Catequinas del té verde: efectos antigenotóxicos y genotóxicos. Revisión sistemática / Green tea catechins: antigenotoxic and genotoxic effects. Systematic review

Las catequinas del té verde (Camellia sinensis) (CTV) presentan efectos benéficos para la salud asociados a su potencial antioxidante. Por otra parte, el estrés oxidante es una de las vías de inducción de daño genotóxico. De ahí que, en la presente revisión se realizó un análisis de los efectos antigenotóxicos y genotóxicos de las CTV, haciendo énfasis en las vías implicadas en estos procesos y sus efectos en la salud. Se realizó una revisión de artículos indexados en las bases de datos de PubMed® y Science Direct® (2021) con las palabras clave "green tea" y "green tea catechins". Se delimitaron los estudios utilizando los operadores booleanos "AND", "OR" y "NOT" ("antigenotoxic", "genotoxic", "antioxidant" y "prooxidant"). En su mayoría se consideraron las publicaciones del 2016 al 2021. Se observó que los efectos benéficos en la salud de las CTV están relacionados con: a) su actividad antioxidante mediante la captura, inhibición y prevención de la formación de las especies reactivas de oxígeno; b) la regulación del sistema antioxidante endógeno; c) la activación de los mecanismos de reparación al contribuir en la eliminación del aducto 8-hidroxi-2'-desoxiguanosina; d) la inducción de apoptosis en células con daño al ADN; y e) la inhibición de la inflamación relacionada con su actividad antiapoptótica. Si bien, en algunos de los estudios se reportaron efectos genotóxicos, estos a su vez contribuyeron en la eliminación de células con daño genético, por lo que, no se puede considerar del todo a la actividad genotóxica de las CTV como perjudiciales para la salud(AU)

The green tea catechins (Camellia sinensis) (CTV) have beneficial effects for health associated with their antioxidant potential. Moreover, oxidative stress is one of the pathways for inducing genotoxic damage. Hence, in this review, an analysis of the antigenotoxic and genotoxic effects of CTV was carried out, emphasizing the pathways involved in these processes and their effects on health. A review of articles indexed in the PubMed® and ScienceDirect® (2021) databases with the keywords "green tea" and "green tea catechins" was carried out. Studies were delimited using the Boolean operators "AND", "OR" and "NOT" ("antigenotoxic", "genotoxic", "antioxidant" and "prooxidant"). For the most part, publications from 2016 to 2021 were considered. It was observed that the beneficial health effects of CTVs are related to: a) their antioxidant activity through the capture, inhibition and prevention of the formation of reactive oxygen species; b) the regulation of the endogenous antioxidant system; c) the activation of the repair mechanisms by contributing to the elimination of the 8-hydroxy-2'-deoxyguanosine adduct; d) the induction of apoptosis in cells with DNA damage; and e) the inhibition of inflammation related to its antiapoptotic activity. Although some of the studies reported genotoxic effects, these in turn contributed to the elimination of cells with genetic damage. Therefore, the genotoxic activity of CTV cannot be considered as harmful to health

Evaluation of the cytotoxic and genotoxic effects by melamine and cyanuric acid co-exposure in human embryonic kidney 293 cells

The melamine and cyanuric acid (CA) complex has been suggested to cause the toxic effects observed in melamine-contaminated food or milk. However, the cytotoxic and genotoxic effects of co-exposure to melamine and CA are not fully clear. Therefore, the cytotoxic effects of melamine and CA were first examined by co‐exposure in human kidney 293 cells using the MTT assay. During a 24-h period for the three concentrations tested (0.5, 1, and 5 mg/mL), neither melamine nor CA alone showed significant toxic effects on 293 cells at 0.5 mg/mL, while higher concentrations led to decreased in cell viability. However, co-exposure to several combinations of melamine and CA [100:1, 10:1, 1:10, and 1:100 (v:v), at a final concentration of 0.5 mg/mL] did cause cytotoxicity with higher levels of CA leading to higher cytotoxicity. By contrast, while neither melamine nor CA alone induced phosphorylated-H2AX (γH2AX) foci formation, melamine and CA at a 100:1 ratio induced γH2AX foci 24 h post-treatment. The alkaline comet assay also revealed the presence of DNA damage following melamine and CA co-exposure. In vivo assay also revealed the presence of melamine-CA complex in the kidney. These data indicated that the cytotoxic and genotoxic effects of melamine and CA co-exposure differ from those of melamine or CA alone.

Genotoxicity effects on Geophagus brasiliensis fish exposed to Doce River water after the environmental disaster in the city of Mariana, MG, Brazil / Efeitos da genotoxicidade em peixes da espécie Geophagus brasiliensis expostos a água do Rio Doce após o desastre ambiental na cidade de Marina, MG, Brasil

Abstract The Doce River basin has suffered the largest environmental accident ever occurred in Brazil with the influx of tailings from Fundão and Santarém, belonging to Samarco mining company, due to the disaster in Mariana. A spill between 50 and 60 million m3 of tailings was estimated by the company. According to Samarco, the wastewater was composed mainly of clay, silt and heavy metals like iron, copper and manganese. Thereby, the objective of the present study was evaluated the genotoxic damage in juvenile of Geophagus brasiliensis (Quoy e Gaimard, 1824) exposed to Doce river water before (DRWBA - Doce River water before acident) and after (DRWAA - Doce River water after acident) the influx of tailings from the Germano and Santarém Dam disasters in Mariana, MG, Brazil. For this, 24 individuals of the species G. brasiliensis (obtained on IFES/ALEGRE fish culture) were submitted to a bioassay with three treatments and eight replicates. The treatments were: 1) Control water (water from the urban water supply system, filtered with a 0.45 µm membrane), 2) DRBA and 3) DRAA. After 96 h, these fishes were anesthetized to remove blood for evaluation of genotoxic damage (micronucleus and comet). For the bioassay, a total of 80 L of The Doce River water were collected before the influx of tailings and after the influx and then submitted to metal quantification analysis. Fish exposed to DRWBA and DRWAA treatments showed a significant increase in both the number of erythrocyte micronuclei and the DNA damage index in relation to the control fish; however, they did not present any differences between the two treatments. The results demonstrate that the DRWBA treatment was already genotoxic for the fish, mainly due to dissolved Cu concentrations in the water. The DRWAA treatment probably presented genotoxicity due to the increase in the dissolved fraction and synergistic effects of several metals found in the tailings of the Mariana accident.

