1
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Brandner S. Rodent models of tumours of the central nervous system. Mol Oncol 2024. [PMID: 39324445 DOI: 10.1002/1878-0261.13729] [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: 11/19/2023] [Revised: 07/03/2024] [Accepted: 08/23/2024] [Indexed: 09/27/2024] Open
Abstract
Modelling of human diseases is an essential component of biomedical research, to understand their pathogenesis and ultimately, develop therapeutic approaches. Here, we will describe models of tumours of the central nervous system, with focus on intrinsic CNS tumours. Model systems for brain tumours were established as early as the 1920s, using chemical carcinogenesis, and a systematic analysis of different carcinogens, with a more refined histological analysis followed in the 1950s and 1960s. Alternative approaches at the time used retroviral carcinogenesis, allowing a more topical, organ-centred delivery. Most of the neoplasms arising from this approach were high-grade gliomas. Whilst these experimental approaches did not directly demonstrate a cell of origin, the localisation and growth pattern of the tumours already pointed to an origin in the neurogenic zones of the brain. In the 1980s, expression of oncogenes in transgenic models allowed a more targeted approach by expressing the transgene under tissue-specific promoters, whilst the constitutive inactivation of tumour suppressor genes ('knock out')-often resulted in embryonic lethality. This limitation was elegantly solved by engineering the Cre-lox system, allowing for a promoter-specific, and often also time-controlled gene inactivation. More recently, the use of the CRISPR Cas9 technology has significantly increased experimental flexibility of gene expression or gene inactivation and thus added increased value of rodent models for the study of pathogenesis and establishing preclinical models.
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Affiliation(s)
- Sebastian Brandner
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology and Division of Neuropathology, The National Hospital for Neurology and Neurosurgery, University College London Hospitals, NHS Foundation Trust, London, UK
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2
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Yaakub H, Howell A, Margison GP, Povey AC. Development and Application of a Slot-Blot Assay Using the Damage Sensing Protein Atl1 to Detect and Quantify O6-Alkylated Guanine Bases in DNA. TOXICS 2024; 12:649. [PMID: 39330577 PMCID: PMC11435591 DOI: 10.3390/toxics12090649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Revised: 08/30/2024] [Accepted: 09/02/2024] [Indexed: 09/28/2024]
Abstract
Humans are unavoidably exposed to numerous different mutagenic DNA alkylating agents (AAs), but their role in the initiation of cancers is uncertain, in part due to difficulties in assessing human exposure. To address this, we have developed a screening method that measures promutagenic O6-alkylguanines (O6-AlkGs) in DNA and applied it to human DNA samples. The method exploits the ability of the Schizosaccharomyces pombe alkyltransferase-like protein (Atl1) to recognise and bind to a wide range of O6-AlkGs in DNA. We established an Atl1-based slot-blot (ASB) assay and validated it using calf thymus DNA alkylated in vitro with a range of alkylating agents and both calf thymus and human placental DNA methylated in vitro with temozolomide (TMZ). ASB signals were directly proportional to the levels of O6-meG in these controls. Pre-treatment of DNA with the DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) reduced binding of Atl1, confirming its specificity. In addition, MCF 10A cells were treated with 500 μM TMZ and the extracted DNA, analysed using the ASB, was found to contain 1.34 fmoles O6 -meG/μg DNA. Of six human breast tumour DNA samples assessed, five had detectable O6-AlkG levels (mean ± SD 1.24 ± 0.25 O6-meG equivalents/μg DNA. This study shows the potential usefulness of the ASB assay to detect and quantify total O6-AlkGs in human DNA samples.
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Affiliation(s)
- Hanum Yaakub
- Epidemiology and Public Health Group, Division of Population Health, Health Services Research and Primary Care, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (H.Y.); (G.P.M.)
| | - Anthony Howell
- Prevent Breast Cancer Centre, Wythenshawe Hospital Manchester Universities Foundation Trust, Wythenshawe, Manchester M23 9LT, UK;
- Manchester Breast Centre, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4GJ, UK
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
| | - Geoffrey P. Margison
- Epidemiology and Public Health Group, Division of Population Health, Health Services Research and Primary Care, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (H.Y.); (G.P.M.)
| | - Andrew C. Povey
- Epidemiology and Public Health Group, Division of Population Health, Health Services Research and Primary Care, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (H.Y.); (G.P.M.)
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3
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Yu S, McWilliams JC, Dirat O, Dobo KL, Kalgutkar AS, Kenyon MO, Martin MT, Watt ED, Schuler M. A Kinetic Model for Assessing Potential Nitrosamine Carcinogenicity. Chem Res Toxicol 2024; 37:1382-1393. [PMID: 39075630 DOI: 10.1021/acs.chemrestox.4c00133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Understanding the potential carcinogenic potency of nitrosamines is necessary to setting acceptable intake limits. Nitrosamines and the components that can form them are commonly present in food, water, cosmetics, and tobacco. The recent observation of nitrosamines in pharmaceuticals highlighted the need for effective methods to determine acceptable intake limits. Herein, we describe two computational models that utilize properties based upon quantum mechanical calculations in conjunction with mechanistic insights and established data to determine the carcinogenic potency of a variety of common nitrosamines. These models can be applied to experimentally untested nitrosamines to aid in the establishment of acceptable intake limits.
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Affiliation(s)
- Shu Yu
- Chemical Research and Development, Pfizer Research & Development, Groton, Connecticut 06340, United States
| | - J Christopher McWilliams
- Chemical Research and Development, Pfizer Research & Development, Groton, Connecticut 06340, United States
| | - Olivier Dirat
- CMC Advisory Office, Pfizer Global Regulatory Sciences, Sandwich CT13 9NJ, U.K
| | - Krista L Dobo
- Drug Safety Research and Development, Pfizer Research & Development-Groton Laboratories, Groton, Connecticut 06340, United States
| | - Amit S Kalgutkar
- Pharmacokinetics Dynamics and Metabolism, Pfizer Research & Development, Cambridge, Massachusetts 02139, United States
| | - Michelle O Kenyon
- Drug Safety Research and Development, Pfizer Research & Development-Groton Laboratories, Groton, Connecticut 06340, United States
| | - Matthew T Martin
- Drug Safety Research and Development, Pfizer Research & Development-Groton Laboratories, Groton, Connecticut 06340, United States
| | - Eric D Watt
- Drug Safety Research and Development, Pfizer Research & Development-Groton Laboratories, Groton, Connecticut 06340, United States
| | - Maik Schuler
- Drug Safety Research and Development, Pfizer Research & Development-Groton Laboratories, Groton, Connecticut 06340, United States
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4
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Kruhlak NL, Schmidt M, Froetschl R, Graber S, Haas B, Horne I, Horne S, King ST, Koval IA, Kumaran G, Langenkamp A, McGovern TJ, Peryea T, Sanh A, Siqueira Ferreira A, van Aerts L, Vespa A, Whomsley R. Determining recommended acceptable intake limits for N-nitrosamine impurities in pharmaceuticals: Development and application of the Carcinogenic Potency Categorization Approach (CPCA). Regul Toxicol Pharmacol 2024; 150:105640. [PMID: 38754805 DOI: 10.1016/j.yrtph.2024.105640] [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: 04/22/2024] [Accepted: 05/06/2024] [Indexed: 05/18/2024]
Abstract
N-Nitrosamine impurities, including nitrosamine drug substance-related impurities (NDSRIs), have challenged pharmaceutical industry and regulators alike and affected the global drug supply over the past 5 years. Nitrosamines are a class of known carcinogens, but NDSRIs have posed additional challenges as many lack empirical data to establish acceptable intake (AI) limits. Read-across analysis from surrogates has been used to identify AI limits in some cases; however, this approach is limited by the availability of robustly-tested surrogates matching the structural features of NDSRIs, which usually contain a diverse array of functional groups. Furthermore, the absence of a surrogate has resulted in conservative AI limits in some cases, posing practical challenges for impurity control. Therefore, a new framework for determining recommended AI limits was urgently needed. Here, the Carcinogenic Potency Categorization Approach (CPCA) and its supporting scientific rationale are presented. The CPCA is a rapidly-applied structure-activity relationship-based method that assigns a nitrosamine to 1 of 5 categories, each with a corresponding AI limit, reflecting predicted carcinogenic potency. The CPCA considers the number and distribution of α-hydrogens at the N-nitroso center and other activating and deactivating structural features of a nitrosamine that affect the α-hydroxylation metabolic activation pathway of carcinogenesis. The CPCA has been adopted internationally by several drug regulatory authorities as a simplified approach and a starting point to determine recommended AI limits for nitrosamines without the need for compound-specific empirical data.
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Affiliation(s)
- Naomi L Kruhlak
- US Food and Drug Administration (US FDA), Silver Spring, MD, USA.
| | | | - Roland Froetschl
- Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany
| | - Stefan Graber
- Swiss Agency for Therapeutic Products (Swissmedic), Bern, Switzerland
| | - Bodo Haas
- Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany
| | - Irene Horne
- Therapeutic Goods Administration (TGA), Canberra, Australia
| | - Stephen Horne
- Pharmaceutical Drugs Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Sruthi T King
- US Food and Drug Administration (US FDA), Silver Spring, MD, USA
| | - Iryna A Koval
- Medicines Evaluation Board (MEB), Utrecht, Netherlands
| | | | - Anja Langenkamp
- Swiss Agency for Therapeutic Products (Swissmedic), Bern, Switzerland
| | | | - Tyler Peryea
- US Food and Drug Administration (US FDA), Silver Spring, MD, USA
| | - Alan Sanh
- French National Agency for Medicines and Health Products Safety (ANSM), Saint-Denis, France
| | | | | | - Alisa Vespa
- Pharmaceutical Drugs Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Rhys Whomsley
- European Medicines Agency (EMA), Amsterdam, Netherlands
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Zingué S, Tchoupang EN, Madji LT, Pehuie Fomat BH, Mafogang B, Njamen D, Mendimi JMN. Ricinodendron heudelotii (Euphorbiaceae) seed oil prevents DMBA-induced breast cancer under menopause-like conditions in Wistar rats. Front Pharmacol 2024; 15:1389976. [PMID: 38818375 PMCID: PMC11137180 DOI: 10.3389/fphar.2024.1389976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 04/18/2024] [Indexed: 06/01/2024] Open
Abstract
Despite efforts, breast cancer remains associated with a high incidence and mortality rate. Ricinodendron heudelotii also known as "Njansang," is a plant used for cancer treatment. While several reports on the anticancer potential of its leaves exist, little is known about its seed oil. This study aimed to evaluate the in vitro and in vivo anti-breast cancer activity of "Njansang" seed oil. The inhibitory effect of "Njansang" seed oil was determined using MTT and CCK-8 dye reduction assays. Breast cancer was induced with DMBA and promoted with E2V (1 mg/kg) for 4 weeks in ovariectomized rats (menopausal condition). Evaluated parameters included tumor incidence, tumor mass and volume, histopathology, breast cancer biomarker CA 15-3, antioxidant status (CAT, GSH, MDA, NO, SOD), TNF-α and INFγ levels, lipid profile (total cholesterol, LDL-cholesterol, triglycerides and HDL-cholesterol), as well as toxicity parameters (ALT, AST, creatinine). "Njansang" oil significantly reduced the growth of ER+ (MCF-7) and triple negative (MDA-MB 231) adenocarcinoma cells in vitro as well as tumor incidence, tumor mass and CA 15-3 levels in vivo. It exhibited antioxidant activity, characterized by an increase in SOD and catalase activities, GSH levels and decreased MDA levels compared to the DMBA group. TNF-α and INF-γ levels were reduced following oil treatment, while total cholesterol, LDL-cholesterol and triglyceride levels were reduced. The aforementioned findings confirm the protective effects of "Njansang" oil on induced breast cancer in ovariectomized rats.
