1
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McGlynn KA, Petrick JL, Groopman JD. Liver Cancer: Progress and Priorities. Cancer Epidemiol Biomarkers Prev 2024; 33:1261-1272. [PMID: 39354815 DOI: 10.1158/1055-9965.epi-24-0686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 07/17/2024] [Accepted: 08/05/2024] [Indexed: 10/03/2024] Open
Abstract
Liver cancer, the sixth most frequently occurring cancer in the world and the third most common cause of cancer mortality, has wide geographical variation in both incidence and mortality rates. At the end of the 20th century, incidence rates began declining in some high-rate areas and increasing in some lower-rate areas. These trends were undoubtedly driven by the shifting contributions of both well-established and more novel risk factors. While notable strides have been made in combating some major risk factors, such as hepatitis B virus and hepatitis C virus, the emergence of metabolic conditions as important drivers of liver cancer risk indicates that much work remains to be done in prevention. As liver cancer is strongly associated with economic and social deprivation, research, early-diagnosis, and treatment among disadvantaged populations are of paramount importance.
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Affiliation(s)
- Katherine A McGlynn
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland
| | | | - John D Groopman
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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2
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Bellamri M, Yao L, Tomar R, Vartanian V, Rizzo CJ, Stone MP, Groopman JD, Lloyd RS, Turesky RJ. Mass Spectrometry-Based Method to Measure Aflatoxin B 1 DNA Adducts in Formalin-Fixed Paraffin-Embedded Tissues. Chem Res Toxicol 2024; 37:633-642. [PMID: 38498000 PMCID: PMC11279702 DOI: 10.1021/acs.chemrestox.4c00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Aflatoxin B1 (AFB1) is a potent human liver carcinogen produced by certain molds, particularly Aspergillus flavus and Aspergillus parasiticus, which contaminate peanuts, corn, rice, cottonseed, and ground and tree nuts, principally in warm and humid climates. AFB1 undergoes bioactivation in the liver to produce AFB1-exo-8,9-epoxide, which forms the covalently bound cationic AFB1-N7-guanine (AFB1-N7-Gua) DNA adduct. This adduct is unstable and undergoes base-catalyzed opening of the guanine imidazolium ring to form two ring-opened diastereomeric 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl-formamido)-9-hydroxy-aflatoxin B1 (AFB1-FapyGua) adducts. The AFB1 formamidopyrimidine (Fapy) adducts induce G → T transversion mutations and are likely responsible for the carcinogenic effects of AFB1. Quantitative liquid chromatography-mass spectrometry (LC-MS) methods have shown that AFB1-N7-Gua is eliminated in rodent and human urine, whereas ring-opened AFB1-FapyGua adducts persist in rodent liver. However, fresh frozen biopsy tissues are seldom available for biomonitoring AFB1 DNA adducts in humans, impeding research advances in this potent liver carcinogen. In contrast, formalin-fixed paraffin-embedded (FFPE) specimens used for histopathological analysis are often accessible for molecular studies. However, ensuring nucleic acid quality presents a challenge due to incomplete reversal of formalin-mediated DNA cross-links, which can preclude accurate quantitative measurements of DNA adducts. In this study, employing ion trap or high-resolution accurate Orbitrap mass spectrometry, we demonstrate that ring-opened AFB1-FapyGua adducts formed in AFB1-exposed newborn mice are stable to the formalin fixation and DNA de-cross-linking retrieval processes. The AFB1-FapyGua adducts can be detected at levels comparable to those in a match of fresh frozen liver. Orbitrap MS2 measurements can detect AFB1-FapyGua at a quantification limit of 4.0 adducts per 108 bases when only 0.8 μg of DNA is assayed on the column. Thus, our breakthrough DNA retrieval technology can be adapted to screen for AFB1 DNA adducts in FFPE human liver specimens from cohorts at risk of this potent liver carcinogen.
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Affiliation(s)
- Medjda Bellamri
- 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
| | - Rachana Tomar
- Department of Chemistry, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | - Vladimir Vartanian
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, Oregon 97239
| | - Carmelo J. Rizzo
- Department of Chemistry, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | - Michael P. Stone
- Department of Chemistry, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | - John D. Groopman
- Department of Environmental Health and Engineering, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205
| | - R. Stephen Lloyd
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, Oregon 97239
| | - 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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3
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Minko IG, Kellum AH, Stone MP, Lloyd RS. The aflatoxin B 1-induced imidazole ring-opened guanine adduct: High mutagenic potential that is minimally affected by sequence context. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2024; 65 Suppl 1:9-13. [PMID: 37303259 PMCID: PMC10711146 DOI: 10.1002/em.22556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/25/2023] [Accepted: 06/08/2023] [Indexed: 06/13/2023]
Abstract
Dietary exposure to aflatoxin B1 (AFB1) is a recognized risk factor for developing hepatocellular carcinoma. The mutational signature of AFB1 is characterized by high-frequency base substitutions, predominantly G>T transversions, in a limited subset of trinucleotide sequences. The 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl-formamido)-9-hydroxyaflatoxin B1 (AFB1-FapyGua) has been implicated as the primary DNA lesion responsible for AFB1-induced mutations. This study evaluated the mutagenic potential of AFB1-FapyGua in four sequence contexts, including hot- and cold-spot sequences as apparent in the mutational signature. Vectors containing site-specific AFB1-FapyGua lesions were replicated in primate cells and the products of replication were isolated and sequenced. Consistent with the role of AFB1-FapyGua in AFB1-induced mutagenesis, AFB1-FapyGua was highly mutagenic in all four sequence contexts, causing G>T transversions and other base substitutions at frequencies of ~80%-90%. These data suggest that the unique mutational signature of AFB1 is not explained by sequence-dependent fidelity of replication past AFB1-FapyGua lesions.
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Affiliation(s)
- Irina G. Minko
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239
| | | | | | - R. Stephen Lloyd
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239
- Department of Molecular and Medical Genetics, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239
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4
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Minko I, Luzadder M, Vartanian V, Rice SM, Nguyen M, Sanchez-Contreras M, Van P, Kennedy S, McCullough A, Lloyd R. Frequencies and spectra of aflatoxin B 1-induced mutations in liver genomes of NEIL1-deficient mice as revealed by duplex sequencing. NAR MOLECULAR MEDICINE 2024; 1:ugae006. [PMID: 38779538 PMCID: PMC11105970 DOI: 10.1093/narmme/ugae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 04/18/2024] [Accepted: 05/16/2024] [Indexed: 05/25/2024]
Abstract
Increased risk for the development of hepatocellular carcinoma (HCC) is driven by a number of etiological factors including hepatitis viral infection and dietary exposures to foods contaminated with aflatoxin-producing molds. Intracellular metabolic activation of aflatoxin B1 (AFB1) to a reactive epoxide generates highly mutagenic AFB1-Fapy-dG adducts. Previously, we demonstrated that repair of AFB1-Fapy-dG adducts can be initiated by the DNA glycosylase NEIL1 and that male Neil1-/- mice were significantly more susceptible to AFB1-induced HCC relative to wild-type mice. To investigate the mechanisms underlying this enhanced carcinogenesis, WT and Neil1-/- mice were challenged with a single, 4 mg/kg dose of AFB1 and frequencies and spectra of mutations were analyzed in liver DNAs 2.5 months post-injection using duplex sequencing. The analyses of DNAs from AFB1-challenged mice revealed highly elevated mutation frequencies in the nuclear genomes of both males and females, but not the mitochondrial genomes. In both WT and Neil1-/- mice, mutation spectra were highly similar to the AFB1-specific COSMIC signature SBS24. Relative to wild-type, the NEIL1 deficiency increased AFB1-induced mutagenesis with concomitant elevated HCCs in male Neil1-/- mice. Our data establish a critical role of NEIL1 in limiting AFB1-induced mutagenesis and ultimately carcinogenesis.
