1
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Zhao Z, Bai J, Liu C, Wang Y, Wang S, Zhao F, Gu Q. Metabolomics analysis of amino acid and fatty acids in colorectal cancer patients based on tandem mass spectrometry. J Clin Biochem Nutr 2023; 73:161-171. [PMID: 37700848 PMCID: PMC10493213 DOI: 10.3164/jcbn.22-110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 03/18/2023] [Indexed: 09/14/2023] Open
Abstract
Metabolic differences between colorectal cancer (CRC) and NI (NI) play an important role in early diagnoses and in-time treatments. We investigated the metabolic alterations between CRC patients and NI, and identified some potential biomarkers, and these biomarkers might be used as indicators for diagnosis of CRC. In this study, there were 79 NI, 50 CRC I patients, 52 CRC II patients, 56 CRC III patients, and 52 CRC IV patients. MS-MS was used to measure the metabolic alterations. Univariate and multivariate data analysis and metabolic pathway analysis were applied to analyze metabolic data and determine differential metabolites. These indicators revealed that amino acid and fatty acids could separate these groups. Several metabolites indicated an excellent variables capability in the separation of CRC patients and NI. Ornithine, arginine, octadecanoyl carnitine, palmitoyl carnitine, adipoyl carnitine, and butyryl carnitine/propanoyl carnitine were selected to distinguish the CRC patients and NI. And methionine and propanoyl carnitine, were directly linked to different stages of CRC. Receiver operating characteristics curves and variables importance in projection both represented an excellent performance of these metabolites. In conclusion, we assessed the difference between CRC patients and NI, which supports guidelines for an early diagnosis and effective treatment.
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Affiliation(s)
- Zhuo Zhao
- Intensive Care Unit, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, 121001, China
| | - Jing Bai
- School of Pharmaceutical Sciences, Liaoning University, Shenyang, 110036, China
| | - Chang Liu
- College of Chemistry, Liaoning University, Shenyang, 110036, China
| | - Yansong Wang
- Intensive Care Unit, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, 121001, China
| | | | | | - Qiufang Gu
- School of Nursing, Jinzhou Medical University, Jinzhou, 121001, China
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2
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Yin J, Gates KS, Wang Y. N-Methyl- N-nitrosourea Induced 3'-Glutathionylated DNA-Cleavage Products in Mammalian Cells. Anal Chem 2022; 94:15595-15603. [PMID: 36332130 PMCID: PMC9869666 DOI: 10.1021/acs.analchem.2c02003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Apurinic/apyrimidinic (AP) sites, that is, abasic sites, are among the most frequently induced DNA lesions. Spontaneous or DNA glycosylase-mediated β-elimination of the 3'-phosphoryl group can lead to strand cleavages at AP sites to yield a highly reactive, electrophilic 3'-phospho-α,β-unsaturated aldehyde (3'-PUA) remnant. The latter can react with amine or thiol groups of biological small molecules, DNA, and proteins to yield various damaged 3'-end products. Considering its high intracellular concentration, glutathione (GSH) may conjugate with 3'-PUA to yield 3-glutathionyl-2,3-dideoxyribose (GS-ddR), which may constitute a significant, yet previously unrecognized endogenous lesion. Here, we developed a liquid chromatography tandem mass spectroscopy method, in combination with the use of a stable isotope-labeled internal standard, to quantify GS-ddR in genomic DNA of cultured human cells. Our results revealed the presence of GS-ddR in the DNA of untreated cells, and its level was augmented in cells upon exposure to an alkylating agent, N-methyl-N-nitrosourea (MNU). In addition, inhibition of AP endonuclease (APE1) led to an elevated level of GS-ddR in the DNA of MNU-treated cells. Together, we reported here, for the first time, the presence of appreciable levels of GS-ddR in cellular DNA, the induction of GS-ddR by a DNA alkylating agent, and the role of APE1 in modulating its level in human cells.
