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Hierarchical synergy of Pten, p53 and Rb pathways in high-grade astrocytoma induced in adult brain

ABSTRACT: Mutations in the PTEN, TP53 and RB1 pathways are obligate events in the pathogenesis of human glioblastomas, the highest grade of astrocytoma. To investigate synergy between these tumor suppressors in mice, we induced various combinations of compound deletions conditionally in astrocytes and neural precursors in the mature brain. The resulting highly penetrant astrocytomas showed a spectrum of histopathological variation reminiscent of human tumors, and ranged from grade III to grade IV (glioblastoma). Secondary somatic mutations varied depending on the combination of initiating deletions and were relevant to human disease. Receptor tyrosine kinase amplifications were frequent in tumors initiated by combined conditional deletion of Pten and Tp53, but not when Rb, Pten and Tp53 were simultaneously deleted. Multiple mutations within PI3K and Rb pathways were acquired, however, Mapk activation was not consistently detected in astrocytomas. Gene expression profiling revealed striking similarities to previously described human astrocytoma subclasses. A subset of astrocytomas initiated outside of proliferative niches in the adult brain.

ORGANISM(S): Mus musculus Homo sapiens

PROVIDER: GSE22927 | GEO | 2011/03/23

SECONDARY ACCESSION(S): PRJNA127619

REPOSITORIES: GEO

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Hierarchical synergy of Pten, p53 and Rb pathways in high-grade astrocytoma induced in adult brain

Project description:Mutations in the PTEN, TP53 and RB1 pathways are obligate events in the pathogenesis of human glioblastomas, the highest grade of astrocytoma. To investigate synergy between these tumor suppressors in mice, we induced various combinations of compound deletions conditionally in astrocytes and neural precursors in the mature brain. The resulting highly penetrant astrocytomas showed a spectrum of histopathological variation reminiscent of human tumors, and ranged from grade III to grade IV (glioblastoma). Secondary somatic mutations varied depending on the combination of initiating deletions and were relevant to human disease. Receptor tyrosine kinase amplifications were frequent in tumors initiated by combined conditional deletion of Pten and Tp53, but not when Rb, Pten and Tp53 were simultaneously deleted. Multiple mutations within PI3K and Rb pathways were acquired, however, Mapk activation was not consistently detected in astrocytomas. Gene expression profiling revealed striking similarities to previously described human astrocytoma subclasses. A subset of astrocytomas initiated outside of proliferative niches in the adult brain. Gene expression of 8 human brain samples including 2 normal brainstem and 6 brainstem low-grade gliomas were profiled using HG-U133 plus 2 arrays. Gene expression of 38 mouse tumor samples, including 24 Pten;p53 double knockout and 14 Pten;p53;Rb1 triple knockout, were profiled using Affymetrix Mouse Genome 430 v2 arrays. Copy number changes of 51 double knockout tumor samples were analysed using Roswell Park Cancer Institute 6.5k BAC arrays. Copy number changes of 21 triple knockout tumor samples were analysed using Agilent mouse genome CGH mocirarray 244A.

2011-03-23 | E-GEOD-22927 | biostudies-arrayexpress

Inducible Astrocytomas in Genetically Engineered Mice: Affymetrix

Project description:To determine the regulatory pathways necessary for astrocytoma formation within complex adult brain microenvironments, we engineered mice for adult astrocyte-specific disruption of key regulators (pRb, Kras and Pten). Drivers of all astrocytoma grades were identified using CreERTM-inducible alleles. Inactivation of pRb was necessary to initiate grade II disease, and was the only lesion to do so. Additional activation of Kras progressed disease to grade III, while further Pten inactivation facilitated grade IV (glioblastoma) progression. These outcomes were elicited whether somatic events were induced broadly or focally. In vivo inactivation of pRb, which induced astrocyte proliferation and apoptosis, activated the MAPK pathway, while Kras activation and Pten loss triggered PI3K pathways. TRPhet denotes mice with Inhibition of Rb, Over-expression of Kras and Deletion of one Copy of PTEN; TRPnull denotes mice with Inhibition of Rb, Over-expression of Kras and Deletion of both copies of PTEN; TR denotes mice with Inhibition of Rb, Over-expression of Kras.

2012-09-13 | GSE26002 | GEO

Inducible Astrocytomas in Genetically Engineered Mice: Agilent

2012-09-13 | GSE26068 | GEO

Affymetrix SNP array data for low-grade astrocytoma samples

Project description:Copy number analysis of 21 paediatric low-grade astrocytomas identified a discrete copy number gain of 1.9Mb in chromosome band 7q34. The gain was present in 12/14 cerebellar pilocytic astrocytomas. Subsequent analysis of tumour cDNA indentified a novel gene fusion between KIAA1549 and BRAF in these tumours. Copy number analysis of 21 paediatric low-grade astrocytomas using the Affymetrix GeneChip Human Mapping 250K Nsp Array. This study comprised 14 pilocytic astrocytomas, 4 diffuse astrocytomas, one pilomyxoid astrocytoma, one pilomyxoid glioma and one pleomorphic xanthoastrocytoma. Tumours were compared to the mean of two normal male DNA controls.

