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1.
Sci Total Environ ; 755(Pt 2): 143255, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33187710

RESUMO

The major weakness of the current in vitro genotoxicity test systems is the inability of the indicator cells to express metabolic enzymes needed for the activation and detoxification of genotoxic compounds, which consequently can lead to misleading results. Thus, there is a significant emphasis on developing hepatic cell models, including advanced in vitro three-dimensional (3D) cell-based systems, which better imitate in vivo cell behaviour and offer more accurate and predictive data for human exposures. In this study, we developed an approach for genotoxicity testing with 21-day old spheroids formed from human hepatocellular carcinoma cells (HepG2/C3A) using the dynamic clinostat bioreactor system (CelVivo BAM/bioreactor) under controlled conditions. The spheroids were exposed to indirect-acting genotoxic compounds, polycyclic aromatic hydrocarbon [PAH; benzo(a) pyrene B(a)P], and heterocyclic aromatic amine [PhIP]) at non-cytotoxic concentrations for 24 and 96 h. The results showed that both environmental pollutants B(a)P and PhIP significantly increased the level of DNA strand breaks assessed by the comet assay. Further, the mRNA level of selected genes encoding metabolic enzymes from phase I and II, and DNA damage responsive genes was determined (qPCR). The 21-day old spheroids showed higher basal expression of genes encoding metabolic enzymes compared to monolayer culture. In spheroids, B(a)P or PhIP induced compound-specific up-regulation of genes implicated in their metabolism, and deregulation of genes implicated in DNA damage and immediate-early response. The study demonstrated that this model utilizing HepG2/C3A spheroids grown under dynamic clinostat conditions represents a very sensitive and promising in vitro model for genotoxicity and environmental studies and can thus significantly contribute to a more reliable assessment of genotoxic activities of pure chemicals, and complex environmental samples even at very low for environmental exposure relevant concentrations.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Ensaio Cometa , Dano ao DNA , Humanos , Testes de Mutagenicidade , Mutagênicos/toxicidade
2.
Chemosphere ; 263: 128291, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297233

RESUMO

Approximately 20% industrial water pollution comes from textile dyeing process, with Azo dyes being a major problem in this scenario and requiring new forms of efficient treatment. Effluent treatments using the Advanced Oxidation Processes (AOP) are justified by the potential of application in the dyed effluent treatments once they can change the Azo dye chemical structure. Thus, this study aimed to evaluate the toxicity and mutagenic capacity of a synthetic effluent containing Amido Black 10B (AB10B) azo dye before treatment with AOP, named Gross Synthetic Effluent (GSE), and after the AOP, named Treated Synthetic Effluent (TSE). Daphnia magna and Allium cepa tests were used to evaluate acute toxicity effects and chromosomal mutagenesis, respectively. The Salmonella/microsome assay was performed to evaluate gene mutations. In silico assays were also performed aiming to identify the mutagenic and carcinogenic potential of the degradation byproducts of AB10B. There was 100% immobility to D. magna after 24 h and 48 h of treatments with TSE, showing EC50 values around 5%, whereas GSE did not show acute toxicity. However, GSE induced chromosomal mutations in A. cepa test. Both GSE and TSE were not able to induce gene mutations in S. typhimurium strains. These effects can be associated with two byproducts generated with the cleavage of the azo bonds of AB10B, 4-nitroaniline and -2-7-triamino-8-hydroxy-3-6-naphthalinedisulfate (TAHNDS). In conclusion, AOP is an efficient method to reduce the mutagenicity of synthetic effluent containing AB10B and additional methods should be applied aiming to reduce the toxicity.


Assuntos
Mutagênicos , Poluentes Químicos da Água , Animais , Compostos Azo/toxicidade , Corantes/toxicidade , Daphnia , Mutagênese , Testes de Mutagenicidade , Mutagênicos/análise , Mutagênicos/toxicidade , Indústria Têxtil , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
3.
Sci Total Environ ; 751: 142269, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-33182016