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Affiliation(s)
- Jiekai Yin
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403, United States
| | - Kent S Gates
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Yinsheng Wang
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403, United States
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
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3
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Konorev D, Yao L, Turesky RJ. Multi-DNA Adduct and Abasic Site Quantitation In Vivo by Nano-Liquid Chromatography/High-Resolution Orbitrap Tandem Mass Spectrometry: Methodology for Biomonitoring Colorectal DNA Damage. Chem Res Toxicol 2022; 35:1519-1532. [PMID: 36066083 PMCID: PMC9665354 DOI: 10.1021/acs.chemrestox.2c00177] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Epidemiological and mechanistic studies suggest that processed and red meat consumption and tobacco smoking are associated with colorectal cancer (CRC) risk. Several classes of carcinogens, including N-nitroso compounds (NOCs) in processed meats and heterocyclic aromatic amines (HAAs) and polycyclic aromatic hydrocarbons (PAHs) in grilled meats and tobacco smoke, undergo metabolism to reactive intermediates that may form mutation-inducing DNA adducts in the colorectum. Heme iron in red meat may contribute to oxidative DNA damage and endogenous NOC formation. However, the chemicals involved in colorectal DNA damage and the paradigms of CRC etiology remain unproven. There is a critical need to establish physicochemical methods for identifying and quantitating DNA damage induced by genotoxicants in the human colorectum. We established robust nano-liquid chromatography/high-resolution accurate mass Orbitrap tandem mass spectrometry (LC/HRAMS2) methods to measure DNA adducts of nine meat and tobacco-associated carcinogens and lipid peroxidation products in the liver, colon, and rectum of carcinogen-treated rats employing fresh-frozen and formalin-fixed paraffin-embedded (FFPE) tissues. Some NOCs form O6-carboxymethyl-2'-deoxyguanosine, O6-methyl-2'-deoxyguanosine, and unstable quaternary N-linked purine/pyrimidine adducts, which generate apurinic/apyrimidinic (AP) sites. AP sites were quantitated following derivatization with O-(pyridin-3-yl-methyl)hydroxylamine. DNA adduct quantitation was conducted with stable isotope-labeled internal standards, and method performance was validated for accuracy and reproducibility. Limits of quantitation ranged from 0.1 to 1.1 adducts per 108 bases using 3 μg of DNA. Adduct formation in animals ranged from ∼1 in 108 to ∼1 in 105 bases, occurring at comparable levels in fresh-frozen and FFPE specimens for most adducts. AP sites increased by 25- to 75-fold in the colorectum and liver, respectively. Endogenous lipid peroxide-derived 3-(2-deoxy-β-d-erythro-pentofuranosyl)pyrimido[1,2-α]purin-10(3H)-one (M1dG) and 6-oxo-M1dG adduct levels were not increased by carcinogen dosing but increased in FFPE tissues. Human biomonitoring studies can implement LC/HRAMS2 assays for DNA adducts and AP sites outlined in this work to advance our understanding of CRC etiology.
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Affiliation(s)
- Dmitri Konorev
- Masonic Cancer Center, University of Minnesota,
Minneapolis, MN 55455
- Department of Medicinal Chemistry, University of Minnesota,
Minneapolis, MN 55455
| | - Lihua Yao
- Masonic Cancer Center, University of Minnesota,
Minneapolis, MN 55455
- Department of Medicinal Chemistry, University of Minnesota,
Minneapolis, MN 55455
| | - Robert. J. Turesky
- Masonic Cancer Center, University of Minnesota,
Minneapolis, MN 55455
- Department of Medicinal Chemistry, University of Minnesota,
Minneapolis, MN 55455
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4
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Zhang J, Wang Y, Wang Y, Zhang P, Chen HY, Huang S. Discrimination between Different DNA Lesions by Monitoring Single-Molecule Polymerase Stalling Kinetics during Nanopore Sequencing. NANO LETTERS 2022; 22:5561-5569. [PMID: 35713465 DOI: 10.1021/acs.nanolett.2c01833] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
O6-Carboxymethylguanosine (O6-CMG), O6-methylguanosine (O6-MeG), and abasic site (AP site) are DNA lesions induced by alkylating agents. Identification of these lesions in DNA may aid in understanding their relevance to carcinogenesis and may be used for diagnosis. Nanopore sequencing (NPS) may directly report nucleotide modifications solely from the nanopore readout. However, the conventional NPS strategy still suffers from interferences from neighboring sequences. Instead, by observation of the enzymatic stalling kinetics caused by the O6-CMG, O6-MeG, or AP site, discrimination between different DNA lesions is directly achieved. This strategy is not interfered with by the sequence context around the lesion. The lesion, which retards the movement of the DNA through the pore, efficiently prohibits misreading of the DNA lesion. These results suggest a new strategy in the identification of DNA lesions or DNA modifications. It also provides a high-resolution biophysical tool to investigate enzymatic kinetics caused by DNA lesions and the corresponding enzymes.