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Affiliation(s)
- Stéphane Zingué
- Department of Pharmacotoxicology and Pharmacokinetics, Faculty of Medicine and Biomedical Sciences, University of Yaounde 1, Yaounde, Cameroon
- Department of Medical and Biomedical Engineering, Higher Technical Teachers’ Training College, University of Ebolowa, Ebolowa, Cameroon
| | - Edwige Nana Tchoupang
- Department of Animal Science, Faculty of Agriculture and Veterinary Medicine, University of Buea, Buea, Cameroon
| | - Linda Takou Madji
- Department of Medical and Biomedical Engineering, Higher Technical Teachers’ Training College, University of Ebolowa, Ebolowa, Cameroon
| | - Boris Hugor Pehuie Fomat
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaounde, Cameroon
| | - Borelle Mafogang
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaounde, Cameroon
| | - Dieudonné Njamen
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaounde, Cameroon
| | - Joseph Marie Nkodo Mendimi
- Department of Morphological Sciences and Pathological Anatomy, Faculty of Medicine and Biomedical Sciences, University of Yaounde 1, Yaounde, Cameroon
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6
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Vikram HP, Kumar TP, Kumar G, Beeraka NM, Deka R, Suhail SM, Jat S, Bannimath N, Padmanabhan G, Chandan RS, Kumar P, Gurupadayya B. Nitrosamines crisis in pharmaceuticals - Insights on toxicological implications, root causes and risk assessment: A systematic review. J Pharm Anal 2024; 14:100919. [PMID: 38799236 PMCID: PMC11126534 DOI: 10.1016/j.jpha.2023.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 12/02/2023] [Accepted: 12/08/2023] [Indexed: 05/29/2024] Open
Abstract
The presence of N-nitroso compounds, particularly N-nitrosamines, in pharmaceutical products has raised global safety concerns due to their significant genotoxic and mutagenic effects. This systematic review investigates their toxicity in active pharmaceutical ingredients (APIs), drug products, and pharmaceutical excipients, along with novel analytical strategies for detection, root cause analysis, reformulation strategies, and regulatory guidelines for nitrosamines. This review emphasizes the molecular toxicity of N-nitroso compounds, focusing on genotoxic, mutagenic, carcinogenic, and other physiological effects. Additionally, it addresses the ongoing nitrosamine crisis, the development of nitrosamine-free products, and the importance of sensitive detection methods and precise risk evaluation. This comprehensive overview will aid molecular biologists, analytical scientists, formulation scientists in research and development sector, and researchers involved in management of nitrosamine-induced toxicity and promoting safer pharmaceutical products.
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Affiliation(s)
- Hemanth P.R. Vikram
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy Mysuru, JSS Academy of Higher Education and Research (JSSAHER), Mysuru, 570015, India
- Xenone Healthcare Pvt. Ltd., New Delhi, 110076, India
| | - Tegginamath Pramod Kumar
- Department of Pharmaceutics, JSS College of Pharmacy Mysuru, JSS Academy of Higher Education and Research (JSSAHER), Mysuru, 570015, India
| | - Gunjan Kumar
- Xenone Healthcare Pvt. Ltd., New Delhi, 110076, India
| | - Narasimha M. Beeraka
- Department of Human Anatomy, I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, 119991, Russian Federation
- Department of Pharmacology, Raghavendra Institute of Pharmaceutical Education and Research (RIPER), Ananthapuramu, 515721, India
- Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Rajashree Deka
- Animal Physiology and Biochemistry Laboratory, Department of Zoology, Gauhati University, Guwahati, 781014, India
| | - Sheik Mohammed Suhail
- Department of Pharmacology, JSS College of Pharmacy Mysuru, JSS Academy of Higher Education and Research (JSSAHER), Mysuru, 570015, India
| | - Sandeep Jat
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER)-Guwahati, Changsari, 781101, India
| | - Namitha Bannimath
- Department of Pharmacology, University of Galway, Galway, H91 TK33, Ireland
| | - Gayatiri Padmanabhan
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy Mysuru, JSS Academy of Higher Education and Research (JSSAHER), Mysuru, 570015, India
| | - Ravandur S. Chandan
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy Mysuru, JSS Academy of Higher Education and Research (JSSAHER), Mysuru, 570015, India
| | - Pramod Kumar
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER)-Guwahati, Changsari, 781101, India
| | - Bannimath Gurupadayya
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy Mysuru, JSS Academy of Higher Education and Research (JSSAHER), Mysuru, 570015, India
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7
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Ye Q, Geng X, Jiang H, Qin C, Wu H, Wang S, Wen H. Genotoxicity assessments of N-nitrosoethylisopropylamine (NEIPA) and N-nitrosodiisopropylamine (NDIPA) in the C57BL/6J mouse. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2024; 896:503763. [PMID: 38821676 DOI: 10.1016/j.mrgentox.2024.503763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 04/26/2024] [Accepted: 04/27/2024] [Indexed: 06/02/2024]
Abstract
N-Nitrosamines, known as drug impurities and suspected carcinogens, have drawn significant public concern. In response to drug regulatory needs, the European Medicines Agency (EMA) has previously proposed a carcinogenic potency categorization approach based on the N-nitrosamine α-hydroxylation hypothesis, i.e., that N-nitrosamine mutagenicity increases with the number of α-hydrogen atoms. However, this structure-activity relationship has not been fully tested in vivo. NEIPA (N-nitrosoethylisopropylamine) and NDIPA (N-nitrosodiisopropylamine) are small N-Nitrosamines with similar structures, differing in that the former compound has an additional α-hydrogen atom. In this study, NEIPA and NEIPA doses, 25-100 mg/kg, were administered orally to C57BL/6 J mice for seven consecutive days, and their mutation and DNA damage effects were compared. Compared with NDIPA, the mutagenicity and DNA damage potencies of NEIPA (which contains one more α-hydrogen) were much greater. These differences may be related to their distinct metabolic pathways and target organs. This case study confirms the role of α-hydroxyl modification in the mutagenicity of nitrosamines, with oxidation at the α-hydrogen being a crucial step in the formation of mutagens from N-Nitrosamines, and can inform mutagenicity risk assessment and the formulation of regulatory standards for N-nitrosamine impurities.
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Affiliation(s)
- Qian Ye
- China Pharmaceutical University, Nanjing 211198, PR China
| | - Xingchao Geng
- National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Key Laboratory of Beijing for Nonclinical Safety Evaluation Research of Drugs, Beijing 100176, PR China
| | - Hua Jiang
- National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Key Laboratory of Beijing for Nonclinical Safety Evaluation Research of Drugs, Beijing 100176, PR China
| | - Chao Qin
- National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Key Laboratory of Beijing for Nonclinical Safety Evaluation Research of Drugs, Beijing 100176, PR China
| | - Hui Wu
- China Pharmaceutical University, Nanjing 211198, PR China; National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Key Laboratory of Beijing for Nonclinical Safety Evaluation Research of Drugs, Beijing 100176, PR China
| | - Sanlong Wang
- National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Key Laboratory of Beijing for Nonclinical Safety Evaluation Research of Drugs, Beijing 100176, PR China
| | - Hairuo Wen
- National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Key Laboratory of Beijing for Nonclinical Safety Evaluation Research of Drugs, Beijing 100176, PR China.
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8
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Thomas DN, Wills JW, Tracey H, Baldwin SJ, Burman M, Williams AN, Harte DSG, Buckley RA, Lynch AM. Ames test study designs for nitrosamine mutagenicity testing: qualitative and quantitative analysis of key assay parameters. Mutagenesis 2024; 39:78-95. [PMID: 38112628 DOI: 10.1093/mutage/gead033] [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: 08/31/2023] [Accepted: 12/15/2023] [Indexed: 12/21/2023] Open
Abstract
The robust control of genotoxic N-nitrosamine (NA) impurities is an important safety consideration for the pharmaceutical industry, especially considering recent drug product withdrawals. NAs belong to the 'cohort of concern' list of genotoxic impurities (ICH M7) because of the mutagenic and carcinogenic potency of this chemical class. In addition, regulatory concerns exist regarding the capacity of the Ames test to predict the carcinogenic potential of NAs because of historically discordant results. The reasons postulated to explain these discordant data generally point to aspects of Ames test study design. These include vehicle solvent choice, liver S9 species, bacterial strain, compound concentration, and use of pre-incubation versus plate incorporation methods. Many of these concerns have their roots in historical data generated prior to the harmonization of Ames test guidelines. Therefore, we investigated various Ames test assay parameters and used qualitative analysis and quantitative benchmark dose modelling to identify which combinations provided the most sensitive conditions in terms of mutagenic potency. Two alkyl-nitrosamines, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) were studied. NDMA and NDEA mutagenicity was readily detected in the Ames test and key assay parameters were identified that contributed to assay sensitivity rankings. The pre-incubation method (30-min incubation), appropriate vehicle (water or methanol), and hamster-induced liver S9, alongside Salmonella typhimurium strains TA100 and TA1535 and Escherichia coli strain WP2uvrA(pKM101) provide the most sensitive combination of assay parameters in terms of NDMA and NDEA mutagenic potency in the Ames test. Using these parameters and further quantitative benchmark dose modelling, we show that N-nitrosomethylethylamine (NMEA) is positive in Ames test and therefore should no longer be considered a historically discordant NA. The results presented herein define a sensitive Ames test design that can be deployed for the assessment of NAs to support robust impurity qualifications.
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Affiliation(s)
- Dean N Thomas
- GSK Research & Development, Genetic Toxicology and Photosafety, Stevenage SG1 2NY, United Kingdom
| | - John W Wills
- GSK Research & Development, Genetic Toxicology and Photosafety, Stevenage SG1 2NY, United Kingdom
| | - Helen Tracey
- GSK Research & Development, Genetic Toxicology and Photosafety, Stevenage SG1 2NY, United Kingdom
| | - Sandy J Baldwin
- GSK Research & Development, Genetic Toxicology and Photosafety, Stevenage SG1 2NY, United Kingdom
| | - Mark Burman
- GSK Research & Development, Genetic Toxicology and Photosafety, Stevenage SG1 2NY, United Kingdom
| | - Abbie N Williams
- GSK Research & Development, Genetic Toxicology and Photosafety, Stevenage SG1 2NY, United Kingdom
| | - Danielle S G Harte
- GSK Research & Development, Genetic Toxicology and Photosafety, Stevenage SG1 2NY, United Kingdom
| | - Ruby A Buckley
- GSK Research & Development, Genetic Toxicology and Photosafety, Stevenage SG1 2NY, United Kingdom
| | - Anthony M Lynch
- GSK Research & Development, Genetic Toxicology and Photosafety, Stevenage SG1 2NY, United Kingdom
- School of Medicine, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
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9
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Snodin DJ, Trejo-Martin A, Ponting DJ, Smith GF, Czich A, Cross K, Custer L, Elloway J, Greene N, Kalgutkar AS, Stalford SA, Tennant RE, Vock E, Zalewski A, Ziegler V, Dobo KL. Mechanisms of Nitrosamine Mutagenicity and Their Relationship to Rodent Carcinogenic Potency. Chem Res Toxicol 2024; 37:181-198. [PMID: 38316048 DOI: 10.1021/acs.chemrestox.3c00327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
A thorough literature review was undertaken to understand how the pathways of N-nitrosamine transformation relate to mutagenic potential and carcinogenic potency in rodents. Empirical and computational evidence indicates that a common radical intermediate is created by CYP-mediated hydrogen abstraction at the α-carbon; it is responsible for both activation, leading to the formation of DNA-reactive diazonium species, and deactivation by denitrosation. There are competing sites of CYP metabolism (e.g., β-carbon), and other reactive species can form following initial bioactivation, although these alternative pathways tend to decrease rather than enhance carcinogenic potency. The activation pathway, oxidative dealkylation, is a common reaction in drug metabolism and evidence indicates that the carbonyl byproduct, e.g., formaldehyde, does not contribute to the toxic properties of N-nitrosamines. Nitric oxide (NO), a side product of denitrosation, can similarly be discounted as an enhancer of N-nitrosamine toxicity based on carcinogenicity data for substances that act as NO-donors. However, not all N-nitrosamines are potent rodent carcinogens. In a significant number of cases, there is a potency overlap with non-N-nitrosamine carcinogens that are not in the Cohort of Concern (CoC; high-potency rodent carcinogens comprising aflatoxin-like-, N-nitroso-, and alkyl-azoxy compounds), while other N-nitrosamines are devoid of carcinogenic potential. In this context, mutagenicity is a useful surrogate for carcinogenicity, as proposed in the ICH M7 (R2) (2023) guidance. Thus, in the safety assessment and control of N-nitrosamines in medicines, it is important to understand those complementary attributes of mechanisms of mutagenicity and structure-activity relationships that translate to elevated potency versus those which are associated with a reduction in, or absence of, carcinogenic potency.
