The role of mitochondrial DNA damage in the citotoxicity of reactive oxygen species

Mitochondria contain their own genome, a small circular molecule of around 16.5 kbases. The mitochondrial DNA (mtDNA) encodes for only 13 polypeptides, but its integrity is essential for mitochondrial function, as all 13 proteins are regulatory subunits of the oxidative phosphorylation complexes. Nonetheless, the mtDNA is physically associated with the inner mitochondrial membrane, where the majority of the cellular reactive oxygen species are generated. In fact, the mitochondrial DNA accumulates high levels of oxidized lesions, which have been associated with several pathological and degenerative processes. The cellular responses to nuclear DNA damage have been extensively studied, but so far little is known about the functional outcome and cellular responses to mtDNA damage. In this review we will discuss the mechanisms that lead to damage accumulation and the in vitro models we are establishing to dissect the cellular responses to oxidative damage in the mtDNA and to sort out the differential cellular consequences of accumulation of damage in each cellular genome, the nuclear and the mitochondrial genome.

Citotoxicity and immune response induced by organopalladium(II) compounds in mice bearing Ehrlich ascites tumour

Cyclometallated palladium(II) complexes are reactive inorganic compounds employed in several biological studies because of their antitumour potential and interaction with immune system. In the present study, the immune and citotoxic response induced by two organopalladated complexes: [{Pd(N,C-dmba)} 2(μ-NCS) 2] (1), [Pd(C-dmba)(NCS)(dppp)] (2) [dmba = N,N′-dimethylbenzylamine, dppp = 1,3-bis(diphenylphosphino)propane] and cisplatin (cis-DDP), as standard, were investigated in mice bearing Ehrlich ascites tumour. The mice were divided into five groups and inoculated with the compounds (1) or (2) or cisplatin, or only vehicle or phosphate-buffered saline (PBS). Many parameters were evaluated, such as tumour cell percentage in the peritoneal exsudate, levels of seric nitric oxide (NO) and tumour necrosis factor-alpha (TNF-α) and increase in life span. Analysis of all data revealed, for compound (2), an activity similar to that presented by cisplatin, resulting in increased life span, lower levels of seric TNF-α and increase in NO production. ©2007 Sociedade Brasileira de Química.

Citotoxicidade e genotoxicidade do Listerine em culturas de Escherichia coli e plamídios

A utilização de testes de biocompatibilidade de materiais odontológicos é necessária para avaliar a segurança dos mesmos. Listerine é um enxaguatório comercial usado para a prevenção e tratamento da gengivite. O objetivo do estudo foi avaliar os efeitos citotóxico e genotóxico do Listerine em culturas de Escherichia coli e plasmídios. Na avaliação da citotoxicidade, culturas de E. coli AB1157 e BW9091 foram incubadas com Listerine (10, 50 e 100%) e o crescimento acompanhado pela densidade óptica (DO) em 600nm por 7 horas(h). Para avaliar a sobrevivência, culturas de E. coli AB1157, em fase exponencial, foram centrifugadas, ressuspensas em solução salina (NaCl 0,9%) e incubadas (1h, 37C) com Listerine (10, 50, 100%, 1h, 37 C). Alíquotas foram semeadas em placas de Petri contendo meio nutritivo nos tempos 0, 30 e 60 minutos e armazenadas em estufa bacteriológica (18h, 37 C). As unidades formadoras de colônias contadas e as frações de sobrevivência (FS) calculadas. Como controles, culturas tratadas salina ou etanol (21,6%). Para genotoxicidade, plasmídios pBSK foram incubados com Listerine (10, 50 e 100%) e com etanol (2,16%, 10,8% e 21,6%), associados ou não ao SnCl2(200g/mL, 30 minutos, temperatura ambiente), realizada eletroforese em gel de agarose (0,8%, 8V/cm), observados por transiluminação UV e obtido o percentual da forma superespiralada (%SE). Os resultados indicam que o enxaguatório Listerine foi capaz de inibir o crescimento bacteriano de culturas de E. coli na maior concentração utilizada. O enxaguatório, na maior concentração, diminuiu a sobrevivência das culturas bacterianas testadas. Listerine não modificou o perfil eletroforético do plasmídios, indicando ausência de efeito genotóxico e também foi capaz de proteger os plamídios da ação do SnCl2. Além disso, o etanol, na mesma concentração presente no Listerine, não alterou o perfil eletroforético dos plasmídios, sendo capaz de protegê-lo da ação do SnCl2. Os resultados indicaram que o Listerine apresentou efeito citotóxico em culturas de E. coli e ausência de potencial genotóxico em plamídios, sendo capaz de protegê-los, bem como o etanol, dos efeitos genotóxicos do SnCl2.

