Avaliação da angiogênese em resposta ao tratamento com melatonina no câncer de mama: estudo in vitro e in vivo

Detalhes bibliográficos
Ano de defesa: 2014
Autor(a) principal: Jardim-Perassi, Bruna Victorasso [UNESP]
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Tese
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Estadual Paulista (Unesp)
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://hdl.handle.net/11449/110553
Resumo: 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 ...