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Abdelhady R, Senthong P, Eyers CE, Reamtong O, Cowley E, Cannizzaro L, Stimpson J, Cain K, Wilkinson OJ, Williams NH, Barran PE, Margison GP, Williams DM, Povey AC. Mass Spectrometric Analysis of the Active Site Tryptic Peptide of Recombinant O6-Methylguanine-DNA Methyltransferase Following Incubation with Human Colorectal DNA Reveals the Presence of an O6-Alkylguanine Adductome. Chem Res Toxicol 2023; 36:1921-1929. [PMID: 37983188 PMCID: PMC10731659 DOI: 10.1021/acs.chemrestox.3c00207] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/22/2023]
Abstract
Human exposure to DNA alkylating agents is poorly characterized, partly because only a limited range of specific alkyl DNA adducts have been quantified. The human DNA repair protein, O6-methylguanine O6-methyltransferase (MGMT), irreversibly transfers the alkyl group from DNA O6-alkylguanines (O6-alkGs) to an acceptor cysteine, allowing the simultaneous detection of multiple O6-alkG modifications in DNA by mass spectrometric analysis of the MGMT active site peptide (ASP). Recombinant MGMT was incubated with oligodeoxyribonucleotides (ODNs) containing different O6-alkGs, Temozolomide-methylated calf thymus DNA (Me-CT-DNA), or human colorectal DNA of known O6-MethylG (O6-MeG) levels. It was digested with trypsin, and ASPs were detected and quantified by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. ASPs containing S-methyl, S-ethyl, S-propyl, S-hydroxyethyl, S-carboxymethyl, S-benzyl, and S-pyridyloxobutyl cysteine groups were detected by incubating MGMT with ODNs containing the corresponding O6-alkGs. The LOQ of ASPs containing S-methylcysteine detected after MGMT incubation with Me-CT-DNA was <0.05 pmol O6-MeG per mg CT-DNA. Incubation of MGMT with human colorectal DNA produced ASPs containing S-methylcysteine at levels that correlated with those of O6-MeG determined previously by HPLC-radioimmunoassay (r2 = 0.74; p = 0.014). O6-CMG, a putative O6-hydroxyethylG adduct, and other potential unidentified MGMT substrates were also detected in human DNA samples. This novel approach to the identification and quantitation of O6-alkGs in human DNA has revealed the existence of a human DNA alkyl adductome that remains to be fully characterized. The methodology establishes a platform for characterizing the human DNA O6-alkG adductome and, given the mutagenic potential of O6-alkGs, can provide mechanistic information about cancer pathogenesis.
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Affiliation(s)
- Rasha Abdelhady
- 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, U.K.
| | - Pattama Senthong
- 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, U.K.
| | - Claire E. Eyers
- Department
of Chemistry and Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, U.K.
| | - Onrapak Reamtong
- Department
of Chemistry and Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, U.K.
| | - Elizabeth Cowley
- 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, U.K.
| | - Luca Cannizzaro
- Department
of Chemistry and Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, U.K.
| | - Joanna Stimpson
- Department
of Chemistry and Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, U.K.
| | - Kathleen Cain
- Department
of Chemistry and Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, U.K.
| | - Oliver J. Wilkinson
- Centre
for Chemical Biology, Department of Chemistry, Sheffield Institute
for Nucleic Acids, University of Sheffield, Sheffield S3 7HF, U.K.
| | - Nicholas H. Williams
- Centre
for Chemical Biology, Department of Chemistry, Sheffield Institute
for Nucleic Acids, University of Sheffield, Sheffield S3 7HF, U.K.
| | - Perdita E. Barran
- Department
of Chemistry and Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, U.K.
| | - 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, U.K.
| | - David M. Williams
- Centre
for Chemical Biology, Department of Chemistry, Sheffield Institute
for Nucleic Acids, University of Sheffield, Sheffield S3 7HF, U.K.
| | - 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, U.K.
