1
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Hsiao YC, Matulewicz RS, Sherman SE, Jaspers I, Weitzman ML, Gordon T, Liu CW, Yang Y, Lu K, Bjurlin MA. Untargeted Metabolomics to Characterize the Urinary Chemical Landscape of E-Cigarette Users. Chem Res Toxicol 2023; 36:630-642. [PMID: 36912507 PMCID: PMC10371198 DOI: 10.1021/acs.chemrestox.2c00346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
The health and safety of using e-cigarette products (vaping) have been challenging to assess and further regulate due to their complexity. Inhaled e-cigarette aerosols contain chemicals with under-recognized toxicological profiles, which could influence endogenous processes once inhaled. We urgently need more understanding on the metabolic effects of e-cigarette exposure and how they compare to combustible cigarettes. To date, the metabolic landscape of inhaled e-cigarette aerosols, including chemicals originated from vaping and perturbed endogenous metabolites in vapers, is poorly characterized. To better understand the metabolic landscape and potential health consequences of vaping, we applied liquid chromatography-mass spectrometry (LC-MS) based nontargeted metabolomics to analyze compounds in the urine of vapers, cigarette smokers, and nonusers. Urine from vapers (n = 34), smokers (n = 38), and nonusers (n = 45) was collected for verified LC-HRMS nontargeted chemical analysis. The altered features (839, 396, and 426 when compared smoker and control, vaper and control, and smoker and vaper, respectively) among exposure groups were deciphered for their structural identities, chemical similarities, and biochemical relationships. Chemicals originating from e-cigarettes and altered endogenous metabolites were characterized. There were similar levels of nicotine biomarkers of exposure among vapers and smokers. Vapers had higher urinary levels of diethyl phthalate and flavoring agents (e.g., delta-decalactone). The metabolic profiles featured clusters of acylcarnitines and fatty acid derivatives. More consistent trends of elevated acylcarnitines and acylglycines in vapers were observed, which may suggest higher lipid peroxidation. Our approach in monitoring shifts of the urinary chemical landscape captured distinctive alterations resulting from vaping. Our results suggest similar nicotine metabolites in vapers and cigarette smokers. Acylcarnitines are biomarkers of inflammatory status and fatty acid oxidation, which were dysregulated in vapers. With higher lipid peroxidation, radical-forming flavoring, and higher level of specific nitrosamine, we observed a trend of elevated cancer-related biomarkers in vapers as well. Together, these data present a comprehensive profiling of urinary biochemicals that were dysregulated due to vaping.
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Affiliation(s)
- Yun-Chung Hsiao
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599
| | - Richard S. Matulewicz
- Department of Surgery, Urology Service, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Scott E. Sherman
- Section on Tobacco, Alcohol and Drug Use, Department of Population Health, NYU School of Medicine, New York, NY 07920
| | - Ilona Jaspers
- Curriculum in Toxicology & Environmental Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599
- Center for Environmental Medicine, Asthma and Lung Biology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599
- Department of Pediatrics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Michael L. Weitzman
- Department of Pediatrics, New York University School of Medicine, New York, NY 10016
| | - Terry Gordon
- Department of Environmental Medicine, New York University School of Medicine, New York, NY 10016
| | - Chih-Wei Liu
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599
| | - Yifei Yang
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599
| | - Kun Lu
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599
| | - Marc A. Bjurlin
- Department of Urology, University of North Carolina, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
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2
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Li Y, Hecht SS. Metabolic Activation and DNA Interactions of Carcinogenic N-Nitrosamines to Which Humans Are Commonly Exposed. Int J Mol Sci 2022; 23:ijms23094559. [PMID: 35562949 PMCID: PMC9105260 DOI: 10.3390/ijms23094559] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 02/04/2023] Open
Abstract
Carcinogenic N-nitrosamine contamination in certain drugs has recently caused great concern and the attention of regulatory agencies. These carcinogens-widely detectable in relatively low levels in food, water, cosmetics, and drugs-are well-established and powerful animal carcinogens. The electrophiles resulting from the cytochrome P450-mediated metabolism of N-nitrosamines can readily react with DNA and form covalent addition products (DNA adducts) that play a central role in carcinogenesis if not repaired. In this review, we aim to provide a comprehensive and updated review of progress on the metabolic activation and DNA interactions of 10 carcinogenic N-nitrosamines to which humans are commonly exposed. Certain DNA adducts such as O6-methylguanine with established miscoding properties play central roles in the cancer induction process, whereas others have been linked to the high incidence of certain types of cancers. We hope the data summarized here will help researchers gain a better understanding of the bioactivation and DNA interactions of these 10 carcinogenic N-nitrosamines and facilitate further research on their toxicologic and carcinogenic properties.
