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1.
Mutat Res ; 850-851: 503136, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32247553

RESUMO

Tumorigenesis induced by oxidative stress is thought to be initiated by mutagenesis, but via an indirect mechanism. The dose-response curves for agents that act by this route usually show a threshold, for unknown reasons. To gain insight into these phenomena, we have analyzed the dose response for mutagenesis induced by the oral administration of potassium bromate, a typical oxidative-stress-generating agent, to gpt delta mice. The agent was given orally for 90 d to either Nrf2+ or Nrf2-knockout (KO) mice and mutants induced in the small intestine were analyzed. In Nrf2+mice, the mutant frequency was significantly greater than in the vehicle controls at a dose of 0.6 g/L but not at 0.2 g/L, indicating that a practical threshold for mutagenesis lies between these doses. At 0.6 g/L, the frequencies of G-to-T transversions (landmark mutations for oxidative stress) and G-to-A transitions were significantly elevated. In Nrf2-KO mice, too, the total mutant frequency was increased only at 0.6 g/L. G-to-T transversions are likely to have driven tumorigenesis in the small intestine. A site-specific G-to-T transversion at guanine (nucleotide 406) in a 5'-TGAA-3' sequence in gpt, and our primer extension reaction showed that formation of the oxidative DNA base modification 8-oxo-deoxyguanosine (8-oxo-dG) at nucleotide 406 was significantly increased at doses of 0.6 and 2 g/L in the gpt delta mice. In the Apc oncogene, guanine residues in the same or similar sequences (TGAA or AGAA) are highly substituted by thymine (G-to-T transversions) in potassium bromate-induced tumors. We propose that formation of 8-oxo-dG in the T(A)GAA sequence is an initiating event in tumor formation in the small intestine in response to oxidative stress.


Assuntos
Bromatos/toxicidade , Mutagênese/genética , Estresse Oxidativo/genética , Pentosiltransferases/genética , 8-Hidroxi-2'-Desoxiguanosina/genética , Administração Oral , Animais , Bromatos/farmacologia , Carcinogênese/efeitos dos fármacos , Carcinogênese/genética , DNA/efeitos dos fármacos , DNA/genética , Relação Dose-Resposta a Droga , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/patologia , Camundongos , Camundongos Knockout , Mutagênese/efeitos dos fármacos , Mutação , Fator 2 Relacionado a NF-E2/genética , Estresse Oxidativo/efeitos dos fármacos
2.
Anticancer Res ; 40(4): 2025-2032, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32234893

RESUMO

BACKGROUND/AIM: The winemaking procedure results in the generation of stems, a by-product that is harmful to the environment. Concomitantly, stems are rich in polyphenols and, hence, they are putatively beneficial for human health. MATERIALS AND METHODS: In this study, the grape stem extracts derived from three native Greek vine varieties, namely Mavrodaphne, Muscat and Rhoditis were examined for their chemical composition and antioxidant and antimutagenic properties using a battery of in vitro biomarkers. RESULTS: All extracts are rich in polyphenols. Moreover, they exhibit potent antioxidant and antimutagenic properties with the extract of Mavrodaphne being the strongest in reducing the DPPH• and O2 -• radicals and the Fe3+ and in protecting plasmid DNA from peroxyl radical-induced oxidative modification. CONCLUSION: Therefore, although they are serious pollutants, grape stems contain phytochemicals with important biological properties and can be used as (ingredients of) bio-functional foods to improve certain aspects of human health.


Assuntos
Antioxidantes/farmacologia , DNA/efeitos dos fármacos , Polifenóis/farmacologia , Vitis/química , DNA/metabolismo , Dano ao DNA/efeitos dos fármacos , Grécia , Humanos , Oxirredução , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Caules de Planta/química , Plasmídeos/efeitos dos fármacos , Plasmídeos/metabolismo , Polifenóis/química , Espécies Reativas de Oxigênio/metabolismo
3.
PLoS One ; 15(1): e0221681, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31923208

RESUMO

DNA repair inhibition has been described as an essential event leading to the initiation of carcinogenesis. In a previous study, we observed that the exposure to metal mixture induces changes in the miR-nome of the cells that was correlated with the sub-expression of mRNA involved in processes and diseases associated with metal exposure. From this analysis, one of the miRNAs that shows changes in its expression is miR-222, which is overexpressed in various cancers associated with exposure to metals. In silico studies showed that a possible target for the microRNA-222 could be Rad 51c, a gene involved in the double-stranded DNA repair. We could appreciate that up-regulation of miR-222 reduces the expression both gene and as a protein expression of Rad51c by RT-PCR and immunoblot, respectively. A luciferase assay was performed to validate Rad51c as miR-222 target. Neutral comet assay was performed in order to evaluate DNA double-strand breaks under experimental conditions. Here, we demonstrate that miR-222 up-regulation, directly regulates Rad51c expression negatively, and impairs homologous recombination of double-strand break DNA repair during the initiation stage of cell transformation. This inhibition triggers morphological transformation in a two-stage Balb/c 3T3 cell assay, suggesting that this small RNA acts as an initiator of the carcinogenesis process.


