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1.
Dry olive leaf extract attenuates DNA damage induced by estradiol and diethylstilbestrol in human peripheral blood cells in vitro.
Topalović, D, Dekanski, D, Spremo-Potparević, B, Pirković, A, Borozan, S, Bajić, V, Stojanović, D, Giampieri, F, Gasparrini, M, Živković, L
Mutation research. Genetic toxicology and environmental mutagenesis. 2019;:402993
Abstract
Phenolic groups of steroidal or nonsteroidal estrogens can redox cycle, leading to oxidative stress, where creation of reactive oxygen species are recognized as the main mechanism of their DNA damage properties. Dry olive (Olea europaea L.) leaf extract is known to contain bioactive and antioxidative components and to have an ability to modulate the effects of various oxidants in cells. The main goal of this study was to investigate antigenotoxic potential of a standardized dry olive leaf extract on DNA damage induced by 17β-estradiol and diethylstilbestrol in human whole blood cells in vitro, using comet assay. Our results indicated that both hormones showed a genotoxic effect at a concentration of 100 μM (P < 0.05, n = 6). Dry olive leaf extract was efficient in reducing number of cells with estrogen-induced DNA damage at tested concentrations (0.125, 0.5 and 1 mg/mL) (P < 0.05, n = 6) and under two experimental protocols, pre-treatment and post-treatment, exhibiting antigenotoxic properties. Analysis of antioxidant properties of the extract revealed moderate ABTS radical scavenging properties and reducing power. Overall, our results suggested that the protective potential of dry olive leaf extract could arise from the synergistic effect of its scavenging activity and enhancement of the cells' antioxidant capacity.
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2.
Deferasirox reduces oxidative DNA damage in bone marrow cells from myelodysplastic patients and improves their differentiation capacity.
Jiménez-Solas, T, López-Cadenas, F, Aires-Mejía, I, Caballero-Berrocal, JC, Ortega, R, Redondo, AM, Sánchez-Guijo, F, Muntión, S, García-Martín, L, Albarrán, B, et al
British journal of haematology. 2019;(1):93-104
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Abstract
Patients with low-risk myelodysplastic syndromes (MDS) usually develop iron overload. This leads to a high level of oxidative stress in the bone marrow (BM) and increases haematopoietic cell dysfunction. Our objective was to analyse whether chelation with deferasirox (DFX) alleviates the consequences of oxidative stress and improves BM cell functionality. We analysed 13 iron-overloaded MDS patients' samples before and 4-10 months after treatment with DFX. Using multiparametric flow cytometry analysis, we measured intracellular reactive oxygen species (ROS), DNA oxidation and double strand breaks. Haematopoietic differentiation capacity was analysed by colony-forming unit (CFU) assays. Compared to healthy donors, MDS showed a higher level of intracellular ROS and DNA oxidative damage in BM cells. DNA oxidative damage decreased following DFX treatment. Furthermore, the clonogenic assays carried out before treatment suggest an impaired haematopoietic differentiation. DFX seems to improve this capacity, as illustrated by a decreased cluster/CFU ratio, which reached values similar to controls. We conclude that BM cells from MDS are subject to higher oxidative stress conditions and show an impaired haematopoietic differentiation. These adverse features seem to be partially rectified after DFX treatment.
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Prevention by L-carnitine of DNA damage induced by 3-hydroxy-3-methylglutaric and 3-methylglutaric acids and experimental evidence of lipid and DNA damage in patients with 3-hydroxy-3-methylglutaric aciduria.
