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Abstract
DNA damage by chemicals, radiation, or oxidative stress leads to a mutational spectrum, which is complex because it is determined in part by lesion structure, the DNA sequence context of the lesion, lesion repair kinetics, and the type of cells in which the lesion is replicated. Accumulation of mutations may give rise to genetic diseases such as cancer and therefore understanding the process underlying mutagenesis is of immense importance to preserve human health. Chemical or physical agents that cause cancer often leave their mutational fingerprints, which can be used to back-calculate the molecular events that led to disease. To make a clear link between DNA lesion structure and the mutations a given lesion induces, the field of single-lesion mutagenesis was developed. In the last three decades this area of research has seen much growth in several directions, which we attempt to describe in this Perspective.
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Affiliation(s)
- Ashis K Basu
- Department of Chemistry, The University of Connecticut Storrs, Storrs, Connecticut 06269, United States
| | - John M Essigmann
- Departments of Chemistry, Biological Engineering and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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2
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Bienstock RJ, Perera L, Pasquinelli MA. Molecular Modeling Study of the Genotoxicity of the Sudan I and Sudan II Azo Dyes and Their Metabolites. Front Chem 2022; 10:880782. [PMID: 35815205 PMCID: PMC9261194 DOI: 10.3389/fchem.2022.880782] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
Azo dyes are defined by the presence of a characteristic N=N group. Sudan I and Sudan II are synthetic azo dyes that have been used as coloring agents. Although animal toxicity studies suggest that Sudan dyes are mutagenic, their molecular mechanism of action is unknown, thus making it challenging to establish thresholds for tolerable daily intake or to understand how these molecules could be modified to ameliorate toxicity. In addition, dye metabolites, such as azobiphenyl and 4-aminobiphenyl, have been correlated with epigenetic alterations. We shed some light on the mechanisms of Sudan dye genotoxicity through a molecular modeling study of Sudan I and Sudan II dyes and two common metabolites interacting with DNA as adducts. The results suggest that all four adducts cause significant perturbations to the DNA helical conformation and structure; thus, it can be inferred that DNA repair and replication processes would be significantly impacted.
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Affiliation(s)
- Rachelle J. Bienstock
- Fiber and Polymer Science Program, Wilson College of Textiles, North Carolina State University, Raleigh, NC, United States
- National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, United States
| | - Lalith Perera
- National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, United States
- *Correspondence: Lalith Perera, ; Melissa A. Pasquinelli,
| | - Melissa A. Pasquinelli
- Fiber and Polymer Science Program, Wilson College of Textiles, North Carolina State University, Raleigh, NC, United States
- Forest Biomaterials, College of Natural Resources, North Carolina State University, Raleigh, NC, United States
- *Correspondence: Lalith Perera, ; Melissa A. Pasquinelli,
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3
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Kathuria P, Singh P, Sharma P, Manderville RA, Wetmore SD. Molecular Dynamics Study of One-Base Deletion Duplexes Containing the Major DNA Adduct Formed by Ochratoxin A: Effects of Sequence Context and Adduct Ionization State on Lesion Site Structure and Mutagenicity. J Phys Chem B 2019; 123:6980-6989. [PMID: 31311268 DOI: 10.1021/acs.jpcb.9b06489] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Ochratoxin A (OTA) is a ubiquitous food toxin associated with chronic nephropathy in humans and renal carcinogenicity in rodents. The mutational spectra of cells exposed to OTA reveal that one-base deletions comprise the largest percentage (73%) of the total mutations that occur upon OTA exposure. To contribute toward understanding the prevalence of OTA-induced one-base deletion mutations, the present work uses molecular dynamics (MD) simulations to analyze the conformational preferences of one-base deletion duplexes containing OT-G, the major OTA adduct (addition product) at the C8-site of guanine. Specifically, the influence of OT-G in four possible ionization states and three sequence contexts (G1, G2 and G3 in the NarI (5'-G1G2CG3CC-3'), a prokaryotic mutational hotspot sequence) on the structure of the adducted DNA is investigated. Our data reveal that the damaged helices are stable in two (B-type (B) and stacked (S)) conformations that are structurally similar to those adopted by common N-linked C8-guanine lesions. However, the adduct ionization state and sequence context affect the degree of helical distortion and the B/S conformational heterogeneity, which will impact the lesion repair and replication outcomes. This finding correlates with the experimentally reported tissue-specific mutagenicity of OTA exposure. Furthermore, regardless of the adduct conformation, ionization state, or sequence context, more stable lesion-site interactions and lack of disruption of the flanking base pairs in the one-base deletion duplexes compared to the corresponding two-base deletion helices rationalize the greater abundance of OTA induced one-base deletions. Overall, our work provides valuable structural insights that help explain the experimentally observed mutagenicity associated with OTA.
