RESUMEN
Double strand break (DSB) repair through Homologous Recombination (HR) is essential in maintaining genomic stability of the cell. Mutations in the HR pathway confer an increased risk for breast, ovarian, pancreatic and prostate cancer. PARP inhibitors (PARPi) are compounds that specifically target tumours deficient in HR. Novel PARPi are constantly being developed, but research is still heavily focussed on in vitro data, with mouse xenografts only being used in late stages of development. There is a need for assays that can: 1) provide in vivo data, 2) early in the development process of novel PARPi, 3) provide fast results and 4) at an affordable cost. Here we propose a combination of in vivo zebrafish assays to accurately quantify PARP inhibitor efficacy. We showed that PARPi display functional effects in zebrafish, generally correlating with their PARP trapping capacities. Furthermore, we displayed how olaparib mediated radiosensitization is conserved in our zebrafish model. These assays could aid the development of novel PARPi by providing early in vivo data. In addition, using zebrafish allows for high-throughput testing of combination therapies in search of novel treatment strategies.
Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , Modelos Animales , Mutación , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Reparación del ADN por Recombinación , Pez Cebra/genética , Animales , Animales Modificados Genéticamente , Antineoplásicos/farmacología , Proteína BRCA2/genética , ADN/metabolismo , ADN/efectos de la radiación , Ftalazinas/farmacología , Piperazinas/farmacología , Pez Cebra/metabolismo , Proteínas de Pez Cebra/genéticaRESUMEN
Male infertility is a worldwide critical condition that affects about the 7.5% of males in Europe leading to an increment of the couples referring to reproductive medicine units to achieve pregnancy. Moreover, in the recent years, an increased number of patients have required to freeze their gametes in order to preserve their fertility. Photobiomodulation (PBM) therapy is a potential treatment that has been used for different clinical application basically aimed at biostimulating cells and tissues. Here, we report a deep overview of the published studies, focusing on PBM mechanism of action, with the aim of expanding the knowledge in the field of laser light for a rational utilization of irradiation in the clinical practice. In the field of reproductive science, PBM was employed to increment spermatozoa's metabolism, motility, and viability, due to its beneficial action on mitochondria, leading to an activation of the mitochondrial respiratory chain and to the ATP production. This treatment can be particularly useful to avoid the use of chemicals in the spermatozoa culture medium as well as to promote the spermatozoa survival and movement especially after thawing or in largely immotile sperm samples.
Asunto(s)
Infertilidad Masculina/radioterapia , Terapia por Luz de Baja Intensidad , ADN/efectos de la radiación , Humanos , Infertilidad Masculina/diagnóstico , Infertilidad Masculina/etiología , Masculino , Motilidad Espermática/efectos de la radiación , Espermatozoides/efectos de la radiaciónRESUMEN
There is increasing evidence that environmental exposures early in fetal development influence phenotype and give rise to disease risk in the next generations. We previously found that lifelong exposure to uranium, an environmental contaminant, induced subtle testicular and hormonal defects; however, its impact on the reproductive system of multiple subsequent generations was unexplored. Herein, rats were exposed to a supra-environmental and non-nephrotoxic concentration of natural uranium (U, 40 mg·L-1 of drinking water) from postnatal life to adulthood (F0), during fetal life (F1), and only as the germ cells from the F1 generation (F2). General parameters (reproductive indices, epididymal weight) and sperm morphology were assessed in the three generations. In order to identify the epigenetic effects of U, we analyzed also the global DNA methylation profile and described for the first time the mRNA expression levels of markers involved in the (de)methylation system in rat epididymal spermatozoa. Our results showed that the F1 generation had a reduced pregnancy rate. Despite the sperm number being unmodified, sperm morphology was affected in the F0, F1 and F2 generations. Morphometric analysis for ten parameters was detailed for each generation. No common parameter was detected between the three generations, but the head and the middle-piece were always modified in the abnormal sperms. In the F1 U-exposed generation, the total number of abnormal sperm was significantly higher than in the F0 and F2 generations, suggesting that fetal exposure to uranium was more deleterious. This effect could be associated with the pregnancy rate to produce the F2 generation. Interestingly, global DNA methylation analysis showed also hypomethylation in the sperm DNA of the last F2 generation. In conclusion, our study demonstrates that uranium can induce morphological sperm defects and changes in the DNA methylation level after multigenerational exposure. The epigenetic transgenerational inheritance of U-induced reproductive defects should be assessed in further experiments.