Chemical composition and pharmacological activities of essential oils of Lavandula spp.

Lavandula spp. belong to the family Lamiatae and some species are often used in popular medicine and have been used for centuries in a large number of medical applications and in aromatherapy. Although similar ethnobotanical properties of Lavandula spp., its essential oils, general chemical composition and therapeutic applications differ from different species. Lavandula stoechas L. subsps. luisieri (Rozeira) Rozeira and L. viridis L’Hér are endemic to the Iberian Peninsula, widespread in the South of Portugal, namely in Southern Alentejo and Algarve. The aim of our study was evaluate the chemical composition and toxicological and pharmacological activities of leaves essential oils of spontaneous plants of L. stoechas L. subsps. luisieri (Alentejo) and L. viridis (Algarve). The essential oils of these wild plants, collected in spring, were obtained by hydrodistillation in a Clevenger-type apparatus and its chemical composition was evaluated by GC/FID. The acute toxicity of essential oils was evaluated "in vitro" using brine shrimp (LC50) and "in vivo" using Swiss mice (DL50). The analgesic and anti-inflammatory pharmacological properties of L. stoechas subsp. luisieri essential oil were evaluated in mouse or rats by the Amour-Smith and carrageen-induced paw edema tests, respectively. Results showed important differences in chemical composition of essential oils from two species analyzed either to diversity and proportion of its constituents. The essentials oils showed citotoxicity against Artemia salina and a DL50 higher than 2000 mg/kg for mice. The analgesic and anti-inflammatory activities of essential oils were exhibit for the doses of 100 and 200 mg/kg.

Efeitos da ingestão de simbiótico e indol-3-carbinol sobre o processo de carcinogênese química de cólon em ratos Wistar alimentados com dieta contendo heme

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inmunoterapia en pacientes con cáncer de pulmón de células no pequeñas versus terapia convencional. Revisión sistemática

RESUMEN Antecedentes y Justificación: El cáncer de pulmón es la principal causa de muerte relacionada con Cáncer en el mundo. El cáncer pulmonar de células no pequeñas (Non-Small-cell lung cancer NSCLC) representa el 85% de todos los cánceres de pulmón y en un 40% es diagnosticado tardíamente y con los tratamientos disponibles actualmente (cirugía, radioterapia y quimioterapia) presenta una supervivencia a 5 años entre el 10 y el 15%. En los últimos años han surgido nuevos tratamientos basados en la inmunoterapia que prometen mejorar la supervivencia de estos pacientes. Objetivo: Determinar la eficacia de la inmunoterapia en el tratamiento del cáncer de pulmón de células no pequeñas (NSCLC) con el fin de integrar la información disponible para su posterior uso en la clínica. Metodología: Se realizó búsqueda exhaustiva de la literatura disponible del 1 de Enero de 2003 al 31 de Diciembre de 2013. Se examinaron las siguientes bases de datos: Pubmed, Scielo, Medline, Lilacs, EMBASE, Bandolier, peDRO y Cochrane. Se utilizaron los términos MeSH de búsqueda: immunotherapy, NSCLC, clinical trials. Resultados: de 163 referencias identificadas en las bases de datos, 12 fueron seleccionadas para la revisión. Se identificaron 11 estrategias inmunoterapéuticas que fueron complementarias al uso de quimioterapia, radioterapia o ambas. No se encontró diferencia significativa entre la supervivencia global de los grupos de intervención y controles con excepción de 1 artículo. La mayoría de efectos secundarios fueron de leves a moderados y no hubo diferencias significativas entre los grupos. Discusión: no se evidenció un aumento significativo de la supervivencia global con la utilización de inmunoterapias, a excepción de la que emplea células asesinas inducidas por citocinas junto a células dendríticas. Sin embargo es necesario esperar resultados de estudios fase III en curso.