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Affiliation(s)
| | - Alejandra Trejo-Martin
- Gilead Sciences Inc. Nonclinical Safety and Pathobiology (NSP), Foster City, California 94404, United States
| | | | - Graham F Smith
- AstraZeneca, Imaging and Data Analytics, Clinical Pharmacology and Safety Sciences, Research and Development, CB2 0AA Cambridge, U.K
| | - Andreas Czich
- Sanofi, Research and Development, Preclinical Safety, 65926 Frankfurt, Germany
| | - Kevin Cross
- Instem, Conshohocken, Pennsylvania 19428, United States
| | - Laura Custer
- Bristol-Myers Squibb, Nonclinical Safety, New Brunswick, New Jersey 08903, United States
| | - Joanne Elloway
- AstraZeneca, Safety Sciences, Clinical Pharmacology and Safety Sciences Research and Development, CB2 0AA Cambridge, U.K
| | - Nigel Greene
- AstraZeneca, Imaging and Data Analytics, Clinical Pharmacology and Safety Sciences, Research and Development, Waltham, Massachusetts 02451, United States
| | - Amit S Kalgutkar
- Medicine Design, Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | | | | | - Esther Vock
- Boehringer-Ingelheim Pharma GmbH & Co., KG, 88397 Biberach an der Riss, Germany
| | - Adam Zalewski
- Bayer AG, Pharmaceuticals, Genetic and Computational Toxicology, 13342 Berlin, Germany
| | - Verena Ziegler
- Bayer AG, Pharmaceuticals, Genetic and Computational Toxicology, 13342 Berlin, Germany
| | - Krista L Dobo
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
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10
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Nomura-Komoike K, Nishino R, Fujieda H. Effects of different alkylating agents on photoreceptor degeneration and proliferative response of Müller glia. Sci Rep 2024; 14:61. [PMID: 38167441 PMCID: PMC10762013 DOI: 10.1038/s41598-023-50485-7] [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: 09/13/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024] Open
Abstract
Animal models for retinal degeneration are essential for elucidating its pathogenesis and developing new therapeutic strategies in humans. N-methyl-N-nitrosourea (MNU) has been extensively used to construct a photoreceptor-specific degeneration model, which has served to unveil the molecular process of photoreceptor degeneration as well as the mechanisms regulating the protective responses of remaining cells. Methyl methanesulphonate (MMS), also known to cause photoreceptor degeneration, is considered a good alternative to MNU due to its higher usability; however, detailed pathophysiological processes after MMS treatment remain uncharacterized. Here, we analyzed the time course of photoreceptor degeneration, Müller glial proliferation, and expression of secretory factors after MNU and MMS treatments in rats. While the timing of rod degeneration was similar between the treatments, we unexpectedly found that cones survived slightly longer after MMS treatment. Müller glia reentered the cell cycle at a similar timing after the two treatments; however, the G1/S transition occurred earlier after MMS treatment. Moreover, growth factors such as FGF2 and LIF were more highly upregulated in the MMS model. These data suggest that comparative analyses of the two injury models may be beneficial for understanding the complex regulatory mechanisms underlying the proliferative response of Müller glia.
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Affiliation(s)
- Kaori Nomura-Komoike
- Department of Anatomy and Neurobiology, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Reiko Nishino
- Department of Anatomy and Neurobiology, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
- Department of Ophthalmology, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Hiroki Fujieda
- Department of Anatomy and Neurobiology, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
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11
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Felter SP, Ponting DJ, Mudd AM, Thomas R, Oliveira AAF. Maximizing use of existing carcinogenicity data to support acceptable intake levels for mutagenic impurities in pharmaceuticals: Learnings from N-nitrosamine case studies. Regul Toxicol Pharmacol 2023; 143:105459. [PMID: 37474097 DOI: 10.1016/j.yrtph.2023.105459] [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: 04/27/2023] [Revised: 06/27/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
The unexpected finding of N-nitrosamine (NA) impurities in many pharmaceutical products raised significant challenges for industry and regulators. In addition to well-studied small molecular weight NAs, many of which are potent rodent carcinogens, novel NAs associated with active pharmaceutical ingredients have been found, many of which have limited or no safety data. A tiered approach to establishing Acceptable Intake (AI) limits for NA impurities has been established using chemical-specific data, read-across, or a class-specific TTC limit. There are ∼140 NAs with some rodent carcinogenicity data, but much of it is older and does not meet current guidelines for what constitutes a 'robust' bioassay. Nevertheless, these data are an important source of information to ensure the best science is used for assessing NA impurities and assuring consumer safety while minimizing impact that can lead to drug shortages. We present several strategies to maximize the use of imperfect data including using a lower confidence limit on a rodent TD50, and leveraging data from multiple NAs. Information on the chemical structure known to impact potency can also support development of an AI or potentially conclude that a particular NA does not fall in the cohort of concern for potent carcinogenicity.
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Affiliation(s)
- S P Felter
- Procter & Gamble, Central Product Safety, 8700 Mason-Montgomery Rd, Mason, OH, USA.
| | - D J Ponting
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, LS11 5PS, UK
| | - A M Mudd
- Procter & Gamble, Central Product Safety, 8700 Mason-Montgomery Rd, Mason, OH, USA
| | - R Thomas
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, LS11 5PS, UK
| | - A A F Oliveira
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, LS11 5PS, UK
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12
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Tennant RE, Ponting DJ, Thresher A. A deep dive into historical Ames study data for N-nitrosamine compounds. Regul Toxicol Pharmacol 2023; 143:105460. [PMID: 37495012 DOI: 10.1016/j.yrtph.2023.105460] [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: 03/29/2023] [Revised: 06/09/2023] [Accepted: 07/19/2023] [Indexed: 07/28/2023]
Abstract
Mutagenicity data is a core component of the safety assessment data required by regulatory agencies for acceptance of new drug compounds, with the OECD-471 bacterial reverse mutation (Ames) assay most widely used as a primary screen to assess drug impurities for potential mutagenic risk. N-Nitrosamines are highly potent mutagenic carcinogens in rodent bioassays and their recent detection as impurities in pharmaceutical products has sparked increased interest in their safety assessment. Previous literature reports indicated that the Ames test might not be sensitive enough to detect the mutagenic potential of N-nitrosamines in order to accurately predict a risk of carcinogenicity. To explore this hypothesis, public Ames and rodent carcinogenicity data pertaining to the N-nitrosamine class of compounds was collated for analysis. Here we present how variations to the OECD 471-compliant Ames test, including strain, metabolic activation, solvent type and pre-incubation/plate incorporation methods, may impact the predictive performance for carcinogenicity. An understanding of optimal conditions for testing of N-nitrosamines may improve both the accuracy and confidence in the ability of the Ames test to identify potential carcinogens.
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Affiliation(s)
- Rachael E Tennant
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, West Yorkshire, LS11 5PS, UK.
| | - David J Ponting
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, West Yorkshire, LS11 5PS, UK
| | - Andrew Thresher
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, West Yorkshire, LS11 5PS, UK
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13
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Fotsing SI, Ngo Pambe JC, Silihe KK, Yembeau NL, Choupo A, Njamen D, Pieme CA, Zingue S. Breast cancer cell growth arrest and chemopreventive effects of Passiflora edulis Sims (Passifloraceae) ethanolic leaves extract on a rat model of mammary carcinoma. JOURNAL OF ETHNOPHARMACOLOGY 2023; 311:116408. [PMID: 36966851 DOI: 10.1016/j.jep.2023.116408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 03/10/2023] [Accepted: 03/19/2023] [Indexed: 06/18/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Despite various prevention and treatment measures, the incidence and mortality due to breast cancer has been increasing globally. Passiflora edulis Sims is a plant used for the treatment of various diseases in traditional medicine, including cancers. AIM OF THE STUDY To assess the anti-breast cancer activity of the ethanolic extract of P. edulis leaves in vitro and in vivo. MATERIAL AND METHODS In vitro, the cell growth and proliferation were determined based on the MTT and BrdU assays. The flow cytometry was used to analyze the cell death mechanism while, cell migration, cell adhesion and chemotaxis were assayed for anti-metastatic potential. In vivo, 56 female Wistar rats aged 45-50 days (∼75 g) were exposed to 7,12-dimethylbenz(a)anthracene-DMBA except the normal group. Negative control group (DMBA) received solvent dilution throughout the study; standards groups (tamoxifen - 3.3 mg/kg BW and letrozole - 1 mg/kg BW) as well as P. edulis leaves ethanolic extract groups (50, 100 and 200 mg/kg) treated for 20 weeks. Tumor incidence, tumor burden and volume, CA 15-3 serum' level, antioxidant, inflammatory status and histopathology were assessed. RESULTS P. edulis extract showed a significant and concentration-dependent inhibition of MCF-7 and MDA-MB 231 cells growth at 100 μg/mL. It inhibited cell proliferation and clones' formation and induced apoptosis in MDA-MB 231 cells. The migration of cell into the zone freed of cells and the number of invading cells after the 48 and 72 h were significantly diminished while, it increased their adherence to collagen and fibronectin extracellular matrix as does Doxorubicin. In vivo, all rats in the DMBA group exhibited a significant (p < 0.001) increase in tumor volume, tumor burden and grade (adenocarcinoma of SBR III) and pro-inflammatory cytokine levels (TNF-α, INF-γ, IL-6 and IL-12). P. edulis extract at all tested doses significantly inhibited the DMBA-induced increase in tumor incidence, tumor burden and grade (SBR I) as well as pro-inflammatory cytokines. Moreover, it increased enzymatic and non-enzymatic antioxidants (SOD, catalase, and GSH) and decreased MDA levels although a greater effect was observed with Tamoxifen and Letrozole. P. edulis has medium content on polyphenols, flavonoids and tannins. CONCLUSION P. edulis has chemo-preventive effects against DMBA-induced breast cancer in rats probably through its antioxidative, anti-inflammatory and apoptosis-inducing potentials.
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Affiliation(s)
- Sorelle Ines Fotsing
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon.
| | - Judith Christiane Ngo Pambe
- Department of Morphological Sciences and Pathological Anatomy, Faculty of Medicine and Biomedical Sciences, University of Garoua, P.O. Box 317, Garoua, Cameroon.
| | - Kevine Kamga Silihe
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon; Department of Pharmacotoxicology and Pharmacokinetics, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, P.O. Box 1364, Yaoundé, Cameroon.
| | - Natacha Lena Yembeau
- Department of Biochemistry and Physiological Sciences, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, P.O. Box 1364, Yaoundé, Cameroon.
| | - Armand Choupo
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon.
| | - Dieudonné Njamen
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon.
| | - Constant Anatole Pieme
- Department of Biochemistry and Physiological Sciences, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, P.O. Box 1364, Yaoundé, Cameroon.
| | - Stéphane Zingue
- Department of Pharmacotoxicology and Pharmacokinetics, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, P.O. Box 1364, Yaoundé, Cameroon.