Asunto(s)
Metilación de ADN/efectos de la radiación , Espermatozoides/efectos de la radiación , Espermatozoides/ultraestructura , Uranio/toxicidad , Animales , ADN/efectos de la radiación , Contaminación Ambiental , Epidídimo/patología , Epidídimo/efectos de la radiación , Epigénesis Genética/efectos de la radiación , Femenino , Feto/efectos de la radiación , Células Germinativas/efectos de la radiación , Masculino , Embarazo , Ratas , Ratas Sprague-Dawley , Reproducción/efectos de la radiaciónRESUMEN
Rhodopsin, composed of opsin and isomeric retinal, acts as the primary photoreceptor by converting light into electric signals. Inspired by rhodopsin, we have fabricated a light-regulated ionic gate on the basis of the design of a graphene oxide (GO)-biomimetic DNA-nanochannel architecture. In this design, photoswitchable azobenzene (Azo)-DNA is introduced to the surface of porous anodic alumina (PAA) membrane. With modulation of the interaction between the GO blocker and Azo-DNA via flexibly regulating trans and cis states of Azo under the irradiation of visible and ultraviolet light, alternatively, the ionic gate is switched between ON and OFF states. This newly constructed ionic gate can possess high efficiency for the control of ion transport because of the high blocking property of GO and the rather tiny path within the barrier layer which are both first employed to fabricate ionic gate. We anticipate that this rhodopsin-like ionic gate may provide a new model and method for the investigation of ion channel, ion function, and ion quantity. In addition, because of the advantages of simple fabrication, good biocompatibility, and universality, this bioinspired system may have potential applications as optical sensors, in photoelectric transformation, and in controllable drug delivery.
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Materiales Biomiméticos/química , ADN/química , Grafito/química , Transporte Iónico/efectos de los fármacos , Óxido de Aluminio/química , Compuestos Azo/química , Compuestos Azo/efectos de la radiación , Materiales Biomiméticos/efectos de la radiación , ADN/efectos de la radiación , Técnicas Electroquímicas , Grafito/efectos de la radiación , Transporte Iónico/efectos de la radiación , Membranas Artificiales , Rodopsina/química , Estereoisomerismo , Rayos UltravioletaRESUMEN
The present study evaluated the potential of 2100 MHz radiofrequency radiations to act as cytotoxic and genotoxic agent. Fresh onion (Allium cepa L.) roots were exposed to electromagnetic field radiations (EMF-r) for different durations (1 h and 4 h) and evaluated for mitotic index (MI), phase index, chromosomal aberrations, and DNA damage. DNA damage was investigated with the help of the comet assay by assessing various parameters like % head DNA (HDNA), % tail DNA (TDNA), tail moment (TM), and olive tail moment (OTM). Effects of EMF-r exposure were also compared with that of methyl methanesulfonate (MMS; 90 µM), which acted as a positive control. The post-exposure effects of EMF-r after providing the test plants with an acclimatization period of 24 h were also evaluated. Compared to the control, a significant increase in the MI and aberration percentage was recorded upon 4 h of exposure. However, no specific trend of phase index in response to exposure was detected. EMF-r exposure incited DNA damage with a significant decrease in HDNA accompanied by an increase in TDNA upon exposure of 4 h. However, TM and OTM did not change significantly upon exposure as compared to that of control. Analysis of the post-exposure effects of EMF-r did not show any significant change/recovery. Our data, thus, suggest the potential cytotoxic and genotoxic nature of 2100 MHz EMF-r. Our study bears great significance in view of the swiftly emergent EMF-r in the surrounding environment and their potential for inciting aberrations at the chromosomal level, thus posing a genetic hazard.