A human ribonuclease induces apoptosis associated with p21WAF1/CIP1 induction and JNK inactivation

Ribonucleases are promising agents for use in anticancer therapy. Among the different ribonucleases described to be cytotoxic, a paradigmatic example is onconase which manifests cytotoxic and cytostatic effects, presents synergism with several kinds of anticancer drugs and is currently in phase II/III of its clinical trial as an anticancer drug against different types of cancer. The mechanism of cytotoxicity of PE5, a variant of human pancreatic ribonuclease carrying a nuclear localization signal, has been investigated and compared to that of onconase. Methods: Cytotoxicity was measured by the MTT method and by the tripan blue exclusion assay. Apoptosis was assessed by flow cytometry, caspase enzymatic detection and confocal microscopy. Cell cycle phase analysis was performed by flow cytometry. The expression of different proteins was analyzed by western blot.n Results: We show that the cytotoxicity of PE5 is produced through apoptosis, that it does not require the proapoptotic activity of p53 and is not prevented by the multiple drug resistance phenotype. We also show that PE5 and onconase induce cell death at the same extent although the latter is also able to arrest the cell growth. We have compared the cytotoxic effects of both ribonucleases in the NCI/ADR-RES cell line by measuring their effects on the cell cycle, on the activation of different caspases and on the expression of different apoptosis- and cell cycle-related proteins. PE5 increases the number of cells in S and G2/M cell cycle phases, which is accompanied by the increased expression of cyclin E and p21WAF1/CIP1 together with the underphosphorylation of p46 forms of JNK. Citotoxicity of onconase in this cell line does not alter the cell cycle phase distribution and it is accompanied by a decreased expression of XIAP. Conclusions: We conclude that PE5 kills the cells through apoptosis associated with the p21WAF1/CIP1 induction and the inactivation of JNK. This mechanism is significantly different from that found for onconase

Avaliação do potencial genotóxico e citotóxico associado a queima artesanal da castanha de caju no Município de João Câmara

The Brazil is the third largest producer of cashew nuts in the world. Despite the social and economic importance of the cashew nut, its production is still carried out artisanally. One of the main problems encountered in the cashew production chain are the conditions under which the roasting of the nut occurs to obtain the kernel from the shell. In the present study was conducted a biomonitoring of the genotoxic and cytotoxicity effects associated with the elements from the cashew nut roasting in João Câmara - RN, semi-arid region of Brazil. To assess the genotoxic was used the bioassay of micronucleus (MN) in Tradescantia pallida. In addition, it was performed a comparative between the Tradescantia pallida and KU-20 and other biomarkers of DNA damage, such as the nucleoplasmic bridges (NBP) and nuclear fragments (NF) were quantified. The levels of particulate matter (PM1.0, PM2.5, PM10) and black carbon (BC) were also measured and the inorganic chemical composition of the PM2.5 collected was determined using X-ray fluorescence spectrometry analysis and the assessment of the cytotoxicity by MTT assay and exclusion method by trypan blue. . For this purpose, were chosen: the Amarelão community where the roasting occurs and the Santa Luzia farm an area without influence of this process. The mean value of PM2.5 (Jan 2124.2 μg/m3; May 1022.2 μg/m3; Sep 1291.9 μg/m3) and BC (Jan 363.6 μg/m3; May 70.0 μg/m3; Sep 69.4 μg/m3) as well as the concentration of the elements Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br and Pb obtained at Amarelão was significantly higher than at Santa Luzia farm. The genotoxicity tests with T. pallida indicated a significant increase in the number of MN, NBP and NF and it was found a negative correlation between the frequency of these biomarkers and the rainfall. The concentrations of 200 μg/mL and 400 μg/mL of PM2.5 were cytotoxic to MRC-5 cells. All together, the results indicated genotoxicity and citotoxicity for the community of Amarelão, and the high rates of PM2.5 considered a potential contributor to this effect, mainly by the high presence of transition metals, especially Fe, Ni, Cu, Cr and Zn, these elements have the potential to cause DNA damage. Other nuclear alterations, such as the NPBs and NFs may be used as effective biomarkers of DNA damage in tetrads of Tradescantia pallida. The results of this study enabled the identification of a serious occupational problem. Accordingly, preventative measures and better practices should be adopted to improve both the activity and the quality of life of the population. These measures are of fundamental importance for the sustainable development of this activity.