Resumo A bacia do Rio Doce sofreu o maior acidente ambiental com o influxo de rejeitos de Fundão e Santarém, pertencentes à empresa de mineração Samarco, devido ao desastre em Mariana. Um derramamento entre 50 e 60 milhões de m3 de rejeitos foi estimado pela empresa. De acordo com a Samarco, o rejeito despejado era composto principalmente de argila, silte e alguns metais pesados como ferro, cobre e manganês. Com isso, o presente estudo teve como objetivo avaliar os danos genotóxicos em juvenis de Geophagus brasilienses expostos a água do rio Doce antes (DRWAA - água do Rio Doce antes do acidente) e depois (DRWBA- água do Rio Doce depois do acidente) da chegada dos rejeitos do rompimento das barragens de Germano e Santarém em Mariana, MG, Brasil. Para isso, 24 indivíduos da espécie G. brasilienses (obtidos na piscicultura do IFES/ALEGRE) foram submetidos a um bioensaio com três tratamentos e oito réplicas. Os tratamentos eram: 1) Controle (com água do abastecimento urbano, filtrada com filtro analítico de 0,45 µm); 2) DRWBA e 3) DRWAA. Após um período de 96 h, esses peixes foram anestesiados para retirada de sangue para avaliação dos danos genotóxicos (micronúcleo e cometa). Para a realização do bioensaio, um total de 80 L de água do Rio Doce foram coletados antes da chegada dos rejeitos e outros 80 L foram coletados depois da chegada dos rejeitos e ambas foram submetidas a análises de quantificação de metal. Os peixes expostos ao DRWBA e ao DRWAA apresentaram um aumento significativo na quantidade de micronúcleos eritrocitários e no índice de danos do DNA em relação aos peixes controle, no entanto não apresentaram diferenças entre si. Os resultados obtidos demonstram que a DRWBA já era genotóxica para os peixes, principalmente, em função das concentrações de Cu dissolvido na água. A DRWAA apresentou genotixicidade, provavelmente, em função do aumento da fração dissolvida e do efeito sinérgico de diversos metais presentes nos rejeitos do acidente de Mariana.

Efeitos citotóxicos da duloxetina nas linhagens celulares MKN45 e NIH3T3 e efeitos genotóxicos em linfócitos sanguíneos periféricos humanos / Cytotoxic effects of duloxetine on mkn45 and nih3t3 cell lines and genotoxic effects on human peripheral blood lymphocytes

ABSTRACT BACKGROUND: Gastric cancer is the second leading cause of cancer-related death globally. Unfortunately, the survival rate of the gastric cancer patients who underwent chemotherapy following surgery has been less than a half. Besides, chemotherapy has many side effects. Current evidence suggests that some antidepressants like duloxetine have growth-inhibiting effects against a number of cancer cell lines. OBJECTIVE: Thus, the aim of this study was to determine the cytotoxic and genotoxic effects of duloxetine on gastric cancer. METHODS: In this regard, the cytotoxicity and genotoxicity of duloxetine were investigated in MKN45 and NIH3T3 cell lines by MTT assay and on peripheral blood lymphocytes by MN assay. For this purpose, cells were cultured in 96 wells plate. Stock solutions of duloxetine and cisplatin were prepared. After cell incubation with different concentrations of duloxetine (1, 10, 25, 50, 100 and 200 μL), MTT solution was added. For micronucleus assay fresh blood was added to RPMI culture medium 1640 supplemented, and different concentrations of duloxetine (1, 10, 25, 50, 100 and 200 μL) were added. RESULTS: The cytotoxicity of duloxetine on MKN45 cancer cell line and NIH3T3 normal cell line were studied followed by MTT assay. duloxetine exhibited higher IC50 in the MKN45 cells in comparison with the NIH3T3 cells. In addition, genotoxic effect of duloxetine was evaluated by micronucleus assay. The results revealed that duloxetine induced more DNA damage at 100 and 200 μM and no significant difference at 200 μM with respect to cisplatin, but it had less genotoxic effects at 100 and 50 μM concentrations. CONCLUSION: Although, in this study, duloxetine had less genotoxicity than cisplatin in concentrations under 200 μM and showed cytotoxic effects as well, due to its IC50, it cannot be considered as a better choice for gastric cancer therapies with respect to cisplatin as a common anticancer drug.