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Affiliation(s)
- Irina G Minko
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA
| | - Michael M Luzadder
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA
| | - Vladimir L Vartanian
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA
| | - Sean P M Rice
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA
- School of Public Health, Oregon Health & Science University - Portland State University, Portland, OR, USA
| | - Megan M Nguyen
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | | | - Phu Van
- TwinStrand Biosciences, Inc., Seattle, WA, USA
| | - Scott R Kennedy
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Amanda K McCullough
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | - R Stephen Lloyd
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
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5
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Kobets T, Hickey C, Johnson G, Duan JD, Etter S, Smith B, Williams GM. Assessment of no-observed-effect-levels for DNA adducts formation by genotoxic carcinogens in fetal turkey livers. Toxicology 2024; 501:153714. [PMID: 38141718 DOI: 10.1016/j.tox.2023.153714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/08/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023]
Abstract
For genotoxic carcinogens, covalent binding to DNA is a critical initiating event in tumorigenesis. The present research investigated dose-effect relationships of three genotoxic carcinogens representing different structural classes, 2-acetylaminofluorene (2-AAF), benzo[a]pyrene (B[a]P) and quinoline (QUI), to assess the existence of no-observed-effect-levels (NOELs) for the formation of DNA adducts. Carcinogens were administered into the air sac of fertilized turkey eggs over wide dose ranges in three daily injections on days 22 to 24 of incubation. DNA adducts were measured in the fetal turkey livers by the 32P-nucleotide postlabeling (NPL) assay. B[a]P and QUI produced DNA adducts in a dosage-related manner and exhibited NOELs at 0.65 and 0.35 mg/kg bw/day, respectively. In contrast, 2-AAF formed DNA adducts at all tested dosages down to 0.005 mg/kg bw/day. Benchmark dose (BMD) analysis identified the potencies of 2-AAF and QUI to be similar, while B[a]P was the least potent compound. Overall, findings in fetal turkey livers demonstrated that exposure levels to genotoxic compounds that do not result in DNA adducts can exist but are not evident with all carcinogens of this type. The use of mechanistic dose-effect studies for genotoxic endpoints can provide critical information for prioritization of concerns for risk assessment.
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Affiliation(s)
- Tetyana Kobets
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA.
| | | | | | - Jian-Dong Duan
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
| | | | - Benjamin Smith
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA
| | - Gary M Williams
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
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6
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Zuckerman JT, Minko IG, Kant M, Jaruga P, Stone MP, Dizdaroglu M, McCullough AK, Lloyd RS. Functional analyses of single nucleotide polymorphic variants of the DNA glycosylase NEIL1 in sub-Saharan African populations. DNA Repair (Amst) 2023; 129:103544. [PMID: 37517321 PMCID: PMC10546947 DOI: 10.1016/j.dnarep.2023.103544] [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: 05/17/2023] [Revised: 07/07/2023] [Accepted: 07/18/2023] [Indexed: 08/01/2023]
Abstract
Nei-like glycosylase 1 (NEIL1) is a DNA repair enzyme that initiates the base excision repair (BER) pathway to cleanse the human genome of damage. The substrate specificity of NEIL1 includes several common base modifications formed under oxidative stress conditions, as well as the imidazole ring open adducts that are induced by alkylating agents following initial modification at N7 guanine. An example of the latter is the persistent and mutagenic 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl-formamido)-9-hydroxyaflatoxin B1 (AFB1-FapyGua) adduct, resulting from the alkylating agent aflatoxin B1 (AFB1) exo-8-9-epoxide. Naturally occurring single nucleotide polymorphic (SNP) variants of NEIL1 are hypothesized to be associated with an increased risk for development of early-onset hepatocellular carcinoma (HCC), especially in environments with high exposures to aflatoxins and chronic inflammation from viral infections and alcohol consumption. Given that AFB1 exposures and hepatitis B viral (HBV) infections represent a major problem in the developing countries of sub-Saharan Africa, it is pertinent to study SNP NEIL1 variants that are present in this geographic region. In this investigation, we characterized the three most common NEIL1 variants found in this region: P321A, R323G, and I182M. Biochemical analyses were conducted to determine the proficiencies of these variants in initiating the repair of DNA lesions. Our data show that damage recognition and excision activities of P321A and R323G were near that of wild-type (WT) NEIL1 for both thymine glycol (ThyGly) and AFB1-FapyGua. The substrate specificities of these variants with respect to various oxidatively-induced base lesions were also similar to that of WT. In contrast, the I182M variant was unstable, such that it precipitated under a variety of conditions and underwent rapid inactivation at a biologically relevant temperature, with partial stabilization being observed in the presence of undamaged DNA. This study provides insight regarding the potential increased risk for early-onset HCC in human populations carrying the NEIL1 I182M variant.
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Affiliation(s)
- Jamie T Zuckerman
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, United States
| | - Irina G Minko
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, United States
| | - Melis Kant
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States
| | - Pawel Jaruga
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States
| | - Michael P Stone
- Department of Chemistry, Vanderbilt University, Nashville, TN 37240, United States
| | - Miral Dizdaroglu
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States
| | - Amanda K McCullough
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, United States; Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, United States
| | - R Stephen Lloyd
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, United States; Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, United States.
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7
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Poulsgaard GA, Sørensen SG, Juul RI, Nielsen MM, Pedersen JS. Sequence dependencies and mutation rates of localized mutational processes in cancer. Genome Med 2023; 15:63. [PMID: 37592287 PMCID: PMC10436389 DOI: 10.1186/s13073-023-01217-z] [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: 02/21/2023] [Accepted: 08/02/2023] [Indexed: 08/19/2023] Open
Abstract
BACKGROUND Cancer mutations accumulate through replication errors and DNA damage coupled with incomplete repair. Individual mutational processes often show nucleotide sequence and functional region preferences. As a result, some sequence contexts mutate at much higher rates than others, with additional variation found between functional regions. Mutational hotspots, with recurrent mutations across cancer samples, represent genomic positions with elevated mutation rates, often caused by highly localized mutational processes. METHODS We count the 11-mer genomic sequences across the genome, and using the PCAWG set of 2583 pan-cancer whole genomes, we associate 11-mers with mutational signatures, hotspots of single nucleotide variants, and specific genomic regions. We evaluate the mutation rates of individual and combined sets of 11-mers and derive mutational sequence motifs. RESULTS We show that hotspots generally identify highly mutable sequence contexts. Using these, we show that some mutational signatures are enriched in hotspot sequence contexts, corresponding to well-defined sequence preferences for the underlying localized mutational processes. This includes signature 17b (of unknown etiology) and signatures 62 (POLE deficiency), 7a (UV), and 72 (linked to lymphomas). In some cases, the mutation rate and sequence preference increase further when focusing on certain genomic regions, such as signature 62 in transcribed regions, where the mutation rate is increased up to 9-folds over cancer type and mutational signature average. CONCLUSIONS We summarize our findings in a catalog of localized mutational processes, their sequence preferences, and their estimated mutation rates.
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Affiliation(s)
- Gustav Alexander Poulsgaard
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 82, 8200, Aarhus N, Denmark
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Simon Grund Sørensen
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 82, 8200, Aarhus N, Denmark
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Randi Istrup Juul
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 82, 8200, Aarhus N, Denmark
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Morten Muhlig Nielsen
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 82, 8200, Aarhus N, Denmark
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Jakob Skou Pedersen
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 82, 8200, Aarhus N, Denmark.
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark.
- Bioinformatics Research Centre (BiRC), Aarhus University, University City 81, Building 1872, 3Rd Floor, 8000, Aarhus C, Denmark.
