6878a39e-68bf-4c95-9a24-1a416bc8dabc - samples
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ABSTRACT:
PROVIDER: EGAD00001006045 | EGA |
REPOSITORIES: EGA
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Project description:Posterior fossa molecular subtype A (PFA) ependymoma occurs in young children and is the deadliest subtype of pediatric ependymoma. High-risk subtypes with chromosome 1q+ and/or 6q- exhibit significantly poorer outcome compared to wild-type PFA. However, 50% of wild-type PFA patients relapse and there is a high risk of gaining chromosome 1q at recurrence. We previously found constitutively active NF-kB, through loss of LDOC1, led to chronic IL-6 secretion and an overall immunosuppressive tumor microenvironment in the higher risk wild-type PFA ependymoma subset (PFA1). In this study, we delineate the mechanistic consequences of LDOC1 loss in PFA1, using our PFA ependymoma in vitro and in vivo models under normoxia and hypoxia conditions. We noted chromatin compaction by H3K27me3 at the LDOC1 loci results in loss of LDOC1 gene expression. Restoration of LDOC1 was sufficient to reduce proliferation, NF-kB signaling and significant decrease in IL-6 secretion. Furthermore, tumors implanted with LDOC1- transduced cells in vivo were out competed by non-transduced cells, suggesting loss of LDOC1 is required for PFA tumor growth. These findings shed further light on the biology of PFA1 ependymoma and the role LDOC1 loss has on the tumor and immunobiology of high risk pediatric ependymoma.
2025-08-06 | GSE274879 | GEO
Project description:Posterior fossa molecular subtype A (PFA) ependymoma occurs in young children and is the deadliest subtype of pediatric ependymoma. High-risk subtypes with chromosome 1q+ and/or 6q- exhibit significantly poorer outcome compared to wild-type PFA. However, 50% of wild-type PFA patients relapse and there is a high risk of gaining chromosome 1q at recurrence. We previously found constitutively active NF-kB, through loss of LDOC1, led to chronic IL-6 secretion and an overall immunosuppressive tumor microenvironment in the higher risk wild-type PFA ependymoma subset (PFA1). In this study, we delineate the mechanistic consequences of LDOC1 loss in PFA1, using our PFA ependymoma in vitro and in vivo models under normoxia and hypoxia conditions. We noted chromatin compaction by H3K27me3 at the LDOC1 loci results in loss of LDOC1 gene expression. Restoration of LDOC1 was sufficient to reduce proliferation, NF-kB signaling and significant decrease in IL-6 secretion. Furthermore, tumors implanted with LDOC1- transduced cells in vivo were out competed by non-transduced cells, suggesting loss of LDOC1 is required for PFA tumor growth. These findings shed further light on the biology of PFA1 ependymoma and the role LDOC1 loss has on the tumor and immunobiology of high risk pediatric ependymoma.
2025-08-06 | GSE274877 | GEO
Project description:RNA-seq fastq files for the 16 samples used in Michealraj et al. Cell 2020.
The samples include PFA and ST ependymoma tissues, normal pediatric brain as control and PFA ependymoma lines.
| EGAD00001006046 | EGA
Project description:PFA ependymomas are a lethal glial malignancy of the hindbrain found in babies and toddlers. Lacking any highly recurrent somatic mutations, PFAs have been proposed as a largely epigenetically driven tumor type. An almost complete lack of model systems has inhibited discovery of novel PFA therapies. Both in vitro and in vivo, the PFA hypoxic microenvironment controls the availability of specific metabolites to diminish histone methylation, and to increase both histone demethylation and acetylation at H3K27. PFA ependymoma initiates from a cell lineage in the first trimester of human development where there is a known hypoxic microenvironment. Unique to PFA cells, transient exposure to ambient oxygen results in irreversible cellular toxicity. PFA tumors exhibit a low basal level of H3K27me3, and paradoxically inhibition of H3K27 methylation shows significant and specific activity against PFA. Targeting metabolism and/or the epigenome presents a unique opportunity for rational therapy for infants with PFA ependymoma.
2020-08-13 | PXD018191 | Pride
Project description:Childhood brain tumor ependymoma remains incurable in approximately 50 percent of cases. No oncogenic mechanism has been firmly established for the commonest ependymoma variant posterior fossa subgroup A (PFA), impeding clinical advances. Uncovering how heterogeneous cell types within the tumor microenvironment interact is crucial to a complete understanding of PFA disease progression. The underlying cellular components of the PFA tumor microenvironment have been revealed by single cell transcriptomics, identifying divergent epithelial differentiation and EMT lineages. Here we utilize spatial transcriptomics (Visium) of 14 PFA samples to chart neoplastic and immune cell architecture and identify novel biological processes.