Assuntos
Transformação Celular Neoplásica/genética , Proteínas de Ligação a DNA/genética , MicroRNAs/genética , Neoplasias/genética , Células 3T3 , Animais , Simulação por Computador , DNA/efeitos dos fármacos , DNA/genética , Reparo do DNA/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Recombinação Homóloga/efeitos dos fármacos , Recombinação Homóloga/genética , Humanos , Metais/metabolismo , Camundongos
4.
J Biochem Mol Toxicol ; 34(1): e22417, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31714652

RESUMO

The protective action of caffeic (CA) and syringic (SA) acids on the genotoxicity exercised by snake venoms was investigated in this study. Molecular interactions between phenolic acids and the enzyme succinate dehydrogenase were also explored. In the electrophoresis assay, SA did not inhibit the genotoxicity induced by the venom. However, CA partially inhibited DNA degradation. In the comet assay, SA and CA exerted an inhibitory effect on the venom-induced fragmentation. Succinate dehydrogenase presented, in computational analyzes, favorable energies to the molecular bond to both the malonic acid and the phenolic compounds evaluated. In the enzymatic activity assays, SA inhibited succinate dehydrogenase and interfered in the interaction of malonic acid. Meanwhile, CA potentiated the inhibition exerted by the malonic acid. The results suggest transient interactions between toxins present in venoms and phenolic acids, mainly by hydrogen interactions, which corroborate with the data from previous works.


Assuntos
DNA/efeitos dos fármacos , Hidroxibenzoatos/farmacologia , Mitocôndrias/efeitos dos fármacos , Succinato Desidrogenase/metabolismo , Adulto , Ensaio Cometa , Dano ao DNA , Feminino , Humanos , Masculino , Adulto Jovem
5.
Nat Genet ; 52(1): 48-55, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31844323

RESUMO

R-loops are nucleic acid structures formed by an RNA:DNA hybrid and unpaired single-stranded DNA that represent a source of genomic instability in mammalian cells1-4. Here we show that N6-methyladenosine (m6A) modification, contributing to different aspects of messenger RNA metabolism5,6, is detectable on the majority of RNA:DNA hybrids in human pluripotent stem cells. We demonstrate that m6A-containing R-loops accumulate during G2/M and are depleted at G0/G1 phases of the cell cycle, and that the m6A reader promoting mRNA degradation, YTHDF2 (ref. 7), interacts with R-loop-enriched loci in dividing cells. Consequently, YTHDF2 knockout leads to increased R-loop levels, cell growth retardation and accumulation of γH2AX, a marker for DNA double-strand breaks, in mammalian cells. Our results suggest that m6A regulates accumulation of R-loops, implying a role for this modification in safeguarding genomic stability.


Assuntos
Adenosina/análogos & derivados , DNA/química , Instabilidade Genômica , Células-Tronco Pluripotentes/metabolismo , Estabilidade de RNA/efeitos dos fármacos , Proteínas de Ligação a RNA/fisiologia , RNA/química , Adenosina/farmacologia , Animais , DNA/efeitos dos fármacos , DNA/genética , Dano ao DNA , Humanos , Camundongos , Camundongos Knockout , Mitose , Células-Tronco Pluripotentes/citologia , RNA/efeitos dos fármacos , RNA/genética , RNA Mensageiro/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
6.
Mutat Res ; 782: 108283, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31843137

RESUMO

Immuno-spin trapping detection of DNA radicals with the nitrone spin trap 5,5-dimethyl-1-pyrrloine N-oxide (DMPO) has made important contributions towards the understanding of DNA radicalization and genotoxicity at sites of inflammation. At sites of inflammation, one-electron oxidants and chloramines decay induce oxidation of genomic DNA, genotoxicity and cell transformation. Radicalization of DNA can result in either single- or double-strand breaks, or end-oxidation products at the sugar or bases. If not repaired, these modifications can lead to mutations and cell transformation. If trapped with DMPO, DNA-centered radical decay and subsequent formation of end-oxidation products are blocked. Herein we discuss recent literature regarding the use of immuno-spin trapping with DMPO to study DNA-centered radicals and their involvement in genotoxicity. This technique has shown the critical role of DNA radicalization in 8-oxo-dG formation and DNA strand breaks in isolated DNA, cells and in whole animals. Combination of technologies, including immuno-spin trapping and powerful chromatographic and sequencing techniques are needed to move forward the field towards the detection of specific genes that are susceptible to oxidative damage in cells located at sites of inflammation. This is important in order to provide novel information about genotoxicity mechanisms, as well as therapeutic possibilities of DMPO or its derivatives for preventing DNA-centered radical-mediated carcinogenesis.


