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International Journal of Cancer Dec 2012Cigarette smoke is a complex mixture of chemicals including multiple genotoxic lung carcinogens. The classic mechanisms of carcinogen metabolic activation to DNA... (Review)
Review
Cigarette smoke is a complex mixture of chemicals including multiple genotoxic lung carcinogens. The classic mechanisms of carcinogen metabolic activation to DNA adducts, leading to miscoding and mutations in critical growth control genes, applies to this mixture but some aspects are difficult to establish because of the complexity of the exposure. This article discusses certain features of this mechanism including the role of nicotine and its receptors; lung carcinogens, co-carcinogens and related substances in cigarette smoke; structurally characterized DNA adducts in the lungs of smokers; the mutational consequences of DNA adduct formation in smokers' lungs; and biomarkers of nicotine and carcinogen uptake as related to lung cancer. While there are still uncertainties which may never be fully resolved, the general mechanisms by which cigarette smoking causes lung cancer are well understood and provide insights relevant to prevention of lung cancer, the number one cancer killer in the world, causing 1.37 million deaths per year.
Topics: Cell Transformation, Neoplastic; Cocarcinogenesis; DNA Adducts; Humans; Lung; Lung Neoplasms; Mutation; Nicotine; Smoke; Nicotiana
PubMed: 22945513
DOI: 10.1002/ijc.27816 -
Cancer Science Jan 2021Chemical carcinogenesis is focused on the formation of DNA adducts, a form of DNA damage caused by covalent binding of a chemical moiety to DNA. The detection of... (Review)
Review
Chemical carcinogenesis is focused on the formation of DNA adducts, a form of DNA damage caused by covalent binding of a chemical moiety to DNA. The detection of carcinogen-DNA adducts in human tissues, along with demonstration of mutagenicity/carcinogenicity in experimental systems, and validation of adducts as biomarkers of environmental exposure and indicators of cancer risk in molecular epidemiological studies suggests a pivotal role of DNA adducts in cancer development. However, accurate measurement of DNA adducts in varied biological samples is challenging. Advances in mass spectrometry have prompted the development of DNA adductome analysis, an emerging method that simultaneously screens for multiple DNA adducts and provides relevant structural information. In this review, we summarize the basic principle and applications of DNA adductome analysis that would contribute to the elucidation of the environmental causes of cancer. Based on parallel developments in several fields, including next-generation sequencing, we describe a new approach used to explore cancer etiology, which integrates analyses of DNA adductome data and mutational signatures derived from whole-genome/exome sequencing.
Topics: Animals; DNA; DNA Adducts; DNA Damage; Environmental Exposure; Humans; Mutation; Neoplasms
PubMed: 32978845
DOI: 10.1111/cas.14666 -
Current Opinion in Biotechnology Feb 2019Detection and characterization of DNA damage is essential for evaluating genotoxicity, monitoring DNA repair, developing biomarkers for exposures, and evaluating the... (Review)
Review
Detection and characterization of DNA damage is essential for evaluating genotoxicity, monitoring DNA repair, developing biomarkers for exposures, and evaluating the efficacy of chemotherapies. These diverse applications for DNA damage measurements have spurred the continual development and refinement of methodologies for detecting, characterizing, and quantifying DNA damage from isolated DNA and in cells and tissues. Current damage detection methods cover a wide range of techniques from radiolabeling to mass spectrometry, and use of these techniques varies widely based on expense, expertise, and knowledge of adduct formation. More generalizable, easy-to-use methods for detecting and quantifying DNA damage are needed, and there has been an emergence of fluorescence-based methodologies to address this need. Developments in these fluorescence-based strategies are reviewed here.
Topics: Biomarkers; DNA Adducts; DNA Damage; DNA Repair; Enzyme Assays; Fluorescence; Humans
PubMed: 30114673
DOI: 10.1016/j.copbio.2018.08.001 -
Analytical Chemistry Nov 2017Damage to DNA from the metabolites of drugs and pollutants constitutes a major human toxicity pathway known as genotoxicity. Metabolites can react with metal ions and...
