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Högberg J, Järnberg J. Approaches for the setting of occupational exposure limits (OELs) for carcinogens. Crit Rev Toxicol 2023:1-37. [PMID: 37366107 DOI: 10.1080/10408444.2023.2218887] [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: 02/23/2023] [Revised: 05/12/2023] [Accepted: 05/22/2023] [Indexed: 06/28/2023]
Abstract
This article addresses issues of importance for occupational exposure limits (OELs) and chemical carcinogens with a focus on non-threshold carcinogens. It comprises scientific as well as regulatory issues. It is an overview, not a comprehensive review. A central topic is mechanistic research and insights, and its implications for cancer risk assessment. Alongside scientific advancements, the approaches of hazard identification and qualitative and quantitative risk assessment have developed over the years. The key steps in a quantitative risk assessment are outlined, with special attention given to the dose-response assessment and the derivation of an OEL using risk calculations or default assessment factors. The work procedures of several bodies performing cancer hazard identifications and quantitative risk assessments, as well as regulatory procedures to derive OELs for non-threshold carcinogens, are presented. Non-threshold carcinogens for which the European Union (EU) introduced binding OELs in 2017-2019 serve as illustrations together with some currently used strategies in the EU and elsewhere. Available knowledge supports the derivation of health-based OELs (Hb-OELs) for non-threshold carcinogens, and the use of a risk-based approach with low-dose linear extrapolation (linear non-threshold, LNT) as the default for non-threshold carcinogens. However, there is a need to develop methods that allow recent years' advances in cancer research to be used for improving risk estimates. It is recommended that defined risk levels (terminology and numerical values) are harmonised, and that both collective and individual risks are considered and clearly communicated. Socioeconomic aspects should be dealt with transparently and separated from the scientific health risk assessment.
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Affiliation(s)
- Johan Högberg
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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Zhang X, Guo N, Jin H, Liu R, Zhang Z, Cheng C, Fan Z, Zhang G, Xiao M, Wu S, Zhao Y, Lu X. Bisphenol A drives di(2-ethylhexyl) phthalate promoting thyroid tumorigenesis via regulating HDAC6/PTEN and c-MYC signaling. JOURNAL OF HAZARDOUS MATERIALS 2022; 425:127911. [PMID: 34910997 DOI: 10.1016/j.jhazmat.2021.127911] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
Bisphenol A (BPA) and di-(2-ethylhcxyl) phthalate (DEHP) are exist widespread in the environment and produce adverse effect to human as environmental disruptors (EDCs). Epidemiological studies have found that the exposure of DEHP and BPA could increase the susceptibility to thyroid diseases including thyroid cancer and benign thyroid nodules. Due to the existence of multiple pollutants in our daily life, the mixed toxic effects of exposure and their interrelationships may distinguish from the exposure to a single chemical, so it is of great significance to explore the mixed toxic effect of DEHP and BPA co-exposure. Thyroid, as one of the target organs of EDCs, is prone to tumor occurrence, however, whether the mixture of BPA and DEHP will affect the occurrence of thyroid cancer is still obscure. We aim to investigate the effect of single or combined exposure to BPA and DEHP on the occurrence of thyroid cancer. An animal model of exposure to BPA and DEHP was firstly established to evaluate their effect on DMD-induced thyroid cancer. Additionally, human thyroid cancer cells BCPAP and thyroid cells Nthy-ori3-1 were used to further clarify some possible mechanisms of BPA and MEHP, the main metabolite of DEHP. Consequently, we found that BPA alone could increase the incidence of thyroid tumors in female rats compared with DEHP, and DEHP enhanced the effect of BPA on cancer promotion. BPA alone and in combination with DEHP mainly induced the expression of HDAC6, inhibited tumor suppressor gene PTEN upregulated the expression of oncogene c-MYC, and eventually elevate the susceptibility to thyroid tumors. Mechanistically, BPA alone and in combination with MEHP could significantly induce the proliferation of BCPAP cells depending on HDAC6, which could modulate H3K9ac to inhibit PTEN, activate AKT signaling pathway, and simultaneously upregulate the expression of c-MYC. Interestingly, we found that BPA alone and in combination with MEHP could significantly induce the proliferation of Nthy-ori3-1 cells independent on HDAC6 via activating ERK signaling pathway. Taken together, these findings not only provide new evidence of the promoting effect of BPA and DEHP on thyroid cancer but also discusses some possible mechanisms underlying these effects.