RESUMO

This study presents a high-throughput (HTP) micronucleus assay in multi-well plates with an automated evaluation for risk assessment applications. The evaluation of genotoxicity via the micronucleus assays according to international guidelines ISO 21427-2 with Chinese hamster (Cricetulus griseus) V79 cells was the starting point to develop our methodology. A drawback of this assay is that it is very time consuming and cost intensive. Our HTP micronucleus assay in a 48-well plate format allows for the simultaneous assessment of five different sample-concentrations with additional positive, negative and solvent controls with six technical replicates each within a quarter of the time required for the equivalent evaluation using the traditional slide method. In accordance with the 3R principle, animal compounds should be replaced with animal-free alternatives. However, traditional cell culture-based methods still require animal derived compounds like rat-liver derived S9-fraction, which is used to simulate the mammalian metabolism in in vitro assays that do show intrinsic metabolization capabilities. In the present study, a recently developed animal-free biotechnological alternative (ewoS9R) was investigated in the new high-throughput micronucleus assay. In total, 12 different mutagenic or genotoxic chemicals were investigated to assess the potential use of the animal-free metabolization system (ewoS9R) in comparison to a common rat-derived product. Out of the 12 compounds, one compound did not induce micronuclei in any treatment and 2 substances showed a genotoxic potential without the need for a metabolization system. EwoS9R demonstrated promising potential for future applications as it shows comparable results to the rat-derived S9 for 6 of the 9 pro-genotoxic substances tested. The remaining 3 substances (2-Acetamidofluorene, Benzo[a]pyrene, Cyclophosphamide) were only metabolized by rat-derived S9. A potential explanation is that ewoS9R was investigated with an approx. 10-fold lower enzyme concentration and was only optimized for CYP1A metabolization that may be improved with a modified production procedure. Future applications of ewoS9R go beyond the micronucleus assay, but further research is necessary.


Assuntos
Benzo(a)pireno , Mutagênicos , Animais , Linhagem Celular , Cricetinae , Ciclofosfamida , Testes para Micronúcleos , Mutagênicos/toxicidade , Ratos
4.
Sci Total Environ ; 752: 141937, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33207528

RESUMO

The increased contamination of surface water with plastic waste is proportional to the increased consumption of products that use them as raw material. However, the impact of these residues on aquatic biota remains limited, mainly when it comes to nanoplastics (NPs). Thus, the aim of the current study is to test the hypothesis that the exposure of Ctenopharyngodon idella juveniles to polystyrene nanoplastics (PS NPs) at low concentrations (0.04 ng/L, 34 ng/L and 34 µg/L), for 20 days, leads to DNA damage and has mutagenic and cytotoxic effects on their erythrocytes. Comet assay enabled observing that DNA damage (inferred from the greater tail length, DNA percentage in the tail and Olive tail moment) induced by PS NPs has increased as the pollutant concentrations have increased, as well as that the formation of micronuclei and other nuclear abnormalities was equitable in animals exposed to this pollutant. On the other hand, there were significant changes in erythrocyte shape and size, oxidative stress generation (NO levels, lipid peroxidation, hydrogen peroxide), antioxidant system inhibition (mediated by total hepatic glutathione) and PS NPs accumulation in the liver and brain of animals exposed to higher concentrations of it. Therefore, the current study has confirmed the initial hypothesis and enhanced the knowledge about the genotoxic, mutagenic and cytotoxic potential of PS NPs in freshwater fish at early developmental stage, relating these effects to biochemical changes and significant accumulation of these nanomaterials. Besides, it is a warning about the (eco) toxicological risk represented by these nanopollutants in aquatic environments. CAPSULE: Polystyrene nanoplastics are capable of inducing DNA damage, mutagenic and cytotoxicity changes in fish.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Animais , Dano ao DNA , Microplásticos , Mutagênicos/toxicidade , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade
5.
Sci Total Environ ; 759: 143522, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33246726

