Showing papers by "Lusânia Maria Greggi Antunes published in 2020"

Caffeic acid and chlorogenic acid cytotoxicity, genotoxicity and impact on global DNA methylation in human leukemic cell lines

Abstract: Dietary phenolic compounds such as caffeic and chlorogenic acid exert an antiproliferative effect and modulate the gene-specific DNA methylation status in human breast tumor cells, but it remains unclear whether they interfere with global DNA methylation in human leukemia cells. We examined whether caffeic and chlorogenic acid (1-250 µM) exert antitumor action in human promyelocytic leukemia cells (HL-60) and human acute T-cell leukemia cells (Jurkat). Caffeic and chlorogenic acid did not reduce cell viability in the two cell lines, as assessed using the neutral red uptake and MTT assays. These phenolic acids (1-100 μM) neither induced DNA damage (comet assay) nor increased the micronuclei frequency (micronucleus assay) in HL-60 and Jurkat cells, indicating that they were not genotoxic or mutagenic. Analysis of global DNA methylation levels using a 5-mC DNA ELISA kit revealed that chlorogenic acid at a non-cytotoxic concentration (100 μM) induced global DNA hypomethylation in Jurkat cells, but not in HL-60 cells, suggesting that it exerts a cell-specific effect. Caffeic acid did not change global DNA methylation. As other phenolic compounds, chlorogenic acid probably modulates DNA methylation by targeting DNA methyltransferases. The hypomethylating action of chlorogenic acid can be beneficial against hematological malignances whose pathogenic processes involve impairment of DNA methylation.

Gold-Coated Superparamagnetic Iron Oxide Nanoparticles Attenuate Collagen-Induced Arthritis after Magnetic Targeting.

Abstract: The aim of the study was to evaluate if gold-coated superparamagnetic iron oxide nanoparticles (AuSPION) magnetic-targeted to the arthritic articulation of collagen induced arthritis (CIA) rats are able to ameliorate rheumatoid arthritis without producing significant biological adverse effects in comparison to colloidal Au nanoparticles (AuC) and metotrexate (MTX). Male Wistar rats were divided into control; arthritic; AuSPION (150 μg kg−1); AuC (150 μg kg−1) and MTX (2.5 μg kg−1). Treatments were administered thrice every other day by the intraperitoneal route 15 min after all groups had a neodymium magnet coupled to the right ankle joint (kept for 1 h). Paw edema and body weight were measured weekly. Joint sections were evaluated by Haematoxylin & Eosin and immunohistochemistry (TNF-α, IL-1β). Biomarkers of oxidative stress were used to evaluate toxicity. Among the evaluated treatments, AuSPION led to significant clinical improvements (decreased edema and infiltration by leukocytes as well as less positively immunostained cells for both TNF-α and IL-1β in synovium) accompanied by a lack of toxicity as indicated by redox state and genotoxicity assays. Our results clearly indicate that the magnetic targeting of AuSPION suppresses joint edema and inflammation, cytokine expression as well as the redox imbalance, thereby contributing to an amelioration of arthritis severity in CIA rats. The results demonstrate for the first time the potentiality of AuSPION administration under a magnetic field as an attractive alternative for future treatments of rheumatic diseases.

Ruthenium (II) complex cis-[Ru II (ŋ 2 -O 2 CC 7 H 7 O 2 )(dppm) 2 ]PF 6 -hmxbato induces ROS-mediated apoptosis in lung tumor cells producing selective cytotoxicity