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Affiliation(s)
- Preetleen Kathuria
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry , Panjab University , Chandigarh 160014 , India
| | - Prebhleen Singh
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry , Panjab University , Chandigarh 160014 , India
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry , Panjab University , Chandigarh 160014 , India
| | - Richard A Manderville
- Departments of Chemistry and Toxicology , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry , University of Lethbridge , Lethbridge , Alberta T1K 3M4 , Canada
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4
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Berger FD, Manderville RA, Sturla SJ. Adduct Fluorescence as a Tool to Decipher Sequence Impact on Frameshift Mutations Mediated by a C-Linked C8-Biphenyl-Guanine Lesion. Chem Res Toxicol 2019; 32:784-791. [PMID: 30785283 DOI: 10.1021/acs.chemrestox.9b00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aromatic chemicals can undergo metabolic activation to afford electrophilic species that react at the C8-site of 2'-deoxyguanosine (dG) to generate bulky C8-dG adducts as a basis of initiating carcinogenesis. These DNA lesions have served as models to understand the mechanism of frameshift mutagenesis, especially within CG-dinucleotide repeat sequences, such as NarI (5'-GGCXCC-3', where X = C8-dG adduct), however there is still limited capacity to predict the likelihood of mutation arising within particular contexts, and hence chemistry-based strategies are needed for probing relationships between nucleic acid sequence and structure with replication errors. In the NarI sequence, certain C8-dG adducts may trigger in the course of DNA synthesis the formation of a slipped mutagenic intermediate (SMI) that contains a two nucleotide (XC) bulge in the template strand that can form upstream of the polymerase active site. This distortion facilitates polymerization but affords a GC dinucleotide deletion product (-2 frameshift mutation). In the current study, incorporating the fluorescent C-linked 4-fluorobiphenyl-dG (FBP-dG) adduct into two 22-mer templates containing CG-dinucleotide repeats ( NarI: 3'-CXCGGC-5' and CG3: 3'-CXCGCG-5', X = FBP-dG) and performing primer extension reactions using DNA polymerase I, Klenow fragment exo- (Kf-) revealed a dramatic sequence-based difference in polymerase bypass efficiency. Primer extension past FBP-dG within the NarI sequence was strongly blocked, whereas Kf- extended the primer past FBP-dG within a CG3 template to afford a full-length product and the GC dinucleotide deletion. To model the nucleotide insertion steps in the fully paired (FP) versus the slipped mutagenic (SM) translesion pathways, adducted template:primer duplexes were constructed and characterized by UV thermal denaturation and fluorescence spectroscopy. The emission intensity of the FBP-dG lesion exhibits sensitivity to SMI formation (turn-on) versus a FP duplex (turn-off), permitting insight into adduct base-pairing within the template:primer duplexes. This fluorescence sensitivity provides a rationale for sequence impact on -2 frameshift mutations mediated by the C-linked FBP-dG lesion.
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Affiliation(s)
- Florence D Berger
- Department of Health Sciences and Technology , ETH Zurich , 8092 Zurich , Switzerland
| | - Richard A Manderville
- Departments of Chemistry and Toxicology , University of Guelph , Guelph , Ontario , Canada N1G 2W1
| | - Shana J Sturla
- Department of Health Sciences and Technology , ETH Zurich , 8092 Zurich , Switzerland
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5
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Ma B, Stepanov I, Hecht SS. Recent Studies on DNA Adducts Resulting from Human Exposure to Tobacco Smoke. TOXICS 2019; 7:E16. [PMID: 30893918 PMCID: PMC6468371 DOI: 10.3390/toxics7010016] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/09/2019] [Accepted: 03/13/2019] [Indexed: 12/22/2022]
Abstract
DNA adducts are believed to play a central role in the induction of cancer in cigarette smokers and are proposed as being potential biomarkers of cancer risk. We have summarized research conducted since 2012 on DNA adduct formation in smokers. A variety of DNA adducts derived from various classes of carcinogens, including aromatic amines, polycyclic aromatic hydrocarbons, tobacco-specific nitrosamines, alkylating agents, aldehydes, volatile carcinogens, as well as oxidative damage have been reported. The results are discussed with particular attention to the analytical methods used in those studies. Mass spectrometry-based methods that have higher selectivity and specificity compared to 32P-postlabeling or immunochemical approaches are preferred. Multiple DNA adducts specific to tobacco constituents have also been characterized for the first time in vitro or detected in vivo since 2012, and descriptions of those adducts are included. We also discuss common issues related to measuring DNA adducts in humans, including the development and validation of analytical methods and prevention of artifact formation.