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14
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Bercu JP, Masuda-Herrera M, Trejo-Martin A, Sura P, Jolly R, Kenyon M, Thomas R, Ponting DJ, Snodin D, Tuschl G, Simon S, De Vlieger K, Hutchinson R, Czich A, Glowienke S, Reddy MV, Johanssen S, Vock E, Claude N, Weaver RJ. Acceptable Intakes (AIs) for 11 Small molecule N-nitrosamines (NAs). Regul Toxicol Pharmacol 2023:105415. [PMID: 37257751 DOI: 10.1016/j.yrtph.2023.105415] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/21/2023] [Accepted: 05/07/2023] [Indexed: 06/02/2023]
Abstract
Low levels of N-nitrosamines (NAs) were detected in pharmaceuticals and, as a result, health authorities (HAs) have published acceptable intakes (AIs) in pharmaceuticals to limit potential carcinogenic risk. The rationales behind the AIs have not been provided to understand the process for selecting a TD50 or read-across analog. In this manuscript we evaluated the toxicity data for eleven common NAs in a comprehensive and transparent process consistent with ICH M7. This evaluation included substances which had datasets that were robust, limited but sufficient, and substances with insufficient experimental animal carcinogenicity data. In the case of robust or limited but sufficient carcinogenicity information, AIs were calculated based on published or derived TD50s from the most sensitive organ site. In the case of insufficient carcinogenicity information, available carcinogenicity data and structure activity relationships (SARs) were applied to categorical-based AIs of 1500 ng/day, 150 ng/day or 18 ng/day; however additional data (such as biological or additional computational modelling) could inform an alternative AI. This approach advances the methodology used to derive AIs for NAs.
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Affiliation(s)
- Joel P Bercu
- Gilead Sciences, Inc., Nonclinical Safety and Pathobiology (NSP), Foster City, CA, USA.
| | - Melisa Masuda-Herrera
- Gilead Sciences, Inc., Nonclinical Safety and Pathobiology (NSP), Foster City, CA, USA
| | | | - Priyanka Sura
- Gilead Sciences, Inc., Nonclinical Safety and Pathobiology (NSP), Foster City, CA, USA
| | | | - Michelle Kenyon
- Pfizer Worldwide Research, Development and Medical, Drug Safety Research and Development, Eastern Point Road, Groton, CT, USA
| | - Rob Thomas
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, UK
| | - David J Ponting
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, UK
| | | | - Gregor Tuschl
- Merck KGaA, Global Chemical and Preclinical Safety, Darmstadt, Germany
| | - Stephanie Simon
- Merck KGaA, Global Chemical and Preclinical Safety, Darmstadt, Germany
| | | | | | | | | | | | - Sandra Johanssen
- Bayer AG, Pharmaceuticals, Research & Development, Berlin, Germany
| | - Esther Vock
- Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Str., Biberach an der Riss, Germany
| | - Nancy Claude
- Servier Paris-Saclay R&D Institute, Gif-sur-Yvette, France
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15
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Snodin DJ. Mutagenic impurities in pharmaceuticals: A critical assessment of the cohort of concern with a focus on N-nitrosamines. Regul Toxicol Pharmacol 2023; 141:105403. [PMID: 37116739 DOI: 10.1016/j.yrtph.2023.105403] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/20/2023] [Accepted: 04/25/2023] [Indexed: 04/30/2023]
Abstract
The TTC (Threshold of Toxicological Concern; set at 1.5 μg/day for pharmaceuticals) defines an acceptable patient intake for any unstudied chemical posing a negligible risk of carcinogenicity or other toxic effects. A group of high potency mutagenic carcinogens, defined solely by the presence of particular structural alerts, are referred to as the "cohort of concern" (CoC); aflatoxin-like-, N-nitroso-, and alkyl-azoxy compounds are considered to pose a significant carcinogenic risk at intakes below the TTC. Kroes et al.2004, derived values for the TTC and CoC in the context of food components, employing a non-transparent dataset never placed in the public domain. Using a reconstructed all-carcinogen dataset from relevant publications, it is now clear that there are exceptions for all three CoC structural classes. N-Nitrosamines represent 62% of the N-nitroso class in the reconstructed dataset. Employing a contemporary dataset, 20% are negative in rodent carcinogenicity bioassays with less than 50% of N-nitrosamines estimated to fall into the highest risk category. It is recommended that CoC nitrosamines are identified by compound-specific data rather than structural alerts. Thus, it should be possible to distinguish CoC from non-CoC N-nitrosamines in the context of mutagenic impurities described in ICH M7 (R1).
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Affiliation(s)
- David J Snodin
- Xiphora Biopharma Consulting, 9 Richmond Apartments, Redland Court Road, Bristol, BS6 7BG, UK.
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16
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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Hogstrand C, (Ron) Hoogenboom L, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Vleminckx C, Wallace H, Romualdo B, Cristina F, Stephen H, Marco I, Mosbach‐Schulz O, Riolo F, Christodoulidou A, Grasl‐Kraupp B. Risk assessment of N-nitrosamines in food. EFSA J 2023; 21:e07884. [PMID: 36999063 PMCID: PMC10043641 DOI: 10.2903/j.efsa.2023.7884] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023] Open
Abstract
EFSA was asked for a scientific opinion on the risks to public health related to the presence of N-nitrosamines (N-NAs) in food. The risk assessment was confined to those 10 carcinogenic N-NAs occurring in food (TCNAs), i.e. NDMA, NMEA, NDEA, NDPA, NDBA, NMA, NSAR, NMOR, NPIP and NPYR. N-NAs are genotoxic and induce liver tumours in rodents. The in vivo data available to derive potency factors are limited, and therefore, equal potency of TCNAs was assumed. The lower confidence limit of the benchmark dose at 10% (BMDL10) was 10 μg/kg body weight (bw) per day, derived from the incidence of rat liver tumours (benign and malignant) induced by NDEA and used in a margin of exposure (MOE) approach. Analytical results on the occurrence of N-NAs were extracted from the EFSA occurrence database (n = 2,817) and the literature (n = 4,003). Occurrence data were available for five food categories across TCNAs. Dietary exposure was assessed for two scenarios, excluding (scenario 1) and including (scenario 2) cooked unprocessed meat and fish. TCNAs exposure ranged from 0 to 208.9 ng/kg bw per day across surveys, age groups and scenarios. 'Meat and meat products' is the main food category contributing to TCNA exposure. MOEs ranged from 3,337 to 48 at the P95 exposure excluding some infant surveys with P95 exposure equal to zero. Two major uncertainties were (i) the high number of left censored data and (ii) the lack of data on important food categories. The CONTAM Panel concluded that the MOE for TCNAs at the P95 exposure is highly likely (98-100% certain) to be less than 10,000 for all age groups, which raises a health concern.
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17
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Fahrer J, Christmann M. DNA Alkylation Damage by Nitrosamines and Relevant DNA Repair Pathways. Int J Mol Sci 2023; 24:ijms24054684. [PMID: 36902118 PMCID: PMC10003415 DOI: 10.3390/ijms24054684] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/17/2023] [Accepted: 02/24/2023] [Indexed: 03/04/2023] Open
Abstract
Nitrosamines occur widespread in food, drinking water, cosmetics, as well as tobacco smoke and can arise endogenously. More recently, nitrosamines have been detected as impurities in various drugs. This is of particular concern as nitrosamines are alkylating agents that are genotoxic and carcinogenic. We first summarize the current knowledge on the different sources and chemical nature of alkylating agents with a focus on relevant nitrosamines. Subsequently, we present the major DNA alkylation adducts induced by nitrosamines upon their metabolic activation by CYP450 monooxygenases. We then describe the DNA repair pathways engaged by the various DNA alkylation adducts, which include base excision repair, direct damage reversal by MGMT and ALKBH, as well as nucleotide excision repair. Their roles in the protection against the genotoxic and carcinogenic effects of nitrosamines are highlighted. Finally, we address DNA translesion synthesis as a DNA damage tolerance mechanism relevant to DNA alkylation adducts.
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Affiliation(s)
- Jörg Fahrer
- Division of Food Chemistry and Toxicology, Department of Chemistry, RPTU Kaiserslautern-Landau, Erwin-Schrödinger Strasse 52, D-67663 Kaiserslautern, Germany
- Correspondence: (J.F.); (M.C.); Tel.: +496312052974 (J.F.); Tel: +496131179066 (M.C.)
| | - Markus Christmann
- Department of Toxicology, University Medical Center Mainz, Obere Zahlbacher Strasse 67, D-55131 Mainz, Germany
- Correspondence: (J.F.); (M.C.); Tel.: +496312052974 (J.F.); Tel: +496131179066 (M.C.)
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18
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Horne S, Vera MD, Nagavelli LR, Sayeed VA, Heckman L, Johnson D, Berger D, Yip YY, Krahn CL, Sizukusa LO, Rocha NFM, Bream RN, Ludwig J, Keire DA, Condran G. Regulatory Experiences with Root Causes and Risk Factors for Nitrosamine Impurities in Pharmaceuticals. J Pharm Sci 2023; 112:1166-1182. [PMID: 36599405 DOI: 10.1016/j.xphs.2022.12.022] [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: 11/01/2022] [Revised: 12/19/2022] [Accepted: 12/23/2022] [Indexed: 01/02/2023]
Abstract
N-Nitrosamines (also referred to as nitrosamines) are a class of substances, many of which are highly potent mutagenic agents which have been classified as probable human carcinogens. Nitrosamine impurities have been a concern within the pharmaceutical industry and by regulatory authorities worldwide since June 2018, when regulators were informed of the presence of N-nitrosodimethylamine (NDMA) in the angiotensin-II receptor blocker (ARB) medicine, valsartan. Since that time, regulatory authorities have collaborated to share information and knowledge on issues related to nitrosamines with a goal of promoting convergence on technical issues and reducing and mitigating patient exposure to harmful nitrosamine impurities in human drug products. This paper shares current scientific information from a quality perspective on risk factors and potential root causes for nitrosamine impurities, as well as recommendations for risk mitigation and control strategies.