RESUMO CONTEXTO: O câncer gástrico é a segunda principal causa de morte relacionada ao câncer globalmente. Infelizmente, a taxa de sobrevivência dos pacientes com câncer gástrico que se submeteram à quimioterapia após a cirurgia, tem sido inferior à metade. Além disso, a quimioterapia tem muitos efeitos colaterais. Evidências atuais sugerem que alguns antidepressivos como a duloxetina têm efeitos inibidores de crescimento contra um número de linhas de células cancerosas. OBJETIVO: Assim, o objetivo deste estudo foi determinar os efeitos citotóxicos e genotóxicos da duloxetina sobre o câncer gástrico. MÉTODOS: A este respeito, a citotoxicidade e a genotoxicidade da duloxetina foram investigadas em linhas celulares MKN45 e NIH3T3 por ensaio de MTT e por ensaio de MN em linfócitos periféricos de sangue. Para este efeito, as células foram cultivadas em 96 placas. Soluções de estoque de duloxetina e cisplatina foram preparadas. Após incubação celular com diferentes concentrações de duloxetina (1, 10, 25, 50, 100 e 200 μL), a solução de MTT foi adicionada. Para o teste do micronúcleo o sangue fresco foi adicionado ao meio de cultura RPMI 1640 suplementado, e as concentrações diferentes de duloxetina (1, 10, 25, 50, 100 e 200 μL) foram adicionadas. RESULTADOS: A citotoxicidade da duloxetina na linha celular cancerosa MKN45 e NIH3T3 linha celular normal foram estudadas e seguidas pelo ensaio de MTT. A duloxetina exibiu maior IC50 nas células MKN45 em comparação com as células NIH3T3. Além disso, o efeito genotóxico da duloxetina foi avaliado pelo ensaio de micronúcleos. Os resultados revelaram que a duloxetina induziu mais dano de DNA em 100 e 200 μM e não houve diferença significativa em 200 μM em relação à cisplatina, mas teve menos efeitos genotóxicos nas concentrações de 100 e 50 μM. CONCLUSÃO: Embora, neste estudo, a duloxetina tenha menos genotoxicidade do que a cisplatina em concentrações inferiores a 200 μm e também tenha mostrado efeitos citotóxicos, devido ao seu IC50, não pode ser considerada como uma escolha terapêutica melhor para o câncer gástrico no que diz respeito à cisplatina como uma droga anticâncer comum.

Evaluation of hydroxyurea genotoxicity in patients with sickle cell disease / Avaliação da indução de genotoxicidade pela hidroxiureia em pacientes com doença falciforme

ABSTRACT Objective To evaluate the induction of DNA damage in peripheral blood mononuclear cells of patients with sickle cell disease, SS and SC genotypes, treated with hydroxyurea. Methods The study subjects were divided into two groups: one group of 22 patients with sickle cell disease, SS and SC genotypes, treated with hydroxyurea, and a Control Group composed of 24 patients with sickle cell disease who were not treated with hydroxyurea. Peripheral blood samples were submitted to peripheral blood mononuclear cell isolation to assess genotoxicity by the cytokinesis-block micronucleus cytome assay, in which DNA damage biomarkers - micronuclei, nucleoplasmic bridges and nuclear buds - were counted. Results Patients with sickle cell disease treated with hydroxyurea had a mean age of 25.4 years, whereas patients with sickle cell disease not treated with hydroxyurea had a mean age of 17.6 years. The mean dose of hydroxyurea used by the patients was 12.8mg/kg/day, for a mean period of 44 months. The mean micronucleus frequency per 1,000 cells of 8.591±1.568 was observed in the Hydroxyurea Group and 10.040±1.003 in the Control Group. The mean frequency of nucleoplasmic bridges per 1,000 cells and nuclear buds per 1,000 cells for the hydroxyurea and Control Groups were 0.4545±0.1707 versus 0.5833±0.2078, and 0.8182±0.2430 versus 0.9583±0.1853, respectively. There was no statistically significant difference between groups. Conclusion In the study population, patients with sickle cell disease treated with the standard dose of hydroxyurea treatment did not show evidence of DNA damage induction.

RESUMO Objetivo Avaliar o efeito da indução de danos ao DNA em células monocelulares do sangue periférico de pacientes com doença falciforme, genótipos SS e SC, tratados com hidroxiureia. Métodos Os sujeitos da pesquisa foram divididos em dois grupos: um de 22 pacientes com doença falciforme genótipos SS e SC tratados com hidroxiureia, e o outro controle, composto por 24 pacientes com doença falciforme que não eram tratados com o fármaco. As amostras de sangue periférico foram submetidas ao isolamento de células mononucleares do sangue periférico para avaliação da genotoxicidade pelo ensaio de micronúcleo citoma com bloqueio da citocinese, tendo sido quantificados os biomarcadores de danos ao DNA - micronúcleos, pontes nucleoplasmáticas e brotamento nuclear. Resultados Os pacientes com doença falciforme tratados com hidroxiureia apresentaram média de idade de 25,4 anos, enquanto aqueles com doença falciforme não tratados com hidroxiureia tiveram média de idade de 17,6 anos. A dose média de hidroxiureia utilizada pelos pacientes foi de 12,8mg/kg/dia, por período médio de 44 meses. A frequência média de micronúcleos por 1.000 células de 8,591±1,568 foi observada no Grupo Hidroxiureia e de 10,040±1,003 no Grupo Controle. Adicionalmente, a frequência média de pontes nucleoplasmáticas por 1.000 células e brotamento nuclear por 1.000 células para o Grupo Hidroxiureia e Controle foi de 0,4545±0,1707 versus 0,5833±0,2078, e de 0,8182±0,2430 versus 0,9583±0,1853, respectivamente. Não houve diferença estatisticamente significativa entre os grupos. Conclusão Na população estudada de pacientes com doença falciforme com tratamento em dose padrão de hidroxiureia, não houve evidência de indução de danos ao DNA.

Effect of wheatgrass on DNA damage, oxidative stress index and histological findings in diabetic rats / Efecto del pasto de trigo sobre el daño del ADN, el índice de estrés oxidativo y los hallazgos histológicos en ratas diabéticas

This study was aimed to search the effect of wheatgrass on the Total Antioxidan (TAS)-Oxidan Status (TOS) and DNA damage in rat with diabetes. The rats used in the study were randomly divided into 4 groups that each of has 10 rats: Control group; 1 ml single dose phosphate-citrate buffer injected i.p (pH: 4.5), Diabetes group; 45 mg/kg single dose streptozotocin injected i.p., Wheatgrass group; was given oral wheatgrass (10 ml/kg/day) for 6 weeks, Diabetes +Wheatgrass group; 45 mg/kg single dose streptozotocin injected i.p. and wheatgrass (10 ml/kg/day) was given by oral during 6 weeks. After the process of experiment during 6 weeks, blood sample and pancreas tissue were taken. The analysis were done of blood glucose levels, TAS, TOS levels by colorimetric kits; DNA damage by ELISA kits in serum. The pancreas tissues were examined histopathologically. In the group of Diabetes+Wheatgrass was determined that the levels of glucose levels (p<0.001), TOS (p<0.05) and OSI (p<0.01) statistically decreased and heal histopatolojical compared to diabetes group. In the group of Wheatgrass was determined that the levels of TAS p<0.05 statistically increased from other groups. The statistical significance were not found in the level of serum 8OHdG differences between the groups. The beta cells were seen to increase in the group receiving wheatgrass for therapeutic purposes.As a conclusion, it was determined that wheatgrass strengthened the anti-oxidant defense system and reduced the glucose level in diabetic rats.

