Project description:Background Primitive brain tumors are the first cause of cancer-related death in children. Tumor cells with stem-like properties (TSCs), thought to account for tumorigenesis and therapeutic resistance, have been isolated from high-grade gliomas in adults. Whether TSCs are a common component of pediatric brain tumors and are of clinical relevance remains to be determined. Methodology/Principal findings Tumor cells with self-renewal properties were isolated with cell biology techniques from a majority of 55 pediatric brain tumors samples, regardless of their histopathologies and grades of malignancy (57% of embryonal tumors, 57% of low-grade gliomas and neuro-glial tumors, 70% of ependymomas, 91% of high-grade gliomas). The vast majority (10/12) of high-grade glioma-derived oncospheres sustained long-term self-renewal numbers akin to neural stem cells (>7 self-renewals), whereas cells with limited renewing abilities akin to neural progenitors dominated in all other tumor types. Regardless of tumor entities, the young age group was associated with self-renewal properties akin to neural stem cells (P=0.05, chi-square test). TSCs shared a complex molecular profile combining embryonic stem cell markers with elements controlling neural stem cell properties and epithelio-mesenchymal transitions. They were radio- and chemoresistant and formed aggressive tumors after intracerebral grafting. Survival analysis of the cohort showed an association between isolation of TSCs with long-term self-renewal abilities and a patientM-^Rs higher mortality rate (P = 0.022, log-rank test). Patients bearing cells with limited self-renewal properties constituted an intermediate group of survival but which did not reach statistical significance. Conclusions/Significance In brain tumors affecting adult patients, TSC have been isolated only from high-grade gliomas. In contrast, our data show that tumor cells with stem cell-like or progenitor-like properties can be isolated from a wide range of histological sub-types and grades of pediatric brain tumors. They suggest that cellular mechanisms fueling tumor development differ between adult and pediatric brain tumors.

Project description:Background Primitive brain tumors are the first cause of cancer-related death in children. Tumor cells with stem-like properties (TSCs), thought to account for tumorigenesis and therapeutic resistance, have been isolated from high-grade gliomas in adults. Whether TSCs are a common component of pediatric brain tumors and are of clinical relevance remains to be determined. Methodology/Principal findings Tumor cells with self-renewal properties were isolated with cell biology techniques from a majority of 55 pediatric brain tumors samples, regardless of their histopathologies and grades of malignancy (57% of embryonal tumors, 57% of low-grade gliomas and neuro-glial tumors, 70% of ependymomas, 91% of high-grade gliomas). The vast majority (10/12) of high-grade glioma-derived oncospheres sustained long-term self-renewal numbers akin to neural stem cells (>7 self-renewals), whereas cells with limited renewing abilities akin to neural progenitors dominated in all other tumor types. Regardless of tumor entities, the young age group was associated with self-renewal properties akin to neural stem cells (P=0.05, chi-square test). TSCs shared a complex molecular profile combining embryonic stem cell markers with elements controlling neural stem cell properties and epithelio-mesenchymal transitions. They were radio- and chemoresistant and formed aggressive tumors after intracerebral grafting. Survival analysis of the cohort showed an association between isolation of TSCs with long-term self-renewal abilities and a patients higher mortality rate (P = 0.022, log-rank test). Patients bearing cells with limited self-renewal properties constituted an intermediate group of survival but which did not reach statistical significance. Conclusions/Significance In brain tumors affecting adult patients, TSC have been isolated only from high-grade gliomas. In contrast, our data show that tumor cells with stem cell-like or progenitor-like properties can be isolated from a wide range of histological sub-types and grades of pediatric brain tumors. They suggest that cellular mechanisms fueling tumor development differ between adult and pediatric brain tumors.

Project description:Background: Molecular profiling of diffuse gliomas has provided significant insights into the pathogenesis, classification and prognostication of these malignancies. However, previous molecular studies of glioma have largely focused on genomic readouts and targeted proteomic profiling technologies. Consequently, proteomic and downstream functional landscape of gliomas in general, and molecular subgroups in particular, remains largely unexplored. Here, we utilize liquid chromatography tandem mass spectrometry to profile genomically-defined cohorts of gliomas spanning the full range of World Health Organization (WHO) grades. Methods: Bulk frozen tissue and purified micro-dissected regions from formalin-fixed paraffin-embedded (FFPE) tissues were assembled and utilized to define robust proteomic signatures of both low grade, infiltrative and high-grade tumors. As a final analysis, primary tumor tissue was compared with both IDH-mutated and IDH-wildtype glioblastoma stem cell (GSC) lines to further overcome tissue heterogeneity and pinpoint proteins differences likely arising in the relevant glial cellular drivers of tumor development. Results: In aggregate, 5,496 unique proteins over 3 glioma cohorts were identified, and span common molecular subclasses based on IDH and 1p19q co-deletion status and all four WHO grades. Supervised clustering highlights substantial proteome and systems-level pathway differences between different genetically defined glioma subtypes and WHO grades. By using bulk tumor statistical analysis, 833 proteins distinguish different WHO grade tumors, while FFPE tumor dissection reveals 287 proteins in GBMs with abundance changes according to IDH mutation status. Using our integrative approach, calcium signaling, proteins of the endoplasmic reticulum and extracellular integrin proteins are most conserved proteomic markers that distinguish aggressive, IDH-wt, from IDH-mut GBM tumors in primary and tissue culture models gliomagenesis. Conclusions: This proteomic survey provides the largest and most diverse unbiased protein-based brain tumor resource to date. Current treatments for glial tumors are largely non-specific and overlap between genomic subtypes and WHO grades. Our analysis provides early insight into the vast downstream and epigenetic protein-level differences within this molecular framework. Given the central position proteins occupy in driving biology and phenotype, further characterization of the substantial proteomic diversity that exist between the molecular subtypes and grades of gliomas, proteomics may help define more personalized prognostic and predictive biomarkers for precision care.

Dataset Information

Comparative genomic hybridization of human gliomas (178)

Publications

High-resolution global genomic survey of 178 gliomas reveals novel regions of copy number alteration and allelic imbalances.

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