Project description:Ependymoma (EPN) is a type of brain tumour.. Here we present a novel subtype of spinal ependymoma, that shows an anaplastic morphology, OLIG2 and MYCN positvity in immunostaining and a distinct epigenetic and proteomic profile.
Project description:Purpose: Myxopapillary ependymoma (MPE) is a distinct histological variant of ependymoma arising commonly in the spinal cord. Despite an overall favorable prognosis, distant metastases, subarachnoid dissemination, and late recurrences have been reported. Currently the only effective treatment for MPE is gross-total resection. We characterized the genomic and transcriptional landscape of spinal ependymomas in an effort to delineate the genetic basis of this disease and identify new leads for therapy. Experimental Design: Gene expression profiling was performed on 35 spinal ependymomas. Functional validation experiments were performed on tumour lysates consisting of assays measuring Pyruvate Kinase M activity (PKM), Hexokinase activity (HK), and lactate production. Results: At a gene expression level, we demonstrate that spinal Grade II and MPE are molecularly and biologically distinct. These findings are supported by specific copy number alterations occurring in each histological variant. Pathway analysis revealed that MPE are characterized by increased cellular metabolism, associated with up-regulation of HIF-1α. These findings were validated by western blot analysis demonstrating increased protein expression of HIF-1α, HK2, PDK1, and phosphorylation of PDHE1A. Functional assays were performed on MPE lysates, which demonstrated decreased PKM activity, increased HK activity, and elevated lactate production. Conclusions: Our findings suggest that MPE may be driven by a Warburg metabolic phenotype. The key enzymes promoting the Warburg phenotype: HK2, PKM2, and PDK are targetable by small molecule inhibitors/activators, and should be considered for evaluation in future clinical trials for MPE. RNA from 35 primary spinal ependymomas (fresh frozen) were isolated by pulverization in liquid nitrogen, and extraction using the Trizol Method (Invitrogen) [PMID:21840481]
Project description:Ependymomas of the spinal cord are rare among children and adolescents, and the individual risk of disease progression is difficult to predict. This study aims at evaluating the prognostic impact of molecular typing of pediatric spinal cord ependymomas. Eighty-three patients with spinal ependymomas ≦ 22 years registered in the HIT-MED database between 1992 and 2022 were included. Forty-seven tumors were analyzed by DNA methylation array profiling. In six cases, HOXB13 and MYCN proteins were detected as surrogate markers for specific methylation classes. With a median follow-up time of 4.9 years (y), 5y- and 10y-overall survival (OS) were 100% and 86%, while 5y- and 10y-progression-free survival (PFS) were 65% and 54%. Myxopapillary ependymoma (SP-MPE, n=32, 63%) was the most common molecular type followed by spinal ependymoma (SP-EPN, n=17, 33%) and MYCN-amplified ependymoma (n=2, 4%). One case could not be molecularly classified, and one was reclassified as anaplastic pilocytic astrocytoma. 5y-PFS did not significantly differ between SP-MPE and SP-EPN (65% versus 78%, p=0.64). MYCN-amplification was associated with early relapses (<2.3y) in both cases and death in one patient. Patients with SP-MPE subtype B (n=9) showed a non-significant trend for better 5y-PFS compared to subtype A (n=18; 86% versus 56%, p=0.15). The extent of resection and WHO tumor grades significantly influenced PFS in a uni- and multivariate analysis.
Project description:Purpose: Myxopapillary ependymoma (MPE) is a distinct histological variant of ependymoma arising commonly in the spinal cord. Despite an overall favorable prognosis, distant metastases, subarachnoid dissemination, and late recurrences have been reported. Currently the only effective treatment for MPE is gross-total resection. We characterized the genomic and transcriptional landscape of spinal ependymomas in an effort to delineate the genetic basis of this disease and identify new leads for therapy. Experimental Design: Gene expression profiling was performed on 35 spinal ependymomas. Functional validation experiments were performed on tumour lysates consisting of assays measuring Pyruvate Kinase M activity (PKM), Hexokinase activity (HK), and lactate production. Results: At a gene expression level, we demonstrate that spinal Grade II and MPE are molecularly and biologically distinct. These findings are supported by specific copy number alterations occurring in each histological variant. Pathway analysis revealed that MPE are characterized by increased cellular metabolism, associated with up-regulation of HIF-1α. These findings were validated by western blot analysis demonstrating increased protein expression of HIF-1α, HK2, PDK1, and phosphorylation of PDHE1A. Functional assays were performed on MPE lysates, which demonstrated decreased PKM activity, increased HK activity, and elevated lactate production. Conclusions: Our findings suggest that MPE may be driven by a Warburg metabolic phenotype. The key enzymes promoting the Warburg phenotype: HK2, PKM2, and PDK are targetable by small molecule inhibitors/activators, and should be considered for evaluation in future clinical trials for MPE.