Damage to DNA from the metabolites of drugs and pollutants constitutes a major human toxicity pathway known as genotoxicity. Metabolites can react with metal ions and NADPH to oxidize DNA or participate in S2 reactions to form covalently linked adducts with DNA bases. Guanines are the main DNA oxidation sites, and 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) is the initial product. Here we describe a novel electrochemiluminescent (ECL) microwell array that produces metabolites from test compounds and measures relative rates of DNA oxidation and DNA adduct damage. In this new array, films of DNA, metabolic enzymes, and an ECL metallopolymer or complex assembled in microwells on a pyrolytic graphite wafer are housed in dual microfluidic chambers. As reactant solution passes over the wells, metabolites form and can react with DNA in the films to form DNA adducts. These adducts are detected by ECL from a RuPVP polymer that uses DNA as a coreactant. Aryl amines also combine with Cu and NADPH to form reactive oxygen species (ROS) that oxidize DNA. The resulting 8-oxodG was detected selectively by ECL-generating bis(2,2'-bipyridine)-(4-(1,10-phenanthrolin-6-yl)-benzoic acid)Os(II). DNA/enzyme films on magnetic beads were oxidized similarly, and 8-oxodG determined by LC/MS/MS enabled array standardization. The array limit of detection for oxidation was 720 8-oxodG per 10 nucleobases. For a series of aryl amines, metabolite-generated DNA oxidation and adduct formation turnover rates from the array correlated very well with rodent 1/TD and Comet assay results.
Topics: Amines; Copper; Cytochrome P-450 Enzyme System; DNA; DNA Adducts; DNA Damage; Electrochemical Techniques; Humans; Luminescent Measurements; Microfluidic Analytical Techniques; NADP; Oxidation-Reduction
PubMed: 29083162
DOI: 10.1021/acs.analchem.7b03528 -
International Journal of Molecular... Jan 2023Studies have indicated that air pollution, including surface-level ozone (O), can significantly influence the risk of chronic diseases. To better understand the...
Studies have indicated that air pollution, including surface-level ozone (O), can significantly influence the risk of chronic diseases. To better understand the carcinogenic mechanisms of air pollutants and identify predictive disease biomarkers, we examined the association between traffic-related pollutants with DNA methylation alterations and bulky DNA adducts, two biomarkers of carcinogen exposure and cancer risk, in the peripheral blood of 140 volunteers-95 traffic police officers, and 45 unexposed subjects. The DNA methylation and adduct measurements were performed by bisulfite-PCR and pyrosequencing and P-postlabeling assay. Airborne levels of benzo(a)pyrene [B(a)P], carbon monoxide, and tropospheric O were determined by personal exposure biomonitoring or by fixed monitoring stations. Overall, air pollution exposure was associated with a significant reduction (1.41 units) in global DNA methylation (95% C.I. -2.65-0.04, = 0.026). The decrement in repetitive elements was greatest in the policemen working downtown (95% C.I. -3.23--0.49, = 0.008). The DNA adducts were found to be significantly increased (0.45 units) in the municipal officers with respect to unexposed subjects (95% C.I. 0.02-0.88, = 0.039), mainly in those who were controlling traffic in downtown areas (95% C.I. 0.39-1.29, < 0.001). Regression models indicated an increment of methylation at higher B(a)P concentrations (95% C.I. 0.03-0.60, = 0.032). Moreover, statistical models showed a decrement in methylation and an increment of DNA damage only above the cut-off value of 30 µg/m O. A significant increment of 0.73 units of gene methylation was also found in smokers with respect to non-smokers. Our results highlighted the role of air pollution on epigenetic alterations and genotoxic effects, especially above the target value of 30 µg/m surface-level O, supporting the necessity for developing public health strategies aimed to reduce traffic-related air pollution molecular alterations.
