Induction Of Oxidative DNA Damage Research Articles

Cardiotoxicity and lung toxicity in male rats induced by long-term exposure to iron oxide and silver nanoparticles.

Engineered nanoparticles (NPs) have been increasingly used in numerous fields over the last decade. In particular, iron oxide NPs (Fe2O3NPs) and silver NPs (AgNPs) have contributed to the current increase in NP usage. However, the possible side effects of increased NP exposure remain not fully elucidated. The present study aimed to assess the toxic effects of Fe2O3NPs and AgNPs, both individually and in combination, on the heart and lungs of male rats. To evaluate the in vivo NP toxic effects, the experimental animals were orally administered with Fe2O3NPs (5 mg/kg) and/or AgNPs (50 mg/kg). Animals were treated every day for 79 days. The results demonstrated that at the molecular level, Fe2O3NPs and AgNPs caused marked DNA base oxidation as indicated by the elevated DNA content of 8-hydroxy-2−deoxyguanosine in the heart and lungs. Fe2O3NPs and/or AgNPs decreased paraoxonase 1, antioxidant enzymes, total antioxidant capacity, and reduced glutathione in heart and lung. A dose-dependent increase in production of creatine kinase, thiobarbituric acid-reactive substances, nitric oxide end products, tumor necrosis factor-α, interleukin-6 and lipid profiles was detected. Histological changes were also evident in heart and lung tissues. The two NPs demonstrated similar toxic effects for the majority of factors when co-supplemented. In conclusion, the present study identified that Fe2O3NPs and AgNPs, alone and in combination, induced cardiotoxicity and lung toxicity. Furthermore, findings demonstrated that there was a greater toxic effect due to administration of both NPs compared to individual administration. It was hypothesized that the toxic effects may be mediated through the induction of oxidative DNA damage, lipid peroxidation, shifting redox status, disrupted gene expression, and deregulation in cytokine production.

Seasonal dependence of cadmium molecular effects on Mytilus galloprovincialis (Lamarck, 1819) protamine-like protein properties.

Mussels have a seasonal reproduction and cadmium is a common stressor in estuarine and coastal environments. In previous studies, we have shown that exposure to subtoxic doses of cadmium produced alterations in the properties of winter Mytilus galloprovincialis sperm protamine-like (PL) proteins. In this study, it was analyzed the possibility that these cadmium effects may be seasonal. Winter and summer mussels were exposed to CdCl2 , and it was tested the PL-proteins for cadmium bioaccumulation, electrophoretic pattern, DNA binding, and potentiality to induce DNA oxidative damage. It was found that cadmium exposure did not produce the same effects on PL-proteins of summer mussels that were produced on PL-proteins of winter mussels, that is: cadmium bioaccumulation, alterations in the acetic acid-urea polyacrylamide gels (AU-PAGE) and sodium dodecyl sulfate-PAGE pattern, a reduced DNA binding affinity and the ability to induce DNA oxidative damage. PL-proteins from summer mussels, apart from not being affected by all the abovementioned effects of cadmium, also showed a very low DNA binding affinity, independent of cadmium exposure. This study reveals clock-associated seasonal responses to cadmium in M. galloprovincialis. Understanding the mechanisms through which environmental signals guide biological rhythms is fundamental to understanding the seasonal sensitivity of this bioindicator, to use M. galloprovincialis in appropriate seasonal periods.

Organophosphate flame retardants (OPFRs) induce genotoxicity in vivo: A survey on apoptosis, DNA methylation, DNA oxidative damage, liver metabolites, and transcriptomics