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2
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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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3
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Geisen SM, Aloisi CMN, Huber SM, Sandell ES, Escher NA, Sturla SJ. Direct Alkylation of Deoxyguanosine by Azaserine Leads to O6-Carboxymethyldeoxyguanosine. Chem Res Toxicol 2021; 34:1518-1529. [PMID: 34061515 DOI: 10.1021/acs.chemrestox.0c00471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The O6-alkylguanosine adduct O6-carboxymethyldeoxyguanosine (O6-CMdG) has been detected at elevated levels in blood and tissue samples from colorectal cancer patients and from healthy volunteers after consuming red meat. The diazo compound l-azaserine leads to the formation of O6-CMdG as well as the corresponding methyl adduct O6-methyldeoxyguanosine (O6-MedG) in cells and is therefore in wide use as a chemical probe in cellular studies concerning DNA damage and mutation. However, there remain knowledge gaps concerning the chemical basis of DNA adduct formation by l-azaserine. To characterize O6-CMdG formation by l-azaserine, we carried out a combination of chemical and enzymatic stability and reactivity studies supported by liquid chromatography tandem mass spectrometry for the simultaneous quantification of O6-CMdG and O6-MedG. We found that l-azaserine is stable under physiological and alkaline conditions as well as in active biological matrices but undergoes acid-catalyzed hydrolysis. We show, for the first time, that l-azaserine reacts directly with guanosine (dG) and oligonucleotides to form an O6-serine-CMdG (O6-Ser-CMdG) adduct. Moreover, by characterizing the reaction of dG with l-azaserine, we demonstrate that O6-Ser-CMdG forms as an intermediate that spontaneously decomposes to form O6-CMdG. Finally, we quantified levels of O6-CMdG and O6-MedG in a human cell line exposed to l-azaserine and found maximal adduct levels after 48 h. The findings of this work elucidate the chemical basis of how l-azaserine reacts with deoxyguanosine and support its use as a chemical probe for N-nitroso compound exposure in carcinogenesis research, particularly concerning the identification of pathways and factors that promote adduct formation.
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Affiliation(s)
- Susanne M Geisen
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Claudia M N Aloisi
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Sabrina M Huber
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Emma S Sandell
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Nora A Escher
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Shana J Sturla
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
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4
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Aloisi CMN, Sandell ES, Sturla SJ. A Chemical Link between Meat Consumption and Colorectal Cancer Development? Chem Res Toxicol 2021; 34:12-23. [PMID: 33417435 DOI: 10.1021/acs.chemrestox.0c00395] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
O6-carboxymethylguanine (O6-CMG) is a mutagenic DNA adduct that forms at increased levels when people eat meat. It has been studied as a potential initiating event in colorectal carcinogenesis. It can arise from alkylation of guanine in DNA by electrophilic degradation products of N-nitroso compounds. There is significant data regarding biochemical and cellular process, including DNA repair and translesion DNA synthesis that control O6-CMG accumulation, persistence, and mutagenicity. Mutation spectra arising from the adduct closely resemble common mutations in colorectal cancer; however, gaps remain in understanding the biochemical processes that regulate how and where the damage persists in the genome. Addressing such questions relies on advances in chemistry such as synthesis approaches and bioanalytical methods. Results of research in this area help advance our understanding of the toxicological relevance of O6-CMG-modified DNA. Further attention should focus on understanding how a combination of genetic and environmental factors control its biological persistence and how this information can be used as a basis of biomoniotoring and prevention efforts to help mitigate colon cancer risk.
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Affiliation(s)
- Claudia M N Aloisi
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Emma S Sandell
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
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5
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Aloisi CMN, Nilforoushan A, Ziegler N, Sturla SJ. Sequence-Specific Quantitation of Mutagenic DNA Damage via Polymerase Amplification with an Artificial Nucleotide. J Am Chem Soc 2020; 142:6962-6969. [PMID: 32196326 PMCID: PMC7192524 DOI: 10.1021/jacs.9b11746] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
![]()
DNA mutations can result from replication
errors due to different
forms of DNA damage, including low-abundance DNA adducts induced by
reactions with electrophiles. The lack of strategies to measure DNA
adducts within genomic loci, however, limits our understanding of
chemical mutagenesis. The use of artificial nucleotides incorporated
opposite DNA adducts by engineered DNA polymerases offers a potential
basis for site-specific detection of DNA adducts, but the availability
of effective artificial nucleotides that insert opposite DNA adducts
is extremely limited, and furthermore, there has been no report of
a quantitative strategy for determining how much DNA alkylation occurs
in a sequence of interest. In this work, we synthesized an artificial
nucleotide triphosphate that is selectively inserted opposite O6-carboxymethyl-guanine DNA by an engineered
polymerase and is required for DNA synthesis past the adduct. We characterized
the mechanism of this enzymatic process and demonstrated that the
artificial nucleotide is a marker for the presence and location in
the genome of O6-carboxymethyl-guanine.
