Cytotoxicity and genotoxicity of low doses of mercury chloride and methylmercury chloride on human lymphocytes in vitro

Mercury is a xenobiotic metal that is a highly deleterious environmental pollutant. The biotransformation of mercury chloride (HgCl2) into methylmercury chloride (CH3HgCl) in aquatic environments is well-known and humans are exposed by consumption of contaminated fish, shellfish and algae. The objective of the present study was to determine the changes induced in vitro by two mercury compounds (HgCl2 and CH3HgCl) in cultured human lymphocytes. Short-term human leukocyte cultures from 10 healthy donors (5 females and 5 males) were set-up by adding drops of whole blood in complete medium. Cultures were separately and simultaneously treated with low doses (0.1 to 1000 µg/l) of HgCl2 and CH3HgCl and incubated at 37ºC for 48 h. Genotoxicity was assessed by chromosome aberrations and polyploid cells. Mitotic index was used as a measure of cytotoxicity. A significant increase (P < 0.05) in the relative frequency of chromosome aberrations was observed for all concentrations of CH3HgCl when compared to control, whether alone or in an evident sinergistic combination with HgCl2. The frequency of polyploid cells was also significantly increased (P < 0.05) when compared to control after exposure to all concentrations of CH3HgCl alone or in combination with HgCl2. CH3HgCl significantly decreased (P < 0.05) the mitotic index at 100 and 1000 µg/l alone, and at 1, 10, 100, and 1000 µg/l when combined with HgCl2, showing a synergistic cytotoxic effect. Our data showed that low concentrations of CH3HgCl might be cytotoxic/genotoxic. Such effects may indicate early cellular changes with possible biological consequences and should be considered in the preliminary evaluation of the risks of populations exposed in vivo to low doses of mercury.Faculdade de Itaituba Departamento de Pós-GraduaçãoUniversidade Federal do Pará Centro de Ciências Biológicas Departamento de BiologiaUniversidade Federal do Pará Centro de Ciências Biológicas Departamento de PatologiaUniversidade de São Paulo Faculdade de Medicina de Ribeirão Preto Departamento de GenéticaFundação Universidade Federal de Rondônia Departamento de Medicina Laboratório de Biogeoquímica AmbientalUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de MorfologiaUNIFESP, EPM, Depto. de MorfologiaSciEL

Effect of diterpenoid kaurenoic acid on genotoxicity and cell cycle progression in gastric cancer cell lines

The goal of our study was to evaluate the effect of kaurenoic acid, obtained from copaiba oil resin, in gastric cancer (GC) and a normal mucosa of stomach (MNP01) cell lines. The compound was tested at concentrations of 2.5, 5, 10, 30 and 60 mu g/mL. Comet and micronucleus assays were used to access its potential genotoxicity in vitro. Moreover, we evaluated the effect of kaurenoic acid in cell cycle progression and in the transcription of genes involved in the control of the cell cycle: MYC, CCND1, BCL2, CASP3, ATM, CHK2 and TP53. Kaurenoic acid induced an increase on cell DNA damage or micronucleus frequencies on GC cell lines in a dose-dependent manner. The GC and MNP01 cell lines entering DNA synthesis and mitosis decreased significantly with kaurenoic acid treatment, and had an increased growth phase compared with non-treated cells. The treatment induced apoptosis (or necrosis) even at a concentration of 2.5 mu g/mL in relation to non-treated cells. GC cell lines presented reduced MYC, CCND1, BCL2 and CASP3 transcription while ATM, CHK2 and TP53 increased in transcription in relation to nontreated cells, especially at a concentration above 10 mu g/mL. The gene transcription in the MNP01 (nontreated non-cancer cell line) was designated as a calibrator for all the GC cell lines. In conclusion, our results showed that kaurenoic acid obtained from Copaifera induces DNA damage and increases the micronuclei frequency in a dose-dependent manner in GC cells, with a significant genotoxicity observed above the concentration of 5 mu g/mL. Moreover, this compound seems to be able to induce cell cycle arrest and apoptosis in GC cells. (C) 2017 Elsevier Masson SAS. All rights reserved.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fed Univ Para UFPA, Biol Sci Inst, Human Cytogenet Lab, Belem, Para, BrazilFed Inst Educ Sci & Technol Para IFPA, Av Almirante Barroso,1155 Marco, BR-66093020 Belem, Para, BrazilFed Univ Sao Paulo UNIFESP, Dept Morphol & Genet, Sao Paulo, SP, BrazilUniv Franca UNIFRAN, Lab Genet & Mol Biol, Franca, SP, BrazilUniv Franca UNIFRAN, Lab Biotransformat, Franca, SP, BrazilFed Univ Ceara UFC, Dept Physiol & Pharmacol, Fortaleza, Ceara, BrazilFed Univ Ceara UFC, Lab Genet Hemoglobinopathies & Hematol Dis, Fortaleza, Ceara, BrazilHosp Ophir Loyola, Av Magalhaes Barata 992, BR-66060281 Belem, Para, BrazilFed Univ Sao Paulo UNIFESP, Dept Morphol & Genet, Sao Paulo, SP, BrazilWeb of Scienc