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Affiliation(s)
- Xuan Zhang
- Department of Toxicology, School of Public health, China Medical University, Shenyang, PR China
| | - Nan Guo
- Department of head and Neck Surgery, Cancer hospital of China Medical University/Liaoning Cancer hospital & Institute, Shenyang, PR China
| | - Hao Jin
- Jin Zhou Center for Disease Control and Prevention, Jinzhou, PR China
| | - Renqi Liu
- Jin Zhou Center for Disease Control and Prevention, Jinzhou, PR China
| | - Zhen Zhang
- Jin Zhou Center for Disease Control and Prevention, Jinzhou, PR China
| | - Cheng Cheng
- Department of Toxicology, School of Public health, China Medical University, Shenyang, PR China
| | - Zhijun Fan
- Department of Toxicology, School of Public health, China Medical University, Shenyang, PR China
| | - Guopei Zhang
- Department of Toxicology, School of Public health, China Medical University, Shenyang, PR China
| | - Mingyang Xiao
- Department of Toxicology, School of Public health, China Medical University, Shenyang, PR China
| | - Shengwen Wu
- Department of Toxicology, School of Public health, China Medical University, Shenyang, PR China
| | - Yuejiao Zhao
- Department of head and Neck Surgery, Cancer hospital of China Medical University/Liaoning Cancer hospital & Institute, Shenyang, PR China.
| | - Xiaobo Lu
- Department of Toxicology, School of Public health, China Medical University, Shenyang, PR China.
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Zhang X, Cheng C, Zhang G, Xiao M, Li L, Wu S, Lu X. Co-exposure to BPA and DEHP enhances susceptibility of mammary tumors via up-regulating Esr1/HDAC6 pathway in female rats. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 221:112453. [PMID: 34186418 DOI: 10.1016/j.ecoenv.2021.112453] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 06/20/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Breast cancer (BrCa) as one of the major malignancies threatening women's health worldwide occurs due to the genetic and environmental interactions. Epidemiological studies have suggested that exposure to endocrine disrupting chemicals (EDCs) can elevate the risk of breast cancer. Di-(2-ethylhexyl)-phthalate (DEHP) and bisphenol A (BPA) are known as two typical EDCs. Although several studies have implied that there appear to have adverse effects of exposure to BPA or DEHP alone on breast development, no study to date has demonstrated the exact toxic effect of combined exposure to DEHP and BPA on breast tumorigenesis. In the present study, we performed an in vivo experiment including 160 female Sprague-Dawley (SD) rats, in which 80 rats were randomly allocated to 4 groups including control group given to normal diet, DEHP (150 mg/kg body weight/day), BPA (20 mg/kg body weight/day), and DEHP (150 mg/kg body weight/day) combined with BPA (20 mg/kg body weight/day) by gavage for 30 weeks. Additionally, a DEN/MNU/DHPN (DMD)-induced carcinogenesis animal model was also established to assess their effect on tumor promotion. Namely, the other 80 SD rats were separated into another 4 groups: in addition to DMD initiation each group treated with vehicle, DEHP, BPA and the combination of BPA and DEHP respectively. Our data demonstrated that BPA alone or in combination with DEHP may induce hyperplasia of mammary glands, including the proliferation of ductal epithelial cells and an increase in the number of lobules and acinus after a 30-week exposure. Notably, co-exposure to DEHP and BPA increased the incidence and reduced the latency of mammary tumor, which seemed to enhance the susceptibility of carcinogens-induced tumor. Mechanistically, our results supported the hypothesis that exposure to BPA and DEHP might promote breast cancer dependent on Esr1 and HDAC6 as pivotal factors, and further lead to the activation of oncogene c-Myc. Our study suggested that BPA combined with DEHP facilitate the occurrence of mammary tumors, which contributed to advance our understanding in the complex effects of compound exposure to endocrine disrupting chemicals.
