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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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Ponting DJ, Foster RS. Drawing a Line: Where Might the Cohort of Concern End? Org Process Res Dev 2023. [DOI: 10.1021/acs.oprd.3c00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Affiliation(s)
- David J. Ponting
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds LS11 5PS, United Kingdom
| | - Robert S. Foster
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds LS11 5PS, United Kingdom
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Ponting DJ, Dobo KL, Kenyon MO, Kalgutkar AS. Strategies for Assessing Acceptable Intakes for Novel N-Nitrosamines Derived from Active Pharmaceutical Ingredients. J Med Chem 2022; 65:15584-15607. [PMID: 36441966 DOI: 10.1021/acs.jmedchem.2c01498] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The detection of N-nitrosamines, derived from solvents and reagents and, on occasion, the active pharmaceutical ingredient (API) at higher than acceptable levels in drug products, has led regulators to request a detailed review for their presence in all medicinal products. In the absence of rodent carcinogenicity data for novel N-nitrosamines derived from amine-containing APIs, a conservative class limit of 18 ng/day (based on the most carcinogenic N-nitrosamines) or the derivation of acceptable intakes (AIs) using structurally related surrogates with robust rodent carcinogenicity data is recommended. The guidance has implications for the pharmaceutical industry given the vast number of marketed amine-containing drugs. In this perspective, the rate-limiting step in N-nitrosamine carcinogenicity, involving cytochrome P450-mediated α-carbon hydroxylation to yield DNA-reactive diazonium or carbonium ion intermediates, is discussed with reference to the selection of read-across analogs to derive AIs. Risk-mitigation strategies for managing putative N-nitrosamines in the preclinical discovery setting are also presented.
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Affiliation(s)
- David J Ponting
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds LS11 5PS, United Kingdom
| | - Krista L Dobo
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Michelle O Kenyon
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Amit S Kalgutkar
- Medicine Design, Pfizer Worldwide Research, Development, and Medical, 1 Portland Street, Cambridge, Massachusetts 02139, United States
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Thomas R, Tennant RE, Oliveira AAF, Ponting DJ. What Makes a Potent Nitrosamine? Statistical Validation of Expert-Derived Structure-Activity Relationships. Chem Res Toxicol 2022; 35:1997-2013. [PMID: 36302501 PMCID: PMC9682520 DOI: 10.1021/acs.chemrestox.2c00199] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The discovery of carcinogenic nitrosamine impurities above the safe limits in pharmaceuticals has led to an urgent need to develop methods for extending structure-activity relationship (SAR) analyses from relatively limited datasets, while the level of confidence required in that SAR indicates that there is significant value in investigating the effect of individual substructural features in a statistically robust manner. This is a challenging exercise to perform on a small dataset, since in practice, compounds contain a mixture of different features, which may confound both expert SAR and statistical quantitative structure-activity relationship (QSAR) methods. Isolating the effects of a single structural feature is made difficult due to the confounding effects of other functionality as well as issues relating to determining statistical significance in cases of concurrent statistical tests of a large number of potential variables with a small dataset; a naïve QSAR model does not predict any features to be significant after correction for multiple testing. We propose a variation on Bayesian multiple linear regression to estimate the effects of each feature simultaneously yet independently, taking into account the combinations of features present in the dataset and reducing the impact of multiple testing, showing that some features have a statistically significant impact. This method can be used to provide statistically robust validation of expert SAR approaches to the differences in potency between different structural groupings of nitrosamines. Structural features that lead to the highest and lowest carcinogenic potency can be isolated using this method, and novel nitrosamine compounds can be assigned into potency categories with high accuracy.