Asunto(s)
Teléfono Celular/tendencias , ADN/efectos de la radiación , Radiación Electromagnética , Meristema/efectos de los fármacos , Índice Mitótico/métodos , Cebollas/efectos de los fármacosRESUMEN
Based on the fluorescent reversible regulation, a novel sensor platform was designed for the detection of DNA intercalators utilizing the intercalation binding of DNA intercalators to DNA as an inherent exhibition and the fluorescence change of quantum dots (QDs) as an external manifestation. To prove its feasibility, acridine orange (AO) was chosen as an example of DNA intercalator. When different concentrations of herring sperm DNA (hsDNA) were added to cysteamine (CA)-capped ZnSe QDs solution, the hsDNA bound with the QDs through electrostatic interaction due to the photoinduced electron transfer from hsDNA to QDs and formed QDs-hsDNA complexes with 1:1 ratio, leading to the fluorescence quenching of the QDs; and upon addition of different concentrations of AO to the QDs-hsDNA complex system, the AO first caused the release of the hsDNA from the complexes and concomitantly bound with them through intercalation binding and formed AO-hsDNA complexes with 1:3 ratio on account of the fact that the intercalation binding constant between AO and hsDNA (1.932â¯×â¯105 L/mol) was greater than the electrostatic interaction constant between QDs and hsDNA (7.874â¯×â¯104 L/mol), resulting in the fluorescence recovery of the QDs. Therefore, the detection of AO could be achieved through the relationship between the fluorescence recovery yield of the QDs and the concentration of AO added. The results illustrated that the fluorescence recovery yield of the QDs-hsDNA system was linearly dependent to the concentration of AO in the range of 5.0-75.0â¯×â¯10-5 mol/L with a detection limit (3σ/K) of 1.5â¯×â¯10-5 mol/L. This dual-directional fluorescent regulation provided a novel method for the detection of DNA intercalators such as polycyclic aromatic hydrocarbons and drugs interfering with DNA-synthesis and possessed some potential applications in the investigation of the interactions between DNA intercalators and DNA.
Asunto(s)
Naranja de Acridina/análisis , ADN/química , Electrones , Sustancias Intercalantes/análisis , Puntos Cuánticos/química , Espectrometría de Fluorescencia/métodos , Animales , Cisteamina/química , ADN/efectos de la radiación , Peces/genética , Fluorescencia , Luz , Límite de Detección , Masculino , Selenio/química , Espermatozoides/química , Zinc/químicaRESUMEN
One approach to protect the human skin against harmful effects of solar ultraviolet (UV) radiation was to use natural products as photoprotectors. In this work, the extract from specie Phyllanthus orbicularis K was evaluated as a protective agent against the photodamage by UVB, UVA artificial lamps, and environmental sunlight exposure. The plasmid DNA solutions were exposed to radiations using the DNA dosimeter system in the presence of plant extract. The DNA repair enzymes, Escherichia coli Formamidopyrimidine-DNA glycosylase (Fpg) and T4 bacteriophage endonuclease V (T4-endo V), were employed to discriminate oxidized DNA damage and cyclobutane pyrimidine dimers (CPD), respectively. The supercoiled and relaxed forms of DNA were separated through electrophoretic migration in agarose gels. These DNA forms were quantified to determine strand break, representing the types of lesion levels. The results showed that, in the presence of P. orbicularis extract, the CPD and oxidative damage were reduced in irradiated DNA samples. The photoprotective effect of extract was more evident for UVB and sunlight radiation than for UVA. This work documented the UV absorbing properties of P. orbicularis aqueous extract and opened up new vistas in its characterization as protective agent against DNA damage induced by environmental sunlight radiation.
Asunto(s)
Antimutagênicos/farmacología , Phyllanthus/química , Extractos Vegetales/farmacología , Protectores contra Radiación/farmacología , Luz Solar/efectos adversos , Rayos Ultravioleta/efectos adversos , ADN/efectos de la radiación , Daño del ADN , ADN-Formamidopirimidina Glicosilasa/metabolismo , Desoxirribonucleasa (Dímero de Pirimidina)/metabolismo , Electroforesis en Gel de Agar , Escherichia coli/enzimología , Proteínas de Escherichia coli/metabolismo , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/efectos de la radiación , Plásmidos , Dímeros de Pirimidina/metabolismo , Proteínas Virales/metabolismoRESUMEN
The DNA Damage Response (DDR) uses a plethora of proteins to detect, signal, and repair DNA lesions. Delineating this response is critical to understand genome maintenance mechanisms. Since recruitment and exchange of proteins at lesions are highly dynamic, their study requires the ability to generate DNA damage in a rapid and spatially-delimited manner. Here, we describe procedures to locally induce DNA damage in human cells using a commonly available laser-scanning confocal microscope equipped with a 405 nm laser line. Accumulation of genome maintenance factors at laser stripes can be assessed by immunofluorescence (IF) or in real-time using proteins tagged with fluorescent reporters. Using phosphorylated histone H2A.X (γ-H2A.X) and Replication Protein A (RPA) as markers, the method provides sufficient resolution to discriminate locally-recruited factors from those that spread on adjacent chromatin. We further provide ImageJ-based scripts to efficiently monitor the kinetics of protein relocalization at DNA damage sites. These refinements greatly simplify the study of the DDR dynamics.