BackgroundAs potential substitutes for polybrominated diphenyl ethers (PBDEs), organophosphate flame retardants (OPFRs) have been frequently detected in the environment. However, the genotoxicity induced by these OPFRs has rarely been described, and the results reported in previous studies are conflicting and inconsistent. ObjectivesThe present study aimed to determine how OPFRs induced genetic toxicity in vivo. MethodsUsing Chinese rare minnow as a model, the toxicity of three OPFRs was screened with RNA-seq. To verify the OPFR-induced genotoxicity, alkaline comet assay, cell apoptosis analysis, HPLC-based DNA methylation assay, 8-OHdG assay, bioconcentration and biotransformation investigation were performed. ResultsAccording to transcriptomic data, TDCIPP exposure substantially altered the pathways related to DNA damage, including the cell cycle, DNA replication, Fanconi anemia pathway, p53 signaling pathway, and various DNA repair pathways. Although TBOEP and TPHP did not affect DNA damage, TDCIPP induced DNA damage in a dose-dependent manner. TDCIPP also induced apoptosis, altered the activities of caspase-3 and -9, and increased the 8-OHdG levels, while a significant difference in the levels of DNA methylation induced by OPFRs was not observed. ConclusionsBased on these results, TDCIPP induced DNA oxidative damage, eventually leading to genotoxicity in vivo.

Genotoxicity Evaluation of the Soybean Isoflavone Genistein in Human Papillary Thyroid Cancer Cells. Study of Its Potential Use in Thyroid Cancer Therapy

Genistein is one of the several known isoflavonic phytoestrogens found in a number of plants, with soybeans and soy products being the primary food source. The aim of the study is to evaluate if genistein is able to exert antineoplastic action in primary human papillary thyroid cancer (PTC) cells. Thyroid tissues were treated with genistein (1–10–50–100 µM). Cell viability, proliferation, DNA primary damage and chromosomal damage were evaluated. An antiproliferative effect was induced by the highest doses of genistein, and such an effect was synergistically enhanced by the cotreatment with the antineoplastic drug sorafenib. Comet assay did not show any genotoxic effect in terms of primary DNA damage at all the times (4 and 24 h) and tested doses. A reduction of hydrogen peroxide-induced DNA primary damage in primary thyrocytes from PTC cells pretreated with genistein was observed. Data suggest that genistein exerts antineoplastic action, does not induce genotoxic effects while reduces oxidative-induced DNA damage in primary thyrocytes from PTC cells, supporting its possible use in therapeutic intervention.

Novel first-in-class small molecule targeting APE1/Ref-1 to prevent and treat chemotherapy-induced peripheral neuropathy (CIPN).

229 Background: Chemotherapy-induced peripheral neuropathy (CIPN) is an acute and chronic debilitating side effect of a number of chemotherapeutic agents lacking FDA-approved interventions or strategies resulting in dose-limiting neurotoxicity. CIPN can persist following discontinuation of the drug with up to 40% of patients having continued CIPN five years after treatment ends. Thus, CIPN directly affects cancer survivorship, quality of life, and may limit future treatment options if cancer recurs. Although the cellular mechanisms mediating CIPN remain to be determined, several lines of evidence support the notion that DNA damage caused by anticancer therapies could contribute to the neuropathy. Methods: Using an experimental model of isolated sensory neurons in culture, we established a causal relationship between cancer-therapy-induced neurotoxicity and DNA damage and repair. Results: Genetically reducing the activity of APE1 increased the neurotoxicity produced by platin treatment, whereas augmenting the activity of APE1 lessened neurotoxicity. Furthermore, using a targeted small-molecule, APX3330, which increases DNA repair of APE1 in neurons, it lessened neurotoxicity using a variety of endpoints ex vivo; e.g. DNA damage, CGRP release. We will present data using animal models of CIPN demonstrating a protective effect of APX3330 using either cis- or oxaliplatin without diminishing the anti-tumor effect of the platins. A Phase 1 clinical trial for safety/RF2D for APX3330 has completed (NCT03375086). Conclusions: Effective prevention and management of CIPN hinges on understanding its pathophysiology. While multiple causal mechanisms may be at work, we believe that the induction of oxidative DNA damage in sensory neurons is a major cause of CIPN. Thus, enhancement of oxidative DNA damage repair by APX3330 results in reduction of CIPN.