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8
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Wang H, Wang R, Fang J. A spliceosome-associated gene signature aids in predicting prognosis and tumor microenvironment of hepatocellular carcinoma. Aging (Albany NY) 2023; 15:204765. [PMID: 37301543 PMCID: PMC10292887 DOI: 10.18632/aging.204765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 05/17/2023] [Indexed: 06/12/2023]
Abstract
Splicing alterations have been shown to be key tumorigenesis drivers. In this study, we identified a novel spliceosome-related genes (SRGs) signature to predict the overall survival (OS) of patients with hepatocellular carcinoma (HCC). A total of 25 SRGs were identified from the GSE14520 dataset (training set). Univariate and least absolute shrinkage and selection operator (LASSO) regression analyses were utilized to construct the signature using genes with predictive significance. We then constructed a risk model using six SRGs (BUB3, IGF2BP3, RBM3, ILF3, ZC3H13, and CCT3). The reliability and predictive power of the gene signature were validated in two validation sets (TCGA and GSE76427 dataset). Patients in training and validation sets were divided into high and low-risk groups based on the gene signature. Patients in high-risk groups exhibited a poorer OS than in low-risk groups both in the training set and two validation sets. Next, risk score, BCLC staging, TNM staging, and multinodular were combined in a nomogram for OS prediction, and the decision curve analysis (DCA) curve exhibited the excellent prediction performance of the nomogram. The functional enrichment analyses demonstrated high-risk score patients were closely related to multiple oncology characteristics and invasive-related pathways, such as Cell cycle, DNA replication, and Spliceosome. Different compositions of the tumor microenvironment and immunocyte infiltration ratio might contribute to the prognostic difference between high and low-risk score groups. In conclusion, a spliceosome-related six-gene signature exhibited good performance for predicting the OS of patients with HCC, which may aid in clinical decision-making for individual treatment.
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Affiliation(s)
- Huaxiang Wang
- Department of Hepatobiliary and Pancreatic Surgery, Taihe Hospital, Affiliated Hospital of Hubei University of Medicine, Shiyan 442000, Hubei, China
| | - Ruling Wang
- Department of Hepatobiliary and Pancreatic Surgery, Taihe Hospital, Affiliated Hospital of Hubei University of Medicine, Shiyan 442000, Hubei, China
| | - Jian Fang
- Department of Hepatobiliary Medicine, The Third People’s Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou 350108, Fujian, China
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9
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Jaruga P, Tomar R, Kant M, Vartanian V, Sexton B, Rizzo CJ, Turesky RJ, Stone MP, Lloyd RS, Dizdaroglu M. Synthesis and Characterization of 15N 5-Labeled Aflatoxin B 1-Formamidopyrimidines and Aflatoxin B 1-N7-Guanine from a Partial Double-Stranded Oligodeoxynucleotide as Internal Standards for Mass Spectrometric Measurements. ACS OMEGA 2023; 8:14841-14854. [PMID: 37125130 PMCID: PMC10134230 DOI: 10.1021/acsomega.3c01328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 03/20/2023] [Indexed: 05/03/2023]
Abstract
Aflatoxin B1 (AFB1) exposure through contaminated food is a primary contributor to hepatocellular carcinogenesis worldwide. Hepatitis B viral infections in livers dramatically increase the carcinogenic potency of AFB1 exposures. Liver cytochrome P450 oxidizes AFB1 to the epoxide, which in turn reacts with N7-guanine in DNA, producing the cationic trans-8,9-dihydro-8-(N7-guanyl)-9-hydroxyaflatoxin B1 adduct (AFB1-N7-Gua). The opening of the imidazole ring of AFB1-N7-Gua under physiological conditions causes the formation of the cis- and trans-diastereomers of 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl-formamido)-9-hydroxyaflatoxin B1 (AFB1-FapyGua). These adducts primarily lead to G → T mutations, with AFB1-FapyGua being significantly more mutagenic than AFB1-N7-Gua. The unequivocal identification and accurate quantification of these AFB1-Gua adducts as biomarkers are essential for a fundamental understanding and prevention of AFB1-induced hepatocellular carcinogenesis. Among a variety of analytical techniques used for this purpose, liquid chromatography-tandem mass spectrometry, with the use of the stable isotope-labeled analogues of AFB1-FapyGua and AFB1-N7-Gua as internal standards, provides the greatest accuracy and sensitivity. cis-AFB1-FapyGua-15N5, trans-AFB1-FapyGua-15N5, and AFB1-N7-Gua-15N5 have been synthesized and used successfully as internal standards. However, the availability of these standards from either academic institutions or commercial sources ceased to exist. Thus, quantitative genomic data regarding AFB1-induced DNA damage in animal models and humans remain challenging to obtain. Previously, AFB1-N7-Gua-15N5 was prepared by reacting AFB1-exo-8,9-epoxide with the uniformly 15N5-labeled DNA isolated from algae grown in a pure 15N-environment, followed by alkali treatment, resulting in the conversion of AFB1-N7-Gua-15N5 to AFB1-FapyGua-15N5. In the present work, we used a different and simpler approach to synthesize cis-AFB1-FapyGua-15N5, trans-AFB1-FapyGua-15N5, and AFB1-N7-Gua-15N5 from a partial double-stranded 11-mer Gua-15N5-labeled oligodeoxynucleotide, followed by isolation and purification. We also show the validation of these 15N5-labeled standards for the measurement of cis-AFB1-FapyGua, trans-AFB1-FapyGua, and AFB1-N7-Gua in DNA of livers of AFB1-treated mice.
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Affiliation(s)
- Pawel Jaruga
- Biomolecular
Measurement Division, National Institute
of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Rachana Tomar
- Department
of Chemistry, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Melis Kant
- Biomolecular
Measurement Division, National Institute
of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Vladimir Vartanian
- Oregon
Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - Benjamin Sexton
- Department
of Chemistry, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Carmelo J. Rizzo
- Department
of Chemistry, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Robert J. Turesky
- Masonic
Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Michael P. Stone
- Department
of Chemistry, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - R. Stephen Lloyd
- Oregon
Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - Miral Dizdaroglu
- Biomolecular
Measurement Division, National Institute
of Standards and Technology, Gaithersburg, Maryland 20899, United States
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10
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Jiang Y, Mingard C, Huber SM, Takhaveev V, McKeague M, Kizaki S, Schneider M, Ziegler N, Hürlimann V, Hoeng J, Sierro N, Ivanov NV, Sturla SJ. Quantification and Mapping of Alkylation in the Human Genome Reveal Single Nucleotide Resolution Precursors of Mutational Signatures. ACS CENTRAL SCIENCE 2023; 9:362-372. [PMID: 36968528 PMCID: PMC10037492 DOI: 10.1021/acscentsci.2c01100] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Indexed: 06/18/2023]
Abstract
Chemical modifications to DNA bases, including DNA adducts arising from reactions with electrophilic chemicals, are well-known to impact cell growth, miscode during replication, and influence disease etiology. However, knowledge of how genomic sequences and structures influence the accumulation of alkylated DNA bases is not broadly characterized with high resolution, nor have these patterns been linked with overall quantities of modified bases in the genome. For benzo(a) pyrene (BaP), a ubiquitous environmental carcinogen, we developed a single-nucleotide resolution damage sequencing method to map in a human lung cell line the main mutagenic adduct arising from BaP. Furthermore, we combined this analysis with quantitative mass spectrometry to evaluate the dose-response profile of adduct formation. By comparing damage abundance with DNase hypersensitive sites, transcription levels, and other genome annotation data, we found that although overall adduct levels rose with increasing chemical exposure concentration, genomic distribution patterns consistently correlated with chromatin state and transcriptional status. Moreover, due to the single nucleotide resolution characteristics of this DNA damage map, we could determine preferred DNA triad sequence contexts for alkylation accumulation, revealing a characteristic DNA damage signature. This new BaP damage signature had a profile highly similar to mutational signatures identified previously in lung cancer genomes from smokers. Thus, these data provide insight on how genomic features shape the accumulation of alkylation products in the genome and predictive strategies for linking single-nucleotide resolution in vitro damage maps with human cancer mutations.
