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Pehlivan ÖC, Cavuşoğlu K, Yalçin E, Acar A. In silico interactions and deep neural network modeling for toxicity profile of methyl methanesulfonate. Environ Sci Pollut Res Int 2023; 30:117952-117969. [PMID: 37874518 DOI: 10.1007/s11356-023-30465-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 10/10/2023] [Indexed: 10/25/2023]
Abstract
In this study, the toxicity induced by the alkylating agent methyl methanesulfonate (MMS) in Allium cepa L. was investigated. For this aim, bulbs were divided into 4 groups as control and application (100, 500 and 4000 µM MMS) and germinated for 72 h at 22-24 °C. At the end of the germination period root tips were collected and made ready for analysis by applying traditional preparation methods. Germination, root elongation, weight, mitotic index (MI) values, micronucleus (MN) and chromosomal abnormality (CAs) numbers, malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase (CAT) activities and anatomical structures of bulbs were used as indicators to determine toxicity. Moreover the extent of DNA fragmentation induced by MMS was determined by comet assay. To confirm the DNA fragmentation induced by MMS, the DNA-MMS interaction was examined with molecular docking. Correlation and principal component analyses (PCA) were performed to examine the relationship between all parameters and understand the underlying structure and relationships among these parameters. In the present study, a deep neural network (DNN) with two hidden layers implemented in Matlab has been developed for the comparison of the estimated data with the real data. The effect of MDA levels, SOD and CAT activities at 4 different endpoints resulting from administration of various concentrations of MMS, including MN, MI, CAs and DNA damage, was attempted to be estimated by DNN model. It is assumed that the predicted results are in close agreement with the actual data. The effectiveness of the model was evaluated using 4 different metrics, MAE, MAPE, RMSE and R2, which together show that the model performs commendably. As a result, the highest germination, root elongation, weight gain and MI were measured in the control group. MMS application caused a decrease in all physiological parameters and an increase in cytogenetic (except MI) and biochemical parameters. MMS application caused an increase in antioxidant enzyme levels (SOD and CAT) up to a concentration of 500 µM and a decrease at 4000 µM. MMS application induced different types of CAs and anatomical damages in root meristem cells. The results of the comet assay showed that the severity of DNA fragmentation increased with increasing MMS concentration. Molecular docking analysis showed a strong DNA-MMS interaction. The results of correlation and PCA revealed significant positive and negative interactions between the studied parameters and confirmed the interactions of these parameters with MMS. It has been shown that the DNN model developed in this study is a valuable resource for predicting genotoxicity due to oxidative stress and lipid peroxidation. In addition, this model has the potential to help evaluate the genotoxicity status of various chemical compounds. At the end of the study, it was concluded that MMS strongly supports a versatile toxicity in plant cells and the selected parameters are suitable indicators for determining this toxicity.
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Affiliation(s)
- Ömer Can Pehlivan
- Department of Biology, Institute of Science, Giresun University, Giresun, Türkiye
| | - Kültiğin Cavuşoğlu
- Department of Biology, Faculty of Science and Art, Giresun University, Giresun, Türkiye.
| | - Emine Yalçin
- Department of Biology, Faculty of Science and Art, Giresun University, Giresun, Türkiye
| | - Ali Acar
- Department of Medical Services and Techniques, Vocational School of Health Services, Giresun University, Giresun, Türkiye
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Sugaya N, Tanaka S, Keyamura K, Noda S, Akanuma G, Hishida T. N-terminal acetyltransferase NatB regulates Rad51-dependent repair of double-strand breaks in Saccharomyces cerevisiae. Genes Genet Syst 2023; 98:61-72. [PMID: 37331807 DOI: 10.1266/ggs.23-00013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2023] Open
Abstract
Homologous recombination (HR) is a highly accurate mechanism for repairing DNA double-strand breaks (DSBs) that arise from various genotoxic insults and blocked replication forks. Defects in HR and unscheduled HR can interfere with other cellular processes such as DNA replication and chromosome segregation, leading to genome instability and cell death. Therefore, the HR process has to be tightly controlled. Protein N-terminal acetylation is one of the most common modifications in eukaryotic organisms. Studies in budding yeast implicate a role for NatB acetyltransferase in HR repair, but precisely how this modification regulates HR repair and genome integrity is unknown. In this study, we show that cells lacking NatB, a dimeric complex composed of Nat3 and Mdm2, are sensitive to the DNA alkylating agent methyl methanesulfonate (MMS), and that overexpression of Rad51 suppresses the MMS sensitivity of nat3Δ cells. Nat3-deficient cells have increased levels of Rad52-yellow fluorescent protein foci and fail to repair DSBs after release from MMS exposure. We also found that Nat3 is required for HR-dependent gene conversion and gene targeting. Importantly, we observed that nat3Δ mutation partially suppressed MMS sensitivity in srs2Δ cells and the synthetic sickness of srs2Δ sgs1Δ cells. Altogether, our results indicate that NatB functions upstream of Srs2 to activate the Rad51-dependent HR pathway for DSB repair.
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Affiliation(s)
- Natsuki Sugaya
- Department of Molecular Biology, Graduate School of Science, Gakushuin University
| | - Shion Tanaka
- Department of Molecular Biology, Graduate School of Science, Gakushuin University
| | - Kenji Keyamura
- Department of Molecular Biology, Graduate School of Science, Gakushuin University
| | - Shunsuke Noda
- Department of Molecular Biology, Graduate School of Science, Gakushuin University
| | - Genki Akanuma
- Department of Molecular Biology, Graduate School of Science, Gakushuin University
| | - Takashi Hishida
- Department of Molecular Biology, Graduate School of Science, Gakushuin University
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Damiani AP, Magenis ML, Dagostin LS, Beretta ÂCDL, Sarter RJ, Longaretti LM, Monteiro IDO, Andrade VMD. Royal jelly reduce DNA damage induced by alkylating agent in mice. Mutat Res 2022; 825:111796. [PMID: 36007462 DOI: 10.1016/j.mrfmmm.2022.111796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 08/13/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Royal jelly (RJ) is a creamy white-yellow liquid that is secreted by the mandibular and hypopharyngeal glands of bees to nourish the larvae. RJ has gained increasing interest in recent years owing to its antioxidant potential. However, little is known about adequate RJ dosing and its effects on genetic material. Thus, the aim of this study was to evaluate the in vivo effects of RJ on genotoxicity and mutagenicity induced by the alkylating agent methyl methanesulfonate (MMS). In this study, 3-month-old Swiss albino male mice (N = 66) were divided into 11 groups for experimentation. Experiments were performed by administering lyophilized RJ (150 mg/kg, 300 mg/kg, and 1000 mg/kg) or water via gavage as pre- and posttreatment processes with the alkylating agent MMS. After treatment, blood samples were collected from the mice via an incision at the end of the tail to conduct comet assays at times of 24 h and 48 h posttreatment. The mice were then euthanized to remove the bone marrow for a micronucleus test. Overall, regardless of dose, RJ did not exhibit genotoxic, mutagenic activity and the administration of high doses, mainly in the form of posttreatment, presented antigenotoxic and antimutagenic actions. Further, a dose-response correlation was observed in the RJ posttreatment groups. These results demonstrate that RJ administration was effective in reversing the damage caused by the alkylating agent MMS.
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Affiliation(s)
- Adriani Paganini Damiani
- Laboratory of Translational Biomedicine, Graduate Program of Health Sciences, University of Southern Santa Catarina - UNESC, Criciúma, SC, Brazil
| | - Marina Lummertz Magenis
- Laboratory of Translational Biomedicine, Graduate Program of Health Sciences, University of Southern Santa Catarina - UNESC, Criciúma, SC, Brazil
| | - Ligia Salvan Dagostin
- Laboratory of Translational Biomedicine, Graduate Program of Health Sciences, University of Southern Santa Catarina - UNESC, Criciúma, SC, Brazil
| | - Ângela Caroline da Luz Beretta
- Laboratory of Translational Biomedicine, Graduate Program of Health Sciences, University of Southern Santa Catarina - UNESC, Criciúma, SC, Brazil
| | - Rovena Jacobsen Sarter
- Laboratory of Translational Biomedicine, Graduate Program of Health Sciences, University of Southern Santa Catarina - UNESC, Criciúma, SC, Brazil
| | - Luiza Martins Longaretti
- Laboratory of Translational Biomedicine, Graduate Program of Health Sciences, University of Southern Santa Catarina - UNESC, Criciúma, SC, Brazil
| | - Isadora de Oliveira Monteiro
- Laboratory of Translational Biomedicine, Graduate Program of Health Sciences, University of Southern Santa Catarina - UNESC, Criciúma, SC, Brazil
| | - Vanessa Moraes de Andrade
- Laboratory of Translational Biomedicine, Graduate Program of Health Sciences, University of Southern Santa Catarina - UNESC, Criciúma, SC, Brazil.
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Mitchell C, Becker V, DeLoach J, Nestore E, Bolterstein E, Kohl KP. The Drosophila Mutagen-Sensitivity Gene mus109 Encodes DmDNA2. Genes (Basel) 2022; 13:genes13020312. [PMID: 35205357 PMCID: PMC8872385 DOI: 10.3390/genes13020312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 02/02/2022] [Accepted: 02/04/2022] [Indexed: 02/05/2023] Open
Abstract
The identification of mutants through forward genetic screens is the backbone of Drosophila genetics research, yet many mutants identified through these screens have yet to be mapped to the Drosophila genome. This is especially true of mutants that have been identified as mutagen-sensitive (mus), but have not yet been mapped to their associated molecular locus. Our study addressed the need for additional mus gene identification by determining the locus and exploring the function of the X-linked mutagen-sensitive gene mus109 using three available mutant alleles: mus109D1, mus109D2, and mus109lS. After first confirming that all three mus109 alleles were sensitive to methyl methanesulfonate (MMS) using complementation analysis, we used deletion mapping to narrow the candidate genes for mus109. Through DNA sequencing, we were able to determine that mus109 is the uncharacterized gene CG2990, which encodes the Drosophila ortholog of the highly conserved DNA2 protein that is important for DNA replication and repair. We further used the sequence and structure of DNA2 to predict the impact of the mus109 allele mutations on the final gene product. Together, these results provide a tool for researchers to further investigate the role of DNA2 in DNA repair processes in Drosophila.
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Affiliation(s)
- Chandani Mitchell
- Biology Department, Winthrop University, Rock Hill, SC 29733, USA; (C.M.); (J.D.); (E.N.)
| | - Vada Becker
- Biology Department, Northeastern Illinois University, Chicago, IL 60625, USA; (V.B.); (E.B.)
| | - Jordan DeLoach
- Biology Department, Winthrop University, Rock Hill, SC 29733, USA; (C.M.); (J.D.); (E.N.)
| | - Erica Nestore
- Biology Department, Winthrop University, Rock Hill, SC 29733, USA; (C.M.); (J.D.); (E.N.)
| | - Elyse Bolterstein
- Biology Department, Northeastern Illinois University, Chicago, IL 60625, USA; (V.B.); (E.B.)
| | - Kathryn P. Kohl
- Biology Department, Winthrop University, Rock Hill, SC 29733, USA; (C.M.); (J.D.); (E.N.)
- Correspondence:
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Abstract
The comet assay is widely used in basic research, genotoxicity testing, and human biomonitoring. However, interpretation of the comet assay data might benefit from a better understanding of the future fate of a cell with DNA damage. DNA damage is in principle repairable, or if extensive, can lead to cell death. Here, we have correlated the maximally induced DNA damage with three test substances in TK6 cells with the survival of the cells. For this, we selected hydrogen peroxide (H2O2) as an oxidizing agent, methyl methanesulfonate (MMS) as an alkylating agent and etoposide as a topoisomerase II inhibitor. We measured cell viability, cell proliferation, apoptosis, and micronucleus frequency on the following day, in the same cell culture, which had been analyzed in the comet assay. After treatment, a concentration dependent increase in DNA damage and in the percentage of non-vital and apoptotic cells was found for each substance. Values greater than 20-30% DNA in tail caused the death of more than 50% of the cells, with etoposide causing slightly more cell death than H2O2 or MMS. Despite that, cells seemed to repair of at least some DNA damage within few hours after substance removal. Overall, the reduction of DNA damage over time is due to both DNA repair and death of heavily damaged cells. We recommend that in experiments with induction of DNA damage of more than 20% DNA in tail, survival data for the cells are provided.
