ABSTRACT
OBJECTIVES. The ANKRD1 gene codes for the ankyrin repeat domain containing protein 1 and has an important role in myogenesis and possibly also in angiogenesis. Microvasculopathy is a cornerstone and an early pathological marker of change in dermatomyositis, leading to hypoxia and muscle perifascicular atrophy. These alterations could upregulate genes involved in myogenesis and angiogenesis such as ANKRD1. Therefore, we analyzed ANKRD1 expression in muscle biopsies of dermatomyositis and correlated with other hypoxia parameters and with histological changes. METHODS. Total RNA was extracted from frozen muscle biopsies samples of 29 dermatomyositis patients. A control group consisted of 20 muscle biopsies from adult patients with non-inflammatory myopathy diseases. The gene coding for hypoxia-inducible factor 1, alpha subunit (HIF1A), was analyzed to estimate the degree of hypoxia. ANKRD1 and HIF1A transcript expression levels were determined by quantitative real time PCR. RESULTS. Significantly higher ANKRD1 and HIF1A expression levels were observed in dermatomyositis relative to the control group (P<0.001, both genes). In addition, ANKRD1 and HIF1A were coexpressed (r=0.703, P=0.001) and their expression levels correlated positively to perifascicular atrophy (r=0.420, P=0.023 and r=0.404, P=0.030, respectively). CONCLUSIONS. Our results demonstrate ANKRD1 overexpression in dermatomyositis correlated to HIF1A expression and perifascicular atrophy. ANKRD1 involvement in myogenesis and angiogenesis mechanisms indicates that further investigation is worthwhile.
OBJETIVOS: ANKRD1 codifica "ankyrin repeat domain containing protein 1" e tem um papel importante na miogênese e possivelmente também na angiogênese. Microvasculopatia é considerada como um ponto central e uma alteração patológica precoce na dermatomiosite (DM), levando à hipóxia e à atrofia perifascicular muscular. Estas alterações poderiam estimular genes envolvidos na miogênese e angiogênese como ANKRD1. Portanto, analisamos a expressão de ANKRD1 em biópsias musculares de DM e correlacionamos com outros parâmetros de hipóxia e alterações histológicas. MÉTODOS: O RNA total foi extraído de biópsias de músculos congelados de 29 pacientes com DM. Como grupo controle, foram usadas 20 biópsias de músculo de pacientes adultos com miopatia não-inflamatória. O gene que codifica a subunidade alfa do fator 1 induzido por hipóxia (HIF1A) foi analisado para estimar o grau de hipóxia. Os níveis de expressão dos transcritos ANKRD1 e HIF1A foram determinados por PCR quantitativa em tempo real. RESULTADOS: Níveis aumentados de expressões de ANKRD1 e HIF1A foram observados em DM quando comparados ao grupo controle (P<0,001, ambos os genes). Além disso, ANKRD1 e HIF1A apresentaram coexpressão (r=0,703, P=0,001) e seus níveis de expressão correlacionaram-se também positivamente com atrofia perifascicular (r=0,420, P=0,023 e r=0,404, P=0,030, respectivamente). CONCLUSÕES: Nossos resultados demonstraram aumento de expressão de ANKRD1 na DM, que correlacionou com a expressão de HIF1A e atrofia perifascicular. Investigações adicionais do envolvimento de ANKRD1 no mecanismo de miogênese e angiogênese devem ser realizadas.