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Affiliation(s)
- Jinyue Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023 Nanjing, China
| | - Yu Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023 Nanjing, China
| | - Yuqin Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023 Nanjing, China
| | - Panke Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Shuo Huang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023 Nanjing, China
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5
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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: 61] [Impact Index Per Article: 30.5] [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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6
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Aloisi CMN, Escher NA, Kim HS, Geisen SM, Fontana GA, Yeo JE, Schärer OD, Sturla SJ. A combination of direct reversion and nucleotide excision repair counters the mutagenic effects of DNA carboxymethylation. DNA Repair (Amst) 2022; 110:103262. [PMID: 35030424 PMCID: PMC9232693 DOI: 10.1016/j.dnarep.2021.103262] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 02/03/2023]
Abstract
Distinct cellular DNA damage repair pathways maintain the structural integrity of DNA and protect it from the mutagenic effects of genotoxic exposures and processes. The occurrence of O6-carboxymethylguanine (O6-CMG) has been linked to meat consumption and hypothesized to contribute to the development of colorectal cancer. However, the cellular fate of O6-CMG is poorly characterized and there is contradictory data in the literature as to how repair pathways may protect cells from O6-CMG mutagenicity. To better address how cells detect and remove O6-CMG, we evaluated the role of two DNA repair pathways in counteracting the accumulation and toxic effects of O6-CMG. We found that cells deficient in either the direct repair protein O6-methylguanine-DNA methyltransferase (MGMT), or key components of the nucleotide excision repair (NER) pathway, accumulate higher levels O6-CMG DNA adducts than wild type cells. Furthermore, repair-deficient cells were more sensitive to carboxymethylating agents and displayed an increased mutation rate. These findings suggest that a combination of direct repair and NER circumvent the effects O6-CMG DNA damage.
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Affiliation(s)
- Claudia M N Aloisi
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Nora A Escher
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Hyun Suk Kim
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Susanne M Geisen
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Gabriele A Fontana
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Jung-Eun Yeo
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea; Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Orlando D Schärer
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea; Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland.