RESUMO

Metabolism has to be considered during the toxicological assessment of chemical and environmental samples because it is an important process in the mammalian liver. It can be assessed in vitro via liver homogenates called S9-fractions, an external metabolic activation system. However, the external metabolic activation systems can vary greatly in their composition due to biological variations among individual animals and animal strains that the S9-fraction are derived as well as the differences in the production treatment. To gain more insight into these variances, three different but commonly used rat-derived S9-fractions were compared in the present study for their variance and performance with a reference compound in the Ames fluctuation assay with Salmonella typhimurium strains TA 98 and TA 100 according to ISO 11350. Severe shortcomings of conventional rat-derived S9-fractions were observed in the present study, such that S9-fractions differed significantly within the same rat strain and for different types of induction procedures in regards to the metabolic capability. An intrinsic mutagenic potential of the three rat-derived S9-fractions were identified in the Ames fluctuation assay with varying S9-fraction concentrations. To address some of the shortcomings of the animal-derived S9-fraction, the present study investigated the use and performance of a biotechnological, animal-free alternative, ewoS9R, in comparison to one of the rat-derived S9-fraction as the others showed a mutagenic potential themselves. Specifically, 12 different chemicals were used as a reference to determine if ewoS9R could serve as an adequate and more consistent replacement of traditional rat-derived metabolic activation systems: 8 pro-mutagenic compounds (i.e., require metabolic activation to show a mutagenic potential), one pro-mutagenic compound but not in the tested strains, one mutagenic compound without metabolic activation and two compounds that are equivocal in the literature. EwoS9R was evaluated as a promising approach in the Ames fluctuation assay with 5 compounds observed to have similar results with both rat-derived S9-fraction and ewoS9R (41%), for 3 compounds ewoS9R was a better metabolization system than the rat-derived S9-fraction (16%). Further research is necessary to determine the full potential of ewoS9R in comparison to rat-derived S9-fractions.


Assuntos
Fígado , Mutagênicos , Animais , Biotransformação , Fígado/metabolismo , Microssomos Hepáticos/metabolismo , Testes de Mutagenicidade , Ratos
6.
J Water Health ; 18(6): 1124-1138, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33328381

RESUMO

Jordan is one of the lowest countries in the world in terms of water resources. The reuse of treated wastewater is an important alternative to supply agricultural demands for water. In Jordan, Kherbet Al-Samra wastewater treatment plant (KSWWTP) is the largest and its effluent is mainly used for irrigation purposes. In this study, bacterial contamination and mutagenic potential were evaluated in six sites, beginning with KSWWTP and ending with King Tallal Dam. The results showed high contamination with many pathogenic bacteria and coliforms. The isolated pathogenic bacteria were Salmonella sp., Shigella sp., Bacillus cereus and Staphylococcus aureus. The isolated opportunistic pathogenic bacteria were Acinetobacter lwoffii, Elizabethkingia meningosepticum, Pseudomonas fluorescens and Bacillus licheniformis. These bacteria were found in all sampling sites without a specific prevalence pattern. Differences in temperature between seasons affect total coliform and other bacterial count. All water samples showed positive mutagenic activity and high bacterial pollution. Improving the disinfection efficiency in the wastewater treatment plant is important to minimize potential toxicity and exposure of public health to pathogenic bacteria, reduce water resources' contamination and environmental pollution. Increasing effluent sampling frequency from KSWWTP is required to monitor bacterial contamination and toxicity/mutagenicity level for water safety and public health risk assessments.


Assuntos
Águas Residuárias , Purificação da Água , Acinetobacter , Jordânia , Mutagênicos , Eliminação de Resíduos Líquidos , Microbiologia da Água
7.
Phys Chem Chem Phys ; 22(48): 28115-28122, 2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33290476

RESUMO

Repurposed drugs are now considered as attractive therapeutics against COVID-19. It is shown that Remdesivir, a nucleoside drug that was originally invented for the Ebola virus, is effective in suppressing the replication of SARS-CoV-2 that causes COVID-19. Similarly, Galidesivir, Favipiravir, Ribavirin, N4-hydroxycytidine (EIDD-1931), and EIDD-2801 (a prodrug of EIDD-1931) were also found to be effective against COVID-19. However, the mechanisms of action of these drugs are not yet fully understood. For example, in some experimental studies, these drugs were proposed to act as a RNA-chain terminator, while in other studies, these were proposed to induce base-pair mutations above the error catastrophe limit to stall the replication of the viral RNA. To understand the mutagenic effects of these drugs, the role of different tautomers in their base-pairing abilities is studied here in detail by employing a reliable dispersion-corrected density functional theoretic method. It is found that Remdesivir and Galidesivir can adopt both amino and imino tautomeric conformations to base-pair with RNA bases. While the insertions of G and U are preferred against the amino tautomers of these drugs, the insertion of C is mainly possible against the imino tautomers. However, although Favipiravir and Ribavirin can make stable base pair interactions by using their keto and enol tautomers, the formation of the latter pairs would be less probable due to the endothermic nature of the products. Interestingly, the insertions of all of the RNA bases are found to be possible against the keto tautomer of Favipiravir, while the keto tautomer of Ribavirin has a clear preference for G. Remarkably, due to the negligible difference in the stability of EIDD-2801 and EIDD-1931, these tautomers would coexist in the biological environment. The insertion of G is found to be preferred against EIDD-1931 and the incorporations of U, A, and G are preferred opposite EIDD-2801. These findings suggest that base-pair mutations are the main causes of the antiviral properties of these drugs.