Asunto(s)
Daño del ADN/efectos de la radiación , ADN/efectos de la radiación , Técnica del Anticuerpo Fluorescente/métodos , Terapia por Luz de Baja Intensidad/métodos , Microscopía Confocal/métodos , HumanosRESUMEN
During cancer radiation therapy high-energy radiation is used to reduce tumour tissue. The irradiation produces a shower of secondary low-energy (<20â eV) electrons, which are able to damage DNA very efficiently by dissociative electron attachment. Recently, it was suggested that low-energy electron-induced DNA strand breaks strongly depend on the specific DNA sequence with a high sensitivity of G-rich sequences. Here, we use DNA origami platforms to expose G-rich telomere sequences to low-energy (8.8â eV) electrons to determine absolute cross sections for strand breakage and to study the influence of sequence modifications and topology of telomeric DNA on the strand breakage. We find that the telomeric DNA 5'-(TTAâ GGG)2 is more sensitive to low-energy electrons than an intermixed sequence 5'-(TGTâ GTGâ A)2 confirming the unique electronic properties resulting from G-stacking. With increasing length of the oligonucleotide (i.e., going from 5'-(GGGâ ATT)2 to 5'-(GGGâ ATT)4 ), both the variety of topology and the electron-induced strand break cross sections increase. Addition of K+ ions decreases the strand break cross section for all sequences that are able to fold G-quadruplexes or G-intermediates, whereas the strand break cross section for the intermixed sequence remains unchanged. These results indicate that telomeric DNA is rather sensitive towards low-energy electron-induced strand breakage suggesting significant telomere shortening that can also occur during cancer radiation therapy.
Asunto(s)
ADN/efectos de la radiación , Telómero/metabolismo , Daño del ADN , Electrones , G-Cuádruplex , Neoplasias/radioterapia , FototerapiaRESUMEN
Track structures and resulting DNA damage in human cells have been simulated for hydrogen, helium, carbon, nitrogen, oxygen and neon ions with 0.25-256 MeV/u energy. The needed ion interaction cross sections have been scaled from those of hydrogen; Barkas scaling formula has been refined, extending its applicability down to about 10 keV/u, and validated against established stopping power data. Linear energy transfer (LET) has been scored from energy deposits in a cell nucleus; for very low-energy ions, it has been defined locally within thin slabs. The simulations show that protons and helium ions induce more DNA damage than heavier ions do at the same LET. With increasing LET, less DNA strand breaks are formed per unit dose, but due to their clustering the yields of double-strand breaks (DSB) increase, up to saturation around 300 keV/µm. Also individual DSB tend to cluster; DSB clusters peak around 500 keV/µm, while DSB multiplicities per cluster steadily increase with LET. Remarkably similar to patterns known from cell survival studies, LET-dependencies with pronounced maxima around 100-200 keV/µm occur on nanometre scale for sites that contain one or more DSB, and on micrometre scale for megabasepair-sized DNA fragments.