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Affiliation(s)
- Ezgi Eyluel Bankoglu
- Institute of Pharmacology and Toxicology, University of Wuerzburg, Versbacher Straße 9, 97078, Wuerzburg, Germany
| | - Carolin Schuele
- Institute of Pharmacology and Toxicology, University of Wuerzburg, Versbacher Straße 9, 97078, Wuerzburg, Germany
| | - Helga Stopper
- Institute of Pharmacology and Toxicology, University of Wuerzburg, Versbacher Straße 9, 97078, Wuerzburg, Germany.
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Ozelin SD, Senedese JM, Alves JM, Munari CC, Costa JDCD, Resende FA, Campos DL, Lima IMDS, Andrade AF, Varanda EA, Bastos JK, Tavares DC. Preventive activity of Copaifera langsdorffii Desf. leaves extract and its major compounds, afzelin and quercitrin, on DNA damage in in vitro and in vivo models. J Toxicol Environ Health A 2021; 84:569-581. [PMID: 33730993 DOI: 10.1080/15287394.2021.1898505] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Copaifera langsdorffii Desf. is a plant found in South America, especially in Brazil. Oleoresin and the leaves of this plant is used as a popular medicinal agent. However, few studies on the chemical composition of aerial parts and related biological activities are known. This study aimed to examine the cytotoxic, genotoxic, and antigenotoxic potential of C. langsdorffii aerial parts hydroalcoholic extract (CLE) and two of its major compounds afzelin and quercitrin. The cytotoxic and antigenotoxic potential of CLE was determined as follows: 1) against genotoxicity induced by doxorubicin (DXR) or methyl methanesulfonate (MMS) in V79 cells; 2) by direct and indirect-acting mutagens in Salmonella typhimurium strains; and 3) by MMS in male Swiss mice. The protective effects of afzelin and quercitrin against DXR or MMS were also evaluated in V79 and HepG2 cells. CLE was cytotoxic as evidenced by clonogenic efficiency assay. Further, CLE did not induce a significant change in frequencies of chromosomal aberrations and micronuclei; as well as number of revertants in the Ames test demonstrating absence of genotoxicity. In contrast, CLE was found to be antigenotoxic in mammalian cells. The results also showed that CLE exerted inhibitory effect against indirect-acting mutagens in the Ames test. Afzelin and quercitrin did not reduce genotoxicity induced by DXR or MMS in V79 cells. However, treatments using afzelin and quercitrin decreased MMS-induced genotoxicity in HepG2 cells. The antigenotoxic effect of CLE observed in this study may be partially attributed to the antioxidant activity of the combination of major components afzelin and quercitrin.
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Affiliation(s)
- Saulo Duarte Ozelin
- Laboratório De Mutagênese, Universidade De Franca, Franca, São Paulo, Brazil
| | | | | | | | | | - Flávia Aparecida Resende
- Faculdade De Ciências Farmacêuticas De Araraquara, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil
| | - Débora Leite Campos
- Faculdade De Ciências Farmacêuticas De Araraquara, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil
| | | | | | - Eliana Aparecida Varanda
- Faculdade De Ciências Farmacêuticas De Araraquara, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil
| | - Jairo Kenupp Bastos
- Facudade De Ciências Farmacêuticas De Ribeirão Preto, Universidade De São Paulo, São Paulo, Brazil
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Liu X, Chen G, Lu GY, Yao J, Zhu FY, Xu J, Li XM. Dual Fluorescent Protein (yEGFP/DsRed-Express-2) Bioassay System for Rapid Screening for Chemical Mutagens Based on RNR3 Regulation in Saccharomyces Cerevisiae. Biomed Environ Sci 2021; 34:421-424. [PMID: 34059182 DOI: 10.3967/bes2021.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Affiliation(s)
- Xing Liu
- Preventive Medicine Department of Yangzhou Medical College, Yangzhou University, Yangzhou 225001, Jiangsu, China;Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, Jiangsu, China
| | - Geng Chen
- Institute of Toxicology and Risk Assessment, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210009, Jiangsu, China
| | - Gang Yu Lu
- Preventive Medicine Department of Yangzhou Medical College, Yangzhou University, Yangzhou 225001, Jiangsu, China
| | - Jia Yao
- Preventive Medicine Department of Yangzhou Medical College, Yangzhou University, Yangzhou 225001, Jiangsu, China
| | - Fang Yu Zhu
- Preventive Medicine Department of Yangzhou Medical College, Yangzhou University, Yangzhou 225001, Jiangsu, China
| | - Jun Xu
- Institute of Toxicology and Risk Assessment, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210009, Jiangsu, China
| | - Xiang Ming Li
- Preventive Medicine Department of Yangzhou Medical College, Yangzhou University, Yangzhou 225001, Jiangsu, China;Jiangsu Key Laboratory of Experimental and Translational Non-coding RNA Research, Yangzhou 225001, Jiangsu, China
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Pigarev SE, Trashkov AP, Panchenko AV, Yurova MN, Bykov VN, Fedoros EI, Anisimov VN. Evaluation of the genotoxic and antigenotoxic potential of lignin-derivative BP-C2 in the comet assay in vivo. Environ Res 2021; 192:110321. [PMID: 33075358 DOI: 10.1016/j.envres.2020.110321] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 09/29/2020] [Accepted: 10/06/2020] [Indexed: 06/11/2023]
Abstract
The genotoxic and antigenotoxic potential of BP-C2, a novel lignin-derived polyphenolic composition with ammonium molybdate, was investigated as a radioprotector/radiomitigator for civil applications and as a medical countermeasure for radiation emergencies. Using the alkaline comet assay and methyl methanesulfonate (MMS, 40 mg/kg) as the DNA-damaging agent, these effects of BP-C2 on liver, bone marrow cells and blood leukocytes in rats were studied. The DNA damage was estimated by the DNA content in the comet tail (TDNA, %) 1, 6 and 18 h post exposure to MMS. BP-C2 at doses of 20, 200 and 2000 mg/kg did not exert genotoxic activity in the tested tissues in rats. BP-C2 administered at doses of 20, 100 and 200 mg/kg 1 h before MMS significantly (p < 0.01) mitigated MMS-induced DNA damage, showing a strong genoprotective effect in the liver. In blood leukocytes and bone marrow samples of animals treated with BP-C2, the TDNA % was slightly higher than in the negative control (vehicle) but significantly lower than in the positive control (MMS). Thus, BP-C2 exerted a genoprotective effect against MMS-induced DNA damage to a greater extent towards liver cells, requiring further evaluation of this substance as a genoprotective agent.
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Affiliation(s)
- S E Pigarev
- N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg, Russia; Nobel LTD, Saint-Petersburg, Russia.
| | - A P Trashkov
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of NRC "Kurchatov Institute", Gatchina, Russia
| | - A V Panchenko
- N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg, Russia; FSBSI "Research Institute of Medical Primatology", Sochi, Russian
| | - M N Yurova
- N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg, Russia
| | - V N Bykov
- N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg, Russia
| | - E I Fedoros
- N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg, Russia; Nobel LTD, Saint-Petersburg, Russia
| | - V N Anisimov
- N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg, Russia
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Abstract
Methyl methanesulphonate (MMS) is a DNA damaging agent, which induces oxidative stress, ATP depletion, and consequently, cell death, in HL-60 and K562 cells. The cell death induced by MMS predominantly exhibited the morphological and biochemical hallmarks of necrosis. A minor population of dying cells exhibited apoptotic hallmarks, especially in K562 cell cultures. Cyclosporin A (CsA) was used to modulate the MMS-induced cell death. Our results indicated that CsA did not prevent cells from dying, but changed the mode of death from necrotic to apoptotic. Surprisingly, CsA enhanced oxidative stress and increased the overall number of dead cells. Based on these results, we conclude that the modulatory effect of CsA on MMS-induced cell death might arise from an interference by CsA with mitochondrial metabolism, rather than from inhibition of the MMS efflux mediated by P-glycoprotein.
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Affiliation(s)
- Petr Mlejnek
- Department of Biology, Faculty of Medicine, Palacky University, Olomouc, Czech Republic.
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Perdry H, Gutzkow KB, Chevalier M, Huc L, Brunborg G, Boutet-Robinet E. Validation of Gelbond® high-throughput alkaline and Fpg-modified comet assay using a linear mixed model. Environ Mol Mutagen 2018; 59:595-602. [PMID: 30091211 DOI: 10.1002/em.22204] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/11/2018] [Accepted: 04/20/2018] [Indexed: 06/08/2023]
Abstract
Even if the comet assay has been widely used for decades, there is still a need for controlled studies and good mathematical models to assess the variability of the different versions of this assay and in particular to assess potential intra-experimental variability of the high-throughput comet assay. To address this point, we further validate a high-throughput comet assay that uses hydrophilic polyester film (Gelbond®). Experiments were performed using human peripheral blood mononuclear cells (PBMC) either untreated or treated with different concentration of MMS (methyl methanesulfonate). A positive control for the Fpg (Formamidopyrimidine DNA glycosylase)-modified comet assay (Ro 19-8022 with light) was also included. To quantify the sources of variability of the assay, including intradeposit variability, instead of summarizing DNA damage on 50 cells from a deposit by the mean or median of their percentage DNA tail, we analyzed all logit-transformed data with a linear mixed model. The main source of variation in our experimental data is between cells within the same deposit, suggesting genuine variability in the response of the cells rather than variation caused by technical treatment of cell samples. The second source of variation is the inter-experimental variation (day-to-day experiment); the coefficient of this variation for the control was 13.6%. The variation between deposits in the same experiment is negligible. Moreover, there is no systematic bias because of the position of samples on the Gelbond® film nor the position of the films in the electrophoresis tank. This high-throughput comet assay is thus reliable for various applications. Environ. Mol. Mutagen. 59:595-602, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Hervé Perdry
- Univ Paris-Saclay & INSERM CESP, Villejuif, France
| | - Kristine B Gutzkow
- Department of Molecular Biology, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radioactivity (CoE CERAD), Oslo, Norway
| | - Marianne Chevalier
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Laurence Huc
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Gunnar Brunborg
- Department of Molecular Biology, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radioactivity (CoE CERAD), Oslo, Norway
| | - Elisa Boutet-Robinet
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
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Hamilton ME, Bols NC, Duncker BP. The characterization of γH2AX and p53 as biomarkers of genotoxic stress in a rainbow trout (Oncorhynchus mykiss) brain cell line. Chemosphere 2018; 201:850-858. [PMID: 29554631 DOI: 10.1016/j.chemosphere.2018.03.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/15/2018] [Accepted: 03/03/2018] [Indexed: 06/08/2023]
Abstract
Rainbow trout cell cultures were exposed to three genotoxicants and examined for effects on γH2AX and p53 levels by western blotting and on cell viability using the indicator dyes Alamar Blue (AB) for energy metabolism and 5'-carboxyfluorescein diacetate acetoxymethyl ester (CFDA-AM) for plasma membrane integrity. Bleomycin induced γH2AX and p53 in a dose- and time-dependent manner and had little cytotoxic effect. However, induction was first seen at 0.3 μM for γH2AX but not until 16.5 μM for p53. Methyl methanesulfonate (MMS) increased H2AX phosphorylation but diminished p53 levels as the dose was increased from 908 μM up to 2724 μM. Over this dose range cell viability was progressively lost. 4-nitroquinoline N-oxide (NQO) induced both γH2AX and p53, beginning at 62.5 nM, which was also the concentration at which cell viability began to decline. As the NQO concentration increased further, elevated γH2AX was detected at up to 2.0 μM, while p53 was elevated up to 1.0 μM. Therefore, H2AX phosphorylation was superior to p53 levels as a marker of DNA damage caused by genotoxicants that act by introducing double-stranded DNA breaks (bleomycin), alkyl groups (MMS), and quinoline adducts (NQO).