Assuntos
Óxidos N-Cíclicos/efeitos adversos , Dano ao DNA/efeitos dos fármacos , DNA/efeitos dos fármacos , Radicais Livres/química , Mutagênicos/efeitos adversos , Óxidos de Nitrogênio/efeitos adversos , Óxidos de Nitrogênio/química , Animais , Inflamação/genética , Detecção de Spin/métodos
7.
PLoS One ; 14(12): e0216515, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31887110

RESUMO

The HIV genome is rich in A but not G or U and deficient in C. This nucleotide bias controls HIV phenotype by determining the highly unusual composition of all major HIV proteins. The bias is also responsible for the high frequency of narrow DNA minor groove sites in the double-stranded HIV genome as compared to cellular protein coding sequences and the bulk of the human genome. Since drugs that bind in the DNA minor groove disrupt nucleosomes on sequences that contain closely spaced oligo-A tracts which are prevalent in HIV DNA because of its bias, it was of interest to determine if these drugs exert this selective inhibitory effect on HIV chromatin. To test this possibility, nucleosomes were reconstituted onto five double-stranded DNA fragments from the HIV-1 pol gene in the presence and in the absence of several minor groove binding drugs (MGBDs). The results demonstrated that the MGBDs inhibited the assembly of nucleosomes onto all of the HIV-1 segments in a manner that was proportional to the A-bias, but had no detectable effect on the formation of nucleosomes on control cloned fragments or genomic DNA from chicken and human. Nucleosomes preassembled onto HIV DNA were also preferentially destabilized by the drugs as evidenced by enhanced nuclease accessibility in physiological ionic strength and by the preferential loss of the histone octamer in hyper-physiological salt solutions. The drugs also selectively disrupted HIV-containing nucleosomes in yeast as revealed by enhanced nuclease accessibility of the in vivo assembled HIV chromatin and reductions in superhelical densities of plasmid chromatin containing HIV sequences. A comparison of these results to the density of A-tracts in the HIV genome indicates that a large fraction of the nucleosomes that make up HIV chromatin should be preferred in vitro targets for the MGBDs. These results show that the MGBDs preferentially disrupt HIV-1 chromatin in vitro and in vivo and raise the possibility that non-toxic derivatives of certain MGBDs might serve as a novel class of anti-HIV agents.


Assuntos
Cromatina/efeitos dos fármacos , Cromatina/genética , HIV/genética , Sequência de Bases , Sítios de Ligação/genética , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina , Biologia Computacional/métodos , DNA/efeitos dos fármacos , DNA/genética , Genes pol/genética , HIV/metabolismo , Infecções por HIV/genética , Humanos
8.
Int J Mol Sci ; 21(1)2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31861648

RESUMO

Despite the effectiveness of cisplatin as an anticancer agent, its trans-isomer, transplatin, is clinically ineffective. Although both isomers target nuclear DNA, there is a large difference in the magnitude of their biological effects. Here, we compared their effects on gene expression in an in vitro luciferase assay and quantified their effects on the higher-order structure of DNA using fluorescence microscopy (FM) and atomic force microscopy (AFM). The inhibitory effect of cisplatin on gene expression was about 7 times that of transplatin. Analysis of the fluctuation autocorrelation function of the intrachain Brownian motion of individual DNA molecules showed that cisplatin increases the spring and damping constants of DNA by one order of magnitude and these visco-elastic characteristics tend to increase gradually over several hours. Transplatin had a weaker effect, which tended to decrease with time. These results agree with a stronger inhibitory effect of cisplatin on gene expression. We discussed the characteristic effects of the two compounds on the higher-order DNA structure and gene expression in terms of the differences in their binding to DNA.