Abstract: Ruthenium complexes have been extensively explored as potential molecules for cancer treatment. Considering our previous findings on the remarkable cytotoxic activity exhibited by the ruthenium (II) complex 3-hydroxy-4-methoxybenzoate (hmxbato)-cis-[RuII(ŋ2-O2CC7H7O2)(dppm)2]PF6 against Leishmania promastigotes and also the similar metabolic characteristics between trypanosomatids and tumor cells, the present study aimed to analyze the anticancer potential of hmxbato against lung tumor cells, as well as the partial death mechanisms involved. Hmxbato demonstrated selective cytotoxicity against A549 lung tumor cells. In addition, this complex at a concentration of 3.8 µM was able to expressively increase the generation of reactive oxygen species (ROS) in tumor cells, causing an oxidative stress that may culminate in: (1) reduction in cellular proliferation; (2) changes in cell morphology and organization patterns of the actin cytoskeleton; (3) cell arrest in the G2/M phase of the cell cycle; (4) apoptosis; (5) changes in the mitochondrial membrane potential and (6) initial DNA damage. Furthermore, we demonstrated that the induction of programmed cell death can occur by the intrinsic apoptotic pathway through the activation of caspases. It is also worth highlighting that hmxbato exhibited predominant actions on A549 tumor cells in comparison to BEAS-2B normal bronchial epithelium cells, which makes this complex an interesting candidate for the design of new drugs against lung cancer.

Açai pulp supplementation as a nutritional strategy to prevent oxidative damage, improve oxidative status, and modulate blood lactate of male cyclists

Abstract: Acai pulp is a source of phytochemicals and has been associated with antioxidant, anti-inflammatory, and antigenotoxic effects. This study aimed to assess the effects of acai pulp consumption on oxidative, inflammatory, and aerobic capacity markers of cyclist athletes. A crossover, randomized, placebo-controlled, single-blind study was developed with ten male cyclists (33.5 ± 4.7 years old, body mass index of 23.9 ± 1.38 kg/m2, and training load around 1875 ± 238 AU/week). The athletes consumed 400 g/day of pasteurized acai pulp (AP) or placebo (PL) for 15 days, with a 30-day wash-out period between trials. Lipid peroxidation, serum antioxidant capacity, DNA damage in peripheral blood (Comet assay), IL-6 and TNF-alpha, blood lactate concentration during effort, anaerobic threshold intensity (ATi), maximum workload reached (Wmax), rating of perceived exertion threshold (RPET), and heart rate threshold (HRT) were evaluated before and after each intervention. Data were analyzed using a linear regression model with mixed effects (p ≤ 0.05). Increased serum antioxidant capacity (p = 0.006) and decreased lipid peroxidation (p = 0.01) were observed in subjects after intervention with AP. Blood lactate levels during effort significantly decreased (by 29%, p = 0.025) and ATi increased (p = 0.006) after AP. No significant effect on DNA damage was attributed to AP consumption. We found notable effects of AP intervention on antioxidant status in athletes. Both the reduction in blood lactate concentration and increase in ATi during the effort suggest an overall improvement in the aerobic capacity of the cyclists, confirming that AP consumption may influence variables associated with performance in endurance athletes.

Bothrops moojeni L-amino acid oxidase induces apoptosis and epigenetic modulation on Bcr-Abl+ cells.

Abstract: Background: Resistance to apoptosis in chronic myeloid leukemia (CML) is associated with constitutive tyrosine kinase activity of the Bcr-Abl oncoprotein. The deregulated expression of apoptosis-related genes and alteration in epigenetic machinery may also contribute to apoptosis resistance in CML. Tyrosine kinase inhibitors target the Bcr-Abl oncoprotein and are used in CML treatment. The resistance of CML patients to tyrosine kinase inhibitors has guided the search for new compounds that may induce apoptosis in Bcr-Abl+ leukemic cells and improve the disease treatment. Methods: In the present study, we investigated whether the L-amino acid oxidase isolated from Bothrops moojeni snake venom (BmooLAAO-I) (i) was cytotoxic to Bcr-Abl+ cell lines (HL-60.Bcr-Abl, K562-S, and K562-R), HL-60 (acute promyelocytic leukemia) cells, the non-tumor cell line HEK-293, and peripheral blood mononuclear cells (PBMC); and (ii) affected epigenetic mechanisms, including DNA methylation and microRNAs expression in vitro. Results: BmooLAAO-I induced ROS production, apoptosis, and differential DNA methylation pattern of regulatory apoptosis genes. The toxin upregulated expression of the pro-apoptotic genes BID and FADD and downregulated DFFA expression in leukemic cell lines, as well as increased miR-16 expression - whose major predicted target is the anti-apoptotic gene BCL2 - in Bcr-Abl+ cells. Conclusion: BmooLAAO-I exerts selective antitumor action mediated by H2O2 release and induces apoptosis, and alterations in epigenetic mechanisms. These results support future investigations on the effect of BmooLAAO-I on in vivo models to determine its potential in CML therapy.