Topics: Humans; DNA Adducts; Ozone; DNA Damage; Air Pollutants; Air Pollution; Biomarkers
PubMed: 36768368
DOI: 10.3390/ijms24032041 -
Mutation Research Mar 1999Mycotoxins are toxic fungal metabolites which are structurally diverse, common contaminants of the ingredients of animal feed and human food. To date, mycotoxins with... (Review)
Review
Mycotoxins are toxic fungal metabolites which are structurally diverse, common contaminants of the ingredients of animal feed and human food. To date, mycotoxins with carcinogenic potency in experimental animal models include aflatoxins, sterigmatocystin, ochratoxin, fumonisins, zearalenone, and some Penicillium toxins. Most of these carcinogenic mycotoxins are genotoxic agents with the exception of fumonisins, which is currently believed to act by disrupting the signal transduction pathways of the target cells. Aflatoxin B1 (AFB1), a category I known human carcinogen and the most potent genotoxic agent, is mutagenic in many model systems and produces chromosomal aberrations, micronuclei, sister chromatid exchange, unscheduled DNA synthesis, and chromosomal strand breaks, as well as forms adducts in rodent and human cells. The predominant AFB1-DNA adduct was identified as 8, 9-dihydro-8-(N7-guanyl)-9-hydroxy-AFB1 (AFB1-N7-Gua), which derives from covalent bond formation between C8 of AFB1-8,9-epoxides and N7 of guanine bases in DNA. Initial AFB1-N7-guanine adduct can convert to a ring-opened formamidopyrimidine derivative, AFB1-FAPY. The formation of AFB1-N7-guanine adduct was linear over the low-dose range in all species examined, and liver, the primary target organ, had the highest level of the adduct. Formation of initial AFB1-N7-guanine adduct was correlated with the incidence of hepatic tumor in trout and rats. The AFB1-N7-guanine adduct was removed from DNA rapidly and was excreted exclusively in urine of exposed rats. Several human studies have validated the similar correlation between dietary exposure to AFB1 and excretion of AFB1-N7-guanine in urine. Replication of DNA containing AFB1-N7-guanine adduct-induced G-->T mutations in an experimental model. Activation of ras protooncogene has been found in AFB1-induced tumors in mouse, rat, and fish. More strikingly, the relationship between aflatoxin exposure and development of human hepatocellular carcinoma (HHC) was demonstrated by the studies on the p53 tumor suppressor gene. High frequency of p53 mutations (G-->T transversion at codon 249) was found to occur in HHC collected from populations exposed to high levels of dietary aflatoxin in China and Southern Africa. Furthermore, AFB1-induced DNA damage and hepatocarcinogenesis in experimental models can be modulated by a variety of factors including nutrients, chemopreventive agents, and other factors such as food restriction and viral infection, as well as genetic polymorphisms.
Topics: Aflatoxins; Africa, Southern; Animals; Carcinogens; China; DNA Adducts; DNA Damage; Diet; Humans; Mice; Mycotoxins; Rats
PubMed: 10064859
DOI: 10.1016/s0027-5107(99)00017-2 -
The Analyst Oct 2016Exposure to chemical pollutants and pharmaceuticals may cause health issues caused by metabolite-related toxicity. This paper reports a new microfluidic electrochemical...
Exposure to chemical pollutants and pharmaceuticals may cause health issues caused by metabolite-related toxicity. This paper reports a new microfluidic electrochemical sensor array with the ability to simultaneously detect common types of DNA damage including oxidation and nucleobase adduct formation. Sensors in the 8-electrode screen-printed carbon array were coated with thin films of metallopolymers osmium or ruthenium bipyridyl-poly(vinylpyridine) chloride (OsPVP, RuPVP) along with DNA and metabolic enzymes by layer-by-layer electrostatic assembly. After a reaction step in which test chemicals and other necessary reagents flow over the array, OsPVP selectively detects oxidized guanines on the DNA strands, and RuPVP detects DNA adduction by metabolites on nucleobases. We demonstrate array performance for test chemicals including 17β-estradiol (E), its metabolites 4-hydroxyestradiol (4-OHE), 2-hydroxyestradiol (2-OHE), catechol, 2-nitrosotoluene (2-NO-T), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and 2-acetylaminofluorene (2-AAF). Results revealed DNA-adduct and oxidation damage in a single run to provide a metabolic-genotoxic chemistry screen. The array measures damage directly in unhydrolyzed DNA, and is less expensive, faster, and simpler than conventional methods to detect DNA damage. The detection limit for oxidation is 672 8-oxodG per 10 bases. Each sensor requires only 22 ng of DNA, so the mass detection limit is 15 pg (∼10 pmol) 8-oxodG.
Topics: DNA; DNA Adducts; DNA Damage; Microfluidic Analytical Techniques; Oxidation-Reduction
PubMed: 27517117
DOI: 10.1039/c6an01237j -
Carcinogenesis Jun 2022DNA adducts are central in the mechanism of carcinogenesis by genotoxic agents. We compared levels of a DNA adduct of acrolein, a genotoxic carcinogen found in...
