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Tagari EV, Sifnaiou E, Tsolis T, Garoufis A. The Influence of the Auxiliary Ligand in Monofunctional Pt(II) Anticancer Complexes on the DNA Backbone. Int J Mol Sci 2024; 25:6526. [PMID: 38928230 PMCID: PMC11203703 DOI: 10.3390/ijms25126526] [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: 05/13/2024] [Revised: 06/10/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024] Open
Abstract
Monofunctional platinum complexes offer a promising alternative to cisplatin in cancer chemotherapy, showing a unique mechanism of action. Their ability to induce minor helix distortions effectively inhibits DNA transcription. In our study, we synthesized and characterized three monofunctional Pt(II) complexes with the general formula [Pt(en)(L)Cl]NO3, where en = ethylenediamine, and L = pyridine (py), 2-methylpyridine (2-mepy), and 2-phenylpyridine (2-phpy). The hydrolysis rates of [Pt(en)(py)Cl]NO3 (1) and [Pt(en)(2-mepy)Cl]NO3 (2) decrease with the bulkiness of the auxiliary ligand with k(1) = 2.28 ± 0.15 × 10-4 s-1 and k(2) = 8.69 ± 0.98 × 10-5 s-1 at 298 K. The complex [Pt(en)(2-phpy)Cl]Cl (3) demonstrated distinct behavior. Upon hydrolysis, an equilibrium (Keq = 0.385 mM) between the complexes [Pt(en)(2-phpy)Cl]+ and [Pt(en)(2-phpy-H+)]+ was observed with no evidence (NMR or HR-ESI-MS) for the presence of the aquated complex [Pt(en)(2-phpy)(H2O)]2+. Despite the kinetic similarities between phenanthriplatin and (2), complexes (1) and (2) exhibit minimal activity against A549 lung cancer cell line (IC50 > 100 μΜ), whereas complex (3) exhibits notable cytotoxicity (IC50 = 41.11 ± 2.1 μΜ). In examining the DNA binding of (1) and (2) to the DNA model guanosine (guo), we validated their binding through guoN7, which led to an increased population of the C3'-endo sugar conformation, as expected. However, we observed that the rapid transition 2E (C2'-endo) ↔ 3E (C3'-endo), in the case of [Pt(en)(py)(guo)](NO3)2 ([1-guo]), slows down in the case of [Pt(en)(2-mepy)(guo)](NO3)2 ([2-guo]), resulting in separate signals for the two conformers in the 1H NMR spectra. This phenomenon arises from the steric hindrance between the methyl group of pyridine and the sugar moiety of guanosine. Notably, this hindrance is absent in [2-(9-MeG)] (9-MeG = 9-methylguanine), probably due to the absence of a bulky sugar unit in 9-MeG. In the case of (3), where the bulkiness of the substitution on the pyridine is further increased by a phenyl group, we observed a notable proximity between 9-MeGH8 and the phenyl ring of 2-phpy. Considering that only (3) exhibited good cytotoxicity against the A549 cancer cell line, it is suggested that auxiliary ligands, L, with an extended aromatic system and proper orientation in complexes of the type cis-[Pt(en)(L)Cl]NO3, may enhance the cytotoxic activity of such complexes.
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Affiliation(s)
- Evanthia-Vasiliki Tagari
- Laboratory of Inorganic Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece; (E.-V.T.); (E.S.); (T.T.)
| | - Evangelia Sifnaiou
- Laboratory of Inorganic Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece; (E.-V.T.); (E.S.); (T.T.)
| | - Theodoros Tsolis
- Laboratory of Inorganic Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece; (E.-V.T.); (E.S.); (T.T.)
| | - Achilleas Garoufis
- Laboratory of Inorganic Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece; (E.-V.T.); (E.S.); (T.T.)
- Institute of Materials Science and Computing, University Research Centre of Ioannina (URCI), 45110 Ioannina, Greece
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2
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Crisalli AM, Chen YT, Cai A, Li D, Cho BP. Conformation-dependent lesion bypass of bulky arylamine-dG adducts generated from 2-nitrofluorene in epigenetic sequence contexts. Nucleic Acids Res 2023; 51:12043-12053. [PMID: 37953358 PMCID: PMC10711442 DOI: 10.1093/nar/gkad1038] [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] [Received: 08/05/2023] [Revised: 09/27/2023] [Accepted: 10/24/2023] [Indexed: 11/14/2023] Open
Abstract
Sequence context influences structural characteristics and repair of DNA adducts, but there is limited information on how epigenetic modulation affects conformational heterogeneity and bypass of DNA lesions. Lesions derived from the environmental pollutant 2-nitrofluorene have been extensively studied as chemical carcinogenesis models; they adopt a sequence-dependent mix of two significant conformers: major groove binding (B) and base-displaced stacked (S). We report a conformation-dependent bypass of the N-(2'-deoxyguanosin-8-yl)-7-fluoro-2-aminofluorene (dG-FAF) lesion in epigenetic sequence contexts (d[5'-CTTCTC#G*NCCTCATTC-3'], where C# is C or 5-methylcytosine (5mC), G* is G or G-FAF, and N is A, T, C or G). FAF-modified sequences with a 3' flanking pyrimidine were better bypassed when the 5' base was 5mC, whereas sequences with a 3' purine exhibited the opposite effect. The conformational basis behind these variations differed; for -CG*C- and -CG*T-, bypass appeared to be inversely correlated with population of the duplex-destabilizing S conformer. On the other hand, the connection between conformation and a decrease in bypass for flanking purines in the 5mC sequences relative to C was more complex. It could be related to the emergence of a disruptive non-S/B conformation. The present work provides novel conformational insight into how 5mC influences the bypass efficiency of bulky DNA damage.
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Affiliation(s)
- Alicia M Crisalli
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Yi-Tzai Chen
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Ang Cai
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Bongsup P Cho
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
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Sánchez-Meza J, Campos-Valdez M, Domínguez-Rosales JA, Godínez-Rubí JM, Rodríguez-Reyes SC, Martínez-López E, Zúñiga-González GM, Sánchez-Orozco LV. Chronic Administration of Diethylnitrosamine and 2-Acetylaminofluorene Induces Hepatocellular Carcinoma in Wistar Rats. Int J Mol Sci 2023; 24:ijms24098387. [PMID: 37176094 PMCID: PMC10179122 DOI: 10.3390/ijms24098387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/30/2023] [Accepted: 05/05/2023] [Indexed: 05/15/2023] Open
Abstract
This study aimed to analyze the biochemical, histological, and gene expression alterations produced in a hepatocarcinogenesis model induced by the chronic administration of diethylnitrosamine (DEN) and 2-acetylaminofluorene (2-AAF) in Wistar rats. Thirteen rats weighing 180 to 200 g were divided into two groups: control and treated. Rats in the treated group were administered an intraperitoneal (i.p.) injection of DEN (50 mg/kg/week) and an intragastric (i.g.) dose of 2-AAF (25 mg/kg/week) for 18 weeks. The treated group had significant increases in their total cholesterol, HDL-C, AST, ALT, ALKP, and GGT levels. Furthermore, a histological analysis showed the loss of normal liver architecture with nuclear pleomorphism in the hepatocytes, atypical mitosis, and fibrous septa that were distributed between the portal triads and collagen fibers through the hepatic sinusoids. The gene expressions of 24 genes related to fibrosis, inflammation, apoptosis, cell growth, angiogenesis, lipid metabolism, and alpha-fetoprotein (AFP) were analyzed; only TGFβ, COL1α1, CYP2E1, CAT, SOD, IL6, TNF-α, and ALB showed significant differences when both groups were compared. Additionally, lung histopathological alterations were found in the treated group, suggesting metastasis. In this model, the chronic administration of DEN+2-AAF induces characteristic alterations of hepatocellular carcinoma in Wistar rats without AFP gene expression changes, highlighting different signatures in hepatocellular carcinoma heterogeneity.
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Affiliation(s)
- Jaime Sánchez-Meza
- Instituto de Enfermedades Crónico Degenerativas, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Mexico
| | - Marina Campos-Valdez
- Instituto de Enfermedades Crónico Degenerativas, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Mexico
| | - José Alfredo Domínguez-Rosales
- Instituto de Enfermedades Crónico Degenerativas, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Mexico
| | - Juliana Marisol Godínez-Rubí
- Laboratorio de Patología Diagnóstica e Inmunohistoquímica, Departamento de Microbiología y Patología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Mexico
| | - Sarai Citlalic Rodríguez-Reyes
- Instituto de Nutrigenética y Nutrigenómica Traslacional, Centro Universitario de Ciencias de la Salud, Guadalajara 44340, Mexico
| | - Erika Martínez-López
- Instituto de Nutrigenética y Nutrigenómica Traslacional, Centro Universitario de Ciencias de la Salud, Guadalajara 44340, Mexico
| | - Guillermo M Zúñiga-González
- Laboratorio de Mutagénesis, Centro de Investigación Biomédica de Occidente, Instituto Mexicano del Seguro Social, Guadalajara 44340, Mexico
| | - Laura Verónica Sánchez-Orozco
- Instituto de Enfermedades Crónico Degenerativas, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Mexico
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Satoh K, Yamakawa D, Kasai K, Hatayama I. Vibratome technique revealed initial carcinogenic changes that induce GST-P + single hepatocytes and minifoci in rat liver. Anal Biochem 2023; 672:115168. [PMID: 37080414 DOI: 10.1016/j.ab.2023.115168] [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: 02/19/2023] [Revised: 04/16/2023] [Accepted: 04/18/2023] [Indexed: 04/22/2023]
Abstract
The drastic initial carcinogenic changes that induce single hepatocytes and minifoci positive for GST-P (a specific biomarker of foci and nodules) identified previously in rat livers (K. Satoh, Life Sci. 2018) require elucidation. Notably, after animals were administered benzyl isothiocyanate (BITC, anti-cancer phytochemical, 0.5% by wt) in their basal diet, immunocytochemical staining of vibratome-prepared liver specimens for GST-P revealed that the canalicular networks and bile ducts of the animal livers were heavily and finely stained for GST-P even though the biomarker is a cytosolic enzyme. In addition, the mean diameter of the canaliculi was greatly enlarged. The results thus indicate that GST-P was rapidly synthesized in all hepatocytes but rapidly excreted into bile. Similar results were obtained with animals administered dietary AAF carcinogen (0.04%). The biliary excretion of GST-P was detectable not only in all hepatocytes but also within minifoci, foci and nodules. A new initiation model was therefore proposed assuming that GST-P+ single hepatocytes are formed after injury to canaliculi by carcinogens to decrease the excretion of GST-P from hepatocytes. The key findings from this study and the biomarker analysis using a vibratome technique might help elucidate the 'unknowable' mechanism of cancer initiation in rat chemical carcinogenesis.