Assuntos
Cisplatino/farmacologia , DNA/química , Bacteriófago T4/química , Bacteriófago T4/genética , DNA/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Microscopia de Força Atômica , Microscopia de Fluorescência , Conformação de Ácido Nucleico , Plasmídeos/química , Plasmídeos/genética
9.
Inorg Chem ; 58(23): 16154-16170, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31721562

RESUMO

In this study, two new bis-cyclometalated Pt(II) complexes, [Pt(C^N)(S^N)] [S^N = deprotonated 6-mercaptopurine (6-MP) and C^N = deprotonated 2-phenylpyridine (ppy), 2a; C^N = deprotonated benzo[h]quinoline (bhq), 2b], are synthesized by the reaction of [PtR(SMe2)(C^N)] (R = Me or p-MeC6H4) with 1 equiv of 6-mercaptopurine (6-HMP) at room temperature. The complexes are fully characterized using 1H and 13C NMR spectroscopies, electrospray ionization mass spectrometry, and elemental analysis. Biomolecular interaction of complex 2a with human serum albumin (HSA) is studied by fluorescence, UV-vis, and circular dichroism (CD) spectroscopies. The binding constants (Kb) and number of binding sites (n) are evaluated using the Stern-Volmer equation. The intrinsic fluorescence of protein is quenched by a static quenching mechanism, with a binding constant of Kb ∼ 105 reflecting a high affinity of complex 2a for HSA. The thermodynamic parameters (ΔH°, ΔG°, and ΔS°) indicate that the interaction is a spontaneous process and hydrophobic forces play a main role in the reaction. The displacement experiments demonstrate that the reactive binding sites of HSA to complex 2a are mainly located within its hydrophobic cavity in subdomain IIA (site I). Synchronous fluorescence spectra reveal that complex 2a affected the microenvironment of tryptophan-214 residues in subdomain IIA of HSA. In the case of interaction of complex 2b and HSA, because of overlapping of the emission spectra of complex 2b with HSA, chemometric approaches are applied. The results indicate significant interaction between the tryptophan residue of HSA and complex 2b. Moreover, the binding of Pt(II) complexes 2a and 2b causes a reduction of the α-helix content of HSA, as obtained by far-UV CD spectroscopy. The average binding distance (r) between Pt(II) complexes and HSA is obtained by Förster's resonance energy-transfer theory. Also, a molecular docking simulation reveals that π-π-stacking and hydrophobic interactions between these complexes and HSA are significant. Furthermore, the interactions of platinum complexes, 2, with calf-thymus DNA (CT-DNA) are investigated. The UV-vis results and ethidium bromide competitive studies support an intercalative interaction of both Pt(II) complexes with DNA. The new complexes 2 are also screened for anticancer activities. The results show that complexes 2 exhibit significant anticancer activity against the K562 (chronic myelogenous leukemia) cell line.


Assuntos
Antineoplásicos/farmacologia , DNA/efeitos dos fármacos , Mercaptopurina/farmacologia , Compostos Organoplatínicos/farmacologia , Albumina Sérica Humana/efeitos dos fármacos , Antineoplásicos/síntese química , Antineoplásicos/química , Sítios de Ligação/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , DNA/química , Teoria da Densidade Funcional , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Células K562 , Mercaptopurina/química , Simulação de Acoplamento Molecular , Estrutura Molecular , Compostos Organoplatínicos/síntese química , Compostos Organoplatínicos/química , Albumina Sérica Humana/química , Relação Estrutura-Atividade , Termodinâmica
10.
Chem Commun (Camb) ; 55(87): 13082-13084, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31608901

RESUMO

Herein, a photoelectrochemical biosensor was successfully constructed on the basis of a sensitization strategy of doxorubicin sensitized graphitic carbon nitride for the ultrasensitive detection of microRNA-141 with the assistance of a target-activated enzyme-free DNA walker.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Técnicas Biossensoriais , DNA/efeitos dos fármacos , Doxorrubicina/farmacologia , Técnicas Eletroquímicas , Grafite/química , MicroRNAs/análise , Compostos de Nitrogênio/química , Antibióticos Antineoplásicos/química , Doxorrubicina/química , Processos Fotoquímicos
11.
Nat Commun ; 10(1): 4846, 2019 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-31649282

RESUMO

DNA topoisomerases are required to resolve DNA topological stress. Despite this essential role, abortive topoisomerase activity generates aberrant protein-linked DNA breaks, jeopardising genome stability. Here, to understand the genomic distribution and mechanisms underpinning topoisomerase-induced DNA breaks, we map Top2 DNA cleavage with strand-specific nucleotide resolution across the S. cerevisiae and human genomes-and use the meiotic Spo11 protein to validate the broad applicability of this method to explore the role of diverse topoisomerase family members. Our data characterises Mre11-dependent repair in yeast and defines two strikingly different fractions of Top2 activity in humans: tightly localised CTCF-proximal, and broadly distributed transcription-proximal, the latter correlated with gene length and expression. Moreover, single nucleotide accuracy reveals the influence primary DNA sequence has upon Top2 cleavage-distinguishing sites likely to form canonical DNA double-strand breaks (DSBs) from those predisposed to form strand-biased DNA single-strand breaks (SSBs) induced by etoposide (VP16) in vivo.


