H-ras, possibly by synergism with c-Myc activation.
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Affiliation(s)
- Tatsuhiko Imaoka
- Research Center for Radiation Safety, National Institute of Radiological Sciences, Anagawa, Chiba, Japan
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