Homo sapiens
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ABSTRACT:
PROVIDER: PRJNA192549 | ENA |
REPOSITORIES: ENA
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Project description:Pharmacologic Inhibition of Epigenetic Modification Reveals Targets of Aberrant Promoter Methylation in Ewing Sarcoma
2025-01-24 | E-GEOD-44934 | ExpressionAtlas
Project description:Background: Ewing sarcoma, a highly aggressive tumor of children and young adults, is characterized most commonly by an 11;22 chromosomal translocation that fuses EWSR1 located at 22q12 with FLI1, coding for a member of the ETS family of transcription factors. Although genetic changes in Ewing sarcoma have been extensively researched, our understanding of the role of epigenetic modifications in this neoplasm is limited. Procedure: In an effort to improve our knowledge in the role of epigenetic changes in Ewing sarcoma we evaluated the in vitro antineoplastic effect of the DNA methyltransferase inhibitor 5-Aza-deoxycytidine (5-Aza-dC) and identified epigenetically silenced genes by pharmacologic unmasking of DNA methylation coupled with genome-wide expression profiling.
2014-03-05 | E-GEOD-44934 | biostudies-arrayexpress
Project description:We performed reduced representation bisulfite seqeuncing (RRBS) and ChIP-seq of histone modification marks on three Ewing sarcoma tumor samples, and we quantified epigenetic heterogeneity on three levels. First, we identified a Ewing sarcoma specific hypomethylation signature at EWS-FLI1 regulated enhancers, showing that epigenetic enhancer reprogramming is a defining feature of Ewing sarcoma. Second, inter-individual DNA methylation differences in Ewing sarcoma samples identified a continuous disease spectrum with two dimensions: the strength of the EWS-FLI1 regulatory signature and the balance of mesenchymal versus stem cell regulatory signatures. Third, we observed substantial epigenetic heterogeneity within individual tumors. In summary, our study provides a comprehensive assessment of epigenetic heterogeneity in Ewing sarcoma, highlighting its importance as a source of variability for genetically homogeneous tumors.
2017-01-30 | GSE89026 | GEO
Project description:Study of promoter methylation of ewing sarcoma cell lines and mesenchymal stem cell from ewing sarcoma patients and healthy donors
2018-10-24 | GSE118872 | GEO
Project description:Developmental tumors in children and young adults carry few genetic alterations, yet they have diverse clinical presentation. Focusing on Ewing sarcoma, we sought to establish the prevalence and characteristics of epigenetic heterogeneity in genetically homogeneous cancers. We performed genome-scale DNA methylation sequencing for a large cohort of Ewing sarcoma tumors and analyzed epigenetic heterogeneity on three levels: between cancers, between tumors, and within tumors. We observed consistent DNA hypomethylation at enhancers regulated by the disease-defining EWS-FLI1 fusion protein, thus establishing epigenomic enhancer reprogramming as a ubiquitous and characteristic feature of Ewing sarcoma. DNA methylation differences between tumors identified a continuous disease spectrum underlying Ewing sarcoma, which reflected the strength of an EWS-FLI1 regulatory signature and a continuum between mesenchymal and stem cell signatures. There was substantial epigenetic heterogeneity within tumors, particularly in patients with metastatic disease. In summary, our study provides a comprehensive assessment of epigenetic heterogeneity in Ewing sarcoma and thereby highlights the importance of considering nongenetic aspects of tumor heterogeneity in the context of cancer biology and personalized medicine.
2017-01-30 | GSE88826 | GEO
Project description:Epigenetic modifications have been shown to be important in developmental tumors as Ewing sarcoma. We profiled the DNA methylation status of 15 primary tumors and 7 cell lines using the Infinium Human Methylation 450k. Differential methylation analysis between Ewing sarcoma and reference samples revealed 1,166 hypermethylated and 864 hypomethylated CpG sites (Bonferroni p<0.05, δ-β-value with absolute difference of >0.20) corresponding to 392 and 470 genes respectively. Gene Ontology analysis of genes differentially methylated in Ewing sarcoma samples showed a significant enrichment of developmental genes. Membrane and cell signal genes were also enriched, among those, 11 were related to caveola formation. We identified differential hypermethylation of CpGs located in the body and S-Shore of the PTRF gene in Ewing sarcoma that correlated with its repressed transcriptional state. Reintroduction of PTRF/Cavin-1 in Ewing sarcoma cells revealed a role of this protein as a tumor suppressor. Restoration of caveolae in the membrane of Ewing sarcoma cells, by exogenously reintroducing PTRF, disrupts the MDM2/p53 complex, which consequently results in the activation of p53 and the induction of apoptosis.