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Affiliation(s)
| | - Matthew D Vera
- US Food and Drug Administration (US FDA), Silver Spring, MD, 20993, USA
| | - Laxma R Nagavelli
- US Food and Drug Administration (US FDA), Silver Spring, MD, 20993, USA
| | - Vilayat A Sayeed
- US Food and Drug Administration (US FDA), Silver Spring, MD, 20993, USA
| | - Laurel Heckman
- US Food and Drug Administration (US FDA), Silver Spring, MD, 20993, USA
| | - Deborah Johnson
- US Food and Drug Administration (US FDA), Silver Spring, MD, 20993, USA
| | - Dan Berger
- US Food and Drug Administration (US FDA), Silver Spring, MD, 20993, USA
| | | | | | | | | | - Robert N Bream
- European Medicines Agency (EMA, EU), Amsterdam, the Netherlands
| | - Joachim Ludwig
- Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM), Bonn, Germany
| | - David A Keire
- US Food and Drug Administration (US FDA), St Louis, MO, 63110, USA
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19
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Rietjens IMCM, Michael A, Bolt HM, Siméon B, Andrea H, Nils H, Christine K, Angela M, Gloria P, Daniel R, Natalie T, Gerhard E. The role of endogenous versus exogenous sources in the exposome of putative genotoxins and consequences for risk assessment. Arch Toxicol 2022; 96:1297-1352. [PMID: 35249149 PMCID: PMC9013691 DOI: 10.1007/s00204-022-03242-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 02/01/2022] [Indexed: 12/21/2022]
Abstract
The "totality" of the human exposure is conceived to encompass life-associated endogenous and exogenous aggregate exposures. Process-related contaminants (PRCs) are not only formed in foods by heat processing, but also occur endogenously in the organism as physiological components of energy metabolism, potentially also generated by the human microbiome. To arrive at a comprehensive risk assessment, it is necessary to understand the contribution of in vivo background occurrence as compared to the ingestion from exogenous sources. Hence, this review provides an overview of the knowledge on the contribution of endogenous exposure to the overall exposure to putative genotoxic food contaminants, namely ethanol, acetaldehyde, formaldehyde, acrylamide, acrolein, α,β-unsaturated alkenals, glycation compounds, N-nitroso compounds, ethylene oxide, furans, 2- and 3-MCPD, and glycidyl esters. The evidence discussed herein allows to conclude that endogenous formation of some contaminants appears to contribute substantially to the exposome. This is of critical importance for risk assessment in the cases where endogenous exposure is suspected to outweigh the exogenous one (e.g. formaldehyde and acrolein).
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Affiliation(s)
- Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - Arand Michael
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstr. 190, 8057, Zurich, Switzerland
| | - Hermann M Bolt
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund (IfADo), Ardeystr. 67, 44139, Dortmund, Germany
| | | | - Hartwig Andrea
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany
| | - Hinrichsen Nils
- Food Oils and Fats Research, ADM Hamburg AG, Research, Seehafenstraße 24, 21079, Hamburg, Germany
| | - Kalisch Christine
- Department of Toxicology, University of Würzburg, Versbacher Straße 9, 97078, Wurzburg, Germany
| | - Mally Angela
- Department of Toxicology, University of Würzburg, Versbacher Straße 9, 97078, Wurzburg, Germany
| | - Pellegrino Gloria
- Scientific Affairs and Research, Luigi Lavazza SpA, Strada Settimo, 410, 10156, Turin, Italy
| | - Ribera Daniel
- Regulatory and Scientific Affairs EMEA, Cargill R&D, Havenstraat 84, 1800, Vivoorde, Belgium
| | - Thatcher Natalie
- Food Safety, Mondelez International, Bournville Lane, Birmingham, B30 2LU, UK
| | - Eisenbrand Gerhard
- Department of Toxicology and Food Chemistry, University of Kaiserslautern, Kühler Grund 48/1, 69126, Heidelberg, Germany
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20
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Li Y, Hecht SS. Metabolic Activation and DNA Interactions of Carcinogenic N-Nitrosamines to Which Humans Are Commonly Exposed. Int J Mol Sci 2022; 23:ijms23094559. [PMID: 35562949 PMCID: PMC9105260 DOI: 10.3390/ijms23094559] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 02/04/2023] Open
Abstract
Carcinogenic N-nitrosamine contamination in certain drugs has recently caused great concern and the attention of regulatory agencies. These carcinogens-widely detectable in relatively low levels in food, water, cosmetics, and drugs-are well-established and powerful animal carcinogens. The electrophiles resulting from the cytochrome P450-mediated metabolism of N-nitrosamines can readily react with DNA and form covalent addition products (DNA adducts) that play a central role in carcinogenesis if not repaired. In this review, we aim to provide a comprehensive and updated review of progress on the metabolic activation and DNA interactions of 10 carcinogenic N-nitrosamines to which humans are commonly exposed. Certain DNA adducts such as O6-methylguanine with established miscoding properties play central roles in the cancer induction process, whereas others have been linked to the high incidence of certain types of cancers. We hope the data summarized here will help researchers gain a better understanding of the bioactivation and DNA interactions of these 10 carcinogenic N-nitrosamines and facilitate further research on their toxicologic and carcinogenic properties.
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Affiliation(s)
- Yupeng Li
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
- Correspondence: ; Tel.: +1-612-624-8187
| | - Stephen S. Hecht
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
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21
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Bringezu F, Simon S. Salmonella typhimurium TA100 and TA1535 and E. coli WP2 uvrA are highly sensitive to detect the mutagenicity of short Alkyl-N-Nitrosamines in the Bacterial Reverse Mutation Test. Toxicol Rep 2022; 9:250-255. [PMID: 35198408 PMCID: PMC8850549 DOI: 10.1016/j.toxrep.2022.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 01/20/2022] [Accepted: 02/06/2022] [Indexed: 11/22/2022] Open
Abstract
Humans are exposed to low levels of N-nitrosamines via different sources. N-Nitrosamines have recently been detected as impurities in various marketed drugs and they are known mutagenic carcinogens belonging to the cohort of concern as referred to in the ICH M7 guideline. Despite their well-known mutagenic properties, there is ongoing discussion on the suitability of the bacterial reverse mutation assay and using induced rat liver S9 as the external source of metabolism to detect their mutagenic potential. Therefore, we have investigated the mutagenic potential of N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodipropylamine, and N-nitrosodibutylamine in vitro under various conditions. Our work showed that the bacterial reverse mutation assay applying plate incorporation or preincubation protocols and using Salmonella typhimurium strains TA100 and TA1535 and E. coli WP2 uvrA is suitable to predict the mutagenicity of n-nitrosamines in the presence of phenobarbital/β-naphthoflavone induced rat liver S9.
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22
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Developing Structure-Activity Relationships for N-Nitrosamine Activity. COMPUTATIONAL TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 20. [PMID: 34901581 DOI: 10.1016/j.comtox.2021.100186] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The detection of N-nitrosodimethylamine (NDMA) in several marketed drugs led regulatory agencies to require that N-nitrosamine risk assessments be performed on all marketed medical products [EMA/351053/2019 rev 1 (2019)]. Regulation of N-nitrosamine impurity levels in pharmaceutical drug substances and products is described in the ICH M7(R1) guideline where they are referred to as "cohort-of-concern" compounds as several are potent rodent carcinogens [Kroes et. al. 2004]. EMA, U.S. FDA and other regulatory agencies have set provisional acceptable daily intake limits for N-nitrosamines calculated from rodent carcinogenicity TD50 values for experimentally measured N-nitrosamines or the measured TD50 values of close analogs. The class-specific limit can be adjusted based upon a structure activity relationship analysis (SAR) and comparison with analogs having established carcinogenicity data [EMA/369136/2020, (2020)]. To investigate whether improvements in SARs can more accurately predict N-nitrosamine carcinogenic potency, an ad hoc workgroup of 23 companies and universities was established with the goals of addressing several scientific and regulatory issues including: reporting and review of N-nitrosamine mutagenicity and carcinogenicity reaction mechanisms, collection and review of available, public relevant experimental data, development of structure-activity relationships consistent with mechanisms for prediction of N-nitrosamine carcinogenic potency categories, and improved methods for calculating acceptable intake limits for N-nitrosamines based upon mechanistic analogs. Here we describe this collaboration and review our progress to date towards development of mechanistically based structure-activity relationships. We propose improving risk assessment of N-nitrosamines by first establishing the dominant reaction mechanism prior to retrieving an appropriate set of close analogs for use in read-across exercises.
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23
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Kostka T, Empl MT, Seiwert N, Geisen SM, Hoffmann P, Adam J, Seeger B, Shay JW, Christmann M, Sturla SJ, Fahrer J, Steinberg P. Repair of O6-carboxymethylguanine adducts by O6-methylguanine-DNA methyltransferase in human colon epithelial cells. Carcinogenesis 2021; 42:1110-1118. [PMID: 34115837 DOI: 10.1093/carcin/bgab049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/23/2021] [Accepted: 06/09/2021] [Indexed: 11/13/2022] Open
Abstract
The protein O6-methylguanine-DNA methyltransferase (MGMT) is able to repair the mutagenic O6-methylguanine adduct back to guanine. In this context, it may protect against colorectal cancer (CRC) formation associated with N-nitroso compounds. Such compounds may be endogenously formed by nitrosylation of amino acids, which can give rise to mutagenic O6-methylguanine (O6-MeG) and O6-carboxymethylguanine (O6-CMG) adducts. It is well-established that O6-MeG is repaired by MGMT. However, up to now, whether O6-CMG is repaired by this enzyme remains unresolved. Therefore, the aim of the present study was to analyze the fate of both types of O6-guanine adducts in the presence and absence of MGMT activity. To this end, MGMT activity was efficiently blocked by its chemical inhibitor O6-benzylguanine in human colon epithelial cells (HCEC). Exposure of cells to azaserine (AZA) caused significantly higher levels of both O6-MeG and O6-CMG adducts in MGMT-inhibited cells, with O6-CMG as the more abundant DNA lesion. Interestingly, MGMT inhibition did not result in higher levels of AZA-induced DNA strand breaks in spite of elevated DNA adduct levels. In contrast, MGMT inhibition significantly increased DNA strand break formation after exposure to temozolomide (TMZ), a drug that exclusively generates O6-MeG adducts. In line with this finding, the viability of the cells was moderately reduced by TMZ upon MGMT inhibition, whereas no clear effect was observed in cells treated with AZA. In conclusion, our study clearly shows that O6-CMG is repaired by MGMT in HCEC, thereby suggesting that MGMT might play an important role as a tumor suppressor in diet-mediated CRC.
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Affiliation(s)
- Tina Kostka
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany.,Institute of Food Science and Human Nutrition, Gottfried Wilhelm Leibniz University Hannover, 30167 Hannover, Germany
| | - Michael T Empl
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany
| | - Nina Seiwert
- Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Susanne M Geisen
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Pascal Hoffmann
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany
| | - Janine Adam
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany
| | - Bettina Seeger
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany.,Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Markus Christmann
- Department of Toxicology, University Medical Center Mainz, 55131 Mainz, Germany
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Jörg Fahrer
- Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Pablo Steinberg
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany.,Max Rubner-Institut, Federal Research Institute of Nutrition and Food, 76131 Karlsruhe, Germany
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24
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Bercu JP, Masuda-Herrera M, Johnson G, Czich A, Glowienke S, Kenyon M, Thomas R, Ponting DJ, White A, Cross K, Waechter F, Rodrigues MAC. Use of less-than-lifetime (LTL) durational limits for nitrosamines: Case study of N-Nitrosodiethylamine (NDEA). Regul Toxicol Pharmacol 2021; 123:104926. [PMID: 33862169 DOI: 10.1016/j.yrtph.2021.104926] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/02/2021] [Accepted: 04/06/2021] [Indexed: 11/30/2022]
Abstract
The ICH M7(R1) guideline describes a framework to assess the carcinogenic risk of mutagenic and carcinogenic pharmaceutical impurities following less-than-lifetime (LTL) exposures. This LTL framework is important as many pharmaceuticals are not administered for a patient's lifetime and as clinical trials typically involve LTL exposures. While there has been regulatory caution about applying LTL concepts to cohort of concern (COC) impurities such as N-nitrosamines, ICH M7 does not preclude this and indeed literature data suggests that the LTL framework will be protective of patient safety for N-nitrosamines. The goal was to investigate if applying the LTL framework in ICH M7 would control exposure to an acceptable excess cancer risk in humans. Using N-nitrosodiethylamine as a case study, empirical data correlating exposure duration (as a percentage of lifespan) and cancer incidence in rodent bioassays indicate that the LTL acceptable intake (AI) as derived using the ICH M7 framework would not exceed a negligible additional risk of cancer. Therefore, controlling N-nitrosamines to an LTL AI based on the ICH M7 framework is thus demonstrated to be protective for potential carcinogenic risk to patients over the exposure durations typical of clinical trials and many prescribed medicines.