Assuntos
Antivirais/química , Pareamento de Bases , Mutagênicos/química , Nucleosídeos/química , RNA/química , /tratamento farmacológico , Teoria da Densidade Funcional , Isomerismo , Modelos Químicos , Termodinâmica
8.
Int J Nanomedicine ; 15: 9025-9047, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33235450

RESUMO

Background: Linalool is a monoterpene compound with various potential therapeutic applications in several medical fields. Previous studies have indicated the activity of linalool against cell lines; however, its high level of toxicity restricts its use. The aim of this study was to design and manufacture compounds with a novel structure that can be used for loading linalool, to reduce its toxicity and improve its reachable ability. Methods: We synthesized and characterized a new molecule for loading linalool onto gold nanoparticles (GNPs) capped with glutathione and conjugated with a CALNN peptide. Linalool was loaded onto the GNPs via the reaction of the surface groups of both linalool and the GNPs. Moreover, the target peptide could be loaded onto the surface of the GNPs via a chemical reaction. The cytotoxic effects of linalool-GNP (LG) and linalool-GNP-CALNN peptide (LGC) conjugates against ovarian cancer cells were investigated, as were the possible mechanisms underlying the induction of apoptosis. Results: Our findings illustrated the significant antiproliferative effect of LG and LGC on SKOV-3 cells. The cytotoxicity assay demonstrated that LG and LGC were selectively toxic in cancer cells and induced apoptosis by activating caspase-8, the p53 protein, and various proteins involved in apoptosis. The present data demonstrated that LG and LGC have a high therapeutic potential and should be given particular consideration as anticancer drug-delivery systems, as LG and LGC were remarkably more cytotoxic against a cancer cell line than were linalool and GNPs alone. Conclusion: We concluded that LG and LGC are promising compounds that can be used for treating ovarian cancer (SKOV-3) cells via the induction of apoptosis through extrinsic and intrinsic pathways.


Assuntos
Monoterpenos Acíclicos/química , Apoptose , Glutationa/química , Ouro/química , Nanopartículas Metálicas/química , NF-kappa B/metabolismo , Peptídeos/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Biomarcadores Tumorais/metabolismo , Caspase 8/genética , Caspase 8/metabolismo , Linhagem Celular Tumoral , Forma do Núcleo Celular/efeitos dos fármacos , Dano ao DNA , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Nanopartículas Metálicas/ultraestrutura , Mutagênicos/toxicidade , Transporte Proteico/efeitos dos fármacos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética
9.
Toxicol Appl Pharmacol ; 409: 115303, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33141059

RESUMO

DNA damage plays a crucial role in the transforming potential of the human carcinogen arsenic. The arsenic biotransformation enzyme AS3MT is known to participate in the generation of ROS after arsenic exposure, whereas MTH1 sanitizes oxidized dNTP pools to prevent the incorporation of damaged bases into DNA. In this work, we sought to assess the role of these two enzymes in the genotoxic and carcinogenic effects of arsenic exposure. Thus, mouse embryonic fibroblasts (MEF), transformed by chronic arsenite exposure, were monitored for DNA damage by the comet and the micronucleus assays at different time-of-exposure intervals lasting for 50 weeks. Results indicate that the oxidative and DNA damage of chronically exposed MEF cells increased time-dependently up to the point of transformation. As3mt expression followed a pattern like that of DNA damage, and its forced inhibition by shRNA technology before transformation resulted in a DNA damage decrease. On the other hand, Mth1 mRNA levels increased after the transformation point, and its forced knock-down increased significantly the levels of DNA damage and decreased the aggressiveness of the oncogenic phenotype. Thus, As3mt and Mth1 have important differential roles in the accumulation of DNA damage linked to the transformation process: while As3mt contributes to the genotoxic effects before the transformation, Mth1 prevents the DNA damage fixation after the acquisition of the oncogenic phenotype. This study demonstrates the influence of As3mt and Mth1 in arsenic DNA damage induction and it is the first to present Mth1 as a candidate modulator biomarker of the tumoral phenotype.