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Affiliation(s)
- Yupeng Li
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
- Correspondence: ; Tel.: +1-612-624-8187
| | - Stephen S. Hecht
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
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3
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Pujari SS, Jokipii Krueger CC, Chao C, Hutchins S, Hurben AK, Boysen G, Tretyakova N. DEB-FAPy-dG Adducts of 1,3-Butadiene: Synthesis, Structural Characterization, and Formation in 1,2,3,4-Diepoxybutane Treated DNA. Chemistry 2022; 28:e202103245. [PMID: 34767297 PMCID: PMC10603587 DOI: 10.1002/chem.202103245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Indexed: 11/10/2022]
Abstract
Metabolic activation of the human carcinogen 1,3-butadiene (BD) by cytochrome 450 monooxygenases gives rise to a genotoxic diepoxide, 1,2,3,4-diepoxybutane (DEB). This reactive electrophile alkylates guanine bases in DNA to produce N7-(2-hydroxy-3,4-epoxy-1-yl)-dG (N7-DE-dG) adducts. Because of the positive charge at the N7 position of the purine heterocycle, N7-DEB-dG adducts are inherently unstable and can undergo spontaneous depurination or base-catalyzed imidazole ring opening to give N6 -[2-deoxy-D-erythro-pentofuranosyl]-2,6-diamino-3,4-dihydro-4-oxo-5-N-1-(oxiran-2-yl)propan-1-ol-formamidopyrimidine (DEB-FAPy-dG) adducts. Here we report the first synthesis and structural characterization of DEB-FAPy-dG adducts. Authentic standards of DEB-FAPy-dG and its 15 N3 -labeled analogue were used for the development of a quantitative nanoLC-ESI+ -HRMS/MS method, allowing for adduct detection in DEB-treated calf thymus DNA. DEB-FAPy-dG formation in DNA was dependent on DEB concentration and pH, with higher numbers observed under alkaline conditions.
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Affiliation(s)
- Suresh S Pujari
- Department of Medicinal Chemistry, College of Pharmacy, Cancer and Cardiovascular Research Building, University of Minnesota, 2231 6th Street SE, Minneapolis, MN, 55455, USA
| | - Caitlin C Jokipii Krueger
- Department of Medicinal Chemistry, College of Pharmacy, Cancer and Cardiovascular Research Building, University of Minnesota, 2231 6th Street SE, Minneapolis, MN, 55455, USA
| | - Christopher Chao
- Department of Medicinal Chemistry, College of Pharmacy, Cancer and Cardiovascular Research Building, University of Minnesota, 2231 6th Street SE, Minneapolis, MN, 55455, USA
| | - Spencer Hutchins
- Department of Medicinal Chemistry, College of Pharmacy, Cancer and Cardiovascular Research Building, University of Minnesota, 2231 6th Street SE, Minneapolis, MN, 55455, USA
| | - Alexander K Hurben
- Department of Medicinal Chemistry, College of Pharmacy, Cancer and Cardiovascular Research Building, University of Minnesota, 2231 6th Street SE, Minneapolis, MN, 55455, USA
| | - Gunnar Boysen
- Department of Environmental and Occupational Health and the Winthrop P Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 West Markham St., Slot 820, Little Rock, AR, 72205, USA
| | - Natalia Tretyakova
- Department of Medicinal Chemistry, College of Pharmacy, Cancer and Cardiovascular Research Building, University of Minnesota, 2231 6th Street SE, Minneapolis, MN, 55455, USA
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4
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Bacurio JHT, Yang H, Naldiga S, Powell BV, Ryan BJ, Freudenthal BD, Greenberg MM, Basu AK. Sequence context effects of replication of Fapy•dG in three mutational hot spot sequences of the p53 gene in human cells. DNA Repair (Amst) 2021; 108:103213. [PMID: 34464900 DOI: 10.1016/j.dnarep.2021.103213] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 01/01/2023]
Abstract
Fapy•dG and 8-OxodGuo are formed in DNA from a common N7-dG radical intermediate by reaction with hydroxyl radical. Although cellular levels of Fapy•dG are often greater, its effects on replication are less well understood than those of 8-OxodGuo. In this study plasmid DNA containing Fapy•dG in three mutational hotspots of human cancers, codons 248, 249, and 273 of the p53 tumor suppressor gene, was replicated in HEK 293T cells. TLS efficiencies for the Fapy•dG containing plasmids varied from 72 to 89%, and were further reduced in polymerase-deficient cells. The mutation frequency (MF) of Fapy•dG ranged from 7.3 to 11.6%, with G→T and G→A as major mutations in codons 248 and 249 compared to primarily G→T in codon 273. Increased MF in hPol ι-, hPol κ-, and hPol ζ-deficient cells suggested that these polymerases more frequently insert the correct nucleotide dC opposite Fapy•dG, whereas decreased G→A in codons 248 and 249 and reduction of all mutations in codon 273 in hPol λ-deficient cells indicated hPol λ's involvement in Fapy•dG mutagenesis. In vitro kinetic analysis using isolated translesion synthesis polymerases and hPol λ incompletely corroborated the mutagenesis experiments, indicating codependence on other proteins in the cellular milieu. In conclusion, Fapy•dG mutagenesis is dependent on the DNA sequence context, but its bypass by the TLS polymerases is largely error-free.