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Affiliation(s)
- Kimihiko Satoh
- Department of Biomedical Science, Graduate School of Health Sciences, Hirosaki University, Hon-Cho 66-1, Hirosaki, 036-8564, Japan.
| | - Daishi Yamakawa
- Department of Biomedical Science, Graduate School of Health Sciences, Hirosaki University, Hon-Cho 66-1, Hirosaki, 036-8564, Japan; Department of Physiology, Mie University Graduate School of Medicine, Tsu, Mie, 514-8507, Japan
| | - Kousuke Kasai
- Department of Biomedical Science, Graduate School of Health Sciences, Hirosaki University, Hon-Cho 66-1, Hirosaki, 036-8564, Japan
| | - Ichiro Hatayama
- Division of Microbiology, Aomori Prefectural Institute of Public Health and Environment, Aomori Tsukurimichi 1-1-1, Aomori, 030-8566, Japan
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Hájková-Strejcová A, Augustín M, Barek J, Iffelsberger C, Matysik FM, Vyskočil V. New strategy in electrochemical investigation of DNA damage demonstrated on genotoxic derivatives of fluorene. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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6
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Rozelle AL, Lee S. Genotoxic C8-Arylamino-2'-deoxyadenosines Act as Latent Alkylating Agents to Induce DNA Interstrand Cross-Links. J Am Chem Soc 2021; 143:18960-18976. [PMID: 34726902 DOI: 10.1021/jacs.1c07234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
DNA interstrand cross-links (ICLs) are extremely deleterious and structurally diverse, driving the evolution of ICL repair pathways. Discovering ICL-inducing agents is, thus, crucial for the characterization of ICL repair pathways and Fanconi anemia, a genetic disease caused by mutations in ICL repair genes. Although several studies point to oxidative stress as a cause of ICLs, oxidative stress-induced cross-linking events remain poorly characterized. Also, polycyclic aromatic amines, potent environmental carcinogens, have been implicated in producing ICLs, but their identities and sequences are unknown. To close this knowledge gap, we tested whether ICLs arise by the oxidation of 8-arylamino-2'-deoxyadenosine (ArNHdA) lesions, adducts produced by arylamino carcinogens. Herein, we report that ArNHdA acts as a latent cross-linking agent to generate ICLs under oxidative conditions. The formation of an ICL from 8-aminoadenine, but not from 8-aminoguanine, highlights the specificity of 8-aminopurine-mediated ICL production. Under the influence of the reactive oxygen species (ROS) nitrosoperoxycarbonate, ArNHdA (Ar = biphenyl, fluorenyl) lesions were selectively oxidized to generate ICLs. The cross-linking reaction may occur between the C2-ArNHdA and N2-dG, presumably via oxidation of ArNHdA into a reactive diiminoadenine intermediate followed by the nucleophilic attack of the N2-dG on the diiminoadenine. Overall, ArNHdA-mediated ICLs represent rare examples of ROS-induced ICLs and polycyclic aromatic amine-mediated ICLs. These results reveal novel cross-linking chemistry and the genotoxic effects of arylamino carcinogens and support the hypothesis that C8-modified adenines with low redox potential can cause ICLs in oxidative stress.
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Affiliation(s)
- Aaron L Rozelle
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States.,McKetta Department of Chemical Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Seongmin Lee
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States
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7
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Downs TR, Arlt VM, Barnett BC, Posgai R, Pfuhler S. Effect of 2-acetylaminofluorene and its genotoxic metabolites on DNA adduct formation and DNA damage in 3D reconstructed human skin tissue models. Mutagenesis 2021; 36:63-74. [PMID: 31816077 PMCID: PMC8081378 DOI: 10.1093/mutage/gez044] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/15/2019] [Indexed: 12/14/2022] Open
Abstract
In vitro genotoxicity assays utilising human skin models are becoming important tools for the safety assessment of chemicals whose primary exposure is via the dermal route. In order to explore metabolic competency and inducibility of CYP450 activating enzymes, 3D reconstructed human skin tissues were topically treated with 2-acetylaminofluorene (2-AAF) and its genotoxic metabolites, N-hydroxy-2-acetylaminofluorene (N-OH-2-AAF) and N-hydroxy-2-aminofluorene (N-OH-2-AF), which primarily cause DNA damage by forming DNA adducts. 2-AAF did not increase DNA damage measured in the reconstructed skin micronucleus (RSMN) assay when administered in multiple applications at 24 h intervals but was detected in the skin comet assay in the presence of the DNA polymerase inhibitor aphidicolin (APC). Similarly, no increase was found with N-OH-2-AAF in the RSMN assay after multiple treatments whereas a single 3 h exposure to N-OH-2-AAF caused a large dose-related increase in the skin comet assay. A significant increase in the RSMN assay was only obtained with the highly reactive N-OH-2-AF metabolite after multiple treatments over 72 h, whereas N-OH-2-AF caused a strong increase after a single 3 h exposure in the skin comet assay. In support of these results, DNA adduct formation, measured by the 32P-postlabelling assay, was examined. Adduct levels after 2-AAF treatment for 3 h were minimal but increased >10-fold after multiple exposures over 48 h, suggesting that enzyme(s) that metabolise 2-AAF are induced in the skin models. As expected, a single 3 h exposure to N-OH-2-AAF and N-OH-2-AF resulted in adduct levels that were at least 10-fold greater than those after multiple exposures to 2-AAF despite ~100-fold lower tested concentrations. Our results demonstrate that DNA damage caused by 2-AAF metabolites is more efficiently detected in the skin comet assay than the RSMN assay and after multiple exposures and enzyme induction, 2-AAF-induced DNA damage can be detected in the APC-modified comet assay.
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Affiliation(s)
| | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, King’s College London, London, UK
- NIHR Health Protection Research Unit in Health Impact of Environmental Hazards, King’s College London in Partnership with Public Health England and Imperial College London, London, UK
| | | | | | - Stefan Pfuhler
- Procter & Gamble, Mason, OH, USA
- To whom correspondence should be addressed. Tel: +1 513 622 1163; E-mail:
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Kim BW, Lee H, Keum G, Kim BM. Structure-activity relationship (SAR) studies on the mutagenic properties of 2,7-diaminofluorene and 2,7-diaminocarbazole derivatives. Bioorg Med Chem Lett 2020; 31:127662. [PMID: 33227415 DOI: 10.1016/j.bmcl.2020.127662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/20/2020] [Accepted: 10/28/2020] [Indexed: 01/26/2023]
Abstract
We discovered that 2,7-diaminofluorene or 2,7-diaminocarbazole moiety can be employed as a core structure of highly effective NS5A inhibitors that are connected through amide bonds to proline-valine-carbamate motifs. Amide bonds can be easily cleaved via various metabolic pathways upon administration into the body, and metabolites containing 2,7-diaminofluorene and 2,7-diaminocarbazole core structures have been known to be strong mutagens. To avoid the mutagenesis issue of these core structures, we examined various functional groups at the C9 or N9 position of 2,7-diaminofluorene or 2,7-diaminocarbazole, respectively, through the Ames test in TA98 and TA100 mutants of Salmonella typhimurium LT-2. We discovered that, through proper alkyl substitution at the C9 or N9 position, 2,7-diaminofluorene and 2,7-diaminocarbazole moieties can be successfully employed in drug discovery without necessarily causing mutagenicity problems.
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Affiliation(s)
- Byeong Wook Kim
- Department of Chemistry, College of Natural Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Hwa Lee
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Gyochang Keum
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.