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Affiliation(s)
- Yang Jiang
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Cécile Mingard
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Sabrina M. Huber
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Vakil Takhaveev
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Maureen McKeague
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, Zurich 8092, Switzerland
- Pharmacology
and Therapeutics, Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Seiichiro Kizaki
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Mirjam Schneider
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Nathalie Ziegler
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Vera Hürlimann
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Julia Hoeng
- Philip
Morris Products SA, Quai
Jeanrenaud 3, Neuchatel 2000, Switzerland
| | - Nicolas Sierro
- Philip
Morris Products SA, Quai
Jeanrenaud 3, Neuchatel 2000, Switzerland
| | - Nikolai V. Ivanov
- Philip
Morris Products SA, Quai
Jeanrenaud 3, Neuchatel 2000, Switzerland
| | - Shana J. Sturla
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, Zurich 8092, Switzerland
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11
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Ding X, Pu Y, Tang M, Zhang T. Pulmonary hazard identifications of Graphene family nanomaterials: Adverse outcome pathways framework based on toxicity mechanisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159329. [PMID: 36216050 DOI: 10.1016/j.scitotenv.2022.159329] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 10/05/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
Graphene-family nanomaterials (GFNs) are revolutionary new nanomaterials that have attracted significant attention in the field of nanomaterials, but the ensuing problems lie in the potential threats to public health and the ecosystem caused by these nanomaterials. From the perspective of GFN-related health risk assessments, this study reviews the current status of GFN-induced pathological lung events with a focus on the damage caused to different biological moieties (molecular, cellular, tissue, and organ) and the mechanistic relationships between different toxic endpoints. These multiple sites of damage were matched with existing adverse outcome pathways (AOPs) in an online knowledge base to obtain available molecular initiation events (MIEs), key events (KEs), and adverse outcomes (AOs). Among them, the MIEs were discussed in combination with the structure-activity relationship due to the correlation between toxicity and physical and chemical properties of GFNs. Based on the collection of information regarding MIEs, Kes, and AOs in addition to upstream and downstream causal extrapolation, the AOP framework for GFN-induced pulmonary toxicity was developed, highlighting the possible mechanisms of GFN-induced lung damage. This review intended to combine AOP with classic toxicological methods with a view to rapidly and accurately establishing a nanotoxicology infrastructure so as to contribute to public health risk assessment strategies through iteration from and animal models up to the population level.
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Affiliation(s)
- Xiaomeng Ding
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Yuepu Pu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Meng Tang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Ting Zhang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China.
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12
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Abstract
DNA damage by chemicals, radiation, or oxidative stress leads to a mutational spectrum, which is complex because it is determined in part by lesion structure, the DNA sequence context of the lesion, lesion repair kinetics, and the type of cells in which the lesion is replicated. Accumulation of mutations may give rise to genetic diseases such as cancer and therefore understanding the process underlying mutagenesis is of immense importance to preserve human health. Chemical or physical agents that cause cancer often leave their mutational fingerprints, which can be used to back-calculate the molecular events that led to disease. To make a clear link between DNA lesion structure and the mutations a given lesion induces, the field of single-lesion mutagenesis was developed. In the last three decades this area of research has seen much growth in several directions, which we attempt to describe in this Perspective.
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Affiliation(s)
- Ashis K Basu
- Department of Chemistry, The University of Connecticut Storrs, Storrs, Connecticut 06269, United States
| | - John M Essigmann
- Departments of Chemistry, Biological Engineering and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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13
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Aralov AV, Gubina N, Cabrero C, Tsvetkov VB, Turaev AV, Fedeles BI, Croy RG, Isaakova EA, Melnik D, Dukova S, Ryazantsev DY, Khrulev AA, Varizhuk AM, González C, Zatsepin TS, Essigmann JM. 7,8-Dihydro-8-oxo-1,N6-ethenoadenine: an exclusively Hoogsteen-paired thymine mimic in DNA that induces A→T transversions in Escherichia coli. Nucleic Acids Res 2022; 50:3056-3069. [PMID: 35234900 PMCID: PMC8989528 DOI: 10.1093/nar/gkac148] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 02/09/2022] [Accepted: 02/25/2022] [Indexed: 12/15/2022] Open
Abstract
This work investigated the structural and biological properties of DNA containing 7,8-dihydro-8-oxo-1,N6-ethenoadenine (oxo-ϵA), a non-natural synthetic base that combines structural features of two naturally occurring DNA lesions (7,8-dihydro-8-oxoadenine and 1,N6-ethenoadenine). UV-, CD-, NMR spectroscopies and molecular modeling of DNA duplexes revealed that oxo-ϵA adopts the non-canonical syn conformation (χ = 65º) and fits very well among surrounding residues without inducing major distortions in local helical architecture. The adduct remarkably mimics the natural base thymine. When considered as an adenine-derived DNA lesion, oxo-ϵA was >99% mutagenic in living cells, causing predominantly A→T transversion mutations in Escherichia coli. The adduct in a single-stranded vector was not repaired by base excision repair enzymes (MutM and MutY glycosylases) or the AlkB dioxygenase and did not detectably affect the efficacy of DNA replication in vivo. When the biological and structural data are viewed together, it is likely that the nearly exclusive syn conformation and thymine mimicry of oxo-ϵA defines the selectivity of base pairing in vitro and in vivo, resulting in lesion pairing with A during replication. The base pairing properties of oxo-ϵA, its strong fluorescence and its invisibility to enzymatic repair systems in vivo are features that are sought in novel DNA-based probes and modulators of gene expression.
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Affiliation(s)
- Andrey V Aralov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow 117997, Russia
| | - Nina Gubina
- Department of Biological Engineering, Department of Chemistry and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Institute of Theoretical and Experimental Biophysics RAS, Pushchino 142290, Russia
| | - Cristina Cabrero
- Instituto de Química-Física Rocasolano (IQFR-CSIC), Madrid 28006, Spain
| | - Vladimir B Tsvetkov
- Federal Research and Clinical Center of Physical Chemical Medicine of Federal Medical Biological Agency, Moscow 119435, Russia.,World-Class Research Center "Digital biodesign and personalized healthcare", Sechenov First Moscow State Medical University, Moscow 119146, Russia
| | - Anton V Turaev
- Federal Research and Clinical Center of Physical Chemical Medicine of Federal Medical Biological Agency, Moscow 119435, Russia
| | - Bogdan I Fedeles
- Department of Biological Engineering, Department of Chemistry and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert G Croy
- Department of Biological Engineering, Department of Chemistry and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ekaterina A Isaakova
- Federal Research and Clinical Center of Physical Chemical Medicine of Federal Medical Biological Agency, Moscow 119435, Russia
| | - Denis Melnik
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow 143026, Russia
| | - Svetlana Dukova
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow 143026, Russia
| | - Dmitriy Y Ryazantsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow 117997, Russia
| | - Alexei A Khrulev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow 117997, Russia
| | - Anna M Varizhuk
- Federal Research and Clinical Center of Physical Chemical Medicine of Federal Medical Biological Agency, Moscow 119435, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Carlos González
- Instituto de Química-Física Rocasolano (IQFR-CSIC), Madrid 28006, Spain
| | - Timofei S Zatsepin
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow 143026, Russia.,Chemistry Department, Lomonosov Moscow State University, Moscow 119992, Russia
| | - John M Essigmann
- Department of Biological Engineering, Department of Chemistry and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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14
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Sonohara Y, Takatsuka R, Masutani C, Iwai S, Kuraoka I. Acetaldehyde induces NER repairable mutagenic DNA lesions. Carcinogenesis 2021; 43:52-59. [PMID: 34546339 DOI: 10.1093/carcin/bgab087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 11/13/2022] Open
Abstract
Nucleotide excision repair (NER) is a repair mechanism that removes DNA lesions induced by UV radiation, environmental mutagens, and carcinogens. There exists sufficient evidence against acetaldehyde suggesting it to cause a variety of DNA lesions and be carcinogenic to humans. Previously, we found that acetaldehyde induces reversible intra-strand GG crosslinks in DNA similar to those induced by cis-diammineplatinum(II) that is subsequently repaired by NER. In this study, we analysed the repairability by NER mechanism and the mutagenesis of acetaldehyde. In an in vitro reaction setup with NER-proficient and NER-deficient xeroderma pigmentosum group A (XPA) cell extracts, NER reactions were observed in the presence of XPA recombinant proteins in acetaldehyde-treated plasmids. Using an in vivo assay with living XPA cells and XPA-correcting XPA cells, the repair reactions were also observed. Additionally, it was observed that DNA polymerase eta inserted dATP opposite guanine in acetaldehyde-treated oligonucleotides, suggesting that acetaldehyde induced GG to TT transversions. These findings show that acetaldehyde induces NER repairable mutagenic DNA lesions.