Assessment of oxidative damage induced by iron oxide nanoparticles on different nervous system cells

Iron oxide nanoparticles (ION) have received much attention for their utility in biomedical applications, such as magnetic resonance imaging, drug delivery and hyperthermia, but concerns regarding their potential harmful effects are also growing. Even though ION may induce different toxic effects in a wide variety of cell types and animal systems, there is a notable lack of toxicological data on the human nervous system, particularly important given the increasing number of applications on this specific system. An important mechanism of nanotoxicity is reactive oxygen species (ROS) generation and oxidative stress. On this basis, the main objective of this work was to assess the oxidative potential of silica-coated (S-ION) and oleic acid-coated (O-ION) ION on human SH-SY5Y neuronal and A172 glial cells. To this aim, ability of ION to generate ROS (both in the absence and presence of cells) was determined, and consequences of oxidative potential were assessed (i) on DNA by means of the 8-oxo-7,8-dihydroguanine DNA glycosylase (OGG1)-modified comet assay, and (ii) on antioxidant reserves by analyzing ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG). Conditions tested included a range of concentrations, two exposure times (3 and 24 h), and absence and presence of serum in the cell culture media. Results confirmed that, even though ION were not able to produce ROS in acellular environments, ROS formation was increased in the neuronal and glial cells by ION exposure, and was parallel to induction of oxidative DNA damage and, only in the case of neuronal cells treated with S-ION, to decreases in the GSH/GSSG ratio. Present findings suggest the production of oxidative stress as a potential action mechanism leading to the previously reported cellular effects, and indicate that ION may pose a health risk to human nervous system cells by generating oxidative stress, and thus should be used with caution.

Probing the Origins of 1,800 MHz Radio Frequency Electromagnetic Radiation Induced Damage in Mouse Immortalized Germ Cells and Spermatozoa in vitro.

As the use of mobile phone devices is now highly prevalent, many studies have sought to evaluate the effects of the radiofrequency-electromagnetic radiation (RF-EMR) on both human health and biology. While several such studies have shown RF-EMR is capable of inducing cellular stress, the physicobiological origin of this stress remains largely unresolved. To explore the effect of RF-EMR on the male reproductive system, we exposed cultured mouse spermatogonial GC1 and spermatocyte GC2 cell lines, as well as cauda epididymal spermatozoa to a waveguide generating continuous wave RF-EMR (1.8 GHz, 0.15 and 1.5 W/kg). This study demonstrated that a 4 h exposure is capable of inducing the generation of mitochondrial reactive oxygen species (ROS) in populations of GC1 (7 vs. 18%; p < 0.001) and GC2 cells (11.5 vs. 16 %; p < 0.01), identifying Complex III of the electron transport chain (ETC) as the potential source of electrons producing ROS. Assessing the generation of ROS in the presence of an antioxidant, penicillamine, as well as measuring lipid peroxidation via 4-hydroxynonenal levels, indicated that the elevated incidence of ROS generation observed under our exposure conditions did not necessarily induce an overt cellular oxidative stress response. However, exposure to RF-EMR at 0.15 W/kg for 3 h did induce significant DNA fragmentation in spermatozoa (that was no longer significant after 4 h), assessed by the alkaline comet assay (p < 0.05). Furthermore, this fragmentation was accompanied by an induction of oxidative DNA damage in the form of 8-hydroxy-2′-deoxyguanosine, which was significant (p < 0.05) after spermatozoa were exposed to RF-EMR for 4 h. At this exposure time point, a decline in sperm motility (p < 0.05) was also observed. This study contributes new evidence toward elucidating a mechanism to account for the effects of RF-EMR on biological systems, proposing Complex III of the mitochondrial ETC as the key target of this radiation.

Induction of Oxidative DNA Damage in Bovine Herpesvirus 1 Infected Bovine Kidney Cells (MDBK Cells) and Human Tumor Cells (A549 Cells and U2OS Cells).