| | - B Moon Kim
- Department of Chemistry, College of Natural Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
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Dayanidhi DPE, Thangavel N, Vaidyanathan Ganesan V. Selective Recognition of Conformation-Specific Arylamine–DNA Adduct in Frameshift Model by [Ru(phen)2(dppz)]2+. Chem Res Toxicol 2020; 33:800-805. [DOI: 10.1021/acs.chemrestox.9b00453] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- David Paul Elisa Dayanidhi
- Academy of Scientific and Innovative Research, Advanced Materials Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600 020, India
| | - Nandhini Thangavel
- Academy of Scientific and Innovative Research, Advanced Materials Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600 020, India
| | - Vaidyanathan Vaidyanathan Ganesan
- Academy of Scientific and Innovative Research, Advanced Materials Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600 020, India
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Baldauf KJ, Salazar-González RA, Doll MA, Pierce WM, States JC, Hein DW. Role of Human N-Acetyltransferase 2 Genetic Polymorphism on Aromatic Amine Carcinogen-Induced DNA Damage and Mutagenicity in a Chinese Hamster Ovary Cell Mutation Assay. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:235-245. [PMID: 31490564 PMCID: PMC7017392 DOI: 10.1002/em.22331] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/27/2019] [Accepted: 08/30/2019] [Indexed: 05/10/2023]
Abstract
Carcinogenic aromatic amines such as 4-aminobiphenyl (ABP) and 2-aminofluorene (AF) require metabolic activation to form electrophilic intermediates that mutate DNA leading to carcinogenesis. Bioactivation of these carcinogens includes N-hydroxylation catalyzed by CYP1A2 followed by O-acetylation catalyzed by arylamine N-acetyltransferase 2 (NAT2). To better understand the role of NAT2 genetic polymorphism in ABP- and AF-induced mutagenesis and DNA damage, nucleotide excision repair-deficient (UV5) Chinese hamster ovary (CHO) cells were stably transfected with human CYP1A2 and either NAT2*4 (rapid acetylator) or NAT2*5B (slow acetylator) alleles. ABP and AF both caused significantly (P < 0.001) greater mutagenesis measured at the hypoxanthine phosphoribosyl transferase (hprt) locus in the UV5/CYP1A2/NAT2*4 acetylator cell line compared to the UV5, UV5/CYP1A2, and UV5/CYP1A2/NAT2*5B cell lines. ABP- and AF-induced hprt mutant cDNAs were sequenced and over 80% of the single-base substitutions were at G:C base pairs. DNA damage also was quantified by γH2AX in-cell western assays and by identification and quantification of the two predominant DNA adducts, N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-ABP) and N-(deoxyguanosin-8-yl)-2-aminofluorene (dG-C8-AF) by liquid chromatography-mass spectrometry. DNA damage and adduct levels were dose-dependent, correlated highly with levels of hprt mutants, and were significantly (P < 0.0001) greater in the UV5/CYP1A2/NAT2*4 rapid acetylator cell line following treatment with ABP or AF as compared to all other cell lines. Our findings provide further clarity on the importance of O-acetylation in CHO mutagenesis assays for aromatic amines. They provide evidence that NAT2 genetic polymorphism modifies aromatic amine-induced DNA damage and mutagenesis that should be considered in human risk assessments following aromatic amine exposures. Environ. Mol. Mutagen. 61:235-245, 2020. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
| | | | | | | | | | - David W. Hein
- Correspondence to: David W. Hein, Kosair Charities CTR-Room 303, 505 South Hancock Street, Louisville, Kentucky 40202.
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Junaid M, Wang Y, Hamid N, Deng S, Li WG, Pei DS. Prioritizing selected PPCPs on the basis of environmental and toxicogenetic concerns: A toxicity estimation to confirmation approach. JOURNAL OF HAZARDOUS MATERIALS 2019; 380:120828. [PMID: 31301631 DOI: 10.1016/j.jhazmat.2019.120828] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 04/08/2019] [Accepted: 06/25/2019] [Indexed: 06/10/2023]
Abstract
Pharmaceuticals and personal care products (PPCPs), the pollutants of emerging concerns, present potential risks to the ecological environment. This study focused on the prioritization of widely used selected PPCPs belonging to two categories:personal care products (PCPs) and non-steroidal anti-inflammatory drugs (NSAIDs). We predicted the toxicogenetic endpoints of PPCPs and then confirmed them using experimental approaches. Our results revealed a significant similarity in the findings obtained through both approaches, indicating NSAIDs with relatively high environmental impacts and in vitro/vivo toxicity. Experimental approach revealed that musk xylene (MX) from PCPs and DIC from NSAIDs as individual chemicals of priority concern showed elevated environmental impacts and significantly induced pi3k-akt-mTOR in vitro. Similarly, propyl paraben (PP) from PCPs and diclofenac (DIC) from NSAIDs caused significant cytotoxicity and DNA damage in vitro. Moreover, PP and MX from the PCPs group and naproxen (NAP) and DIC from the NSAIDs group induced developmental toxicity and perturbations to phases I, II, and III detoxification pathways in vivo. In addition, MX and DIC as priority PPCPs inhibited hematopoiesis and hepatogenesis in vivo. Apart from the specific effects, PPCPs can be ranked as: MX > PP > methylparaben (MP) for PCPs, and DIC > NAP > ibuprofen (IBU) for NSAIDs, regarding their toxic and environmental concerns.
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Affiliation(s)
- Muhammad Junaid
- College of Life Science, Henan Normal University, Xinxiang 453007, China; Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Wang
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Naima Hamid
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shun Deng
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Wei-Guo Li
- College of Life Science, Henan Normal University, Xinxiang 453007, China
| | - De-Sheng Pei
- College of Life Science, Henan Normal University, Xinxiang 453007, China; Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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12
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White PA, Luijten M, Mishima M, Cox JA, Hanna JN, Maertens RM, Zwart EP. In vitro mammalian cell mutation assays based on transgenic reporters: A report of the International Workshop on Genotoxicity Testing (IWGT). MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 847:403039. [DOI: 10.1016/j.mrgentox.2019.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/26/2019] [Accepted: 04/06/2019] [Indexed: 02/07/2023]
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13
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Xu D, Huang CH, Xie LN, Shao B, Mao L, Shao J, Kalyanaraman B, Zhu BZ. Mechanism of unprecedented hydroxyl radical production and site-specific oxidative DNA damage by photoactivation of the classic arylhydroxamic acid carcinogens. Carcinogenesis 2019; 40:1153-1163. [PMID: 30870561 DOI: 10.1093/carcin/bgz021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/07/2019] [Accepted: 02/14/2019] [Indexed: 12/17/2023] Open
Abstract
The carcinogenicity of N-hydroxy-2-acetamidofluorene (N-OHAAF), the major genotoxic metabolite of the classic model aromatic amine (AA) carcinogen 2-acetylaminofluorene, has been attributed mainly to the formation of DNA adducts via arylnitrenium upon enzymatic activation. Here, we show, unexpectedly, that exposure of N-OHAAF to UV or sunlight irradiation can not only induce the formation of the well-known covalent DNA adducts, but, more interestingly, simultaneous generation of oxidative DNA damage was also observed as measured by the formation of DNA single-/double-strand breaks (SSBs/DSBs) and 8-oxo-2'-deoxyguanosine (8-oxodG), which were partly inhibited by the typical hydroxyl radical (•OH) scavengers. Electron spin resonance spin-trapping and fluorescent studies unequivocally confirmed that the highly reactive •OH was generated from photolysis of N-OHAAF. Further DNA sequencing investigations suggest that photoactivation of N-OHAAF caused preferential cleavage at guanine, thymine and cytosine sites. More importantly, the formation of 8-oxodG and DSBs were also observed when fibroblast Balb/c-3T3 cells were co-exposed to N-OHAAF/UV irradiation as measured by double immunofluorescence staining. Taken together, we propose that both •OH and amidyl radicals can be readily produced via N-OH homolysis in N-OHAAF by photoirradiation, which can induce both oxidative and covalent DNA damage. This represents the first report of •OH production and site-specific DNA damage via photoactivation of the genotoxic hydroxamic acid intermediate, which provides a new free radical perspective to better understand the molecular mechanism for the carcinogenicity of AAs.
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Affiliation(s)
- Dan Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Chun-Hua Huang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Lin-Na Xie
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Bo Shao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Li Mao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Jie Shao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P. R. China
| | | | - Ben-Zhan Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P. R. China
- Linus Pauling Institute, Oregon State University, Corvallis, OR, USA
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The mutagenic activity of select azo compounds in MutaMouse target tissues in vivo and primary hepatocytes in vitro. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 844:25-34. [DOI: 10.1016/j.mrgentox.2019.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/12/2019] [Accepted: 06/12/2019] [Indexed: 12/13/2022]
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15
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Primary aromatic amines and cancer: Novel mechanistic insights using 4-aminobiphenyl as a model carcinogen. Pharmacol Ther 2019; 200:179-189. [DOI: 10.1016/j.pharmthera.2019.05.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 05/02/2019] [Indexed: 02/07/2023]
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16
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Chakraborty S, Steinbach PJ, Paul D, Mu H, Broyde S, Min JH, Ansari A. Enhanced spontaneous DNA twisting/bending fluctuations unveiled by fluorescence lifetime distributions promote mismatch recognition by the Rad4 nucleotide excision repair complex. Nucleic Acids Res 2019; 46:1240-1255. [PMID: 29267981 PMCID: PMC5815138 DOI: 10.1093/nar/gkx1216] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 12/12/2017] [Indexed: 12/15/2022] Open
Abstract
Rad4/XPC recognizes diverse DNA lesions including ultraviolet-photolesions and carcinogen-DNA adducts, initiating nucleotide excision repair. Studies have suggested that Rad4/XPC senses lesion-induced helix-destabilization to flip out nucleotides from damaged DNA sites. However, characterizing how DNA deformability and/or distortions impact recognition has been challenging. Here, using fluorescence lifetime measurements empowered by a maximum entropy algorithm, we mapped the conformational heterogeneities of artificially destabilized mismatched DNA substrates of varying Rad4-binding specificities. The conformational distributions, as probed by FRET between a cytosine-analog pair exquisitely sensitive to DNA twisting/bending, reveal a direct connection between intrinsic DNA deformability and Rad4 recognition. High-specificity CCC/CCC mismatch, free in solution, sampled a strikingly broad range of conformations from B-DNA-like to highly distorted conformations that resembled those observed with Rad4 bound; the extent of these distortions increased with bound Rad4 and with temperature. Conversely, the non-specific TAT/TAT mismatch had a homogeneous, B-DNA-like conformation. Molecular dynamics simulations also revealed a wide distribution of conformations for CCC/CCC, complementing experimental findings. We propose that intrinsic deformability promotes Rad4 damage recognition, perhaps by stalling a diffusing protein and/or facilitating ‘conformational capture’ of pre-distorted damaged sites. Surprisingly, even mismatched DNA specifically bound to Rad4 remains highly dynamic, a feature that may reflect the versatility of Rad4/XPC to recognize many structurally dissimilar lesions.