Asunto(s)
Roturas del ADN de Doble Cadena , ADN/efectos de la radiación , Luz , Fototerapia/efectos adversos , Protones , Radioterapia/efectos adversos , Carbono/química , Carbono/farmacología , Simulación por Computador , Helio/química , Helio/farmacología , Humanos , Transferencia Lineal de Energía , Neón/química , Oxígeno/química , Oxígeno/farmacologíaRESUMEN
NAD+ is an essential cofactor for enzymes catalyzing redox-reactions as well as an electron carrier in energy metabolism. Aside from this, NAD+ consuming enzymes like poly(ADP-ribose) polymerases and sirtuins are important regulators involved in chromatin-restructuring processes during repair and epigenetics/transcriptional adaption. In order to replenish cellular NAD+ levels after cleavage, synthesis starts from precursors such as nicotinamide, nicotinamide riboside or nicotinic acid to match the need for this essential molecule. In the present study, we investigated the impact of supplementation with nicotinic acid on resting and proliferating human mononuclear blood cells with a focus on DNA damage and repair processes. We observed that nicotinic acid supplementation increased NAD+ levels as well as DNA repair efficiency and enhanced genomic stability evaluated by micronucleus test after x-ray treatment. Interestingly, resting cells displayed lower basal levels of DNA breaks compared to proliferating cells, but break-induction rates were identical. Despite similar levels of p53 protein upregulation after irradiation, higher NAD+ concentrations led to reduced acetylation of this protein, suggesting enhanced SIRT1 activity. Our data reveal that even in normal primary human cells cellular NAD+ levels may be limiting under conditions of genotoxic stress and that boosting the NAD+ system with nicotinic acid can improve genomic stability.
Asunto(s)
Daño del ADN , Reparación del ADN , Leucocitos Mononucleares/metabolismo , NAD/metabolismo , Niacina/metabolismo , Radiación Ionizante , Acetilación , Adulto , ADN/metabolismo , ADN/efectos de la radiación , Suplementos Dietéticos , Humanos , Leucocitos Mononucleares/efectos de la radiación , Persona de Mediana Edad , NAD/análisis , Sirtuinas/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Adulto JovenRESUMEN
DNA-associated Auger electron emitters (AEE) cause cellular damage leading to high-LET type cell survival curves indicating an enhanced relative biological effectiveness. Double strand breaks (DSBs) induced by Iodine-125-deoxyuridine ((125)I-UdR) decays are claimed to be very complex. To elucidate the assumed genotoxic potential of (125)I-UdR, chromatid aberrations were analysed in exposed human peripheral blood lymphocytes (PBL). PBL were stimulated with medium containing phytohaemagglutinin (PHA). After 24h, cultures were labelled with (125)I-UdR for 18h (activity concentration 1-45 kBq) during the S-phase. Following standard cytogenetic procedure, at least 100 metaphases were analysed microscopically for each activity concentration. Cell death was measured by apoptosis assay using flow cytometry. Radiation doses were determined by using point kernel calculations. After 18h labelling with (125)I-UdR the cell cycle distribution is severely disturbed. About 40% of PBL are fully labelled and 20% show a moderate labelling of (125)I-UdR, whereas 40% of cells remain un-labelled. The dose-response relationship fits to a polynomial curve in the low dose range, whereas a linear fit supplies a better estimation in the high dose range. Even the lowest dose of 0.2Gy leads to a 13-fold increase of aberrations compared to the controls. On average every fifth (125)I-decay produces a single chromatid aberration in PBL. Additionally, a dose-dependent increase of cell death is observed. (125)I-UdR has a very strong genotoxic capacity in human PBL, even at 0.2Gy. Efficiently labelled cells displaying a prolonged cell cycle compared to moderately labelled cells and cell death contribute substantially to the desynchronisation of the cell cycle. Our data, showing for the first time, that one (125)I-decay induces â¼ 0.2 chromatid aberrations, are in very good accordance to DSB data, stating that â¼0.26 DSB are induced per decay, indicating that it takes on average 250 decays to induce one chromosome aberration (CA). [Corrected]
Asunto(s)
Aberraciones Cromosómicas , ADN/efectos de la radiación , Radioisótopos de Yodo/farmacocinética , Linfocitos/efectos de la radiación , Técnicas de Cultivo de Célula , Proliferación Celular/efectos de la radiación , Roturas del ADN de Doble Cadena , Relación Dosis-Respuesta en la Radiación , Humanos , Masculino , Efectividad Biológica RelativaRESUMEN
The acute genoprotective effect of Panax quinquefolius (American ginseng) has been investigated. The experiment was carried out to explore the DNA protective effect after a single dose of American ginseng tea bag infusion. Fourteen subjects (6 males and 8 females) were recruited in this study. Seven of them (3 males and 4 females) were asked to drink a cup of freshly prepared American ginseng infusions. Water was taken by the remaining subjects as the control group. Blood samples of both groups were taken before and 2 h post-ingestion. The blood samples were challenged with ultraviolet B irradiation followed by using comet assay. Completed slides were stained with Giemsa stain and DNA damage was assessed. Results showed a significant decrease in comet score after American ginseng supplementation and no change in the control group. The current study demonstrated a cup of American ginseng infusion could protect cellular DNA from oxidative stress at least within 2 h.