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Affiliation(s)
- Mark E Hamilton
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Niels C Bols
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Bernard P Duncker
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
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Kim C, Yang J, Jeong SH, Kim H, Park GH, Shin HB, Ro M, Kim KY, Park Y, Kim KP, Kwack K. Yeast-based assays for characterization of the functional effects of single nucleotide polymorphisms in human DNA repair genes. PLoS One 2018; 13:e0193823. [PMID: 29522548 PMCID: PMC5844570 DOI: 10.1371/journal.pone.0193823] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 02/20/2018] [Indexed: 01/03/2023] Open
Abstract
DNA repair mechanisms maintain genomic integrity upon exposure to various types of DNA damage, which cause either single- or double-strand breaks in the DNA. Here, we propose a strategy for the functional study of single nucleotide polymorphisms (SNPs) in the human DNA repair genes XPD/ERCC2, RAD18, and KU70/XRCC6 and the checkpoint activation gene ATR that are essentially involved in the cell cycle and DNA damage repair. We analyzed the mutational effects of the DNA repair genes under DNA-damaging conditions, including ultraviolet irradiation and treatment with genotoxic reagents, using a Saccharomyces cerevisiae system to overcome the limitations of the human cell-based assay. We identified causal variants from selected SNPs in the present analyses. (i) R594C SNP in RAD3 (human XPD/ERCC2) caused severe reductions in the growth rate of mutant cells upon short-wavelength UV irradiation or chemical reagent treatment. (ii) The growth rates of the selected variants in RAD18, YKU70, and MEC1 were similar to those of wild-type cells on methyl methanesulfonate and hydroxyurea treated media. (iii) We also assessed the structural impact of the SNPs by analyzing differences in the structural conformation and calculating the root mean square deviation, which is a measure of the discordance of the Cα atoms between protein structures. Based on the above results, we propose that these analytical approaches serve as efficient methods for the identification of causal variants of human disease-causing genes and elucidation of yeast-cell based molecular mechanisms.
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Affiliation(s)
- Changshin Kim
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Jinmo Yang
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Su-Hyun Jeong
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Hayoung Kim
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Geun-hee Park
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Hwa Beom Shin
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - MyungJa Ro
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Kyoung-Yeon Kim
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - YoungJoon Park
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Keun Pil Kim
- Department of Life Sciences, College of Natural Sciences, Chung-Ang University, Seoul, Republic of Korea
| | - KyuBum Kwack
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
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13
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Pimentel E, Cruces MP. Antimutagenic action of the live yeast can be transmitted to the offspring of Drosophila melanogaster. A genetic study using the wing spot assay. Environ Toxicol Pharmacol 2018; 57:28-33. [PMID: 29172069 DOI: 10.1016/j.etap.2017.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/16/2017] [Indexed: 06/07/2023]
Abstract
The present study evaluates whether the protective effect of live yeast (LY) against direct and indirect mutagenic agents, persists in the offspring from individuals fed with LY. The wing-spot test in Drosophila was used; four different mates were performed: a) neither females nor males were fed with LY-enriched food (NLYxNLY); b) only females were fed (LYxNLY); c) males were fed (NLYxLY) or d) both progenitors were fed (LYxLY). Results confirm that LY strongly stimulates fecundity in females but not in males and provides strength to the egg for survive. A greater reduction in mutation rate was observed when females were feed, in the following relationship: LYxNLY>LYxLY>NLYxLY. No protection was found against action in any of the promutagens tested. Results suggest that LY has a very powerful antimutagenic action, predominantly against the action of ionizing radiation and Chromium trioxide that can be transmitted mainly through the female.
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Affiliation(s)
- Emilio Pimentel
- Departamento de Biología, Instituto Nacional de Investigaciones Nucleares (ININ), Carretera México-Toluca, S/N, La Marquesa, Ocoyoacac CP. 52750, Mexico.
| | - Martha P Cruces
- Departamento de Biología, Instituto Nacional de Investigaciones Nucleares (ININ), Carretera México-Toluca, S/N, La Marquesa, Ocoyoacac CP. 52750, Mexico
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14
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Habas K, Najafzadeh M, Baumgartner A, Brinkworth MH, Anderson D. An evaluation of DNA damage in human lymphocytes and sperm exposed to methyl methanesulfonate involving the regulation pathways associated with apoptosis. Chemosphere 2017; 185:709-716. [PMID: 28732331 DOI: 10.1016/j.chemosphere.2017.06.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/05/2017] [Indexed: 06/07/2023]
Abstract
Exposure to DNA-damaging agents produces a range of stress-related responses. These change the expression of genes leading to mutations that cause cell cycle arrest, induction of apoptosis and cancer. We have examined the contribution of haploid and diploid DNA damage and genes involved in the regulation of the apoptotic process associated with exposure, The Comet assay was used to detect DNA damage and quantitative RT-PCR analysis (qPCR) to detect gene expression changes in lymphocytes and sperm in response to methyl methanesulfonate. In the Comet assay, cells were administered 0-1.2 mM of MMS at 37 °C for 30 min for lymphocytes and 32 °C for 60 min for sperm to obtain optimal survival for both cell types. In the Comet assay a significant increase in Olive tail moment (OTM) and % tail DNA indicated DNA damage at increasing concentrations compared to the control group. In the qPCR study, cells were treated for 4 h, and RNA was isolated at the end of the treatment. qPCR analysis of genes associated with DNA stress responses showed that TP53 and CDKN1A are upregulated, while BCL2 is downregulated compared with the control. Thus, MMS caused DNA damage in lymphocytes at increasing concentrations, but appeared not to have the same effect in sperm at the low concentrations. These results indicate that exposure to MMS increased DNA damage and triggered the apoptotic response by activating TP53, CDKN1A and BCL2. These findings of the processing of DNA damage in human lymphocytes and sperm should be taken into account when genotoxic alterations in both cell types are produced when monitoring human exposure.
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Affiliation(s)
- Khaled Habas
- Division of Medical Sciences, Faculty of Life Sciences, University of Bradford, Richmond Road, Bradford, West Yorkshire, BD7 1DP, UK
| | - Mojgan Najafzadeh
- Division of Medical Sciences, Faculty of Life Sciences, University of Bradford, Richmond Road, Bradford, West Yorkshire, BD7 1DP, UK
| | - Adolf Baumgartner
- Division of Medical Sciences, Faculty of Life Sciences, University of Bradford, Richmond Road, Bradford, West Yorkshire, BD7 1DP, UK; School of Health Sciences, Biomedical Science, York St John University, Lord Mayor's Walk, York, YO31 7EX, UK
| | - Martin H Brinkworth
- Division of Medical Sciences, Faculty of Life Sciences, University of Bradford, Richmond Road, Bradford, West Yorkshire, BD7 1DP, UK
| | - Diana Anderson
- Division of Medical Sciences, Faculty of Life Sciences, University of Bradford, Richmond Road, Bradford, West Yorkshire, BD7 1DP, UK.
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15
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Townsend TA, Parrish MC, Engelward BP, Manjanatha MG. The development and validation of EpiComet-Chip, a modified high-throughput comet assay for the assessment of DNA methylation status. Environ Mol Mutagen 2017; 58:508-521. [PMID: 28755435 PMCID: PMC5839338 DOI: 10.1002/em.22101] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 04/25/2017] [Accepted: 04/28/2017] [Indexed: 05/10/2023]
Abstract
DNA damage and alterations in global DNA methylation status are associated with multiple human diseases and are frequently correlated with clinically relevant information. Therefore, assessing DNA damage and epigenetic modifications, including DNA methylation, is critical for predicting human exposure risk of pharmacological and biological agents. We previously developed a higher-throughput platform for the single cell gel electrophoresis (comet) assay, CometChip, to assess DNA damage and genotoxic potential. Here, we utilized the methylation-dependent endonuclease, McrBC, to develop a modified alkaline comet assay, "EpiComet," which allows single platform evaluation of genotoxicity and global DNA methylation [5-methylcytosine (5-mC)] status of single-cell populations under user-defined conditions. Further, we leveraged the CometChip platform to create an EpiComet-Chip system capable of performing quantification across simultaneous exposure protocols to enable unprecedented speed and simplicity. This system detected global methylation alterations in response to exposures which included chemotherapeutic and environmental agents. Using EpiComet-Chip on 63 matched samples, we correctly identified single-sample hypermethylation (≥1.5-fold) at 87% (20/23), hypomethylation (≥1.25-fold) at 100% (9/9), with a 4% (2/54) false-negative rate (FNR), and 10% (4/40) false-positive rate (FPR). Using a more stringent threshold to define hypermethylation (≥1.75-fold) allowed us to correctly identify 94% of hypermethylation (17/18), but increased our FPR to 16% (7/45). The successful application of this novel technology will aid hazard identification and risk characterization of FDA-regulated products, while providing utility for investigating epigenetic modes of action of agents in target organs, as the assay is amenable to cultured cells or nucleated cells from any tissue. Environ. Mol. Mutagen. 58:508-521, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Todd A. Townsend
- United States Food & Drug Administration, National Center for Toxicological Research, Division of Genetic and Molecular Toxicology, Jefferson, AR, USA
- Correspondence to: Todd Townsend, United States Food & Drug Administration, National Center for Toxicological Research, Division of Genetic and Molecular Toxicology, 3900 NCTR Road, Jefferson, AR, USA, ; Phone: +1 (870) 543-7155
| | - Marcus C. Parrish
- Massachusetts Institute of Technology, Department of Biological Engineering, Cambridge, MA, USA
| | - Bevin P. Engelward
- Massachusetts Institute of Technology, Department of Biological Engineering, Cambridge, MA, USA
| | - Mugimane G. Manjanatha
- United States Food & Drug Administration, National Center for Toxicological Research, Division of Genetic and Molecular Toxicology, Jefferson, AR, USA
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Li F, Zheng LD, Chen X, Zhao X, Briggs SD, Du HN. Gcn5-mediated Rph1 acetylation regulates its autophagic degradation under DNA damage stress. Nucleic Acids Res 2017; 45:5183-5197. [PMID: 28334815 PMCID: PMC5435933 DOI: 10.1093/nar/gkx129] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 02/12/2017] [Accepted: 02/14/2017] [Indexed: 12/31/2022] Open
Abstract
Histone modifiers regulate proper cellular activities in response to various environmental stress by modulating gene expression. In budding yeast, Rph1 transcriptionally represses many DNA damage or autophagy-related gene expression. However, little is known how Rph1 is regulated during these stress conditions. Here, we report that Rph1 is degraded upon DNA damage stress conditions. Notably, this degradation occurs via the autophagy pathway rather than through 26S proteasome proteolysis. Deletion of ATG genes or inhibition of vacuole protease activity compromises Rph1 turnover. We also determine that Rph1 and nuclear export protein Crm1 interact, which is required for Rph1 translocation from the nucleus to the cytoplasm. More importantly, Gcn5 directly acetylates Rph1 in vitro and in vivo, and Gcn5-containing complex, SAGA, is required for autophagic degradation of Rph1. Gcn5-mediated Rph1 acetylation is essential for the association of Rph1 with the nuclear pore protein Nup1. Finally, we show that sustaining high levels of Rph1 during DNA damage stress results in cell growth defects. Thus, we propose that Gcn5-mediated acetylation finely regulates Rph1 protein level and that autophagic degradation of Rph1 is important for cell homeostasis. Our findings may provide a general connection between DNA damage, protein acetylation and autophagy.
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Affiliation(s)
- Feng Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Liang-De Zheng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Xin Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Xiaolu Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Scott D. Briggs
- Department of Biochemistry and Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
| | - Hai-Ning Du
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
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17
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Habas K, Brinkworth MH, Anderson D. In vitro responses to known in vivo genotoxic agents in mouse germ cells. Environ Mol Mutagen 2017; 58:99-107. [PMID: 28205273 DOI: 10.1002/em.22075] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 01/29/2017] [Indexed: 06/06/2023]
Abstract
Genotoxic compounds have induced DNA damage in male germ cells and have been associated with adverse clinical outcomes including enhanced risks for maternal, paternal and offspring health. DNA strand breaks represent a great threat to the genomic integrity of germ cells. Such integrity is essential to maintain spermatogenesis and prevent reproduction failure. The Comet assay results revealed that the incubation of isolated germ cells with n-ethyl-n-nitrosourea (ENU), 6-mercaptopurine (6-MP) and methyl methanesulphonate (MMS) led to increase in length of Olive tail moment and % tail DNA when compared with the untreated control cells and these effects were concentration-dependent. All compounds were significantly genotoxic in cultured germ cells. Exposure of isolated germ cells to ENU produced the highest concentration-related increase in both DNA damage and gene expression changes in spermatogonia. Spermatocytes were most sensitive to 6-MP, with DNA damage and gene expression changes while spermatids were particularly susceptible to MMS. Real-time PCR results showed that the mRNA level expression of p53 increased and bcl-2 decreased significantly with the increasing ENU, 6-MP and MMS concentrations in spermatogonia, spermatocytes and spermatids respectively for 24 hr. Both are gene targets for DNA damage response and apoptosis. These observations may help explain the cell alterations caused by ENU, 6-MP and MMS in spermatogonia, spermatocytes and spermatids. Taken together, ENU, 6-MP and MMS induced DNA damage and decreased apoptosis associated gene expression in the germ cells in vitro. Environ. Mol. Mutagen. 58:99-107, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Khaled Habas
- School of Medical Sciences, University of Bradford, Bradford, BD7 1DP, United Kingdom
| | - Martin H Brinkworth
- School of Medical Sciences, University of Bradford, Bradford, BD7 1DP, United Kingdom
| | - Diana Anderson
- School of Medical Sciences, University of Bradford, Bradford, BD7 1DP, United Kingdom
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18
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Abstract
With the development of large-scale biologic databases, precision medicine is becoming a frontier in biomedical research. As a main focus of precision medicine study, cancer has been widely accepted as a disease born out of inherited genetic variations or accumulating genomic damage. At the single-cell level, microfluidics or lab-on-a-chip technology for cancer study is an emerging tool for improving risk assessment, diagnostic categories and therapeutic strategies. This work presents a multi-layer microchip for single-cell gene expression profiling. Treated by three drug reagents (i.e. methyl methanesulfonate, docetaxel and colchicine) with varied concentrations and time lengths, individual human breast cancer cells (MCF-7) are then lysed on-chip, and the released mRNA templates are captured and reversely transcribed into cDNA on microbead surface. Three genes (GAPDH, CDKN1A, AURKA) are amplified and quantified simultaneously through triplex real-time polymerase chain reactions (qPCR). Readout per run is set to be eighteen, and can be further improved following same approach. The microchip is able to integrate all steps of single-cell gene expression profiling, and provide precision study of drug induced genotoxicity with reduced reagents consumption per reaction and instrumental cost.