Bovine herpesvirus 1 (BoHV-1) is an important pathogen of cattle that causes lesions in mucosal surfaces, genital tracts and nervous systems. As a novel oncolytic virus, BoHV-1 infects and kills numerous human tumor cells. However, the mechanisms underlying the virus-induced cell damages are not fully understood. In this study, we demonstrated that virus infection of MDBK cells induced high levels of DNA damage, because the percentage of comet tail DNA (tailDNA%) determined by comet assay, a direct indicator of DNA damage, and the levels of 8-hydroxyguanine (8-oxoG) production, an oxidative DNA damage marker, consistently increased following the virus infection. The expression of 8-oxoguanine DNA glycosylase (OGG-1), an enzyme responsible for the excision of 8-oxoG, was significantly decreased due to the virus infection, which corroborated with the finding that BoHV-1 infection stimulated 8-oxoG production. Furthermore, the virus replication in human tumor cells such as in A549 cells and U2OS cells also induced DNA damage. Chemical inhibition of reactive oxidative species (ROS) production by either ROS scavenger N-Acetyl-l-cysteine or NOX inhibitor diphenylene iodonium (DPI) significantly decreased the levels of tailDNA%, suggesting the involvement of ROS in the virus induced DNA lesions. Collectively, these results indicated that BoHV-1 infection of these cells elicits oxidative DNA damages, providing a perspective in understanding the mechanisms by which the virus induces cell death in both native host cells and human tumor cells.

Effect of methylglyoxal on reactive oxygen species, KI-67, and caspase-3 expression in MCF-7 cells

BackgroundMethylglyoxal (MG) is an extremely reactive α-ketoaldehyde endogenously produced by various metabolic pathways, including the dephosphorylation of glycolytic intermediates, metabolites of the polyol pathway, and aminoacetone metabolism. MG cytotoxicity occurs through the induction of apoptosis. There are multiple mechanisms by which MG can induce apoptosis, e.g., through the generation of reactive oxygen species (ROS), induction of oxidative DNA damage, or accumulation of a specific MG-derived advanced glycation end product (AGE). ObjectiveThis study aimed to investigate the effect of MG on ROS production, KI-67 expression, and caspase-3 expression in MCF-7 cells. MethodsAt confluency, MCF-7 cells were divided into five groups, including control (untreated); and MCF-7 cells exposed to MG (1 mM) for 0; 12; 24; and 48 h of incubation. Reactive oxygen species level, KI-67 expression, and caspase-3 expression were evaluated by laser scanning confocal microscopy. ResultsThe level of reactive oxygen species was significantly lower in 12 h of incubation compared to the control group (p < .05). The reactive oxygen species level was significantly higher in 48 h of incubation compared to the control group (p < .05). The expressions of KI-67 was significantly higher in all groups of MCF-7 cells treated with MG compared to the control group (p < .05). The maximal expression of KI-67 was achieved in 12 h of incubation. The expression of KI-67 was significantly lower in 48 h of incubation compared to 12 h of incubation (p < .05). The caspase-3 expressions were significantly greater in all groups of MCF-7 cells treated with MG groups compared to the control group (p < .05). The maximal expression of caspase-3 was achieved in 48 h of incubation. The increased expression of caspase-3 in 48 h of incubation was significantly higher compared to 0; 12; and 24 h of incubation (p < .05). ConclusionMethylglyoxal at 48 h of incubation disturbs the defense mechanisms of MCF-7 cells to reactive oxygen species. This incubation time also induces apoptosis and inhibits the cells proliferation. Therefore, this may provide a novel approach for inhibiting the breast cancer cell growth.

Influence of acute ingestion and regular intake of green tea catechins on resting oxidative stress biomarkers assays in a paralleled randomized controlled crossover supplementation study in healthy men

