CNS methylation classifiers may misclassify normal developing cerebellar cortex as medulloblastoma.
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ABSTRACT:
PROVIDER: PRJNA1274024 | ENA |
REPOSITORIES: ENA
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Project description:DNA methylation profiling is commonly utilized in tumor diagnosis and has shown diagnostic specificity in many contexts. We recently noted that several CNS tumor classifiers used for neuropathology clinical diagnostics fail to appropriately classify pediatric cerebellar cortex tissue as non-neoplastic. Our study illustrates a gap in classifier accuracy that is most evident with samples from very young patients (<6 months). In this setting,classifiers typically assign medulloblastoma, SHH-activated, and occasionally show high-confidence scores. Neuropathologists practicing in pediatric settings should be aware of the histologic appearance of immature cerebellar tissue, and exercise caution when performing methylation profiling of samples of uncertain neoplastic status for patients in early infancy.
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Project description:Origins of the brain tumor, medulloblastoma, from stem cells or restricted pro-genitor cells are unclear. To investigate this, we activated oncogenic Hedgehog signaling in multipotent and lineage-restricted CNS progenitors. We observed that normal unipo-tent cerebellar granule neuron precursors (CGNP) derive from hGFAP+ and Olig2+ rhombic lip progenitors. Hedgehog activation in a spectrum of early and late stage CNS progenitors generated similar medulloblastomas, but not other brain cancers, indicating that acquisition of CGNP identity is essential for tumorigenesis. We show in human and mouse medulloblastoma that cells expressing the glia-associated markers Gfap and Olig2 are neoplastic and that they retain features of embryonic-type granule lineage progenitors. Thus, oncogenic Hedgehog signaling promotes medulloblastoma from lineage-restricted granule cell progenitors. Gene expression profiling of cerebellar tumors generated from various early and late stage CNS progenitor cells. Experiment Overall Design: Group comparisons with biological replicates
2008-10-21 | E-GEOD-11859 | biostudies-arrayexpress
Project description:Origins of the brain tumor, medulloblastoma, from stem cells or restricted pro-genitor cells are unclear. To investigate this, we activated oncogenic Hedgehog signaling in multipotent and lineage-restricted CNS progenitors. We observed that normal unipo-tent cerebellar granule neuron precursors (CGNP) derive from hGFAP+ and Olig2+ rhombic lip progenitors. Hedgehog activation in a spectrum of early and late stage CNS progenitors generated similar medulloblastomas, but not other brain cancers, indicating that acquisition of CGNP identity is essential for tumorigenesis. We show in human and mouse medulloblastoma that cells expressing the glia-associated markers Gfap and Olig2 are neoplastic and that they retain features of embryonic-type granule lineage progenitors. Thus, oncogenic Hedgehog signaling promotes medulloblastoma from lineage-restricted granule cell progenitors. Gene expression profiling of cerebellar tumors generated from various early and late stage CNS progenitor cells.
2008-06-24 | GSE11859 | GEO
Project description:Deregulated developmental processes in the cerebellum cause medulloblastoma, the most common malignant tumor of the central nervous system. About 20-30% of cases are caused by mutations increasing the activity of the Sonic hedgehog (Shh) pathway, a critical mitogen in cerebellar development. The proto-oncogene Smoothened is a key transducer of the Shh pathway. Activating mutations in Smoothened that lead to constitutive activity of the Shh pathway have been identified in human medulloblastoma. To understand the molecular and cellular effects of Smoothened variants in normal development and medulloblastoma genesis, we generated the SmoA2 transgenic mouse model which expresses the transgene exclusively in granule neuron precursors. In this study, we demonstrate how two point mutations in a single molecule can produce starkly different phenotypes as seen in comparison to our previous model, ND2:SmoA1. The SmoA2 mice have severe aberrations in cerebellar development whereas the SmoA1 mice are largely normal during development. Medulloblastomas in the SmoA2 mice develop in the dysplastic cerebellar milieu. Intriguingly, despite disruptions in the stereotypic organization of the cerebellum, the SmoA2 mice do not exhibit any overt abnormalities in motor coordination. The differences in the global transcriptional profiles downstream of SmoA1 and SmoA2 further demonstrate the distinctiveness of the two oncogenic Smoothened mutations. The SmoA2 model serves as a unique spatiotemporal tool to investigate the functional significance of the reiterative cerebellar circuitry as well as to further understand Shh pathway mechanics in cerebellar development and oncogenesis. We previously generated a SmoA1 transgenic mouse medulloblastoma model, which expresses the SmoA1 transgene driven by the GNP-specific fragment of the promoter of ND2 transcription factor leading to constitutively active Shh signaling exclusively in the cerebellum. In this study, we characterize the ND2:SmoA2 transgenic mouse model with a similarly designed transgene expressing the SmoA2 mutation. To assess transcriptional changes downstream of SmoA1 and SmoA2, we evaluated global gene expression profiles of P5 SmoA1, SmoA2 and Wt age-matched cerebella. We chose this specific developmental stage because (1) the phenotypes of SmoA1 and SmoA2 are robust and distinct at P5; (2) at P5 GNPs undergo proliferation, migration and differentiation and therefore expression profiling could capture key differences in multiple processes.