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Affiliation(s)
- Hui Dong
- School of Mechanical Engineering and Automation, Fuzhou University, Fujian 350116, China
| | - Hao Sun
- School of Mechanical Engineering and Automation, Fuzhou University, Fujian 350116, China.
| | - Jianping Zheng
- Department of Medical Oncology, Fujian Provincial Hospital, Fujian 350001, China
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19
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Andrade AF, Alves JM, Corrêa MB, Cunha WR, Veneziani RCS, Tavares DC. In vitro cytotoxicity, genotoxicity and antigenotoxicity assessment of Solanum lycocarpum hydroalcoholic extract. Pharm Biol 2016; 54:2786-2790. [PMID: 27159582 DOI: 10.1080/13880209.2016.1175022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
CONTEXT Solanum lycocarpum A. St.-Hil. (Solanaceae), popularly known as 'fruta-do-lobo' (wolf fruit), 'lobeira' and 'jurubebão', is commonly used by native people of Central Brazil in powder form or as a hydroalcoholic extract for the management of diabetes and obesity and to decrease cholesterol levels. OBJECTIVE The present study determines the possible cytotoxic, genotoxic and antigenotoxic activities of hydroalcoholic extract of the S. lycocarpum fruits (SL). MATERIALS AND METHODS The clonogenic efficiency assay was used to determine the cytotoxicity. Three concentrations of SL (16, 32 and 64 μg/mL) were used for the evaluation of its genotoxic and antigenotoxic potential on V79 cells using the micronucleus and comet assays. In the antigenotoxicity assays, the cells were treated simultaneously with SL and the alkylating agent methyl methanesulphonate (MMS, 44 μg/mL for the micronucleus assay and 22 μg/mL for the comet assay) as an inducer of micronuclei and DNA damage. RESULTS The results showed that SL was cytotoxic at concentrations up to 64 μg/mL. No significant differences in the rate of chromosome or DNA damage were observed between cultures treated with SL and the control group. In addition, the frequencies of micronuclei and DNA damage induced by MMS were significantly reduced after treatment with SL. The damage reduction percentage ranged from 68.1% to 79.2% and 12.1% to 16.5% for micronucleus and comet assays, respectively. DISCUSSION AND CONCLUSION SL exerted no genotoxic effect and exhibited chemopreventive activity against both genomic and chromosome damage induced by MMS.
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20
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Angeli JPF, Ribeiro LR, Bellini MF. Anti-clastogenic effect of b-glucan extracted from barley towards chemically induced DNA damage in rodent cells. Hum Exp Toxicol 2016; 25:319-24. [PMID: 16866189 DOI: 10.1191/0960327106ht631oa] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
b-Glucan (BG) was tested in vitro to determine its potential clastogenic and/or anti-clastogenic activity, and attempts were made to elucidate its possible mechanism of action by using combinations with an inhibitor of DNA polymerase. The study was carried out on cells deficient (CHO-k1) and cells proficient (HTC) in phases I and II enzymes, and the DNA damage was assessed by the chromosomal aberration assay. BG did not show a clastogenic effect, but was anti-clastogenic in both cell lines used, and at all concentrations tested (2.5, 5 and 10 mg/mL) in combination with damage inducing agents (methylmethane sulfonate in cell line CHO-k1, and methylmethane sulfonate or 2-aminoanthracene in cell line HTC). BG also showed a protective effect in the presence of a DNA polymerase b inhibitor (cytosine arabinoside-3-phosphate, Ara-C), demonstrating that BG does not act through an anti-mutagenic mechanism of action involving DNA polymerase b.
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Affiliation(s)
- J P F Angeli
- Departamento de Biologia Geral, Universidade Estadual de Londrina, Londrina, PR, Brazil
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Feng J, Duan Y, Sun W, Qin Y, Zhuang Z, Zhu D, Sun X, Jiang L. CaTip41 regulates protein phosphatase 2A activity, CaRad53 deactivation and the recovery of DNA damage-induced filamentation to yeast form in Candida albicans. FEMS Yeast Res 2016; 16:fow009. [PMID: 26851402 DOI: 10.1093/femsyr/fow009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2016] [Indexed: 02/07/2023] Open
Abstract
Phosphorylation and dephosphorylation of the checkpoint kinase CaRad53 is crucial for fungal cells in response to genotoxic stresses. The protein phosphatase 2A (PP2A) CaPph3/CaPsy2 phosphatase complex is involved in CaRad53 dephosphorylation in Candida albicans. In view of the role of ScTip41/ScTap42 in regulating PP2A phosphatases in Saccharomyces cerevisiae, we have explored the function of CaTip41 in C. albicans. Here, we show that CaTIP41 is a functional ortholog of ScTIP41 in the sensitivity of S. cerevisiae cells to rapamycin. Deletion of CaTIP41 causes C. albicans cells to be sensitive to DNA damaging agents, methylmethane sulfonate (MMS) and cisplatin, and resistant to both rapamycin and caffeine. Accordingly, expression of CaTip41 increases in response to MMS and cisplatin. In addition, C. albicans cells lacking CaTIP41 show a delay in the recovery from MMS-induced filamentation to yeast form, decreased PP2A activity and a defect in deactivation of CaRad53 during recovery from DNA damage. Through yeast two-hybrid assay we show that CaTip41 interacts with either CaPph3, CaPsy2 or CaTap42. Therefore, CaTip41 plays regulatory roles in both the CaRad53 deactivation during recovery from DNA damage and the target of rapamycin signaling pathway.
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Affiliation(s)
- Jinrong Feng
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, China
| | - Yinong Duan
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, China
| | - Wei Sun
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, China
| | - Yongwei Qin
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, China
| | - Zhong Zhuang
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, China
| | - Dandan Zhu
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, China
| | - Xiaolei Sun
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, China
| | - Linghuo Jiang
- The National Engineering Laboratory for Cereal Fermentation Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, China
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22
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Plappert-Helbig U, Guérard M. Inter-laboratory comparison of the in vivo comet assay including three image analysis systems. Environ Mol Mutagen 2015; 56:788-793. [PMID: 26248301 DOI: 10.1002/em.21964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 06/10/2015] [Accepted: 06/18/2015] [Indexed: 06/04/2023]
Abstract
To compare the extent of potential inter-laboratory variability and the influence of different comet image analysis systems, in vivo comet experiments were conducted using the genotoxicants ethyl methanesulfonate and methyl methanesulfonate. Tissue samples from the same animals were processed and analyzed-including independent slide evaluation by image analysis-in two laboratories with extensive experience in performing the comet assay. The analysis revealed low inter-laboratory experimental variability. Neither the use of different image analysis systems, nor the staining procedure of DNA (propidium iodide vs. SYBR® Gold), considerably impacted the results or sensitivity of the assay. In addition, relatively high stability of the staining intensity of propidium iodide-stained slides was found in slides that were refrigerated for over 3 months. In conclusion, following a thoroughly defined protocol and standardized routine procedures ensures that the comet assay is robust and generates comparable results between different laboratories.
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Affiliation(s)
- Ulla Plappert-Helbig
- Novartis Institutes for BioMedical Research, PreClinical Safety, 4057, Basel, Switzerland
| | - Melanie Guérard
- F. Hoffmann-La Roche AG, Roche Innovation Center Basel, Pharmaceutical Science, Pharma Research and Early Development, Basel, 4070, Switzerland
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23
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Kanemaru Y, Suzuki T, Niimi N, Grúz P, Matsumoto K, Adachi N, Honma M, Nohmi T. Catalytic and non-catalytic roles of DNA polymerase κ in the protection of human cells against genotoxic stresses. Environ Mol Mutagen 2015; 56:650-62. [PMID: 26031400 DOI: 10.1002/em.21961] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 05/13/2015] [Accepted: 05/26/2015] [Indexed: 05/07/2023]
Abstract
DNA polymerase κ (Pol κ) is a specialized DNA polymerase involved in translesion DNA synthesis. Although its bypass activities across lesions are well characterized in biochemistry, its cellular protective roles against genotoxic insults are still elusive. To better understand the in vivo protective roles, we have established a human cell line deficient in the expression of Pol κ (KO) and another expressing catalytically dead Pol κ (CD), to examine the cytotoxic sensitivity to 11 genotoxins including ultraviolet C light (UV). These cell lines were established in a genetic background of Nalm-6-MSH+, a human lymphoblastic cell line that has high efficiency for gene targeting, and functional p53 and mismatch repair activities. We classified the genotoxins into four groups. Group 1 includes benzo[a]pyrene diolepoxide, mitomycin C, and bleomycin, where the sensitivity was equally higher in KO and CD than in the cell line expressing wild-type Pol κ (WT). Group 2 includes hydrogen peroxide and menadione, where hypersensitivity was observed only in KO. Group 3 includes methyl methanesulfonate and ethyl methanesulfonate, where hypersensitivity was observed only in CD. Group 4 includes UV and three chemicals, where the chemicals exhibited similar cytotoxicity to all three cell lines. The results suggest that Pol κ not only protects cells from genotoxic DNA lesions via DNA polymerase activities, but also contributes to genome integrity by acting as a non-catalytic protein against oxidative damage caused by hydrogen peroxide and menadione. The non-catalytic roles of Pol κ in protection against oxidative damage by hydrogen peroxide are discussed.
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Affiliation(s)
- Yuki Kanemaru
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
- Division of Toxicology, Department of Pharmacology Toxicology and Therapeutics, Showa University School of Pharmacy, Shinagawa-Ku, Tokyo, 142-0064, Japan
| | - Tetsuya Suzuki
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
| | - Naoko Niimi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
| | - Petr Grúz
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
| | - Kyomu Matsumoto
- Toxicology Division, The Institute of Environmental Toxicology, Joso-Shi, Ibaraki, 303-0043, Japan
| | - Noritaka Adachi
- Graduate School of Nanobioscience, Yokohama City University, Yokohama, Kanagawa, 236-0027, Japan
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
| | - Takehiko Nohmi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
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Abstract
Experiments were performed to evaluate the in vitro and in vivo dose response for antigenotoxic effects of resveratrol (RES). For the in vitro study, HL-60 cells were co-treated with the test genotoxin and three concentrations of RES. Thereafter, genotoxic effects were assessed in the cytokinesis-block micronucleus test. Results of the in vitro experiments using genotoxins nitroquinoline-1-oxide (NQO) and mitomycin C (MMC) showed maximum inhibition of genotoxicity with the lowest test concentration of RES. The mouse bone marrow micronucleus assay was used for evaluating the in vivo antigenotoxic effects of RES against genotoxins diepoxybutane (DEB), MMC, methyl methanesulfonate and procarbazine (PCB). The experimental animals received RES pre-treatment by gavage 30min, 24 and 48h before injecting the genotoxin intraperitoneally. The in vivo studies demonstrated efficacy of the lowest test dose of RES for exerting maximum protection against chromosomal damage induced by all four genotoxins. The antigenotoxic effect observed with 6.25mg/kg RES was significantly higher than that of 100mg/kg RES against PCB and DEB. In conclusion, the findings from the present study indicate that lower test concentrations/doses of RES are more effective in exerting antigenotoxic effects.