In this paralleled randomized controlled crossover study, we examined the hypothesis whether acute or regular green tea catechins (GTC) supplements have the potential to stimulate resting oxidative stress metabolites in healthy individuals. Sixteen subjects were randomly divided equally and assigned into regular intake (GTC-RI) or control group (GTC-CG) after the screening. GTC-RI group consumed 780 mg/day EGCG-enriched GTC (506 mg EGCG). While GTC-CG received water under the identical diet regime and lifestyle conditions. Then the GTC-CG crossed over to acute intake (GTC-AI) group and consumed a single dose of 780 mg ECGC-enriched GTC. Blood aliquots were collected at baseline and after GTC ingestion according to the prescribed study protocol. We measured oxidative stress blood biomarkers using the diacron reactive oxygen metabolite (d-ROMs) and biological antioxidant potential (BAP) tests. Urinary 8-hydroxydeoxyguanosine (8-OHdG) and 8-OHdG/creatinine were also analyzed. Analysis of variance (ANOVA) was used to determine statistical significance (P < 0.05) within the group as well as between and among the groups. The relative ratio of BAP and 8-OHdG concentrations to baseline showed statistical significance (P < 0.05) between the GTC-AI and GTC-RI groups and among all groups as determined by two-way repeated measures factorial ANOVA. The present results support the importance of appropriate GTC intake as antioxidant supplements for reducing oxidative stress that might lead to a sedentary behavior under resting conditions. Regular intake of GTC offers protection against oxidation-induced DNA damage in healthy humans and decreased oxidative stress. When GTC is taken in safe dosages under acceptable limits they reduce oxidative stress via associated and/or unassociated oxidant effect without any relevant pro-oxidant activity related to redox-sensitive adaptations.

Oxidatively-induced DNA damage and base excision repair in euthymic patients with bipolar disorder

Oxidatively-induced DNA damage has previously been associated with bipolar disorder. More recently, impairments in DNA repair mechanisms have also been reported. We aimed to investigate oxidatively-induced DNA lesions and expression of DNA glycosylases involved in base excision repair in euthymic patients with bipolar disorder compared to healthy individuals. DNA base lesions including both base and nucleoside modifications were measured using gas chromatography-tandem mass spectrometry and liquid chromatography-tandem mass spectrometry with isotope-dilution in DNA samples isolated from leukocytes of euthymic patients with bipolar disorder (n = 32) and healthy individuals (n = 51). The expression of DNA repair enzymes OGG1 and NEIL1 were measured using quantitative real-time polymerase chain reaction. The levels of malondialdehyde were measured using high performance liquid chromatography. Seven DNA base lesions in DNA of leukocytes of patients and healthy individuals were identified and quantified. Three of them had significantly elevated levels in bipolar patients when compared to healthy individuals. No elevation of lipid peroxidation marker malondialdehyde was observed. The level of OGG1 expression was significantly reduced in bipolar patients compared to healthy individuals, whereas the two groups exhibited similar levels of NEIL1 expression. Our results suggest that oxidatively-induced DNA damage occurs and base excision repair capacity may be decreased in bipolar patients when compared to healthy individuals. Measurement of oxidatively-induced DNA base lesions and the expression of DNA repair enzymes may be of great importance for large scale basic research and clinical studies of bipolar disorder.

In ovo testing of flavor and fragrance materials in Turkey Egg Genotoxicity Assay (TEGA), comparison of results to in vitro and in vivo data

Genotoxicity of flavor and fragrance materials was assessed in Turkey Egg Genotoxicity Assay (TEGA) using 32P-nucleotide postlabeling (NPL) and comet assays to detect hepatic DNA adducts and strand breaks. Twenty materials having results in GADD45a-Gluc ‘BlueScreen HC’ genotoxicity assay, and standard in vitro and in vivo tests, were selected to evaluate the accuracy of TEGA. Quinoline (QUI) and 2-acetylaminofluorene (AAF) served as positive comparators.Two materials, p-tert-butyldihydrocinnamaldehyde (BDHCA) and methyl eugenol (MEU) produced DNA adducts. BDHCA, p-t-butyl-α-methylhydrocinnamic aldehyde (BMHCA), trans-2-hexenal (HEX) and maltol (MAL) produced DNA strand breaks. Fifteen other materials were negative in both assays. Based on reports of oxidative DNA damage induction by MAL and 4-hydroxy-2.5-dimethyl-3(2H) furanone (HDMF), modified comet assays were conducted. Positive comet findings for MAL were not confirmed, and only equivocal evidence of oxidative damage was found. Accordingly, MAL was judged to have equivocal genotoxicity in TEGA. HDMF was positive in modified comet assay, indicating an ability to produce oxidative DNA damage.TEGA showed modest concordance with results in regulatory in vitro assays. Findings in TEGA, with few exceptions, were concordant with the results of in vivo genotoxicity and carcinogenicity testing. Thus, TEGA is an attractive alternative model for the assessment of genotoxic potential of chemicals in vivo.