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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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Animal Models: A Useful Tool to Unveil Metabolic Changes in Hepatocellular Carcinoma. Cancers (Basel) 2020; 12:cancers12113318. [PMID: 33182674 PMCID: PMC7696782 DOI: 10.3390/cancers12113318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 11/05/2020] [Accepted: 11/08/2020] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Hepatocellular carcinoma (HCC) represents an important health problem. At the moment, systemic therapies offered only modest clinical benefits. Thus, HCC represents a cancer extremely difficult to treat, and therapeutic breakthroughs are urgently needed. Metabolic reprogramming of neoplastic cells has been recognized as one of the core hallmarks of cancer. Experimental animal models represent an important tool that allows to investigate metabolic changes underlying HCC development and progression. In the present review, we characterize available rodent models of hepatocarcinogenesis. Moreover, we discuss the possibility that pharmacological targeting of Warburg metabolism may represent an additional tool to improve already available therapeutic approaches for HCC. Abstract Hepatocellular carcinoma (HCC) is one the most frequent and lethal human cancers. At present, no effective treatment for advanced HCC exist; therefore, the overall prognosis for HCC patients remains dismal. In recent years, a better knowledge of the signaling pathways involved in the regulation of HCC development and progression, has led to the identification of novel potential targets for therapeutic strategies. However, the obtained benefits from current therapeutic options are disappointing. Altered cancer metabolism has become a topic of renewed interest in the last decades, and it has been included among the core hallmarks of cancer. In the light of growing evidence for metabolic reprogramming in cancer, a wide number of experimental animal models have been exploited to study metabolic changes characterizing HCC development and progression and to further expand our knowledge of this tumor. In the present review, we discuss several rodent models of hepatocarcinogenesis, that contributed to elucidate the metabolic profile of HCC and the implications of these changes in modulating the aggressiveness of neoplastic cells. We also highlight the apparently contrasting results stemming from different animal models. Finally, we analyze whether these observations could be exploited to improve current therapeutic strategies for HCC.
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MicroRNAs in Animal Models of HCC. Cancers (Basel) 2019; 11:cancers11121906. [PMID: 31805631 PMCID: PMC6966618 DOI: 10.3390/cancers11121906] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 12/11/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality. Molecular heterogeneity and absence of biomarkers for patient allocation to the best therapeutic option contribute to poor prognosis of advanced stages. Aberrant microRNA (miRNA) expression is associated with HCC development and progression and influences drug resistance. Therefore, miRNAs have been assayed as putative biomarkers and therapeutic targets. miRNA-based therapeutic approaches demonstrated safety profiles and antitumor efficacy in HCC animal models; nevertheless, caution should be used when transferring preclinical findings to the clinics, due to possible molecular inconsistency between animal models and the heterogeneous pattern of the human disease. In this context, models with defined genetic and molecular backgrounds might help to identify novel therapeutic options for specific HCC subgroups. In this review, we describe rodent models of HCC, emphasizing their representativeness with the human pathology and their usefulness as preclinical tools for assessing miRNA-based therapeutic strategies.
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Abstract
For a large number of N-nitroso compounds a comparison of their carcinogenic effects in rats and Syrian golden hamsters has been made. Nitrosamines, which require metabolic activation, and nitrosoalkylamides, which do not, produce quite different tumor responses. There are also large differences in the types of tumor induced in rats and in hamsters. In all the studies doses of the various compounds, equimolar to the extent that was possible, are administered orally. Continuous doses (in drinking water or food) often produce a response different from that after administration of the same compound in pulsed doses (by gavage), even though the same total dose is delivered. Continuous doses of nitrosamines are usually more effective than pulsed doses, but with the nitrosoalkylureas, the reverse is more generally the case. Rat and hamster liver is a common target of many nitrosamines, but rarely of nitrosamides. The most common site of tumor induction in rats by N-nitroso compounds is the esophagus, but the hamster esophagus never responds. The pancreas duct of the hamster is a common target of nitrosamines containing a beta-oxygenated propyl group, but pancreas duct tumors are never seen in rats. Nitrosomethyl-n-alkylamines (with an even numbered carbon chain) induce bladder tumors in rats and hamsters. Many nitrosoalkylureas induce tumors of the nervous system in rats, as well as a great variety of other tumors. In hamsters, nitrosoalkylureas give rise only to tumors of the forestomach and spleen, but no tumors of the nervous system. The similar carcinogenic actions of certain groups of N-nitroso compounds can be related to their generation, directly or by metabolism, of similar simple moieties having certain organs as their target.