Assuntos
Arsênico/toxicidade , Carcinogênese/efeitos dos fármacos , Carcinógenos/toxicidade , Metiltransferases/metabolismo , Mutagênicos/toxicidade , Monoéster Fosfórico Hidrolases/metabolismo , Animais , Arsenitos/efeitos adversos , Carcinogênese/metabolismo , Linhagem Celular , Células Cultivadas , Dano ao DNA/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Camundongos , Testes para Micronúcleos/métodos , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Fenótipo , RNA Mensageiro/metabolismo
11.
Nat Genet ; 52(11): 1139-1143, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33106632

RESUMO

Cancer is driven by genomic mutations in 'cancer driver' genes, which have essential roles in tumor development. These mutations may be caused by exposure to mutagens in the environment or by endogenous DNA-replication errors in tissue stem cells. Recent observations of abundant mutations, including cancer driver mutations, in histologically normal human tissues suggest that mutations alone are not sufficient for tumor development, thus prompting the question of how single mutant cells give rise to neoplasia. In a concept supported by decades-old data from mouse tumor models, non-mutagenic tumor-promoting agents have been posited to activate the proliferation of dormant mutated cells, thus generating actively growing lesions, with the promotion stage as the rate-limiting step in tumor formation. Non-mutagenic promoting agents, either endogenous or environmental, may therefore have a more important role in human cancer etiology than previously thought.


Assuntos
Poluentes Ambientais/toxicidade , Mutagênicos/toxicidade , Neoplasias/etiologia , Animais , Transformação Celular Neoplásica , Humanos , Camundongos , Mutação , Neoplasias/induzido quimicamente , Neoplasias/genética , Neoplasias Experimentais , Fatores de Risco , Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/genética
12.
Exp Parasitol ; 219: 108016, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33035543

RESUMO

Different genotoxic agents can lead to DNA single- and double-strand breaks, base modification and oxidation. As most living organisms, Trypanosoma cruzi is subjected to oxidative stress during its life cycle; thus, DNA repair is essential for parasite survival and establishment of infection. The mitochondrion plays important roles beyond the production of ATP. For example, it is a source of signaling molecules, such as the superoxide anion and H2O2. Since T. cruzi has only one mitochondrion, the integrity of this organelle is pivotal for parasite viability. H2O2 and methyl methanesulfonate cause DNA lesions in T. cruzi that are repaired by different DNA repair pathways. Herein, we evaluate mitochondrial involvement during the repair of nuclear and mitochondrial DNA in T. cruzi epimastigotes incubated with these two genotoxic agents under conditions that induce repairable DNA damage. Overall, in both treatments, an increase in oxygen consumption rates and in mitochondrial H2O2 release was observed, as well as maintenance of ATP levels compared to control. Interestingly, these changes coincided with DNA repair kinetics, suggesting the importance of the mitochondrion for this energy-consuming process.


Assuntos
Reparo do DNA/fisiologia , DNA Mitocondrial/fisiologia , Mitocôndrias/fisiologia , Trypanosoma cruzi/fisiologia , Trifosfato de Adenosina/metabolismo , Núcleo Celular/genética , Núcleo Celular/fisiologia , Dano ao DNA , Reparo de Erro de Pareamento de DNA/fisiologia , Peróxido de Hidrogênio/metabolismo , Cinética , Metanossulfonato de Metila/farmacologia , Mutagênicos/farmacologia , Fosforilação Oxidativa , Estresse Oxidativo , Consumo de Oxigênio/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/genética
13.
Science ; 370(6512): 75-82, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33004514

RESUMO

The extent of somatic mutation and clonal selection in the human bladder remains unknown. We sequenced 2097 bladder microbiopsies from 20 individuals using targeted (n = 1914 microbiopsies), whole-exome (n = 655), and whole-genome (n = 88) sequencing. We found widespread positive selection in 17 genes. Chromatin remodeling genes were frequently mutated, whereas mutations were absent in several major bladder cancer genes. There was extensive interindividual variation in selection, with different driver genes dominating the clonal landscape across individuals. Mutational signatures were heterogeneous across clones and individuals, which suggests differential exposure to mutagens in the urine. Evidence of APOBEC mutagenesis was found in 22% of the microbiopsies. Sequencing multiple microbiopsies from five patients with bladder cancer enabled comparisons with cancer-free individuals and across histological features. This study reveals a rich landscape of mutational processes and selection in normal urothelium with large heterogeneity across clones and individuals.