Quantification of DNA damage products by gas chromatography tandem mass spectrometry in lung cell lines and prevention effect of thyme antioxidants on oxidative induced DNA damage

Lung cancer has a high treatment cost and poor prognosis in comparison to other types of cancers. This work was involved in studying oxidative DNA base damage inhibition. Accordingly, standard carvacrol, thymol, thymoquinone with water and water-methanol extract of thyme (Origanum vulgare L. subsp. hirtum (link.) Ietswaart), thyme oil and thyme water were prepared and investigated for their efficacy to inhibit DNA oxidative damage formed by H2O2 in malignant lung cells (A549). The antioxidant capacity by ABTS assay was 271.73 ± 11.45 mg trolox equivalent/mL for thyme oil. HPLC analysis was carried out to determine the contents of different thyme extracts, results showing the presence of carvacrol, thymol, protocatechuic acid, caffeic acid, epicatechin and rosmarinic acid in water and water-methanol extracts while only carvacrol and thymol were found in thyme oil and thyme water. After DNA isolation from the cultured cells, the formed oxidative induced DNA damage products were analysed using GC–MS/MS. It was proven that the antioxidants in the cell culture media have succeeded to inhibit oxidative DNA base damage. Thymoquinone was shown to be the best protectant antioxidant among other antioxidants against the formation of oxidative DNA damage, whereas water-methanol extract of thyme was the best among the plant-sourced samples. Thymoquinone and thyme water-methanol extract were investigated for their efficacy on cultured healthy lung cells (BEAS-2B), and it was proven that they are efficient in protection against the oxidation of DNA of healthy lung cells too.

Does Fluoroscopy Induce DNA Oxidative Damage in Patients Undergoing Catheter Ablation?

As no studies before now have thoroughly investigated the risk associated with the exposure to low-dose ionizing radiations in patients undergoing catheter ablation (CA), we aimed to evaluate the oxidative and DNA damage in 59 CA patients (10 of whom received N-acetylcysteine (NAC) before the procedure). A burst of oxidized/reduced glutathione ratio was observed 3 hours after procedure that was diminished by NAC administration. 8-Hydroxy-2'-deoxyguanosine (8-OHdG) concentrations, index of oxidative DNA damage, showed a peak 24 hours after CA. A positive correlation between 8-OHdG peak and fluoroscopy time and a negative correlation among 8-OHdG decrease (from the peak to 48 hours after CA) and all procedure parameters were found. Furthermore, DNA tail percentages (which reflect the extent and the number of DNA strand breaks) positively correlated with 8-OHdG concentrations. This study evaluates for the first time the kinetic of oxidative damage in patients undergoing CA procedure. Our findings raise the question of whether 8-OHdG can be used as a circulating biomarker of DNA oxidative damage induced by low-dose ionizing radiations in different clinical settings. Antioxid. Redox Signal. 28, 1137-1143.

Paternal Exposure to Environmental Chemical Stress Affects Male Offspring's Hepatic Mitochondria.

Preconceptional paternal exposures may affect offspring's health, which cannot be explained by mutations in germ cells, but by persistent changes in the regulation of gene expression. Therefore, we investigated whether pre-conceptional paternal exposure to benzo[a]pyrene (B[a]P) could alter the offspring's phenotype. Male C57BL/6 mice were exposed to B[a]P by gavage for 6 weeks, 3× per week, and were crossed with unexposed BALB-c females 6 weeks after the final exposure. The offspring was kept under normal feeding conditions and was sacrificed at 3 weeks of age. Analysis of the liver proteome by 2D-gel electrophoresis and mass spectrometry indicated that proteins involved in mitochondrial function were significantly downregulated in the offspring of exposed fathers. This down-regulation of mitochondrial proteins was paralleled by a reduction in mitochondrial DNA copy number and reduced activity of citrate synthase and β-hydroxyacyl-CoA dehydrogenase, but in male offspring only. Surprisingly, analysis of hepatic mRNA expression revealed a male-specific up-regulation of the genes, whose proteins were downregulated, including Aldh2 and Ogg1. This discrepancy could be related to several selected microRNA (miRNA)'s that regulate the translation of these proteins; miRNA-122, miRNA-129-2-5p, and miRNA-1941 were upregulated in a gender-specific manner. Since mitochondria are thought to be a source of intracellular reactive oxygen species, we additionally assessed oxidatively-induced DNA damage. Both 8-hydroxy-deoxyguanosine and malondialdehyde-dG adduct levels were significantly reduced in male offspring of exposed fathers. In conclusion, we show that paternal exposure to B[a]P can regulate mitochondrial metabolism in offspring, which may have profound implications for our understanding of health and disease risk inherited from fathers.