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Affiliation(s)
- Joel P Bercu
- Gilead Sciences, Nonclinical Safety and Pathobiology (NSP), Foster City, CA, USA.
| | | | - George Johnson
- Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea, SA3 5DE, UK
| | - Andreas Czich
- Sanofi, R&D Preclinical Safety, D-65926, Frankfurt, Germany
| | | | - Michelle Kenyon
- Pfizer Worldwide Research and Development, Genetic Toxicology, Eastern Point Road, Groton, CT, USA
| | - Rob Thomas
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, LS11 5PS, UK
| | - David J Ponting
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, LS11 5PS, UK
| | - Angela White
- GlaxoSmithKline R&D, Park Road, Ware, Hertfordshire, SG12 0DP, UK
| | - Kevin Cross
- Leadscope Inc. an Instem Company, Columbus, OH, 43215, USA
| | - Fernanda Waechter
- Aché Laboratórios Farmacêuticos S.A., Rodovia Presidente Dutra, km 222,2, Porto da Igreja, 07034-904, Guarulhos, SP, Brazil
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25
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Kalubula M, Shen H, Khanam T. Assessment of carcinogenic and toxic substances in 'Insunko' herb. Toxicol Rep 2020; 7:468-474. [PMID: 32257823 PMCID: PMC7109397 DOI: 10.1016/j.toxrep.2020.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 02/26/2020] [Accepted: 03/05/2020] [Indexed: 12/23/2022] Open
Abstract
There has emerged a herb in Zambia called 'insunko' which has unknown chemical composition. The use of 'insunko' herb with unknown chemical composition has brought mixed feelings among many Zambians. This study, therefore, aimed to assess the toxic and carcinogenic substances in'insunko' herb. 'Insunko' herb was purchased from Chipata, Lusaka, Mpika, Mwense, Kitwe, and Solwezi. 5 samples were collected from each of these districts and were thoroughly mixed to give 6 consolidated samples (n = 6). Nicotine and, nitrosamines were analysed using UV spectrometer lambda 35 Perkin Elmer while trace metals were analysed using ICP-MS Inductively Coupled Plasma Mass Spectroscopy (Agilent Technologies, Santa Clara, CA, USA). Nicotine, nitrosamines, and trace metals were detected in high concentrations. The concentrations ranged from 3.87 to 9.83 mg/kg for nitrosamines and 10.94-34.01 mg/kg for nicotine. Hazard Indexes for arsenic, cadmium, chromium, manganese, and copper were greater than one (HI > 1). 'Insunko' herb is a potentially toxic and carcinogenic substance because it contains toxic and carcinogenic constituents in high concentrations. These toxic and carcinogenic constituents have been confirmed to cause gastrointestinal disorders, cancers, degenerative, cardiovascular, hematopoietic, neurologic and cognitive problems as well as male infertility.
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Affiliation(s)
- Maybin Kalubula
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Heqing Shen
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Tasawar Khanam
- Public Health and Environment Division, Department of Biosciences, COMSATS University, Islamabad, 45550, Pakistan
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26
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Spencer PS. Hypothesis: Etiologic and Molecular Mechanistic Leads for Sporadic Neurodegenerative Diseases Based on Experience With Western Pacific ALS/PDC. Front Neurol 2019; 10:754. [PMID: 31417480 PMCID: PMC6685391 DOI: 10.3389/fneur.2019.00754] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/27/2019] [Indexed: 12/12/2022] Open
Abstract
Seventy years of research on Western Pacific amyotrophic lateral sclerosis and Parkinsonism-dementia Complex (ALS/PDC) have provided invaluable data on the etiology, molecular pathogenesis and latency of this disappearing, largely environmental neurodegenerative disease. ALS/PDC is linked to genotoxic chemicals (notably methylazoxymethanol, MAM) derived from seed of the cycad plant (Cycas spp.) that were used as a traditional food and/or medicine in all three disease-affected Western Pacific populations. MAM, nitrosamines and hydrazines generate methyl free radicals that damage DNA (in the form of O6-methylguanine lesions) that can induce mutations in cycling cells and degenerative changes in post-mitotic cells, notably neurons. This paper explores exposures to naturally occurring and manmade sources of nitrosamines and hydrazines in association with sporadic forms of ALS (with or without frontotemporal degeneration), progressive supranuclear palsy, and Alzheimer disease. Research approaches are suggested to examine whether these associations might have etiological significance.
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Affiliation(s)
- Peter S Spencer
- Department of Neurology, School of Medicine and Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, United States
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27
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Ingersoll MA, Li X, Inman BA, Greiner JW, Black PC, Adam RM. Immunology, Immunotherapy, and Translating Basic Science into the Clinic for Bladder Cancer. Bladder Cancer 2018; 4:429-440. [PMID: 30417054 PMCID: PMC6218105 DOI: 10.3233/blc-180175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Fourth Annual Albert Institute Bladder Cancer Care and Research Symposium was held from September 14th–16th in Houston, Texas. The symposium covered a range of topics relevant to bladder cancer, including basic science aspects of immunology and immunotherapy that inform clinical management; intravesical therapy for non-muscle invasive disease; understanding the nuances of carcinoma in situ; and optimizing patient care and outcomes following therapy. The moving landscape of bladder cancer from an industry perspective was also discussed. In the following sections we discuss intrinsic and extrinsic factors, including the immune microenvironment and sex bias, in the context of bladder cancer; how these influence tumor development, progression, and treatment strategies; and how the interpretation of immune features in relation to molecular subtypes informs both treatment decisions and response. We conclude with a summary of key points that will need to be addressed to ensure best use of new knowledge in this area for improved clinical management of patients with bladder cancer.
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Affiliation(s)
- Molly A Ingersoll
- Unit of Dendritic Cell Immunobiology, Department of Immunology, Institut Pasteur, Paris, France.,Inserm U1223, Paris, France
| | - Xue Li
- Urological Diseases Research Center, Boston Children's Hospital, Boston, MA, USA.,Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Brant A Inman
- Division of Urology, Duke University Medical Center, Durham, NC, USA
| | - John W Greiner
- Laboratory of Tumor Immunology and Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Peter C Black
- Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Rosalyn M Adam
- Urological Diseases Research Center, Boston Children's Hospital, Boston, MA, USA.,Department of Surgery, Harvard Medical School, Boston, MA, USA
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28
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Fan T, Sun G, Zhao L, Cui X, Zhong R. QSAR and Classification Study on Prediction of Acute Oral Toxicity of N-Nitroso Compounds. Int J Mol Sci 2018; 19:E3015. [PMID: 30282923 PMCID: PMC6213880 DOI: 10.3390/ijms19103015] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 09/29/2018] [Accepted: 09/30/2018] [Indexed: 12/30/2022] Open
Abstract
To better understand the mechanism of in vivo toxicity of N-nitroso compounds (NNCs), the toxicity data of 80 NNCs related to their rat acute oral toxicity data (50% lethal dose concentration, LD50) were used to establish quantitative structure-activity relationship (QSAR) and classification models. Quantum chemistry methods calculated descriptors and Dragon descriptors were combined to describe the molecular information of all compounds. Genetic algorithm (GA) and multiple linear regression (MLR) analyses were combined to develop QSAR models. Fingerprints and machine learning methods were used to establish classification models. The quality and predictive performance of all established models were evaluated by internal and external validation techniques. The best GA-MLR-based QSAR model containing eight molecular descriptors was obtained with Q²loo = 0.7533, R² = 0.8071, Q²ext = 0.7041 and R²ext = 0.7195. The results derived from QSAR studies showed that the acute oral toxicity of NNCs mainly depends on three factors, namely, the polarizability, the ionization potential (IP) and the presence/absence and frequency of C⁻O bond. For classification studies, the best model was obtained using the MACCS keys fingerprint combined with artificial neural network (ANN) algorithm. The classification models suggested that several representative substructures, including nitrile, hetero N nonbasic, alkylchloride and amine-containing fragments are main contributors for the high toxicity of NNCs. Overall, the developed QSAR and classification models of the rat acute oral toxicity of NNCs showed satisfying predictive abilities. The results provide an insight into the understanding of the toxicity mechanism of NNCs in vivo, which might be used for a preliminary assessment of NNCs toxicity to mammals.
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Affiliation(s)
- Tengjiao Fan
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Guohui Sun
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Lijiao Zhao
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Xin Cui
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China.
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29
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Montesano R. Systemic Carcinogens (N-Nitroso Compounds) and Synergistic or Additive Effects in Respiratory Carcinogenesis. TUMORI JOURNAL 2018; 56:335-44. [PMID: 5514655 DOI: 10.1177/030089167005600603] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Systemic carcinogens induce respiratory tract tumors in various animals species. Typical examples of systemic carcinogens are the N-nitroso compounds, which require metabolic conversion to exert their carcinogenic effect. In this review particular emphasis is put on the comparative studies performed in the same species with different nitrosamines, providing an experimental model in which is possible to examine and correlate the biochemical changes preceding the development of detectable tumors and the carcinogenic effect. In addition studies describing synergistic or additive effects in respiratory carcinogenesis are reviewed and discussed.
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30
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De Bernardinis G, Guadagni S, Pistoia MA, Amicucci G, Masci C, Agnifili A, Carboni M. Gastric Juice Nitrite and Bacteria in Gastroduodenal Disease and Resected Stomach. TUMORI JOURNAL 2018; 69:231-7. [PMID: 6868141 DOI: 10.1177/030089168306900311] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The N-nitroso-compounds and the bacteriological contamination of gastric juice could represent a risk factor for cancer of the stomach when the mucosal barrier is altered. In the unresected stomach and gastric stump, the hypo-achlorhydria and bilopancreatic reflux permit the development of bacterial flora and the production of N-nitroso-compounds in the presence of nitrite. A survey was performed on 71 patients: 15 normal controls, 31 with gastroduodenal disease (9 gastrites, 10 gastric ulcers, 10 duodenal ulcers, 7 neoplasias), 20 patients with gastric resection (8 BI, 12 BII), using an endoscopic-histopathologic control and a chemical-bacteriological analysis of the gastric juice. We studied the gastric juice for the following parameters: pH, concentration of nitrite, identification of bacterial type, count and nitrate-reductase activity. An inverse relationship was found between the concentration of nitrite and the hydrogen ion concentration. In the alkaline gastric juice, we identified aerobic bacteria with nitrate-reductase activity and anaerobic bacteria. The latter has the ability to transform biliary salts into carcinogenic and cocarcinogenic compounds and to catalyze the nitrosations. The chemicobacteriological characteristics of the gastric juice from gastric ulcers (Johnson type I), atrophic gastrites, and resected stomachs lead one to think that there is a risk of carcinogenesis brought about by the N-nitroso-compounds.