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Affiliation(s)
| | | | - Henning Hintzsche
- Institut für Pharmakologie und Toxikologie, Universität Würzburg 97078, Würzburg, Germany
| | - Helga Stopper
- Institut für Pharmakologie und Toxikologie, Universität Würzburg 97078, Würzburg, Germany
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25
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Bi X, Yu Q, Siler J, Li C, Khan A. Functions of Fun30 chromatin remodeler in regulating cellular resistance to genotoxic stress. PLoS One 2015; 10:e0121341. [PMID: 25806814 PMCID: PMC4373758 DOI: 10.1371/journal.pone.0121341] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/30/2015] [Indexed: 01/14/2023] Open
Abstract
The Saccharomyces cerevisiae Fun30 chromatin remodeler has recently been shown to facilitate long-range resection of DNA double strand break (DSB) ends, which proceeds homologous recombination (HR). This is believed to underlie the role of Fun30 in promoting cellular resistance to DSB inducing agent camptothecin. We show here that Fun30 also contributes to cellular resistance to genotoxins methyl methanesulfonate (MMS) and hydroxyurea (HU) that can stall the progression of DNA replication. We present evidence implicating DNA end resection in Fun30-dependent MMS-resistance. On the other hand, we show that Fun30 deletion suppresses the MMS- and HU-sensitivity of cells lacking the Rad5/Mms2/Ubc13-dependent error-free DNA damage tolerance mechanism. This suppression is not the result of a reduction in DNA end resection, and is dependent on the key HR component Rad51. We further show that Fun30 negatively regulates the recovery of rad5Δ mutant from MMS induced G2/M arrest. Therefore, Fun30 has two functions in DNA damage repair: one is the promotion of cellular resistance to genotoxic stress by aiding in DNA end resection, and the other is the negative regulation of a Rad51-dependent, DNA end resection-independent mechanism for countering replicative stress. The latter becomes manifest when Rad5 dependent DNA damage tolerance is impaired. In addition, we find that the putative ubiquitin-binding CUE domain of Fun30 serves to restrict the ability of Fun30 to hinder MMS- and HU-tolerance in the absence of Rad5.
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Affiliation(s)
- Xin Bi
- Department of Biology, University of Rochester, Rochester, New York, United States of America
- * E-mail:
| | - Qun Yu
- Department of Biology, University of Rochester, Rochester, New York, United States of America
| | - Jasmine Siler
- Department of Biology, University of Rochester, Rochester, New York, United States of America
| | - Chong Li
- Department of Biology, University of Rochester, Rochester, New York, United States of America
| | - Ali Khan
- Department of Biology, University of Rochester, Rochester, New York, United States of America
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26
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Piya G, Mueller EN, Haas HK, Ghospurkar PL, Wilson TM, Jensen JL, Colbert CL, Haring SJ. Characterization of the interaction between Rfa1 and Rad24 in Saccharomyces cerevisiae. PLoS One 2015; 10:e0116512. [PMID: 25719602 PMCID: PMC4342240 DOI: 10.1371/journal.pone.0116512] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 12/10/2014] [Indexed: 11/22/2022] Open
Abstract
Maintaining the integrity of the genome requires the high fidelity duplication of the genome and the ability of the cell to recognize and repair DNA lesions. The heterotrimeric single stranded DNA (ssDNA) binding complex Replication Protein A (RPA) is central to multiple DNA processes, which are coordinated by RPA through its ssDNA binding function and through multiple protein-protein interactions. Many RPA interacting proteins have been reported through large genetic and physical screens; however, the number of interactions that have been further characterized is limited. To gain a better understanding of how RPA functions in DNA replication, repair, and cell cycle regulation and to identify other potential functions of RPA, a yeast two hybrid screen was performed using the yeast 70 kDa subunit, Replication Factor A1 (Rfa1), as a bait protein. Analysis of 136 interaction candidates resulted in the identification of 37 potential interacting partners, including the cell cycle regulatory protein and DNA damage clamp loader Rad24. The Rfa1-Rad24 interaction is not dependent on ssDNA binding. However, this interaction appears affected by DNA damage. The regions of both Rfa1 and Rad24 important for this interaction were identified, and the region of Rad24 identified is distinct from the region reported to be important for its interaction with Rfc2 5. This suggests that Rad24-Rfc2-5 (Rad24-RFC) recruitment to DNA damage substrates by RPA occurs, at least partially, through an interaction between the N terminus of Rfa1 and the C terminus of Rad24. The predicted structure and location of the Rad24 C-terminus is consistent with a model in which RPA interacts with a damage substrate, loads Rad24-RFC at the 5’ junction, and then releases the Rad24-RFC complex to allow for proper loading and function of the DNA damage clamp.
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Affiliation(s)
- Gunjan Piya
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND, 58108, United States of America
| | - Erica N. Mueller
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND, 58108, United States of America
| | - Heather K. Haas
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND, 58108, United States of America
| | - Padmaja L. Ghospurkar
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND, 58108, United States of America
| | - Timothy M. Wilson
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND, 58108, United States of America
| | - Jaime L. Jensen
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND, 58108, United States of America
| | - Christopher L. Colbert
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND, 58108, United States of America
- Interdisciplinary Program in Cellular and Molecular Biology, North Dakota State University, Fargo, ND, 58108, United States of America
| | - Stuart J. Haring
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND, 58108, United States of America
- Interdisciplinary Program in Cellular and Molecular Biology, North Dakota State University, Fargo, ND, 58108, United States of America
- * E-mail:
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27
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Bausinger J, Speit G. Induction and repair of DNA damage measured by the comet assay in human T lymphocytes separated by immunomagnetic cell sorting. Mutat Res 2014; 769:42-48. [PMID: 25771724 DOI: 10.1016/j.mrfmmm.2014.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 07/01/2014] [Accepted: 07/11/2014] [Indexed: 06/04/2023]
Abstract
The comet assay is widely used in human biomonitoring to measure DNA damage in whole blood or isolated peripheral blood mononuclear cells (PBMC) as a marker of exposure to genotoxic agents. Cytogenetic assays with phytohemagglutinin (PHA)-stimulated cultured T lymphocytes are also frequently performed in human biomonitoring. Cytogenetic effects (micronuclei, chromosome aberrations, sister chromatid exchanges) may be induced in vivo but also occur ex vivo during the cultivation of lymphocytes as a consequence of DNA damage present in lymphocytes at the time of sampling. To better understand whether DNA damage measured by the comet assay in PBMC is representative for DNA damage in T cells, we comparatively investigated DNA damage and its repair in PBMC and T cells obtained by immunomagnetic cell sorting. PBMC cultures and T cell cultures were exposed to mutagens with different modes of genotoxic action and DNA damage was measured by the comet assay after the end of a 2h exposure and after 18h post-incubation. The mutagens tested were methyl methanesulfonate (MMS), (±)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), 4-nitroquinoline-1-oxide (4NQO), styrene oxide and potassium bromate. MMS and potassium bromate were also tested by the modified comet assay with formamido pyrimidine glycosylase (FPG) protein. The results indicate that the mutagens tested induce DNA damage in PBMC and T cells in the same range of concentrations and removal of induced DNA lesions occurs to a comparable extent. Based on these results, we conclude that the comet assay with PBMC is suited to predict DNA damage and its removal in T cells.
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Affiliation(s)
- Julia Bausinger
- Universität Ulm, Institut für Humangenetik, 89069 Ulm, Germany
| | - Günter Speit
- Universität Ulm, Institut für Humangenetik, 89069 Ulm, Germany.
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28
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Johnson GE, Soeteman-Hernández LG, Gollapudi BB, Bodger OG, Dearfield KL, Heflich RH, Hixon JG, Lovell DP, MacGregor JT, Pottenger LH, Thompson CM, Abraham L, Thybaud V, Tanir JY, Zeiger E, van Benthem J, White PA. Derivation of point of departure (PoD) estimates in genetic toxicology studies and their potential applications in risk assessment. Environ Mol Mutagen 2014; 55:609-23. [PMID: 24801602 PMCID: PMC6710644 DOI: 10.1002/em.21870] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/07/2014] [Accepted: 04/11/2014] [Indexed: 05/13/2023]
Abstract
Genetic toxicology data have traditionally been employed for qualitative, rather than quantitative evaluations of hazard. As a continuation of our earlier report that analyzed ethyl methanesulfonate (EMS) and methyl methanesulfonate (MMS) dose-response data (Gollapudi et al., 2013), here we present analyses of 1-ethyl-1-nitrosourea (ENU) and 1-methyl-1-nitrosourea (MNU) dose-response data and additional approaches for the determination of genetic toxicity point-of-departure (PoD) metrics. We previously described methods to determine the no-observed-genotoxic-effect-level (NOGEL), the breakpoint-dose (BPD; previously named Td), and the benchmark dose (BMD10 ) for genetic toxicity endpoints. In this study we employed those methods, along with a new approach, to determine the non-linear slope-transition-dose (STD), and alternative methods to determine the BPD and BMD, for the analyses of nine ENU and 22 MNU datasets across a range of in vitro and in vivo endpoints. The NOGEL, BMDL10 and BMDL1SD PoD metrics could be readily calculated for most gene mutation and chromosomal damage studies; however, BPDs and STDs could not always be derived due to data limitations and constraints of the underlying statistical methods. The BMDL10 values were often lower than the other PoDs, and the distribution of BMDL10 values produced the lowest median PoD. Our observations indicate that, among the methods investigated in this study, the BMD approach is the preferred PoD for quantitatively describing genetic toxicology data. Once genetic toxicology PoDs are calculated via this approach, they can be used to derive reference doses and margin of exposure values that may be useful for evaluating human risk and regulatory decision making.
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Affiliation(s)
- G E Johnson
- Institute of Life Science, College of Medicine, Swansea University, Swansea, Wales, United Kingdom
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29
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Pant K, Springer S, Bruce S, Lawlor T, Hewitt N, Aardema MJ. Vehicle and positive control values from the in vivo rodent comet assay and biomonitoring studies using human lymphocytes: historical database and influence of technical aspects. Environ Mol Mutagen 2014; 55:633-42. [PMID: 24957907 DOI: 10.1002/em.21881] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Accepted: 06/06/2014] [Indexed: 05/27/2023]
Abstract
There is increased interest in the in vivo comet assay in rodents as a follow-up approach for determining the biological relevance of chemicals that are genotoxic in in vitro assays. This is partly because, unlike other assays, DNA damage can be assessed in this assay in virtually any tissue. Since background levels of DNA damage can vary with the species, tissue, and cell processing method, a robust historical control database covering multiple tissues is essential. We describe extensive vehicle and positive control data for multiple tissues from rats and mice. In addition, we report historical data from control and genotoxin-treated human blood. Technical issues impacting comet results are described, including the method of cell preparation and freezing. Cell preparation by scraping (stomach and other GI tract organs) resulted in higher % tail DNA than mincing (liver, spleen, kidney etc) or direct collection (blood or bone marrow). Treatment with the positive control genotoxicant, ethyl methanesulfonate (EMS) in rats and methyl methanesulfonate in mice, resulted in statistically significant increases in % tail DNA. Background DNA damage was not markedly increased when cell suspensions were stored frozen prior to preparing slides, and the outcome of the assay was unchanged (EMS was always positive). In conclusion, historical data from our laboratory for the in vivo comet assay for multiple tissues from rats and mice, as well as human blood show very good reproducibility. These data and recommendations provided are aimed at contributing to the design and proper interpretation of results from comet assays.