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Affiliation(s)
| | - Haozhe Yang
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Spandana Naldiga
- Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA
| | - Brent V Powell
- Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA
| | - Benjamin J Ryan
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Marc M Greenberg
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA.
| | - Ashis K Basu
- Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA.
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5
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Koag MC, Jung H, Kou Y, Lee S. Bypass of the Major Alkylative DNA Lesion by Human DNA Polymerase η. Molecules 2019; 24:molecules24213928. [PMID: 31683505 PMCID: PMC6864850 DOI: 10.3390/molecules24213928] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 01/13/2023] Open
Abstract
A wide range of endogenous and exogenous alkylating agents attack DNA to generate various alkylation adducts. N7-methyl-2-deoxyguanosine (Fm7dG) is the most abundant alkylative DNA lesion. If not repaired, Fm7dG can undergo spontaneous depurination, imidazole ring-opening, or bypass by translesion synthesis DNA polymerases. Human DNA polymerase η (polη) efficiently catalyzes across Fm7dG in vitro, but its structural basis is unknown. Herein, we report a crystal structure of polη in complex with templating Fm7dG and an incoming nonhydrolyzable dCTP analog, where a 2'-fluorine-mediated transition destabilization approach was used to prevent the spontaneous depurination of Fm7dG. The structure showed that polη readily accommodated the Fm7dG:dCTP base pair with little conformational change of protein and DNA. In the catalytic site, Fm7dG and dCTP formed three hydrogen bonds with a Watson-Crick geometry, indicating that the major keto tautomer of Fm7dG is involved in base pairing. The polη-Fm7dG:dCTP structure was essentially identical to the corresponding undamaged structure, which explained the efficient bypass of the major methylated lesion. Overall, the first structure of translesion synthesis DNA polymerase bypassing Fm7dG suggests that in the catalytic site of Y-family DNA polymerases, small N7-alkylguanine adducts may be well tolerated and form the canonical Watson-Crick base pair with dCTP through their keto tautomers.
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Affiliation(s)
- Myong-Chul Koag
- The Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, 2409 University Avenue, TX 78712, USA.
| | - Hunmin Jung
- The Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, 2409 University Avenue, TX 78712, USA.
| | - Yi Kou
- The Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, 2409 University Avenue, TX 78712, USA.
| | - Seongmin Lee
- The Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, 2409 University Avenue, TX 78712, USA.