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Affiliation(s)
- Yuina Sonohara
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Reine Takatsuka
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Chikahide Masutani
- Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Shigenori Iwai
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Isao Kuraoka
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.,Department of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
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15
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Menzies GE, Prior IA, Brancale A, Reed SH, Lewis PD. Carcinogen-induced DNA structural distortion differences in the RAS gene isoforms; the importance of local sequence. BMC Chem 2021; 15:51. [PMID: 34521464 PMCID: PMC8439098 DOI: 10.1186/s13065-021-00777-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 08/17/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Local sequence context is known to have an impact on the mutational pattern seen in cancer. The RAS genes and a smoking carcinogen, Benzo[a]pyrene diol epoxide (BPDE), have been utilised to explore these context effects. BPDE is known to form an adduct at the guanines in a number of RAS gene sites, KRAS codons 12, 13 and 14, NRAS codon 12, and HRAS codons 12 and 14. RESULTS Molecular modelling techniques, along with multivariate analysis, have been utilised to determine the sequence influenced differences between BPDE-adducted RAS gene sequences as well as the local distortion caused by the adducts. CONCLUSIONS We conclude that G:C > T:A mutations at KRAS codon 12 in the tumours of lung cancer patients (who smoke), proposed to be predominantly caused by BPDE, are due to the effect of the interaction methyl group at the C5 position of the thymine base in the KRAS sequence with the BPDE carcinogen investigated causing increased distortion. We further suggest methylated cytosine would have a similar effect, showing the importance of methylation in cancer development.
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Affiliation(s)
- Georgina E Menzies
- School of Biosciences and Dementia Research Institute at Cardiff, Cardiff University, Cardiff, CF10 3NX, UK.
| | - Ian A Prior
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3BX, UK
| | - Andrea Brancale
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, CF10 3NB, UK
| | - Simon H Reed
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK
| | - Paul D Lewis
- School of Management, Swansea University Bay Campus, Swansea, SA1 8EN, UK
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16
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Qi R, Bian K, Chen F, Tang Q, Zhou X, Li D. Sequence Dependent Repair of 1, N6-Ethenoadenine by DNA Repair Enzymes ALKBH2, ALKBH3, and AlkB. Molecules 2021; 26:molecules26175285. [PMID: 34500720 PMCID: PMC8434105 DOI: 10.3390/molecules26175285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/17/2021] [Accepted: 08/25/2021] [Indexed: 11/16/2022] Open
Abstract
Mutation patterns of DNA adducts, such as mutational spectra and signatures, are useful tools for diagnostic and prognostic purposes. Mutational spectra of carcinogens derive from three sources: adduct formation, replication bypass, and repair. Here, we consider the repair aspect of 1,N6-ethenoadenine (εA) by the 2-oxoglutarate/Fe(II)-dependent AlkB family enzymes. Specifically, we investigated εA repair across 16 possible sequence contexts (5'/3' flanking base to εA varied as G/A/T/C). The results revealed that repair efficiency is altered according to sequence, enzyme, and strand context (ss- versus ds-DNA). The methods can be used to study other aspects of mutational spectra or other pathways of repair.
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17
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Groopman JD, Smith JW, Rivera-Andrade A, Alvarez CS, Kroker-Lobos MF, Egner PA, Gharzouzi E, Dean M, McGlynn KA, Ramírez-Zea M. Aflatoxin and the Etiology of Liver Cancer and Its Implications for Guatemala. WORLD MYCOTOXIN J 2021; 14:305-317. [PMID: 35096197 PMCID: PMC8797158 DOI: 10.3920/wmj2020.2641] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
During the 60 years since the first scientific reports about a relation between aflatoxin exposure and adverse health consequences, both in animals and humans, there has been a remarkable number of basic, clinical and population science studies characterizing the impact of this mycotoxin on diseases such as liver cancer. Many of these human investigations to date have focused on populations residing in Asia and Africa due to the high incidence of liver cancer and high exposures to aflatoxin. These studies formed the basis for the International Agency for Research on Cancer to classify the aflatoxins as Group 1 known human carcinogens. In addition, aflatoxin contamination levels have been used in international commodity trade to set the price of various staples such as maize and groundnuts. While there have been many case-control and prospective cohort studies of liver cancer risk over the years there have been remarkably few investigations focused on liver cancer in Latin America. Our interdisciplinary and multiple institutional collaborative has been developing a long-term strategy to characterize the role of aflatoxin and other mycotoxins as health risk factors in Guatemala and neighboring countries. This paper summarizes a number of the investigations to date and provides a roadmap of our strategies for the near term to discern the emergent etiology of liver cancer in this region. With these data in hand public health-based prevention strategies could be strategically implemented and conducted to lower the impact of these mycotoxins on human health.
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Affiliation(s)
- John D. Groopman
- Departments of Environmental Health and Engineering and Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, U.S.A
| | - Joshua W. Smith
- Departments of Environmental Health and Engineering and Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, U.S.A
| | - Alvaro Rivera-Andrade
- INCAP Research Center for the Prevention of Chronic Diseases, Institute of Nutrition of Central America and Panama, Guatemala City, Guatemala
| | - Christian S. Alvarez
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, U.S.A
| | - María F. Kroker-Lobos
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, U.S.A
| | - Patricia A. Egner
- Departments of Environmental Health and Engineering and Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, U.S.A
| | | | - Michael Dean
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, U.S.A
| | - Katherine A. McGlynn
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, U.S.A
| | - Manuel Ramírez-Zea
- INCAP Research Center for the Prevention of Chronic Diseases, Institute of Nutrition of Central America and Panama, Guatemala City, Guatemala
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18
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Qiu T, Wang H, Yang Y, Yu J, Ji J, Sun J, Zhang S, Sun X. Exploration of biodegradation mechanism by AFB1-degrading strain Aspergillus niger FS10 and its metabolic feedback. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107609] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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19
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Kim W, Zhao F, Gao H, Qin S, Hou J, Deng M, Kloeber JA, Huang J, Zhou Q, Guo G, Gao M, Zeng X, Zhu S, Tu X, Wu Z, Zhang Y, Yin P, Kaufmann SH, Luo K, Lou Z. USP13 regulates the replication stress response by deubiquitinating TopBP1. DNA Repair (Amst) 2021; 100:103063. [PMID: 33592542 DOI: 10.1016/j.dnarep.2021.103063] [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: 11/03/2020] [Revised: 01/19/2021] [Accepted: 02/03/2021] [Indexed: 10/22/2022]
Abstract
The DNA replication stress-induced checkpoint activated through the TopBP1-ATR axis is important for maintaining genomic stability. However, the regulation of TopBP1 in DNA-damage responses remains unclear. In this study, we identify the deubiquitinating enzyme (DUB) USP13 as an important regulator of TopBP1. Mechanistically, USP13 binds to TopBP1 and stabilizes TopBP1 by deubiquitination. Depletion of USP13 impedes ATR activation and hypersensitizes cells to replication stress-inducing agents. Furthermore, high USP13 expression enhances the replication stress response, promotes cancer cell chemoresistance, and is correlated with poor prognosis of cancer patients. Overall, these findings suggest that USP13 is a novel deubiquitinating enzyme for TopBP1 and coordinates the replication stress response.