A Synthetic Snake-Venom-Based Tripeptide Protects PC12 Cells from the Neurotoxicity of Acrolein by Improving Axonal Plasticity and Bioenergetics

Abstract: The synthetic peptide p-BTX-I is based on the native peptide (formed by glutamic acid, valine and tryptophan) isolated from Bothrops atrox venom. We have previously demonstrated its neuroprotective and neurotrophic properties in PC12 cells treated with the dopaminergic neurotoxin 1-methyl-4-phenylpyridinium (MPP+). Now, we have investigated the neuroprotective effects and mechanisms of p-BTX-I against the toxicity of acrolein in PC12 cells. Studies have demonstrated that acrolein might play an important role in the etiology of Alzheimer's disease (AD), which is characterized by neuronal and synaptic loss. Our results showed that not only acrolein reduced cell differentiation and cell viability, but also altered the expression of markers of synaptic communication (synapsin I), energy metabolism (AMPK-α, Sirt I and glucose uptake), and cytoskeleton (β-III-tubulin). Treatment with p-BTX-I increased the percentage of differentiation in cells treated with acrolein and significantly attenuated cell viability loss, besides counteracting the negative effects of acrolein on synapsin I, AMPK-α, Sirt I, glucose uptake, and β-III-tubulin. Additionally, p-BTX-I alone increased the expression of apolipoprotein E (apoE) gene, associated with the proteolytic degradation of β-amyloid peptide aggregates, a hallmark of AD. Taken together, these findings demonstrate that p-BTX-I protects against acrolein-induced neurotoxicity and might be a tool for the development of novel drugs for the treatment of neurodegenerative diseases.

DNA damage is inversely associated to blood levels of DHA and EPA fatty acids in Brazilian children and adolescents

Abstract: This study aimed to investigate the association between DNA damage and blood levels of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), retinol, beta-carotene and riboflavin in Brazilian children and adolescents. Subjects (n = 140) were healthy boys and girls aged 9 to 13 years in Ribeirao Preto (SP, Brazil). Data collection included anthropometry, assessment of energy intake and blood sampling. DNA damage was evaluated by single-cell gel electrophoresis (comet assay). Principal component analysis (PCA) was used to verify associations between blood concentrations of vitamins, polyunsaturated fatty acids and DNA damage. Multiple regression analyses, k-means cluster, and analysis of covariance (ANCOVA), adjusted for confounding variables such as age, sex, energy intake, body mass index and total cholesterol (when needed), were applied to confirm the associations. PCA explained 69.4% of the inverse relationships between DNA damage and blood levels of DHA, EPA, retinol, and beta-carotene. Results were confirmed by ANCOVA and multiple regression analyses for DHA and EPA. In conclusion, omega-3-fatty acids were inversely associated with DNA damage in Brazilian children and adolescents and may be a protective factor against the development of future diseases.

Effects of sulforaphane on the oxidative response, apoptosis, and the transcriptional profile of human stomach mucosa cells in vitro.

Abstract: Oxidative stress is a critical factor in the pathogenesis of several gastrointestinal diseases. Sulforaphane (SFN), a bioactive compound found in cruciferous vegetables, activates the redox-sensitive nuclear erythroid 2-related factor 2 (NRF2). In addition to its protective role, SFN exerts cytotoxic effects on cancer cells. However, there is a lack of information concerning the toxicity of SFN in normal cells. We investigated the effects of SFN on cell viability, antioxidant defenses, and gene expression in human stomach mucosa cells (MNP01). SFN reduced ROS formation and protected the cells against induced oxidative stress but high concentrations increased apoptosis. An intermediate SFN concentration (8 μM) was chosen for RNA sequencing studies. We observed upregulation of genes of the NRF2 (antioxidant) pathway, the DNA damage response, and apoptosis signaling; whereas SFN downregulated cell cycle and DNA repair pathway genes. SFN may be cytoprotective at low concentrations and cytotoxic at high concentrations.