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6
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Njuma OJ, Su Y, Guengerich FP. The abundant DNA adduct N 7-methyl deoxyguanosine contributes to miscoding during replication by human DNA polymerase η. J Biol Chem 2019; 294:10253-10265. [PMID: 31101656 DOI: 10.1074/jbc.ra119.008986] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 05/16/2019] [Indexed: 12/14/2022] Open
Abstract
Aside from abasic sites and ribonucleotides, the DNA adduct N 7-methyl deoxyguanosine (N7 -CH3 dG) is one of the most abundant lesions in mammalian DNA. Because N7 -CH3 dG is unstable, leading to deglycosylation and ring-opening, its miscoding potential is not well-understood. Here, we employed a 2'-fluoro isostere approach to synthesize an oligonucleotide containing an analog of this lesion (N7 -CH3 2'-F dG) and examined its miscoding potential with four Y-family translesion synthesis DNA polymerases (pols): human pol (hpol) η, hpol κ, and hpol ι and Dpo4 from the archaeal thermophile Sulfolobus solfataricus We found that hpol η and Dpo4 can bypass the N7 -CH3 2'-F dG adduct, albeit with some stalling, but hpol κ is strongly blocked at this lesion site, whereas hpol ι showed no distinction with the lesion and the control templates. hpol η yielded the highest level of misincorporation opposite the adduct by inserting dATP or dTTP. Moreover, hpol η did not extend well past an N 7-CH3 2'-F dG:dT mispair. MS-based sequence analysis confirmed that hpol η catalyzes mainly error-free incorporation of dC, with misincorporation of dA and dG in 5-10% of products. We conclude that N 7-CH3 2'-F dG and, by inference, N 7-CH3 dG have miscoding and mutagenic potential. The level of misincorporation arising from this abundant adduct can be considered as potentially mutagenic as a highly miscoding but rare lesion.
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Affiliation(s)
- Olive J Njuma
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146
| | - Yan Su
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146
| | - F Peter Guengerich
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146
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7
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Groehler AS, Najjar D, Pujari SS, Sangaraju D, Tretyakova NY. N 6-(2-Deoxy-d- erythro-pentofuranosyl)-2,6-diamino-3,4-dihydro-4-oxo-5- N-(2-hydroxy-3-buten-1-yl)-formamidopyrimidine Adducts of 1,3-Butadiene: Synthesis, Structural Identification, and Detection in Human Cells. Chem Res Toxicol 2018; 31:885-897. [PMID: 30016111 DOI: 10.1021/acs.chemrestox.8b00123] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
1,3-Butadiene (BD) is an environmental and occupational toxicant classified as a human carcinogen. BD is metabolically activated by cytochrome P450 monooxygenases to 3,4-epoxy-1-butene (EB), which alkylates DNA to form a range of nucleobase adducts. Among these, the most abundant are the hydrolytically labile N7-guanine adducts such as N7-(2-hydroxy-3-buten-1-yl)-guanine (N7-EB-dG). We now report that N7-EB-dG can be converted to the corresponding ring open N6-(2-deoxy-d- erythro-pentofuranosyl)-2,6-diamino-3,4-dihydro-4-oxo-5- N-(2-hydroxy-3-buten-1-yl)-formamidopyrimidine (EB-Fapy-dG) adducts. EB-Fapy-dG lesions were detected in EB-treated calf thymus DNA and in EB-treated mammalian cells using quantitative isotope dilution nanoLC-ESI+-MS/MS. EB-Fapy-dG adduct formation in EB-treated calf thymus DNA was concentration dependent and was greatly accelerated at an increased pH. EB-FAPy-dG adduct amounts were 2-fold higher in base excision repair-deficient NEIL1-/- mouse embryonic fibroblasts (MEF) as compared to isogenic controls (NEIL1+/+), suggesting that this lesion may be a substrate for NEIL1. Furthermore, NEIL1-/- cells were sensitized to EB treatment as compared to NEIL1+/+ fibroblasts. Overall, our results indicate that ring-opened EB-FAPy-dG adducts form under physiological conditions, prompting future studies to determine their contributions to genotoxicity and mutagenicity of BD.