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Affiliation(s)
- Kamala Pant
- BioReliance Corporation, Rockville, Maryland
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30
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Hoshina MM, Marin-Morales MA. Anti-genotoxicity and anti-mutagenicity of Apis mellifera venom. Mutat Res Genet Toxicol Environ Mutagen 2014; 762:43-8. [PMID: 24525379 DOI: 10.1016/j.mrgentox.2013.11.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 08/16/2013] [Accepted: 11/02/2013] [Indexed: 11/30/2022]
Abstract
The search for substances able to inhibit and/or diminish the effects of genotoxic and mutagenic substances has been the target of several investigations performed in recent times. Hymenoptera venoms constitute a considerable source of substances with pharmacological potential. The present study aimed to evaluate the cytotoxic, genotoxic and anti-genotoxic, mutagenic and anti-mutagenic potentials of Apis mellifera venom in HepG2 cells. In this evaluation, the MTT test was applied to determine the most appropriate concentrations for the genotoxicity and mutagenicity tests. It was verified that the concentrations of 0.1, 0.05 and 0.01μg/mL were not cytotoxic, hence these concentrations were used in the experiments. For the evaluation of the genotoxic and mutagenic potential of the bee venom the comet assay and the micronucleus test were applied, respectively. The concentrations mentioned above presented both genotoxic and mutagenic potential for HepG2 cells and it was necessary to test lower concentrations of the venom (10pg/mL, 1pg/mL and 0.1pg/mL) for the anti-genotoxicity and anti-mutagenicity tests, which were performed subjecting the cells to the action of MMS (methyl methanesulfonate) in order to verify the ability of the venom to inhibit or diminish the action of this compound, which has a recognized action on the genetic material. Pre-, post-treatment and simultaneous treatment with and without incubation with the venom were performed. It was observed that the lowest three concentrations tested did not present any anti-genotoxic and anti-mutagenic activity on the cells. The use of bee venom for pharmacological purposes in treatments such as cancer must be done with extreme caution, since it was observed that even at very low concentrations the venom can induce genotoxicity and mutagenicity in human cells, as was verified for the HepG2 cells.
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Affiliation(s)
- Márcia Miyuki Hoshina
- Departamento de Biologia, Instituto de Biociências, UNESP, Avenida 24 A, 1515, CP 199, 13506-900 Rio Claro, SP, Brazil
| | - Maria Aparecida Marin-Morales
- Departamento de Biologia, Instituto de Biociências, UNESP, Avenida 24 A, 1515, CP 199, 13506-900 Rio Claro, SP, Brazil.
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31
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Tang L, Guérard M, Zeller A. Quantitative assessment of the dose-response of alkylating agents in DNA repair proficient and deficient ames tester strains. Environ Mol Mutagen 2014; 55:15-23. [PMID: 24273186 DOI: 10.1002/em.21825] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 10/04/2013] [Accepted: 10/04/2013] [Indexed: 06/02/2023]
Abstract
Mutagenic and clastogenic effects of some DNA damaging agents such as methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) have been demonstrated to exhibit a nonlinear or even "thresholded" dose-response in vitro and in vivo. DNA repair seems to be mainly responsible for these thresholds. To this end, we assessed several mutagenic alkylators in the Ames test with four different strains of Salmonella typhimurium: the alkyl transferases proficient strain TA1535 (Ogt+/Ada+), as well as the alkyl transferases deficient strains YG7100 (Ogt+/Ada-), YG7104 (Ogt-/Ada+) and YG7108 (Ogt-/Ada-). The known genotoxins EMS, MMS, temozolomide (TMZ), ethylnitrosourea (ENU) and methylnitrosourea (MNU) were tested in as many as 22 concentration levels. Dose-response curves were statistically fitted by the PROAST benchmark dose model and the Lutz-Lutz "hockeystick" model. These dose-response curves suggest efficient DNA-repair for lesions inflicted by all agents in strain TA1535. In the absence of Ogt, Ada is predominantly repairing methylations but not ethylations. It is concluded that the capacity of alkyl-transferases to successfully repair DNA lesions up to certain dose levels contributes to genotoxicity thresholds.
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Affiliation(s)
- Leilei Tang
- pRED, Pharma Research and Early Development, F. Hoffmann-La Roche Ltd., Basel, Switzerland
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32
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Faßbender C, Braunbeck T. Assessment of genotoxicity in gonads, liver and gills of zebrafish (Danio rerio) by use of the comet assay and micronucleus test after in vivo exposure to methyl methanesulfonate. Bull Environ Contam Toxicol 2013; 91:89-95. [PMID: 23620131 DOI: 10.1007/s00128-013-1007-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/19/2013] [Indexed: 06/02/2023]
Abstract
Since generative tissues are a link between the generations, the detection of genetic damage in testis and ovary of fish is conductive to elucidating the relationship between genotoxicity and impairment of reproduction. In the current study, exposure of zebrafish to methyl methanesulfonate over two weeks caused concentration dependent genotoxic effects in gonads, liver and gills using the alkaline comet assay. Likewise, the micronucleus frequency was elevated in all of these organs. Thus, the comet assay and the micronucleus test proved appropriate for the detection of genotoxicity in primary male and female gonad cells and histological sections of the gonads from zebrafish, respectively.
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Affiliation(s)
- Christopher Faßbender
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
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33
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Faßbender C, Braunbeck T. Reproductive and genotoxic effects in zebrafish after chronic exposure to methyl methanesulfonate in a multigeneration study. Ecotoxicology 2013; 22:825-837. [PMID: 23483329 DOI: 10.1007/s10646-013-1057-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/28/2013] [Indexed: 06/01/2023]
Abstract
There is still controversy whether adverse effects by genotoxic anthropogenic pollutants are linked to the decline of fish populations. Further investigations into the relationship between genotoxic stress and detrimental effects on development and reproduction in fish are required. For this end, zebrafish (F0 generation) were exposed in vivo to the alkylating model genotoxin methyl methanesulfonate (MMS) from fertilization to the age of 1 year. F0 fish were mated over 6 months to check for reproductive capacities. F1 fish grew up without exposure in order to allow for regeneration. Mortality of F0 fish depended on MMS concentrations. In MMS-exposed F0 fish, times of first spawning were delayed and fertility was reduced. Using the alkaline comet assay and the micronucleus test, significant genotoxic effects were found in the livers, gills and gonads of either sex in the F0 generation. No detrimental effects on growth were found. In F1 fish with parental exposure, teratogenic effects were increased, and larval survival was reduced. However, fertility capacities of the non-exposed F1 generation had recovered. Development and survival rates further recovered in the F2 generation. Anthropogenic genotoxicants may thus play a considerable role in the decline of wild fish populations.
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Affiliation(s)
- Christopher Faßbender
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
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34
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Santos R, Palos-Ladeiro M, Besnard A, Reggio J, Vulliet E, Porcher JM, Bony S, Sanchez W, Devaux A. Parental exposure to methyl methane sulfonate of three-spined stickleback: contribution of DNA damage in male and female germ cells to further development impairment in progeny. Ecotoxicology 2013; 22:815-824. [PMID: 23744483 DOI: 10.1007/s10646-013-1088-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/21/2013] [Indexed: 06/02/2023]
Abstract
Data regarding the link between DNA integrity of germ cells and the quality of progeny in fish exposed to genotoxicant are scarce although such information is of value to understand genotoxic effects of contaminants in aquatic fauna. This work aimed at studying the consequences of a parental exposure during the breeding season on offspring quality in three-spined stickleback. After in vivo exposure of adult fish to methyl methane sulfonate, a model alkylating compound, a clear increase in DNA damage was observed in erythrocytes of both genders, here used as a biomarker of exposure. MMS exposure significantly affected sperm DNA integrity but neither female fecundity nor fertilization success. In order to understand the contribution of each sex to potential deleterious effects in progeny due to parental exposure, mating of males and females exposed or not to MMS, was carried out. Exposure of both males and females or of males alone led to a significant increase in both mortality during embryo-larval stages and abnormality rate at hatching that appeared to be sensitive stages. Thus, in accordance with recent studies carried out in other freshwater fish species, such development defects in progeny were clearly driven by male genome, known to be devoid of DNA repair capacity in spermatozoa. The next step will be to investigate the link between DNA damage in stickleback sperm and reproductive impairment in natural populations exposed to complex mixture of genotoxicants.
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Affiliation(s)
- R Santos
- Université de Lyon, UMR 5023 LEHNA, 69100 Villeurbanne, France
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35
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Patenković A, Stamenković-Radak M, Nikolić D, Marković T, Anđelković M. Synergistic effect of Gentiana lutea L. on methyl methanesulfonate genotoxicity in the Drosophila wing spot test. J Ethnopharmacol 2013; 146:632-636. [PMID: 23384783 DOI: 10.1016/j.jep.2013.01.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/11/2013] [Accepted: 01/19/2013] [Indexed: 06/01/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Gentiana lutea L., the yellow gentian, is herb known for its pharmacological properties, with a long tradition of use for the treatment of a variety of diseases including the use as a remedy for digestion, also in food products and in bitter beverages. The aim of the present study is to evaluate, for the first time, genotoxicity of gentian alone, and its antigenotoxicity against methyl methanesulfonate (MMS). MATERIALS AND METHODS The water infusion of the underground part of gentian were evaluated in vivo using the Drosophila wing spot test, at the dose commonly used in traditional medicine. For antigenotoxic study two types of treatment with gentian and MMS were performed: chronic co-treatment, as well as post-treatment with gentian after acute exposure with MMS. RESULTS Water infusion of gentian alone did not exhibit genotoxicity. The results of co- and post-treatment experiments with gentian show that gentian enhanced the frequency of mutant clones over the values obtained with MMS alone, instead of reducing the genotoxicity of MMS, for 22.64% and 27.13% respectively. CONCLUSIONS This result suggests a synergism of gentian with MMS, and indicates that water infusion of gentian used in traditional medicine may have particular effects with regard to genotoxicity indicating careful use.
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Affiliation(s)
- Aleksandra Patenković
- Institute for Biological Research Siniša Stanković, Department of Genetics of Populations and Ecogenotoxicology, University of Belgrade, Bul. despota Stefana 142, 11060 Belgrade, Serbia.
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36
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Tennen RI, Haye JE, Wijayatilake HD, Arlow T, Ponzio D, Gammie AE. Cell-cycle and DNA damage regulation of the DNA mismatch repair protein Msh2 occurs at the transcriptional and post-transcriptional level. DNA Repair (Amst) 2013; 12:97-109. [PMID: 23261051 PMCID: PMC3749301 DOI: 10.1016/j.dnarep.2012.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 10/03/2012] [Accepted: 11/06/2012] [Indexed: 12/13/2022]
Abstract
DNA mismatch repair during replication is a conserved process essential for maintaining genomic stability. Mismatch repair is also implicated in cell-cycle arrest and apoptosis after DNA damage. Because yeast and human mismatch repair systems are well conserved, we have employed the budding yeast Saccharomyces cerevisiae to understand the regulation and function of the mismatch repair gene MSH2. Using a luciferase-based transcriptional reporter, we defined a 218-bp region upstream of MSH2 that contains cell-cycle and DNA damage responsive elements. The 5' end of the MSH2 transcript was mapped by primer extension and was found to encode a small upstream open reading frame (uORF). Mutagenesis of the uORF start codon or of the uORF stop codon, which creates a continuous reading frame with MSH2, increased Msh2 steady-state protein levels ∼2-fold. Furthermore, we found that the cell-cycle transcription factors Swi6, Swi4, and Mbp1-along with SCB/MCB cell-cycle binding sites upstream of MSH2-are all required for full basal expression of MSH2. Mutagenesis of the cell-cycle boxes resulted in a minor reduction in basal Msh2 levels and a 3-fold defect in mismatch repair. Disruption of the cell-cycle boxes also affected growth in a DNA polymerase-defective strain background where mismatch repair is essential, particularly in the presence of the DNA damaging agent methyl methane sulfonate (MMS). Promoter replacements conferring constitutive expression of MSH2 revealed that the transcriptional induction in response to MMS is required to maintain induced levels of Msh2. Turnover experiments confirmed an elevated rate of degradation in the presence of MMS. Taken together, the data show that the DNA damage regulation of Msh2 occurs at the transcriptional and post-transcriptional levels. The transcriptional and translational control elements identified are conserved in mammalian cells, underscoring the use of yeast as a model system to examine the regulation of MSH2.