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Project description:Deregulated developmental processes in the cerebellum cause medulloblastoma, the most common malignant tumor of the central nervous system. About 20-30% of cases are caused by mutations increasing the activity of the Sonic hedgehog (Shh) pathway, a critical mitogen in cerebellar development. The proto-oncogene Smoothened is a key transducer of the Shh pathway. Activating mutations in Smoothened that lead to constitutive activity of the Shh pathway have been identified in human medulloblastoma. To understand the molecular and cellular effects of Smoothened variants in normal development and medulloblastoma genesis, we generated the SmoA2 transgenic mouse model which expresses the transgene exclusively in granule neuron precursors. In this study, we demonstrate how two point mutations in a single molecule can produce starkly different phenotypes as seen in comparison to our previous model, ND2:SmoA1. The SmoA2 mice have severe aberrations in cerebellar development whereas the SmoA1 mice are largely normal during development. Medulloblastomas in the SmoA2 mice develop in the dysplastic cerebellar milieu. Intriguingly, despite disruptions in the stereotypic organization of the cerebellum, the SmoA2 mice do not exhibit any overt abnormalities in motor coordination. The differences in the global transcriptional profiles downstream of SmoA1 and SmoA2 further demonstrate the distinctiveness of the two oncogenic Smoothened mutations. The SmoA2 model serves as a unique spatiotemporal tool to investigate the functional significance of the reiterative cerebellar circuitry as well as to further understand Shh pathway mechanics in cerebellar development and oncogenesis.
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Project description:Germline loss-of-function (LOF) variants in Elongator complex protein 1 (ELP1) are the most prevalent predisposing genetic events in childhood medulloblastoma (MB), accounting for ~30% of the Sonic Hedgehog (SHH) 3 subtype. The underlying mechanism(s) by which germline ELP1 deficiency provokes SHH-MB pathogenesis remain unknown. Genetically engineered mice mimicking heterozygous germline Elp1 LOF (Elp1HET) seen in affected germline carriers exhibit hallmark features of cancer predisposition in cerebellar granule neuron progenitors (GNPs), including increased DNA replication stress, genomic instability, accelerated cell cycle, and stalled differentiation. Orthotopic transplantation of Elp1HET GNPs harboring somatic Ptch1 inactivation yielded SHH-MB-like tumors with compromised p53 signaling, providing an explanation for the exclusivity of ELP1-associated MBs in SHH-3 subtype. Preclinical treatment of ELP1-mutant patient-derived xenografts with an FDA-approved HDM2 inhibitor reactivated p53-dependent apoptosis and extended survival. Our findings functionally substantiate the role of ELP1 deficiency in SHH-MB predisposition and nominate therapeutics that overcome p53 inhibition as a rational treatment option.
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Project description:Germline loss-of-function (LOF) variants in Elongator complex protein 1 (ELP1) are the most prevalent predisposing genetic events in childhood medulloblastoma (MB), accounting for ~30% of the Sonic Hedgehog (SHH) 3 subtype. The underlying mechanism(s) by which germline ELP1 deficiency provokes SHH-MB pathogenesis remain unknown. Genetically engineered mice mimicking heterozygous germline Elp1 LOF (Elp1HET) seen in affected germline carriers exhibit hallmark features of cancer predisposition in cerebellar granule neuron progenitors (GNPs), including increased DNA replication stress, genomic instability, accelerated cell cycle, and stalled differentiation. Orthotopic transplantation of Elp1HET GNPs harboring somatic Ptch1 inactivation yielded SHH-MB-like tumors with compromised p53 signaling, providing an explanation for the exclusivity of ELP1-associated MBs in SHH-3 subtype. Preclinical treatment of ELP1-mutant patient-derived xenografts with an FDA-approved HDM2 inhibitor reactivated p53-dependent apoptosis and extended survival. Our findings functionally substantiate the role of ELP1 deficiency in SHH-MB predisposition and nominate therapeutics that overcome p53 inhibition as a rational treatment option.
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Project description:This study explores the role of Ezh2 in delaying the activation of differentiation genes during the development of cerebellar granule neurons (GNPs) and in SHH subtype medulloblastoma. To investigate the epigenetic landscape, we performed chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) on GNPs and medulloblastoma cells derived from Ptch1 heterozygous mice. We profiled histone modifications and key regulatory proteins, including H3K27me3, H3K27ac, H3K36me3, H3K4me3, H3K4me1, H2Aubi119, Ring1b, and Pol2S5. Additionally, we conducted ATAC-seq to assess chromatin accessibility and MIRA-seq to study DNA methylation. This dataset aims to compare the epigenetic state of normal granule neuron progenitors with that of medulloblastoma cells, providing insight into how epigenetic mechanisms contribute to neuronal differentiation. We found that the inhibition of Ezh2-mediated H3K27 methylation represses differentiation in both GNPs and medulloblastoma cells.
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Project description:This study explores the role of Ezh2 in delaying the activation of differentiation genes during the development of cerebellar granule neurons (GNPs) and in SHH subtype medulloblastoma. To investigate the epigenetic landscape, we performed chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) on GNPs and medulloblastoma cells derived from Ptch1 heterozygous mice. We profiled histone modifications and key regulatory proteins, including H3K27me3, H3K27ac, H3K36me3, H3K4me3, H3K4me1, H2Aubi119, Ring1b, and Pol2S5. Additionally, we conducted ATAC-seq to assess chromatin accessibility and MIRA-seq to study DNA methylation. This dataset aims to compare the epigenetic state of normal granule neuron progenitors with that of medulloblastoma cells, providing insight into how epigenetic mechanisms contribute to neuronal differentiation. We found that the inhibition of Ezh2-mediated H3K27 methylation represses differentiation in both GNPs and medulloblastoma cells.
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