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7
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Li K, Li Z, Wu J, Gong Y, Guo L, Xie J. In Vitro Evaluation of DNA Damage Effect Markers toward Five Nitrogen Mustards Based on Liquid Chromatography-Tandem Mass Spectrometry. Chem Res Toxicol 2021; 35:99-110. [PMID: 34969250 DOI: 10.1021/acs.chemrestox.1c00346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Endogenous DNA lesions frequently occur due to internal effects such as oxidative stress, inflammation, endogenous alkylation, and epigenetic modifications. However, exposure to chemical toxicants from the environment, diet, or drugs can also induce significant endogenous DNA damage. The quantification of endogenous DNA damage effect markers might reflect the actual DNA damage level of chemical toxicants. Herein, we report a liquid chromatography-triple quadrupole tandem mass spectrometry (LC-QqQ MS/MS) method for simultaneous determination of eight representative endogenous DNA damage biomarkers, including five endogenous DNA damage effect markers (oxidative damage, 8-oxo-dG; lipid peroxidation, εdA and N2-Et-dG; inflammation, 5-Cl-dC; and endogenous alkylation, O6-Me-dG), and three epigenetic modifications (5-m-dC, 5-hm-dC, and N6-Me-dA). The method validation was performed, and the linear range was 0.05 pg to 2 ng (on-column), the limit of detection was 0.02 pg (on-column), and the precision, accuracy, matrix effect, and recovery were all between 85 and 115%. We then applied this method to evaluate endogenous DNA damage to human embryonic lung fibroblast cells exposed to five nitrogen mustards [NMs, i.e., HN1, HN2, HN3, chlorambucil (CB), and cyclophosphamide (CTX)], where curcumin exposure was used as a control due to its inability to induce the formation of endogenous DNA adducts. The amounts of eight DNA adducts in the low-, middle-, and high-concentration exposure groups of five NMs were almost all significantly different from those in the blank group (P < 0.05). We obtained a positive correlation between the contents of eight DNA damage biomarkers and the inhibition dose of five NMs, except for N2-Et-dG and 5-Cl-dC. Via further principal component analysis and partial least squares discriminant analysis, we clustered all NMs into three units with different cytotoxicity levels, that is, HN2 and HN1 (highly toxic), HN3 and CB (moderately toxic), and CTX (less toxic). Moreover, for the same concentration of HN1/2/3 exposure groups, as the cytotoxicity increased according to the order of HN3 < HN1 < HN2, the contents of 8-oxo-dG, 5-m-dC, 5-hm-dC, and N6-Me-dA increased, whereas the content of O6-Me-dG decreased. Therefore, the contents of these DNA damage effect markers were somewhat related to the cytotoxicity and concentration of NMs. We hope that this method will provide an alternative evaluation approach for the toxicological effects of NMs and the safety of the medication.
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Affiliation(s)
- Kexin Li
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
| | - Zehua Li
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
| | - Jianfeng Wu
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
| | - Ying Gong
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
| | - Lei Guo
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
| | - Jianwei Xie
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
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8
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Kostka T, Empl MT, Seiwert N, Geisen SM, Hoffmann P, Adam J, Seeger B, Shay JW, Christmann M, Sturla SJ, Fahrer J, Steinberg P. Repair of O6-carboxymethylguanine adducts by O6-methylguanine-DNA methyltransferase in human colon epithelial cells. Carcinogenesis 2021; 42:1110-1118. [PMID: 34115837 DOI: 10.1093/carcin/bgab049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/23/2021] [Accepted: 06/09/2021] [Indexed: 11/13/2022] Open
Abstract
The protein O6-methylguanine-DNA methyltransferase (MGMT) is able to repair the mutagenic O6-methylguanine adduct back to guanine. In this context, it may protect against colorectal cancer (CRC) formation associated with N-nitroso compounds. Such compounds may be endogenously formed by nitrosylation of amino acids, which can give rise to mutagenic O6-methylguanine (O6-MeG) and O6-carboxymethylguanine (O6-CMG) adducts. It is well-established that O6-MeG is repaired by MGMT. However, up to now, whether O6-CMG is repaired by this enzyme remains unresolved. Therefore, the aim of the present study was to analyze the fate of both types of O6-guanine adducts in the presence and absence of MGMT activity. To this end, MGMT activity was efficiently blocked by its chemical inhibitor O6-benzylguanine in human colon epithelial cells (HCEC). Exposure of cells to azaserine (AZA) caused significantly higher levels of both O6-MeG and O6-CMG adducts in MGMT-inhibited cells, with O6-CMG as the more abundant DNA lesion. Interestingly, MGMT inhibition did not result in higher levels of AZA-induced DNA strand breaks in spite of elevated DNA adduct levels. In contrast, MGMT inhibition significantly increased DNA strand break formation after exposure to temozolomide (TMZ), a drug that exclusively generates O6-MeG adducts. In line with this finding, the viability of the cells was moderately reduced by TMZ upon MGMT inhibition, whereas no clear effect was observed in cells treated with AZA. In conclusion, our study clearly shows that O6-CMG is repaired by MGMT in HCEC, thereby suggesting that MGMT might play an important role as a tumor suppressor in diet-mediated CRC.