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31
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Chicken egg fetal liver DNA and histopathologic effects of structurally diverse carcinogens and non-carcinogens. ACTA ACUST UNITED AC 2017; 69:533-546. [DOI: 10.1016/j.etp.2017.04.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 03/01/2017] [Accepted: 04/26/2017] [Indexed: 11/23/2022]
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32
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Preventive effect of berberine against DMBA-induced breast cancer in female Sprague Dawley rats. Biomed Pharmacother 2017; 92:207-214. [DOI: 10.1016/j.biopha.2017.05.069] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/01/2017] [Accepted: 05/12/2017] [Indexed: 02/05/2023] Open
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Wang Z, Zhang X. Chemopreventive Activity of Honokiol against 7, 12 - Dimethylbenz[a]anthracene-Induced Mammary Cancer in Female Sprague Dawley Rats. Front Pharmacol 2017; 8:320. [PMID: 28620301 PMCID: PMC5450001 DOI: 10.3389/fphar.2017.00320] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 05/15/2017] [Indexed: 12/30/2022] Open
Abstract
Breast cancer is a predominant cause of death in women across the globe. Chemoprevention by using natural, dietary or synthetic products has been appearing to be a fascinating approach to combat the growing burden of breast cancer. In the current study, we intended to explore the mechanisms of chemopreventive action of honokiol against 7, 12 - dimethylbenz[a]anthracene (DMBA)-induced mammary cancer in female Sprague Dawlely (SD) rats. We induced mammary cancer in SD rats by administering single dose of DMBA (80 mg/kg) through intra gastric route. Chemopreventive effects of honokiol (80 mg/kg, i.p.) were confirmed from its ameliorating effect on the DMBA-induced anomalies such as liver marker enzymes, Phases I and II metabolizing enzymes and oxidative stress markers. Further, honokiol reversed the DMBA-induced abnormalities in inflammatory cytokines levels and serum tumor markers. Additionally, histopathological examination of mammary tissue and protein expression analysis of NF-κB revealed that honokiol is effective against DMBA-induced mammary cancer. In summary, the results of our study support the chemopreventive feature of honokiol in mammary cancer.
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Affiliation(s)
- Zhenyu Wang
- Department of Breast Surgery, The Second Hospital of Jilin UniversityChangchun, China
| | - Xingyi Zhang
- Department of Thoracic Surgery, The Second Hospital of Jilin UniversityChangchun, China
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Abstract
The possibilities to define thresholds in general pharmacology and toxicology depend upon the proper knowledge and determination of the most sensitive parameters and relevant targets leading to clinical effects or toxicity. We are generally confronted with the statistical summation of very numerous individual responses and effects at the enzymological, sub-cellular, cellular, organ, or systemic level. In consequence, biological actions of chemicals reveal typical dose-response characteristics described by simple mathematics, and more or less sharp thresholds. Thresholds and targets can change after single and repeated (cumulative) doses by means of altered kinetics and metabolism, by adaptation and modified sensitivity of targets and/or receptors. Most sensitive targets and parameters do not always determine the real thresholds for clinical toxicity. Threshold and specificity of carcinogens can also be modified by similar conditions mentioned. Nutritional factors play an important role in experimental car-dnogenesis, and also for the cancer incidence in man. Frequently, secondary mechanisms such as overloading, induction of cellular growth, mechanical and chemical irritation and damage, and other conditions have simulated real carcinogenic properties of chemical molecules. The important question on the existence and validity of thresholds in carc/nogenes/s must be connected with a solid evaluation of the mode of action of the individual compounds. Otherwise, mathematical calculations of safety limits, definitions of acceptable risks and no-effect levels lack any biological foundation. Finally, the individual perception and social acceptance of risks reveal certain thresholds.
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Affiliation(s)
- Hartmut Uehleke
- Free University of Berlin, and Dept. of Toxicology Federal German Health Office (Bundesgesundheitsamt)
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35
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8 Final Report on the Safety Assessment of Triethanolamine, Diethanolamine, and Monoethanolamine. ACTA ACUST UNITED AC 2016. [DOI: 10.3109/10915818309142006] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Triethanolamine (TEA), Diethanolamine (DEA), and Monoethanolamine (MEA) are amino alcohols used in cosmetic formulations as emulsifiers, thickeners, wetting agents, detergents, and alkalizing agents. The nitrosation of the etha-nolamines may result in the formation of N-nitrosodiethanolamine (NDELA) which is carcinogenic in laboratory animals. In single-dose oral toxicity for rats, TEA was practically nontoxic to slightly toxic, and DEA and MEA were slightly toxic. Long-term oral ingestion of the ethanolamines by rats and guinea pigs produced lesions limited mainly to the liver and kidney. Long-term cutaneous applications to animals of the ethanolamines also produced evidence of hepatic and renal damage. TEA and DEA showed little potential for rabbit skin irritation in acute and subchronic skin irritation tests. MEA was corrosive to rabbit skin at a 30% concentration in a single semioccluded patch application and at a >10% concentration in 10 open applications over a period of 14 days. The ethanolamines were nonmutagenic in the Ames test and TEA is also nonmutagenic to Bacillus subtilis. TEA did not cause DNA-damage inducible repair in an unscheduled DNA synthesis test. TEA had no carcinogenic or cocarcinogenic activity when dermally applied to mice for 18 months. Clinical skin testing of TEA and cosmetic products containing TEA and DEA showed mild skin irritation in concentrations above 5%. There was very little skin sensitization. There was no phototoxicity or photosensitization reactions with products containing up to 20.04% TEA. A formulation containing 11.47% MEA and a formulation containing 1.6% DEA and 5.9% MEA were irritating to human skin in patch tests. The Panel concludes that TEA, DEA, and MEA are safe for use in cosmetic formulations designed for discontinuous, brief use followed by thorough rinsing from the surface of the skin. In products intended for prolonged contact with the skin, the concentration of ethanolamines should not exceed 5%. MEA should be used only in rinse-off products. TEA and DEA should not be used in products containing N-nitrosating agents.
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36
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Affiliation(s)
- Peter F Swann
- Courtauld Institute of Biochemistry, Middlesex Hospital Medical School, Mortimer Street, London W1P 7PN
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37
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Erratum: Salt tea consumption and esophageal cancer: A possible role of alkaline beverages in esophageal carcinogenesis. Int J Cancer 2015; 137:E2-8. [DOI: 10.1002/ijc.29550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 11/12/2022]
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Tolba R, Kraus T, Liedtke C, Schwarz M, Weiskirchen R. Diethylnitrosamine (DEN)-induced carcinogenic liver injury in mice. Lab Anim 2015; 49:59-69. [DOI: 10.1177/0023677215570086] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
The toxic properties of various nitrosamines in animals and humans are well established. The parenteral or oral administration of the smallest quantities of diethylnitrosamine (DEN) or dimethylnitrosamine (DMN) results in severe liver damage. Most prominent are intense neutrophilic infiltration, extensive centrilobular haemorrhagic necrosis, bile duct proliferation, fibrosis, and bridging necrosis that ends in hepatocarcinogenesis. Due to the robustness of the induced hepatic alterations, the application of DEN in rodents has become an attractive experimental model for studies aimed at understanding the pathogenetic alterations underlying the formation of liver cancer, which represents one of the most common malignancies in humans worldwide. However, several studies have shown that the hepatocarcinogenic effects of nitrosamines might vary with the genetic background of the animals, their sex, their age, and other factors that might impact the outcome of experimentation. We present general guidelines for working with DEN, and a detailed protocol that allows the establishment of highly reproducible liver cancer in mice. The outcome of liver injury after the application of DEN in mice, as estimated by the formation of cirrhosis and cancer, appears to be a suitable animal model for the analysis of some aspects and processes that promote the pathogenesis of hepatocellular carcinoma in humans.
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Affiliation(s)
- R Tolba
- Institute for Laboratory Animal Science and Experimental Surgery, University Hospital, RWTH Aachen University, Aachen, Germany
| | - T Kraus
- Institute for Occupational and Social Medicine, RWTH Aachen University, Aachen, Germany
| | - C Liedtke
- Department of Internal Medicine III, RWTH University Hospital Aachen, Aachen, Germany
| | - M Schwarz
- Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Toxicology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - R Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, Aachen, Germany for the Transregional Collaborative Research Center ‘Organ Fibrosis: From Mechanisms of Injury to Modulation of Disease’ (SFB/TRR57)
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Hazard assessment of nitrosamine and nitramine by-products of amine-based CCS: Alternative approaches. Regul Toxicol Pharmacol 2015; 71:601-23. [DOI: 10.1016/j.yrtph.2014.01.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 01/10/2014] [Accepted: 08/06/2014] [Indexed: 11/21/2022]
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Antitumor efficacy of tangeretin by targeting the oxidative stress mediated on 7,12-dimethylbenz(a) anthracene-induced proliferative breast cancer in Sprague-Dawley rats. Cancer Chemother Pharmacol 2014; 75:263-72. [PMID: 25431347 DOI: 10.1007/s00280-014-2629-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 11/11/2014] [Indexed: 12/14/2022]
Abstract
PURPOSE The aim of the present study was to assess the chemopreventive and chemotherapeutic efficacy of tangeretin on DMBA-induced oxidative stress in breast cancer-bearing Sprague-Dawley rats. METHODS In this study, the experimental animals were divided into five groups of six animals each. Group I was control, Group II was DMBA-induced breast cancer-bearing rats, Group III was tangeretin pre-treated (50 mg/kg body weight for 30 days orally) breast cancer-bearing animals, Group IV was tangeretin post-treated (50 mg/kg body weight for 30 days orally) and Group V was tangeretin (50 mg/kg body weight) alone treated animals. RESULTS We have observed the general characteristics of cancer, oxidative stress markers, breast cancer marker, antioxidants and histopathological changes in the experimental animals. We have recorded the body weight, tumor weights, tumor volume and antitumor activity of tangeretin in the experimental animals. Oxidative stress markers, like NO and LPO, and breast cancer marker CEA levels were significantly (p < 0.001, p < 0.05) increased as well as the antioxidants like SOD, CAT, GPx, GST, GSH, ascorbic acid and α-tocopherol were found to be significantly (p < 0.05) decreased in cancer-bearing Group II animals. Whereas, the enzymic and non-enzymic antioxidant levels were found to be significantly decreased in cancer-bearing animals. However, in tangeretin pre-treated and post- treated animals, the levels of antioxidants and breast cancer marker were found to be significantly (p < 0.05) reduced with a concomitant increase in the activities of the antioxidants (p < 0.05). In tangeretin alone treated Group V animals, no significant changes were observed in the levels of antioxidants and breast cancer marker. These results were adequately supported by the histopathological studies in the mammary tissues of the experimental animals. CONCLUSION From this study, we conclude that the administration of tangeretin was found to be beneficial against DMBA-induced oxidative stress in breast cancer-bearing animals. Hence, we strongly suggest that tangeretin is effective and efficient candidate for the treatment of experimental breast cancer.
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Habermeyer M, Roth A, Guth S, Diel P, Engel KH, Epe B, Fürst P, Heinz V, Humpf HU, Joost HG, Knorr D, de Kok T, Kulling S, Lampen A, Marko D, Rechkemmer G, Rietjens I, Stadler RH, Vieths S, Vogel R, Steinberg P, Eisenbrand G. Nitrate and nitrite in the diet: how to assess their benefit and risk for human health. Mol Nutr Food Res 2014; 59:106-28. [PMID: 25164923 DOI: 10.1002/mnfr.201400286] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/29/2014] [Accepted: 08/04/2014] [Indexed: 12/15/2022]
Abstract
Nitrate is a natural constituent of the human diet and an approved food additive. It can be partially converted to nitrogen monoxide, which induces vasodilation and thereby decreases blood pressure. This effect is associated with a reduced risk regarding cardiovascular disease, myocardial infarction, and stroke. Moreover, dietary nitrate has been associated with beneficial effects in patients with gastric ulcer, renal failure, or metabolic syndrome. Recent studies indicate that such beneficial health effects due to dietary nitrate may be achievable at intake levels resulting from the daily consumption of nitrate-rich vegetables. N-nitroso compounds are endogenously formed in humans. However, their relevance for human health has not been adequately explored up to now. Nitrate and nitrite are per se not carcinogenic, but under conditions that result in endogenous nitrosation, it cannot be excluded that ingested nitrate and nitrite may lead to an increased cancer risk and may probably be carcinogenic to humans. In this review, the known beneficial and detrimental health effects related to dietary nitrate/nitrite intake are described and the identified gaps in knowledge as well as the research needs required to perform a reliable benefit/risk assessment in terms of long-term human health consequences due to dietary nitrate/nitrite intake are presented.
