RESUMO
Background: Several studies have showed that animal venoms are a source of bioactive compounds that may inhibit the growth of cancer cells, which makes them useful agents for therapeutic applications. Recently, it was established that venom toxins from scorpions induced cytotoxic, antiproliferative and apoptogenic effects on cancer cells. Therefore, the present study aims to investigate the cytotoxic activity of Androctonus australis hector (Aah) scorpion venom and its toxic fractions (FtoxG-50 and F3) on NCI-H358 human lung cancer cells. Methods: The cytotoxic and antiproliferative activities were estimated using MTT assay, lactate dehydrogenase release and clonogenic assays. Apoptosis was evaluated by Hoechst 33258 staining, DNA fragmentation assay and caspase-3 activity. Oxidative stress was analyzed by reactive oxygen species, nitric oxide, malondialdehyde and protein carbonyl levels along with assessment of antioxidant status. In addition, alteration of mitochondrial membrane potential was analyzed by JC1 fluorescent dye. Results: The present findings showed that F3 fraction was more cytotoxic towards NCI-H358 lung cancer cells with an IC50 of 27.05 ± 0.70 μg/mL than venom alone (396.60 ± 1.33 μg/mL) and its toxic fraction FtoxG-50 (45.86 ± 0.91 μg/mL). Nevertheless, F3 fraction was not cytotoxic at these concentrations on normal human lung fibroblast MRC-5 cells. Inhibition of NCI-H358 cell proliferation after F3 fraction exposure occurred mainly by apoptosis as evidenced by damaged nuclei, significant DNA fragmentation level and caspase-3 activation in a dose dependent manner. Moreover, F3 fraction enhanced oxidative and nitrosative stress biomarkers and dissipated mitochondrial membrane potential in lung cancer cells along with significant depletion in cellular enzymatic and non-enzymatic antioxidants. Further, the apoptosis induced by F3 fraction was markedly prevented by the antioxidant N-acetylcysteine (NAC) suggesting the potential mechanism of oxidative stress. Conclusion: These findings suggest that F3 fraction could induce apoptosis in lung cancer cells through involvement of oxidative stress and mitochondrial dysfunction. Hence, these properties make F3 fraction a promising candidate for development of new anticancer agents.(AU)
Assuntos
Humanos , Biomarcadores , Linhagem Celular , Apoptose , Estresse Oxidativo , Androctonus , Proliferação de Células , Bisbenzimidazol , Neoplasias Pulmonares , Óxido NítricoRESUMO
El objetivo de este trabajo fue evaluar la incidencia de micoplasmas contaminantes de cultivos celulares y de reactivos empleados en su propagación, obtenida de siete laboratorios, durante un período de 15 años. En este lapso se procesaron 568 muestras, correspondientes a: 403 pases de cultivos celulares, 47 lotes de sueros, 112 de medios de cultivo y 6 de soluciones de tripsina. Los métodos utilizados fueron: microbiológicos para el 100 por ciento de las muestras; 46 líneas fueron procesadas simultáneamente por la técnica de tinción del ADN mediante fluorocromos (DAPI y compuesto Hoechst-33258) y 20 por microscopía electrónica de transmisión. Los resultados demostraron una mayor incidencia de contaminación durante el primer quinquenio, con un 65,18 por ciento , disminuyendo progresivamente en el segundo y tercero, con el 38,66 y 21,18 por ciento respectivamente. Consideramos de gran importancia la vigilancia epidemiológica en este sentido, por las graves consecuencias que acarrea a los cultivos celulares la contaminación por micoplasmas