Sanguinarine is reduced by NADH through a covalent adduct

Sanguinarine is a benzo[c]phenanthridine alkaloid with interesting cytotoxic properties, such as induction of oxidative DNA damage and very rapid apoptosis, which is not mediated by p53-dependent signaling. It has been previously documented that sanguinarine is reduced with NADH even in absence of any enzymes while being converted to its dihydro form. We found that the dark blue fluorescent species, observed during sanguinarine reduction with NADH and misinterpreted by Matkar et al. (Arch. Biochem. Biophys. 2008, 477, 43–52) as an anionic form of the alkaloid, is a covalent adduct formed by the interaction of NADH and sanguinarine. The covalent adduct is then converted slowly to the products, dihydrosanguinarine and NAD+, in the second step of reduction. The product of the reduction, dihydrosanguinarine, was continually re-oxidized by the atmospheric oxygen back to sanguinarine, resulting in further reacting with NADH and eventually depleting all NADH molecules. The ability of sanguinarine to diminish the pool of NADH and NADPH is further considered when explaining the sanguinarine-induced apoptosis in living cells.

Mitochondrial Dysfunction and Redox Imbalance as a Diagnostic Marker of "Free Radical Diseases".

The intracellular redox balance (redox status) is a dynamic system that may change via many factors. Mitochondria are one of the most important among them. These organelles are the main intracellular source of energy. They are essential for maintaining cellular homeostasis due to regulation of many biochemical processes. The mitochondrial dynamics change during cellular activities and in some cases, can cause an overproduction of reactive oxygen species (ROS), which encourages the induction of oxidative DNA damage and up- or down-regulation of phosphatases, proliferative/anti-proliferative factors, apoptotic/anti-apoptotic factors, etc. Moreover, mitochondrial dysfunction and redox imbalance can continuously support and contribute to a wide range of pathologies, termed as "free radical diseases" (e.g., cancer, neurodegeneration, atherosclerosis, inflammation, etc.). This review article is focused on the mitochondrial dysfunction and cellular redox status as a hallmark of cell homeostasis and diagnostic marker of cancer. It is intended to broad readership - from students to specialists in the field.

Genotoxic potential of diesel exhaust particles from the combustion of first- and second-generation biodiesel fuels\u2014the FuelHealth project

Epidemiological data indicate that exposure to diesel exhaust particles (DEPs) from traffic emissions is associated with higher risk of morbidity and mortality related to cardiovascular and pulmonary diseases, accelerated progression of atherosclerotic plaques, and possible lung cancer. While the impact of DEPs from combustion of fossil diesel fuel on human health has been extensively studied, current knowledge of DEPs from combustion of biofuels provides limited and inconsistent information about its mutagenicity and genotoxicity, as well as possible adverse health risks. The objective of the present work was to compare the genotoxicity of DEPs from combustion of two first-generation fuels, 7% fatty acid methyl esters (FAME) (B7) and 20% FAME (B20), and a second-generation 20% FAME/hydrotreated vegetable oil (SHB: synthetic hydrocarbon biofuel) fuel. Our results revealed that particulate engine emissions from each type of biodiesel fuel induced genotoxic effects in BEAS-2B and A549 cells, manifested as the increased levels of single-strand breaks, the increased frequencies of micronuclei, or the deregulated expression of genes involved in DNA damage signaling pathways. We also found that none of the tested DEPs showed the induction of oxidative DNA damage and the gamma-H2AX-detectable double-strand breaks. The most pronounced differences concerning the tested particles were observed for the induction of single-strand breaks, with the greatest genotoxicity being associated with the B7-derived DEPs. The differences in other effects between DEPs from the different biodiesel blend percentage and biodiesel feedstock were also observed, but the magnitude of these variations was limited.