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Affiliation(s)
- Tina Kostka
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany.,Institute of Food Science and Human Nutrition, Gottfried Wilhelm Leibniz University Hannover, 30167 Hannover, Germany
| | - Michael T Empl
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany
| | - Nina Seiwert
- Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Susanne M Geisen
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Pascal Hoffmann
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany
| | - Janine Adam
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany
| | - Bettina Seeger
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany.,Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Markus Christmann
- Department of Toxicology, University Medical Center Mainz, 55131 Mainz, Germany
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Jörg Fahrer
- Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Pablo Steinberg
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany.,Max Rubner-Institut, Federal Research Institute of Nutrition and Food, 76131 Karlsruhe, Germany
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9
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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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10
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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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11
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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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12
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Wu J, Wang P, Wang Y. Cytotoxic and mutagenic properties of alkyl phosphotriester lesions in Escherichia coli cells. Nucleic Acids Res 2019. [PMID: 29514270 PMCID: PMC5934668 DOI: 10.1093/nar/gky140] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Exposure to many endogenous and exogenous agents can give rise to DNA alkylation, which constitutes a major type of DNA damage. Among the DNA alkylation products, alkyl phosphotriesters have relatively high frequencies of occurrence and are resistant to repair in mammalian tissues. However, little is known about how these lesions affect the efficiency and fidelity of DNA replication in cells or how the replicative bypass of these lesions is modulated by translesion synthesis DNA polymerases. In this study, we synthesized oligodeoxyribonucleotides containing four pairs (Sp and Rp) of alkyl phosphotriester lesions at a defined site, and examined how these lesions are recognized by DNA replication machinery in Escherichia coli cells. We found that the Sp diastereomer of the alkyl phosphotriester lesions could be efficiently bypassed, whereas the Rp counterparts moderately blocked DNA replication. Moreover, the Sp-methyl phosphotriester induced TT→GT and TT→GC mutations at the flanking TT dinucleotide site, and the induction of these mutations required Ada protein, which is known to remove efficiently the methyl group from the Sp-methyl phosphotriester. Together, our study provided a comprehensive understanding about the recognition of alkyl phosphotriester lesions by DNA replication machinery in cells, and revealed for the first time the Ada-dependent induction of mutations at the Sp-methyl phosphotriester site.
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Affiliation(s)
- Jiabin Wu
- Environmental Toxicology Graduate Program and Department of Chemistry, University of California Riverside, Riverside, CA 92521-0403, USA
| | - Pengcheng Wang
- Environmental Toxicology Graduate Program and Department of Chemistry, University of California Riverside, Riverside, CA 92521-0403, USA
| | - Yinsheng Wang
- Environmental Toxicology Graduate Program and Department of Chemistry, University of California Riverside, Riverside, CA 92521-0403, USA
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13
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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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14
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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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15
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Wang P, Leng J, Wang Y. DNA replication studies of N-nitroso compound-induced O6-alkyl-2'-deoxyguanosine lesions in Escherichia coli. J Biol Chem 2019; 294:3899-3908. [PMID: 30655287 PMCID: PMC6422096 DOI: 10.1074/jbc.ra118.007358] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 01/16/2019] [Indexed: 12/30/2022] Open
Abstract
N-Nitroso compounds (NOCs) are common DNA-alkylating agents, are abundantly present in food and tobacco, and can also be generated endogenously. Metabolic activation of some NOCs can give rise to carboxymethylation and pyridyloxobutylation/pyridylhydroxybutylation of DNA, which are known to be carcinogenic and can lead to gastrointestinal and lung cancer, respectively. Herein, using the competitive replication and adduct bypass (CRAB) assay, along with MS- and NMR-based approaches, we assessed the cytotoxic and mutagenic properties of three O6-alkyl-2'-deoxyguanosine (O6-alkyl-dG) adducts, i.e. O6-pyridyloxobutyl-dG (O6-POB-dG) and O6-pyridylhydroxybutyl-dG (O6-PHB-dG), derived from tobacco-specific nitrosamines, and O6-carboxymethyl-dG (O6-CM-dG), induced by endogenous N-nitroso compounds. We also investigated two neutral analogs of O6-CM-dG, i.e. O6-aminocarbonylmethyl-dG (O6-ACM-dG) and O6-hydroxyethyl-dG (O6-HOEt-dG). We found that, in Escherichia coli cells, these lesions mildly (O6-POB-dG), moderately (O6-PHB-dG), or strongly (O6-CM-dG, O6-ACM-dG, and O6-HOEt-dG) impede DNA replication. The strong blockage effects of the last three lesions were attributable to the presence of hydrogen-bonding donor(s) located on the alkyl functionality of these lesions. Except for O6-POB-dG, which also induced a low frequency of G → T transversions, all other lesions exclusively stimulated G → A transitions. SOS-induced DNA polymerases played redundant roles in bypassing all the O6-alkyl-dG lesions investigated. DNA polymerase IV (Pol IV) and Pol V, however, were uniquely required for inducing the G → A transition for O6-CM-dG exposure. Together, our study expands our knowledge about the recognition of important NOC-derived O6-alkyl-dG lesions by the E. coli DNA replication machinery.