Delgado, CA, Balbueno Guerreiro, GB, Diaz Jacques, CE, de Moura Coelho, D, Sitta, A, Manfredini, V, Wajner, M, Vargas, CR
Archives of biochemistry and biophysics. 2019;:16-22
Abstract
3-hydroxy-3-methylglutaric aciduria (HMGA) is an inherited disorder of the leucine catabolic pathway in which occurs a deficiency of the 3-hydroxy-3-methylglutaryl-CoA lyase enzyme. Therefore, the organic acids 3-hydroxy-3-methylglutaric (HMG) and 3-methylglutaric (MGA), mainly, accumulate in tissues of affected patients. Lately, much attention has been focused on free radicals as mediators of tissue damage in human diseases, causing lipid peroxidation, protein oxidation and DNA damage. The treatment of this disease is based in a restricted protein ingest and supplementation with l-carnitine (LC), an antioxidant and detoxifying agent. In the present work, we investigated the in vitro oxidative damage to DNA induced by the accumulation of organic acids and oxidative stress parameters in vivo of patients with 3-HMG, as well as the effect of the recommended therapy. The in vitro DNA damage was analyzed by the alkaline comet assay in leukocytes incubated with HMG and MGA (1 mM, 2.5 mM and 5 mM) and co-incubated with LC (90 μM and 150 μM). The in vivo urinary 15-F2t-isoprostane levels and urinary oxidized guanine species were measured by ELISA kits in patient's urine before and after the treatment with LC. HMG and MGA induced a DNA damage index (DI) significantly higher than that of the control group. The DI was significantly reduced in the presence of LC. It was also verified a significant increase of oxidized guanine species and urinary isoprostane levels, biomarker of oxidative DNA damage and lipid peroxidation respectively, in patients before treatment. After the treatment and supplementation with LC, patients presented significantly lower levels of those biomarkers. Analyzing the data together, we can conclude that HMGA patients present oxidative lipid and DNA damage, which is induced by HMG and MGA, and the antioxidant therapy with LC can prevent that kind of injuries.
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Hydrogen peroxide, a potent inducer of global genomic instability.
Qi, L, Wu, XC, Zheng, DQ
Current genetics. 2019;(4):913-917
Abstract
Oxidative stress has been implicated in a variety of human diseases. One plausible mechanism is that reactive active species can induce DNA damages and jeopardize genome integrity. To explore how oxidative stress results in global genomic instability in cells, our current study examined the genomic alterations caused by H2O2 exposure at the whole genome level in yeast. Using SNP microarrays and genome sequencing, we mapped H2O2-induced genomic alterations in the yeast genome ranging from point mutations and mitotic recombination to chromosomal aneuploidy. Our results suggested most H2O2-induced mitotic recombination events were the result of DNA double-stand breaks generated by hydroxyl radicals. Moreover, the mutagenic effect of H2O2 was shown to be largely dependent on DNA polymerase ζ. Lastly, we showed that H2O2 exposure allows rapid phenotypic evolution in yeast strains. Our findings indicate DNA lesions resulting from H2O2 may be general factors that drive genome instability and phenotypic evolution in organisms.
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Periodontitis: Genomic instability implications and associated risk factors.
Borba, TT, Molz, P, Schlickmann, DS, Santos, C, Oliveira, CF, Prá, D, Neto, LK, Franke, SIR
Mutation research. Genetic toxicology and environmental mutagenesis. 2019;:20-23
Abstract
Periodontitis is a bacterial infection characterized by the presence of a dense inflammatory infiltrate, which may result in increased DNA damage and other nuclear/cellular abnormalities. Therefore, it is important to evaluate the periodontal diseases influence on DNA damage and other nuclear/cellular abnomalies formation as cancer risk markers. Thus, the aim of this study was to evaluate the periodontal diseases effect, according to its severity, on the occurrence of DNA damage and other nuclear/cellular abnormalities. This is a cross-sectional study with 77 subjects from the dentistry clinic of the University of Santa Cruz do Sul, Brazil, divided in control group (26 subjects), moderate periodontal disease group (26 subjects) and severe periodontal disease group (25 subjects). All subjects answered self-referenced questionnaires, underwent periodontal clinical examinations and allowed the collection of oral mucosa cells for the BMCyt. In relation to DNA damage biomarkers (micronuclei (MN) and/or nuclear buds (NBUD)), our results indicated no increase in MN frequencies (p > 0.05), however it indicated significant difference in NBUD frequencies between groups (p < 0.024). This result suggests that the periodontal disease status may influence DNA damage. Regarding the other nuclear/cellular abnormalities, was observed a significant difference in the binucleated (BN) frequencies between groups (p < 0.05). Moreover, the periodontitis severity was associated to an increase in the combined (summed) frequency of cells with different levels of DNA damage (MN and/or NBUD), cytokinetic defects (BN cells) and/or cell death (karyorrhexis, pyknotic and karyolytic cells) (r = 0.235; p = 0.040). Periodontal disease depending on its severity, induces nuclear anomalies in buccal cells.