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Affiliation(s)
- Arnold S Groehler
- Department of Medicinal Chemistry and Masonic Cancer Center , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Dominic Najjar
- Department of Medicinal Chemistry and Masonic Cancer Center , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Suresh S Pujari
- Department of Medicinal Chemistry and Masonic Cancer Center , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Dewakar Sangaraju
- Department of Medicinal Chemistry and Masonic Cancer Center , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Natalia Y Tretyakova
- Department of Medicinal Chemistry and Masonic Cancer Center , University of Minnesota , Minneapolis , Minnesota 55455 , United States
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8
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Bamberger SN, Malik CK, Voehler MW, Brown SK, Pan H, Johnson-Salyard TL, Rizzo CJ, Stone MP. Configurational and Conformational Equilibria of N 6-(2-Deoxy-d-erythro-pentofuranosyl)-2,6-diamino-3,4-dihydro-4-oxo-5- N-methylformamidopyrimidine (MeFapy-dG) Lesion in DNA. Chem Res Toxicol 2018; 31:924-935. [PMID: 30169026 DOI: 10.1021/acs.chemrestox.8b00135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The most common lesion in DNA occurring due to clinical treatment with Temozolomide or cellular exposures to other methylating agents is 7-methylguanine (N7-Me-dG). It can undergo a secondary reaction to form N6-(2-deoxy-d-erythro-pentofuranosyl)-2,6-diamino-3,4-dihydro-4-oxo-5- N-methylformamidopyrimidine (MeFapy-dG). MeFapy-dG undergoes epimerization in DNA to produce either α or β deoxyribose anomers. Additionally, conformational rotation around the formyl bond, C5- N5 bond, and glycosidic bond may occur. To characterize and quantitate the mixture of these isomers in DNA, a 13C-MeFapy-dG lesion, in which the CH3 group of the MeFapy-dG was isotopically labeled, was incorporated into the trimer 5'-TXT-3' and the dodecamer 5'-CATXATGACGCT-3' (X = 13C-MeFapy-dG). NMR spectroscopy of both the trimer and dodecamer revealed that the MeFapy-dG lesion exists in single strand DNA as ten configurationally and conformationally discrete species, eight of which may be unequivocally assigned. In the duplex dodecamer, the MeFapy-dG lesion exists as six configurationally and conformationally discrete species. Analyses of NMR data in the single strand trimer confirm that for each deoxyribose anomer, atropisomerism occurs around the C5- N5 bond to produce R a and S a atropisomers. Each atropisomer exhibits geometrical isomerism about the formyl bond yielding E and Z conformations. 1H NMR experiments allow the relative abundances of the species to be determined. For the single strand trimer, the α and β anomers exist in a 3:7 ratio, favoring the β anomer. For the β anomer, with respect to the C5- N5 bond, the R a and S a atropisomers are equally populated. However, the Z geometrical isomer of the formyl moiety is preferred. For the α anomer, the E- S a isomer is present at 12%, whereas all other isomers are present at 5-7%. DNA processing enzymes may differentially recognize different isomers of the MeFapy-dG lesion. Moreover, DNA sequence-specific differences in the populations of configurational and conformational species may modulate biological responses to the MeFapy-dG lesion.
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Affiliation(s)
- Stephanie N Bamberger
- Department of Chemistry , Vanderbilt University Center for Structural Biology, Vanderbilt Center in Molecular Toxicology, and the Vanderbilt-Ingram Cancer Center, Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Chanchal K Malik
- Department of Chemistry , Vanderbilt University Center for Structural Biology, Vanderbilt Center in Molecular Toxicology, and the Vanderbilt-Ingram Cancer Center, Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Markus W Voehler
- Department of Chemistry , Vanderbilt University Center for Structural Biology, Vanderbilt Center in Molecular Toxicology, and the Vanderbilt-Ingram Cancer Center, Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Summer K Brown
- Department of Chemistry , Vanderbilt University Center for Structural Biology, Vanderbilt Center in Molecular Toxicology, and the Vanderbilt-Ingram Cancer Center, Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Hope Pan
- Department of Chemistry , Vanderbilt University Center for Structural Biology, Vanderbilt Center in Molecular Toxicology, and the Vanderbilt-Ingram Cancer Center, Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Tracy L Johnson-Salyard
- Department of Chemistry , Vanderbilt University Center for Structural Biology, Vanderbilt Center in Molecular Toxicology, and the Vanderbilt-Ingram Cancer Center, Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Carmelo J Rizzo
- Department of Chemistry , Vanderbilt University Center for Structural Biology, Vanderbilt Center in Molecular Toxicology, and the Vanderbilt-Ingram Cancer Center, Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Michael P Stone
- Department of Chemistry , Vanderbilt University Center for Structural Biology, Vanderbilt Center in Molecular Toxicology, and the Vanderbilt-Ingram Cancer Center, Vanderbilt University , Nashville , Tennessee 37235 , United States
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9
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Minko IG, Rizzo CJ, Lloyd RS. Mutagenic potential of nitrogen mustard-induced formamidopyrimidine DNA adduct: Contribution of the non-canonical α-anomer. J Biol Chem 2017; 292:18790-18799. [PMID: 28972137 DOI: 10.1074/jbc.m117.802520] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/15/2017] [Indexed: 12/14/2022] Open
Abstract