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Affiliation(s)
- Pengcheng Wang
- From the Department of Chemistry, University of California, Riverside, California 92521-0403 and
- the Institute of Surface Analysis and Chemical Biology, University of Jinan, Jinan, Shandong 250022, China
| | - Jiapeng Leng
- From the Department of Chemistry, University of California, Riverside, California 92521-0403 and
| | - Yinsheng Wang
- From the Department of Chemistry, University of California, Riverside, California 92521-0403 and
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16
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Guo S, Leng J, Tan Y, Price NE, Wang Y. Quantification of DNA Lesions Induced by 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol in Mammalian Cells. Chem Res Toxicol 2019; 32:708-717. [PMID: 30714728 DOI: 10.1021/acs.chemrestox.8b00374] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Quantitative measurement of DNA adducts in carcinogen-exposed cells provides the information about the frequency of formation and the rate of removal of DNA lesions in vivo, which yields insights into the initial events of mutagenesis. Metabolic activation of tobacco-specific nitrosamines, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its reduction product 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), leads to pyridyloxobutylation and pyridylhydroxybutylation of DNA. In this study, we employed a highly robust nanoflow liquid chromatography-nanoelectrospray ionization-tandem mass spectrometry (nLC-nESI-MS/MS) coupled with the isotope-dilution method for simultaneous quantification of O6-[4-(3-pyridyl)-4-hydroxylbut-1-yl]-2'-deoxyguanosine ( O6-PHBdG) and O2- and O4-[4-(3-pyridyl)-4-hydroxylbut-1-yl]-thymidine ( O2-PHBdT and O4-PHBdT). Cultured mammalian cells were exposed to a model pyridylhydroxybutylating agent, 4-(acetoxymethylnitrosamino)-1-(3-pyridyl)-1-butanol (NNALOAc), followed by DNA extraction, enzymatic digestion, and sample enrichment prior to nLC-nESI-MS/MS quantification. Our results demonstrate, for the first time, that O4-PHBdT is quantifiable in cellular DNA and naked DNA upon NNALOAc exposure. We also show that nucleotide excision repair (NER) machinery may counteract the formation of O2-PHBdT and O4-PHBdT, and O6-alkylguanine DNA alkyltransferase (AGT) may be responsible for the repair of O6-PHBdG and O4-PHBdT in mammalian cells. Together, our study provides new knowledge about the occurrence and repair of NNAL-induced DNA lesions in mammalian cells.