DNA adducts are central in the mechanism of carcinogenesis by genotoxic agents. We compared levels of a DNA adduct of acrolein, a genotoxic carcinogen found in e-cigarette vapor, in oral cell DNA of e-cigarette users and non-users of any tobacco or nicotine product. e-Cigarette users and non-users visited our clinic once monthly for 6 months, and oral brushings and urine samples were collected. For this study, we analyzed oral cell DNA adducts from three monthly visits in e-cigarette users and non-users as confirmed by urinary cyanoethyl mercapturic acid and total nicotine equivalents. DNA was isolated from the oral brushings and analyzed by a validated liquid chromatography-nanoelectrospray ionization-high resolution tandem mass spectrometry method for the acrolein DNA adduct 8R/S-3-(2'-deoxyribos-1'-yl)-5,6,7,8-tetrahydro-8-hydroxypyrimido[1,2-a]purine-10-(3H)-one (γ-OH-Acr-dGuo). The median value of this DNA adduct in the e-cigarette users was 179 fmol/µmol dGuo (range 5.0 - 793 fmol/µmol dGuo) while that for non-users was 21.0 fmol/µmol dGuo (range 5.0 - 539 fmol/µmol dGuo), P = 0.001. These results demonstrate for the first time that e-cigarette users have elevated levels of a carcinogen-DNA adduct in their oral cells.
Topics: Acrolein; Carcinogens; Chromatography, High Pressure Liquid; DNA; DNA Adducts; Electronic Nicotine Delivery Systems; Nicotine; Spectrometry, Mass, Electrospray Ionization
PubMed: 35239969
DOI: 10.1093/carcin/bgac026 -
Environmental Health Perspectives Oct 1994In an attempt to elucidate the relationship between DNA adduct formation and tumorigenesis, DNA adducts were measured in the livers and bladders of mice during chronic... (Review)
Review
In an attempt to elucidate the relationship between DNA adduct formation and tumorigenesis, DNA adducts were measured in the livers and bladders of mice during chronic exposure to several different doses of 2-acetylaminofluorene (2-AAF) and 4-aminobiphenyl (4-ABP). Continuous oral administration of these compounds for 4 weeks produced an increase in DNA adduct formation during the first 2 weeks, followed by a plateau, which presumably occurred because the rate of adduct removal offset the rate of adduct formation. The quantity of DNA adducts present at equilibrium correlated directly with the carcinogen concentration; therefore, when exposure was continued for 4 weeks, DNA adducts that reflected the plateau level at each dose could be expressed as a function of dose. Liver and bladder DNA adduct profiles thus obtained during administration of multiple doses of 2-AAF (to female mice) and 4-ABP (to male and female mice) were compared to profiles for tumor incidences obtained during lifetime exposures to the same doses. These experiments demonstrated similar profiles for DNA adduct formation and tumorigenesis in liver. In the bladder, DNA adducts were linear, but tumors only appeared at the higher doses in conjunction with cell proliferation. In addition to these aromatic amines, similar data are available for aflatoxin B1, diethylnitrosamine, and (methylnitrosamino)-1-(3-pyridyl)-1-butanone (also known as nicotine-derived nitrosoketone). Of the nine different biological situations (carcinogen/species/sex/organ) for which data are available, correlations between steady-state DNA adduct levels and tumorigenic response at the different doses were linear in five of the nine biological models.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: 2-Acetylaminofluorene; Aminobiphenyl Compounds; Animals; Carcinogens; DNA Adducts; Female; Incidence; Liver Neoplasms; Male; Mice; Time Factors; Urinary Bladder Neoplasms
PubMed: 7889840
DOI: 10.1289/ehp.94102s6161 -
Mass Spectrometry Reviews Mar 2020Hazardous chemicals in the environment and diet or their electrophilic metabolites can form adducts with genomic DNA, which can lead to mutations and the initiation of... (Review)
Review
Hazardous chemicals in the environment and diet or their electrophilic metabolites can form adducts with genomic DNA, which can lead to mutations and the initiation of cancer. In addition, reactive intermediates can be generated in the body through oxidative stress and damage the genome. The identification and measurement of DNA adducts are required for understanding exposure and the causal role of a genotoxic chemical in cancer risk. Over the past three decades, P-postlabeling, immunoassays, gas chromatography/mass spectrometry, and liquid chromatography/mass spectrometry (LC/MS) methods have been established to assess exposures to chemicals through measurements of DNA adducts. It is now possible to measure some DNA adducts in human biopsy samples, by LC/MS, with as little as several milligrams of tissue. In this review article, we highlight the formation and biological effects of DNA adducts, and highlight our advances in human biomonitoring by mass spectrometric analysis of formalin-fixed paraffin-embedded tissues, untapped biospecimens for carcinogen DNA adduct biomarker research.
Topics: Animals; Biopsy; Chromatography, Liquid; DNA Adducts; Humans; Mass Spectrometry; Mutation; Neoplasms
PubMed: 29889312
DOI: 10.1002/mas.21570