Assuntos
Reparo do DNA , DNA Topoisomerases Tipo II/metabolismo , DNA/metabolismo , Endodesoxirribonucleases/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Antineoplásicos Fitogênicos/farmacologia , Sequência de Bases , Fator de Ligação a CCCTC/genética , DNA/efeitos dos fármacos , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Quebras de DNA de Cadeia Simples/efeitos dos fármacos , Etoposídeo/farmacologia , Humanos , Mapeamento de Nucleotídeos
12.
Comput Biol Chem ; 83: 107114, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31493741

RESUMO

Pittosporum senacia (PS) Putt. (Pittosporaceae), indigenous to the Mascarene Islands, is a common ingredient in traditional medicines. However, there is currently a dearth of studies to validate some of these traditional claims. Given the broad traditional uses of PS against several diseases, we aimed to provide a comprehensive insight into the biological and chemical profile of P. senacia. The antioxidant, enzyme inhibitory activity, anticancer, and phytochemical composition of the methanolic extract of P. senacia leaf extracts were studied. The possible interaction and binding mode of the most abundant phytochemicals were studied via in silico docking experiments on tyrosinase and α-glucosidase. The mechanism behind the cytotoxic property of P. senacia extract for MDA-MB-231 was also examined using different methods including 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability test checking apoptosis-associated genes, and wound healing assays. Twenty-six compounds were identified, of which caffeoylquinic acid derivatives, ferulic acid derivative, cinnamoylquinic acid derivative and two other polyphenols (oleuropeine and isoramnetin glucoside) being abundant, have been tested using in silico studies, against α-glucosidase and tyrosinase. The extract (IC50 = 118.8 µg/ml) exhibited time and dose dependent anti-proliferative effect on human breast cancer cell line, MDA-MB-231. According to the expression profile of apoptosis inhibitors and apoptosis promoters genes, expression of Bax and Bak genes were significantly increased compared to Bcl-2 and Birc5 genes. Based on wound healing analysis, cell migration was inhibited after the application of the plant extract. The present findings suggested that PS might be a good candidate as sources of bioactive compounds for designing functional applications.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , DNA/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Simulação de Acoplamento Molecular , Extratos Vegetais/farmacologia , Rosales/química , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Plasmídeos/efeitos dos fármacos , Espectrometria de Massas por Ionização por Electrospray , Células Tumorais Cultivadas , alfa-Glucosidases/metabolismo
13.
Environ Mol Mutagen ; 60(9): 792-806, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31374128

RESUMO

Aristolochic acids (AAs) are human nephrotoxins and carcinogens found in concoctions of Aristolochia plants used in traditional medicinal practices worldwide. Genotoxicity of AAs is associated with the formation of active species catalyzed by metabolic enzymes, the full repertoire of which is unknown. Recently, we provided evidence that sulfonation is important for bioactivation of AAs. Here, we employ Salmonella typhimurium umu tester strains expressing human N-acetyltransferases (NATs) and sulfotransferases (SULTs), to study the role of conjugation reactions in the genotoxicities of N-hydroxyaristolactams (AL-I-NOH and AL-II-NOH), metabolites of AA-I and AA-II. Both N-hydroxyaristolactams show stronger genotoxic effects in umu strains expressing human NAT1 and NAT2, than in the parent strain. Additionally, AL-I-NOH displays increased genotoxicity in strains expressing human SULT1A1 and SULT1A2, whereas AL-II-NOH shows enhanced genotoxicity in SULT1A1/2 and SULT1A3 strains. 2,6-Dichloro-4-nitrophenol, SULTs inhibitor, reduced umuC gene expression induced by N-hydroxyaristolactams in SULT1A2 strain. N-hydroxyaristolactams are also mutagenic in parent strains, suggesting that an additional mechanism(s) may contribute to their genotoxicities. Accordingly, using putative SULT substrates and inhibitors, we found that cytosols obtained from human kidney HK-2 cells activate N-hydroxyaristolactams in aristolactam-DNA adducts with the limited involvement of SULTs. Removal of low-molecular-weight reactants in the 3.5-10 kDa range inhibits the formation of aristolactam-DNA by 500-fold, which could not be prevented by the addition of cofactors for SULTs and NATs. In conclusion, our results demonstrate that the genotoxicities of N-hydroxyaristolactams depend on the cell type and involve not only sulfonation but also N,O-acetyltransfer and an additional yet unknown mechanism(s). Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.


