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(bulk RNAseq) An extracellular vesicle-related gene expression signature identifies high-risk patients in medulloblastoma

ABSTRACT: Background: Medulloblastoma (MB) is a malignant brain tumor in childhood. It comprises four subgroups with different clinical behaviors. The aim of this study was to characterize the transcriptomic landscape of MB, both at the level of individual tumors as well as in large patient cohorts. Methods: We used a combination of single-cell transcriptomics, cell culture models and biophysical methods such as nanoparticle tracking analysis (NTA) and electron microscopy (EM), to investigate intercellular communication in the MB tumor niche. Results: Tumor cells of the SHH-MB subgroup show a differentiation blockade. These cells undergo extensive metabolic reprogramming. The gene expression profiles of individual tumor cells show a partial convergence with those of tumor-associated glial and immune cells. One possible cause is the transfer of extracellular vesicles (EVs) between cells in the tumor niche. We were able to detect EVs in co-culture models of MB tumor cells and oligodendrocytes. We also identified a gene expression signature, EVS, which shows overlap with the proteome profile of large oncosomes from prostate cancer cells. This signature is also present in MB patient samples. A high EVS expression is one common characteristic of tumors that occur in high-risk patients from otherwise very different MB subgroups or subtypes. Conclusions: With EVS, our study uncovered a novel gene expression signature that has a high prognostic significance across MB subgroups.

ORGANISM(S): Mus musculus Homo sapiens

PROVIDER: GSE159763 | GEO | 2020/12/11

REPOSITORIES: GEO

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(single-cell RNAseq) An extracellular vesicle-related gene expression signature identifies high-risk patients in medulloblastoma

Project description:Background: Medulloblastoma (MB) is a malignant brain tumor in childhood. It comprises four subgroups with different clinical behaviors. The aim of this study was to characterize the transcriptomic landscape of MB, both at the level of individual tumors as well as in large patient cohorts. Methods: We used a combination of single-cell transcriptomics, cell culture models and biophysical methods such as nanoparticle tracking analysis (NTA) and electron microscopy (EM), to investigate intercellular communication in the MB tumor niche. Results: Tumor cells of the SHH-MB subgroup show a differentiation blockade. These cells undergo extensive metabolic reprogramming. The gene expression profiles of individual tumor cells show a partial convergence with those of tumor-associated glial and immune cells. One possible cause is the transfer of extracellular vesicles (EVs) between cells in the tumor niche. We were able to detect EVs in co-culture models of MB tumor cells and oligodendrocytes. We also identified a gene expression signature, EVS, which shows overlap with the proteome profile of large oncosomes from prostate cancer cells. This signature is also present in MB patient samples. A high EVS expression is one common characteristic of tumors that occur in high-risk patients from otherwise very different MB subgroups or subtypes. Conclusions: With EVS, our study uncovered a novel gene expression signature that has a high prognostic significance across MB subgroups.

2020-12-11 | GSE127997 | GEO

Exosomes dependent immune surveillance at the metastatic niche requires BAG6

Project description:Mice were intravenously injected with extracellular vesicles (EVs) isolated from B16V wt (n=3) or BAG6KO (n=3) cells or with PBS (n=3) as a control for 4 weeks on a weekly basis. Since B-16V melanoma cells colonise the lung upon intravenous injection and referring to current literature, we hypothesise that melanoma EVs alter the (immune-) microenvironment of the lung to prepare a pre-metastatic niche. Based on current literature and own previous experiments identifying BAG6 as an immunoregulatory protein that is also involved in the biogenesis of EVs, we are particularly interested in differences between the immune signature upon wt EV treatment compared to BAG6KO EV treatment.

2019-11-29 | E-MTAB-7119 | biostudies-arrayexpress

Reliable tumor detection using cerebrospinal fluid cell-free DNA methylomes in pediatric medulloblastoma

Project description:Medulloblastoma (MB) is an embryonal tumor of the cerebellum and a highly malignant childhood brain tumor. Cell-free circulating tumor DNA (ctDNA) from the cerebrospinal fluid (CSF) of patients with brain tumors faithfully represent genomic alterations of brain tumors. Distinct epigenetic signatures among subgroups of MB allow us to detect epigenetic alterations in CSF to aid classify and guide therapy of MB tumors. Here, we evaluate DNA methylation and hydroxymethylation of ctDNA derived from small amount of CSF (200 µL) and matched tumor DNA from 3 MB patients. We find highly concordance of DNA methylation and hydroxymethylation between CSF ctDNA and tumor DNA, especially in CpG islands. Importantly, CSF ctDNA can mostly recapitulate the dynamic changes of DNA methylation and hydroxymehtylation in tumor species compared to healthy cerebellums. Those MB tumor signature CpGs’ DNA methylation status are recovered in CSF ctDNA can clearly distinguish MB subgroups by utilizing public large cohort data. We further identified potential diagnostic and prognostic DNA methylation markers in CSF ctDNA. Our results show that CSF ctNDA methylation and hydroxymethylation can be a minimal invasive method to assess epigenetic alterations of MB, which is complementary to current diagnoses of MB tumors.