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Affiliation(s)
- W Lijinsky
- BRI-Basic Research Program, NCI-Frederick Cancer Research Facility, MD 21701
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9
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Abstract
The alkylation of nucleic acids of the liver of rats and Syrian hamsters was measured in relation to carcinogenesis by a number of nitrosamines and azoxyalkanes, most of which induce tumors of the liver in both species following chronic treatment. Two compounds, nitroso-2,6-dimethylmorpholine and nitrosobis(2-hydroxypropyl)amine were not liver carcinogens in rats, but did induce liver tumors in hamsters; there was much less alkylation by these compounds in the rat than in the hamster. In both rats and hamsters, azoxymethane produced a greater extent of alkylation, both at N-7 and O-6 guanine, than did nitrosodimethylamine, although the former is no more potent than the latter as a carcinogen in either species. Both methyl groups of azoxymethane gave rise to N-7 methylation. Nitrosobis(2-oxopropyl)amine (BOP) and nitroso(2-hydroxypropyl) (2-oxopropyl)amine (HPOP) produced considerable methylation of liver nucleic acids in both species, comparable with that by nitrosodimethylamine, and they induce liver tumors in both rats and hamsters. However, in male rats the extent of alkylation by BOP was much smaller than in females and no O-6-methylation was detected in the former; this correlates with the failure of BOP to induce liver tumors in male rats by gavage, whereas liver tumors are induced in females.
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Ying TS, Sarma DS, Farber E. The sequential analysis of liver cell necrosis: inhibition of diethylnitrosamine- and dimethylnitrosamine-induced acute liver cell death by posttreatment with diethyldithiocarbamate. THE AMERICAN JOURNAL OF PATHOLOGY 1980; 99:159-74. [PMID: 6244740 PMCID: PMC1903480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Posttreatment with diethyldithiocarbamate (DEDTC) largely prevented the development of acute hepatocellular necrosis induced by diethylnitrosamine (DEN) and dimethylnitrosamine (DMN) in male Fischer rats as monitored by the release of glutamate-pyruvate transaminase and sorbitol dehydrogenase into the serum and by histologic examination. Liver cell necrosis was evident with a dose of 25 mg of DEN/kg and was progressive with increasing doses of DEN. DEDTC (50 mg/kg; three times at 4-hour intervals) was given at 4 or 8 hours after the administration of DEN (100 mg/kg), time points at which at least 50% and 75%, respectively, of the administered DEN had disappeared from both the serum and liver. Under these conditions, DEDTC prevented liver cell necrosis, except for a few isolated cells. Similar inhibition was also observed when DEDTC was given 4 hours after the administration of a necrogenic dose of DMN (20 mg/kg). DEDTC, when administered 4 hours after DEN, delayed the rate of clearance of DEN and of ethylation of DNA and RNA but did not significantly affect the total extent of ethylation of rat liver nucleic acids. These results offer further support for the multistep hypothesis for the development of liver cell necrosis.
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12
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Hietanen E. Modification of hepatic drug metabolizing enzyme activities and their induction by dietary protein. GENERAL PHARMACOLOGY 1980; 11:443-50. [PMID: 7419037 DOI: 10.1016/0306-3623(80)90030-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Lai DY, Arcos JC, Argus MF. Factors influencing the microsome- and mitochondria-catalyzed in vitro binding of diethylnitrosamine and N-nitrosopiperidine to deoxyribonucleic acid. Biochem Pharmacol 1979; 28:3545-50. [PMID: 43737 DOI: 10.1016/0006-2952(79)90399-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Czok G. [Interactions between nutrition and drugs]. ZEITSCHRIFT FUR ERNAHRUNGSWISSENSCHAFT 1976; 15:188-200. [PMID: 969708 DOI: 10.1007/bf02018441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
It is only recently that the question of interaction between nutrition and drugs has been investigated. Generally there are two ways by which such an interaction may occur. On the one hand the food-intake and its composition may influence the effects of drugs by altering their pharmacokinetics. In most cases the abosrption of drugs and thereby also their biological effects are decreased when they are taken together with food, by only a few drugs the opposite effects have been observed. Furthermore the biotransformation of drugs may be inhibited by giving a diet poor in proteins. A diet rich in meat or in vegetables may also influence the urine pH in the more acid or basic direction and in this way the renal excretion of drugs may be changed considerably since drugs are generally either weak organic acid or bases. On the other hand drugs may also interfere with the availability and utilization of certain nutrients e.g. vitamins, electrolytes or trace elements. Such interaction could be observed when giving for example antibiotics, alcohol, contraceptives, anticonvulsives or laxatives over a long period. Deficiency of certain nutritional factors or even diseases can then be the consequence of such interactions.
