Orientadora: Profa. Dra. Ana Carolina Santos de Souza Galvão / Nanoparticulas derivadas de oxidos metalicos, em suas formas livres ou associadas a moleculas organicas ou drogas antineoplasicas, tem sido empregadas no diagnostico e tratamento do cancer. Neste cenario, destaca-se o uso de oxidos nanoestruturados derivados de zinco. Recentes estudos demonstraram a capacidade de nanoparticulas de ZnO, individualmente ou em associacao a agentes quimioterapicos, de sensibilizacao de celulas tumorais resistentes a multiplas drogas (fenotipo MDR), que possuem em sua membrana proteinas de efluxo que impedem o acumulo destas drogas no interior das celulas. A falta de seletividade e dificuldade de internalizacao pelas celulas de alguns compostos utilizados no tratamento de cancer, sao considerados os maiores empecilhos para o tratamento quimioterapico, tornando a modificacao da superficie de materiais nanoestruturados com atividade antitumoral, atraves da funcionalizacao, forma de aumentar a incorporacao e consequente atividade citotoxica destes compostos em celulas tumorais. Neste trabalho, as nanoparticulas foram funcionalizadas com L-glutamina, devido a grande importancia deste aminoacido no metabolismo de celulas cancerigenas e ao fato destas apresentarem maior captacao desse aminoacido que celulas nao tumorais. A citotoxicidade de nanoparticulas funcionalizadas com L-glutamina ou nao funcionalizadas foi avaliada em celulas de leucemia mieloide cronica K562 e sua versao com fenotipo MDR Lucena-1. A atividade citotoxica de ZnO foi comprovada pelos ensaios de exclusao de Trypan Blue e reducao de MTT, com IC50 de 20 evalencia de dupla marcacao nas celulas K562 tratadas com as nanoparticulas ZnO e ZnO_Gln, enquanto que para Lucena-1 observou-se porcentagens semelhantes de celulas duplamente marcadas e marcadas apenas com Anexina V. Para avaliar se ha influencia de especies reativas de oxigenio (EROs), geradas peLucena-1. Atraves das analises das possiveis vias de morte celular via analise de Western Blotting, estudando principalmente as proteinas e os eventos envolvidos no processo de morte celular programada (Bcl2, Bad, Bid, Caspase-3 e PARP) e autofagia (Beclin-1 e P62), observou-se que mais de uma via de morte foi ativada nas celulas tratadas com as nanoparticulas, o que corrobora com o descrito em literatura, considerando autofagia e apoptose sao as principais vias de morte ativadas pela acao citotoxica das nanoparticulas de ZnO. Outro evento observado foi a alteracao da atividade da proteina PgPieloide cronica K562 e a linhagem com fenotipo MDR Lucena-1 e a utilizacao deste aminoacido na funcionalizacao de nanomateriais pode ser uma importante ferramenta a ser explorada. / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Biossistemas, 2015. / Nanoparticles derived from metal oxides, in their free forms or associated with organic molecules or antineoplastic drugs, have been employed in the diagnosis and treatment of cancer. In this scenario, we highlight the use of zinc-based nanostructured oxides. Recent studies demonstrated the ability of ZnO nanoparticles, alone or in combination with chemotherapeutic agents, sensitization of tumor cells multidrug resistant (MDR phenotype), which have on their membrane efflux proteins that prevent the accumulation of these drugs within cells. The lack of selectivity, and difficulty internalization by cells of some compounds used in the treatment of cancer, are considered the major obstacles to chemotherapy, making the nanostructured surface modification of materials having anti-tumor activity through the functionalization way to increase the cytotoxic activity and subsequent incorporation of these compounds in tumor cells. In this work, the nanoparticles were functionalized with L-glutamine, due to the great importance of this amino acid in cancer cell metabolism and the fact that these have higher uptake of this amino acid to non-tumor cells. The cytotoxicity of nanoparticles functionalized with L-glutamine functionalized or not was evaluated in chronic myelogenous leukemia cells K562 and its version with MDR phenotype-Lucena 1. The cytotoxic activity of ZnO was confirmed by Trypan Blue exclusion and MTT reduction assays, with IC50 of 20 d K562 with ZnO nanoparticles and ZnO_Gln, while for Lucena-1 was observed similar percentages of doubly labeled cells and marked only with Annexin V. To assess whether there is influence of reactive oxygen species (ROS) generated by nanoparticles of ZnO and ZnO_Gln in their cytotoxic activity in ceC promoted protection against the cytotoxicity of nanoparticles even in higher concentrations of nanoparticles (30 ug / ml) in both the lines cell. In the potentiation of cell death caused by ZnO nanoparticles in cell lines studied, functionalization with L-glutamine promoted greater incorporation o562 cells treated with pure functionalized nanoparticles and in relation to the control compared to cells of Lucena-1 strain. Through analysis of the possible ways of cell death via Western blot analysis, the proteins and particularly studying the events involved in programmed cell death (Bcl2, Bad, Bid, caspase-3 and PARP) and autophagy (beclin-1 and P62), there was more than one death pathway was activated in cells treated with nanoparticles, which corroborates with what is described in literature, considering autophagy and apoptosis are the main routes of death activated cytotoxic action ofytotoxic effect of ZnO in the chronic myelogenous leukemia line K562 and the line Lucena MDR-1 phenotype and use this amino acid in the functionalization of nanomaterials can be an important tool to be exploited.
| Identifer | oai:union.ndltd.org:IBICT/oai:BDTD:77242 |
| Date | January 2015 |
| Creators | Santos Neto, Manoel Domingos dos |
| Contributors | Galvão, Ana Carolina Santos de Souza, Araujo, Daniele Ribeiro, Giacomelli, Fernando Carlos, Jesus, Marcelo Bispo de, Chaves Neto, Antonio Hernandes |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf, 117 f. : il. |
| Source | reponame:Repositório Institucional da UFABC, instname:Universidade Federal do ABC, instacron:UFABC |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | http://biblioteca.ufabc.edu.br/index.php?codigo_sophia=77242&midiaext=70611, http://biblioteca.ufabc.edu.br/index.php?codigo_sophia=77242&midiaext=70612, Cover: http://biblioteca.ufabc.edu.brphp/capa.php?obra=77242 |
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