El objetivo de este estudio fue buscar el efecto del pasto de trigo sobre el estado total de antioxidantes (TAS) -Oxidan Status (TOS) y el daño del ADN en ratas con diabetes. Las ratas analizadas en el estudio se dividieron aleatoriamente en 4 grupos de 10 ejemplares cada uno: grupo control; 1 ml de tampón fosfato-citrato de dosis única inyectado i.p. (pH: 4,5)., Grupo diabetes; 45 mg / kg de estreptozotocina en dosis única inyectada i.p., grupo pasto de trigo; se administró pasto de trigo oral (10 ml / kg / día) durante 6 semanas, grupo diabetes + pasto de trigo; 45 mg / kg de estreptozotocina en dosis única inyectada i.p. y pasto de trigo (10 ml / kg / día) por vía oral durante 6 semanas. Después del proceso experimental durante 6 semanas, se tomaron muestras de sangre y tejido de páncreas. Se midieron los niveles de glucosa en sangre, TAS, y TOS mediante kits colorimétricos; El daño al ADN fue realizado por kits de ELISA en suero. Los tejidos del páncreas se examinaron histopatológicamente. En el grupo de diabetes + pasto de trigo se determinó que los niveles de glucosa (p <0,001), TOS (p <0,05) y OSI (p <0,01) disminuyeron estadísticamente y curaron histopatológicamente en comparación con el grupo de diabetes. En el grupo de pasto de trigo se determinó que los niveles de TAS p <0,05 se incrementaron estadísticamente con respecto a otros grupos. No fue estadísticamente significativo el nivel de las diferencias séricas de 8OHdG entre los grupos. Se observó que las células beta aumentaron en el grupo que recibió pasto de trigo con fines terapéuticos. Como conclusión, se determinó que el pasto de trigo fortaleció el sistema de defensa antioxidante y redujo el nivel de glucosa en las ratas diabéticas.

Reduction of doxorubicin-induced genotoxicity by Handroanthus impetiginosus in mouse bone marrow revealed by micronucleus assay / Redução da genotoxicidade induzida pela doxorrubicina por Handroanthus impetiginosus na medula óssea de camundongos revelada pelo ensaio do micronúcleo

Abstract Handroanthus impetiginosus has long been used in traditional medicine and various studies have determined the presence of bioactive chemical compounds and potential phytotherapeutics. In this study, the genotoxicity of the lyophilized tincture of H. impetiginosus bark (THI) was evaluated in mouse bone marrow using micronucleus assays. The interaction between THI and genotoxic effects induced by the chemotherapeutic agent, doxorubicin (DXR), was also analyzed. Experimental groups were evaluated 24 to 48 h after treatment with N-nitroso-N-ethylurea (NEU; 50 mg/kg), DXR (5 mg/kg), sodium chloride (NaCl; 150 mM), and THI (0.5-2 g/kg). Antigenotoxic assays were carried out using THI (0.5 g/kg) in combination with NEU or DXR. Analysis of the micronucleated polychromatic erythrocytes (MNPCEs) indicated no significant differences between treatment doses of THI (0.5-2 g/kg) and NaCl. Polychromatic erythrocyte (PCE) to normochromatic erythrocyte (NCE) ratios did not indicate any statistical differences between DXR and THI or NaCl, but there were differences between THI and NaCl. A significant reduction in MNPCEs and PCE/NCE ratios was observed when THI was administered in combination with DXR. This study suggested the absence of THI genotoxicity that was dose-, time-, and gender-independent and the presence of moderate systemic toxicity that was dose-independent, but time- and gender-dependent. The combination of THI and DXR also suggested antigenotoxic effects, indicating that THI reduced genotoxic effects induced by chemotherapeutic agents.

Resumo Handroanthus impetiginosus tem sido usada durante um longo período pela medicina tradicional e vários estudos têm demonstrados a presença de compostos químicos e potencial fitoterapêutico. Esta pesquisa avaliou a genotoxicidade da tintura da casca liofilizada de H. impetiginosus (THI) usando o ensaio do micronúcleo em medula óssea de camundongos. A interação entre THI e os efeitos genotóxicos induzidos pelo quimioterápico doxorrubicina (DXR) também foram analisados. Grupos experimentais foram analisados a 24-48 h após o tratamento com N-Nitroso-N-etiluréia (NEU; 50 mg/kg), DXR (5 mg/kg), NaCl (150 mM) e THI (0,5-2 g/kg). O ensaio antigenotóxico foi conduzido utilizando THI (0,5 g/kg) em combinação com NEU ou DXR. A análise de eritrócitos policromáticos micronucleados (EPCMNs) não mostrou diferenças significativas entre as doses de tratamento (0,5-2 g/kg) e NaCl. As proporções de eritrócitos policromáticos (EPC)/eritrócitos normocromáticos (ENC) não revelaram diferenças estatísticas entre DXR e THI ou NaCl, porém houve diferenças entre THI e NaCl. Uma redução significativa em EPCMNs e na razão EPC/ENC foi observada quando THI foi administrado em combinação com DXR. Essa pesquisa sugere ausência de genotoxicidade de THI, dose-, tempo- e sexo-independente, e moderada toxicidade sistêmica dose-independente, mas tempo- e sexo-dependente. A associação do THI e DXR também sugere efeitos antigenotóxicos. Por conseguinte, THI pode reduzir os efeitos genotóxicos induzidos pelo quimioterapêutico.