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Alonso A, Arnold HP. Stimulation of amino acids incorporation into rat liver nonhistone chromatin proteins after treatment with diethyl-nitrosamine. FEBS Lett 1974; 41:8-10. [PMID: 4854411 DOI: 10.1016/0014-5793(74)80940-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Althoff J, Hilfrich J, Krüger FW, Bertram B. The carcinogenic effect of 2-oxo-propyl-propylnitrosamine in Sprague-Dawley rats. ZEITSCHRIFT FUR KREBSFORSCHUNG UND KLINISCHE ONKOLOGIE. CANCER RESEARCH AND CLINICAL ONCOLOGY 1974; 81:23-8. [PMID: 4363782 DOI: 10.1007/bf00303597] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Clapp NK. Carcinogenicity of nitrosamines and methanesulphonate esters given intraperitoneally, in RF mice. Int J Cancer 1973; 12:728-33. [PMID: 4364800 DOI: 10.1002/ijc.2910120320] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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23
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Krüger FW. Metabolism of nitrosamines in vivo. II. On the methylation of nucleic acids by aliphatic di-n-alkyl-nitrosamines in vivo, caused by beta-oxydation: the increased formation of 7-methyl-guanine after application of beta-hydroxypropyl-propyl-nitrosamine compared to that after application of di-n-propyl-nitrosamine. ZEITSCHRIFT FUR KREBSFORSCHUNG UND KLINISCHE ONKOLOGIE. CANCER RESEARCH AND CLINICAL ONCOLOGY 1973; 79:90-7. [PMID: 4281178 DOI: 10.1007/bf00284383] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Weyland P, Gross HJ, Dannenberg H. [Urinary 7-methyl guanine excretion of the rat after a single application of various carcinogens]. ZEITSCHRIFT FUR KREBSFORSCHUNG UND KLINISCHE ONKOLOGIE. CANCER RESEARCH AND CLINICAL ONCOLOGY 1972; 77:141-9. [PMID: 4260567 DOI: 10.1007/bf00304052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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26
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Mirvish SS, Sidransky H. Labeling in vivo of rat liver proteins by tritium-labeled dimethylnitrosamine. Effect of prior treatment with 3-methylcholanthrene, phenobarbitone, dimethylformamide, diethyl-formamide, aminoacetonitrile, ethionine and carbon tetrachloride. Biochem Pharmacol 1971; 20:3493-9. [PMID: 5132895 DOI: 10.1016/0006-2952(71)90454-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Krüger FW. [Metabolism of nitrosamines in vivo. I. Evidence for -oxydation of aliphatic di-n-alkylnitrosamines: the stimultaneous formation of 7-methylguanine besides 7-propyl- or 7-butylguanine after application of di-n-propyl- or di-n-butylnitrosamine]. ZEITSCHRIFT FUR KREBSFORSCHUNG UND KLINISCHE ONKOLOGIE. CANCER RESEARCH AND CLINICAL ONCOLOGY 1971; 76:145-54. [PMID: 4255598 DOI: 10.1007/bf00284425] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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28
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Haerlin R, Süssmuth R, Lingens F. Mechanism of mutagenesis by N-methyl-N'-nitro-N-nitroso-guanidine (MNNG) V. Methylation of DNA by N-trideuteriomethyl-N'-nitro-N-nitroso-guanidine (D(3)-MNNG). FEBS Lett 1970; 9:175-176. [PMID: 11947662 DOI: 10.1016/0014-5793(70)80347-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- R Haerlin
- Institut für Mikrobiologie und Molekularbiologie, Universität Hohenheim, 7 70, Stuttgart, Germany
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Texler KC, Roman W, Irving EA. The effect of pregnancy on the sensitivity of the rabbit liver to diethyl nitrosamine. Aust N Z J Obstet Gynaecol 1970; 10:175-9. [PMID: 5273645 DOI: 10.1111/j.1479-828x.1970.tb00425.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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30
