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000790294.pdf: 2780767 bytes, checksum: 07f6082eb9b1ea8f07a04e4c107bdeac (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O câncer de mama apresenta altas taxas de incidência e mortalidade, sendo a neoplasia mais comum entre as mulheres. O rápido crescimento do tumor resulta em hipóxia no microambiente tumoral, levando a uma cascata de eventos que induzem a angiogênese e conseqüente progressão do câncer. Assim, a identificação de agentes terapêuticos que possam inibir a angiogênese é essencial para o controle da progressão tumoral. Nesse sentido, tem sido demonstrado que a administração exógena da melatonina, um hormônio naturalmente secretado pela glândula pineal, apresenta diversos efeitos oncostáticos em diferentes tipos de câncer. Assim, o objetivo desse estudo foi avaliar a efetividade do tratamento com melatonina sobre a angiogênese do câncer de mama, em estudos in vitro e in vivo. No estudo in vitro, as linhagens de câncer de mama MCF-7 e MDA-MB-231 foram tratadas com melatonina sob condições de hipóxia mimetizadas pelo Cloreto de Cobalto (CoCl2). A viabilidade celular foi verificada pelo ensaio MTT, a expressão do fator de transcrição induzido por hipóxia (HIF-1α) e do fator de crescimento endotelial vascular (VEGF-A) foi avaliada por PCR em tempo real e imunocitoquímica. Além disso, demais proteínas envolvidas na angiogênese foram avaliadas por Protein Array. No estudo in vivo, as células MDA-MB-231 foram implantadas em camundongos nude atímicos, os quais foram tratados com melatonina (40 mg/kg) por 21 dias. O tumor foi medido semanalmente e a avaliação da angiogênese foi realizada pela técnica de tomografia computadorizada por emissão de fóton único (SPECT), com o radiotraçador Tc- 99m-HYNIC-VEGF-c, agente específico para os receptores de VEGF (VEGFR2/VEGF3). Além disso, as proteínas VEGFR2, VEGFR3, fator de fator de von Willebrand (vWF) e marcador de proliferação celular (Ki-67) foram avaliados no tecido tumoral por imuno-histoquímica, e demais proteínas angiogênicas por Protein Array. O estudo in ... / Breast cancer has high rates of incidence and mortality, and it is the most common cancer among women. The rapid tumor growth results in hypoxia on tumor microenvironment, leading to a cascade of events that induce angiogenesis and subsequent cancer progression. Thus, the identification of therapeutic agents that can inhibit angiogenesis is essential for the control of tumor progression. Exogenous administration of melatonin, a hormone secreted by the pineal gland, has been shown several oncostatics effects on different types of cancers. The aim of this study was to evaluate the effectiveness of melatonin treatment on angiogenesis in breast cancer, in the in vitro and in vivo studies. In the in vitro study, breast cancer cell lines (MCF-7 and MDA-MB-231) were treated with melatonin under cobalt chloride (CoCl2)-induced hypoxic conditions. Cell viability was measured by MTT assay, the expression of hypoxia-inducible factor 1-alpha (HIF-1α) and vascular endothelial growth factor (VEGF-A) was assessed by real-time PCR and immunocytochemistry. Additionally, other proteins involved in angiogenesis were evaluated by the Protein Array. In the in vivo study, the MDA-MB-231 cells were implanted in athymic nude mice, which were treated with melatonin (40 mg/kg) for 21 days. The tumor was measured weekly and evaluation of angiogenesis was performed by single-photon emission computed tomography (SPECT) with Tc-99m-HYNIC-VEGF-c, which is specific for VEGF receptors (VEGFR2/VEGF3). Moreover, VEGFR2, VEGFR3, von Willebrand factor (vWF) and cell proliferation marker (Ki-67) were evaluated in tumor tissue by immunohistochemistry, and other angiogenic proteins by Protein Array. Results from the in vitro study showed that 1 mM of melatonin under hypoxic conditions (200 μM CoCl2) led to decreased cell viability, protein levels of HIF- 1α and gene and protein expression of VEGF-A in both cell lines (p < 0.05). Among other proteins evaluated, melatonin ...
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.unesp.br:11449/110553 |
| Date | 26 May 2014 |
| Creators | Jardim-Perassi, Bruna Victorasso [UNESP] |
| Contributors | Universidade Estadual Paulista (UNESP), Zuccari, Debora Aparecida Pires de Campos [UNESP] |
| Publisher | Universidade Estadual Paulista (UNESP) |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | 122 f. : il. color., tabs. |
| Source | Aleph, reponame:Repositório Institucional da UNESP, instname:Universidade Estadual Paulista, instacron:UNESP |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -1, -1 |
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