Project description:Early passages (< 10) of frequently used GBM cell lines A172, LN18, LN229, T98G, U87-MG, U138-MG and U251-MG were characterised for genomic copy number by array CGH.
Project description:Copy number analysis of human GBM samples were performed, and a high frequency of deletions of the PTPRD gene on chromosome 9p23-24.1 were identified. Keywords: SNP microarray, glioblastoma multiforme, copy number, amplification, deletion
Project description:Copy number analysis of human GBM samples were performed, and a high frequency of deletions of the PTPRD gene on chromosome 9p23-24.1 were identified. Keywords: SNP microarray, glioblastoma multiforme, copy number, amplification, deletion Genomic DNA from 58 GBM tumor samples were hybridized to Affymetrix 250K NspI Gene Chip Arrays and analyzed by dChip using the hg17 genome assembly.
Project description:Glioblastoma multiforme (GBM) is a highly heterogeneous disease that shows an wide range of genetic abnormalities in comparison to other astrocytic tumors. We have extracted between 4 and 8 tumor subsamples from different areas of the malignant tissue that were at least 1cm apart. Our aim to asses the intra-tumoral heterogeneity by comparing copy number aberrations in different tumor areas to uncover important dynamics underlying GBM progression.
Project description:Development of model systems that recapitulate the molecular heterogeneity observed amongst GBM tumors will expedite the testing of targeted molecular therapeutic strategies for GBM treatment. In this study, we profiled DNA copy number and mRNA expression in 21 independent GBM tumor lines maintained as subcutaneous xenografts (GBMX), and compared GBMX molecular signatures to those observed in GBM clinical specimens derived from The Cancer Genome Atlas (TCGA). The predominant copy number signature in both tumor groups was defined by chromosome-7-gain/chromosome-10-loss, a poor prognosis genetic signature. We also observed, at frequencies similar to that detected in TCGA GBMs genomic amplification and overexpression of known GBM oncogenes such as EGFR, MDM2, CDK6 and MYCN, and novel genes including NUP107, SLC35E3, MMP1, MMP13 and DDX1. The transcriptional signature of GBMX tumors, which was stable over multiple subcutaneous passages, was defined by overexpression of genes involved in M-phase, DNA Replication, and Chromosome organization (MRC) and was highly similar to the poor-prognosis mitosis-and-cell-cycle-module (MCM) in GBM. Assessment of gene expression in TCGA-derived GBMs revealed overexpression of MRC cancer genes AURKB, BIRC5, CCNB1, CCNB2, CDC2, CDK2, and FOXM1, which form a transcriptional network important for G2/M- progression and/or -checkpoint activation. In conclusion, our study supports propagation of GBM tumors as subcutaneous xenografts as a useful approach for sustaining key molecular characteristics of patient tumors, and highlights therapeutic opportunities conferred by this GBMX tumor panel for testing targeted therapeutic strategies for GBM treatment. Disease state analysis
Project description:Extrachromosomal DNA (ecDNA) are frequently observed in human cancers and are responsible for high levels of oncogene expression. In glioblastoma (GBM), ecDNA copy number correlates with poor prognosis. It is hypothesized that their copy number, size and chromatin accessibility facilitate clustering of ecDNA and colocalization with transcriptional hubs, and that this underpins their elevated transcriptional activity. Here, we use super-resolution imaging and quantitative image analysis to evaluate GBM stem cells harboring distinct ecDNA species (EGFR, CDK4, PDGFR). We found no evidence that ecDNA routinely cluster with one another or closely interact with transcriptional hubs. Cells with EGFR-containing ecDNA have increased EGFR transcriptional output, but transcription per gene copy was similar in ecDNA compared to the endogenous chromosomal locus. These data suggest that it is the increased copy number of oncogene-harboring ecDNA that primarily drives high levels of oncogene transcription, rather than specific interactions of ecDNA with each other or with high concentrations of the transcriptional machinery.
Project description:Characterization of gene expression for a panel of 50 in vitro and in vivo models of glioblastoma (GBM). Models include subcutaneously established xenograft lines, orthotopically grown subcutaneously established xenograft lines, serum derived cell lines and stem cell media derived cell lines. Multiple replicates of each line were run on different dates to determine the effect of batch and processing date on reproducibility of gene expression profiles 117 samples analyzed from 50 distinct GBM xenografts or cell lines. Biological replicates from the same passage number were included for many, but not all, of the lines.