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Antioxidantes/farmacología , Daño del ADN , ADN/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Panax/química , Extractos Vegetales/farmacología , Adulto , Ensayo Cometa , ADN/metabolismo , ADN/efectos de la radiación , Femenino , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Fitoterapia , Proyectos Piloto , Rayos Ultravioleta , Adulto JovenRESUMEN
Many authors focused on the research of natural compounds in order to protect skin from indirect (UVA) and direct (UVB) ultraviolet radiation side effects. The aim of this study to evaluate the protective effect of a dry extract from T. vulgaris L. and of its major synthetic compound thymol (about 60%), against oxidative and genotoxic UVA- and UVB damage. Experiments were reproduced in a low differentiated keratinocytes cell line (NCTC 2544) Cells were pretreated for 1h, in serum-free medium, with thymol (1µg/mL) or T. vulgaris L. (1.82µg/mL) then exposed to different UVA (8-24J/cm(2)) or UVB doses (0.016-0.72J/cm(2)). Immediately after the UV exposure the intracellular redox status was evaluated by ROS quantification and by LPO. Genotoxic aspects were evaluated 24h after the end of irradiations using the alkaline comet assay, the micronucleus formation assay and the immunostaining of phosphorylated H2AX histone protein (detected 1h after the end of UV exposure). Thymol and T. vulgaris L. extract inhibited ROS generation in UVA and UVB-irradiated cells. On the contrary, MDA formation was reduced only in UVA treated cells. Both agents decreased the DNA damage evaluated by the alkaline comet assay, but not in the micronucleus and H2AX tests probably because of the severity of damage (double strands) detected.
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Daño del ADN/efectos de los fármacos , Células Epiteliales/efectos de la radiación , Extractos Vegetales/farmacología , Sustancias Protectoras/farmacología , Protectores contra Radiación/farmacología , Timol/farmacología , Thymus (Planta)/química , Línea Celular , Ensayo Cometa , ADN/efectos de la radiación , Células Epiteliales/efectos de los fármacos , Humanos , Peroxidación de Lípido/efectos de los fármacos , Peroxidación de Lípido/efectos de la radiación , Pruebas de Micronúcleos , Extractos Vegetales/química , Protectores contra Radiación/química , Especies Reactivas de Oxígeno/metabolismo , Rayos UltravioletaRESUMEN
Epigenetic modifications by DNA methylation are associated with a wide range of diseases. Previous studies in psoriasis have concentrated on epigenetic changes in immune cells or in total skin biopsies that include stromal-associated changes. In order to improve our understanding of the role of DNA methylation in psoriasis, we sought to obtain a comprehensive DNA methylation signature specific for the epidermal component of psoriasis and to analyze methylation changes during therapy. Genome-wide DNA methylation profiling of epidermal cells from 12 patients undergoing narrow-band UVB phototherapy and 12 corresponding healthy controls revealed a distinct DNA methylation pattern in psoriasis compared with controls. A total of 3,665 methylation variable positions (MVPs) were identified with an overall hypomethylation in psoriasis patient samples. DNA methylation pattern was reversed at the end of phototherapy in patients showing excellent clinical improvement. Only 7% of phototherapy-affected MVPs (150 out of 2,108) correlate with nearby gene expression. Enrichment of MVPs in enhancers indicates tissue-specific modulation of the transcriptional regulatory machinery in psoriasis. Our study identified key epigenetic events associated with psoriasis pathogenesis and helps understand the dynamic DNA methylation landscape in the human genome.