Cuban flora species as a potential source of DNA protective compounds / Especies de la flora cubana cómo fuente potencial de compuestos protectores del DNA

Environmental exposure to genotoxic agents represents a major health concern for modern society. DNA damage could lead to mutations, which accumulative effect is closely related to degenerative and lethal diseases, such as cancer. Because of their structural and chemical diversity natural products play a fundamental role in pharmaceutical sciences for novel drug discovery. The present review article focuses on pre-clinical studies done with some species from Cuban flora that have been tested with positive antigenotoxic properties against different genotoxins. Special emphasis regarding molecular mechanisms suggested, from antioxidant activity to DNA repair modulation, a critical discussion of the state of art and the perspectives in the use of these plants as a new and promising strategy for genoprotection in the 21st Century are included.

La exposición ambiental a agentes genotóxicos representa un problema de salud significativo en la sociedad actual. El daño al ADN puede generar mutaciones, cuyo efecto acumulativo se encuentra estrechamente relacionado con enfermedades degenerativas y letales como el cáncer. Debido a su diversidad estructural y química los productos naturales juegan un papel fundamental en las ciencias farmacéuticas en el descubrimiento de nuevas drogas. El presente artículo de revisión puntualiza estudios pre-clínicos realizados con determinadas especies de la flora cubana que han sido estudiadas con una respuesta antioxidante positiva frente a diferentes genotoxinas. Se enfatizan especialmente los mecanismos moleculares sugeridos, desde actividad antioxidante hasta modulación de la reparación del ADN, así como una discusión crítica del estado del arte y las perspectivas en el empleo de estas plantas como una estrategia nueva y prometedora para la genoprotección en el siglo 21.

DNA repair pathways and cisplatin resistance: an intimate relationship

The main goal of chemotherapeutic drugs is to induce massive cell death in tumors. Cisplatin is an antitumor drug widely used to treat several types of cancer. Despite its remarkable efficiency, most tumors show intrinsic or acquired drug resistance. The primary biological target of cisplatin is genomic DNA, and it causes a plethora of DNA lesions that block transcription and replication. These cisplatin-induced DNA lesions strongly induce cell death if they are not properly repaired or processed. To counteract cisplatin-induced DNA damage, cells use an intricate network of mechanisms, including DNA damage repair and translesion synthesis. In this review, we describe how cisplatin-induced DNA lesions are repaired or tolerated by cells and focus on the pivotal role of DNA repair and tolerance mechanisms in tumor resistance to cisplatin. In fact, several recent clinical findings have correlated the tumor cell status of DNA repair/translesion synthesis with patient response to cisplatin treatment. Furthermore, these mechanisms provide interesting targets for pharmacological modulation that can increase the efficiency of cisplatin chemotherapy.

Oridonin induces growth inhibition and apoptosis in human gastric carcinoma cells by enhancement of p53 expression and function

The tumor suppressive role of oridonin, an active compound extracted from Rabdosia rubescens, has been proven in several gastric cancer (GC) cell lines. The present study aimed to evaluate the effect of oridonin on another GC cell line, SNU-216, and explore the potential mechanisms. The viable cell numbers, cell migration, survival fraction, and cell viability were, respectively, evaluated by trypan blue exclusion assay, wound healing assay, clonogenic assay, and CCK-8 assay. Cell apoptosis was determined by flow cytometry assay and western blot. The expression of p53 was inhibited by transient transfection, and the efficiency was verified by western blot. qRT-PCR was performed to measure the mRNA expression of p53. Western blot was used to evaluate the protein expression of apoptosis, DNA damage and p53 function related factors. We found that oridonin significantly inhibited cell proliferation, migration, and survivability, and enhanced cell apoptosis in SNU-216 cells. However, it had no influence on HEK293 cell viability. Oridonin also remarkably enhanced the anti-tumor effect of cisplatin on SNU-216 cells, as it significantly increased apoptotic cells and decreased cell viability. Moreover, the mRNA and protein expression of p53 was significantly up-regulated in oridonin-treated cells, while Mdm2 expression was down-regulated. Furthermore, oridonin enhanced p53 function and induced DNA damage. Knockdown of p53 or employing the caspase inhibitor, Boc-D-FMK, reversed the effect of oridonin on cell viability and apoptosis-related protein expression. The present study demonstrated that oridonin exhibited an anti-tumor effect on GC SNU-216 cells through regulating p53 expression and function.

Reduction of the DNA damages, Hepatoprotective Effect and Antioxidant Potential of the Coconut Water, ascorbic and Caffeic Acids in Oxidative Stress Mediated by Ethanol

ABSTRACT Hepatic disorders such as steatosis and alcoholic steatohepatitis are common diseases that affect thousands of people around the globe. This study aims to identify the main phenol compounds using a new HPLC-ESI+-MS/MS method, to evaluate some oxidative stress parameters and the hepatoprotective action of green dwarf coconut water, caffeic and ascorbic acids on the liver and serum of rats treated with ethanol. The results showed five polyphenols in the lyophilized coconut water spiked with standards: chlorogenic acid (0.18 µM), caffeic acid (1.1 µM), methyl caffeate (0.03 µM), quercetin (0.08 µM) and ferulic acid (0.02 µM) isomers. In the animals, the activity of the serum γ-glutamyltranspeptidase (γ-GT) was reduced to 1.8 I.U/L in the coconut water group, 3.6 I.U/L in the ascorbic acid group and 2.9 I.U/L in the caffeic acid groups, when compared with the ethanol group (5.1 I.U/L, p<0.05). Still in liver, the DNA analysis demonstrated a decrease of oxidized bases compared to ethanol group of 36.2% and 48.0% for pretreated and post treated coconut water group respectively, 42.5% for the caffeic acid group, and 34.5% for the ascorbic acid group. The ascorbic acid was efficient in inhibiting the thiobarbituric acid reactive substances (TBARS) in the liver by 16.5% in comparison with the ethanol group. These data indicate that the green dwarf coconut water, caffeic and ascorbic acids have antioxidant, hepatoprotective and reduced DNA damage properties, thus decreasing the oxidative stress induced by ethanol metabolism.