Assuntos
Ácidos Aristolóquicos/metabolismo , Ácidos Aristolóquicos/toxicidade , Acetiltransferases/metabolismo , Arilamina N-Acetiltransferase/metabolismo , Arilsulfotransferase/metabolismo , Carcinógenos/toxicidade , Linhagem Celular , DNA/efeitos dos fármacos , Adutos de DNA/genética , Humanos , Mutagênicos/toxicidade , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/metabolismo , Sulfotransferases/metabolismo
14.
Environ Mol Mutagen ; 60(9): 778-791, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31294873

RESUMO

Nicotine's genotoxic potential has been extensively studied in vitro. While the results of mammalian cell-based studies have inferred that it can potentially damage chromosomes, in general and with few exceptions, adverse DNA effects have been observed primarily at supraphysiological concentrations in nonregulatory assays that provide little information on its mode-of-action (MoA). In this study, a modern-day regulatory genotoxicity assessment was conducted using a flow cytometry-based in vitro micronucleus (MN) assay, Good Laboratory Practice study conditions, Chinese hamster ovary cells of known provenance, and acceptance/evaluation criteria from the current OECD Test Guideline 487. Nicotine concentrations up to 3.95 mM had no effect on background levels of DNA damage; however, concentrations above the point-of-departure range of 3.94-4.54 mM induced increases in MN and hypodiploid nuclei, indicating a possible aneugenicity hazard. Follow-up experiments designed to elucidate nicotine's MoA revealed cellular vacuolization, accompanying distortions in microtubules, inhibition of tubulin polymerization, centromere-positive DNA, and multinucleate cells at MN-inducing concentrations. Vacuoles likely originated from acidic cellular compartments (e.g., lysosomes). Remarkably, genotoxicity was suppressed by chemicals that raised the luminal pH of these organelles. Other endpoints (e.g., changes in phosphorylated histones) measured in the study cast doubt on the biological relevance of this apparent genotoxicity. In addition, three major nicotine metabolites, including cotinine, had no MN effects but nornicotine induced a nicotine-like profile. It is possible that nicotine's lysosomotropic properties drive the genotoxicity observed in vitro; however, the potency and mechanistic insights revealed here indicate that it is likely of minimal physiological relevance for nicotine consumers. Environ. Mol. Mutagen. 2019. © 2019 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.


Assuntos
Núcleo Celular/efeitos dos fármacos , Nicotina/toxicidade , Aneugênicos/toxicidade , Animais , Células CHO , Linhagem Celular , Núcleo Celular/metabolismo , Cricetulus , DNA/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Testes para Micronúcleos/métodos , Microtúbulos/efeitos dos fármacos , Testes de Mutagenicidade/métodos , Mutagênicos/toxicidade , Nicotina/análogos & derivados , Fosforilação/efeitos dos fármacos , Tubulina (Proteína)/metabolismo
15.
Cell Mol Biol Lett ; 24: 42, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31236120

RESUMO

Human bronchial epithelium (HBE)-Dp71 anti-sense(AS)cells with stably transfected Dp71 siRNA plasmids were prepared for further exploration of Dp71 biological traits in cells other than PC12. HBE-Dp71AS cells displayed increased DNA damage induced by H2O2. Apoptosis of HBE-Dp71AS cells induced by H2O2 was increased via enhancing caspase 3, caspase 8 and caspase 9. HBE-Dp71AS cells also displayed decreased proliferation and clonogenic formation. RAD51 was proved to be a new binding partner of Dp71 by co-immunoprecipitation (Ip) and immunofluorescence. Reduced RAD51 mRNA and protein levels were observed in HBE-Dp71AS cells. Decreased lamin B1, focal adhesion kinase (FAK), phosphorylated focal adhesion kinase (p-FAK) and phosphorylated protein kinase B (p-AKT) were detected in the HBE-Dp71AS cells, which functioned together with RAD51 as the molecular explanations for the character alterations of HBE-Dp71AS cells.


Assuntos
Apoptose , Dano ao DNA , Distrofina/metabolismo , Peróxido de Hidrogênio/toxicidade , Estresse Oxidativo , Rad51 Recombinase/genética , Linhagem Celular , DNA/efeitos dos fármacos , DNA/metabolismo , Reparo do DNA , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Quinase 1 de Adesão Focal/genética , Quinase 1 de Adesão Focal/metabolismo , Regulação da Expressão Gênica , Humanos , Peróxido de Hidrogênio/farmacologia , Lamina Tipo B/genética , Fosforilação , Processamento de Proteína Pós-Traducional , Rad51 Recombinase/metabolismo
16.
Urologiia ; (1): 78-83, 2019 Apr.
Artigo em Russo | MEDLINE | ID: mdl-31184022