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Affiliation(s)
- Sagnik Chakraborty
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Peter J Steinbach
- Center for Molecular Modeling, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Debamita Paul
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Hong Mu
- Department of Biology, New York University, New York, NY 10003, USA
| | - Suse Broyde
- Department of Biology, New York University, New York, NY 10003, USA
| | - Jung-Hyun Min
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Anjum Ansari
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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Cox JA, Zwart EP, Luijten M, White PA. The development and prevalidation of an in vitro mutagenicity assay based on MutaMouse primary hepatocytes, Part I: Isolation, structural, genetic, and biochemical characterization. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:331-347. [PMID: 30592088 PMCID: PMC6590113 DOI: 10.1002/em.22253] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/10/2018] [Accepted: 09/15/2018] [Indexed: 06/09/2023]
Abstract
To develop an improved in vitro mammalian cell gene mutation assay, it is imperative to address the known deficiencies associated with existing assays. Primary hepatocytes isolated from the MutaMouse are ideal for an in vitro gene mutation assay due to their metabolic competence, their "normal" karyotype (i.e., neither transformed nor immortalized), and the presence of the MutaMouse transgene for rapid and reliable mutation scoring. The cells were extensively characterized to confirm their utility. Freshly isolated cells were found to have a hepatocyte-like morphology, predominantly consisting of binucleated cells. These cells maintain hepatocyte-specific markers for up to 3 days in culture. Analyses revealed a normal murine hepatocyte karyotype with a modal ploidy number of 4n. Fluorescence in situ hybridization analysis confirmed the presence of the lambda shuttle vector on chromosome 3. The doubling time was determined to be 22.5 ± 3.3 h. Gene expression and enzymatic activity of key Phase I and Phase II metabolic enzymes were maintained for at least 8 and 24 h in culture, respectively. Exposure to β-naphthoflavone led to approximately 900- and 9-fold increases in Cyp1a1 and Cyp1a2 gene expression, respectively, and approximately twofold induction in cytochrome P450 (CYP) 1A1/1A2 activity. Exposure to phenobarbital resulted in an approximately twofold increase in CYP 2B6 enzyme activity. Following this characterization, it is evident that MutaMouse primary hepatocytes have considerable promise for in vitro mutagenicity assessment. The performance of these cells in an in vitro gene mutation assay is assessed in Part II. Environ. Mol. Mutagen. 60:331-347, 2019. © 2018 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.
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Affiliation(s)
- Julie A. Cox
- Environmental Health Science and Research Bureau, Health CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOntarioCanada
| | - Edwin P. Zwart
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Mirjam Luijten
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Paul A. White
- Environmental Health Science and Research Bureau, Health CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOntarioCanada
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18
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Cox JA, Zwart EP, Luijten M, White PA. The development and prevalidation of an in vitro mutagenicity assay based on MutaMouse primary hepatocytes, Part II: Assay performance for the identification of mutagenic chemicals. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:348-360. [PMID: 30714215 PMCID: PMC6593967 DOI: 10.1002/em.22277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/23/2019] [Accepted: 01/29/2019] [Indexed: 06/09/2023]
Abstract
As demonstrated in Part I, cultured MutaMouse primary hepatocytes (PHs) are suitable cells for use in an in vitro gene mutation assay due to their metabolic competence, their "normal" phenotype, and the presence of the MutaMouse transgene for reliable mutation scoring. The performance of these cells in an in vitro gene mutation assay is evaluated in this study, Part II. A panel of 13 mutagenic and nonmutagenic compounds was selected to investigate the performance of the MutaMouse PH in vitro gene mutation assay. The nine mutagens represent a range of classes of chemicals and include mutagens that are both direct-acting and requiring metabolic activation. All the mutagens tested, except for ICR 191, elicited significant, concentration-dependent increases in mutant frequency (MF) ranging from 2.6- to 14.4-fold over the control. None of the four nonmutagens, including two misleading, or "false," positives (i.e., tertiary butylhydroquinone [TBHQ] and eugenol), yielded any significant increases in MF. The benchmark dose covariate approach facilitated ranking of the positive chemicals from most (i.e., 3-nitrobenzanthrone [3-NBA], benzo[a]pyrene [BaP], and aflatoxin B1 [AFB1]) to least (i.e., N-ethyl-N-nitrosourea [ENU]) potent. Overall, the results of this preliminary validation study suggest that this assay may serve as a complimentary tool alongside the standard genotoxicity test battery. This study, alongside Part I, illustrates the promise of MutaMouse PHs for use in an in vitro gene mutation assay, particularly for chemicals requiring metabolic activation. Environ. Mol. Mutagen. 60:348-360, 2019. © 2019 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.
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Affiliation(s)
- Julie A. Cox
- Environmental Health Science and Research BureauHealth CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
| | - Edwin P. Zwart
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Mirjam Luijten
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Paul A. White
- Environmental Health Science and Research BureauHealth CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
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19
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A comparison of 24 chemicals in the six-well bacterial reverse mutation assay to the standard 100-mm Petri plate bacterial reverse mutation assay in two laboratories. Regul Toxicol Pharmacol 2018; 100:134-160. [DOI: 10.1016/j.yrtph.2018.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 10/04/2018] [Accepted: 10/20/2018] [Indexed: 11/20/2022]
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20
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Abstract
The eukaryotic global genomic nucleotide excision repair (GG-NER) pathway is the major mechanism that removes most bulky and some nonbulky lesions from cellular DNA. There is growing evidence that certain DNA lesions are repaired slowly or are entirely resistant to repair in cells, tissues, and in cell extract model assay systems. It is well established that the eukaryotic DNA lesion-sensing proteins do not detect the damaged nucleotide, but recognize the distortions/destabilizations in the native DNA structure caused by the damaged nucleotides. In this article, the nature of the structural features of certain bulky DNA lesions that render them resistant to NER, or cause them to be repaired slowly, is compared to that of those that are good-to-excellent NER substrates. Understanding the structural features that distinguish NER-resistant DNA lesions from good NER substrates may be useful for interpreting the biological significance of biomarkers of exposure of human populations to genotoxic environmental chemicals. NER-resistant lesions can survive to replication and cause mutations that can initiate cancer and other diseases. Furthermore, NER diminishes the efficacy of certain chemotherapeutic drugs, and the design of more potent pharmaceuticals that resist repair can be advanced through a better understanding of the structural properties of DNA lesions that engender repair-resistance.
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Affiliation(s)
- Nicholas E. Geacintov
- Chemistry and Biology Departments, New York University, New York, New York 10003-5180, United States
| | - Suse Broyde
- Chemistry and Biology Departments, New York University, New York, New York 10003-5180, United States
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21
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Chatterjee N, Walker GC. Mechanisms of DNA damage, repair, and mutagenesis. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2017; 58:235-263. [PMID: 28485537 PMCID: PMC5474181 DOI: 10.1002/em.22087] [Citation(s) in RCA: 997] [Impact Index Per Article: 142.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 03/16/2017] [Indexed: 05/08/2023]
Abstract
Living organisms are continuously exposed to a myriad of DNA damaging agents that can impact health and modulate disease-states. However, robust DNA repair and damage-bypass mechanisms faithfully protect the DNA by either removing or tolerating the damage to ensure an overall survival. Deviations in this fine-tuning are known to destabilize cellular metabolic homeostasis, as exemplified in diverse cancers where disruption or deregulation of DNA repair pathways results in genome instability. Because routinely used biological, physical and chemical agents impact human health, testing their genotoxicity and regulating their use have become important. In this introductory review, we will delineate mechanisms of DNA damage and the counteracting repair/tolerance pathways to provide insights into the molecular basis of genotoxicity in cells that lays the foundation for subsequent articles in this issue. Environ. Mol. Mutagen. 58:235-263, 2017. © 2017 Wiley Periodicals, Inc.
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22
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Ebert C, Simon N, Schneider S, Carell T. Structural Insights into the Recognition of N
2
-Aryl- and C8-Aryl DNA Lesions by the Repair Protein XPA/Rad14. Chembiochem 2017; 18:1379-1382. [DOI: 10.1002/cbic.201700169] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Indexed: 01/28/2023]
Affiliation(s)
- Charlotte Ebert
- Center for Integrated Protein Science at the Department of Chemistry; Ludwig-Maximilians-Universität München; Butenandtstrasse 5-13 81377 München Germany
| | - Nina Simon
- Center for Integrated Protein Science at the Department of Chemistry; Ludwig-Maximilians-Universität München; Butenandtstrasse 5-13 81377 München Germany
| | - Sabine Schneider
- Center for Integrated Protein Science at the Department of Chemistry; Technische Universität München; Lichtenbergstrasse 4 85748 Garching Germany
| | - Thomas Carell
- Center for Integrated Protein Science at the Department of Chemistry; Ludwig-Maximilians-Universität München; Butenandtstrasse 5-13 81377 München Germany
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23
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Gupta P, Gramatke A, Einspanier R, Schütte C, von Kleist M, Sharbati J. In silico cytotoxicity assessment on cultured rat intestinal cells deduced from cellular impedance measurements. Toxicol In Vitro 2017; 41:179-188. [PMID: 28263893 DOI: 10.1016/j.tiv.2017.02.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 02/16/2017] [Accepted: 02/27/2017] [Indexed: 11/16/2022]
Abstract
Early and reliable identification of chemical toxicity is of utmost importance. At the same time, reduction of animal testing is paramount. Therefore, methods that improve the interpretability and usability of in vitro assays are essential. xCELLigence's real-time cell analyzer (RTCA) provides a novel, fast and cost effective in vitro method to probe compound toxicity. We developed a simple mathematical framework for the qualitative and quantitative assessment of toxicity for RTCA measurements. Compound toxicity, in terms of its 50% inhibitory concentration IC50 on cell growth, and parameters related to cell turnover were estimated on cultured IEC-6 cells exposed to 10 chemicals at varying concentrations. Our method estimated IC50 values of 113.05, 7.16, 28.69 and 725.15 μM for the apparently toxic compounds 2-acetylamino-fluorene, aflatoxin B1, benzo-[a]-pyrene and chloramphenicol in the tested cell line, in agreement with literature knowledge. IC50 values of all apparent in vivo non-toxic compounds were estimated to be non-toxic by our method. Corresponding estimates from RTCA's in-built model gave false positive (toxicity) predictions in 5/10 cases. Taken together, our proposed method reduces false positive predictions and reliably identifies chemical toxicity based on impedance measurements. The source code for the developed method including instructions is available at https://git.zib.de/bzfgupta/toxfit/tree/master.