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Affiliation(s)
- Ruth I. Tennen
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, United States
| | - Joanna E. Haye
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, United States
| | | | - Tim Arlow
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, United States
| | - Danielle Ponzio
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, United States
| | - Alison E. Gammie
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, United States
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Francielli de Oliveira P, Furtado RA, Acésio NO, Leandro LF, Montanheiro G, de Pádua FC, Corrêa MB, Braguini CG, Pauletti PM, Tavares DC. In vivo protective activity of Styrax camporum hydroalcoholic extract against genotoxicity induced by doxorubicin and methyl methanesulfonate in the micronucleus and comet assays. Planta Med 2012; 78:1899-1905. [PMID: 23254694 DOI: 10.1055/s-0032-1327901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Styrax camporum Pohl is a tall shrub or a tree with small white flowers, which grows in the states of São Paulo and Minas Gerais and is popularly used for the treatment of gastroduodenal diseases. Considering this last fact, the aim of this study was to evaluate the genotoxic potential of S. camporum hydroalcoholic extract and its influence on genotoxicity induced by doxorubicin and methyl methanesulfonate in Swiss mice using the micronucleus and comet assays, respectively. The animals were treated by gavage with different doses of the extract (250, 500, and 1000 mg/kg body weight). For antigenotoxicity assessment, different doses of the S. camporum extract were administered simultaneously with doxorubicin (micronucleus test; 15 mg/kg) and methanesulfonate (comet assay; 40 mg/kg). The results showed that the S. camporum extract itself was not genotoxic in the mouse micronucleus or comet assay. The number of micronucleated polychromatic erythrocytes was significantly lower in animals treated with the S. camporum extract and doxorubicin when compared to animals treated only with doxorubicin. In the comet assay, the S. camporum extract, at the doses tested, significantly reduced the extent of DNA damage in liver cells induced by methanesulfonate. The putative activity of the active compounds of S. camporum extract may explain the effect of this plant on genotoxicity induced by doxorubicin and methanesulfonate.
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Loram J, Raudonis R, Chapman J, Lortie M, Bodnar A. Sea urchin coelomocytes are resistant to a variety of DNA damaging agents. Aquat Toxicol 2012; 124-125:133-138. [PMID: 22948035 DOI: 10.1016/j.aquatox.2012.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/07/2012] [Accepted: 08/07/2012] [Indexed: 06/01/2023]
Abstract
Increasing anthropogenic activities are creating environmental pressures that threaten marine ecosystems. Effective environmental health assessment requires the development of rapid, sensitive, and cost-effective tools to predict negative impacts at the individual and ecosystem levels. To this end, a number of biological assays using a variety of cells and organisms measuring different end points have been developed for biomonitoring programs. The sea urchin fertilization/development test has been useful for evaluating environmental toxicology and it has been proposed that sea urchin coelomocytes represent a novel cellular biosensor of environmental stress. In this study we investigated the sensitivity of coelomocytes from the sea urchin Lytechinus variegatus to a variety of DNA-damaging agents including ultraviolet (UV) radiation, hydrogen peroxide (H(2)O(2)), methylmethane sulfonate (MMS) and benzo[a]pyrene (BaP). LD(50) values determined for coelomocytes after 24h of exposure to these DNA damaging agents indicated a high level of resistance to all treatments. Significant increases in the formation of apurinic/apyrimidinic (AP or abasic) sites in DNA were only detected using high doses of H(2)O(2), MMS and UV radiation. Comparison of sea urchin coelomocytes with hemocytes from the gastropod mollusk Aplysia dactylomela and the decapod crustacean Panulirus argus indicated that sensitivity to different DNA damaging agents varies between species. The high level of resistance to genotoxic agents suggests that DNA damage may not be an informative end point for environmental health assessment using sea urchin coelomocytes however, natural resistance to DNA damaging agents may have implications for the occurrence of neoplastic disease in these animals.
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Affiliation(s)
- Jeannette Loram
- Bermuda Institute of Ocean Sciences, St. George's, Bermuda, Bermuda
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Jiang Y, Zhang XY, Sun L, Zhang GL, Duerksen-Hughes P, Zhu XQ, Yang J. Methyl methanesulfonate induces apoptosis in p53-deficient H1299 and Hep3B cells through a caspase 2- and mitochondria-associated pathway. Environ Toxicol Pharmacol 2012; 34:694-704. [PMID: 23117069 DOI: 10.1016/j.etap.2012.09.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 09/19/2012] [Accepted: 09/30/2012] [Indexed: 06/01/2023]
Abstract
Methyl methanesulfonate (MMS) has been shown to induce apoptosis in various cell types through p53-dependent pathways. Nevertheless, pharmacological and genetic blockade of p53 functions results in similar or delayed sensitivity to MMS treatment, suggesting the presence of p53-independent apoptotic mechanisms. To understand the p53-independent mechanisms that are engaged during MMS-induced apoptosis, we established MMS-induced apoptotic cell models using p53-deficient H1299 and Hep3B cells. Our results demonstrated that MMS at concentrations of 50, 100, 200, 400 and 800 μM induced the formation of gammaH2AX foci, and that at higher concentrations, 400 and 800 μM, MMS treatment led to apoptosis in the two cell lines. This apoptotic cell death was concurrent with the loss of mitochondrial membrane potential, nuclear-cytosolic translocation of active caspase 2, release of cytochrome c from mitochondria, and the cleavage of caspase 9, caspase 3 and PARP. However, MMS-induced DNA damage failed to stabilize the p53 family members TAp73 and DNp73. These results demonstrated a p53- and p73-independent mechanism for MMS-induced apoptosis that involves the nuclear-cytosolic translocation of active caspase 2 as well as the mitochondria-mediated pathway.
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Affiliation(s)
- Ying Jiang
- The First Affiliated Hospital, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, Zhejiang 310003, China
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Vincent-Hubert F, Revel M, Garric J. DNA strand breaks detected in embryos of the adult snails, Potamopyrgus antipodarum, and in neonates exposed to genotoxic chemicals. Aquat Toxicol 2012; 122-123:1-8. [PMID: 22717255 DOI: 10.1016/j.aquatox.2012.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 05/03/2012] [Accepted: 05/14/2012] [Indexed: 06/01/2023]
Abstract
We tested the freshwater mudsnail Potamopyrgus antipodarum, which is a species that has already been used for endocrine-disrupting compounds (EDCs) to determine whether early life stages of aquatic organisms are sensitive to genotoxic chemicals. For this purpose, we first developed the alkaline comet assay on adults, embryos, and neonates. The comet assay protocol was validated on both embryonic cells exposed in vitro to hydrogen peroxide and adult snails in the reproducing stage exposed to methyl methane sulfonate. During the latter experiment, DNA strand breaks were investigated on both embryonic cells and on adult gill cells. The second part of this study investigated the stability of DNA strand breaks in adult reproducing snails and neonates exposed to cadmium (Cd) and bisphenol A for 8 days. Hydrogen peroxide-induced DNA strand breaks in vitro in isolated embryonic cells. Exposure of adult reproducing snails to methyl methane sulfonate for 24h induced DNA strand breaks in embryos. Bisphenol A induced a significant increase in the DNA strand-break level in whole embryonic cells and whole neonate cells. Cd was genotoxic for both embryos and neonates during the exposure time and also after 7 days of depuration, suggesting that Cd could inhibit DNA repair enzymes. These preliminary results on this original model have encouraged us to consider the impact of genotoxic environmental contaminants on the F1 generation.
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Donigan KA, Sun KW, Nemec AA, Murphy DL, Cong X, Northrup V, Zelterman D, Sweasy JB. Human POLB gene is mutated in high percentage of colorectal tumors. J Biol Chem 2012; 287:23830-9. [PMID: 22577134 PMCID: PMC3390656 DOI: 10.1074/jbc.m111.324947] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 05/10/2012] [Indexed: 12/11/2022] Open
Abstract
Previous small scale sequencing studies have indicated that DNA polymerase β (pol β) variants are present on average in 30% of human tumors of varying tissue origin. Many of these variants have been shown to have aberrant enzyme function in vitro and to induce cellular transformation and/or genomic instability in vivo, suggesting that their presence is associated with tumorigenesis or its progression. In this study, the human POLB gene was sequenced in a collection of 134 human colorectal tumors and was found to contain coding region mutations in 40% of the samples. The variants map to many different sites of the pol β protein and are not clustered. Many variants are nonsynonymous amino acid substitutions predicted to affect enzyme function. A subset of these variants was found to have reduced enzyme activity in vitro and failed to fully rescue pol β-deficient cells from methylmethane sulfonate-induced cytotoxicity. Tumors harboring variants with reduced enzyme activity may have compromised base excision repair function, as evidenced by our methylmethane sulfonate sensitivity studies. Such compromised base excision repair may drive tumorigenesis by leading to an increase in mutagenesis or genomic instability.
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Affiliation(s)
| | - Ka-wai Sun
- From the Departments of Therapeutic Radiology and Genetics and
| | | | - Drew L. Murphy
- From the Departments of Therapeutic Radiology and Genetics and
| | - Xiangyu Cong
- Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Veronika Northrup
- Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Daniel Zelterman
- Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Joann B. Sweasy
- From the Departments of Therapeutic Radiology and Genetics and
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Sousa C, Fernandes F, Valentão P, Rodrigues AS, Coelho M, Teixeira JP, Silva S, Ferreres F, Guedes de Pinho P, Andrade PB. Brassica oleracea L. Var. costata DC and Pieris brassicae L. aqueous extracts reduce methyl methanesulfonate-induced DNA damage in V79 hamster lung fibroblasts. J Agric Food Chem 2012; 60:5380-5387. [PMID: 22582708 DOI: 10.1021/jf300941s] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Brassica oleracea L. var. costata DC leaves and Pieris brassicae L. larvae aqueous extracts were assayed for their potential to prevent/induce DNA damage. None of them was mutagenic at the tested concentrations in the Ames test reversion assay using Salmonella His(+) TA98 strains, with and without metabolic activation. In the hypoxanthine-guanine phosphoribosyltransferase mutation assay using mammalian V79 fibroblast cell line, extracts at 500 μg/mL neither induced mutations nor protected against the mutagenicity caused by methyl methanesulfonate (MMS). In the comet assay, none of the extracts revealed to be genotoxic by itself, and both afforded protection, more pronounced for larvae extracts, against MMS-induced genotoxicity. As genotoxic/antigenotoxic effects of Brassica vegetables are commonly attributed to isothiocyanates, the extracts were screened for these compounds by headspace-solid-phase microextraction/gas chromatography-mass spectrometry. No sulfur compound was detected. These findings demonstrate that both extracts could be useful against damage caused by genotoxic compounds, the larvae extract being the most promising.
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Affiliation(s)
- Carla Sousa
- REQUIMTE/Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, no. 228, 4050-313 Porto, Portugal
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Svensson JP, Fry RC, Wang E, Somoza LA, Samson LD. Identification of novel human damage response proteins targeted through yeast orthology. PLoS One 2012; 7:e37368. [PMID: 22615993 PMCID: PMC3353887 DOI: 10.1371/journal.pone.0037368] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 04/21/2012] [Indexed: 01/09/2023] Open
Abstract
Studies in Saccharomyces cerevisiae show that many proteins influence cellular survival upon exposure to DNA damaging agents. We hypothesized that human orthologs of these S. cerevisiae proteins would also be required for cellular survival after treatment with DNA damaging agents. For this purpose, human homologs of S. cerevisiae proteins were identified and mapped onto the human protein-protein interaction network. The resulting human network was highly modular and a series of selection rules were implemented to identify 45 candidates for human toxicity-modulating proteins. The corresponding transcripts were targeted by RNA interference in human cells. The cell lines with depleted target expression were challenged with three DNA damaging agents: the alkylating agents MMS and 4-NQO, and the oxidizing agent t-BuOOH. A comparison of the survival revealed that the majority (74%) of proteins conferred either sensitivity or resistance. The identified human toxicity-modulating proteins represent a variety of biological functions: autophagy, chromatin modifications, RNA and protein metabolism, and telomere maintenance. Further studies revealed that MMS-induced autophagy increase the survival of cells treated with DNA damaging agents. In summary, we show that damage recovery proteins in humans can be identified through homology to S. cerevisiae and that many of the same pathways are represented among the toxicity modulators.