Comparisons of the effects of the sevoflurane and propofol on acute ischemia reperfusion and DNA damages in rabbits / Comparações dos efeitos de sevoflurano e propofol sobre isquemia-reperfusão aguda e danos ao DNA em coelhos

Abstract Background and objectives: The aim of this study was to compare the effects of sevoflurane and propofol anesthesia on oxidative DNA damage that occurs in low-extremity ischemia and is caused by tourniquet application. Methods: Fourteen New Zealand rabbits were randomly allocated into two equal groups. Group S (n = 7) received sevoflurane (2.5-4 percent) inhalation and Group P (n = 7) received a propofol infusion (1-2 mg·kg-1·min-1), after which a pneumatic tourniquet was placed on the right lower extremity. Blood samples were collected prior to tourniquet placement (baseline), 120 min after ischemia, 15 min after ischemia and 120 minutes (min) after ischemia. Malondialdehyde (MDA) levels were analyzed to determine lipid peroxidation, and single cell gel electrophoresis (SCGE) was used to determine DNA damage. Results: At 15 min after ischemia, the MDA levels in Group P (8.15 ± 2.61 µM) were higher than baseline (6.26 ± 3.19 µM, p = 0.026) and Group S (4.98 ± 0.77 µM, p = 0.01). DNA damage was similar in both groups, although DNA damage was higher than baseline (tail moment 0.63 ± 0.27, tail intensity 3.76 ± 1.26) in Group P at the 15th minute of reperfusion (tail moment 1.05 ± 0.45, p = 0.06; tail intensity 5.33 ± 1.56, p = 0.01). The increase in tail moment and tail intensity returned to normal levels in both groups 2 hours after the termination of ischemia. Conclusion: Given that oxidative stress and genotoxic effect disappear in the late stages of reperfusion, we conclude that neither sevoflurane nor propofol can be considered superior to the other in anesthesia practices for extremity surgeries involving the use of a tourniquet.

Resumo Justificativa e objetivos: Comparar os efeitos da anestesia com sevoflurano e propofol sobre o dano oxidativo ao DNA que ocorre na isquemia de extremidade inferior e é causada pela aplicação de torniquete. Métodos: Foram alocados aleatoriamente em dois grupos iguais 14 coelhos da raça Nova Zelândia. Grupo S (n = 7) recebeu inalação de sevoflurano (2,5-4%) e Grupo P (n = 7) recebeu perfusão de propofol (1-2 mg·kg-1·min-1), logo após um torniquete pneumático foi colocado na extremidade inferior direita. Amostras de sangue foram coletadas antes da colocação do torniquete (fase basal), após 120 minutos de isquemia, 15 minutos após a isquemia e 120 minutos após a isquemia. Os níveis de malondialdeído (MDA) foram analisados para determinar a peroxidação de lipídios e eletroforese em gel de célula única (EGCU) foi usada para determinar o dano ao DNA. Resultados: Aos 15 minutos após a isquemia, os níveis de MDA no Grupo P (8,15 ± 2,61 µM) foram superiores aos da fase basal (6,26 ± 3,19 µM, p = 0,026) e dp Grupo S (4,98 ± 0,77 µM, p = 0,01). O dano causado ao DNA foi semelhante nos dois grupos, embora tenha sido maior do que na fase basal (momento da cauda 0,63 ± 0,27, intensidade da cauda 3,76 ± 1,26) no Grupo P no 15 minutos de reperfusão (momento da cauda 1,05 ± 0,45, p = 0,06; intensidade da cauda 5,33 ± 1,56, p = 0,01). O aumento no momento da cauda e a intensidade da cauda voltaram aos níveis normais nos dois grupos duas horas após o término da isquemia. Conclusão: Como o estresse oxidativo e o efeito genotóxico desaparecem nos estágios finais da reperfusão, concluímos que não há superioridade tanto de sevoflurano quanto de propofol em práticas de anestesia para procedimentos cirúrgicos de extremidades que envolvem o uso de torniquete.

Protein carbonyl content: a novel biomarker for aging in HIV/AIDS patients

Abstract Background: The major complications of “treated” Human Immunodeficiency Virus (HIV) infection are cardiovascular disease, malignancy, renal disease, liver disease, bone disease, and perhaps neurological complications, which are phenomena of the normal aging process occurring at an earlier age in the HIV-infected population. The present study is aimed to explore protein carbonyl content as a biomarker for detecting oxidative DNA damage induced ART toxicity and/or accelerated aging in HIV/AIDS patients. Objective: To investigate the potential of carbonyl content as a biomarker for detecting oxidative Deoxyribonucleic acid (DNA) damage induced Antiretroviral Theraphy (ART) toxicity and/or accelerated aging in HIV/AIDS patients. Methods: In this case–control study a total 600 subjects were included. All subjects were randomly selected and grouped as HIV-negative (control group) (n = 300), HIV-infected ART naive (n = 100), HIV-infected on first line ART (n = 100), and HIV-infected on second line ART (n = 100). Seronegative control subjects were age- and sex-matched with the ART naive patients and the two other groups. Carbonyl protein was determined by the method described in Levine et al. DNA damage marker 8-OH-dG was determined using 8-hydroxy-2-deoxy Guanosine StressXpress ELA Kit by StressMarq Biosciences. Results: Protein carbonyl content levels and oxidative DNA damage were significantly higher (p < 0.05) in HIV-infected patients on second line ART and HIV-infected patients on first line ART than ART naive patients and controls. In a linear regression analysis, increased protein carbonyl content was positively associated with increased DNA damage (OR: 0.356; 95% CI: 0.287–0.426) p < 0.05. Conclusions: Carbonyl content may has a role as a biomarker for detecting oxidative DNA damage induced ART toxicity and/or accelerated aging in HIV/AIDS patients. Larger studies are warranted to elucidate the role of carbonyl content as a biomarker for premature aging in HIV/AIDS patients.