Assuntos
Genes Neoplásicos , Mutagênese , Seleção Genética , Neoplasias da Bexiga Urinária/genética , Bexiga Urinária/patologia , Urotélio/patologia , Desaminases APOBEC/genética , Adulto , Idoso , Biópsia , Montagem e Desmontagem da Cromatina/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutagênicos/análise , Mutação
14.
Science ; 370(6512): 82-89, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33004515

RESUMO

Knowledge of somatic mutation accumulation in normal cells, which is essential for understanding cancer development and evolution, remains largely lacking. In this study, we investigated somatic clonal events in morphologically normal human urothelium (MNU; epithelium lining the bladder and ureter) and identified macroscopic clonal expansions. Aristolochic acid (AA), a natural herb-derived compound, was a major mutagenic driving factor in MNU. AA drastically accelerates mutation accumulation and enhances clonal expansion. Mutations in MNU were widely observed in chromatin remodeling genes such as KMT2D and KDM6A but rarely in TP53, PIK3CA, and FGFR3 KMT2D mutations were found to be common in urothelial cells, regardless of whether the cells experience exogenous mutagen exposure. Copy number alterations were rare and largely confined to small-scale regions, along with copy-neutral loss of heterozygosity. Single AA-associated clones in MNU expanded to a scale of several square centimeters in size.


Assuntos
Ácidos Aristolóquicos/toxicidade , Montagem e Desmontagem da Cromatina/genética , Mutagênicos/toxicidade , Neoplasias da Bexiga Urinária/induzido quimicamente , Neoplasias da Bexiga Urinária/genética , Urotélio/efeitos dos fármacos , Urotélio/patologia , Classe I de Fosfatidilinositol 3-Quinases/genética , Proteínas de Ligação a DNA/genética , Histona Desmetilases/genética , Humanos , Mutagênese , Mutação , Proteínas de Neoplasias/genética , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/genética , Proteína Supressora de Tumor p53/genética
15.
Artigo em Inglês | MEDLINE | ID: mdl-33043805

RESUMO

The influence of the UV-Vis radiation on the toxicity of agomelatine, loxapine, clozapine and tiapride was studied. The phototransformation procedure was conducted with the use of simulated solar radiation. In the case of each compound irradiation time necessary to decompose half of the initial concentration was chosen. The embryotoxicity and acute toxicity were evaluated using zebrafish (Danio rerio) embryos and larvae. The mutagenicity assay was done with the use of a micro-plate Ames test. Generally, the embryotoxicity decreased after the irradiation procedure. The obtained results showed that tiapride is the least toxic compound to zebrafish, however, its toxicity toward larvae increases after the irradiation. Similarly, the mutagenic potential of the mixture of tiapride photoproducts is higher than in the case of parent compound. The phototransformation of loxapine resulted in the change of the acute toxicity profile and increased the rate of reverse mutations in the Ames test. Oppositely, the irradiation of agomelatine caused the decrease of mutagenic potential and acute toxicity was also lower in the postirradiated mixture. The phototransformation of clozapine did not alter the mutagenicity and decreased the acute toxicity to the zebrafish larvae. In silico calculations showed a satisfactory prediction ability in some instances, especially in the case of mutagenic potential of the tiapride phototransformation products.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Mutagênicos/toxicidade , Psicotrópicos/toxicidade , Raios Ultravioleta , Peixe-Zebra/genética , Animais , Desenvolvimento Embrionário/genética , Larva/genética , Testes de Mutagenicidade , Mutagênicos/efeitos da radiação , Psicotrópicos/efeitos da radiação , Testes de Toxicidade Aguda , Peixe-Zebra/crescimento & desenvolvimento
16.
Chem Res Toxicol ; 33(10): 2668-2674, 2020 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-32894672

RESUMO

Inflammation is an immune response to protect against various types of infections. When unchecked, acute inflammation can be life-threatening, as seen with the current coronavirus pandemic. Strong oxidants, such as peroxynitrite produced by immune cells, are major mediators of the inflammation-associated pathogenesis. Cellular thiols play important roles in mitigating inflammation-associated macromolecular damage including DNA. Herein, we have demonstrated a role of glutathione (GSH) and other thiols in neutralizing the effect of peroxynitrite-mediated DNA damage through stable GSH-DNA adduct formation. Our observation supports the use of thiol supplements as a potential therapeutic strategy against severe COVID-19 cases and a Phase II (NCT04374461) open-label clinical trial launched in early May 2020 by the Memorial Sloan Kettering Cancer Center.