Nitrogen mustards (NMs) are DNA-alkylating compounds that represent the earliest anticancer drugs. However, clinical use of NMs is limited because of their own mutagenic properties. The mechanisms of NM-induced mutagenesis remain unclear. The major product of DNA alkylation by NMs is a cationic NM-N7-dG adduct that can yield the imidazole ring-fragmented lesion, N5-NM-substituted formamidopyrimidine (NM-Fapy-dG). Characterization of this adduct is complicated because it adopts different conformations, including both a canonical β- and an unnatural α-anomeric configuration. Although formation of NM-Fapy-dG in cellular DNA has been demonstrated, its potential role in NM-induced mutagenesis is unknown. Here, we created site-specifically modified single-stranded vectors for replication in primate (COS7) or Escherichia coli cells. In COS7 cells, NM-Fapy-dG caused targeted mutations, predominantly G → T transversions, with overall frequencies of ∼11-12%. These frequencies were ∼2-fold higher than that induced by 8-oxo-dG adduct. Replication in E. coli was essentially error-free. To elucidate the mechanisms of bypass of NM-Fapy-dG, we performed replication assays in vitro with a high-fidelity DNA polymerase, Saccharomyces cerevisiae polymerase (pol) δ. It was found that pol δ could catalyze high-fidelity synthesis past NM-Fapy-dG, but only on a template subpopulation, presumably containing the β-anomeric adduct. Consistent with the low mutagenic potential of the β-anomer in vitro, the mutation frequency was significantly reduced when conditions for vector preparation were modified to favor this configuration. Collectively, these data implicate the α-anomer as a major contributor to NM-Fapy-dG-induced mutagenesis in primate cells.
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Affiliation(s)
- Irina G Minko
- From the Oregon Institute of Occupational Health Sciences and
| | - Carmelo J Rizzo
- the Departments of Chemistry and Biochemistry, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | - R Stephen Lloyd
- From the Oregon Institute of Occupational Health Sciences and .,the Departments of Molecular and Medical Genetics and Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon 97239 and
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10
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Peterson LA. Context Matters: Contribution of Specific DNA Adducts to the Genotoxic Properties of the Tobacco-Specific Nitrosamine NNK. Chem Res Toxicol 2017; 30:420-433. [PMID: 28092943 PMCID: PMC5473167 DOI: 10.1021/acs.chemrestox.6b00386] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent pulmonary carcinogen in laboratory animals. It is classified as a Group 1 human carcinogen by the International Agency for Cancer Research. NNK is bioactivated upon cytochrome P450 catalyzed hydroxylation of the carbon atoms adjacent to the nitrosamino group to both methylating and pyridyloxobutylating agents. Both pathways generate a spectrum of DNA damage that contributes to the overall mutagenic and toxic properties of this compound. NNK is also reduced to form 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), which is also carcinogenic. Like NNK, NNAL requires metabolic activation to DNA alkylating agents. Methyl hydroxylation of NNAL generates pyridylhydroxybutyl DNA adducts, and methylene hydroxylation leads to DNA methyl adducts. The consequence of this complex metabolism is that NNK generates a vast spectrum of DNA damage, any form of which can contribute to the overall carcinogenic properties of this potent pulmonary carcinogen. This Perspective reviews the chemistry and genotoxic properties of the collection of DNA adducts formed from NNK. In addition, it provides evidence that multiple adducts contribute to the overall carcinogenic properties of this chemical. The adduct that contributes to the genotoxic effects of NNK depends on the context, such as the relative amounts of each DNA alkylating pathway occurring in the model system, the levels and genetic variants of key repair enzymes, and the gene targeted for mutation.
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Affiliation(s)
- Lisa A Peterson
- Masonic Cancer Center and Division of Environmental Health Sciences, University of Minnesota , Minneapolis, Minnesota 55455, United States
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11
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Abstract
The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent pulmonary carcinogen in laboratory animals. It is classified as a Group 1 human carcinogen by the International Agency for Cancer Research. NNK is bioactivated upon cytochrome P450 catalyzed hydroxylation of the carbon atoms adjacent to the nitrosamino group to both methylating and pyridyloxobutylating agents. Both pathways generate a spectrum of DNA damage that contributes to the overall mutagenic and toxic properties of this compound. NNK is also reduced to form 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), which is also carcinogenic. Like NNK, NNAL requires metabolic activation to DNA alkylating agents. Methyl hydroxylation of NNAL generates pyridylhydroxybutyl DNA adducts, and methylene hydroxylation leads to DNA methyl adducts. The consequence of this complex metabolism is that NNK generates a vast spectrum of DNA damage, any form of which can contribute to the overall carcinogenic properties of this potent pulmonary carcinogen. This Perspective reviews the chemistry and genotoxic properties of the collection of DNA adducts formed from NNK. In addition, it provides evidence that multiple adducts contribute to the overall carcinogenic properties of this chemical. The adduct that contributes to the genotoxic effects of NNK depends on the context, such as the relative amounts of each DNA alkylating pathway occurring in the model system, the levels and genetic variants of key repair enzymes, and the gene targeted for mutation.