Vernonanthura polyanthes leaves aqueous extract enhances doxorubicin genotoxicity in somatic cells of Drosophila melanogaster and presents no antifungal activity against Candida spp / O extrato aquoso das folhas de Vernonanthura polyanthes potencializa a genotoxicidade da doxorrubicina em células somáticas de Drosophila melanogaster e não apresenta atividade antifúngica contra Candida spp

Abstract Vernonanthura polyanthes (Spreng.) A.J. Vega & Dematt. (Asteraceae), known as “assa-peixe”, has been used in ethnomedicine for the treatment of various diseases such as bronchitis, pneumonia, hemoptysis, persistent cough, internal abscesses, gastric and kidney stone pain. Moreover, some studies demonstrated that species of Genus Vernonia present antifungal activity. Due to the biological relevance of this species, the aim of this study was to investigate the toxic, genotoxic, antigenotoxic and antifungal potential of V. polyanthes leaves aqueous extract in somatic cells of Drosophila melanogaster or against Candida spp. The aqueous extract of the plant showed no toxic, genotoxic and antigenotoxic activity in the experimental conditions tested using the wing somatic mutation and recombination test (SMART/wing). However, when the extract was associated with doxorubicin, used in this work as a positive control, the mutagenic potential of doxorubicin was enhanced, increasing the number of mutations in D. melanogaster somatic cells. In the other hand, no inhibitory activity against Candida spp. was observed for V. polyanthes leaves aqueous extract using agar-well diffusion assay. More studies are necessary to reveal the components present in the V. polyanthes leaves aqueous extract that could contribute to potentiate the doxorubicin genotoxicity.

Resumo Vernonanthura polyanthes (Spreng.) A.J. Vega & Dematt. (Asteraceae), conhecida como “assa-peixe”, tem sido utilizada na medicina popular para o tratamento de várias doenças, como bronquite, pneumonia, hemoptise, tosse persistente, abcessos internos, afecções gástricas e cálculo renal. Além disso, alguns estudos já demonstraram que espécies do Gênero Vernonia apresentam atividade antifúngica. Devido à relevância biológica dessa espécie, o objetivo deste estudo foi investigar os efeitos citotóxico, genotóxico, antigenotóxico e antifúngico do extrato aquoso das folhas de V. polyanthes em células somáticas de Drosophila melanogaster ou contra Candida spp. O extrato aquoso da planta não apresentou atividade citotóxica, genotóxica e antigenotóxica nas condições experimentais testadas usando o teste de recombinação e mutação somática em asa (SMART-asa). No entanto, quando o extrato foi associado com a doxorrubicina, utilizada neste trabalho como controle positivo, o potencial mutagênico da doxorrubicina foi potencializado, aumentando o número de mutações em células somáticas de D. melanogaster. Por outro lado, nenhuma atividade inibitória contra Candida spp. foi observada utilizando o extrato aquoso das folhas de V. polyanthes por meio do método de difusão em ágar. Mais estudos são necessários para desvendar os componentes presentes no extrato aquoso das folhas de V. polyanthes que possam contribuir para potencializar a genotoxicidade da doxorrubicina.

Cobalt oxide nanoparticles aggravate DNA damage and cell death in eggplant via mitochondrial swelling and NO signaling pathway

BACKGROUND: Despite manifold benefits of nanoparticles (NPs), less information on the risks of NPs to human health and environment has been studied. Cobalt oxide nanoparticles (Co3O4-NPs) have been reported to cause toxicity in several organisms. In this study, we have investigated the role of Co3O4-NPs in inducing phytotoxicity, cellular DNA damage and apoptosis in eggplant (Solanum melongena L. cv. Violetta lunga 2). To the best of our knowledge, this is the first report on Co3O4-NPs showing phytotoxicity in eggplant. RESULTS: The data revealed that eggplant seeds treated with Co3O4-NPs for 2 h at a concentration of 1.0 mg/ml retarded root length by 81.5 % upon 7 days incubation in a moist chamber. Ultrastructural analysis by transmission electron microscopy (TEM) demonstrated the uptake and translocation of Co3O4-NPs into the cytoplasm. Intracellular presence of Co3O4-NPs triggered subcellular changes such as degeneration of mitochondrial cristae, abundance of peroxisomes and excessive vacuolization. Flow cytometric analysis of Co3O4-NPs (1.0 mg/ml) treated root protoplasts revealed 157, 282 and 178 % increase in reactive oxygen species (ROS), membrane potential (APm) and nitric oxide (NO), respectively. Besides, the esterase activity in treated protoplasts was also found compromised. About 2.4-fold greater level of DNA damage, as compared to untreated control was observed in Comet assay, and 73.2 % of Co3O4-NPs treated cells appeared apoptotic in flow cytometry based cell cycle analysis. CONCLUSION: This study demonstrate the phytotoxic potential of Co3O4-NPs in terms of reduction in seed germination, root growth, greater level of DNA and mitochondrial damage, oxidative stress and cell death in eggplant. The data generated from this study will provide a strong background to draw attention on Co3O4-NPs environmental hazards to vegetable crops.