Subject(s)
Humans , RNA/analysis , Muscle Development , Dermatomyositis/physiopathology , HypoxiaABSTRACT
OBJECTIVE: ASCT2 and LAT1 are aminoacid transporters involved in glutamine transport and play a role in tumor growth. Previous studies have shown an association of ASCT2 to cell proliferation through the mechanistic Target of Rapamycin (mTOR) translational machinery; LAT1 has been shown as a prognostic marker due to its relation to tumor invasion, microscopic vascular invasion and metastasis. This study analyzed the gene expression of ASCT2 and LAT1 in astrocytomas of different grades and how this correlates to clinical outcome in glioblastoma patients. METHOD: This is an observational study with ASCT2 and LAT1 mRNA expression analysis in 153 samples of human astrocytomas, distributed in different World Health Organization (WHO) grades of malignancy (23 at grade I or pilocytic astrocytoma, 26 at grade II or low-grade astrocytoma, 18 at grade III or anaplastic astrocytoma, 86 at grade IV astrocytoma or glioblastoma (AGIV or GBM)); these were compared to 22 non-neoplastic brain samples. RESULTS: Significant hyperexpression of both genes was observed particularly in malignant astrocytomas (GIII & GBM). Moreover, LAT1 hyperexpression impacted negatively in the overall survival in a subset of GBM patients. CONCLUSION: LAT1 is more expressed in higher grade astrocytomas. It leads to a poorer prognosis among GBM patients and may be a potential therapeutical target.
OBJETIVO: ASCT2 e LAT1 são transportadores de aminoácidos envolvidos no transporte de glutamina e desempenham um papel no crescimento tumoral. Estudos prévios mostraram uma associação de ASCT2 com proliferação celular através da maquinaria de tradução do mTOR; tem sido mostrado que o LAT1 é um marcador prognóstico devido à sua relação com invasão tumoral, invasão vascular microscópica e metástase. Este estudo analisou a expressão gênica de ASCT2 e LAT1 em astrocitomas de diferentes graus e sua correlação com desfecho clínico em pacientes com glioblastoma. METODO: Este é um estudo observacional com análise de expressão de RNAm de ASCT2 e LAT1 em 153 amostras de astrocitomas humanos, distribuídas em diferentes graus de malignidade segundo a OMS (23 astrocitomas de grau I ou astrocitoma pilocítico, 26 de astrocitoma de grau II ou astrocitoma de baixo grau, 18 de astrocitoma de grau III ou astrocitoma anaplásico, 86 de astrocitoma de grau IV ou glioblastoma (AGIV ou GBM); estes foram comparados com 22 amostras cerebrais não neoplásicas. RESULTADOS: Foi observada uma hiperexpressão de ambos os genes, particularmente nos astrocitomas malignos (GIII & GBM). Além disso, a hiperexpressão LAT1 impactou negativamente na sobrevida global em um grupo de pacientes com GBM. CONCLUSÃO: LAT1 é mais expresso em astrocitomas de grau maior. Isso leva a um pior prognóstico entre os pacientes com GBM e pode ser um potencial alvo terapêutico.
Subject(s)
Humans , Astrocytoma , Gene Expression , Glioblastoma/pathology , Large Neutral Amino Acid-Transporter 1/analysis , GlutamineABSTRACT
OBJECTIVES: We investigated four components of the Wnt signaling pathway in medulloblastomas. Medulloblastoma is the most common type of malignant pediatric brain tumor, and the Wnt signaling pathway has been shown to be activated in this type of tumor. METHODS: Sixty-one medulloblastoma cases were analyzed for β-catenin gene (CTNNB1) mutations, β-catenin protein expression via immunostaining and Wnt signaling pathway-related gene expression. All data were correlated with histological subtypes and patient clinical information. RESULTS: CTNNB1 sequencing analysis revealed that 11 out of 61 medulloblastomas harbored missense mutations in residues 32, 33, 34 and 37, which are located in exon 3. These mutations alter the glycogen synthase kinase-3β phosphorylation sites, which participate in β-catenin degradation. No significant differences were observed between mutation status and histological medulloblastoma type, patient age and overall or progression-free survival times. Nuclear β-catenin accumulation, which was observed in 27.9% of the cases, was not associated with the histological type, CTNNB1 mutation status or tumor cell dissemination. The relative expression levels of genes that code for proteins involved in the Wnt signaling pathway (CTNNB1, APC, AXIN1 and WNT1) were also analyzed, but no significant correlations were found. In addition, large-cell variant medulloblastomas presented lower relative CTNNB1 expression as compared to the other tumor variants. CONCLUSIONS: A small subset of medulloblastomas carry CTNNB1 mutations with consequent nuclear accumulation of β-catenin. The Wnt signaling pathway plays a role in classic, desmoplastic and extensive nodularity medulloblastoma variants but not in large-cell medulloblastomas.