Finally, we established a mass spectrometric method for quantifying
the incorporated artificial nucleotide and obtained a linear relationship
with the amount of O6-carboxymethyl-guanine
in the target sequence. In this work, we present a strategy to identify,
locate, and quantify a mutagenic DNA adduct, advancing tools for linking
DNA alkylation to mutagenesis and for detecting DNA adducts in genes
as potential diagnostic biomarkers for cancer prevention.
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Affiliation(s)
- Claudia M N Aloisi
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Arman Nilforoushan
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Nathalie Ziegler
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
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6
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Seiwert N, Heylmann D, Hasselwander S, Fahrer J. Mechanism of colorectal carcinogenesis triggered by heme iron from red meat. Biochim Biophys Acta Rev Cancer 2019; 1873:188334. [PMID: 31783067 DOI: 10.1016/j.bbcan.2019.188334] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/25/2019] [Accepted: 11/25/2019] [Indexed: 02/07/2023]
Abstract
Colorectal cancer (CRC) is one of the major tumor entities worldwide, with an increasing incidence in younger people. CRC formation is causally linked to various genetic, life-style and dietary risk factors. Among the ladder, the consumption of red meat has emerged as important risk factor contributing to CRC. A large body of evidence shows that heme iron is the critical component of red meat, which promotes colorectal carcinogenesis. In this review, we describe the uptake and cellular fate of both heme and inorganic iron in intestinal epithelial cells. Next, an overview on the DNA damaging properties of heme iron is provided, highlighting the DNA adducts relevant for CRC etiology. Moreover, heme triggered mechanisms leading to colonic hyperproliferation are presented, which are intimately linked to changes in the intestinal microbiota induced by heme. A special focus was set on the impact of heme iron on innate and adaptive immune cells, which could be relevant in the context of CRC. Finally, we recapitulate in vivo studies providing evidence for the tumor-promoting potential of dietary heme iron. Altogether, heme iron affects numerous key pathways involved in the pathogenesis of CRC.
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Affiliation(s)
- Nina Seiwert
- Department of Toxicology, University Medical Center Mainz, 55131 Mainz, Germany; Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany; Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Daniel Heylmann
- Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | | | - Jörg Fahrer
- Department of Toxicology, University Medical Center Mainz, 55131 Mainz, Germany; Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany; Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany.
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7
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McIntyre J. Polymerase iota - an odd sibling among Y family polymerases. DNA Repair (Amst) 2019; 86:102753. [PMID: 31805501 DOI: 10.1016/j.dnarep.2019.102753] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 12/14/2022]
Abstract
It has been two decades since the discovery of the most mutagenic human DNA polymerase, polymerase iota (Polι). Since then, the biochemical activity of this translesion synthesis (TLS) enzyme has been extensively explored, mostly through in vitro experiments, with some insight into its cellular activity. Polι is one of four members of the Y-family of polymerases, which are the best characterized DNA damage-tolerant polymerases involved in TLS. Polι shares some common Y-family features, including low catalytic efficiency and processivity, high infidelity, the ability to bypass some DNA lesions, and a deficiency in 3'→5' exonucleolytic proofreading. However, Polι exhibits numerous properties unique among the Y-family enzymes. Polι has an unusual catalytic pocket structure and prefers Hoogsteen over Watson-Crick pairing, and its replication fidelity strongly depends on the template; further, it prefers Mn2+ ions rather than Mg2+ as catalytic activators. In addition to its polymerase activity, Polι possesses also 5'-deoxyribose phosphate (dRP) lyase activity, and its ability to participate in base excision repair has been shown. As a highly error-prone polymerase, its regulation is crucial and mostly involves posttranslational modifications and protein-protein interactions. The upregulation and downregulation of Polι are correlated with different types of cancer and suggestions regarding the possible function of this polymerase have emerged from studies of various cancer lines. Nonetheless, after twenty years of research, the biological function of Polι certainly remains unresolved.