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Affiliation(s)
- P Gupta
- Department of Mathematics and Informatics, Freie Universität Berlin, Arnimallee 6, Berlin 14195, Germany; Department of Mathematics for Life and Materials Sciences, Zuse Institute Berlin, Takustrasse 7, Berlin 14195, Germany.
| | - A Gramatke
- Department of Veterinary Biochemistry, Freie Universität Berlin, Oertzenweg 19b, Building 12, Berlin 14163, Germany.
| | - R Einspanier
- Department of Veterinary Biochemistry, Freie Universität Berlin, Oertzenweg 19b, Building 12, Berlin 14163, Germany.
| | - C Schütte
- Department of Mathematics and Informatics, Freie Universität Berlin, Arnimallee 6, Berlin 14195, Germany; Department of Mathematics for Life and Materials Sciences, Zuse Institute Berlin, Takustrasse 7, Berlin 14195, Germany.
| | - M von Kleist
- Department of Mathematics and Informatics, Freie Universität Berlin, Arnimallee 6, Berlin 14195, Germany.
| | - J Sharbati
- Department of Veterinary Biochemistry, Freie Universität Berlin, Oertzenweg 19b, Building 12, Berlin 14163, Germany.
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Kumar M, Kaur P, Chandel M, Singh AP, Jain A, Kaur S. Antioxidant and hepatoprotective potential of Lawsonia inermis L. leaves against 2-acetylaminofluorene induced hepatic damage in male Wistar rats. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 17:56. [PMID: 28100199 PMCID: PMC5242058 DOI: 10.1186/s12906-017-1567-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 01/07/2017] [Indexed: 01/08/2023]
Abstract
Background Lawsonia inermis (Lythraceae) is an ethnomedicinal plant, traditionally known for curing several ailments such as skin diseases, bacterial infections, jaundice, renal lithiases and inflammation etc. The present work deals with assessment of in vitro antioxidant and in vivo hepatoprotective potential of butanolic fraction (But-LI) of Lawsonia inermis L. leaves. Methods Antioxidant activity was evaluated using deoxyribose degradation, lipid peroxidation inhibition and ferric reducing antioxidant power (FRAP) assay. In vivo protective potential of But-LI was assessed at 3 doses [100, 200 & 400 mg/kg body weight (bw)] against 2-acetylaminofluorene (2-AAF) induced hepatic damage in male Wistar rats. Results But-LI effectively scavenged hydroxyl radicals in deoxyribose degradation assay (IC50 149.12 μg/ml). Fraction also inhibited lipid peroxidation and demonstrated appreciable reducing potential in FRAP assay. Treatment of animals with 2-AAF resulted in increased hepatic parameters such as SGOT (2.22 fold), SGPT (1.72 fold), ALP (5.68 fold) and lipid peroxidation (2.94 fold). Different concentration of But-LI demonstrated pronounced protective effects via decreasing levels of SGOT, SGPT, ALP and lipid peroxidation altered by 2-AAF treatment. But-LI administration also restored the normal liver architecture as evident from histopathological studies. Conclusions The present experimental findings revealed that phytoconstituents of Lawsonia inermis L. possess potential to effectively protect rats from the 2-AAF induced hepatic damage in vivo possibly by inhibition of reactive oxygen species and lipid peroxidation.
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Seidel SD, Stott WT, Kan HL, Sparrow BR, Gollapudi BB. Gene Expression Dose-Response of Liver with a Genotoxic and Nongenotoxic Carcinogen. Int J Toxicol 2016; 25:57-64. [PMID: 16510358 DOI: 10.1080/10915810500488429] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Tumorigenic mechanisms due to chemical exposure are broadly classified as either genotoxic or nongenotoxic. Genotoxic mechanisms are generally well defined; however nongenotoxic modes of tumorgenesis are less straightforward. This study was undertaken to help elucidate dose-response changes in gene expression (transcriptome) in the liver of rats in response to administration of known genotoxic or nongenotoxic liver carcinogens. Male Big Blue Fischer 344 rats were treated for 28-days with 0, 0.1, 0.3, 1.0, or 3.0 mg/kg/day of the genotoxin 2-acetylaminofluorene (AAF) or 0, 10, 30, 60, or 100 mg/kg/day of the nongenotoxin phenobarbital (PB). Transcriptome analysis was performed using the relatively focused Clontech Rat Toxicology II microarray (465 genes) and hybridized with 32P-labeled cDNA target. The analysis indicated that after 28 days of treatment, AAF altered the expression of 14 genes (9 up-and 5 down-regulated) and PB altered the expression of 18 genes (10 up- and 8 down-regulated). Of the limited genes whose expression was altered by AAF and PB, four were altered in common, two up-regulated, and two down-regulated. Several of the genes that show modulation of transcriptional activity following AAF and PB treatment display an atypical dose-response relationship such that the expression at the higher doses tended to be similar to that of control. This high-dose effect could potentially be caused by adaptation, toxicity, or tissue remodeling. These results suggest that the transcriptional response of the cells to higher doses of a toxic agent is likely to be different from that of a low-dose exposure.
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Affiliation(s)
- Shawn D Seidel
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan 48674, USA.
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26
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Shigano M, Ishii N, Takashima R, Harada H, Takasawa H, Hamada S. Results of rat Pig-a/PIGRET assay with a single dose regimen of 1,3-propane sultone and 2-acetyl aminofluorene. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2016; 811:75-79. [DOI: 10.1016/j.mrgentox.2016.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 04/01/2016] [Indexed: 10/22/2022]
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27
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Song B, Shen M, Jiang D, Malla S, Mosa IM, Choudhary D, Rusling JF. Microfluidic array for simultaneous detection of DNA oxidation and DNA-adduct damage. Analyst 2016; 141:5722-5729. [PMID: 27517117 PMCID: PMC5048564 DOI: 10.1039/c6an01237j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
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 (E2), its metabolites 4-hydroxyestradiol (4-OHE2), 2-hydroxyestradiol (2-OHE2), 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 106 bases. Each sensor requires only 22 ng of DNA, so the mass detection limit is 15 pg (∼10 pmol) 8-oxodG.
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Affiliation(s)
- Boya Song
- Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA.
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Dissociation Dynamics of XPC-RAD23B from Damaged DNA Is a Determining Factor of NER Efficiency. PLoS One 2016; 11:e0157784. [PMID: 27327897 PMCID: PMC4915676 DOI: 10.1371/journal.pone.0157784] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/03/2016] [Indexed: 12/18/2022] Open
Abstract
XPC-RAD23B (XPC) plays a critical role in human nucleotide excision repair (hNER) as this complex recognizes DNA adducts to initiate NER. To determine the mutagenic potential of structurally different bulky DNA damages, various studies have been conducted to define the correlation of XPC-DNA damage equilibrium binding affinity with NER efficiency. However, little is known about the effects of XPC-DNA damage recognition kinetics on hNER. Although association of XPC is important, our current work shows that the XPC-DNA dissociation rate also plays a pivotal role in achieving NER efficiency. We characterized for the first time the binding of XPC to mono- versus di-AAF-modified sequences by using the real time monitoring surface plasmon resonance technique. Strikingly, the half-life (t1/2 or the retention time of XPC in association with damaged DNA) shares an inverse relationship with NER efficiency. This is particularly true when XPC remained bound to clustered adducts for a much longer period of time as compared to mono-adducts. Our results suggest that XPC dissociation from the damage site could become a rate-limiting step in NER of certain types of DNA adducts, leading to repression of NER.
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Soeteman-Hernández LG, Fellows MD, Johnson GE, Slob W. Correlation of In Vivo Versus In Vitro Benchmark Doses (BMDs) Derived From Micronucleus Test Data: A Proof of Concept Study. Toxicol Sci 2015; 148:355-67. [PMID: 26443842 PMCID: PMC4659532 DOI: 10.1093/toxsci/kfv189] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In this study, we explored the applicability of using in vitro micronucleus (MN) data from human lymphoblastoid TK6 cells to derive in vivo genotoxicity potency information. Nineteen chemicals covering a broad spectrum of genotoxic modes of action were tested in an in vitro MN test using TK6 cells using the same study protocol. Several of these chemicals were considered to need metabolic activation, and these were administered in the presence of S9. The Benchmark dose (BMD) approach was applied using the dose-response modeling program PROAST to estimate the genotoxic potency from the in vitro data. The resulting in vitro BMDs were compared with previously derived BMDs from in vivo MN and carcinogenicity studies. A proportional correlation was observed between the BMDs from the in vitro MN and the BMDs from the in vivo MN assays. Further, a clear correlation was found between the BMDs from in vitro MN and the associated BMDs for malignant tumors. Although these results are based on only 19 compounds, they show that genotoxicity potencies estimated from in vitro tests may result in useful information regarding in vivo genotoxic potency, as well as expected cancer potency. Extension of the number of compounds and further investigation of metabolic activation (S9) and of other toxicokinetic factors would be needed to validate our initial conclusions. However, this initial work suggests that this approach could be used for in vitro to in vivo extrapolations which would support the reduction of animals used in research (3Rs: replacement, reduction, and refinement).