Project description:The two most prevalent types of spinal ependymal tumors are myxopapillary ependymomas (MPE) and spinal ependymomas (SP-EPN). Based on molecular data from bulk tumor samples, we previously identified clinically relevant subtypes with poor (MPE-A; SP-EPN-A) and favorable progression-free survival (MPE-B; SP-EPN-B). However, detailed cellular compositions, molecular heterogeneity, and features of tumor progression are largely unknown. We performed single nucleus transcriptomic sequencing of 25 formalin-fixed and paraffin-embedded spinal ependymal tumors including all MPE and SP-EPN subtypes as well as six paired primary and relapsed MPE-A. Ependymoma subtypes presented with a broad, but comparable tumor microenvironment. Furthermore, neoplastic cells demonstrated inter- and intratumoral heterogeneity regarding cancer cell state composition. Overall, MPE tumors exhibited a significantly higher abundance of the astrocytic state, whereas a ciliated state was more prevalent in SP-EPN. Also, transcriptome-inferred copy number profiles revealed tumor cell clusters with distinct chromosomal alterations across tumors, suggesting subclonal neoplastic growth. Compared to normal human spinal cord cell populations, MPE tumor cells displayed similarities to astrocytes and ependymal cells, whereas SP-EPN exclusively matched ependymal cells. MPE-A demonstrated a distinct profile, being similar to the roof and floor plate of the developing spinal cord. Paired primary and relapsed MPE-A revealed mostly similar histology, epigenetics, copy number profiles, and cellular composition of neoplastic cells. Single nucleus transcriptomic sequencing provides valuable insights into the molecular composition of spinal ependymoma types and subtypes and may pave the way for a better understanding of tumor evolution and identification of therapeutic targets.
Project description:The two most prevalent types of spinal ependymal tumors are myxopapillary ependymomas (MPE) and spinal ependymomas (SP-EPN). Based on molecular data from bulk tumor samples, we previously identified clinically relevant subtypes with poor (MPE-A; SP-EPN-A) and favorable progression-free survival (MPE-B; SP-EPN-B). However, detailed cellular compositions, molecular heterogeneity, and features of tumor progression are largely unknown. We performed single nucleus transcriptomic sequencing of 25 formalin-fixed and paraffin-embedded spinal ependymal tumors including all MPE and SP-EPN subtypes as well as six paired primary and relapsed MPE-A. Ependymoma subtypes presented with a broad, but comparable tumor microenvironment. Furthermore, neoplastic cells demonstrated inter- and intratumoral heterogeneity regarding cancer cell state composition. Overall, MPE tumors exhibited a significantly higher abundance of the astrocytic state, whereas a ciliated state was more prevalent in SP-EPN. Also, transcriptome-inferred copy number profiles revealed tumor cell clusters with distinct chromosomal alterations across tumors, suggesting subclonal neoplastic growth. Compared to normal human spinal cord cell populations, MPE tumor cells displayed similarities to astrocytes and ependymal cells, whereas SP-EPN exclusively matched ependymal cells. MPE-A demonstrated a distinct profile, being similar to the roof and floor plate of the developing spinal cord. Paired primary and relapsed MPE-A revealed mostly similar histology, epigenetics, copy number profiles, and cellular composition of neoplastic cells. Single nucleus transcriptomic sequencing provides valuable insights into the molecular composition of spinal ependymoma types and subtypes and may pave the way for a better understanding of tumor evolution and identification of therapeutic targets.
Project description:Giant cell ependymoma (GCE), a rare ependymoma subtype, was only recently recognised as a separate diagnostic entity with variations both in malignant potential and in course of disease. The pathogenetic mechanisms behind ependymomas remain unknown. Only one karyotyped GCE has so far been reported. We present the first genomic characterisation of a supratentorial GCE using G-band karyotyping, DNA ploidy analysis and array comparative genomic hybridisation (aCGH). The G-banded karyotype was hypodiploid with multiple monosomies, a feature present also in the previously published case and, hence, probably characteristic of these tumours. We could also analyse cytogenetically a subsequent recurrent tumour, phenotypically an anaplastic ependymoma, but exhibiting a pattern of monosomies largely similar to that found in the primary tumour, allowing a first insight into the genetic events involved also in disease progression. 2 tumour samples analysed with the control DNA (supplied by Agilent)
Project description:Giant cell ependymoma (GCE), a rare ependymoma subtype, was only recently recognised as a separate diagnostic entity with variations both in malignant potential and in course of disease. The pathogenetic mechanisms behind ependymomas remain unknown. Only one karyotyped GCE has so far been reported. We present the first genomic characterisation of a supratentorial GCE using G-band karyotyping, DNA ploidy analysis and array comparative genomic hybridisation (aCGH). The G-banded karyotype was hypodiploid with multiple monosomies, a feature present also in the previously published case and, hence, probably characteristic of these tumours. We could also analyse cytogenetically a subsequent recurrent tumour, phenotypically an anaplastic ependymoma, but exhibiting a pattern of monosomies largely similar to that found in the primary tumour, allowing a first insight into the genetic events involved also in disease progression.
Project description:Hi-C and RNA-seq for a large cohort of pediatric brain tumors including ependymoma (PFA, PFB, Ste, spinal), medulloblastoma (G3, G4, SHH), high grade glioma (H3K27 and H3-WT), pilocytic astrocytoma, and more.