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Affiliation(s)
- J. Peter Svensson
- Biological Engineering Department, Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Rebecca C. Fry
- Biological Engineering Department, Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Computation and Systems Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Emma Wang
- Biological Engineering Department, Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Luis A. Somoza
- Biological Engineering Department, Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Leona D. Samson
- Biological Engineering Department, Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Computation and Systems Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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Bazin E, Huet S, Jarry G, Le Hégarat L, Munday JS, Humpage AR, Fessard V. Cytotoxic and genotoxic effects of cylindrospermopsin in mice treated by gavage or intraperitoneal injection. Environ Toxicol 2012; 27:277-84. [PMID: 20725938 DOI: 10.1002/tox.20640] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2010] [Revised: 06/28/2010] [Accepted: 06/30/2010] [Indexed: 05/11/2023]
Abstract
Cylindrospermopsin (CYN), a cyanobacterial hepatotoxin mainly produced by Cylindrospermopsis raciborskii, has been involved in human intoxications and livestock deaths. The widespread occurrence of CYN in the water supplies lead us to investigate its genotoxicity to assess potential chronic effects. This study reports evaluation of CYN-induced in vivo DNA damage in mice using alkaline comet assay (ACA) and micronucleus assay (MNA) concomittantly. ACA measures DNA breakage from single and double strand breaks as well as alkali labile sites. Conversely, MNA detects chromosome damage events such as chromosomal breakage and numeric alterations. Male Swiss mice were treated with CYN concentrations of 50, 100, and 200 μg/kg by a single intraperitoneal (ip) injection or with 1, 2, and 4 mg/kg by gavage. Methyl methane sulfonate (MMS) was used as positive control at 80 mg/kg. Twenty-four hours after treatment, samples of liver, blood, bone marrow, kidney, intestine, and colon were taken to perform ACA, the bone marrow and the colon were also used for MNA. Parameters used to quantify DNA damage were % Tail DNA for ACA and both micronucleated immature erythrocytes and epithelial colon cells for MNA. DNA breaks and chromosome damage were significantly increased by MMS in all the organs evaluated. Significant DNA damage was detected within the colon by ACA after ip injection of 100 and 200 μg/kg CYN (P < 0.01). DNA damage was also detected in colon samples after 4 mg/kg oral administration of CYN and in bone marrow after 1 and 2 mg/kg of orally administered CYN. Histological examination showed foci of cell death within the liver and the kidney from mice that received the two highest doses of CYN by either route of administration.
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Affiliation(s)
- Emmanuelle Bazin
- Agence Française de Sécurité Sanitaire des Aliments, Unité de Toxicologie Génétique des Contaminants Alimentaires, BP 90 203, 35302 Fougères Cedex, France
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Rowe LA, Degtyareva N, Doetsch PW. Yap1: a DNA damage responder in Saccharomyces cerevisiae. Mech Ageing Dev 2012; 133:147-56. [PMID: 22433435 PMCID: PMC3351557 DOI: 10.1016/j.mad.2012.03.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 02/29/2012] [Accepted: 03/09/2012] [Indexed: 12/27/2022]
Abstract
Activation of signaling pathways in response to genotoxic stress is crucial for cells to properly repair DNA damage. In response to DNA damage, intracellular levels of reactive oxygen species increase. One important function of such a response could be to initiate signal transduction processes. We have employed the model eukaryote Saccharomyces cerevisiae to delineate DNA damage sensing mechanisms. We report a novel, unanticipated role for the transcription factor Yap1 as a DNA damage responder, providing direct evidence that reactive oxygen species are an important component of the DNA damage signaling process. Our findings reveal an epistatic link between Yap1 and the DNA base excision repair pathway. Corruption of the Yap1-mediated DNA damage response influences cell survival and genomic stability in response to exposure to genotoxic agents.
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Affiliation(s)
- Lori A. Rowe
- Department of Biochemistry, Emory University School of Medicine, Atlanta, USA, 30322
- Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University School of Medicine, Atlanta, USA, 30322
| | - Natalya Degtyareva
- Department of Biochemistry, Emory University School of Medicine, Atlanta, USA, 30322
- Emory Winship Cancer Institute, Emory University School of Medicine, Atlanta, USA, 30322
| | - Paul W. Doetsch
- Department of Biochemistry, Emory University School of Medicine, Atlanta, USA, 30322
- Emory Winship Cancer Institute, Emory University School of Medicine, Atlanta, USA, 30322
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, USA, 30322
- Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, USA, 30322
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Lacaze E, Geffard O, Goyet D, Bony S, Devaux A. Linking genotoxic responses in Gammarus fossarum germ cells with reproduction impairment, using the Comet assay. Environ Res 2011; 111:626-634. [PMID: 21489518 DOI: 10.1016/j.envres.2011.03.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 03/08/2011] [Accepted: 03/14/2011] [Indexed: 05/30/2023]
Abstract
Germ cells perform a unique and critical biological function: they pass down DNA that will be used for the development of the next generation. Thus there is an increasing need to understand how the adult exposure to genotoxicants could show negative impact on the offspring of aquatic organisms. Hence this work addresses the question of the consequences of germ cell DNA damage resulting from parental exposure on reproduction quality in the freshwater crustacean Gammarus fossarum, a high ecologically relevant species. Initially, the sensitivity response of mature oocytes and spermatozoa to two model genotoxicants, MMS and K(2)Cr(2)O(7) was compared by implementing the Comet assay after the exposure of these gammarids in the laboratory and after the exposure of caged organisms in the field. Spermatozoa appeared significantly more susceptible than the oocytes to genotoxicants whatever were the exposure conditions. Secondly, a significant correlation between the level of damage to the sperm DNA of exposed parents and the abnormality rate in embryos that had developed in non-contaminated water were demonstrated. Interestingly, this relationship bridges the biomarker response measured in germ cells at molecular level and its consequences at individual level for the subsequent generation. Moreover, reproduction defects were observed for a level of DNA damage exceeding a minimal threshold, which could have significant consequences for the population dynamics of this high ecologically relevant species.
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Affiliation(s)
- Emilie Lacaze
- Université de Lyon, INRA-ENTPE, Laboratoire des Sciences de l'Environnement, rue Maurice Audin, Vaulx en Velin, F-69518, France.
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Lukamowicz M, Woodward K, Kirsch-Volders M, Suter W, Elhajouji A. A flow cytometry based in vitro micronucleus assay in TK6 cells--validation using early stage pharmaceutical development compounds. Environ Mol Mutagen 2011; 52:363-372. [PMID: 20963789 DOI: 10.1002/em.20632] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 08/10/2010] [Accepted: 08/10/2010] [Indexed: 05/30/2023]
Abstract
The micronucleus test (MNT) is a well established test for detecting clastogenic and aneugenic compounds. Despite the assay's advantages, the MNT may produce false positive and false negative results in some conditions. This fact may be related to the underestimation of apoptosis or necrosis, the p53 status of the cell system or the cytotoxicity assay, and the top dose selection. The purpose of our studies was to contribute to the validation efforts of the flow cytometry based MNT. To identify the most reliable cytotoxicity assay for the top dose selection five parameters for relative survival were tested: relative cell count, relative population doubling, trypan blue supravital staining, relative ratio of scored nuclei to latex beads, and ethidium monoazide staining. For all compounds the least sensitive method was the relative cell count and the most reliable was the nuclei/beads ratio. The comparative evaluation of micronuclei induction in TK6 cells, analyzed with microscopy and flow cytometry, was performed with reference compounds and internal Novartis early development compounds with positive, weak positive, equivocal, and negative genotoxic effects. Our data document a good correlation between the MNT results obtained by flow cytometry and by microscopy. The results confirm that the method may be applied for routine testing in the pharmaceutical industry for the tested group of compounds, including compounds which require metabolic activation. However, further validation and miniaturization may be required.
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Affiliation(s)
- Magdalena Lukamowicz
- Novartis Institutes for Biomedical Research, Preclinical Safety, Genetic Toxicology and Safety Pharmacology, Basel, Switzerland.
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Ma W, Westmoreland JW, Gordenin DA, Resnick MA. Alkylation base damage is converted into repairable double-strand breaks and complex intermediates in G2 cells lacking AP endonuclease. PLoS Genet 2011; 7:e1002059. [PMID: 21552545 PMCID: PMC3084215 DOI: 10.1371/journal.pgen.1002059] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 03/02/2011] [Indexed: 11/20/2022] Open
Abstract
DNA double-strand breaks (DSBs) are potent sources of genome instability. While there is considerable genetic and molecular information about the disposition of direct DSBs and breaks that arise during replication, relatively little is known about DSBs derived during processing of single-strand lesions, especially for the case of single-strand breaks (SSBs) with 3′-blocked termini generated in vivo. Using our recently developed assay for detecting end-processing at random DSBs in budding yeast, we show that single-strand lesions produced by the alkylating agent methyl methanesulfonate (MMS) can generate DSBs in G2-arrested cells, i.e., S-phase independent. These derived DSBs were observed in apn1/2 endonuclease mutants and resulted from aborted base excision repair leading to 3′ blocked single-strand breaks following the creation of abasic (AP) sites. DSB formation was reduced by additional mutations that affect processing of AP sites including ntg1, ntg2, and, unexpectedly, ogg1, or by a lack of AP sites due to deletion of the MAG1 glycosylase gene. Similar to direct DSBs, the derived DSBs were subject to MRX (Mre11, Rad50, Xrs2)-determined resection and relied upon the recombinational repair genes RAD51, RAD52, as well as on the MCD1 cohesin gene, for repair. In addition, we identified a novel DNA intermediate, detected as slow-moving chromosomal DNA (SMD) in pulsed field electrophoresis gels shortly after MMS exposure in apn1/2 cells. The SMD requires nicked AP sites, but is independent of resection/recombination processes, suggesting that it is a novel structure generated during processing of 3′-blocked SSBs. Collectively, this study provides new insights into the potential consequences of alkylation base damage in vivo, including creation of novel structures as well as generation and repair of DSBs in nonreplicating cells. DNA double-strand breaks (DSBs) are an important source of genome instability that can lead to severe biological consequences including tumorigenesis and cell death. Although much is known about DSBs induced directly by ionizing radiation and radiomimetic cancer drugs, there is a relative dearth of information about the formation of derived DSBs that arise from processing of single-strand lesions. Since as many as 10,000–200,000 single-strand lesions have been estimated to occur each day in mammalian cells, conversion of even a small percentage of such lesions to DSBs could dramatically affect genome stability. Here we addressed the mechanism of formation and repair of derived DSBs in vivo during the processing of DNA methylation damage in yeast that are defective in base excision repair (BER) due to a lack of AP endonucleases. Armed with a technique developed in our lab that detects resection at DSBs, a first step in DSB repair, we demonstrated formation of DSBs in G2 cells and the role of recombinational repair in subsequent chromosome restitution. Furthermore, we have identified a novel repair intermediate that can be generated if abasic sites are nicked by AP lyases, providing additional insights into the processing of 3′-blocked groups at single-strand breaks.
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Affiliation(s)
- Wenjian Ma
- Chromosome Stability Group, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Jim W. Westmoreland
- Chromosome Stability Group, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Dmitry A. Gordenin
- Chromosome Stability Group, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Mike A. Resnick
- Chromosome Stability Group, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, Research Triangle Park, North Carolina, United States of America
- * E-mail:
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Luukkonen J, Liimatainen A, Höytö A, Juutilainen J, Naarala J. Pre-exposure to 50 Hz magnetic fields modifies menadione-induced genotoxic effects in human SH-SY5Y neuroblastoma cells. PLoS One 2011; 6:e18021. [PMID: 21448285 PMCID: PMC3063216 DOI: 10.1371/journal.pone.0018021] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 02/21/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Extremely low frequency (ELF) magnetic fields (MF) are generated by power lines and various electric appliances. They have been classified as possibly carcinogenic by the International Agency for Research on Cancer, but a mechanistic explanation for carcinogenic effects is lacking. A previous study in our laboratory showed that pre-exposure to ELF MF altered cancer-relevant cellular responses (cell cycle arrest, apoptosis) to menadione-induced DNA damage, but it did not include endpoints measuring actual genetic damage. In the present study, we examined whether pre-exposure to ELF MF affects chemically induced DNA damage level, DNA repair rate, or micronucleus frequency in human SH-SY5Y neuroblastoma cells. METHODOLOGY/PRINCIPAL FINDINGS Exposure to 50 Hz MF was conducted at 100 µT for 24 hours, followed by chemical exposure for 3 hours. The chemicals used for inducing DNA damage and subsequent micronucleus formation were menadione and methyl methanesulphonate (MMS). Pre-treatment with MF enhanced menadione-induced DNA damage, DNA repair rate, and micronucleus formation in human SH-SY5Y neuroblastoma cells. Although the results with MMS indicated similar effects, the differences were not statistically significant. No effects were observed after MF exposure alone. CONCLUSIONS The results confirm our previous findings showing that pre-exposure to MFs as low as 100 µT alters cellular responses to menadione, and show that increased genotoxicity results from such interaction. The present findings also indicate that complementary data at several chronological points may be critical for understanding the MF effects on DNA damage, repair, and post-repair integrity of the genome.
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Affiliation(s)
- Jukka Luukkonen
- Department of Environmental Science, University of Eastern Finland, Kuopio, Finland.
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National Toxicology Program. Methyl methanesulfonate. Rep Carcinog 2011; 12:268-9. [PMID: 21860482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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