HESI GTTC ring trial: Concordance between Ames and rodent carcinogenicity outcomes for N-nitrosamines (NAs) with rat and hamster metabolic conditions

A multi-sector study (i.e., Ring Trial) was designed to improve the in vitro detection of N-nitrosamine (NA)-associated mutagenicity by optimizing the bacterial reverse mutation (i.e., Ames) assay protocol and testing various conditions on the sensitivity and specificity for the prediction of rodent carcinogenicity. A total of 29 NAs and 3 N-nitroso drug-like compounds from different structural classes and carcinogenicity outcomes were tested (two independent laboratories per compound) across 5 bacterial strains using a 30-min pre-incubation protocol. To evaluate the impact of different metabolic activating systems (MASs), testing conditions included the use of 10 or 30 % liver S9 fractions prepared from rats or hamsters pretreated with inducers of enzymatic activity. Results indicate that E. coli and Salmonella typhimurium strains detecting single base pair mutations, coupled with MASs containing 30 % hamster S9s were the most sensitive (90 %) for identifying NAs that are rodent carcinogens. Regarding MAS combinations, the highest sensitivity was 30 % rat and 30 % hamster (93 %), but has low specificity (45 %), with good laboratory agreement for the Ames calls (91 %). DMSO and water were considered suitable solvents, except for small-molecular weight alkyl NAs. These results will support harmonized Ames testing of NAs, giving high confidence for a negative result.

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Journal
Regulatory Toxicology and Pharmacology
Published
2025-04-29
DOI
https://doi.org/10.1016/j.yrtph.2025.105835
Citations
9
Primary Topic
Glutathione Transferases and Polymorphisms
Type
article
Field-Weighted Citation Impact
7.25
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article

HESI GTTC ring trial: Concordance between Ames and rodent carcinogenicity outcomes for N-nitrosamines (NAs) with rat and hamster metabolic conditions

Michelle Schaefer, Robert A. Jolly, Joel S Christensen, Yi Yan Yang et al.
9 citations
Regulatory Toxicology and Pharmacology
Glutathione Transferases and Polymorphisms
7.25
article

HESI GTTC ring trial: Concordance between Ames and rodent carcinogenicity outcomes for N-nitrosamines (NAs) with rat and hamster metabolic conditions

Michelle Schaefer, Robert A. Jolly, Joel S Christensen, Yi Yan Yang, Aisar H. Atrakchi, Penny Leavitt, Yang Liao, Joanne Elloway, Jessica Noteboom, D. Thomas, Robert H. Heflich, Walter M.A. Westerink, Kerstin Waese, Pavan Gollapudi, Raymond Hoffmans, Rosalie K. Elespuru, Alisa Vespa, Alejandra Trejo‐Martin, Verena Ziegler, Joel P. Bercu, Stéphanie Simon, Andreas Zeller, Andreas Czich, Raj D. Gandhi, Rachael E. Tennant, Jennifer Cheung, Victoria Hargreaves, Timothy J. McGovern, Zhanna Sobol, C Marchand, Andreas Hellmann, Connie L. Chen, Anthony M. Lynch, Maik Schuler, Michelle E. Bishop, J Dieckhoff, Raechel Puglisi, Roland Froetschl, Katerine K McGettigan, Connor Glick, Tetyana Cheairs
article en
9 citations

Abstract

A multi-sector study (i.e., Ring Trial) was designed to improve the in vitro detection of N-nitrosamine (NA)-associated mutagenicity by optimizing the bacterial reverse mutation (i.e., Ames) assay protocol and testing various conditions on the sensitivity and specificity for the prediction of rodent carcinogenicity. A total of 29 NAs and 3 N-nitroso drug-like compounds from different structural classes and carcinogenicity outcomes were tested (two independent laboratories per compound) across 5 bacterial strains using a 30-min pre-incubation protocol. To evaluate the impact of different metabolic activating systems (MASs), testing conditions included the use of 10 or 30 % liver S9 fractions prepared from rats or hamsters pretreated with inducers of enzymatic activity. Results indicate that E. coli and Salmonella typhimurium strains detecting single base pair mutations, coupled with MASs containing 30 % hamster S9s were the most sensitive (90 %) for identifying NAs that are rodent carcinogens. Regarding MAS combinations, the highest sensitivity was 30 % rat and 30 % hamster (93 %), but has low specificity (45 %), with good laboratory agreement for the Ames calls (91 %). DMSO and water were considered suitable solvents, except for small-molecular weight alkyl NAs. These results will support harmonized Ames testing of NAs, giving high confidence for a negative result.

Regulatory Toxicology and PharmacologyVol. 161
AstraZeneca (United Kingdom) (GB), Roche (Switzerland) (CH), Federal Institute for Drugs and Medical Devices (DE), Merck & Co., Inc., Rahway, NJ, USA (United States) (US), Health Canada (CA), National Center for Toxicological Research (US), Boehringer Ingelheim (Germany) (DE), Center for Drug Evaluation and Research (US), Center for Devices and Radiological Health (US), Charles River Laboratories (Netherlands) (NL), Bristol-Myers Squibb (Germany) (DE), Merck KGaA, Darmstadt (Germany) (DE), Eli Lilly (United States) (US), Pfizer (United States) (US), New York Medical College (US), LabCorp (United States) (US), AbbVie (United States) (US), Sanofi (France) (FR), North Hertfordshire College (GB), Bristol-Myers Squibb (Ireland) (IE), Pivot Bio (United States) (US), Bristol-Myers Squibb (United Kingdom) (GB), Macula Vision Research Foundation (US), Sanofi (Germany) (DE), Boehringer Ingelheim (France) (FR), Gilead Sciences (United States) (US), The Bristol-Myers Squibb Children's Hospital (US), Health and Environmental Sciences Institute (US), Bayer (Germany) (DE)
Zero hunger
Openalex Percentile: Top 3%
Glutathione Transferases and Polymorphisms
7.25
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