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Affiliation(s)
- Justyna McIntyre
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5a, 02-106, Warsaw, Poland.
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8
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Du H, Wang P, Li L, Wang Y. Repair and translesion synthesis of O6-alkylguanine DNA lesions in human cells. J Biol Chem 2019; 294:11144-11153. [PMID: 31167778 PMCID: PMC6643039 DOI: 10.1074/jbc.ra119.009054] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/31/2019] [Indexed: 12/15/2022] Open
Abstract
O6-alkyl-2'-deoxyguanosine (O6-alkyl-dG) lesions are among the most mutagenic and prevalent alkylated DNA lesions that are associated with cancer initiation and progression. In this study, using a shuttle vector-based strand-specific PCR-competitive replication and adduct bypass assay in conjunction with tandem MS for product identification, we systematically assessed the repair and replicative bypass of a series of O6-alkyl-dG lesions, with the alkyl group being a Me, Et, nPr, iPr, nBu, iBu, or sBu, in several human cell lines. We found that the extent of replication-blocking effects of these lesions is influenced by the size of the alkyl groups situated on the O6 position of the guanine base. We also noted involvement of distinct DNA repair pathways and translesion synthesis polymerases (Pols) in ameliorating the replication blockage effects elicited by the straight- and branched-chain O6-alkyl-dG lesions. We observed that O6-methylguanine DNA methyltransferase is effective in removing the smaller alkyl groups from the O6 position of guanine, whereas repair of the branched-chain lesions relied on nucleotide excision repair. Moreover, these lesions were highly mutagenic during cellular replication and exclusively directed G→A mutations; Pol η and Pol ζ participated in error-prone bypass of the straight-chain lesions, whereas Pol κ preferentially incorporated the correct dCMP opposite the branched-chain lesions. Together, these results uncover key cellular proteins involved in repair and translesion synthesis of O6-alkyl-dG lesions and provide a better understanding of the roles of these types of lesions in the etiology of human cancer.
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Affiliation(s)
- Hua Du
- Department of Chemistry, University of California, Riverside, California 92521-0403
| | - Pengcheng Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403
| | - Lin Li
- Department of Chemistry, University of California, Riverside, California 92521-0403
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403
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9
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Wang Y, Patil KM, Yan S, Zhang P, Guo W, Wang Y, Chen H, Gillingham D, Huang S. Nanopore Sequencing Accurately Identifies the Mutagenic DNA Lesion O
6
‐Carboxymethyl Guanine and Reveals Its Behavior in Replication. Angew Chem Int Ed Engl 2019; 58:8432-8436. [DOI: 10.1002/anie.201902521] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Indexed: 01/13/2023]
Affiliation(s)
- Yu Wang
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Kiran M. Patil
- Department of ChemistryUniversity of Basel CH-4056 Basel Switzerland
| | - Shuanghong Yan
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Panke Zhang
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Weiming Guo
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Yuqin Wang
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Hong‐Yuan Chen
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Dennis Gillingham
- Department of ChemistryUniversity of Basel CH-4056 Basel Switzerland
| | - Shuo Huang
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
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10
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Wang Y, Patil KM, Yan S, Zhang P, Guo W, Wang Y, Chen H, Gillingham D, Huang S. Nanopore Sequencing Accurately Identifies the Mutagenic DNA Lesion O
6
‐Carboxymethyl Guanine and Reveals Its Behavior in Replication. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Yu Wang
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Kiran M. Patil
- Department of ChemistryUniversity of Basel CH-4056 Basel Switzerland
| | - Shuanghong Yan
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Panke Zhang
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Weiming Guo
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Yuqin Wang
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Hong‐Yuan Chen
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
| | - Dennis Gillingham
- Department of ChemistryUniversity of Basel CH-4056 Basel Switzerland
| | - Shuo Huang
