Identification of genes involved in SHH subgroup medulloblastoma using murine whole-body Sleeping Beauty insertional mutagenesis
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ABSTRACT: Ptch+/- mice, which are predisposed to SHH subgroup medulloblastoma, were mutagenised using the Sleeping Beauty transposon to identify genes which increase the frequency of medulloblastoma formation. Gene expression in tumours was assessed both to investigate their relationship to human subgroup tumours, and to identify genes where expression was altered by mutagenesis. Total RNA isolated from tumours induced by SB mutagenesis were compared to normal cerebellum, tumours induced witout SB mutagenesis, and tumours from a distinct model of disease (GTML).
Project description:Ptch+/- mice, which are predisposed to SHH subgroup medulloblastoma, were mutagenised using the Sleeping Beauty transposon to identify genes which increase the frequency of medulloblastoma formation. Gene expression in tumours was assessed both to investigate their relationship to human subgroup tumours, and to identify genes where expression was altered by mutagenesis.
Project description:Nude mice were allografted with medulloblastoma tumors derived from Ptch+/-HIC+/- transgenic mouse and treated with vehicle or NVP-LDE225. RNA was prepared from tumours from vehicle or NVP-LDE225 treated nude mice allografted with medulloblastoma tumors derived from Ptch+/-HIC+/- transgenic mouse and hybridized on the Affymetrix Mouse Genome 430A 2.0 RNA expression microarray.
Project description:Nude mice were allografted with medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse and treated with vehicle or NVP-LDE225. RNA was prepared from tumours from vehicle or NVP-LDE225 treated nude mice allografted with medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse and hybridized on the Affymetrix Mouse Genome 430A 2.0 RNA expression microarray.
Project description:A Sleeping Beauty (SB) transposon forward genetic screen was performed to identify the genes that promote osteosarcoma (OS) development and metastasis. Mutagenesis induced OS in wild type mice and accelerated it on a Trp53 deficient background. Analysis of tumors demonstrated that Trp53 deficiency is correlated with genomic instability, which was virtually absent in tumors induced by SB mutagenesis alone. Metastases developed in a subset of animals and in nearly all cases were clonal related to primary tumors. Over 200 candidate genes were identified, many of which are altered in human cancers including OS. Signaling pathways enriched for candidate genes were also identified and a subset of these pathways and genes were functionally validated and represent new targets for OS treatment.
Project description:Medulloblastoma is a malignant childhood brain tumour comprising four discrete subgroups. To identify mutations that drive medulloblastoma we sequenced the entire genomes of 37 tumours and matched normal blood. One hundred and thirty-six genes harbouring somatic mutations in this discovery set were sequenced in an additional 56 medulloblastomas. Recurrent mutations were detected in 41 genes not yet implicated in medulloblastoma: several target distinct components of the epigenetic machinery in different disease subgroups, e.g., regulators of H3K27 and H3K4 trimethylation in subgroup-3 and 4 (e.g., KDM6A and ZMYM3), and CTNNB1-associated chromatin remodellers in WNT-subgroup tumours (e.g., SMARCA4 and CREBBP). Modelling of mutations in mouse lower rhombic lip progenitors that generate WNT-subgroup tumours, identified genes that maintain this cell lineage (DDX3X) as well as mutated genes that initiate (CDH1) or cooperate (PIK3CA) in tumourigenesis. These data provide important new insights into the pathogenesis of medulloblastoma subgroups and highlight targets for therapeutic development. A total of 76 pediatric medulloblastoma samples were analyzed, representing 4 expression classes
Project description:To identify genes important for colorectal cancer (CRC) development and metastasis, we established a new metastatic mouse organoid model using Sleeping Beauty (SB) transposon mutagenesis. Intestinal organoids derived from mice carrying actively mobilizing SB transposons, an activating KrasG12D, and an inactivating ApcΔ716 allele, were transplanted to immunodeficient mice. Analysis of SB insertion sites in tumors identified numerous candidate cancer genes (CCGs) identified previously in intestinal SB screens performed in vivo, in addition to new CCGs, such as Atxn1. To provide functional validation, we knocked out Atxn1 in mouse tumor organoids carrying an activating KrasG12D, and an inactivating ApcΔ716 allele, and transplanted to mice. Tumor development was promoted when these gene were knocked out, demonstrating that these are potent tumor suppressors.