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Effects of crocin in reducing DNA damage, inflammation, and oxidative stress in multiple sclerosis patients: A double-blind, randomized, and placebo-controlled trial.
Ghiasian, M, Khamisabadi, F, Kheiripour, N, Karami, M, Haddadi, R, Ghaleiha, A, Taghvaei, B, Oliaie, SS, Salehi, M, Samadi, P, et al
Journal of biochemical and molecular toxicology. 2019;(12):e22410
Abstract
Multiple sclerosis (MS) is an autoimmune disease in which the immune system attacks the nerve cells, resulting in neurological disorders. Oxidative stress, free radicals, and neuritis have important roles in MS pathogenesis. Here, we aim to evaluate the effect of crocin on inflammatory markers, oxidative damage, and deoxyribonucleic acid (DNA) damage in the blood of patients with MS. A total of 40 patients were divided into two groups, drug and placebo-treated groups, using random assignment. Participants of the intervention and control groups received two crocin capsules or placebo per day for 28 days, respectively. Findings revealed a significant decrease in the level of important pathogenic factors in MS, including lipid peroxidation, DNA damage, tumor necrosis factor-alpha, and interleukin 17 as well as a significant increase in the total antioxidant capacity in the serum of patients treated with crocin compared with the placebo group. Our results suggest the beneficial and therapeutic effects of crocin in MS.
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Sub-optimal Application of a High SPF Sunscreen Prevents Epidermal DNA Damage in Vivo.
Young, AR, Greenaway, J, Harrison, GI, Lawrence, KP, Sarkany, R, Douki, T, Boyer, F, Josse, G, Questel, E, Monteil, C, et al
Acta dermato-venereologica. 2018;(9):880-887
Abstract
The cyclobutane pyrimidine dimer (CPD) is a potentially mutagenic DNA photolesion that is the basis of most skin cancers. There are no data on DNA protection by sunscreens under typical conditions of use. The study aim was to determine such protection, in phototypes I/II, with representative sunscreen-user application. A very high SPF formulation was applied at 0.75, 1.3 and 2.0 mg/cm2. Unprotected control skin was exposed to 4 standard erythema doses (SED) of solar simulated UVR, and sunscreen-treated sites to 30 SED. Holiday behaviour was also simulated by UVR exposure for 5 consecutive days. Control skin received 1 SED daily, and sunscreen-treated sites received 15 (all 3 application thicknesses) or 30 (2.0 mg/cm2) SED daily. CPD were assessed by quantitative HPLC-tandem mass spectrometry (HPLC-MS/MS) and semi-quantitative immunostaining. In comparison with unprotected control sites, sunscreen significantly (p ≤ 0.001-0.05) reduced DNA damage at 1.3 and 2.0 mg/cm2 in all cases. However, reduction with typical sunscreen use (0.75 mg/cm2) was non-significant, with the exception of HPLC-MS/MS data for the 5-day study (p <0.001). Overall, these results support sunscreen use as a strategy to reduce skin cancer, and demonstrate that public health messages must stress better sunscreen application to get maximal benefit.
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Sensitization of prostate cancer to radiation therapy: Molecules and pathways to target.
Yao, M, Rogers, L, Suchowerska, N, Choe, D, Al-Dabbas, MA, Narula, RS, Lyons, JG, Sved, P, Li, Z, Dong, Q
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2018;(2):283-300
Abstract
Radiation therapy is used to treat cancer by radiation-induced DNA damage. Despite the best efforts to eliminate cancer, some cancer cells survive irradiation, resulting in cancer progression or recurrence. Alteration in DNA damage repair pathways is common in cancers, resulting in modulation of their response to radiation. This article focuses on the recent findings about molecules and pathways that potentially can be targeted to sensitize prostate cancer cells to ionizing radiation, thereby achieving an improved therapeutic outcome.