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Affiliation(s)
- Wootae Kim
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Fei Zhao
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Huanyao Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Sisi Qin
- Department of Pathology, University of Chicago, Chicago, IL, 60637, USA
| | - Jing Hou
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Min Deng
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jake A Kloeber
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA; Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA; Mayo Clinic Medical Scientist Training Program, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jinzhou Huang
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Qin Zhou
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Guijie Guo
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Ming Gao
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Xiangyu Zeng
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Shouhai Zhu
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Xinyi Tu
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Zheming Wu
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Yong Zhang
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Ping Yin
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Scott H Kaufmann
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Kuntian Luo
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Zhenkun Lou
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA; Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA.
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20
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Pathira Kankanamge LS, Perera HM, Griffin WC. Genome Repair Takes a Spotlight during the ACS TOXI Meeting. Chem Res Toxicol 2021; 34:675-677. [PMID: 33508200 DOI: 10.1021/acs.chemrestox.0c00438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
DNA damage and mutations are a major primary cause of cancer. Chemical bombardment of DNA is a major contributor to DNA damage. The Division of Chemical Toxicology recently hosted a panel of researchers who provided updates on the field of chemical toxicology at the nexus of DNA damage and repair.
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Affiliation(s)
- Lakindu S Pathira Kankanamge
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Himasha M Perera
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Wezley C Griffin
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
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21
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Byrne SR, Rokita SE. Unraveling Reversible DNA Cross-Links with a Biological Machine. Chem Res Toxicol 2020; 33:2903-2913. [PMID: 33147957 DOI: 10.1021/acs.chemrestox.0c00413] [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
The reversible generation and capture of certain electrophilic quinone methide intermediates support dynamic reactions with DNA that allow for migration and transfer of alkylation and cross-linking. This reversibility also expands the possible consequences that can be envisioned when confronted by DNA repair processes and biological machines. To begin testing the response to such an encounter, quinone methide-based modification of DNA has now been challenged with a helicase (T7 bacteriophage gene protein four, T7gp4) that promotes 5' to 3' translocation and unwinding. This model protein was selected based on its widespread application, well characterized mechanism and detailed structural information. Little over one-half of the cross-linking generated by a bisfunctional quinone methide remained stable to T7gp4 and did not suppress its activity. The helicase likely avoids the topological block generated by this fraction of cross-linking by its ability to shift from single- to double-stranded translocation. The remaining fraction of cross-linking was destroyed during T7gp4 catalysis. Thus, this helicase is chemically competent to promote release of the quinone methide from DNA. The ability of T7gp4 to act as a Brownian ratchet for unwinding DNA may block recapture of the QM intermediate by DNA during its transient release from a donor strand. Most surprisingly, T7gp4 releases the quinone methide from both the translocating strand that passes through its central channel and the excluded strand that was typically unaffected by other lesions. The ability of T7gp4 to reverse the cross-link formed by the quinone methide does not extend to that formed irreversibly by the nitrogen mustard mechlorethamine.
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Affiliation(s)
- Shane R Byrne
- Chemistry Biology Interface Graduate Training Program and Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States
| | - Steven E Rokita
- Chemistry Biology Interface Graduate Training Program and Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States
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22
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Abstract
Environmental exposures have long been known to impact public health and safety. For example, exposures to airborne particulates, heavy metals in water, or certain industrial chemicals can contribute to aging and to risk of developing cancer and other diseases. Environmental factors can impact health in a variety of ways, but a key concern is DNA damage, which can lead to mutations that cause cancer. Cancer can take years to develop following chemical exposure; however, one way to predict carcinogenicity in a more practical time frame is by studying the chemical's ability to induce DNA damage. The comet assay (or single-cell gel electrophoresis assay) has been used successfully for genotoxicity testing. The comet assay allows for the detection of DNA strand breaks via analysis of DNA migration during electrophoresis. Previously, the Engelward laboratory, in collaboration with the Bhatia laboratory, developed the CometChip for measurements of DNA damage and repair. The CometChip is a high-throughput comet assay that improves user reproducibility and significantly shortens total assay time. Here, we describe how the high-throughput CometChip platform can be used to measure DNA damage in established cell lines, animal models, and human samples. We also discuss technical challenges associated with these studies and provide recommendations on how to achieve optimal results for researchers interested in adopting this assay.
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Affiliation(s)
- Christy Chao
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, Massachusetts, United States
| | - Bevin P. Engelward
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, Massachusetts, United States
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23
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Rodriguez-Alvarez M, Kim D, Khobta A. EGFP Reporters for Direct and Sensitive Detection of Mutagenic Bypass of DNA Lesions. Biomolecules 2020; 10:biom10060902. [PMID: 32545792 PMCID: PMC7357151 DOI: 10.3390/biom10060902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/05/2020] [Accepted: 06/10/2020] [Indexed: 02/06/2023] Open
Abstract
The sustainment of replication and transcription of damaged DNA is essential for cell survival under genotoxic stress; however, the damage tolerance of these key cellular functions comes at the expense of fidelity. Thus, translesion DNA synthesis (TLS) over damaged nucleotides is a major source of point mutations found in cancers; whereas erroneous bypass of damage by RNA polymerases may contribute to cancer and other diseases by driving accumulation of proteins with aberrant structure and function in a process termed “transcriptional mutagenesis” (TM). Here, we aimed at the generation of reporters suited for direct detection of miscoding capacities of defined types of DNA modifications during translesion DNA or RNA synthesis in human cells. We performed a systematic phenotypic screen of 25 non-synonymous base substitutions in a DNA sequence encoding a functionally important region of the enhanced green fluorescent protein (EGFP). This led to the identification of four loss-of-fluorescence mutants, in which any ulterior base substitution at the nucleotide affected by the primary mutation leads to the reversal to a functional EGFP. Finally, we incorporated highly mutagenic abasic DNA lesions at the positions of primary mutations and demonstrated a high sensitivity of detection of the mutagenic DNA TLS and TM in this system.