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Affiliation(s)
- Lisa A Peterson
- Masonic Cancer Center and Division of Environmental Health Sciences, University of Minnesota , Minneapolis, Minnesota 55455, United States
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12
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Abstract
DNA nucleobases are the prime targets for chemical modifications by endogenous and exogenous electrophiles. Alkylation of the N7 position of guanine and adenine in DNA triggers base-catalyzed imidazole ring opening and the formation of N5-substituted formamidopyrimidine (N5-R-FAPy) lesions. Me-FAPy-dG adducts induced by exposure to methylating agents and AFB-FAPy-dG lesions formed by aflatoxin B1 have been shown to persist in cells and to contribute to toxicity and mutagenicity. In contrast, the biological outcomes of other N5-substituted FAPy lesions have not been fully elucidated. To enable their structural and biological evaluation, N5-R-FAPy adducts must be site-specifically incorporated into synthetic DNA strands using phosphoramidite building blocks, which can be complicated by their unusual structural complexity. N5-R-FAPy exist as a mixture of rotamers and can undergo isomerization between α, β anomers and furanose-pyranose forms. In this Perspective, we will discuss the main types of N5-R-FAPy adducts and summarize the strategies for their synthesis and structural elucidation. We will also summarize the chemical biology studies conducted with N5-R-FAPy-containing DNA to elucidate their effects on DNA replication and to identify the mechanisms of N5-R-FAPy repair.
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Affiliation(s)
- Suresh S. Pujari
- Department of Medicinal Chemistry and Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Natalia Tretyakova
- Department of Medicinal Chemistry and Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
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13
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Gao X, Huang H. Synthesis of N 7-Alkyl-9-deaza-2'-deoxyguanosines Containing Polar N 7 Chains. Examples of Chemically Stable Analogues of N 7-Hydroxyethyl and N 7-Oxoethyl Adducts of 2'-Deoxyguanosine. J Org Chem 2016; 81:11697-11705. [PMID: 27805399 DOI: 10.1021/acs.joc.6b02110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Development of chemically stable analogues of unstable DNA lesions enables accurate study of polymerase bypass. We report the design and synthesis of N7-hydroxyethyl-9-deaza-2'-deoxyguanosine and N7-oxoethyl-9-deaza-2'-deoxyguanosine as the analogues of N7-hydroxyethyl-2'-deoxyguanosine and N7-oxoethyl-2'-deoxyguanosine, respectively. We also developed the synthesis of these two nucleosides whose N7 side chains are protected by TBS for the convenience of conversion to phosphoramidites.
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Affiliation(s)
- Xun Gao
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology , Newark, New Jersey 07102, United States
| | - Haidong Huang
- 4Catalyzer, 530 Old Whitfield Street, Guilford, Connecticut 06437, United States
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14
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Basu AK, Pande P, Bose A. Translesion Synthesis of 2'-Deoxyguanosine Lesions by Eukaryotic DNA Polymerases. Chem Res Toxicol 2016; 30:61-72. [PMID: 27760288 PMCID: PMC5241707 DOI: 10.1021/acs.chemrestox.6b00285] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
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With the discovery
of translesion synthesis DNA polymerases, great
strides have been made in the last two decades in understanding the
mode of replication of various DNA lesions in prokaryotes and eukaryotes.
A database search indicated that approximately 2000 articles on this
topic have been published in this period. This includes research involving
genetic and structural studies as well as in vitro experiments using purified DNA polymerases and accessory proteins.
It is a daunting task to comprehend this exciting and rapidly emerging
area of research. Even so, as the majority of DNA damage occurs at
2′-deoxyguanosine residues, this perspective attempts to summarize
a subset of this field, focusing on the most relevant eukaryotic DNA
polymerases responsible for their bypass.