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Impact of a (poly)phenol-rich extract from the brown algae Ascophyllum nodosum on DNA damage and antioxidant activity in an overweight or obese population: a randomized controlled trial.
Baldrick, FR, McFadden, K, Ibars, M, Sung, C, Moffatt, T, Megarry, K, Thomas, K, Mitchell, P, Wallace, JMW, Pourshahidi, LK, et al
The American journal of clinical nutrition. 2018;(4):688-700
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Abstract
BACKGROUND Epidemiologic evidence suggests that a diet rich in (poly)phenols has beneficial effects on many chronic diseases. Brown seaweed is a rich source of (poly)phenols. OBJECTIVE The aim of this study was to investigate the bioavailability and effect of a brown seaweed (Ascophyllum nodosum) (poly)phenol extract on DNA damage, oxidative stress, and inflammation in vivo. DESIGN A randomized, double-blind, placebo-controlled crossover trial was conducted in 80 participants aged 30-65 y with a body mass index (in kg/m2) ≥25. The participants consumed either a 400-mg capsule containing 100 mg seaweed (poly)phenol and 300 mg maltodextrin or a 400-mg maltodextrin placebo control capsule daily for an 8-wk period. Bioactivity was assessed with a panel of blood-based markers including lymphocyte DNA damage, plasma oxidant capacity, C-reactive protein (CRP), and inflammatory cytokines. To explore the bioavailability of seaweed phenolics, an untargeted metabolomics analysis of urine and plasma samples after seaweed consumption was determined by ultra-high-performance liquid chromatography-high-resolution mass spectrometry. RESULTS Consumption of the seaweed (poly)phenols resulted in a modest decrease in DNA damage but only in a subset of the total population who were obese. There were no significant changes in CRP, antioxidant status, or inflammatory cytokines. We identified phlorotannin metabolites that are considered potential biomarkers of seaweed consumption including pyrogallol/phloroglucinol-sulfate, hydroxytrifurahol A-glucuronide, dioxinodehydroeckol-glucuronide, diphlorethol sulfates, C-O-C dimer of phloroglucinol sulfate, and C-O-C dimer of phloroglucinol. CONCLUSIONS To the best of our knowledge, this work represents the first comprehensive study investigating the bioactivity and bioavailability of seaweed (poly)phenolics in human participants. We identified several potential biomarkers of seaweed consumption. Intriguingly, the modest improvements in DNA damage were observed only in the obese subset of the total population. The subgroup analysis should be considered exploratory because it was not preplanned; therefore, it was not powered adequately. Elucidation of the biology underpinning this observation will require participant stratification according to weight in future studies. This trial was registered at clinicaltrials.gov as NCT02295878.
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Translation acrobatics: how cancer cells exploit alternate modes of translational initiation.
Sriram, A, Bohlen, J, Teleman, AA
EMBO reports. 2018;(10)
Abstract
Recent work has brought to light many different mechanisms of translation initiation that function in cells in parallel to canonical cap-dependent initiation. This has important implications for cancer. Canonical cap-dependent translation initiation is inhibited by many stresses such as hypoxia, nutrient limitation, proteotoxic stress, or genotoxic stress. Since cancer cells are often exposed to these stresses, they rely on alternate modes of translation initiation for protein synthesis and cell growth. Cancer mutations are now being identified in components of the translation machinery and in cis-regulatory elements of mRNAs, which both control translation of cancer-relevant genes. In this review, we provide an overview on the various modes of non-canonical translation initiation, such as leaky scanning, translation re-initiation, ribosome shunting, IRES-dependent translation, and m6A-dependent translation, and then discuss the influence of stress on these different modes of translation. Finally, we present examples of how these modes of translation are dysregulated in cancer cells, allowing them to grow, to proliferate, and to survive, thereby highlighting the importance of translational control in cancer.