Project description:A Sleeping Beauty (SB) transposon forward genetic screen was performed to identify the genes that promote osteosarcoma (OS) development and metastasis. Mutagenesis induced OS in wild type mice and accelerated it on a Trp53 deficient background. Analysis of tumors demonstrated that Trp53 deficiency is correlated with genomic instability, which was virtually absent in tumors induced by SB mutagenesis alone. Metastases developed in a subset of animals and in nearly all cases were clonal related to primary tumors. Over 200 candidate genes were identified, many of which are altered in human cancers including OS. Signaling pathways enriched for candidate genes were also identified and a subset of these pathways and genes were functionally validated and represent new targets for OS treatment. Bisulphite converted DNA from the 21 diagnosis osteosarcoma patients and 3 hOB cell line replicates were hybridised to the Illumina Infinium 450K Human Methylation Beadchip.
Project description:Medulloblastoma is a malignant childhood brain tumour comprising four discrete subgroups. To identify mutations that drive medulloblastoma we sequenced the entire genomes of 37 tumours and matched normal blood. One hundred and thirty-six genes harbouring somatic mutations in this discovery set were sequenced in an additional 56 medulloblastomas. Recurrent mutations were detected in 41 genes not yet implicated in medulloblastoma: several target distinct components of the epigenetic machinery in different disease subgroups, e.g., regulators of H3K27 and H3K4 trimethylation in subgroup-3 and 4 (e.g., KDM6A and ZMYM3), and CTNNB1-associated chromatin remodellers in WNT-subgroup tumours (e.g., SMARCA4 and CREBBP). Modelling of mutations in mouse lower rhombic lip progenitors that generate WNT-subgroup tumours, identified genes that maintain this cell lineage (DDX3X) as well as mutated genes that initiate (CDH1) or cooperate (PIK3CA) in tumourigenesis. These data provide important new insights into the pathogenesis of medulloblastoma subgroups and highlight targets for therapeutic development.
Project description:This SuperSeries is composed of the following subset Series: GSE22005: Medulloblastoma tumors derived from Ptch+/-HIC+/- transgenic mouse allografted in nude mice GSE22006: Medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse allografted in nude mice Refer to individual Series
Project description:Mutations in Hedgehog (Hh) pathway genes, leading to constitutive activation of Smoothened (Smo), occur in sporadic medulloblastoma, the most common brain cancer in children. Antagonists of Smo induce tumor regression in mouse models of medulloblastoma and hold great promise for targeted therapy for this tumor. However, acquired resistance has emerged as one of the major challenges of targeted cancer therapy. Here, we describe novel mechanisms of acquired resistance to Smo antagonists in medulloblastoma. NVP-LDE225, a potent and selective Smo antagonist, inhibits Hh signaling and induces tumor regressions in allograft models of medulloblastoma that are driven by mutations of Patched (Ptch), a tumor suppressor in the Hh pathway. However, after long-term treatment, evidence of acquired resistance was observed. Genome-wide profiling of resistant tumors revealed distinct mechanisms to evade the inhibitory effects of Smo antagonists. Chromosomal amplification of Gli2, a downstream effector of Hh signaling, reactivated Hh signaling and restored tumor growth. Analysis of pathway gene-expression signatures selectively deregulated in resistant tumors identified increased phosphoinosite-3-kinase (PI3K) signaling as another potential resistance mechanism. Probing the functional relevance of increased PI3K signaling, we showed that the combination of NVP-LDE225 with the dual PI3K/mTOR inhibitor NVP-BEZ235 markedly delayed the development of resistance. Our findings have important clinical implications for future treatment strategies in medulloblastoma. mRNA profiling: RNA was prepared from tumours from vehicle or NVP-LDE225 treated nude mice allografted with medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse and hybridized on Affymetrix Mouse Genome 430 2.0 RNA expression array. The dosage terminology (BID & QD) reflects the dosing schedule, where BID = twice a day, QD = once a day. aCGH: DNA was prepared from tumors from vehicle or NVP-LDE225 treated nude mice allografted with medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse and hybridized on Agilent mouse CGH 244K Array.