Assuntos
Adutos de DNA/efeitos dos fármacos , DNA/efeitos dos fármacos , Glutationa/farmacologia , Inflamação/fisiopatologia , Ácido Peroxinitroso/efeitos adversos , Doença Aguda , Animais , Betacoronavirus , Bovinos , Infecções por Coronavirus/tratamento farmacológico , DNA/química , Adutos de DNA/química , Dano ao DNA , Glutationa/química , Células HEK293 , Humanos , Mutagênicos/química , Mutagênicos/farmacologia , Pandemias , Ácido Peroxinitroso/química , Pneumonia Viral/tratamento farmacológico , Salmonella typhimurium/genética
17.
Water Res ; 186: 116328, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32866931

RESUMO

Aim of this study was to investigate the impact of advanced wastewater treatment techniques (combining ozonation with activated carbon filtration) on acute and genotoxic activities of tertiary treated wastewater. Concentrated samples were tested in Salmonella/microsome assays. Furthermore, induction of DNA damage was measured in liver-derived cells (human hepatoma and primary rat hepatocytes) in single cell gel electrophoresis experiments, which are based on the measurement of DNA migration in an electric field. These cell types possess phase I and phase II enzymes, which catalyze the activation/detoxification of mutagens. Acute toxicity was determined with the trypan blue exclusion technique. We found no evidence for mutagenic effects of non-ozonated samples in several bacterial tester strains (TA98, TA100, YG7108, YG7104, YG7112 and YG7113) but clear induction of His+ mutants after O3 treatment in two strains with defective genes encoding for DNA repair, which are highly sensitive towards alkylating agents (YG7108 and YG7104). These effects were reduced after activated carbon filtration. Furthermore, we detected a slight increase of mutagenic activity in strain YG1024 with increased acetyltransferase activity, which is sensitive towards aromatic amines and nitro compounds in untreated water, which was not reduced by O3 treatment. A completely different pattern of mutagenic activity was seen in liver-derived cells; non ozonated samples caused in both cell types pronounced DNA damage, which was reduced (by ca. 25%) after ozonation. Activated carbon treatment did not cause a substantial further reduction of DNA damage. Additional experiments with liver homogenate indicate that the compounds which cause the effects in the human cells are promutagens which require enzymatic activation. None of the waters caused acute toxicity in the liver-derived cells and in the bacterial indicators. Assuming that hepatic mammalian cells reflect the genotoxic properties of the waters in vertebrates (including humans) more adequately as genetically modified bacterial indicators, we conclude that ozonation has beneficial effects in regard to the reduction of genotoxic properties of treated wastewaters.


Assuntos
Ozônio , Águas Residuárias , Animais , Carvão Vegetal , Dano ao DNA , Hepatócitos , Humanos , Fígado , Testes de Mutagenicidade , Mutagênicos/toxicidade , Ratos
18.
Mutat Res ; 856-857: 503217, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32928365

RESUMO

We studied the genotoxicity and cellular uptake of nanosized (<50 nm) and fine (<10 µm) copper oxide (CuO) particles in vitro in human bronchial epithelial (BEAS-2B) cells. In addition, the effect of dispersing the particles using bovine serum albumin (BSA) on DNA damage induction was investigated. DNA damage was assessed by the alkaline comet (single cell gel electrophoresis) assay after 3-h, 6-h and 24-h exposures. The cytokinesis-block micronucleus assay was applied to study chromosome damage. Both fine- and nanosized CuO particles induced a dose-dependent increase in DNA damage at all timepoints tested. However, nanosized CuO damaged DNA at lower doses and higher levels compared with fine CuO. Dispersing the nanoparticles in the presence of BSA (0.6 mg/mL) resulted in a small and inconsistent decrease in DNA damage compared with dispersions in serum-free cell culture medium only. CuO nanoparticles induced a clear dose-dependent increase in micronucleated cells at doses that strongly increased cytostasis and were markedly cytotoxic at 24 and 48 h. Fine CuO showed a slight induction of micronuclei. Hyperspectral microscopy indicated a substantial cellular uptake of both types of particles after a 3-h exposure to a dose of 20 µg/cm2. The number of particles internalized by the cells was higher for nanosized than fine CuO, as quantified by the frequency of spectral matches in the total cell area and by the number of spectrally matched visible particles or agglomerates per cell. The particle uptake was limited by particle size. The stronger genotoxic activity of nanosized than fine CuO particles is likely to derive from the higher cellular uptake and more effective intracellular dissolution of nanoparticles.