2020-10-28 | GSE142241 | GEO

Characterization of tumor extracellular vesicle RNA cargo

Project description:Comparative RNA profiling between tumor cells and their secreted extracellular vesicles. Results revealed enrichment in genes involved in cellular migration and metastasis in extracellular vesicles, in agreement with their role as mediators of tumor progression. Mice were orthotoplically transplanted with MDA-MB-231 Breast Adenocarcinoma cells. Cells and extracellular vesicles (EVs) from the resulting tumors were isolated. EVs were characterized by electron microscopy and Nanoparticle Tracking Analysis before total RNA isolation for comparative analysis with cellular RNA. Three biological replicates were analyzed in (technical) duplicate.

2015-03-05 | E-GEOD-66488 | biostudies-arrayexpress

Proteomic analysis of human Medulloblastoma reveals distinct activated pathways between subgroups

Project description:Deregulations in fundamental signaling pathways are key events in pathogenesis of cancer. One intriguing illustration that still holds blind spots is the pediatric brain tumor arising from the developing cerebellum: medulloblastoma (MB). Extensive high-throughput sequencing led to the characterization of four MB subgroups (WNT, SHH, Group 3 and Group 4) delineated with distinct molecular signatures and clinical outcomes. However, up-to-date these analyses have not attained the global comprehension of their dynamic network complexity. Wishing to uncover a comprehensive view of all MB subgroups we employed a proteomic analysis to integrate accurate protein expression and activity that should ultimately give rise to a realistic picture of how MB cancer cells are regulated. In this study we present the first analysis regrouping methylation status, whole-transcriptome sequencing and quantitative proteomics (proteome and phosphoproteome) using a super SILAC / spiked in strategy across 38 flash frozen primary human MBs (5 WNT, 10 SHH, 10 Group 3 and 13 Group 4). First, our data pinpointed that proteomic analysis could reveal MB subgroup identity. Second, analysis of proteome and phosphoproteome highlighted disregulated signaling pathways that have not been predicted by transcriptomic analysis. Altogether, combined multi-scale analyses of MB have allowed us to identify unrevealed pathways involved in human MB genesis and progression.

2020-07-23 | PXD006607 | Pride

A microRNA signature identifies four subtypes of triple-negative breast cancer I

Project description:Triple negative breast cancer (TNBC) represents a challenging tumor type due to their poor prognosis and limited treatment options. It is well recognize that clinical and molecular heterogeneity of TNBC is driven in part by post-transcriptional regulators such as miRNAs. To stratify TNBCs, we profiled 1050 miRNAs in 132 adjuvant TNBC tumors and 40 tumors from other immunophenotypes using an Affymetrix microarray platform. A NMF clustering analysis allowed us to identify 4 TNBC subtypes featuring unique miRNA expression patterns, disease free and overall survival rates and particular gene ontology enrichments (performed with GSEA algorithm). Our agglomerative approach was cross-validated by using two other clustering algorithms (k-means and consensus clustering). TNBC miRNAs subgroups were also correlated with the Lehmann intrinsic subtypes, finding a significant enrichment of immmnomodulartory and basal 1 subtypes in our high risk miRNA subgroups. 3 cell line models (MDA MB 468, MDA MB 231 and HS578T) were classified according to our miRNA signature, recapitulating two different miRNA subgroups. The TNBC tumors were compared against other phenotypes identifying differentially expressed miRNAs that together with the altered miRNAs within the subgroups allowed us to define interesting miRNAs for further functional analysis.

2018-08-16 | GSE86277 | GEO

miRNA expression in triple negative tumors

2018-08-31 | GSE86278 | GEO

A microRNA signature identifies four subtypes of triple-negative breast cancer II

2018-08-16 | GSE86281 | GEO

Gain-of-Function p53 Protein Transferred via Small Extracellular Vesicles Promotes Conversion of Fibroblasts to a Cancer-Associated Phenotype

Project description:Crosstalk between tumor and stromal cells is essential for tumor pathogenesis. Tumor and stromal interactions consist of reciprocal signaling through cytokines, growth factors, direct cell-cell interactions, and extracellular vesicles (EVs), among others. Small EVs (≤200 nm) have been considered critical messengers of cellular communication during tumor development. Here, we demonstrated that gain-of-function (GOF) p53 protein can be packaged into small EVs and transferred to stromal cells. In this study, we performed RNA sequencing to explore the gene signature alterations in small EVs after knockdown GOF p53 expression.

2020-11-18 | GSE148698 | GEO

Gene expression profiles of different subpopulations of hepatocellular carcinoma

Project description:To demonstrate CD133+CD44+ and CD133+CD44- subpopulations of hepatocellular carcinoma as distinct subgroups, we have employed whole genome microarray expression profiling as a discovery platform to reveal the gene profiles of different subgroups and identify genes responsible for the enhanced metastatic potentials of CD133+CD44+ tumor cells. CD133+CD44+ and CD133+CD44- tumor cells were isolated from three human metastatic hepatocellular carcinoma specimens. A 76-gene consensus signature was identified that distinguished between CD133+CD44+ and CD133+CD44- subgroups. CD133+CD44+ and CD133+CD44- subgroups from different patients were well clustered as two distinct classes according to this signature, and many genes in this signature were reported involved in tumor metastasis. Expression of four genes (CCL4, DKK3, CCR5 and MMP12) from this signature was confirmed in another three metastatic HCC specimens by real-time PCR.

2010-12-28 | GSE26321 | GEO

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