P 025 - Oxidative damage, antioxidant defense and DNA repair capacity in patients with Primary Dyslipidemia

Introduction Primary Dyslipidemia is a group of genetic disorders of lipid metabolism. Biomolecules oxidative damage has been reported in those patients, although DNA repair capacity is less reported. The aim of this work is evaluate oxidative stress biomarkers and DNA repair capacity in dyslipidemic patients. Material and Methods Plasma levels of malondialdehyde, advanced oxidation products of proteins and GSH, as well as the activities of SOD1, catalase, glutathione peroxidase and glutathione reductase were measured in patients from a Hospital in Havana. Comet assay was used to evaluate single strand breaks, oxidation-induced DNA damage, and repair capacity in isolated lymphocytes. Results Levels of plasma MDA and GSH were higher in patients, as well as the enzymatic activity of GPx and GR. However, CAT and SOD1 activities did not significantly differ between patients and healthy controls. Additionally, no differences in DNA damage were observed between groups, but DNA repair capacity was significantly slower in patients, mainly in patients with Familiar Hypercholesterolemia (FH). Combined Hyperlipoproteinemia patients showed normal DNA repair. Conclusions These findings show alterations in biomarkers of oxidative stress in patients. The deficiencies in the repair mechanisms could be related with the clinic evolution and the severity of complications in patients with FH.

Chicken egg fetal liver DNA and histopathologic effects of structurally diverse carcinogens and non-carcinogens

Chicken egg fetal livers were evaluated for histopathological changes produced by four genotoxic hepatocarcinogens: 2-acetylaminofluorene (AAF), aflatoxin B1 (AFB1), benzo[a]pyrene (BaP), diethylnitrosamine (DEN); four structurally related non- or weakly- carcinogenic comparators: fluorene (FLU), aflatoxin B2 (AFB2), benzo[e]pyrene (BeP), N-nitrosodiethanolamine (NDELA); two epigenetic hepatocarcinogens: clofibric acid (CFA), phenobarbital (PB); and the non-carcinogen, D-mannitol (MAN). CFA, PB and MAN were also assessed for formation of DNA adducts using the 32P nucleotide postlabeling (NPL) assay and for DNA breaks using the comet assay. CFA was also assessed in enhanced comet assay for oxidative DNA damage induction. Eggs were dosed on days 9- 11 of incubation. For genotoxicity evaluation, livers were collected 3h after the last dose. Liver qualitative histopathology assessment was performed on days 12 and 18 of incubation. CFA was negative for DNA adducts but yielded clear evidence of DNA breaks due to oxidative stress. PB and MAN produced no DNA adducts or breaks. Liver to body weight ratios were not affected in most groups, but were decreased in DEN groups, and increased after PB dosing. Livers from control groups, FLU, AFB2, BeP, NDELA, CFA, and MAN groups, displayed a typical hepatocellular trabecular pattern at both time points. In contrast, the four genotoxic carcinogens induced time- and dose- related interference with fetal liver cell processes of proliferation, migration and differentiation, leading to hepatocellular and cholangiocellular pleomorphic dysplasia and re-(de-) differentiation with distortion of the trabecular pattern. In addition, dosing with the high dose of DEN produced gallbladder agenesis. PB induced hepatocellular hypertrophy, interference with migration, expressed as distortion of the trabecular pattern, and a moderate cholangiocellular dysplasia. In summary, histopathological analysis of chicken fetal livers revealed developmental anomalies, as well as genotoxicity-induced and, in the case of PB, adaptive morphological changes. Thus, the model provides histopathological outcomes of molecular effects.