Estudo do efeito dos metabólitos do benzeno e tolueno sobre as mitocôndris cerebrais e hepáticas de ratos

Aim: The aim of this work was to investigate the hypothesis that catechol and 3MC inhibit FADH2-linked basal respiration in mitochondria isolated from rat liver and brain homogenates. Moreover, catechol ability to induce DNA damage in rat brain cells through the comet assay (alkaline single-cell gel electrophoresis assay) was also observed. Methods: Two different catechols were evaluated: pirocatechol (derived from benzene) and 3-methylcatechol (derived from toluene); rat liver and brain homogenates were incubated with 1mM catechol at pH 7.4 for up to 30 minutes. After that, mitochondrial fractions were isolated by differential centrifugation. Basal oxygen uptake was measured using a Clark-type electrode after the addition of 10 mM sodium succinate for a period of 12 minutes. In additional experiments, rat brain cells were treated with 1, 5 and 10mM pirocatechol for up to 20 minutes at 37º C, and submitted to electrophoresis. Results: Catechols (pirocatechol and 3methylcatechol) induced a time-dependent partial inhibition of FADH2-linked basal mitochondrial respiration. Indeed, pirocatechol was able to produce a dosedependent DNA oxidative damage in rat brain cells by 2 and 4 injury levels. These results suggest that reactive oxygen species generated by the oxidation of catechols, induced an impairment on mitochondrial respiration and a DNA damage, which might be related to their citotoxicity. Conclusion: Catechols produced an inhibition of basal respiration associated to FADH2 in isolated liver and brain mitochondria; 3-methylcatechol, at the same concentration, produced similar toxicity in the mitochondrial model. Indeed, pirocatechol induced a DNA damage in rat brain cells, mainly observed in comets formation and consequent DNA degradation

Allium cepa test in environmental monitoring: A review on its application

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Brine shrimp (Artemia salina Leach) bioassay of extracts from Lychnophoriopsis candelabrum and different Lychnophora species

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Liquid crystalline formulations containing modified surface TiO2 nanoparticles obtained by sol-gel process

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Correlation among Antioxidant, Antimicrobial, Hemolytic, and Antiproliferative Properties of Leiothrix spiralis Leaves Extract

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Citotoxicidade de Styrax camporum Pohl em macrófagos peritoneais e a liberação de H2O2

The immunological response includes wide contexts involving several cells, and the macrophage is crucial in the cellular immune response. Several stimuli to macrophage membrane may induce the liberation of H2O2, contributing to antibacterial and cytotoxicical actions. Nowadays, there is a tendency to study natural products to verify their capacity of acting in the immune system. This study evaluated the citotoxicity of the bulk extract and the hexanic and acetic fractions extracted from Styrax camporum Pohl (Styracaceae) and the production of H2O2, on murine peritonal macrophages cultures exposed to fractions extracted from this plant. The results showed that the fraction HX 2 mg/ml produced the liberation of H 2O2 in high concentrations and to 4 mg/ml was observed high citotoxicity. The fractions AC did not produce the liberation of H 2O2 and EB was produced in low levels. We conclude that this HX is a potent stimulator of macrophage.