Subject(s)
Adult , Child , Female , Humans , Male , Adenomatous Polyposis Coli Protein/analysis , Axin Protein/analysis , Cerebellar Neoplasms/pathology , Medulloblastoma/pathology , beta Catenin/analysis , Adenomatous Polyposis Coli Protein/metabolism , Axin Protein/metabolism , Chi-Square Distribution , Cerebellar Neoplasms/genetics , Cerebellar Neoplasms/metabolism , Disease-Free Survival , Gene Expression , Medulloblastoma/genetics , Medulloblastoma/metabolism , Real-Time Polymerase Chain Reaction , Statistics, Nonparametric , Wnt Signaling Pathway , beta Catenin/metabolismABSTRACT
OBJECTIVES: 1) To correlate the methylation status of the O6-methylguanine-DNA-methyltransferase (MGMT) promoter to its gene and protein expression levels in glioblastoma and 2) to determine the most reliable method for using MGMT to predict the response to adjuvant therapy in patients with glioblastoma. BACKGROUND: The MGMT gene is epigenetically silenced by promoter hypermethylation in gliomas, and this modification has emerged as a relevant predictor of therapeutic response. METHODS: Fifty-one cases of glioblastoma were analyzed for MGMT promoter methylation by methylation-specific PCR and pyrosequencing, gene expression by real time polymerase chain reaction, and protein expression by immunohistochemistry. RESULTS: MGMT promoter methylation was found in 43.1 percent of glioblastoma by methylation-specific PCR and 38.8 percent by pyrosequencing. A low level of MGMT gene expression was correlated with positive MGMT promoter methylation (p = 0.001). However, no correlation was found between promoter methylation and MGMT protein expression (p = 0.297). The mean survival time of glioblastoma patients submitted to adjuvant therapy was significantly higher among patients with MGMT promoter methylation (log rank = 0.025 by methylation-specific PCR and 0.004 by pyrosequencing), and methylation was an independent predictive factor that was associated with improved prognosis by multivariate analysis. DISCUSSION AND CONCLUSION: MGMT promoter methylation status was a more reliable predictor of susceptibility to adjuvant therapy and prognosis of glioblastoma than were MGMT protein or gene expression levels. Methylation-specific polymerase chain reaction and pyrosequencing methods were both sensitive methods for determining MGMT promoter methylation status using DNA extracted from frozen tissue.
Subject(s)
Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Brain Neoplasms/genetics , DNA Modification Methylases/genetics , DNA Repair Enzymes/genetics , Glioblastoma/genetics , Promoter Regions, Genetic/genetics , Tumor Suppressor Proteins/genetics , Brain Neoplasms/metabolism , DNA Methylation , DNA Modification Methylases/metabolism , DNA Repair Enzymes/metabolism , Gene Expression , Glioblastoma/metabolism , Immunohistochemistry , Kaplan-Meier Estimate , Polymerase Chain Reaction , Predictive Value of Tests , Prognosis , Statistics, Nonparametric , Time Factors , Tumor Suppressor Proteins/metabolismABSTRACT
Alterações de TP53, estão associadas com a maioria dos cânceres, incluindo tumores do sitema nervoso central(SNC). Astrocitomas difusos são as neoplasias intracranianas mais frequentes perfazendo cerca de 60 por cento de todos os tumores primários do SNC. As mutações de TP53 são observadas em aproximadamente 30 a 40 por cento de todos os graus de astrocitomas difusos / TP53 alterations, are associated to a large number of human cancers, including central nervous system (CNS) tumors. Diffuse astrocytomas are the most frequent intracranial neoplasms and account for approximately 30 a 40 per cent of all three grades of diffuse astrocytoma, sugggesting that inactivation...