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Li X, Le Y, Seo JE, Guo X, Li Y, Chen S, Mittelstaedt RA, Moore N, Guerrero S, Sims A, King ST, Atrakchi AH, McGovern TJ, Davis-Bruno KL, Keire DA, Elespuru RK, Heflich RH, Mei N. Revisiting the mutagenicity and genotoxicity of N-nitroso propranolol in bacterial and human in vitro assays. Regul Toxicol Pharmacol 2023; 141:105410. [PMID: 37210026 DOI: 10.1016/j.yrtph.2023.105410] [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: 03/27/2023] [Revised: 05/05/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023]
Abstract
Propranolol is a widely used β-blocker that can generate a nitrosated derivative, N-nitroso propranolol (NNP). NNP has been reported to be negative in the bacterial reverse mutation test (the Ames test) but genotoxic in other in vitro assays. In the current study, we systematically examined the in vitro mutagenicity and genotoxicity of NNP using several modifications of the Ames test known to affect the mutagenicity of nitrosamines, as well as a battery of genotoxicity tests using human cells. We found that NNP induced concentration-dependent mutations in the Ames test, both in two tester strains that detect base pair substitutions, TA1535 and TA100, as well as in the TA98 frameshift-detector strain. Although positive results were seen with rat liver S9, the hamster liver S9 fraction was more effective in bio-transforming NNP into a reactive mutagen. NNP also induced micronuclei and gene mutations in human lymphoblastoid TK6 cells in the presence of hamster liver S9. Using a panel of TK6 cell lines that each expresses a different human cytochrome P450 (CYP), CYP2C19 was identified as the most active enzyme in the bioactivation of NNP to a genotoxicant among those tested. NNP also induced concentration-dependent DNA strand breakage in metabolically competent 2-dimensional (2D) and 3D cultures of human HepaRG cells. This study indicates that NNP is genotoxic in a variety of bacterial and mammalian systems. Thus, NNP is a mutagenic and genotoxic nitrosamine and a potential human carcinogen.
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Affiliation(s)
- Xilin Li
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA.
| | - Yuan Le
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Ji-Eun Seo
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Xiaoqing Guo
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Yuxi Li
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Si Chen
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Roberta A Mittelstaedt
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Nyosha Moore
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Sharon Guerrero
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Audrey Sims
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Sruthi T King
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Aisar H Atrakchi
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Timothy J McGovern
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Karen L Davis-Bruno
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - David A Keire
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | | | - Robert H Heflich
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Nan Mei
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA.
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Meng F, Mei N, Yan J, Guo X, Richter PA, Chen T, De M. Comparative potency analysis of whole smoke solutions in the bacterial reverse mutation test. Mutagenesis 2021; 36:321-329. [PMID: 34131742 DOI: 10.1093/mutage/geab021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/11/2021] [Indexed: 11/13/2022] Open
Abstract
Short-term in vitro genotoxicity assays are useful tools to assess whether new and emerging tobacco products potentially have reduced toxicity. We previously demonstrated that potency ranking by benchmark dose (BMD) analysis quantitatively identifies differences among several known carcinogens and toxic chemicals representing different chemical classes found in cigarette smoke. In this study, six whole smoke solution (WSS) samples containing both the particulate and gas phases of tobacco smoke were generated from two commercial cigarette brands under different smoking-machine regimens. Sixty test cigarettes of each brand were machine-smoked according to the International Organization for Standardization (ISO) puffing protocol. In addition, either 60 or 20 test cigarettes of each brand were machine-smoked with the Canadian Intense (CI) puffing protocol. All six WSSs were evaluated in the bacterial reverse mutation (Ames) test using Salmonella typhimurium strains, in the presence or absence of S9 metabolic activation. The resulting S9-mediated mutagenic concentration-responses for the four WSSs from 60 cigarettes were then compared using BMD modeling analysis and the mutagenic potency expressed as number of revertants per μl of the WSS. The quantitative approaches resulted in a similar rank order of mutagenic potency for the Ames test in both TA98 and TA100. Under the conditions of this study, these results indicate that quantitative analysis of the Ames test data can discriminate between the mutagenic potencies of WSSs on the basis of smoking-machine regimen (ISO vs. CI), and cigarette product (differences in smoke chemistry).
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Affiliation(s)
- Fanxue Meng
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.,7870 Reflection Cove Dr., Fort Myers, FL, USA
| | - Nan Mei
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Jian Yan
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Xiaoqing Guo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Patricia A Richter
- Division of Nonclinical Science, Center for Tobacco Products, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.,Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Tao Chen
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Mamata De
- Division of Nonclinical Science, Center for Tobacco Products, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
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