- School of Chemistry and Chemical EngineeringState Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life SciencesNanjing University 210023 China
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11
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Räz MH, Sandell ES, Patil KM, Gillingham DG, Sturla SJ. High Sensitivity of Human Translesion DNA Synthesis Polymerase κ to Variation in O 6-Carboxymethylguanine Structures. ACS Chem Biol 2019; 14:214-222. [PMID: 30645109 DOI: 10.1021/acschembio.8b00802] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Carboxymethylation of DNA, including the formation of the DNA adduct O6-carboxymethylguanine ( O6-CMG), is associated with lifestyle factors, such as diet. It can impede replicative polymerases (Pols) and lead to replication fork stalling, or an alternative means for replication to proceed by translesion DNA synthesis (TLS). TLS requires specialized DNA Pols characterized by open and preformed active sites capable of preferential bypass of alkylated DNA adducts but that have high error rates, leading to mutations. Human TLS Pols can bypass O6-CMG with varying degrees of accuracy, but it is not known how the chemical structure of the O6-CMG adduct influences polymerase proficiency or fidelity. To better understand how adduct structure determines dNTP selection at lesion sites, we prepared DNA templates with a series of O6-CMG structural analogs and compared the primer extension patterns of Y- and X-family Pols in response to these modifications. The results indicate that the structure of the DNA adduct had a striking effect on dNTP selection by Pol κ and that an increased steric size influences the fidelity of Pol η, whereas Pol ι and β function were only marginally affected. To test the hypothesis that specific hydrogen bonding interactions between the templating base and the incoming dNTP are a basis of this selection, we modeled the structural analogs with incoming dNTP in the Pol κ active site. These data indicate that the base pairing geometry and stabilization by a dense hydrogen bonding network are important molecular features for dNTP incorporation, providing a basis for understanding error-free bypass of O6-CMG by Pol κ.
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Affiliation(s)
- Michael H. Räz
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092, Zürich, Switzerland
| | - Emma S. Sandell
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092, Zürich, Switzerland
| | - Kiran M. Patil
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Dennis G. Gillingham
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Shana J. Sturla
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092, Zürich, Switzerland
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12
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Räz MH, Sturla SJ, Gahlon HL. Hydrogen-Bonding Interactions at the DNA Terminus Promote Extension from Methylguanine Lesions by Human Extender DNA Polymerase ζ. Biochemistry 2018; 57:5978-5988. [PMID: 30222325 DOI: 10.1021/acs.biochem.8b00861] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Chemically induced DNA lesions can become DNA replication substrates that are bypassed by low-fidelity DNA polymerases. Following nucleotide misinsertion opposite a DNA lesion, the extension step can contribute to preserving such errors and lead to genomic instability and cancer. DNA polymerase ζ, a B-family polymerase, is proficient as an extender polymerase that catalyzes elongation; however, the chemical factors that impact its DNA replication are not understood. This study addresses the question of how DNA polymerase ζ achieves extension by examining the ability of recombinant human DNA polymerase ζ to extend from a series of methylated guanine lesions. The influence of H-bonding was examined by placing structurally altered nucleoside analogues and canonical bases opposite G, O6-MeG, N1-MeG, and N2-MeG. We determined that terminal base pairs with the highest proclivity for H-bonding were most efficiently extended in both primer extension assays and steady-state kinetic analysis. In contrast, when no H-bonding was possible at the DNA terminus, the least efficient steady-state kinetics were observed. To evaluate H-bonding protein minor groove interactions that may underlie this phenomenon, we performed computational modeling with Escherichia coli DNA polymerase II, a homologue for DNA polymerase ζ. The modeling data together with the primer extension assays demonstrate the importance of having a carbonyl group on the primer strand that can interact with a lysine residue found to be conserved in many B-family polymerases, including human Pol ζ. These data provide a model whereby interbase H-bonding interactions at the DNA terminus promote lesion bypass and extension by human DNA polymerase ζ.
