Browsing by Author "Pinheiro, C."
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- Hypoxia-mediated upregulation of MCT1 expression supports the glycolytic phenotype of glioblastomasPublication . Miranda-Gonçalves, V.; Granja, S.; Martinho, O.; Honavar, M.; Pojo, M.; Costa, B.; Melo-Pires, M.; Pinheiro, C.; Cordeiro, M.; Bebiano, G.; Costa, P.; Reis, R.; Baltazar, F.BACKGROUND: Glioblastomas (GBM) present a high cellular heterogeneity with conspicuous necrotic regions associated with hypoxia, which is related to tumor aggressiveness. GBM tumors exhibit high glycolytic metabolism with increased lactate production that is extruded to the tumor microenvironment through monocarboxylate transporters (MCTs). While hypoxia-mediated regulation of MCT4 has been characterized, the role of MCT1 is still controversial. Thus, we aimed to understand the role of hypoxia in the regulation of MCT expression and function in GBM, MCT1 in particular. METHODS: Expression of hypoxia- and glycolytic-related markers, as well as MCT1 and MCT4 isoforms was assessed in in vitro and in vivo orthotopic glioma models, and also in human GBM tissues by immunofluorescence/immunohistochemistry and Western blot. Following MCT1 inhibition, either pharmacologically with CHC (α-cyano-4-hydroxynnamic acid) or genetically with siRNAs, we assessed GBM cell viability, proliferation, metabolism, migration and invasion, under normoxia and hypoxia conditions. RESULTS: Hypoxia induced an increase in MCT1 plasma membrane expression in glioma cells, both in in vitro and in vivo models. Additionally, treatment with CHC and downregulation of MCT1 in glioma cells decreased lactate production, cell proliferation and invasion under hypoxia. Moreover, in the in vivo orthotopic model and in human GBM tissues, there was extensive co-expression of MCT1, but not MCT4, with the GBM hypoxia marker CAIX. CONCLUSION: Hypoxia-induced MCT1 supports GBM glycolytic phenotype, being responsible for lactate efflux and an important mediator of cell survival and aggressiveness. Therefore, MCT1 constitutes a promising therapeutic target in GBM.
- IMPORTÂNCIA DA CITOMETRIA DE FLUXO NA AVALIAÇÃO DE LESÕES CEREBRAIS SUSPEITAS DE LINFOMAPublication . Campos, F.; Bini-Antunes, M.; Santos, A.; Queirós, M.; Santos, M.; Gonçalves, M.; Fonseca, S.; Lau, C.; Teixeira, M.; Nunes, P.; Pinheiro, C.; Pires, M.; Lima, M.A citometria de fluxo (CF) tem adquirido um papel cada vez maior no diagnóstico e classificação das patologias linfoproliferativas, sendo fundamental a integração e complementaridade das informações obtidas por citometria com os resultados do estudo anatomo-patológico (EAP). Existem, porém, escassas referências na literatura que documentem a importância da CF na avaliação de lesões cerebrais suspeitas de linfoma.
- LINFOMA PRIMÁRIO DO SISTEMA NERVOSO CENTRAL: REVISÃO IMAGIOLÓGICA DE CASUÍSTICA HOSPITALARPublication . Nunnes, P.; Ramos, C.; Pinheiro, C.; Carvalho, E.; Cruz, R.
- Unraveling the pathogenesis of ARX polyalanine tract variants using a clinical and molecular interfacing approachPublication . Marques, I.; Sá, J.; Soares, G.; Mota, M.; Pinheiro, C.; Aguiar, L.; Amado, M.; Soares, C.; Calado, A.; Dias, P.; Sousa, A.; Fortuna, A.; Santos, R.; Howell, K.; Ryan, M.; Leventer, R.; Sachdev, R.; Catford, R.; Friend, K; Mattiske, T.; Shoubridge, C.; Jorge, P.The Aristaless-related homeobox (ARX) gene is implicated in intellectual disability with the most frequent pathogenic mutations leading to expansions of the first two polyalanine tracts. Here, we describe analysis of the ARX gene outlining the approaches in the Australian and Portuguese setting, using an integrated clinical and molecular strategy. We report variants in the ARX gene detected in 19 patients belonging to 17 families. Seven pathogenic variants, being expansion mutations in both polyalanine tract 1 and tract 2, were identifyed, including a novel mutation in polyalanine tract 1 that expands the first tract to 20 alanines. This precise number of alanines is sufficient to cause pathogenicity when expanded in polyalanine tract 2. Five cases presented a probably non-pathogenic variant, including the novel HGVS: c.441_455del, classified as unlikely disease causing, consistent with reports that suggest that in frame deletions in polyalanine stretches of ARX rarely cause intellectual disability. In addition, we identified five cases with a variant of unclear pathogenic significance. Owing to the inconsistent ARX variants description, publications were reviewed and ARX variant classifications were standardized and detailed unambiguously according to recommendations of the Human Genome Variation Society. In the absence of a pathognomonic clinical feature, we propose that molecular analysis of the ARX gene should be included in routine diagnostic practice in individuals with either nonsyndromic or syndromic intellectual disability. A definitive diagnosis of ARX-related disorders is crucial for an adequate clinical follow-up and accurate genetic counseling of at-risk family members.