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Affiliation(s)
| | - Mick D Fellows
- AstraZeneca, R&D Alderley Park, Macclesfield, Cheshire SK10 4TF, United Kingdom; and
| | - George E Johnson
- Institute of Life Science, Swansea University Medical School, Swansea University, SA2 8PP Wales, United Kingdom
| | - Wout Slob
- *National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
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Kraynak A, Barnum J, Cunningham C, Ng A, Ykoruk B, Bennet B, Stoffregen D, Merschman M, Freeland E, Galloway S. Alkaline comet assay in liver and stomach, and micronucleus assay in bone marrow, from rats treated with 2-acetylaminofluorene, azidothymidine, cisplatin, or isobutyraldehyde. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015. [DOI: 10.1016/j.mrgentox.2015.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Stavros KM, Hawkins EK, Rizzo CJ, Stone MP. Base-Displaced Intercalated Conformation of the 2-Amino-3-methylimidazo[4,5-f]quinoline N(2)-dG DNA Adduct Positioned at the Nonreiterated G(1) in the NarI Restriction Site. Chem Res Toxicol 2015; 28:1455-68. [PMID: 26083477 PMCID: PMC4511292 DOI: 10.1021/acs.chemrestox.5b00140] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
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The
conformation of an N2-dG adduct
arising from the heterocyclic amine 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), a potent food mutagen, was determined
in 5′-d(C1T2C3X4G5C6G7C8C9A10T11C12)-3′:5′-d(G13A14T15G16G17C18G19C20C21G22A23G24)-3′; X = N2-dG-IQ, in which the modified nucleotide X4 corresponds to G1 in the 5′-d(G1G2CG3CC)-3′ NarI restriction endonuclease site. Circular dichroism (CD) revealed
blue shifts relative to the unmodified duplex, consistent with adduct-induced
twisting, and a hypochromic effect for the IQ absorbance in the near
UV region. NMR revealed that the N2-dG-IQ
adduct adopted a base-displaced intercalated conformation in which
the modified guanine remained in the anti conformation
about the glycosidic bond, the IQ moiety intercalated into the duplex,
and the complementary base C21 was displaced into the major
groove. The processing of the N2-dG-IQ
lesion by hpol η is sequence-dependent; when placed at the reiterated
G3 position, but not at the G1 position, this
lesion exhibits a propensity for frameshift replication [Choi, J.
Y., et al. (2006) J. Biol. Chem., 281, 25297–25306]. The structure of the N2-dG-IQ adduct at the nonreiterated G1 position
was compared to that of the same adduct placed at the G3 position [Stavros, K. M., et al. (2014) Nucleic Acids Res., 42, 3450–3463]. CD indicted minimal spectral
differences between the G1 vs G3N2-dG-IQ adducts. NMR indicated that the N2-dG-IQ adduct exhibited similar base-displaced intercalated
conformations at both the G1 and G3 positions.
This result differed as compared to the corresponding C8-dG-IQ adducts
placed at the same positions. The C8-dG-IQ adduct adopted a minor
groove conformation when placed at position G1 but a base-displaced
intercalated conformation when placed at position G3 in
the NarI sequence. The present studies suggest that
differences in lesion bypass by hpol η may be mediated by differences
in the 3′-flanking sequences, perhaps modulating the ability
to accommodate transient strand slippage intermediates.
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Affiliation(s)
- Kallie M Stavros
- †Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235-1822, United States
| | | | - Carmelo J Rizzo
- †Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235-1822, United States
| | - Michael P Stone
- †Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235-1822, United States
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Sedlačková E, Bábelová A, Kozics K, Šelc M, Srančíková A, Frecer V, Gábelová A. Ultraviolet A radiation potentiates the cytotoxic and genotoxic effects of 7 H-dibenzo[c,g]carbazole and its methyl derivatives. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2015; 56:388-403. [PMID: 25421724 DOI: 10.1002/em.21927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 11/05/2014] [Indexed: 06/04/2023]
Abstract
7H-Dibenzo[c,g]carbazole (DBC) is a heterocyclic aromatic hydrocarbon that is carcinogenic in many species and tissues. DBC is a common environmental pollutant, and is therefore constantly exposed to sunlight. However, there are limited data exploring the toxicity of DBC photoexcitation products. Here, we investigated the impact of ultraviolet (UV) A radiation on the biological activity of DBC and its methyl derivatives, 5,9-dibenzo[c,g]carbazole and N-methyl dibenzo[c,g]carbazole, on human skin HaCaT keratinocytes. Co-exposure of HaCaT cells to UVA and DBC derivatives resulted in a sharp dose-dependent decrease in cell survival and apparent changes in cell morphology. Under the same treatment conditions, significant increases in DNA strand breaks, intracellular reactive oxygen species, and oxidative damage to DNA were observed in HaCaT cells. Consistent with these results, an apparent inhibition in superoxide dismutase, but not glutathione peroxidase activity, was detected in cells treated with DBC and its derivatives under UVA irradiation. The photoactivation-induced toxicity of individual DBC derivatives correlated with the electron excitation energies approximately expressed as the energy difference between the highest occupied and the lowest vacant molecular orbital. Our data provide the first evidence that UVA can enhance the toxicity of DBC and its derivatives. Photoactivation-induced conversion of harmless chemical compounds to toxic photoproducts associated with reactive oxygen species generation may substantially amplify the adverse health effects of UVA radiation and contribute to increased incidence of skin cancer.
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Affiliation(s)
- Eva Sedlačková
- Laboratory of Mutagenesis and Carcinogenesis, Cancer Research Institute, SAS, Vlarska 7, Bratislava, Slovakia
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Takashima R, Takasawa H, Kawasako K, Ohyama W, Okada E, Narumi K, Fujiishi Y, Wako Y, Yasunaga K, Hattori A, Kawabata M, Nakadate K, Nakagawa M, Hamada S. Evaluation of a repeated dose liver micronucleus assay in rats treated with two genotoxic hepatocarcinogens, dimethylnitrosamine and 2-acetylaminofluorene: The possibility of integrating micronucleus tests with multiple tissues into a repeated dose general toxicity study. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 780-781:18-24. [DOI: 10.1016/j.mrgentox.2014.10.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 11/26/2022]
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Wasalathanthri DP, Li D, Song D, Zheng Z, Choudhary D, Jansson I, Lu X, Schenkman JB, Rusling JF. Elucidating Organ-Specific Metabolic Toxicity Chemistry from Electrochemiluminescent Enzyme/DNA Arrays and Bioreactor Bead-LC-MS/MS. Chem Sci 2015; 6:2457-2468. [PMID: 25798217 PMCID: PMC4364445 DOI: 10.1039/c4sc03401e] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Combining electrochemiluminescent array and bioreactor bead-LC-MS/MS featuring metabolic enzyme-DNA films provide an efficient, comprehensive approach to simultaneously elucidate metabolic DNA damage chemistries at different human organs for potential new drugs.
Human toxic responses are very often related to metabolism. Liver metabolism is traditionally studied, but other organs also convert chemicals and drugs to reactive metabolites leading to toxicity. When DNA damage is found, the effects are termed genotoxic. Here we describe a comprehensive new approach to evaluate chemical genotoxicity pathways from metabolites formed in situ by a broad spectrum of liver, lung, kidney and intestinal enzymes. DNA damage rates are measured with a microfluidic array featuring a 64-nanowell chip to facilitate fabrication of films of DNA, electrochemiluminescent (ECL) detection polymer [Ru(bpy)2(PVP)10]2+ {(PVP = poly(4-vinylpyridine))} and metabolic enzymes. First, multiple enzyme reactions are run on test compounds using the array, then ECL light related to the resulting DNA damage is measured. A companion method next facilitates reaction of target compounds with DNA/enzyme-coated magnetic beads in 96 well plates, after which DNA is hydrolyzed and nucleobase-metabolite adducts are detected by LC-MS/MS. The same organ enzymes are used as in the arrays. Outcomes revealed nucleobase adducts from DNA damage, enzymes responsible for reactive metabolites (e.g. cyt P450s), influence of bioconjugation, relative dynamics of enzymes suites from different organs, and pathways of possible genotoxic chemistry. Correlations between DNA damage rates from the cell-free array and organ-specific cell-based DNA damage were found. Results illustrate the power of the combined DNA/enzyme microarray/LC-MS/MS approach to efficiently explore a broad spectrum of organ-specific metabolic genotoxic pathways for drugs and environmental chemicals.
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Affiliation(s)
- Dhanuka P Wasalathanthri
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States National University of Ireland at Galway, Ireland
| | - Dandan Li
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States National University of Ireland at Galway, Ireland
| | - Donghui Song
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Zhifang Zheng
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States National University of Ireland at Galway, Ireland
| | - Dharamainder Choudhary
- Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut 06032, United States
| | - Ingela Jansson
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut 06032, United States
| | - Xiuling Lu
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269, United States
| | - John B Schenkman
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut 06032, United States
| | - James F Rusling
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States National University of Ireland at Galway, Ireland ; Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut 06032, United States
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Monente C, Bravo J, Vitas AI, Arbillaga L, De Peña MP, Cid C. Coffee and spent coffee extracts protect against cell mutagens and inhibit growth of food-borne pathogen microorganisms. J Funct Foods 2015. [DOI: 10.1016/j.jff.2014.12.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Hájková A, Barek J, Vyskočil V. Voltammetric Determination of 2-Aminofluoren-9-one and Investigation of Its Interaction with DNA on a Glassy Carbon Electrode. ELECTROANAL 2014. [DOI: 10.1002/elan.201400427] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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37
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Hasan SK, Khan R, Ali N, Khan AQ, Rehman MU, Tahir M, Lateef A, Nafees S, Mehdi SJ, Rashid S, Shahid A, Sultana S. 18-β Glycyrrhetinic acid alleviates 2-acetylaminofluorene-induced hepatotoxicity in Wistar rats. Hum Exp Toxicol 2014; 34:628-41. [DOI: 10.1177/0960327114554045] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
2-Acetylaminofluorene (2-AAF) is a known hepatic carcinogen which leads to tumour formation in rodents. 18-β Glycyrrhetinic acid (18 β-GA) derived from liquorice plant has various pharmacological properties such as anti-ulcer, anti-inflammatory, antiviral, hepatoprotective and antioxidant. This study is designed to elucidate the chemopreventive properties of 18 β-GA against 2-AAF-induced liver toxicity in Wistar rats and evaluated its effect on inflammatory and tumour promotion marker and activities of different oxidative stress enzymes. Administration of 2-AAF at the dose of (50 mg/kg body weight (b.w.) intraperitoneally (i.p.)) for five consecutive days induces hepatic toxicity, inflammation, oxidative stress and hyperproliferation. Pretreatment with 18 β-GA at two different doses (45 and 75 mg kg−1 b.w.) significantly ameliorates 2-AAF-induced increased lipid peroxidation, alanine transaminase and aspartate transaminase, xanthine oxidase activities and activities of phase-II detoxifying enzymes along with the levels of glutathione content. Administration of 18 β-GA also significantly restored the expressions of proliferating cell nuclear antigen, cyclooxygenase 2, inducible nitric oxide synthase and nuclear factor κB. Furthermore, histological observations also support the preventive effects of 18 β-GA. Our findings suggest that pretreatment with 18 β-GA showed potential hepatoprotective effects via attenuation of oxidative stress, inflammation and hyperproliferation.