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Affiliation(s)
- Marta Rodriguez-Alvarez
- Unit “Responses to DNA Lesions", Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, 55131 Mainz, Germany;
| | - Daria Kim
- Novosibirsk State University, 1 Pirogova St., 630090 Novosibirsk, Russia;
- Laboratory of Genome and Protein Engineering, SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Andriy Khobta
- Unit “Responses to DNA Lesions", Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, 55131 Mainz, Germany;
- Correspondence:
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24
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Thongararm P, Fedeles BI, Khumsubdee S, Armijo AL, Kim L, Thiantanawat A, Promvijit J, Navasumrit P, Ruchirawat M, Croy RG, Essigmann JM. Modulation of N-Methyl- N-nitrosourea Mutagenesis in Mouse Embryo Fibroblasts Derived from the gpt Delta Mouse by an Inhibitor of the O6-Methylguanine Methyltransferase, MGMT. Chem Res Toxicol 2020; 33:625-633. [PMID: 31841318 PMCID: PMC7033946 DOI: 10.1021/acs.chemrestox.9b00444] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
DNA methylating agents are abundant in the environment and are sometimes used in cancer chemotherapy. They react with DNA to form methyl-DNA adducts and byproduct lesions that can be both toxic and mutagenic. Foremost among the mutagenic lesions is O6-methylguanine (m6G), which base pairs with thymine during replication to cause GC → AT mutations. The gpt delta C57BL/6J mouse strain of Nohmi et al. (Mol. Mutagen 1996, 28, 465-70) reliably produces mutational spectra of many DNA damaging agents. In this work, mouse embryo fibroblasts (MEFs) were made from gpt delta C57BL/6J mice and evaluated as a screening tool to determine the qualitative and quantitative features of mutagenesis by N-methyl-N-nitrosourea (MNU), a direct-acting DNA alkylator that serves as a model for environmental N-nitrosamines, such as N-nitrosodimethylamine and therapeutic agents such as Temozolomide. The DNA repair protein MGMT (O6-methylguanine DNA methyltransferase) protects against environmental mutagenesis by DNA methylating agents and, by removing m6G, limits the therapeutic potential of Temozolomide in cancer therapy. The gpt delta MEFs were treated with MNU to establish dose-dependent toxicity. In parallel, MNU mutagenicity was determined in the presence and absence of the MGMT inhibitor AA-CW236 (4-(2-(5-(chloromethyl)-4-(4-(trifluoromethoxy)phenyl)-1H-1,2,3-triazol-1-yl)ethyl)-3,5-dimethylisoxazole). With and without the inhibitor, the principal mutagenic event of MNU was GC → AT, but more mutations were observed when the inhibitor was present. Evidence that the mutagenic lesion was m6G was based on mass spectral data collected using O6-methyl-d3-guanine as an internal standard; m6G levels were higher in AA-CW236 treated MEFs by an amount proportional to the higher mutation frequency seen in the same cells. This work establishes gpt delta MEFs as a versatile tool for probing mutagenesis by environmental and therapeutic agents and as a cell culture model in which chemical genetics can be used to determine the impact of DNA repair on biological responses to DNA damaging agents.
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Affiliation(s)
- Pennapa Thongararm
- Departments of Biological Engineering and Chemistry, and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Chulabhorn Research Institute, Bangkok 10210, Thailand
| | - Bogdan I. Fedeles
- Departments of Biological Engineering and Chemistry, and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Sakunchai Khumsubdee
- Departments of Biological Engineering and Chemistry, and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Chulabhorn Research Institute, Bangkok 10210, Thailand
| | - Amanda L. Armijo
- Departments of Biological Engineering and Chemistry, and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Lina Kim
- Departments of Biological Engineering and Chemistry, and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | | | | | | | - Robert G. Croy
- Departments of Biological Engineering and Chemistry, and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - John M. Essigmann
- Departments of Biological Engineering and Chemistry, and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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25
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Hanawalt P, Sweasy J. Mechanistic understanding of cellular responses to genomic stress. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:25-33. [PMID: 31793074 DOI: 10.1002/em.22349] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 06/10/2023]
Abstract
Within the past half century we have learned of multiple pathways for repairing damaged DNA, based upon the intrinsic redundancy of information in its complementary double strands. Mechanistic details of these pathways have provided insights into environmental and endogenous threats to genomic stability. Studies on bacterial responses to ultraviolet light led to the discovery of excision repair, as well as the inducible SOS response to DNA damage. Similar responses in eukaryotes promote upregulation of error-prone translesion DNA polymerases. Recent advances in this burgeoning field include duplex DNA sequencing to provide strikingly accurate profiling of mutational signatures, analyses of gene expression patterns in single cells, CRISPR/Cas9 to generate changes at precise genomic positions, novel roles for RNA in gene expression and DNA repair, phase-separated aqueous environments for specialized cellular transactions, and DNA lesions as epigenetic signals for gene expression. The Environmental Mutagenesis and Genomics Society (EMGS), through the broad range of expertise in its membership, stands at the crossroad of basic understanding of mechanisms for genomic maintenance and the field of genetic toxicology, with the need for regulation of exposures to toxic substances. Our future challenges include devising strategies and technologies to identify individuals who are susceptible to specific genomic stresses, along with basic research on the underlying mechanisms of cellular stress responses that promote disease-causing mutations. As the science moves forward it should also be a responsibility for the EMGS to expand its outreach programs for the enlightenment and benefit of all humans and the biosphere. Environ. Mol. Mutagen. 61:25-33, 2020. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Philip Hanawalt
- Department of Biology, Stanford University, Stanford, California
| | - Joann Sweasy
- University of Arizona Cancer Center, Tucson, Arizona
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26
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Biological Evaluation of DNA Biomarkers in a Chemically Defined and Site-Specific Manner. TOXICS 2019; 7:toxics7020036. [PMID: 31242562 PMCID: PMC6631660 DOI: 10.3390/toxics7020036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 02/06/2023]
Abstract
As described elsewhere in this Special Issue on biomarkers, much progress has been made in the detection of modified DNA within organisms at endogenous and exogenous levels of exposure to chemical species, including putative carcinogens and chemotherapeutic agents. Advances in the detection of damaged or unnatural bases have been able to provide correlations to support or refute hypotheses between the level of exposure to oxidative, alkylative, and other stresses, and the resulting DNA damage (lesion formation). However, such stresses can form a plethora of modified nucleobases, and it is therefore difficult to determine the individual contribution of a particular modification to alter a cell's genetic fate, as measured in the form of toxicity by stalled replication past the damage, by subsequent mutation, and by lesion repair. Chemical incorporation of a modification at a specific site within a vector (site-specific mutagenesis) has been a useful tool to deconvolute what types of damage quantified in biologically relevant systems may lead to toxicity and/or mutagenicity, thereby allowing researchers to focus on the most relevant biomarkers that may impact human health. Here, we will review a sampling of the DNA modifications that have been studied by shuttle vector techniques.
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27
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Minko IG, Vartanian VL, Tozaki NN, Linde OK, Jaruga P, Coskun SH, Coskun E, Qu C, He H, Xu C, Chen T, Song Q, Jiao Y, Stone MP, Egli M, Dizdaroglu M, McCullough AK, Lloyd RS. Characterization of rare NEIL1 variants found in East Asian populations. DNA Repair (Amst) 2019; 79:32-39. [PMID: 31100703 DOI: 10.1016/j.dnarep.2019.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 04/30/2019] [Accepted: 05/01/2019] [Indexed: 10/26/2022]
Abstract
The combination of chronic dietary exposure to the fungal toxin, aflatoxin B1 (AFB1), and hepatitis B viral (HBV) infection is associated with an increased risk for early onset hepatocellular carcinomas (HCCs). An in-depth knowledge of the mechanisms driving carcinogenesis is critical for the identification of genetic risk factors affecting the susceptibility of individuals who are HBV infected and AFB1 exposed. AFB1-induced mutagenesis is characterized by G to T transversions. Hence, the DNA repair pathways that function on AFB1-induced DNA adducts or base damage from HBV-induced inflammation are anticipated to have a strong role in limiting carcinogenesis. These pathways define the mutagenic burden in the target tissues and ultimately limit cellular progression to cancer. Murine data have demonstrated that NEIL1 in the DNA base excision repair pathway was significantly more important than nucleotide excision repair relative to elevated risk for induction of HCCs. These data suggest that deficiencies in NEIL1 could contribute to the initiation of HCCs in humans. To investigate this hypothesis, publicly-available data on variant alleles of NEIL1 were analyzed and compared with genome sequencing data from HCC tissues derived from individuals residing in Qidong County (China). Three variant alleles were identified and the corresponding A51V, P68H, and G245R enzymes were characterized for glycosylase activity on genomic DNA containing a spectrum of oxidatively-induced base damage and an oligodeoxynucleotide containing a site-specific AFB1-formamidopyrimidine guanine adduct. Although the efficiency of the P68H variant was modestly decreased, the A51V and G245R variants showed nearly wild-type activities. Consistent with biochemical findings, molecular modeling of these variants demonstrated only slight local structural alterations. However, A51V was highly temperature sensitive suggesting that its biological activity would be greatly reduced. Overall, these studies have direct human health relevance pertaining to genetic risk factors and biochemical pathways previously not recognized as germane to induction of HCCs.
