Transcription profiling of human astrocytomas classified as low or high grade and glioma cell line controls (glioblastoma) to to identify genetic differences between the two types
Ontology highlight
ABSTRACT: Summary: Astrocytomas can be categorized as either low grade or high grade (glioblastoma). Low grade astrocytomas are not generally aggressive tumors whereas glioblastomas are and in turn have a high mortality rate. The purpose of this experiment is to identify genetic differences between the two types. Hypothesis: There will be a difference in RNA expression between high grade and low grade tumors. Specific Aim: To identify genes which make a tumor high grade or low grade Experiment Overall Design: Comparison of 8 high grade and 12 low grade tumors
Project description:Summary: Astrocytomas can be categorized as either low grade or high grade (glioblastoma). Low grade astrocytomas are not generally aggressive tumors whereas glioblastomas are and in turn have a high mortality rate. The purpose of this experiment is to identify genetic differences between the two types. Hypothesis: There will be a difference in RNA expression between high grade and low grade tumors. Specific Aim: To identify genes which make a tumor high grade or low grade Keywords: disease, cancer grade
Project description:Astrocytic tumors are known for their high progression capacity and for high mortality rates; in this regard, proteins correlated to prognosis can aid medical conduct. Although several genetic changes related to progression from low to high-grade astrocytoma are already known, mRNA copies do not necessarily correlate with protein abundance and, therefore could shadow further comprehension about this tumor’s biology. This motivates us to seek for complementary strategies to study tumor progression at the protein level. Here we compare the proteomic profile of biopsies from patients with low-grade (diffuse, n=6) versus high-grade astrocytoma (anaplastic and glioblastomas, n =10), using shotgun proteomics. Data analysis performed with PatternLab for proteomics identified 5,206 and 6,004 proteins in the low- and high-grade groups, respectively. Our results revealed seventy-four differentially abundant proteins (p < 0.01); we then shortlist those related to greater malignancy. We also describe molecular pathways distinctly activated in the two groups, such as differences in the organization of the extracellular matrix, decisive both in tumor invasiveness and in signaling for cell division, which, together with marked contrasts in energy metabolism, are determining factors in the speed of growth and dissemination of these neoplasms. The degradation pathways of GABA, enriched in the low-grade group, is consistent with a favorable prognosis. Other functions such as platelet degranulation, apoptosis, and activation of the MAPK pathway were correlated to high-grade tumors and, consequently, unfavorable prognoses. Our results provide an important survey of molecular pathways involved in glioma pathogenesis for these histopathological groups.
Project description:Astrocytomas are heterogeneous intracranial glial neoplasms ranging from the highly aggressive malignant glioblastoma multiforme (GBM) to the indolent, low-grade pilocytic astrocytoma. We have investigated whether DNA microarrays can identify gene expression differences between high-grade and low-grade glial tumors. We compared the transcriptional profile of 45 astrocytic tumors including 21 GBMs and 19 pilocytic astrocytomas using oligonucleotide-based microarrays. Of the approximately 6800 genes that were analyzed, a set of 360 genes provided a molecular signature that distinguished between GBMs and pilocytic astrocytomas. Many transcripts that were increased in GBM were not previously associated with gliomas and were found to encode proteins with properties that suggest their involvement in cell proliferation or cell migration. Microarray-based data for a subset of genes was validated using real-time quantitative reverse transcription-PCR. Immunohistochemical analysis also localized the protein products of specific genes of interest to the neoplastic cells of high-grade astrocytomas. Our study has identified a large number of novel genes with distinct expression patterns in high-grade and low-grade gliomas.
Project description:Astrocytomas are heterogeneous intracranial glial neoplasms ranging from the highly aggressive malignant glioblastoma multiforme (GBM) to the indolent, low-grade pilocytic astrocytoma. We have investigated whether DNA microarrays can identify gene expression differences between high-grade and low-grade glial tumors. We compared the transcriptional profile of 45 astrocytic tumors including 21 GBMs and 19 pilocytic astrocytomas using oligonucleotide-based microarrays. Of the approximately 6800 genes that were analyzed, a set of 360 genes provided a molecular signature that distinguished between GBMs and pilocytic astrocytomas. Many transcripts that were increased in GBM were not previously associated with gliomas and were found to encode proteins with properties that suggest their involvement in cell proliferation or cell migration. Microarray-based data for a subset of genes was validated using real-time quantitative reverse transcription-PCR. Immunohistochemical analysis also localized the protein products of specific genes of interest to the neoplastic cells of high-grade astrocytomas. Our study has identified a large number of novel genes with distinct expression patterns in high-grade and low-grade gliomas. hanas-00078 Assay Type: Gene Expression Provider: Affymetrix Array Designs: Hu6800 Organism: Homo sapiens (ncbitax) Tissue Sites: Brain Material Types: synthetic_DNA, synthetic_RNA, organism_part Disease States: Primary Glioma, Normal
Project description:Novel prognostic subclasses of high-grade astrocytoma are identified and discovered to resemble stages in neurogenesis. One tumor class displaying neuronal lineage markers shows longer survival, while two tumor classes enriched for neural stem cell markers display equally short survival. Poor prognosis subclasses exhibit either markers of proliferation or of angiogenesis and mesenchyme. Analysis of gene expression data is described in Phillips et al., Cancer Cell, 2006. Experiment Overall Design: 77 primary high-grade astrocytomas and 23 matched recurrences were profiled to identify changes in gene expression that relate to both survival and disease progression. Samples include WHO grade III and IV astrocytomas with a wide range of survival times.
Project description:Analysis of grades II, II and iV pediatric astrocytomas. Results used to straify tumors into molecular subclasses representative of adult tumors. The mesenchymal subtype is associated with high expression of immune response-related genes. Gene expression of grade II, III and IV pediatric astrocytomas, 24 individual tumor samples were profiled
Project description:Gene expression profiling in 50 glial brain tumors and 4 normal brains using 42,000-feature cDNA microarrays (from total RNA). Tumors: 50 fresh-frozen glioma specimens subjected to standard WHO classification. Specimens included astrocytic [2 juvenile pilocytic astrocytomas, 1 low-grade astrocytic glioma, 1 anaplastic astrocytomas, 31 glioblastomas (of these 2 secondary glioblastomas and 2 gliosarcomas)], oligodendroglial [5 oligodendrogliomas, 3 anaplastic oligodendrogliomas], and 6 anaplastic oligoastrocytomas tumors. One tumor had been classified as glioneuronal neoplasm. Normal brain was purchased from Stratagene. Stratagene Universal Common Reference was used as reference RNA. The results provide insights into molecular mechanisms and pathways associated with gliomagenesis.
Project description:Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Characterization of DNA copy number changes in 54 glial brain tumors using a cDNA microarray-based comparative genomic hybridization method. Tumors: 54 fresh-frozen glioma specimens subjected to standard WHO classification. Specimens included astrocytic [3 juvenile pilocytic astrocytomas, 1 low-grade astrocytic glioma, 3 anaplastic astrocytomas, 31 glioblastomas (of these 3 secondary glioblastomas and 2 gliosarcomas)], oligodendroglial [5 oligodendrogliomas, 3 anaplastic oligodendrogliomas], and 7 anaplastic oligoastrocytomas tumors. One tumor had been classified as glioneuronal neoplasm. Human male and female genomic reference DNA was purchased from Promega (Promega, Madison, WI). The results provide insights into molecular genetic changes associated with gliomagenesis.