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Affiliation(s)
- SK Hasan
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - R Khan
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - N Ali
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - AQ Khan
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - MU Rehman
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - M Tahir
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - A Lateef
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - S Nafees
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - SJ Mehdi
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - S Rashid
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - A Shahid
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
| | - S Sultana
- Section of Molecular Carcinogenesis and Chemoprevention, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, India
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Jain V, Vaidyanathan VG, Patnaik S, Gopal S, Cho BP. Conformational insights into the lesion and sequence effects for arylamine-induced translesion DNA synthesis: 19F NMR, surface plasmon resonance, and primer kinetic studies. Biochemistry 2014; 53:4059-71. [PMID: 24915610 PMCID: PMC4075988 DOI: 10.1021/bi5003212] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
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Adduct-induced DNA damage can affect
transcription efficiency and
DNA replication and repair. We previously investigated the effects
of the 3′-next flanking base (G*CT vs G*CA; G*, FABP, N-(2′-deoxyguanosin-8-yl)-4′-fluoro-4-aminobiphenyl;
FAF, N-(2′-deoxyguanosin-8-yl)-7-fluoro-2-aminofluorene)
on the conformation of arylamine-DNA lesions in relation to E. coli nucleotide excision repair (JainV., HiltonB., LinB., PatnaikS., LiangF., DarianE., ZouY., MackerellA. D.Jr., and ChoB. P. (2013) Nucleic Acids Res., 41, 869−88023180767). Here,
we report the differential effects of the same pair of sequences on
DNA replication in vitro by the polymerases exofree
Klenow fragment (Kf-exo–) and Dpo4. We obtained
dynamic 19F NMR spectra for two 19-mer modified templates
during primer elongation: G*CA [d(5′-CTTACCATCG*CAACCATTC-3′)]
and G*CT [d(5′-CTTACCATCG*CTACCATTC-3′)].
We found that lesion stacking is favored in the G*CT sequence compared to the G*CA counterpart. Surface
plasmon resonance binding results showed consistently weaker affinities
for the modified DNA with the binding strength in the order of FABP
> FAF and G*CA > G*CT. Primer extension was stalled at
(n) and near (n – 1 and n + 1) the lesion site, and the extent of blockage and the extension
rates across the lesion were influenced by not only the DNA sequences
but also the nature of the adduct’s chemical structure (FAF
vs FABP) and the polymerase employed (Kf-exo– vs
Dpo4). Steady-state kinetics analysis with Kf-exo– revealed the most dramatic sequence and lesion effects at the lesion
(n) and postinsertion (n + 1) sites,
respectively. Taken together, these results provide insights into
the important role of lesion-induced conformational heterogeneity
in modulating translesion DNA synthesis.
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Affiliation(s)
- Vipin Jain
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
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Orlov S, Goncharova I, Urbanová M. Circular dichroism study of the interaction between mutagens and bilirubin bound to different binding sites of serum albumins. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 126:68-75. [PMID: 24589992 DOI: 10.1016/j.saa.2014.01.139] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/26/2014] [Accepted: 01/28/2014] [Indexed: 06/03/2023]
Abstract
Although recent investigations have shown that bilirubin not only has a negative role in the organism but also exhibits significant antimutagenic properties, the mechanisms of interactions between bilirubin and mutagens are not clear. In this study, interaction between bilirubin bound to different binding sites of mammalian serum albumins with structural analogues of the mutagens 2-aminofluorene, 2,7-diaminofluorene and mutagen 2,4,7-trinitrofluorenone were investigated by circular dichroism and absorption spectroscopy. Homological human and bovine serum albumins were used as chiral matrices, which preferentially bind different conformers of bilirubin in the primary binding sites and make it observable by circular dichroism. These molecular systems approximated a real system for the study of mutagens in blood serum. Differences between the interaction of bilirubin bound to primary and to secondary binding sites of serum albumins with mutagens were shown. For bilirubin bound to secondary binding sites with low affinity, partial displacement and the formation of self-associates were observed in all studied mutagens. The associates of bilirubin bound to primary binding sites of serum albumins are formed with 2-aminofluorene and 2,4,7-trinitrofluorenone. It was proposed that 2,7-diaminofluorene does not interact with bilirubin bound to primary sites of human and bovine serum albumins due to the spatial hindrance of the albumins binding domains. The spatial arrangement of the bilirubin bound to serum albumin along with the studied mutagens was modelled using ligand docking, which revealed a possibility of an arrangement of the both bilirubin and 2-aminofluorene and 2,4,7-trinitrofluorenone in the primary binding site of human serum albumin.
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Affiliation(s)
- Sergey Orlov
- Department of Analytical Chemistry, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic.
| | - Iryna Goncharova
- Department of Analytical Chemistry, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic.
| | - Marie Urbanová
- Department of Physics and Measurements, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic.
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Stavros KM, Hawkins EK, Rizzo CJ, Stone MP. Base-displaced intercalation of the 2-amino-3-methylimidazo[4,5-f]quinolone N2-dG adduct in the NarI DNA recognition sequence. Nucleic Acids Res 2014; 42:3450-63. [PMID: 24366876 PMCID: PMC3950664 DOI: 10.1093/nar/gkt1109] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 10/18/2013] [Accepted: 10/21/2013] [Indexed: 12/14/2022] Open
Abstract
2-Amino-3-methylimidazo[4,5-f]quinolone (IQ), a heterocyclic amine found in cooked meats, undergoes bioactivation to a nitrenium ion, which alkylates guanines at both the C8-dG and N2-dG positions. The conformation of a site-specific N2-dG-IQ adduct in an oligodeoxynucleotide duplex containing the iterated CG repeat restriction site of the NarI endonuclease has been determined. The IQ moiety intercalates, with the IQ H4a and CH3 protons facing the minor groove, and the IQ H7a, H8a and H9a protons facing the major groove. The adducted dG maintains the anti-conformation about the glycosyl bond. The complementary dC is extruded into the major groove. The duplex maintains its thermal stability, which is attributed to stacking between the IQ moiety and the 5'- and 3'-neighboring base pairs. This conformation is compared to that of the C8-dG-IQ adduct in the same sequence, which also formed a 'base-displaced intercalated' conformation. However, the C8-dG-IQ adopted the syn conformation placing the Watson-Crick edge of the modified dG into the major groove. In addition, the C8-dG-IQ adduct was oriented with the IQ CH3 group and H4a and H5a facing the major groove. These differences may lead to differential processing during DNA repair and replication.
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Affiliation(s)
| | | | | | - Michael P. Stone
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235-1822, USA
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Jain V, Hilton B, Lin B, Jain A, MacKerell AD, Zou Y, Cho BP. Structural and thermodynamic insight into Escherichia coli UvrABC-mediated incision of cluster diacetylaminofluorene adducts on the NarI sequence. Chem Res Toxicol 2013; 26:1251-62. [PMID: 23841451 DOI: 10.1021/tx400186v] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cluster DNA damage refers to two or more lesions in a single turn of the DNA helix. Such clustering may occur with bulky DNA lesions, which may be responsible for their sequence-dependent repair and mutational outcomes. Here we prepared three 16-mer cluster duplexes in which two fluoroacetylaminofluorene adducts (dG-FAAF) are separated by zero, one, and two nucleotides in the Escherichia coli NarI mutational hot spot (5'-CTCTCG1G2CG3CCATCAC-3'): 5'-CG1*G2*CG3CC-3', 5'-CG1G2*CG3*CC-3', and 5'-CG1*G2CG3*CC-3' (G* = dG-FAAF), respectively. We conducted spectroscopic, thermodynamic, and molecular dynamics studies of these di-FAAF duplexes, and the results were compared with those of the corresponding mono-FAAF adducts in the same NarI sequence [Jain, V., et al. (2012) Nucleic Acids Res. 40, 3939-3951]. Our nucleotide excision repair results showed the diadducts were more reparable than the corresponding monoadducts. Moreover, we observed dramatic flanking base sequence effects on their repair efficiency in the following order: NarI-G2G3 > NarI-G1G3 > NarI-G1G2. The nuclear magnetic resonance, circular dichroism, ultraviolet melting, and molecular dynamics simulation results revealed that in contrast to the monoadducts, diadducts produced a synergistic effect on duplex destabilization. In addition, dG-FAAF at G2G3 and G1G3 destacks the neighboring bases, with greater destabilization occurring with the former. Overall, the results indicate the importance of base stacking and related thermal and thermodynamic destabilization in the repair of bulky cluster arylamine DNA adducts.