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Affiliation(s)
- Bin Ma
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Irina Stepanov
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Stephen S Hecht
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA.
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Kathuria P, Sharma P, Manderville RA, Wetmore SD. Molecular Dynamics Simulations of Mismatched DNA Duplexes Associated with the Major C8-Linked 2′-Deoxyguanosine Adduct of the Food Mutagen Ochratoxin A: Influence of Opposing Base, Adduct Ionization State, and Sequence on the Structure of Damaged DNA. Chem Res Toxicol 2018; 31:712-720. [DOI: 10.1021/acs.chemrestox.8b00064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Preetleen Kathuria
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Richard A. Manderville
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Stacey D. Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
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Berger FD, Sturla SJ, Kung RW, Montina T, Wetmore SD, Manderville RA. Conformational Preference and Fluorescence Response of a C-Linked C8-Biphenyl-Guanine Lesion in the NarI Mutational Hotspot: Evidence for Enhanced Syn Adduct Formation. Chem Res Toxicol 2017; 31:37-47. [DOI: 10.1021/acs.chemrestox.7b00266] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Florence D. Berger
- Department
of Health Sciences and Technology, Institute of Food, Nutrition, and
Health, ETH Zürich, 8092 Zürich, Switzerland
| | - Shana J. Sturla
- Department
of Health Sciences and Technology, Institute of Food, Nutrition, and
Health, ETH Zürich, 8092 Zürich, Switzerland
| | - Ryan W. Kung
- Department
of Chemistry and Biochemistry, and the Canadian Centre for Research
in Advanced Fluorine Technologies, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Tony Montina
- Department
of Chemistry and Biochemistry, and the Canadian Centre for Research
in Advanced Fluorine Technologies, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Stacey D. Wetmore
- Department
of Chemistry and Biochemistry, and the Canadian Centre for Research
in Advanced Fluorine Technologies, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Richard A. Manderville
- Departments
of Chemistry and Toxicology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Kathuria P, Sharma P, Manderville RA, Wetmore SD. Molecular Modeling of the Major DNA Adduct Formed from Food Mutagen Ochratoxin A in NarI Two-Base Deletion Duplexes: Impact of Sequence Context and Adduct Ionization on Conformational Preference and Mutagenicity. Chem Res Toxicol 2017; 30:1582-1591. [PMID: 28719194 DOI: 10.1021/acs.chemrestox.7b00103] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Exposure to ochratoxin A (OTA), a possible human carcinogen, leads to many different DNA mutations. As a first step toward understanding the structural basis of OTA-induced mutagenicity, the present work uses a robust computational approach and a slipped mutagenic intermediate model previously studied for C8-dG aromatic amine adducts to analyze the conformational features of postreplication two-base deletion DNA duplexes containing OT-dG, the major OTA lesion at the C8 position of guanine. Specifically, a total of 960 ns of molecular dynamics simulations (excluding trial simulations) were carried out on four OT-dG ionization states in three sequence contexts within oligomers containing the NarI recognition sequence, a known hotspot for deletion mutations induced by related adducts formed from known carcinogens. Our results indicate that the structural properties and relative stability of the competing "major groove" and "stacked" conformations of OTA adducted two-base deletion duplexes depend on both the OTA ionization state and the sequence context, mainly due to conformation-dependent deviations in discrete local (hydrogen-bonding and stacking) interactions at the lesion site, as well as DNA bending. When the structural characteristics of the OT-dG adducted two-base deletion duplexes are compared to those associated with previously studied C8-dG adducts, a greater understanding of the effects of the nucleobase-carcinogen linkage, and size of the carcinogenic moiety on the conformational preferences of damaged DNA is obtained. Most importantly, our work predicts key structural features for OT-dG-adducted deletion DNA duplexes, which in turn allow us to develop hypotheses regarding OT-dG replication outcomes. Thus, our computational results are valuable for the design and interpretation of future biochemical studies on the potentially carcinogenic OT-dG lesion.
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Affiliation(s)
- Preetleen Kathuria
- Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University , Chandigarh 160014, India
| | - Purshotam Sharma
- Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University , Chandigarh 160014, India
| | - Richard A Manderville
- Departments of Chemistry and Toxicology, University of Guelph , Guelph, Ontario N1G 2W1, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge , Lethbridge, Alberta T1K 3M4, Canada
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