Project description:Gene expression data generated for the purpose of correlating differentially-expressed genes between IDH1 mutant and IDH1 wild-type high grade gliomas with differential hydroxymethylcytosine profiles as determined using Illumina EPIC BeadChip platform.
Project description:The discovery of the IDH1 R132H (IDH1 mut) mutation in low-grade glioma and the associated change in function of the IDH1 enzyme has increased the interest in glioma metabolism. In an earlier study, we found that changes in expression of genes involved in the aerobic glycolysis and the TCA-cycle are associated with IDH1 mut. Here we apply proteomics to FFPE samples of diffuse gliomas with or without IDH1 mutations, in order to map changes in protein levels associated with this mutation. We observed significant changes in the enzyme abundance associated with aerobic glycolysis, glutamate metabolism and the TCA-cycle in IDH1 mut gliomas. Specifically, the enzymes involved in the metabolism of glutamate, lactate and enzymes involved in the conversion of α-ketoglutarate were increased in IDH1 mut gliomas. In addition, the bicarbonate transporter (SLC4A4) was increased in IDH1 mut gliomas, supporting the idea that a mechanism preventing intracellular acidification is active. We also found that enzymes that convert proline, valine, leucine and isoleucine into glutamate were increased in IDH1 mut glioma. We conclude that in IDH1 mut glioma metabolism is rewired (increased input of lactate and glutamate) to preserve TCA cycle activity in IDH1 mut gliomas.
Project description:The discovery of the IDH1 R132H (IDH1 mut) mutation in low-grade glioma and the associated change in function of the IDH1 enzyme has increased the interest in glioma metabolism. In an earlier study, we found that changes in expression of genes involved in the aerobic glycolysis and the TCA-cycle are associated with IDH1 mut. Here we apply proteomics to FFPE samples of diffuse gliomas with or without IDH1 mutations, in order to map changes in protein levels associated with this mutation. We observed significant changes in the enzyme abundance associated with aerobic glycolysis, glutamate metabolism and the TCA-cycle in IDH1 mut gliomas. Specifically, the enzymes involved in the metabolism of glutamate, lactate and enzymes involved in the conversion of α-ketoglutarate were increased in IDH1 mut gliomas. In addition, the bicarbonate transporter (SLC4A4) was increased in IDH1 mut gliomas, supporting the idea that a mechanism preventing intracellular acidification is active. We also found that enzymes that convert proline, valine, leucine and isoleucine into glutamate were increased in IDH1 mut glioma. We conclude that in IDH1 mut glioma metabolism is rewired (increased input of lactate and glutamate) to preserve TCA cycle activity in IDH1 mut gliomas.
Project description:20% of patients affected with diffuse low-grade brain tumors have high cell density foci harboring higher KI67 index and DNA alterations. These foci may represent tumor progression towards high-grade gliomas. Here we performed transcriptome analysis of those foci vs adjacent tumoral tissues dissected from formalin fixed and paraffin embedded blocks.
Project description:Gliomas harboring mutations in isocitrate dehydrogenase 1/2 (IDH1/2) have the CpG island methylator phenotype (CIMP) and significantly longer patient survival time than wild-type IDH1/2 tumors. Although there are many factors underlying the differences in survival between these two tumor types, immune-related differences in cell content are potentially important contributors. In order to investigate the role of IDH mutations in immune response, we created a syngeneic pair mouse model for mutated IDH1 (mutIDH1) and wild-type IDH1 (wtIDH1) gliomas and demonstrated that muIDH1 mice showed many molecular and clinical similarities to muIDH1 human gliomas, including a 100-fold higher concentration of 2-hydroxygluratate (2-HG), longer survival time, and higher CpG methylation compared to wtIDH1. Also, we showed that IDH1 mutations caused downregulation of leukocyte chemotaxis, resulting in repression of the tumor-associated immune system. Given that significant infiltration of immune cells such as macrophages, microglia, monocytes, and neutrophils is linked to poor prognosis in many cancer types, these reduced immune infiltrates in muIDH1 glioma tumors may contribute in part to the differences in aggressiveness of the two glioma types.
Project description:We carried out the analyses of chromosome variations between low-grade and high-grade gliomas in Chinese population. We found out the differences in chromosomes, cytobands, genes, pathways and GO functions. To identify the glioma tissue-specific genomic alterations and compare the genomic variations between low-grade and high-grade gliomas.
Project description:Low grade gliomas (LGG; WHO grade 2 astrocytomas, oligodendrogliomas and oligoastrocytomas) account for about 25% of diffuse gliomas. Most occur in young adults between the ages of 30 and 45 years, and are usually only diagnosed after a seizure. In general, they can be characterised by a long period of continuous slow growth, followed by malignant transformation that will be the cause of death up to 25 years after onset. However, there is a significant number of patients for whom malignant progression is more rapid, with mortality observed within 5 years. This suggests that, as with other tumour types, there may be different subtypes of LGG with specific prognosis. It follows that being able to identify these subtypes may permit better patient stratification and aid targeted treatments. Until recently, our understanding of the variables involved in patient prognosis included the type of tumour oligodendroglial tumours indicate better prognosis than oligoastrocytic or astrocytic and presence of the 1p-19q co-deletion. In addition, the recent discovery of mutations in IDH1&2 in the majority of LGGs provided another means of stratifying patients, while offering an important insight into their biology. However, we still understand very little of the biology behind the genesis and progression of the 70-80% of LGG that bear IDH1&2 mutations, let alone the remaining IDH wild-type tumours.
Project description:In this study we performed gene expression profiling of 14 cases of grade II gliomas. The results of these analysis were used in unsupervised analyses to compare correlations between the histological subtype of grade II gliomas and gene expression profiles Total RNA was isolated from 14 tumor tissue of patients, which included 5 astrocytomas WHO grade II (T2), 5 oligodendro-gliomas WHO grade II (T2) and 4 ependymomas WHO grade II (T2) samples, in additional to 4 normal tissues. The genome-wide expression analysis was first performed by directly comparing the expression profile of highly enriched different kinds of grade II gliomas and normal tissues, we then applied various data-mining methods to process the 14 different types of grade II gliomas tissues sample.