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Affiliation(s)
- Xuan Zhang
- Department of Toxicology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New District, Shenyang 110122, Liaoning Province, PR China.
| | - Cheng Cheng
- Department of Toxicology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New District, Shenyang 110122, Liaoning Province, PR China.
| | - Guopei Zhang
- Department of Toxicology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New District, Shenyang 110122, Liaoning Province, PR China.
| | - Mingyang Xiao
- Department of Toxicology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New District, Shenyang 110122, Liaoning Province, PR China.
| | - Liuli Li
- Department of Toxicology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New District, Shenyang 110122, Liaoning Province, PR China.
| | - Shengwen Wu
- Department of Toxicology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New District, Shenyang 110122, Liaoning Province, PR China.
| | - Xiaobo Lu
- Department of Toxicology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New District, Shenyang 110122, Liaoning Province, PR China.
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Ali I, Dreij K, Baker S, Högberg J, Korhonen A, Stenius U. Application of Text Mining in Risk Assessment of Chemical Mixtures: A Case Study of Polycyclic Aromatic Hydrocarbons (PAHs). ENVIRONMENTAL HEALTH PERSPECTIVES 2021; 129:67008. [PMID: 34165340 PMCID: PMC8318069 DOI: 10.1289/ehp6702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 05/08/2023]
Abstract
BACKGROUND Cancer risk assessment of complex exposures, such as exposure to mixtures of polycyclic aromatic hydrocarbons (PAHs), is challenging due to the diverse biological activities of these compounds. With the help of text mining (TM), we have developed TM tools-the latest iteration of the Cancer Risk Assessment using Biomedical literature tool (CRAB3) and a Cancer Hallmarks Analytics Tool (CHAT)-that could be useful for automatic literature analyses in cancer risk assessment and research. Although CRAB3 analyses are based on carcinogenic modes of action (MOAs) and cover almost all the key characteristics of carcinogens, CHAT evaluates literature according to the hallmarks of cancer referring to the alterations in cellular behavior that characterize the cancer cell. OBJECTIVES The objective was to evaluate the usefulness of these tools to support cancer risk assessment by performing a case study of 22 European Union and U.S. Environmental Protection Agency priority PAHs and diesel exhaust and a case study of PAH interactions with silica. METHODS We analyzed PubMed literature, comprising 57,498 references concerning priority PAHs and complex PAH mixtures, using CRAB3 and CHAT. RESULTS CRAB3 analyses correctly identified similarities and differences in genotoxic and nongenotoxic MOAs of the 22 priority PAHs and grouped them according to their known carcinogenic potential. CHAT had the same capacity and complemented the CRAB output when comparing, for example, benzo[a]pyrene and dibenzo[a,l]pyrene. Both CRAB3 and CHAT analyses highlighted potentially interacting mechanisms within and across complex PAH mixtures and mechanisms of possible importance for interactions with silica. CONCLUSION These data suggest that our TM approach can be useful in the hazard identification of PAHs and mixtures including PAHs. The tools can assist in grouping chemicals and identifying similarities and differences in carcinogenic MOAs and their interactions. https://doi.org/10.1289/EHP6702.
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Affiliation(s)
- Imran Ali
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Kristian Dreij
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Simon Baker
- Department of Theoretical and Applied Linguistics, University of Cambridge, Cambridge, UK
| | - Johan Högberg
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Anna Korhonen
- Department of Theoretical and Applied Linguistics, University of Cambridge, Cambridge, UK
| | - Ulla Stenius
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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