RESUMO

AIM: docosahexaenoic acid is one of the most common fatty acids in the cell membranes of sperm. This substance is a structural component of cell membranes, and is responsible for such properties as plasticity and fluidity which are necessary for the implementation of the process of capacitation and acrosome reaction. In addition, docosahexaenoic acid has antioxidant properties. Aim of our study was to assess the effect of dietary supplement docosahexaenoic acid (Brudi PLUS) on such markers of male fertility as the sperm DNA integrity, standard indicators of semen analysis and cryotolerance in infertile men. MATERIALS AND METHODS: a randomized, multicenter, double-blind, placebo-controlled study was conducted. A total of 109 infertile men were recruited to participate in the study. All patients underwent different analyzes, including semen analysis, sperm DNA fragmentation, MAR-test, test of cryotolerance and electron microscopy analysis of spermatozoa. In active treatment group patients were prescribed to drug containing 350 mg of docosahexaenoic acid 3 times a day for 90 days. In the control group, patients were administered to a placebo with a similar scheme. All analyzes were repeatedly performed after 3-months of therapy. RESULTS: An increase in the progressive mobility and sperm viability was determined after the test of cryotolerance in the active treatment group. According to electron microscopy analysis of spermatozoa, positive changes were observed in the number of heads of the normal form with the normal structure of chromatin and acrosome, as well as a decrease in the number of spermatozoa with insufficiently condensed chromatin. CONCLUSIONS: the therapy with drug Brudi PLUS in patients with male infertility allows to increase in cryotolerance of sperms as well as decrease in number of sperm ultrastructure defects.


Assuntos
Ácidos Docosa-Hexaenoicos , Infertilidade Masculina , Adulto , DNA/efeitos dos fármacos , Ácidos Docosa-Hexaenoicos/uso terapêutico , Método Duplo-Cego , Humanos , Infertilidade Masculina/tratamento farmacológico , Masculino , Análise do Sêmen , Espermatozoides/efeitos dos fármacos
17.
Nucleic Acids Res ; 47(13): 6578-6589, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31188442

RESUMO

Higher-ordered structure motifs of nucleic acids, such as the G-quadruplex (G-4), mismatched and bulge structures, are significant research targets because these structures are involved in genetic control and diseases. Selective alkylation of these higher-order structures is challenging due to the chemical instability of the alkylating agent and side-reactions with the single- or double-strand DNA and RNA. We now report the reactive OFF-ON type alkylating agents, vinyl-quinazolinone (VQ) precursors with a sulfoxide, thiophenyl or thiomethyl group for the OFF-ON control of the vinyl reactivity. The stable VQ precursors conjugated with aminoacridine, which bind to the G-4 DNA, selectively reacted with a T base on the G-4 DNA in contrast to the single- and double-strand DNA. Additionally, the VQ precursor reacted with the T or U base in the AP-site, G-4 RNA and T-T mismatch structures. These VQ precursors would be a new candidate for the T or U specific alkylation in the higher-ordered structures of nucleic acids.


Assuntos
Alquilantes/farmacologia , DNA/efeitos dos fármacos , Conformação de Ácido Nucleico/efeitos dos fármacos , Alquilantes/síntese química , Alquilantes/química , Alquilação , Pareamento de Bases , DNA/química , DNA de Cadeia Simples/química , DNA de Cadeia Simples/efeitos dos fármacos , Quadruplex G/efeitos dos fármacos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Purinas/química , Purinas/farmacologia , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Relação Estrutura-Atividade , Triazinas/química , Triazinas/farmacologia , Compostos de Vinila/química , Compostos de Vinila/farmacologia
18.
Andrologia ; 51(8): e13313, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31179568

RESUMO

Reproductive dysfunction is one of the diabetes complications. Resveratrol, a polyphenol compound, shows antidiabetic and antioxidant effects. The aim of the present study was to investigate the protective effects of resveratrol on sperm parameters and chromatin quality in experimentally induced type 2 diabetes by streptozotocin and nicotinamide. Forty male adult Wistar rats were grouped into normal control, diabetic control and resveratrol-treated diabetic groups (1, 5 and 10 mg/kg orally treated for 30 days). Type 2 diabetes was induced using a single dose of streptozotocin and nicotinamide by intraperitoneal injection. Then, the different parameters and chromatin condensation of the epididymal extracted spermatozoon were studied using aniline blue (AB), acridine orange (AO) and toluidine blue (TB) staining. The sperm parameters including count, motility and viability had significant reduction in diabetic rats (p < 0.05). Resveratrol increased count, motility and viable spermatozoa relative to the diabetic group (p < 0.05). The mean percentage of AB, AO and TB staining positive spermatozoa was increased in diabetic groups compared to control (p < 0.001) and decreased after treatment with 1 and 5 mg/kg resveratrol (p < 0.001). The results of AO and TB staining showed that resveratrol did not have any beneficial effect on chromatin condensation and denatured DNA at the dose of 10 mg/kg.