2022-10-13 | GSE195661 | GEO
Project description:Posterior fossa A (PFA) ependymomas comprise one out of nine molecular groups of ependymoma. PFA tumors are mainly diagnosed in infants and young children, show a poor prognosis and are characterized by a lack of the repressive histone H3 lysine 27 trimethylation (H3K27me3) mark. Recently, we reported CXorf67 overexpression as hallmark of PFA ependymoma and showed that CXorf67 can interact with EZH2 thereby inhibiting polycomb repressive complex 2 (PRC2). Here, we report that the inhibitory mechanism of this interaction is similar as in diffuse midline gliomas harboring H3K27M mutations. A small, highly conserved peptide sequence located in the C-terminal region of CXorf67 mimics the H3K27M peptide and binds to the SET domain of EZH2. This interaction blocks EZH2 methyltransferase activity and causes H3K27 hypomethylation, an oncogenic mechanism that may be exploited for targeted therapy in PFA ependymoma. Based on its function, we have renamed CXorf67 into EZH2 Inhibitory Protein (EZHIP).
2019-07-08 | PXD012318 | Pride
Project description:Posterior fossa type A (PFA) ependymomas are a lethal glial malignancy of the hindbrain found in babies and toddlers. Lacking any highly recurrent somatic mutations, PFAs have been proposed as a largely epigenetically driven tumor type. An almost complete lack of model systems has inhibited discovery of novel PFA therapies. Both in vitro and in vivo, the PFA hypoxic microenvironment controls the availability of specific metabolites to diminish histone methylation, and to increase both histone demethylation and acetylation at H3K27. PFA ependymoma initiates from a cell lineage in the first trimester of human development where there is a known hypoxic microenvironment. Unique to PFA cells, transient exposure to ambient oxygen results in irreversible cellular toxicity. PFA tumors exhibit a low basal level of H3K27me3, and paradoxically inhibition of H3K27 methylation shows significant and specific activity against PFA. Targeting metabolism and/or the epigenome presents a unique opportunity for rational therapy for infants with PFA ependymoma.
2020-07-08 | GSE146426 | GEO
Project description:PFA (posterior fossa group A) ependymomas are a lethal glial malignancy of the hindbrain found in infants and toddlers. Lacking any highly recurrent somatic mutations, PFAs have been proposed as a largely epigenetically driven tumor type. An almost complete lack of model systems has inhibited discovery of novel PFA therapies. Both in vitro and in vivo, the PFA hypoxic microenvironment controls the availability of specific metabolites to diminish histone methylation, and to increase both histone demethylation and acetylation at H3K27. PFA ependymoma initiates from a cell lineage in the first trimester of human development where there is a known hypoxic microenvironment. Unique to PFA cells, transient exposure to ambient oxygen results in irreversible cellular toxicity. PFA tumors exhibit a low basal level of H3K27me3, and paradoxically inhibition of H3K27 methylation shows significant and specific activity against PFA. Targeting metabolism and/or the epigenome presents a unique opportunity for rational therapy for infants with PFA ependymoma.
2020-03-18 | GSE146858 | GEO
Project description:Pediatric ependymoma has relatively low frequencies of DNA mutations, which suggest that epigenetics may drive tumors. However, the epigenetic mechanisms for recurrent ependymoma are still poorly understood. Here, we performed longitudinal and comprehensive DNA methylation and gene expression analysis for recurrent pediatric ependymoma tumors from 10 patients, total 46 DNA methylomes (including primary tumors and matched recurrent tumors; normal pediatric brain tissues and PDOX tumors). Both RELA and PFA tumors maintained the subtype DNA methylation signatures during repeated relapses. We further identified the potential DNA methylation predictors, drivers and boosters and their potential regulated genes for recurrent ependymoma tumors. Increased DNA methylation levels within H3K4me1 enriched regions indicates disturbed functions of LSD1 gene in recurrent ependymoma tumors. Combining novel LSD1 inhibitor SYC-836 with radiation (XRT) significantly prolonged animal survival times in PDOX models of recurrent PFA ependymoma. Our PDOX models provide a unique platform for preclinical testing drugs and development of new therapy for pediatric recurrent ependymoma.
2022-07-12 | GSE156619 | GEO
Project description:Sequencing data related the PFA ependymoma study (Michealraj et al., Cell 2020), a lethal glial malignancy of the hindbrain found in babies and toddlers.
| EGAS00001004312 | EGA