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Kr�ger FW, R�cker U, Wiessler M. Untersuchungen �ber die Einwirkung von S-Adenosylmethionin auf die Methylierung von Ribonukleins�uren der Leber durch Dimethylnitrosamin in vivo. J Cancer Res Clin Oncol 1970. [DOI: 10.1007/bf00525881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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32
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[Histochemical investigations of carcinogenesis in rat liver after continuous application of diethylnitrosamine]. J Cancer Res Clin Oncol 1969. [PMID: 4309584 DOI: 10.1007/bf00524337] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Viale GL. Biochemical patterns in brain tumours. 3. Transfer ribonucleic acid. Acta Neurochir (Wien) 1969; 21:123-37. [PMID: 5365148 DOI: 10.1007/bf01540920] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Takayama S, Muramatsu M. Incorporation of tritiated dimethylnitrosamine into subcellular fractions of mouse liver after long term administration of dimethylnitrosamine. ZEITSCHRIFT FUR KREBSFORSCHUNG 1969; 73:172-9. [PMID: 4245381 DOI: 10.1007/bf00525519] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Abstract
The incidences of lung tumors and thymic lymphomas were increased in young adult male RF mice receiving 30 milligrams of methyl meth anesulfonate per kilogram of body weight daily in the drinking water throughout life. Differences in oncogenicity between treatment with methyl methanesulfonate and with dimethylnitrosamine or diethylnitrosamine suggest a qualitative difference between the site (or sites) of alkylation by methyl methanesulfonate and by dimethylnitrosamine or diethylnitrosamine within the nucleic acids.
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Lijinsky W, Loo J, Ross AE. Mechanism of alkylation of nucleic acids by nitrosodimethylamine. Nature 1968; 218:1174-5. [PMID: 5656642 DOI: 10.1038/2181174b0] [Citation(s) in RCA: 141] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Lee KT, Goodall CM. Methylation of ribonucleic acid and deoxyribonucleic acid and tumour induction in livers of hypophysectomized rats treated with dimethylnitrosamine. Biochem J 1968; 106:767-8. [PMID: 5639932 PMCID: PMC1198570 DOI: 10.1042/bj1060767] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Schauer A, Kunze E. Enzymhistochemische und autoradiographische Untersuchungen w�hrend der Cancerisierung der Rattenleber mit Di�thylnitrosamin. J Cancer Res Clin Oncol 1968. [DOI: 10.1007/bf00537000] [Citation(s) in RCA: 82] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Abstract
Diethylnitrosamine was continuously administered to rats at a dose rate of low toxicity. Ninety-two percent of the animals died with multicentrical hepatocellular carcinomata within a narrow and highly reproducible time interval. Discontinuing the carcinogen during the experiment resulted in a prolonged median time until death, a reduced tumor yield, and a lessened slope of the dose-response curve. Partial hepatectomy after discontinuation of the drug did not change either tumor yield or time of death. The obtained dose-response relationships support the concept that carcinogenic effects of single doses are irreversible and cumulative. Daily, low-dose, total-body x-irradiation had no significant effect on the response of rat liver to the carcinogen.
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Lawley PD. Effects of some chemical mutagens and carcinogens on nucleic acids. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1966; 5:89-131. [PMID: 5337700 DOI: 10.1016/s0079-6603(08)60232-9] [Citation(s) in RCA: 280] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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