Assuntos
Brônquios/efeitos dos fármacos , Cobre/farmacologia , Dano ao DNA/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cobre/química , Humanos , Nanopartículas Metálicas/química , Mutagênicos/química , Mutagênicos/farmacologia , Tamanho da Partícula , Análise de Célula Única
19.
Mutat Res ; 856-857: 503218, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32928366

RESUMO

The Ames microplate format (MPF™) is a miniaturized version of the plate agar Ames tests that takes advantage of a liquid microplate approach in 384-well plates with a color change-based readout. This method, already compared to the Ames test in Petri dishes, is used to assess the genotoxic potential of a variety of test items, including (but not limited to) chemicals, environmental samples, and drug candidates. 61 chemicals were selected from the updated recommended lists of genotoxic and non-genotoxic chemicals for assessment of the performance of new or improved genotoxicity tests and tested in up to five bacterial strains. The agreement with the data from the scientific literature (over 90%) confirms the reliability of the Ames MPF™ as a cost-effective and 3R-compliant alternative to the regulatory Ames test that allows to predict and evaluate chemicals' mutagenicity in a faster, less laborious and, if available, automatable manner.


Assuntos
Carcinógenos/farmacologia , Dano ao DNA/efeitos dos fármacos , Testes de Mutagenicidade/métodos , Mutagênicos/farmacologia , Carcinógenos/toxicidade , Escherichia coli/efeitos dos fármacos , Humanos , Microfluídica/métodos , Mutagênicos/toxicidade , Reprodutibilidade dos Testes
20.
Mutat Res ; 856-857: 503231, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32928371

RESUMO

Heavy metals are widely used in many industries in Thailand and found in the environment. Occupational exposure to heavy metals is often chronic and caused by environmental contaminations, potentially leading to mutations and cancer. Although the genotoxic effects of occupational exposure to multiple heavy metals have been extensively studied, the findings regarding their genotoxicity are conflicting. In this study, we focused on investigating the genotoxic effects of certain heavy metals mixtures, including lead (Pb), copper (Cu), zinc (Zn), and tin (Sn), to which workers are exposed in the manufacturing industry. The cytokinesis-blocked micronucleus (CBMN) assay in peripheral blood lymphocytes was performed, and DNA damage was assessed by measuring tumour-associated protein levels and 8-hydroxy-2'-deoxyguanosine (8-OHdG) generated by oxidative stress that causes cytotoxicity. The occupational exposure group included 110 workers exposed to heavy metal mixtures and 105 matched control subjects. We found statistically significant differences in the blood Pb, Sn, and Cu levels between the exposed workers and the control subjects (p < 0.001). Analysis of micronuclei (MN) in peripheral blood lymphocytes revealed a significantly increased frequency of MN in exposed workers compared with that in control subjects (p<0.05). Non-smoking exposed workers were selected for 8-OHdG formation and mutant p53 tests, and significant differences in the mean plasma 8-OHdG concentration (p < 0.001) were found between the occupational exposure and the control group, but no differences were found in the levels of mutant p53. Thus, chronic exposure to different heavy metals causes genotoxic effects in humans. Furthermore, the CBMN assay and 8-OHdG formation can be used as surrogate biomarkers to identify and monitor groups with higher carcinogenic risk in the early stages of toxicity. In summary, our results indicate that mixtures of heavy metals (Pb, Sn, and Cu) in manufacturing industries pose an elevated health risk due to DNA damage.


Assuntos
Dano ao DNA/efeitos dos fármacos , Metais Pesados/toxicidade , Mutagênese/efeitos dos fármacos , Mutagênicos/toxicidade , Exposição Ocupacional/efeitos adversos , Adulto , Cobre/farmacologia , Cobre/toxicidade , Citocinese/efeitos dos fármacos , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Chumbo/farmacologia , Chumbo/toxicidade , Linfócitos/efeitos dos fármacos , Linfócitos/patologia , Masculino , Indústria Manufatureira , Metais Pesados/farmacologia , Testes para Micronúcleos , Pessoa de Meia-Idade , Mutagênicos/farmacologia , Proteína Supressora de Tumor p53
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