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Affiliation(s)
- Michael H Räz
- Department of Health Sciences and Technology , ETH Zürich , Schmelzbergstrasse 9 , Zürich 8092 , Switzerland
| | - Shana J Sturla
- Department of Health Sciences and Technology , ETH Zürich , Schmelzbergstrasse 9 , Zürich 8092 , Switzerland
| | - Hailey L Gahlon
- Department of Health Sciences and Technology , ETH Zürich , Schmelzbergstrasse 9 , Zürich 8092 , Switzerland
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McKeague M, Otto C, Räz MH, Angelov T, Sturla SJ. The Base Pairing Partner Modulates Alkylguanine Alkyltransferase. ACS Chem Biol 2018; 13:2534-2541. [PMID: 30040894 DOI: 10.1021/acschembio.8b00446] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
O6-Alkylguanine DNA adducts are repaired by the suicide enzyme alkylguanine alkyltransferase (AGT). AGT facilitates repair by binding DNA in the minor groove, flipping out the damaged base, and transferring the O6-alkyl group to a cysteine residue in the enzyme's active site. Despite there being significant knowledge concerning the mechanism of AGT repair, there is limited insight regarding how altered interactions of the adduct with its complementary base in the DNA duplex influence its recognition and repair. In this study, the relationship of base pairing interactions and repair by human AGT (hAGT) was tested in the frequently mutated codon 12 of the KRAS gene with complementary sequences containing each canonical DNA base. The rate of O6-MeG repair decreased 2-fold when O6-MeG was paired with G, whereas all other canonical bases had no impact on the repair rate. We used a combination of biochemical studies, molecular modeling, and artificial nucleobases to elucidate the mechanism accounting for the 2-fold decrease. Our results suggest that the reduced rate of repair is due to O6-MeG adopting a syn conformation about the glycosidic bond precluding the formation of a repair-active complex. These data provide a novel chemical basis for how direct reversion repair may be impeded through modification of the base pair partner and support the use of artificial nucleobases as tools to probe the biochemistry of damage repair processes.
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Affiliation(s)
- Maureen McKeague
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Claudia Otto
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Michael H. Räz
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Todor Angelov
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Shana J. Sturla
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
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14
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Wu J, Wang P, Li L, Williams NL, Ji D, Zahurancik WJ, You C, Wang J, Suo Z, Wang Y. Replication studies of carboxymethylated DNA lesions in human cells. Nucleic Acids Res 2017; 45:7276-7284. [PMID: 28531304 PMCID: PMC5499590 DOI: 10.1093/nar/gkx442] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 05/04/2017] [Indexed: 12/11/2022] Open
Abstract
Metabolic activation of some N-nitroso compounds (NOCs), an important class of DNA damaging agents, can induce the carboxymethylation of nucleobases in DNA. Very little was previously known about how the carboxymethylated DNA lesions perturb DNA replication in human cells. Here, we investigated the effects of five carboxymethylated DNA lesions, i.e. O6-CMdG, N6-CMdA, N4-CMdC, N3-CMdT and O4-CMdT on the efficiency and fidelity of DNA replication in HEK293T human embryonic kidney cells. We found that, while neither N6-CMdA nor N4-CMdC blocked DNA replication or induced mutations, N3-CMdT, O4-CMdT and O6-CMdG moderately blocked DNA replication and induced substantial frequencies of T→A (81%), T→C (68%) and G→A (6.4%) mutations, respectively. In addition, our results revealed that CRISPR-Cas9-mediated depletion of Pol η resulted in significant drops in bypass efficiencies of N4-CMdC and N3-CMdT. Diminution in bypass efficiencies was also observed for N6-CMdA and O6-CMdG upon depletion of Pol κ, and for O6-CMdG upon removal of Pol ζ. Together, our study provided molecular-level insights into the impacts of the carboxymethylated DNA lesions on DNA replication in human cells, revealed the roles of individual translesion synthesis DNA polymerases in bypassing these lesions, and suggested the contributions of O6-CMdG, N3-CMdT and O4-CMdT to the mutations found in p53 gene of human gastrointestinal cancers.