Genotoxic effect of Physalis angulata L. (Solanaceae) extract on human lymphocytes treated in vitro

Physalis angulata L (Solanaceae) is a medicinal plant from North of Brazil, whose different extracts and infusions are commonly used in the popular medicine for the treatment of malaria, asthma, hepatitis, dermatitis and rheumatism. However, the genotoxic effects of P. angulata on human cells is not well known. The main purpose of the present study was to evaluate the in vitro genotoxic effects of aqueous extract of P angulata using the comet assay and the micronucleus assay in human lymphocytes provided from 6 healthy donors. Treatments with P angulata extracts were performed in vitro in order to access the extent of DNA damage. The comet assay has shown that treatments with P angulata at 0.5, 1.0, 2.0, 3.0 and 6.0 mu g/mL in Culture medium were genotoxic. Lymphocytes treated with P angulata at the concentrations of 3.0 and 6.0 mu g/mL in culture medium showed a statistically significant increase in the frequency of micronucleus (p<0.05), however, the cytokinesis blocked proliferation index (CBPI) was not decreased after P angulata treatment. In conclusion, the present work demonstrated the genotoxic effects of P angulata extract on human lymphocytes in vitro.Conselho Nacional de Desenvolvimento Clentifico e Tecnologico (CNPq)[308256/2006-9]BIC/FAPEMIG (Fundacao de Amparo a Pesquisa do Estado de Minas Gerais

Cytogenetic biomonitoring of inhabitants of a large uranium mineralization area: the municipalities of Monte Alegre, Prainha, and Alenquer, in the State of Para, Brazil

Uranium is a natural radioactive metallic element; its effect on the organism is cumulative, and chronic exposure to this element can induce carcinogenesis. Three cities of the Amazon region-Monte Alegre, Prainha, and Alenquer-in North Brazil, are located in one of the largest uranium mineralization areas of the world. Radon is a radioactive gas, part of uranium decay series and readily diffuses through rock. In Monte Alegre, most of the houses are built of rocks removed from the Earth`s crust in the forest, where the uranium reserves lie. The objective of the present work is to determine the presence or absence of genotoxicity and risk of carcinogenesis induced by natural exposure to uranium and radon in the populations of these three cities. The frequency of micronuclei (MN) and chromosomal aberrations (CA) showed no statistically significant differences between the control population and the three study populations (P > 0.05). MN was also analyzed using the fluorescence in situ hybridization (FISH) technique, with a centromere-specific probe. No clastogenic and/or aneugenic effects were found in the populations. Using FISH analysis, other carcinogenesis biomarkers were analyzed, but neither the presence of the IGH/BCL2 translocation nor an amplification of the MYC gene and 22q21 region was detected. Clastogenicity and DNA damage were also not found in the populations analyzed using the alkaline comet assay. The mitotic index showed no cytotoxicity in the analyzed individuals` lymphocytes. Once we do not have data concerning radiation doses from other sources, such as cosmic rays, potassium, thorium, or anthropogenic sources, it is hard to determine if uranium emissions in this geographic region where our study population lives are too low to cause significant DNA damage. Regardless, genetic analyses suggest that the radiation in our study area is not high enough to induce DNA alterations or to interfere with mitotic apparatus formation. It is also possible that damages caused by radiation doses undergo cellular repair.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[409826/206-5]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[308256/2006-9