Análise morfo-funcional dos modos de ação de peptídeos mastoparanos em células de glioblastoma multiforme
Arquivos
Data
2017-08-31
Autores
Silva, Annielle Mendes Brito da 
Orientadores
Miranda Filho, Manoel de Arcisio
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Glioblastoma multiforme é o mais frequente e letal dos tumores malignos que atingem o cérebro. Por causa da sua complexidade e heterogeneidade, este tumor se tornou resistente às terapias convencionais, além dos múltiplos efeitos adversos. Desta forma, a ciência vem procurando novas alternativas eficazes e menos danosas para o tratamento do glioblastoma multiforme. Mastoparanos são peptídeos de origem animal que possuem diversas atividades biológicas, dentre elas, vem destacando-se o potencial citotóxico contra vários tipos de células cancerosas. Neste estudo, foram realizados estudos morfofuncionais para avaliar como quatro peptídeos mastoparanos - Anoplin, Polybia-MP1, Mastoparan X e HR1 -, com diferentes características físico-químicas, exercem atividade citotóxica sobre as células de linhagem T98G, de glioblastoma multiforme humano. Os resultados indicaram que três destes peptídeos induziram significativa redução da viabilidade celular, promovendo alterações em parâmetros morfológicos, como redução da área celular e da área nuclear. Os ensaios para avaliação do tipo de morte celular apresentaram um grande número de células com significativa marcação de iodeto de propídio, também evidenciada em ensaios de microscopia de fluorescência, mostrando que os mastoparanos possuem atividade membranolítica e pró-necrótica. Com o uso de sondas fluorescentes específicas, foi possível analisar que os mastoparanos são capazes de se inserir membrana das células de GBM humano, modulando a sua fluidez em diferentes posições. Em complemento, os resultados de experimentos com sistemas miméticos de membrana evidenciaram que o aumento do conteúdo aniônico presente na face externa das membranas contribui proporcionalmente para o aumento da atividade dos peptídeos mastoparanos. Também foi verificado que, além das cargas de superfície, o efeito do campo elétrico criado pela distribuição diferencial de íons entre os meios intra- e extracelular é capaz de alterar a atividade do peptídeo MPX.
Glioblastoma multiforme is the most frequent and lethal malignant tumor that reaches the brain. Because of its complexity and heterogeneity, this tumor has become resistant to conventional therapies in addition to the multiple adverse effects. In this way, science nas been looking for new, effective and less harmful alternatives for the treatment of glioblastoma multiforme. Mastoparans are peptides from animal origin that have several biological activities, among them, the cytotoxic potential against several types of cancer cells has been highlighted. In this study, morphofunctional studies were performed to evaluate how four mastoparan peptides - Anoplin, Polybia-MP1, Mastoparan X and HR1 -, with different physicochemical characteristics, exert cytotoxic activity on T98G cells of human glioblastoma multiforme. The results indicated that three of these peptides induced a significant reduction in cell viability, promoting changes in morphological parameters, such as reduction of cell and nuclear area. Assay to investigate the type of cell death showed a large number of cells marked withf propidium iodide, also evidenced in fluorescence microscopy assays, showing that the mastoparans have membranolytic .,l.. and pro-necrotic activity. With the use of specific fluorescent probes, it was possible to analyze that the mastoparans are able to insert in human GBM cells membrane, modulating their fluidity in different positions. In addition, the results of experiments with membrane mimetic systems showed that the increase of the anionic content present on the outer face of the membranes contributes proportionally to the increase of the mastoparan peptides activity. It has also been verified that in addition to surface charges, the effect of the electric field created by the differential distribution of ions between the intra- and extracellular media is capable of altering MPX peptide activity.
Glioblastoma multiforme is the most frequent and lethal malignant tumor that reaches the brain. Because of its complexity and heterogeneity, this tumor has become resistant to conventional therapies in addition to the multiple adverse effects. In this way, science nas been looking for new, effective and less harmful alternatives for the treatment of glioblastoma multiforme. Mastoparans are peptides from animal origin that have several biological activities, among them, the cytotoxic potential against several types of cancer cells has been highlighted. In this study, morphofunctional studies were performed to evaluate how four mastoparan peptides - Anoplin, Polybia-MP1, Mastoparan X and HR1 -, with different physicochemical characteristics, exert cytotoxic activity on T98G cells of human glioblastoma multiforme. The results indicated that three of these peptides induced a significant reduction in cell viability, promoting changes in morphological parameters, such as reduction of cell and nuclear area. Assay to investigate the type of cell death showed a large number of cells marked withf propidium iodide, also evidenced in fluorescence microscopy assays, showing that the mastoparans have membranolytic .,l.. and pro-necrotic activity. With the use of specific fluorescent probes, it was possible to analyze that the mastoparans are able to insert in human GBM cells membrane, modulating their fluidity in different positions. In addition, the results of experiments with membrane mimetic systems showed that the increase of the anionic content present on the outer face of the membranes contributes proportionally to the increase of the mastoparan peptides activity. It has also been verified that in addition to surface charges, the effect of the electric field created by the differential distribution of ions between the intra- and extracellular media is capable of altering MPX peptide activity.
Descrição
Citação
SILVA, Annielle Mendes Brito da. Análise morfo-funcional dos modos de ação de peptídeos mastoparanos em células de glioblastoma multiforme. São Paulo, 2017. [131] p. Tese (Doutorado em Ciências biológicas: biologia molecular) - Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, 2017.