2010-04-09 | E-GEOD-14960 | biostudies-arrayexpress

Astrocytoma cell lines transduced to either express GFAP isoforms or to knockdown GFAP isoforms

Project description:Modulation of the GFAP cytoskeleton in astrocytoma cells alters processes involved in extracellular matrix remodelling and cell-cell signalling – a transcriptome analysis Astrocytomas grade IV are malignant brain tumours with no effective treatment and a five year survival rate of only 5%. Expression of Glial Fibrillary Acidic Protein (GFAP) is lower in high astrocytoma grade, but the expression of the splice isoform GFAPδ is similar in low and high-grade astrocytomas. Thus the ratio of GFAPδ/α is increased in high-grade astrocytomas. We studied transcriptome changes in astrocytoma cell lines resulting from an induced alteration of GFAP isoform expression. GFAPα or GFAPδ were increased or decreased by recombinant expression or shRNA mediated knockdown of GFAPpan or GFAPα. We find that the most prominent effects are induced by the modulations where the GFAPδ/GFAPα ratio is increased. Gene ontology analysis revealed that the main effects of GFAP modulation take place in the extracellular matrix remodelling and cellular signalling clusters, with possible implications in astrocytoma invasive behaviour and angiogenesis.

2017-07-03 | GSE74567 | GEO

Mouse high grade astrocytoma cells (GL261) treated with neural stem/precursor cell (NPC) conditioned medium or non-conditioned medium (control)

Project description:Primary astrocytomas of high histopathological grade (HG-astrocytomas) are largely restricted to older patients and are almost invariably fatal despite multimodal therapy. Here, we show that the young brain has an endogenous defense mechanisms against HG-astrocytomas. Neural precursor cells (NPCs) migrate to HG-astrocytomas, reduce glioma expansion and prolong survival by releasing a group of fatty-acid ethanolamides that have agonistic activity on the vanilloid receptor (transient receptor potential vanilloid subfamily member-1; TRPV1). TRPV1 expression is much higher in HG-astrocytomas than in the tumor-free brain and TRPV1 stimulation triggers tumor cell-death via the activating transcription factor-3 (ATF3) controlled branch of the ER-stress pathway. The anti-tumourigenic response of NPCs is lost with aging. NPC-mediated tumor suppression can be mimicked in the old brain by systemic administration of the synthetic vanilloid Arvanil, indicating that TRPV1 agonists hold potential as new HG-astrocytoma therapeutics. The goal of this microarray study was understand how neural stem / precursor cell (NPC) induced high grade astrocytoma cell-death is controlled by changes in gene expression. We investigated the gene-expression pattern in mouse high grade astrocytoma GL261 cells after incubation with NPC non-conditioned medium (controls) or NPC-conditioned medium by microarrays and found that endoplasmic reticulum stress genes like the activating transcription factor-3 (ATF3) were robustly up-regulated in NPC-conditioned medium treated mouse high grade astrocytoma cells, compared to controls. Comparison of two experimental groups (conditioned medium treated versus non-conditioned medium treated) in three dye swap experiments (6 arrays used in total).

2012-04-30 | E-GEOD-37671 | biostudies-arrayexpress

Transcription profiling of human high-grade astrocytomas reveals prognostic subgroups

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.

2007-10-02 | E-GEOD-4271 | biostudies-arrayexpress

caArray_hanas-00078: Distinctive molecular profiles of high-grade and low-grade gliomas based on oligonucleotide microarray analysis

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.

2015-06-25 | GSE70231 | GEO

TMPRSS2-ERG suppresses PTEN/TP53 alteration-induced cancer lineage plasticity

Project description:Lineage plasticity is a major mechanism driving prostate cancer progression and antiandrogen therapy resistance. Deletions or mutations in phosphatase and tensin homolog (PTEN) and TP53 tumor suppressor genes have been linked to lineage plasticity in prostate cancer. Fusion-driven overexpression of the E-twenty-six transformation specific (ETS)-related gene (ERG), encoding an oncogenic transcription factor, is observed in approximately 50% of all prostate cancers, yet its role in prostate cell lineage determination remains elusive. Here we demonstrate that transgenic expression of prostate cancer-associated ERG blocks Pten and Trp53 mutation-induced decreased expression of Ar and its downstream target genes and loss of luminal epithelial cell identity in the mouse prostate. Integrative analyses of ERG chromatin-immunoprecipitation sequencing (ChIP-seq) and transcriptome data show that ERG suppresses expression of a subset of cell cycle-promoting genes and RB phosphorylation, which in turn causes repression of E2F1-mediated expression of non-epithelial lineage genes. Xenograft studies show that PTEN/TP53 double mutated prostate tumors are responsive to the cyclin-dependent kinase 4 or 6 (CDK4/6) inhibitor palbociclib, but resistant to the AR inhibitor enzalutamide, while ERG/PTEN/TP53 triple-mutated prostate tumors behave completely opposite. Our studies identify ERG and the repressed cell cycle gene signature as intrinsic inhibitors of PTEN/TP53 double mutation-elicited lineage plasticity in prostate cancer. Our findings also suggest that ERG fusion can be utilized as a biomarker to guide the treatment of PTEN/TP53-mutated, RB1-intact prostate cancer with either antiandrogen or anti-CDK4/6 therapies.

2018-05-16 | GSE103871 | GEO

caArray_hanas-00078: Distinctive molecular profiles of high-grade and low-grade gliomas based on oligonucleotide microarray analysis

2015-06-25 | E-GEOD-70231 | biostudies-arrayexpress

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