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Affiliation(s)
- Ashis K Basu
- Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269, United States
| | - Paritosh Pande
- Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269, United States
| | - Arindam Bose
- Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269, United States
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15
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Patra A, Banerjee S, Johnson Salyard TL, Malik CK, Christov PP, Rizzo CJ, Stone MP, Egli M. Structural Basis for Error-Free Bypass of the 5-N-Methylformamidopyrimidine-dG Lesion by Human DNA Polymerase η and Sulfolobus solfataricus P2 Polymerase IV. J Am Chem Soc 2015; 137:7011-4. [PMID: 25988947 DOI: 10.1021/jacs.5b02701] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
N(6)-(2-Deoxy-D-erythro-pentofuranosyl)-2,6-diamino-3,4-dihydro-4-oxo-5-N-methylformamidopyrimidine (MeFapy-dG) arises from N7-methylation of deoxyguanosine followed by imidazole ring opening. The lesion has been reported to persist in animal tissues. Previous in vitro replication bypass investigations of the MeFapy-dG adduct revealed predominant insertion of C opposite the lesion, dependent on the identity of the DNA polymerase (Pol) and the local sequence context. Here we report crystal structures of ternary Pol·DNA·dNTP complexes between MeFapy-dG-adducted DNA template:primer duplexes and the Y-family polymerases human Pol η and P2 Pol IV (Dpo4) from Sulfolobus solfataricus. The structures of the hPol η and Dpo4 complexes at the insertion and extension stages, respectively, are representative of error-free replication, with MeFapy-dG in the anti conformation and forming Watson-Crick pairs with dCTP or dC.
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Affiliation(s)
- Amritraj Patra
- †Department of Biochemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt Institute of Chemical Biology, Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Surajit Banerjee
- ‡Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt Institute of Chemical Biology, Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37235, United States.,§Northeastern Collaborative Access Team and Department of Chemistry and Chemical Biology, Cornell University, Argonne National Laboratory, Building 436E, Argonne, Illinois 60439, United States
| | - Tracy L Johnson Salyard
- ‡Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt Institute of Chemical Biology, Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Chanchal K Malik
- ‡Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt Institute of Chemical Biology, Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Plamen P Christov
- ‡Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt Institute of Chemical Biology, Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Carmelo J Rizzo
- ‡Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt Institute of Chemical Biology, Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Michael P Stone
- ‡Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt Institute of Chemical Biology, Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Martin Egli
- †Department of Biochemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt Institute of Chemical Biology, Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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16
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Earley LF, Minko IG, Christov PP, Rizzo CJ, Lloyd RS. Mutagenic spectra arising from replication bypass of the 2,6-diamino-4-hydroxy-N(5)-methyl formamidopyrimidine adduct in primate cells. Chem Res Toxicol 2013; 26:1108-14. [PMID: 23763662 DOI: 10.1021/tx4001495] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
DNA exposures to electrophilic methylating agents that are commonly used during chemotherapeutic treatments cause diverse chemical modifications of nucleobases, with reaction at N7-dG being the most abundant. Although this base modification frequently results in destabilization of the glycosyl bond and spontaneous depurination, the adduct can react with hydroxide ion to yield a stable, ring-opened MeFapy-dG, and this lesion has been reported to persist in animal tissues. Results from prior in vitro replication bypass investigations of the MeFapy-dG adduct had revealed complex spectra of replication errors that differed depending on the identity of DNA polymerase and the local sequence context. In this study, a series of nine site-specifically modified MeFapy-dG-containing oligodeoxynucleotides were engineered into a shuttle vector and subjected to replication in primate cells. In all nine sequence contexts examined, MeFapy-dG was shown to be associated with a strong mutator phenotype, predominantly causing base substitutions, with G to T transversions being most common. Single and dinucleotide deletions were also found in a subset of the sequence contexts. Interestingly, single-nucleotide deletions occurred at not only the adducted site, but also one nucleotide downstream of the adduct. Standard models for primer-template misalignment could account for some but not all mutations observed. These data demonstrate that in addition to mutagenesis predicted from replication of DNAs containing O(6)-Me-dG and O(4)-Me-dT, the MeFapy-dG adduct likely contributes to mutagenic events following chemotherapeutic treatments.
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Affiliation(s)
- Lauriel F Earley
- Center for Research on Occupational and Environmental Toxicology and §Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon 97239, United States
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