Assuntos
Antioxidantes/administração & dosagem , Diabetes Mellitus Tipo 2/complicações , Suplementos Nutricionais , Infertilidade Masculina/prevenção & controle , Resveratrol/administração & dosagem , Animais , Cromatina/efeitos dos fármacos , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , DNA/efeitos dos fármacos , DNA/metabolismo , Fragmentação do DNA/efeitos dos fármacos , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Tipo 2/induzido quimicamente , Relação Dose-Resposta a Droga , Humanos , Infertilidade Masculina/etiologia , Infertilidade Masculina/patologia , Masculino , Niacinamida/toxicidade , Ratos , Ratos Wistar , Contagem de Espermatozoides , Motilidade Espermática/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Espermatozoides/patologia , Estreptozocina/toxicidade , Resultado do Tratamento
19.
Eur J Med Chem ; 179: 166-181, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31254919

RESUMO

This work did a new exploration towards aminothiazolquinolone oximes as potentially multi-targeting antimicrobial agents. A class of novel hybrids of quinolone, aminothiazole, piperazine and oxime fragments were designed for the first time, conveniently synthesized as well as characterized by 1H NMR, 13C NMR and HRMS spectra. Biological activity showed that some of the synthesized compounds exhibited good antimicrobial activities in comparison with the reference drugs. Especially, O-methyl oxime derivative 10b displayed excellent inhibitory efficacy against MRSA and S. aureus 25923 with MIC values of 0.009 and 0.017 mM, respectively. Further studies indicated that the highly active compound 10b showed low toxicity toward BEAS-2B and A549 cell lines and no obvious propensity to trigger the development of bacterial resistance. Quantum chemical studies have also been conducted and rationally explained the structural features essential for activity. The preliminarily mechanism exploration revealed that compound 10b could not only exert efficient membrane permeability by interfering with the integrity of cells, bind with topoisomerase IV-DNA complex through hydrogen bonds and π-π stacking, but also form a steady biosupramolecular complex by intercalating into DNA to exert the efficient antibacterial activity. The supramolecular interaction between compound 10b and human serum albumin (HSA) was a static quenching, and the binding process was spontaneous, where hydrogen bonds and van der Waals force played vital roles in the supramolecular transportation of the active compound 10b by HSA.


Assuntos
Antibacterianos/farmacologia , Desenho de Fármacos , Oximas/farmacologia , Quinolonas/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , DNA/efeitos dos fármacos , DNA Topoisomerase IV/antagonistas & inibidores , DNA Topoisomerase IV/metabolismo , Relação Dose-Resposta a Droga , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Oximas/síntese química , Oximas/química , Teoria Quântica , Quinolonas/síntese química , Quinolonas/química , Albumina Sérica Humana/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Relação Estrutura-Atividade
20.
PLoS One ; 14(6): e0218924, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31237931

RESUMO

Propidium monoazide (PMA) is a highly selective dye that penetrates only membrane-compromised, dead microbial cells and inhibits both DNA extraction and amplification. PMA has been widely used for discrimination between living and dead microbial cells; however, the application of PMA in phytoplankton studies has been limited. In this study, we attempted to evaluate its applicability for the discrimination of viable phytoplankton. We tested PMA on seven phytoplankton species, Microcystis aeruginosa, Anabaena sp., Aphanizomenon sp., Synechocystis sp., Cryptomonas ovata, Scenedesmus obliquus, and Nitzschia apiculata as representatives of the major phytoplankton taxa Cyanobacteria (first four species), Chlorophyta, Cryptophyta, and Bacillariophyta, respectively. Our results showed that application of PMA to phytoplankton living in freshwater has the potential to distinguish viable from dead cells as in microbial studies. Particularly, PMA differentiated viable from dead cells in cyanobacterial species rather than in other phytoplankton taxa under our experimental conditions. However, our results also showed that it may be necessary to adjust various conditions affecting PMA treatment efficiency to expand its applicability to other phytoplankton. Although all factors contributing to the effects of PMA could not be evaluated, our study showed the applicability of PMA-based molecular approaches, which can be convenient quantitative methods for distinguishing living from dead phytoplankton in freshwater ecosystems. Setting optimal treatment conditions for other phytoplankton species may increase the efficacy of PMA-based molecular approaches.


Assuntos
Azidas/farmacologia , Fitoplâncton/efeitos dos fármacos , Propídio/análogos & derivados , DNA/efeitos dos fármacos , Ecossistema , Água Doce , Propídio/farmacologia
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