Asunto(s)
Metilación de ADN/efectos de la radiación , Epidermis/efectos de la radiación , Fototerapia , Psoriasis/terapia , Rayos Ultravioleta , Adolescente , Adulto , Anciano , Estudios de Casos y Controles , ADN/metabolismo , ADN/efectos de la radiación , Metilación de ADN/genética , Epidermis/metabolismo , Epidermis/patología , Femenino , Estudio de Asociación del Genoma Completo , Humanos , Masculino , Persona de Mediana Edad , Psoriasis/diagnóstico , Psoriasis/patología , Índice de Severidad de la Enfermedad , Resultado del TratamientoRESUMEN
Bisphenol A (BPA) is a biologically active industrial chemical used in production of consumer products. BPA has become a target of intense public scrutiny following concerns about its association with human diseases such as obesity, diabetes, reproductive disorders, and cancer. Recent studies link BPA with the generation of reactive oxygen species, and base excision repair (BER) is responsible for removing oxidatively induced DNA lesions. Yet, the relationship between BPA and BER has yet to be examined. Further, the ubiquitous nature of BPA allows continuous exposure of the human genome concurrent with the normal endogenous and exogenous insults to the genome, and this co-exposure may impact the DNA damage response and repair. To determine the effect of BPA exposure on base excision repair of oxidatively induced DNA damage, cells compromised in double-strand break repair were treated with BPA alone or co-exposed with either potassium bromate (KBrO3) or laser irradiation as oxidative damaging agents. In experiments with KBrO3, co-treatment with BPA partially reversed the KBrO3-induced cytotoxicity observed in these cells, and this was coincident with an increase in guanine base lesions in genomic DNA. The improvement in cell survival and the increase in oxidatively induced DNA base lesions were reminiscent of previous results with alkyl adenine DNA glycosylase-deficient cells, suggesting that BPA may prevent initiation of repair of oxidized base lesions. With laser irradiation-induced DNA damage, treatment with BPA suppressed DNA repair as revealed by several indicators. These results are consistent with the hypothesis that BPA can induce a suppression of oxidized base lesion DNA repair by the base excision repair pathway.
Asunto(s)
Compuestos de Bencidrilo/efectos adversos , Bromatos/farmacología , Daño del ADN/efectos de los fármacos , Fibroblastos/efectos de los fármacos , Guanina/metabolismo , Fenoles/efectos adversos , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , ADN/efectos de los fármacos , ADN/efectos de la radiación , Reparación del ADN/efectos de los fármacos , Reparación del ADN/efectos de la radiación , Fibroblastos/citología , Fibroblastos/efectos de la radiación , Terapia por Luz de Baja Intensidad/efectos adversos , Ratones , Estrés Oxidativo/efectos de los fármacosRESUMEN
We investigated a phenomenon of ultrasonic cleavage of DNA complexed with transition metal cations Ag(I), Cu(II) and Hg(II). We found the statistically significant dependence of relative intensity of cleavage on cation type and concentration. Each cation may cause two different types of distortion in the DNA double-helix depending on whether it binds to major or minor DNA groove. The intensity of ultrasonic cleavage decreases if cation binds to the major DNA groove; the intensity of cleavage increases if cation binds to the minor DNA groove and disturbs the hydrogen bonds of complementary base pairs or it intercalates between bases. Both types of DNA distortion can affect the intensity of N-S interconversion of deoxyribose.
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Cationes/química , ADN/química , Estructura Molecular , Cobre/química , Cristalografía por Rayos X , ADN/efectos de la radiación , Desoxirribosa/química , Enlace de Hidrógeno/efectos de la radiación , Mercurio/química , Plata/química , SonidoRESUMEN
The radioisotope iodine-131 [(131)I] can damage DNA. One way to prevent this is to increase the amount of antioxidants via dietary consumption. The goal of this study was to evaluate the radioprotective effect of fresh acerola pulp and synthetic beta-carotene in Rattus norvegicus hepatoma cells (HTC) in response to [(131)I] exposure in vitro. Cellular DNA damage was subsequently assessed using a cytokinesis block micronucleus assay. The mutagenic and cytotoxic activities of doses of [(131)I] (0.1, 0.5, 1, 5, and 10 µCi), acerola (0.025, 0.125, and 0.25 g acerola pulp/mL), and beta-carotene (0.2, 1, and 2 µM) were evaluated. Radioprotective tests were performed by simultaneous treatment with acerola (0.25 g/mL) plus [(131)I] (10 µCi) and beta-carotene (0.2 µM) plus [(131)I] (10 µCi). Acerola, beta-carotene, and low concentrations of [(131)I] did not induce micronucleus formation in HTC cells; in contrast, high concentrations of [(131)I] (10 µCi) were mutagenic and induced DNA damage. Moreover, neither acerola nor beta-carotene treatment was cytotoxic. However, acerola reduced the percentage of [(131)I]-induced damage, although beta-carotene did not show a similar effect. Thus, our results suggest that acerola diet supplementation may benefit patients who are exposed to [(131)I] during thyroid diagnostics and therapy.