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Affiliation(s)
- Jun Wu
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Pengcheng Wang
- Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521, USA
| | - Lin Li
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Nicole L Williams
- Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521, USA
| | - Debin Ji
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Walter J Zahurancik
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Changjun You
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Jianshuang Wang
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Zucai Suo
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, CA 92521, USA.,Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521, USA
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15
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Malvezzi S, Angelov T, Sturla SJ. Minor Groove 3-Deaza-Adenosine Analogues: Synthesis and Bypass in Translesion DNA Synthesis. Chemistry 2016; 23:1101-1109. [PMID: 27862447 DOI: 10.1002/chem.201604289] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Indexed: 11/07/2022]
Abstract
Anticancer drugs that alkylate DNA in the minor groove may give rise to 3-alkyl-adenosine adducts that interfere with replication, inducing apoptosis in rapidly dividing cancer cells. However, translesion DNA synthesis (TLS) by polymerase enzymes (Pols) with the capacity to bypass DNA adducts may contribute to damage tolerance and drug resistance. 3-Alkyl-adenosine adducts are unstable and depurinate, which is a barrier to addressing chemical and enzymatic aspects of how they impact the progress of DNA Pols. To characterize structure-based relationships of 3-adenine alkylation relevant to cancer drugs on duplex stability and DNA Pol-catalyzed DNA synthesis, we synthesized stable 3-deaza-3-alkyl-adenosine analogues, including 3-deaza-3-phenethyl-adenosine and 3-deaza-3-methoxynaphthylethyl-adenosine, and incorporated them into oligonucleotides. A moderate reduction of duplex stability was observed on the basis of thermal denaturation data. Replication studies using purified Y-family human DNA Pols hPol η, κ, and ι indicated that these enzymes can perform TLS over the modified bases. hPol η had higher misincorporation rates when synthesizing opposite the modified bases compared with adenine, whereas hPol κ and ι maintained high fidelity. These results provide insight into how alterations in chemical structure reduce bypass of minor-groove adducts, and provide novel chemical probes for evaluating minor-groove DNA alkylation.
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Affiliation(s)
- Stefano Malvezzi
- Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092, Zurich, Switzerland
| | - Todor Angelov
- Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092, Zurich, Switzerland
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092, Zurich, Switzerland
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16
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Wyss LA, Nilforoushan A, Williams DM, Marx A, Sturla SJ. The use of an artificial nucleotide for polymerase-based recognition of carcinogenic O6-alkylguanine DNA adducts. Nucleic Acids Res 2016; 44:6564-73. [PMID: 27378785 PMCID: PMC5001614 DOI: 10.1093/nar/gkw589] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 06/20/2016] [Accepted: 06/21/2016] [Indexed: 12/15/2022] Open
Abstract
Enzymatic approaches for locating alkylation adducts at single-base resolution in DNA could enable new technologies for understanding carcinogenesis and supporting personalized chemotherapy. Artificial nucleotides that specifically pair with alkylated bases offer a possible strategy for recognition and amplification of adducted DNA, and adduct-templated incorporation of an artificial nucleotide has been demonstrated for a model DNA adduct O(6)-benzylguanine by a DNA polymerase. In this study, DNA adducts of biological relevance, O(6)-methylguanine (O(6)-MeG) and O(6)-carboxymethylguanine (O(6)-CMG), were characterized to be effective templates for the incorporation of benzimidazole-derived 2'-deoxynucleoside-5'-O-triphosphates ( BENZI: TP and BIM: TP) by an engineered KlenTaq DNA polymerase. The enzyme catalyzed specific incorporation of the artificial nucleotide BENZI: opposite adducts, with up to 150-fold higher catalytic efficiency for O(6)-MeG over guanine in the template. Furthermore, addition of artificial nucleotide BENZI: was required for full-length DNA synthesis during bypass of O(6)-CMG. Selective incorporation of the artificial nucleotide opposite an O(6)-alkylguanine DNA adduct was verified using a novel 2',3'-dideoxy derivative of BENZI: TP. The strategy was used to recognize adducts in the presence of excess unmodified DNA. The specific processing of BENZI: TP opposite biologically relevant O(6)-alkylguanine adducts is characterized herein as a basis for potential future DNA adduct sequencing technologies.
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Affiliation(s)
- Laura A Wyss
- Department of Health Sciences and Technology, ETH Zu¨rich, 8092 Zürich, Switzerland
| | - Arman Nilforoushan
- Department of Health Sciences and Technology, ETH Zu¨rich, 8092 Zürich, Switzerland
| | - David M Williams
- Center for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield, Sheffield S3 7HF, UK
| | - Andreas Marx
- Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zu¨rich, 8092 Zürich, Switzerland
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