Expressão de caspase-3 e Bcl-2 em glioblastomas: um estudo imunohistoquímico

The unfavorable prognosis of malignant gliomas can also be explained by the incomplete knowledge of their molecular pathways. Studies regarding the regulatory process of apoptosis in glioblastoma (GBM), the most common malignant glioma, are few, and better knowledge of the expression of pro and anti-apoptotic proteins could collaborate with the development of new treatments founded on molecular basis. The objective of this study was to evaluate by immunohistochemistry the expression of caspase-3 and Bcl-2 in 30 samples of GBMs. The expression of caspase-3 (mean 17.67%) was lower than Bcl-2 (mean 30.92%), a statistically significant result (p<0.0001), suggesting low apoptotic activity in these tumors. Other studies of proteins related to the intrinsic and extrinsic pathway of apoptosis are required to provide additional information of this mechanism in GBMs.O prognóstico desfavorável dos gliomas malignos também pode ser explicado pelo pouco conhecimento dos seus mecanismos moleculares. Estudos relacionados à regulação do processo de apoptose em glioblastoma (GBM), o glioma maligno mais comum, são poucos, e o melhor conhecimento da expressão de proteínas pró e anti-apoptóticas poderia colaborar com o desenvolvimento de novos tratamentos fundamentados sobre a base molecular. O objetivo deste estudo foi avaliar por imunohistoquímica, a expressão de caspase-3 e Bcl-2 em 30 amostras de GBM. A expressão de caspase-3 (média de 17,67%) foi menor que a de Bcl-2 (média de 30,92%), com resultado estatisticamente significante (p<0.0001), sugerindo menor atividade apoptótica nestes tumores. Outros estudos envolvendo proteínas relacionadas à via extrínseca e intrínseca da apoptose são necessários para fornecer informações complementares deste mecanismo em GBMs

Fas, FasL, and cleaved caspases 8 and 3 in glioblastomas: A tissue microarray-based study

This investigation analyzed the immunoexpression of FasL, Fas, cleaved caspase-8, and cleaved caspase-3 in glioblastomas. Formalin-fixed and paraffin-embedded glioblastoma tissues and control brain tissues from 97 patients were analyzed by tissue microarrays and immunohistochemistry. Patients with glioblastomas that were negative or weakly stained (<50% of cells positive) for cleaved caspase-8 had worse cancer-specific overall survival (median=8.5 months) than did patients with tumors that highly expressed cleaved caspase-8 (median=11.7 months; P=0.0325), independent of clinical variables. There was no association of other markers with survival, treatment, sex, age, tumor size, and primary site. Among the tumors, there were reasonable to good positive correlations between the expression of FasL and Fas (r=0.47) and between Fas and cleaved caspase-8 (r=0.41), and there were poor positive correlations between Fas and cleaved caspase-3 (r=0.26), FasL and cleaved caspase-8 (r=0.22), and cleaved caspase-8 and -3 (r=0.31). Our results suggest that Fas-Fas-ligand signal transduction could be inhibited, especially at the stage of caspase-8 activation, thereby establishing a major mechanism for evasion of apoptosis by these tumors. the absence or low expression of cleaved caspase-8 in the tumors was a negative prognostic indicator for patient survival. (C) 2014 Elsevier GmbH. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ São Paulo FMRR USP, Fac Med Ribeirao Preto, Dept Pathol, Ribeirao Preto, SP, BrazilUniversidade Federal de São Paulo UNIFESP EPM, Dept Pathol, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP EPM, Dept Neurol, São Paulo, BrazilHosp Canc AC Camargo, Dept Pathol, São Paulo, BrazilUniv São Paulo FMRP USP, Fac Med Ribeirao Preto, Dept Surg, Ribeirao Preto, SP, BrazilUniversidade Federal de São Paulo UNIFESP EPM, Dept Pathol, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP EPM, Dept Neurol, São Paulo, BrazilFAPESP: 04/09932-4Web of Scienc