Project description:Medulloblastoma is the most common pediatric CNS cancer. In order to identify important molecules important for deregulated tumor cell growth, we use microarray to detail the global gene expression profile in Shh-driven mouse medulloblastomas and determine the most differentially expressed genes compared to the control wild-type cerebellum.
Project description:Medulloblastoma is the most common pediatric CNS cancer. In order to identify important molecules important for deregulated tumor cell growth, we use microarray to detail the global gene expression profile in Shh-driven mouse medulloblastomas and determine the most differentially expressed genes compared to the control wild-type cerebellum. Medulloblastoma and control cerebellum tissues were dissected and processed for RNA extraction and microarray analyses using Affymetrix Mouse Gene 1.0 ST. The mice were from a mixed genetic background involving C57BL/6 and C3H strains.
Project description:Primary glioblastoma, representing over 90% of adult glioblastoma, develop rapidly without preexisting lower-grade glioma. We have generated a mouse model of primary glioblastoma driven by a single p53 mutation. These p53-mutant gliomas lose the syntenic region of human chromosome 10q, which is mapped to mouse chr19 and chr7. Loss of mouse chr19, containing Pten, activates PI3K/Akt signaling. Rictor/mTORC2 deletion inhibits Akt signaling, causing a significant delay in p53-mutant driven glioma formation. Unexpectedly, Rictor/mTORC2 loss promotes p53-mutant driven medulloblastomas with unique features of pediatric SHH medulloblastoma. Mechanistically, Rictor/mTORC2 loss inhibits the generation of glioma precursor cells from neural stem/progenitor cells in the adult brain, while causing a delay in differentiation of granule cell precursors in the developing brain, a cell-of-origin of SHH medulloblastoma.
Project description:Medulloblastoma, the most common malignant pediatric brain tumor, is highly heterogeneous with distinct molecular subtypes and cellular origins. Although current treatments improve survival rates, patients suffer severe treatment-related side effects and often relapse of tumors carrying resistance mutations, underscoring an urgent need for alternative targeted therapies. Currently, the genetic alterations underlying this disease are not fully understood. Here we identify GNAS, encoding the G-protein Gs-alpha, as a potent tumor suppressor gene in medulloblastoma. GNAS specifically defines a subset of aggressive Sonic Hedgehog (Shh)-group medulloblastomas. Gnas loss-of-function in distinct lineage progenitors of the developing hindbrain suffices to initiate medulloblastoma. We find that Gs-alpha is highly enriched at primary cilia of granule neuron precursors and suppresses Shh signaling not only by regulating classic cAMP-dependent pathway but also controlling ciliary trafficking of Smoothened. Concurrent cAMP elevation and Smoothened inhibition robustly arrests tumor cell growth in Gnas mutants. We further reveal oligodendrocyte progenitors as a novel cellular origin for anatomically-distinct Shh-associated medulloblastomas. Together, we identify a previously unrecognized tumor suppressor function of Gs-alpha in medulloblastoma partially mediated through inhibiting Shh signaling, and uncover Gs-alpha as a molecular link across disparate cells of origin among Shh-group medulloblastomas, pointing to G- protein modulation as a potential therapeutic avenue. Purpose: To known the gene expression profile of Medulloblastoma which drived by Gnas mutation Methods: mRNAs isolated from the cerebellum of control and Gnas mutants Results:Upregulation of Shh Signaling components in tumors Conclusions: The deletion of Gnas in hGFAP and Olig1 possitive cells result in substantial upregulation of shh signaling and formation of Medulloblastoma cerebellum mRNA profiles of 3 60-day old wild type (Ctrl) and 8 Olig1Cre driven Gsa conditional knockout or 8 hGFAPCre driven conditional knockout mice were generated by deep sequencing using Illumina Hiseq2000
Project description:The childhood brain tumour medulloblastoma includes four subtypes with very different prognoses. Here, we show that paracrine signals driven by mutant Beta-Catenin in WNT-medulloblastoma â an essentially curable form of the disease â induce an aberrant fenestrated vasculature that permits the accumulation of high levels of intra-tumoural chemotherapy and a robust therapeutic response. In contrast, SHH-medulloblastoma â a less curable disease subtype â contains an intact blood brain barrier, rendering this tumour impermeable and resistant to chemotherapy. Remarkably, the medulloblastoma-endothelial cell paracrine axis can be manipulated in vivo, altering chemotherapy permeability and clinical response. Thus, medulloblastoma genotype dictates tumour vessel phenotype, explaining in part the disparate prognoses among medulloblastoma subtypes and suggesting an approach to enhance the chemoresponsiveness of other brain tumours. We used microarrays to detail the global program of gene expression within endothelial cells from normal mouse hindbrain and genetic mouse models of different medulloblastoma subtypes to identify and verify up-regulated and down-regulated genes Endothelial cells were isolated from adult mouse hindbrain and genetic mouse models of Wnt and Shh-medulloblastoma using Cd-144 and Cd-105 antibodies based magnetic sorting. RNA was extracted and used for hybridization on Affymetrix microarrays. We sought to identify changes in endothelial gene expression patterns based on the surrounding microenvironment, so we purified endothelial cells from normal mouse brain or tumors from genetic mouse models. These include the Shh-medulloblastoma model (Ptch+/-; Ink4c -/-) and Wnt-medulloblastoma model (Blbp-Cre; mutant Ctnnb1+/-; p53-/-; mutant Pik3ca +/-)
Project description:The Ptch1+/- strain constitues an established mouse model for the Shh-driven type of medulloblastoma. Combined Ptch1+/- Nos2-/- mice show a two-fold increased incidence for this tumor. Here, the impact of Nos2 inactivation on copy number alterations during medulloblastoma development was investigated by array-based comparative genomic hybridization (arrayCGH) of tumor samples from both genotypes. Medulloblastoma samples from five Ptch1+/- and seven compound Ptch1+/- Nos2-/- mice were analyzed. Cy5-labeled tumor DNA was combined with corresponding Cy3-labeled reference healthy wildtype genomic DNA to receive either sex-matched sample pairs or pairs of different gender for internal negative or positive control.
Project description:Here we present the case of adult medulloblastoma with minimal chromosomal rearrangements but Shh expression profile and IDH1 mutation. Data presented here are NanoString analyses of two biopsies of adult patient with a medulloblastoma which was classified as a Shh subtype
Project description:Here we present the case of adult medulloblastoma with minimal chromosomal rearrangements but Shh expression profile and IDH1 mutation. Data presented here are NanoString analyses of two biopsies of adult patient with a medulloblastoma which was classified as a Shh subtype Analyses were performed on 2 archival specimens of medulloblastoma, WHO Grade IV, seen at the Department of Pathology, Massachusetts General Hospital in 2007.
Project description:The Ptch1+/- strain constitues an established mouse model for the Shh-driven type of medulloblastoma. Combined Ptch1+/- Nos2-/- mice show a two-fold increased incidence for this tumor. Here, the impact of Nos2 inactivation on copy number alterations during medulloblastoma development was investigated by array-based comparative genomic hybridization (arrayCGH) of tumor samples from both genotypes.
Project description:The Ptch1+/- strain constitues an established mouse model for the Shh-driven type of medulloblastoma. Combined Ptch1+/- Nos2-/- mice show a two-fold increased incidence for this tumor. Here, the impact of Nos2 inactivation on medulloblastoma development was investigated by gene expression profiling of tumor samples as well as healthy cerebellum at different ages and genotypes.