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Affiliation(s)
- Irina G Minko
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States
| | - Vladimir L Vartanian
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States
| | - Naoto N Tozaki
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States
| | - Oskar K Linde
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States
| | - Pawel Jaruga
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States
| | - Sanem Hosbas Coskun
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States
| | - Erdem Coskun
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States
| | - Chunfeng Qu
- State Key Lab of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Huan He
- State Key Lab of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Chungui Xu
- State Key Lab of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Taoyang Chen
- Qidong Liver Cancer Institute & Qidong People's Hospital, Qidong, 226200, Jiangsu Province, China
| | - Qianqian Song
- State Key Lab of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Yuchen Jiao
- State Key Lab of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Michael P Stone
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, United States
| | - Martin Egli
- Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, United States
| | - Miral Dizdaroglu
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States
| | - Amanda K McCullough
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States; Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, 97239, United States
| | - R Stephen Lloyd
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States; Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, 97239, United States; Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, 97239, United States.
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28
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McCullough AK, Lloyd RS. Mechanisms underlying aflatoxin-associated mutagenesis - Implications in carcinogenesis. DNA Repair (Amst) 2019; 77:76-86. [PMID: 30897375 PMCID: PMC6959417 DOI: 10.1016/j.dnarep.2019.03.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/01/2019] [Accepted: 03/05/2019] [Indexed: 01/07/2023]
Abstract
Chronic dietary exposure to aflatoxin B1 (AFB1), concomitant with hepatitis B infection is associated with a significant increased risk for hepatocellular carcinomas (HCCs) in people living in Southeast Asia and sub-Saharan Africa. Human exposures to AFB1 occur through the consumption of foods that are contaminated with pervasive molds, including Aspergillus flavus. Even though dietary exposures to aflatoxins constitute the second largest global environmental risk factor for cancer development, there are still significant questions concerning the molecular mechanisms driving carcinogenesis and what factors may modulate an individual's risk for HCC. The objective of this review is to summarize key discoveries that established the association of chronic inflammation (most commonly associated with hepatitis B viral (HBV) infection) and environmental exposures to aflatoxin with increased HCC risk. Special emphasis will be given to recent investigations that have: 1) refined the aflatoxin-associated mutagenic signature, 2) expanded the DNA repair mechanisms that limit mutagenesis via adduct removal prior to replication-induced mutagenesis, 3) implicated a specific DNA polymerase in the error-prone bypass and resulting mutagenesis, and 4) identified human polymorphic variants that may modulate individual susceptibility to aflatoxin-induced cancers. Collectively, these investigations revealed that specific sequence contexts are differentially resistant against, or prone to, aflatoxin-induced mutagenesis and that these associations are remarkably similar between in vitro and in vivo analyses. These recent investigations also established DNA polymerase ζ as the major polymerase that confers the G to T transversion signature. Additionally, although the nucleotide excision repair (NER) pathway has been previously shown to repair aflatoxin-induced DNA adducts, recent murine data demonstrated that NEIL1-initiated base excision repair was significantly more important than NER relative to the removal of the highly mutagenic AFB1-Fapy-dG adducts. These data suggest that inactivating polymorphic variants of NEIL1 could be a potential driver of HCCs in aflatoxin-exposed populations.
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Affiliation(s)
- Amanda K McCullough
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, United States; Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, United States
| | - R Stephen Lloyd
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, United States; Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, United States; Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97239, United States.
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29
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Qiu T, Shen X, Li X, Gong Y, Zou Z, Liu C, Ye F, Mi C, Xu Z, Sun Y, Lin J, Zhang H, Lei H. Egg Yolk Immunoglobulin Supplementation Prevents Rat Liver from Aflatoxin B 1-Induced Oxidative Damage and Genotoxicity. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:13260-13267. [PMID: 30449111 DOI: 10.1021/acs.jafc.8b04659] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Egg yolk immunoglobulins (IgY), as nutraceutical supplement for therapeutic or prophylactic intervention, have been extensively studied. The effects of IgY on small molecular toxin-induced toxicity in animals are unclear. In the present study, the protection of highly purified and specific anti-AFB1 IgY against AFB1-induced genotoxicity and oxidative damage on the rat liver model were investigated. Our results revealed that AFB1 induced significant oxidative damage markers, as well as AFB1-induced protein expression in antioxidant, pro- and antiapoptosis processes in rat liver. These effects could be significantly inhibited by cogavage with anti-AFB1 IgY in a dose-dependent manner. However, anti-AFB1 IgY did not significantly induce hepatic CAT and SOD1. To explore mechanisms, metabolite experiments were established to evaluate the influence of anti-AFB1 IgY on the absorption of AFB1 in rats. Middle and high doses of anti-AFB1 IgY reduced hepatic AFB1-DNA adducts by 43.3% and 52.9%, AFB1- N7-guanine urinary adducts by 19.6% and 34.4%, and AFB1-albumin adducts by 10.5% and 21.1%, respectively. The feces of high dose anti-AFB1 IgY cogavaged rats contained approximately 2-fold higher AFB1 equivalents at 3-6 h after ingestion than AFB1 group feces, indicating IgY inhibited AFB1 uptake. These results had provided insight that anti-AFB1 IgY could prevent animal organs from damage caused by AFB1 and will be beneficial for the application of detoxification antibody as a supplement in food.
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Affiliation(s)
- Taotao Qiu
- Guangdong Provincial Key Laboratory of Food Quality and Safety/College of Food Science , South China Agricultural University , Guangzhou 510642 , China
- Key Laboratory of Environment and Female Reproductive Health/Public Health Laboratory Sciences and Toxicology, West China School of Public Health , Sichuan University , Chengdu , China
| | - Xing Shen
- Guangdong Provincial Key Laboratory of Food Quality and Safety/College of Food Science , South China Agricultural University , Guangzhou 510642 , China
| | - Xiangmei Li
- Guangdong Provincial Key Laboratory of Food Quality and Safety/College of Food Science , South China Agricultural University , Guangzhou 510642 , China
| | - Yunyun Gong
- Department of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment , Ministry of Health , Beijing 100021 China
| | - Zhongmin Zou
- Institute of Toxicology, College of Preventive Medicine , Third Military Medical University , Chongqing , China
| | - Chunhong Liu
- Guangdong Provincial Key Laboratory of Food Quality and Safety/College of Food Science , South China Agricultural University , Guangzhou 510642 , China
| | - Feng Ye
- Institute of Toxicology, College of Preventive Medicine , Third Military Medical University , Chongqing , China
| | - Chenyang Mi
- Key Laboratory of Environment and Female Reproductive Health/Public Health Laboratory Sciences and Toxicology, West China School of Public Health , Sichuan University , Chengdu , China
| | - Zhenlin Xu
- Guangdong Provincial Key Laboratory of Food Quality and Safety/College of Food Science , South China Agricultural University , Guangzhou 510642 , China
| | - Yuanming Sun
- Guangdong Provincial Key Laboratory of Food Quality and Safety/College of Food Science , South China Agricultural University , Guangzhou 510642 , China
| | - Jie Lin
- Guangdong Provincial Key Laboratory of Food Quality and Safety/College of Food Science , South China Agricultural University , Guangzhou 510642 , China
| | - Huidong Zhang
- Key Laboratory of Environment and Female Reproductive Health/Public Health Laboratory Sciences and Toxicology, West China School of Public Health , Sichuan University , Chengdu , China
| | - Hongtao Lei
- Guangdong Provincial Key Laboratory of Food Quality and Safety/College of Food Science , South China Agricultural University , Guangzhou 510642 , China
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