Asunto(s)
Daño del ADN/efectos de la radiación , Radioisótopos de Yodo/toxicidad , Malpighiaceae/metabolismo , Protectores contra Radiación/farmacología , beta Caroteno/farmacología , Animales , Antocianinas/análisis , Antioxidantes/farmacología , Ácido Ascórbico/análisis , Carcinoma Hepatocelular , Carotenoides/análisis , ADN/efectos de la radiación , Suplementos Dietéticos , Flavonoides/análisis , Radioisótopos de Yodo/farmacología , Neoplasias Hepáticas , Mutación/efectos de la radiación , Preparaciones de Plantas/efectos adversos , Preparaciones de Plantas/farmacología , Ratas , Ratas Wistar , Células Tumorales Cultivadas , beta Caroteno/efectos adversosRESUMEN
Myriad research has contributed significantly toward the understanding and identification of health benefits stemming from tea polyphenols and many other naturally occurring flavonoids present in fruits and vegetables. These flavonoids are known to mitigate reactive oxygen species-induced damage by scavenging them. In this study, hot-water black tea extract rich in flavonoids is evaluated as a supplementary antioxidant. The antioxidant efficacy of black tea extract was investigated by evaluating radioprotection conferred to pBR322 DNA, calf thymus DNA, and normal lymphocytes during gamma irradiation. The protection was measured by gel electrophoresis, fluorimetric study, cell viability assay, cytokinesis-blocked micronuclei assay, and comet assay. The 2,2-diphenyl-1-picrylhydrazyl scavenging ability of the tea extract used increased in a dose-dependent manner (IC50: 182.45 µg/mL). Positive correlation of radioprotection with antioxidant activity of black tea extract was observed in all systems. Maximum protection against radiation-induced damage was observed in pBR322 DNA and calf thymus DNA at ≥200 µg/mL of black tea extract. At a dose of black tea extract as low as 5 µg/mL, efficient radioprotection was observed in normal lymphocytes, which is encouraging and can be tested in the future as a natural antioxidant supplement during radiotherapy.
Asunto(s)
Antioxidantes/farmacología , Daño del ADN/efectos de los fármacos , Daño del ADN/efectos de la radiación , Linfocitos/efectos de los fármacos , Linfocitos/efectos de la radiación , Extractos Vegetales/farmacología , Té , Adulto , Animales , Bovinos , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Ensayo Cometa , Citocinesis/efectos de los fármacos , Citocinesis/efectos de la radiación , ADN/efectos de los fármacos , ADN/efectos de la radiación , Rayos gamma/efectos adversos , Humanos , Técnicas In Vitro , Plásmidos , Protección Radiológica , TimoRESUMEN
Persistent harmful scenarios associated with disposal of radioactive waste, high-background radiation areas and severe nuclear accidents are of great concern regarding consequences to both human health and the environment. Of particular concern is the extracellular DNA in aquatic environments contaminated by radiological substances. Strand breaks induced by radiation promote decrease in the transformation efficiency for extracellular DNA. The focus of this study is the quantification of DNA damage following long-term exposure (over one year) to low doses of natural uranium (an alpha particle emitter) to simulate natural conditions, since nothing is known about alpha radiation induced damage to extracellular DNA. A high-resolution Atomic Force Microscope was used to evaluate DNA fragments. Double-stranded plasmid pBS as a model for extracellular DNA was exposed to different amounts of natural uranium. It was demonstrated that low concentrations of U in water (50 to 150 ppm) produce appreciable numbers of double strand breaks, scaling with the square of the average doses. The importance of these findings for environment monitoring of radiological pollution is addressed.