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17
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Affiliation(s)
- Yang Yu
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403, United States
| | - Pengcheng Wang
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403, United States
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Yuxiang Cui
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403, United States
| | - Yinsheng Wang
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403, United States
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
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18
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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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19
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Leng J, Wang Y. Liquid Chromatography-Tandem Mass Spectrometry for the Quantification of Tobacco-Specific Nitrosamine-Induced DNA Adducts in Mammalian Cells. Anal Chem 2017; 89:9124-9130. [PMID: 28749651 PMCID: PMC5620023 DOI: 10.1021/acs.analchem.7b01857] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Quantification of DNA lesions constitutes one of the main tasks in toxicology and in assessing health risks accompanied by exposure to carcinogens. Tobacco-specific nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) can undergo metabolic transformation to give a reactive intermediate that pyridyloxobutylates nucleobases and phosphate backbone of DNA. Here, we reported a highly sensitive method, relying on the use of nanoflow liquid chromatography-nanoelectrospray ionization-tandem mass spectrometry (nLC-nESI-MS/MS), for the simultaneous quantifications of O6-[4-(3-pyridyl)-4-oxobut-1-yl]-2'-deoxyguanosine (O6-POBdG) as well as O2- and O4-[4-(3-pyridyl)-4-oxobut-1-yl]-thymidine (O2-POBdT and O4-POBdT). By using this method, we measured the levels of the three DNA adducts with the use of 10 μg of DNA isolated from cultured mammalian cells exposed to a model pyridyloxobutylating agent, 4-(acetoxymethylnitrosamino)-1-(3-pyridyl)-1-butanone (NNKOAc). Our results demonstrated, for the first time, the formation of O4-POBdT in naked DNA and in genomic DNA of cultured mammalian cells exposed with NNKOAc. We also revealed that the levels of the three lesions increased with the dose of NNKOAc and that O2-POBdT and O4-POBdT could be subjected to repair by the nucleotide excision repair (NER) pathway. The method reported here will be useful for investigations about the involvement of other DNA repair pathways in the removal of these lesions and for human toxicological studies in the future.
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Affiliation(s)
- Jiapeng Leng
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Yinsheng Wang
- Corresponding Author. Tel.: (951) 827-2700. Fax: (951) 827-4713.
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20
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Räz MH, Dexter HR, Millington CL, van Loon B, Williams DM, Sturla SJ. Bypass of Mutagenic O(6)-Carboxymethylguanine DNA Adducts by Human Y- and B-Family Polymerases. Chem Res Toxicol 2016; 29:1493-503. [PMID: 27404553 DOI: 10.1021/acs.chemrestox.6b00168] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The generation of chemical alkylating agents from nitrosation of glycine and bile acid conjugates in the gastrointestinal tract is hypothesized to initiate carcinogenesis. O(6)-carboxymethylguanine (O(6)-CMG) is a product of DNA alkylation derived from nitrosated glycine. Although the tendency of the structurally related adduct O(6)-methylguanine to code for the misincoporation of TTP during DNA replication is well-established, the impact of the presence of the O(6)-CMG adduct in a DNA template on the efficiency and fidelity of translesion DNA synthesis (TLS) by human DNA polymerases (Pols) has hitherto not been described. Herein, we characterize the ability of the four human TLS Pols η, ι, κ, and ζ and the replicative Pol δ to bypass O(6)-CMG in a prevalent mutational hot-spot for colon cancer. The results indicate that Pol η replicates past O(6)-CMG, incorporating dCMP or dAMP, whereas Pol κ incorporates dCMP only, and Pol ι incorporates primarily dTMP. Additionally, the subsequent extension step was carried out with high efficiency by TLS Pols η, κ, and ζ, while Pol ι was unable to extend from a terminal mismatch. These results provide a first basis of O(6)-CMG-promoted base misincorporation by Y- and B-family polymerases potentially leading to mutational signatures associated with colon cancer.
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Affiliation(s)
- Michael H Räz
- Department of Health Sciences and Technology, ETH Zürich , Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Hannah R Dexter
- Center for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield , Sheffield S3 7HF, United Kingdom
| | - Christopher L Millington
- Center for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield , Sheffield S3 7HF, United Kingdom
| | - Barbara van Loon
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU) , Erling Skjalgssons gate 1, 7491 Trondheim, Norway
| | - David M Williams
- Center for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield , Sheffield S3 7HF, United Kingdom
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zürich , Schmelzbergstrasse 9, 8092 Zürich, Switzerland
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