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Affiliation(s)
- Michael Habermeyer
- Department of Food Chemistry and Toxicology, University of Kaiserslautern, Kaiserslautern, Germany**
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Dar NA, Bhat GA, Shah IA, Iqbal B, Rafiq R, Nabi S, Lone MM, Islami F, Boffetta P. Salt tea consumption and esophageal cancer: a possible role of alkaline beverages in esophageal carcinogenesis. Int J Cancer 2014; 136:E704-10. [PMID: 25209106 DOI: 10.1002/ijc.29204] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 01/26/2023]
Abstract
Salt tea is the most commonly used beverage in Kashmir, India, where esophageal squamous cell carcinoma (ESCC) is the most common cancer. Salt tea is brewed in a unique way in Kashmir, usually with addition of sodium bicarbonate, which makes salt tea alkaline. As little information about the association between salt tea drinking and ESCC was available, we conducted a large-scale case-control study to investigate this association in Kashmir. We recruited 703 histologically confirmed cases of ESCC and 1664 controls individually matched to cases for age, sex, and district of residence. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). Participants who consumed >1,250 ml day(-1) showed an increased risk of ESCC (OR = 2.60, 95% CIs = 1.68-4.02). Samovar (a special vessel for the beverage preparation) users (OR = 1.77, 95% CIs 1.25-2.50) and those who ate cereal paste with salt tea (OR = 2.14, 95% CIs = 1.55-2.94) or added bicarbonate sodium to salt tea (OR = 2.12, 95% CIs = 1.33-3.39) were at higher risk of ESCC than others. When analysis was limited to alkaline tea drinkers only, those who both consumed cereal paste with salt tea and used samovar vessel were at the highest risk (OR = 4.58, 95% CIs = 2.04-10.28). This study shows significant associations of salt tea drinking and some related habits with ESCC risk.
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Affiliation(s)
- Nazir Ahmad Dar
- Department of Biochemistry, University of Kashmir, Hazratbal, Srinagar, Jammu and Kashmir, India
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Buist H, Bausch-Goldbohm R, Devito S, Venhorst J, Stierum R, Kroese E. WITHDRAWN: Hazard assessment of nitrosamine and nitramine by-products of amine-based CCS: An alternative approach. Regul Toxicol Pharmacol 2014; 70:392. [DOI: 10.1016/j.yrtph.2014.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 01/10/2014] [Accepted: 01/12/2014] [Indexed: 11/25/2022]
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Abstract
The Family Smoking Prevention and Tobacco Control Act gives the U.S. Food and Drug Administration power to regulate tobacco products. This commentary calls for immediate regulation of the carcinogenic tobacco-specific nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) in cigarette tobacco as a logical path to cancer prevention. NNK and NNN, powerful carcinogens in laboratory animals, have been evaluated as "carcinogenic to humans" by the International Agency for Research on Cancer. NNK and NNN are present in the tobacco of virtually all marketed cigarettes; levels in cigarette smoke are directly proportional to the amounts in tobacco. The NNK metabolite NNAL, itself a strong carcinogen, is present in the urine of smokers and nonsmokers exposed to secondhand smoke. Some of the highest levels of NNK and NNN are found in U.S. products. It is well established that factors such as choice of tobacco blend, agricultural conditions, and processing methods influence levels of NNK and NNN in cigarette tobacco and cigarette smoke. Therefore, it is time to control these factors and produce cigarettes with 100 ppb or less each of NNK and NNN in tobacco, which would result in an approximate 15- to 20-fold reduction of these carcinogens in the mainstream smoke of popular cigarettes sold in the United States.
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Affiliation(s)
- Stephen S Hecht
- Author's Affiliation: Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota
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Human health risk assessment of nitrosamines and nitramines for potential application in CO2 capture. Regul Toxicol Pharmacol 2014; 69:250-5. [DOI: 10.1016/j.yrtph.2014.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 04/08/2014] [Accepted: 04/09/2014] [Indexed: 11/24/2022]
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Alam MN, Mandal SK, Roy K, Debnath SC. Safe amine based zinc dithiocarbamates for the vulcanization of carbon black reinforced natural rubber. J Appl Polym Sci 2014. [DOI: 10.1002/app.39988] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Md. Najib Alam
- Department of Chemistry; University of Kalyani; Kalyani, Nadia 741235 West Bengal India
| | - Swapan Kumar Mandal
- Department of Chemistry; University of Kalyani; Kalyani, Nadia 741235 West Bengal India
| | - Kumarjyoti Roy
- Department of Chemistry; University of Kalyani; Kalyani, Nadia 741235 West Bengal India
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Thomas JL, Hecht SS, Luo X, Ming X, Ahluwalia JS, Carmella SG. Thirdhand tobacco smoke: a tobacco-specific lung carcinogen on surfaces in smokers' homes. Nicotine Tob Res 2014; 16:26-32. [PMID: 23892827 PMCID: PMC3864489 DOI: 10.1093/ntr/ntt110] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 06/19/2013] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Thirdhand tobacco smoke consists of substances remaining on the surfaces or in the dust of areas where people have smoked. While previous studies have demonstrated the presence of nicotine and various other constituents of tobacco smoke on surfaces in smokers' homes, none has investigated the presence of tobacco-specific carcinogens. METHODS We used liquid chromatography-tandem mass spectrometry to analyze surface dust samples from both the homes of smokers and nonsmokers for the powerful tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). RESULTS We positively identified NNK on surfaces in 33 of 37 smokers' homes (700±788 pg/100cm(2) [range, not detected-3,500 pg/100cm(2)]), but only in 3 of 19 nonsmokers' homes (235±176 pg/100cm(2) in the homes where NNK was detected [range, not detected-435 pg/100cm(2)]). The differences in occurrence and levels of NNK in the homes of smokers and nonsmokers were significant (p < .0001). CONCLUSIONS The powerful tobacco-specific lung carcinogen NNK is present on surfaces in most homes occupied by smokers. Potential renters or buyers of apartments or homes should be notified if previous residents were smokers in order to avoid unnecessary exposure of their families to a potent lung carcinogen.
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Affiliation(s)
- Janet L Thomas
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN
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Edler L, Hart A, Greaves P, Carthew P, Coulet M, Boobis A, Williams GM, Smith B. Selection of appropriate tumour data sets for Benchmark Dose Modelling (BMD) and derivation of a Margin of Exposure (MoE) for substances that are genotoxic and carcinogenic: considerations of biological relevance of tumour type, data quality and uncertainty assessment. Food Chem Toxicol 2013; 70:264-89. [PMID: 24176677 DOI: 10.1016/j.fct.2013.10.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/17/2013] [Accepted: 10/17/2013] [Indexed: 10/26/2022]
Abstract
This article addresses a number of concepts related to the selection and modelling of carcinogenicity data for the calculation of a Margin of Exposure. It follows up on the recommendations put forward by the International Life Sciences Institute - European branch in 2010 on the application of the Margin of Exposure (MoE) approach to substances in food that are genotoxic and carcinogenic. The aims are to provide practical guidance on the relevance of animal tumour data for human carcinogenic hazard assessment, appropriate selection of tumour data for Benchmark Dose Modelling, and approaches for dealing with the uncertainty associated with the selection of data for modelling and, consequently, the derived Point of Departure (PoD) used to calculate the MoE. Although the concepts outlined in this article are interrelated, the background expertise needed to address each topic varies. For instance, the expertise needed to make a judgement on biological relevance of a specific tumour type is clearly different to that needed to determine the statistical uncertainty around the data used for modelling a benchmark dose. As such, each topic is dealt with separately to allow those with specialised knowledge to target key areas of guidance and provide a more in-depth discussion on each subject for those new to the concept of the Margin of Exposure approach.
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Affiliation(s)
- Lutz Edler
- German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
| | - Andy Hart
- The Food and Environment Research Agency - FERA, Sand Hutton, YO41 1LZ York, United Kingdom.
| | - Peter Greaves
- Department of Cancer Studies and Molecular Medicine, University of Leicester, LE2 7LX Leicester, United Kingdom.
| | - Philip Carthew
- Unilever, Colworth House Sharnbrook, MK44 1LQ Bedfordshire, United Kingdom.
| | - Myriam Coulet
- Nestlé Research Centre, Vers-Chez-Les-Blanc, 1000 Lausanne, Switzerland.
| | - Alan Boobis
- Imperial College, Hammersmith Campus, Ducane Road, W12 0NN London, United Kingdom.
| | - Gary M Williams
- New York Medical College, Basic Science Building, Room 413, Valhalla, NY 10595, United States.
| | - Benjamin Smith
- Firmenich, Rue de la Bergere 7, 1217-Meyrin 2, Switzerland.
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Borteh HM, Gallovic MD, Sharma S, Peine KJ, Miao S, Brackman DJ, Gregg K, Xu Y, Guo X, Guan J, Bachelder EM, Ainslie KM. Electrospun acetalated dextran scaffolds for temporal release of therapeutics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:7957-7965. [PMID: 23725054 DOI: 10.1021/la400541e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Electrospun acetalated dextran (Ac-DEX) scaffolds were fabricated to encapsulate resiquimod, an immunomodulatory toll-like-receptor (TLR) agonist. Ac-DEX has been used to fabricate scaffolds for sustained and temporal delivery of therapeutics because it has tunable degradation rates that are dependent on its synthesis reaction time or the molecular weight of dextran. Additionally, as opposed to commonly electrospun polyesters that shift the local pH upon degradation, the degradation products of Ac-DEX are pH-neutral: dextran, an alcohol, and the metabolic byproduct acetone. Formulations of Ac-DEX with two different degradation rates were used in this study. The effects of electrospinning conditions on the scaffold size and morphology were examined as well as fibroblast adhesion as imaged with fluorescence microcopy and scanning electron microscopy. Macrophage (MΦ) viability further indicates that the scaffolds are cytocompatible. Also, the controlled release profiles of resiquimod from loaded scaffolds and nitric oxide (NO) production by MΦ incubated with these scaffolds show the potential for Ac-DEX scaffolds to be used to temporally and efficiently deliver therapeutics. Overall, we present a novel scaffold that can have tunable and unique drug release rates for tissue engineering, drug delivery, immunomodulation, and wound healing applications.
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Affiliation(s)
- Hassan M Borteh
- Division of Pharmaceutics, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, USA
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Chandan PA, Remias JE, Neathery JK, Liu K. Morpholine nitrosation to better understand potential solvent based CO₂ capture process reactions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:5481-5487. [PMID: 23614812 DOI: 10.1021/es4003108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The amine assisted CO₂ capture process from coal fired power plants strives for the determination of degradation components and its consequences. Among them, nitrosamine formation and their emissions are of particular concern due to their environmental and health effects. The experiments were conducted using morpholine as a representative secondary amine as a potential CO₂ capture solvent with 100 ppm standard NO₂ gas to better understand the nitrosamine reaction pathways under scrubber and stripper conditions. The role of nitrite in the nitrosation reaction was probed at elevated temperatures. The effects of different concentrations of nitrite on morpholine were evaluated. Formation rate, decomposition rates, activation energy, and the possible reaction pathways are elaborated. Thermal stability tests at 135 °C indicated the decomposition of nitrosamines at the rate of 1 μg/(g h) with activation energy of 131 kJ/mol. The activation energy for the reaction of morpholine with sodium nitrite was found as 101 kJ/mol. Different reaction pathways were noted for lower temperature reactions with NO₂ gas and higher temperature reactions with nitrite.
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Affiliation(s)
- Payal A Chandan
- Center for Applied Energy Research, University of Kentucky, 2540 Research Park Drive, Lexington, Kentucky 40511, United States
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