Evaluation of the genotoxicity and mutagenicity of Ca3SiO5-based cement

Abstract Ca3SiO5 is new cement based on the composition of Portland that has been developed to have superior physicochemical and biological properties. In a clinical evaluation, the cement did not appear to have cytotoxic properties and allowed for the proliferation of pulp cells and gingival fibroblasts. However, no previous studies have evaluated the genotoxicity or the mutagenicity of Ca3SiO5in vivo. Therefore, the goal of this study is to evaluate the genotoxic and mutagenic potential of Ca3SiO5-based cement in vivo. Twenty-four male Wistar rats were divided into 3 groups (n = 8). Group A rats received subcutaneous implantation of Ca3SiO5 in the dorsum. Group B rats received a single dose of cyclophosphamide (positive control). Group C rats received subcutaneous implantation of empty tubes in the dorsum (negative control). After 24 hours, all animals were euthanized and the bone marrow of the femurs was collected for use in the comet assay and the micronucleus test. The comet assay revealed that the Ca3SiO5 group had a tail intensity of 23.57 ± 7.70%, the cyclophosphamide group had a tail intensity of 27.43 ± 7.40%, and the negative control group had a tail intensity of 24.75 ± 5.55%. The average number of micronuclei was 6.25 (standard deviation, SD = 3.53) in the Ca3SiO5 group, 9.75 (SD = 2.49) in the cyclophosphamide group, and 0.75 (SD = 1.03) in the negative control group. There was an increase in the micronuclei frequency in the Ca3SiO5 group compared to that of the negative control group (p < 0.05). Our data showed that exposure to the Ca3SiO5-based cement resulted in an increase in the frequency of micronuclei, but no genotoxicity was detected according to the comet assay.

Is the Linear No-Threshold Dose-Response Paradigm Still Necessary for the Assessment of Health Effects of Low Dose Radiation?

Inevitable human exposure to ionizing radiation from man-made sources has been increased with the proceeding of human civilization and consequently public concerns focus on the possible risk to human health. Moreover, Fukushima nuclear power plant accidents after the 2011 East-Japan earthquake and tsunami has brought the great fear and anxiety for the exposure of radiation at low levels, even much lower levels similar to natural background. Health effects of low dose radiation less than 100 mSv have been debated whether they are beneficial or detrimental because sample sizes were not large enough to allow epidemiological detection of excess effects and there was lack of consistency among the available experimental data. We have reviewed an extensive literature on the low dose radiation effects in both radiation biology and epidemiology, and highlighted some of the controversies therein. This article could provide a reasonable view of utilizing radiation for human life and responding to the public questions about radiation risk. In addition, it suggests the necessity of integrated studies of radiobiology and epidemiology at the national level in order to collect more systematic and profound information about health effects of low dose radiation.

Caryocar brasiliense camb protects against genomic and oxidative damage in urethane-induced lung carcinogenesis

The antioxidant effects of Caryocar brasiliense Camb, commonly known as the pequi fruit, have not been evaluated to determine their protective effects against oxidative damage in lung carcinogenesis. In the present study, we evaluated the role of pequi fruit against urethane-induced DNA damage and oxidative stress in forty 8-12 week old male BALB/C mice. An in vivo comet assay was performed to assess DNA damage in lung tissues and changes in lipid peroxidation and redox cycle antioxidants were monitored for oxidative stress. Prior supplementation with pequi oil or its extract (15 µL, 60 days) significantly reduced urethane-induced oxidative stress. A protective effect against DNA damage was associated with the modulation of lipid peroxidation and low protein and gene expression of nitric oxide synthase. These findings suggest that the intake of pequi fruit might protect against in vivo genotoxicity and oxidative stress.

Studies of genotoxicity and mutagenicity of nitroimidazoles: demystifying this critical relationship with the nitro group

Nitroimidazoles exhibit high microbicidal activity, but mutagenic, genotoxic and cytotoxic properties have been attributed to the presence of the nitro group. However, we synthesised nitroimidazoles with activity against the trypomastigotes of Trypanosoma cruzi, but that were not genotoxic. Herein, nitroimidazoles (11-19) bearing different substituent groups were investigated for their potential induction of genotoxicity (comet assay) and mutagenicity (Salmonella/Microsome assay) and the correlations of these effects with their trypanocidal effect and with megazol were investigated. The compounds were designed to analyse the role played by the position of the nitro group in the imidazole nucleus (C-4 or C-5) and the presence of oxidisable groups at N-1 as an anion receptor group and the role of a methyl group at C-2. Nitroimidazoles bearing NO2 at C-4 and CH3 at C-2 were not genotoxic compared to those bearing NO 2 at C-5. However, when there was a CH3 at C-2, the position of the NO2 group had no influence on the genotoxic activity. Fluorinated compounds exhibited higher genotoxicity regardless of the presence of CH3 at C-2 or NO2 at C-4 or C-5. However, in compounds 11 (2-CH3; 4-NO2; N-CH2OHCH2Cl) and 12 (2-CH3; 4-NO2; N-CH2OHCH2F), the fluorine atom had no influence on genotoxicity. This study contributes to the future search for new and safer prototypes and provide.

Caffeic acid improves cell viability and protects against DNA damage: involvement of reactive oxygen species and extracellular signal-regulated kinase

Hormesis is an adaptive response to a variety of oxidative stresses that renders cells resistant to harmful doses of stressing agents. Caffeic acid (CaA) is an important antioxidant that has protective effects against DNA damage caused by reactive oxygen species (ROS). However, whether CaA-induced protection is a hormetic effect remains unknown, as is the molecular mechanism that is involved. We found that a low concentration (10 μM) of CaA increased human liver L-02 cell viability, attenuated hydrogen peroxide (H2O2)-mediated decreases in cell viability, and decreased the extent of H2O2-induced DNA double-strand breaks (DSBs). In L-02 cells exposed to H2O2, CaA treatment reduced ROS levels, which might have played a protective role. CaA also activated the extracellular signal-regulated kinase (ERK) signal pathway in a time-dependent manner. Inhibition of ERK by its inhibitor U0126 or by its specific small interfering RNA (siRNA) blocked the CaA-induced improvement in cell viability and the protective effects against H2O2-mediated DNA damage. This study adds to the understanding of the antioxidant effects of CaA by identifying a novel molecular mechanism of enhanced cell viability and protection against DNA damage.