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Affiliation(s)
- Vipin Jain
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, USA
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Sandineni A, Lin B, MacKerell AD, Cho BP. Structure and thermodynamic insights on acetylaminofluorene-modified deletion DNA duplexes as models for frameshift mutagenesis. Chem Res Toxicol 2013; 26:937-51. [PMID: 23688347 DOI: 10.1021/tx400116n] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
2-Acetylaminofluorene (AAF) is a prototype arylamine carcinogen that forms C8-substituted dG-AAF and dG-AF as the major DNA lesions. The bulky N-acetylated dG-AAF lesion can induce various frameshift mutations depending on the base sequence around the lesion. We hypothesized that the thermodynamic stability of bulged-out slipped mutagenic intermediates (SMIs) is directly related to deletion mutations. The objective of the present study was to probe the structural/conformational basis of various dG-AAF-induced SMIs formed during translesion synthesis. We performed spectroscopic, thermodynamic, and molecular dynamics studies of several AAF-modified 16-mer model DNA duplexes, including fully paired and -1, -2, and -3 deletion duplexes of the 5'-CTCTCGATG[FAAF]CCATCAC-3' sequence and an additional -1 deletion duplex of the 5'-CTCTCGGCG[FAAF]CCATCAC-3' NarI sequence. Modified deletion duplexes existed in a mixture of external B and stacked S conformers, with the population of the S conformer being 'GC'-1 (73%) > 'AT'-1 (72%) > full (60%) > -2 (55%) > -3 (37%). Thermodynamic stability was in the order of -1 deletion > -2 deletion > fully paired > -3 deletion duplexes. These results indicate that the stacked S-type conformer of SMIs is thermodynamically more stable than the conformationally flexible external B conformer. Results from the molecular dynamics simulations indicate that perturbation of base stacking dominates the relative stability along with contributions from bending, duplex dynamics, and solvation effects that are important in specific cases. Taken together, these results support a hypothesis that the conformational and thermodynamic stabilities of the SMIs are critical determinants for the induction of frameshift mutations.
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Affiliation(s)
- Anusha Sandineni
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, USA
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Wang K, Guengerich FP. Reduction of aromatic and heterocyclic aromatic N-hydroxylamines by human cytochrome P450 2S1. Chem Res Toxicol 2013; 26:993-1004. [PMID: 23682735 DOI: 10.1021/tx400139p] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Many aromatic amines and heterocyclic aromatic amines (HAAs) are known carcinogens for animals, and there is also strong evidence of some in human cancer. The activation of these compounds, including some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 enzymes (P450) in Family 1 (1A2, 1A1, and 1B1). We previously demonstrated that the bioactivation product of the anticancer agent 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203), an N-hydroxylamine, can be reduced by P450 2S1 to its amine precursor under anaerobic conditions and, to a lesser extent, under aerobic conditions [Wang, K., and Guengerich, F. P. (2012) Chem. Res. Toxicol. 25, 1740-1751]. In the study presented here, we tested the hypothesis that P450 2S1 is involved in the reductive biotransformation of known carcinogenic aromatic amines and HAAs. The N-hydroxylamines of 4-aminobiphenyl (4-ABP), 2-naphthylamine (2-NA), and 2-aminofluorene (2-AF) were synthesized and found to be reduced by P450 2S1 under both anaerobic and aerobic conditions. The formation of amines due to P450 2S1 reduction also occurred under aerobic conditions but was less apparent because the competitive disproportionation reactions (of the N-hydroxylamines) also yielded amines. Further, some nitroso and nitro derivatives of the arylamines could also be reduced by P450 2S1. None of the amines tested were oxidized by P450 2S1. These results suggest that P450 2S1 may be involved in the reductive detoxication of several of the activated products of carcinogenic aromatic amines and HAAs.
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Affiliation(s)
- Kai Wang
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University, School of Medicine, 638 Robinson Research Building, 2200 Pierce Avenue, Nashville, Tennessee 37232-0146, USA
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Matsushita K, Kijima A, Ishii Y, Takasu S, Jin M, Kuroda K, Kawaguchi H, Miyoshi N, Nohmi T, Ogawa K, Umemura T. Development of a Medium-term Animal Model Using gpt Delta Rats to Evaluate Chemical Carcinogenicity and Genotoxicity. J Toxicol Pathol 2013; 26:19-27. [PMID: 23723564 PMCID: PMC3620210 DOI: 10.1293/tox.26.19] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 11/06/2012] [Indexed: 12/19/2022] Open
Abstract
In this study, the potential for development of an animal model (GPG46) capable of rapidly detecting chemical carcinogenicity and the underlying mechanisms of action were examined in gpt delta rats using a reporter gene assay to detect mutations and a medium-term rat liver bioassay to detect tumor promotion. The tentative protocol for the GPG46 model was developed based on the results of dose-response exposure to diethylnitrosamine (DEN) and treatment with phenobarbital over time following DEN administration. Briefly, gpt delta rats were exposed to various chemicals for 4 weeks, followed by a partial hepatectomy (PH) to collect samples for an in vivo mutation assay. The mutant frequencies (MFs) of the reporter genes were examined as an indication of tumor initiation. A single intraperitoneal (ip) injection of 10 mg/kg DEN was administered to rats 18 h after the PH to initiate hepatocytes. Tumor-promoting activity was evaluated based on the development of glutathione S-transferase placental form (GST-P)-positive foci at week 10. The genotoxic carcinogens 2-acetylaminofluorene (2-AAF), 2-amino-3-methylimidazo [4,5-f] quinolone (IQ) and safrole (SF), the non-genotoxic carcinogens piperonyl butoxide (PBO) and phenytoin (PHE), the non-carcinogen acetaminophen (APAP) and the genotoxic non-hepatocarcinogen aristolochic acid (AA) were tested to validate the GPG46 model. The validation results indicate that the GPG46 model could be a powerful tool in understanding chemical carcinogenesis and provide valuable information regarding human risk hazards.
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Affiliation(s)
- Kohei Matsushita
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
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Krüger S, Meier C. Synthesis of Site-Specific Damaged DNA Strands by 8-(Acetylarylamino)-2′-deoxyguanosine Adducts and Effects on Various DNA Polymerases. European J Org Chem 2013. [DOI: 10.1002/ejoc.201200984] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Mu H, Kropachev K, Wang L, Zhang L, Kolbanovskiy A, Kolbanovskiy M, Geacintov NE, Broyde S. Nucleotide excision repair of 2-acetylaminofluorene- and 2-aminofluorene-(C8)-guanine adducts: molecular dynamics simulations elucidate how lesion structure and base sequence context impact repair efficiencies. Nucleic Acids Res 2012; 40:9675-90. [PMID: 22904073 PMCID: PMC3479214 DOI: 10.1093/nar/gks788] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nucleotide excision repair (NER) efficiencies of DNA lesions can vary by orders of magnitude, for reasons that remain unclear. An example is the pair of N-(2′-deoxyguanosin-8-yl)-2-aminofluorene (dG-C8-AF) and N-(2′-deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-C8-AAF) adducts that differ by a single acetyl group. The NER efficiencies in human HeLa cell extracts of these lesions are significantly different when placed at G1, G2 or G3 in the duplex sequence (5′-CTCG1G2CG3CCATC-3′) containing the NarI mutational hot spot. Furthermore, the dG-C8-AAF adduct is a better substrate of NER than dG-C8-AF in all three NarI sequence contexts. The conformations of each of these adducts were investigated by Molecular dynamics (MD) simulation methods. In the base-displaced conformational family, the greater repair susceptibility of dG-C8-AAF in all sequences stems from steric hindrance effects of the acetyl group which significantly diminish the adduct-base stabilizing van der Waals stacking interactions relative to the dG-C8-AF case. Base sequence context effects for each adduct are caused by differences in helix untwisting and minor groove opening that are derived from the differences in stacking patterns. Overall, the greater NER efficiencies are correlated with greater extents of base sequence-dependent local untwisting and minor groove opening together with weaker stacking interactions.
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Affiliation(s)
- Hong Mu
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
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Vaidyanathan VG, Cho BP. Sequence Effects on Translesion Synthesis of an Aminofluorene–DNA Adduct: Conformational, Thermodynamic, and Primer Extension Kinetic Studies. Biochemistry 2012; 51:1983-95. [DOI: 10.1021/bi2017443] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- V. G. Vaidyanathan
- Department of Biomedical and Pharmaceutical
Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Bongsup P. Cho
- Department of Biomedical and Pharmaceutical
Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, United States
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Jain V, Hilton B, Patnaik S, Zou Y, Chiarelli MP, Cho BP. Conformational and thermodynamic properties modulate the nucleotide excision repair of 2-aminofluorene and 2-acetylaminofluorene dG adducts in the NarI sequence. Nucleic Acids Res 2012; 40:3939-51. [PMID: 22241773 PMCID: PMC3351159 DOI: 10.1093/nar/gkr1307] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Nucleotide excision repair (NER) is a major repair pathway that recognizes and corrects various lesions in cellular DNA. We hypothesize that damage recognition is an initial step in NER that senses conformational anomalies in the DNA caused by lesions. We prepared three DNA duplexes containing the carcinogen adduct N-(2'-deoxyguanosin-8-yl)-7-fluoro-2-acetylaminofluorene (FAAF) at G(1), G(2) or G(3) of NarI sequence (5'-CCG(1)G(2)CG(3)CC-3'). Our (19)F-NMR/ICD results showed that FAAF at G(1) and G(3) prefer syn S- and W-conformers, whereas anti B-conformer was predominant for G(2). We found that the repair of FAAF occurs in a conformation-specific manner, i.e. the highly S/W-conformeric G(3) and -G(1) duplexes incised more efficiently than the B-type G(2) duplex (G(3)∼G(1)> G(2)). The melting and thermodynamic data indicate that the S- and W-conformers produce greater DNA distortion and thermodynamic destabilization. The N-deacetylated N-(2'-deoxyguanosin-8-yl)-7-fluoro-2-aminofluorene (FAF) adducts in the same NarI sequence are repaired 2- to 3-fold less than FAAF: however, the incision efficiency was in order of G(2)∼G(1)> G(3), a reverse trend of the FAAF case. We have envisioned the so-called N-acetyl factor as it could raise conformational barriers of FAAF versus FAF. The present results provide valuable conformational insight into the sequence-dependent UvrABC incisions of the bulky aminofluorene DNA adducts.
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Affiliation(s)
- Vipin Jain
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA
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Baris O, Karadayi M, Yanmis D, Guvenalp Z, Bal T, Gulluce M. Isolation of 3 Flavonoids from Mentha longifolia (L.) Hudson subsp. longifolia and Determination of Their Genotoxic Potentials by Using the E. coli WP2 Test System. J Food Sci 2011; 76:T212-7. [DOI: 10.1111/j.1750-3841.2011.02405.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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