2016-11-28 | GSE89041 | GEO
Project description:Identification of druggable targets is a prerequisite for developing targeted therapies against Ewing sarcoma. We report the identification of Protein Kinase C Beta (PRKCB) as a protein specifically and highly expressed in Ewing sarcoma as compared to other pediatric cancers. Its transcriptional activation is directly regulated by the EWSR1-FLI1 oncogene. Getting insights in PRKCB activity we show that, together with PRKCA, it is responsible for the phosphorylation of histone H3T6, allowing global maintenance of H3K4 trimethylation on a variety of gene promoters. In the long term, PRKCB RNA interference induces apoptosis in vitro. More importantly, in xenograft mice models, complete impairment of tumor engraftment and even tumor regression were observed upon PRKCB inhibition, highlighting PRKCB as a most valuable therapeutic target. Deciphering PRKCB roles in Ewing sarcoma using expression profiling, we found a strong overlap with genes modulated by EWSR1-FLI1 and an involvement of RPKCB in regulating crucial signaling pathways. Altogether, we show that PRKCB may have two important independent functions and should be considered as highly valuable for understanding Ewing sarcoma biology and as a promising target for new therapeutic approaches in Ewing sarcoma. A673 Ewing cell line was treated for 72 hours by either control siRNA or siRNA directed against PRKCB or EWSR1-FLI1. Total RNAs were extracted and hybridized on HuGene1.1STv1 Affymetrix Arrays. Normalisation was performed using specific Brainarray Enrtez gene CDF file (v14.1).
2012-06-30 | E-GEOD-38392 | biostudies-arrayexpress
Project description:Ewing sarcoma (EWS) is a malignant pediatric bone cancer. Most Ewing sarcomas are driven by EWS-FLI1 oncogenic transcription factor that plays roles in transcriptional regulation, DNA damage response, cell cycle checkpoint control, and alternative splicing. USP1, a deubiquitylase which regulates DNA damage and replication stress responses, is overexpressed at both the mRNA and protein levels in EWS cell lines compared to human mesenchymal stem cells, the EWS cell of origin. The functional significance of high USP1 expression in Ewing sarcoma is not known. Here, we identify USP1 as a transcriptional target of EWS-FLI1 and a key regulator of EWS cell survival. We show that EWS-FLI1 knockdown decreases USP1 mRNA and protein levels. ChIP and ChIP-seq analyses show EWS-FLI1 occupancy on the USP1 promoter. Importantly, USP1 knockdown or inhibition arrests EWS cell growth and induces cell death by apoptosis. We observe destabilization of Survivin (also known as BIRC5 or IAP4) and activation of caspases-3 and -7 following USP1 knockdown or inhibition in the absence of external DNA damage stimuli. Notably, EWS cells display hypersensitivity to combinatorial treatment of doxorubicin or etoposide, EWS standard of care drugs, and USP1 inhibitor compared to single agents alone. Together, our study demonstrates that USP1 is regulated by EWS-FLI1, the USP1-Survivin axis promotes EWS cell survival, and USP1 inhibition sensitizes EWS cells to standard of care chemotherapy.
2024-01-26 | PXD041033 | Pride
Project description:Cancer genotyping projects have identified frequent mutations in epigenetic regulators. Ewing sarcoma is a pediatric tumor characterized by the critical translocation-associated fusion oncoprotein EWS::FLI and a low mutational burden. EWS::FLI targets characteristic genetic loci where it mediates aberrant chromatin and the establishment of de novo enhancers. Ewing sarcoma thus provides a model to interrogate mechanisms underlying chromatin dysregulation in tumorigenesis. Previously, we developed a high-throughput chromatin-based screening platform and demonstrated its utility in identifying small molecules capable of altering chromatin accessibility at EWS::FLI-bound loci. Here, we report the identification of UNC0621, a molecule with previously uncharacterized mechanism of action, as a small molecule modulator of chromatin state at sites of aberrant chromatin accessibility at EWS::FLI-bound loci. UNC0621 suppresses cellular proliferation of Ewing sarcoma cell lines by cell cycle arrest. Proteomic studies demonstrate that UNC0621 associates with RNA binding and splicing proteins as well as chromatin regulatory proteins. Surprisingly, interactions with chromatin and many RNA-binding proteins, including EWS::FLI fusion protein and its known interactors, were RNA-independent. Our findings suggest that UNC0621 affects EWS::FLI-mediated chromatin activity by interacting with and altering the activity of RNA splicing machinery and chromatin modulating factors. Genetic modulation of these proteins similarly inhibits proliferation and alters chromatin in Ewing sarcoma cells. The use of an oncogene-associated chromatin signature as a target represents a novel strategy to directly screen for modulators of epigenetic machinery and provides a framework for using chromatin-based assays for future therapeutic discovery efforts.
2023-03-13 | GSE213545 | GEO
Project description:Epigenetic alterations appear to modulate Myc signaling. We investigated the role of the histone demethylase JMJD2B in Myc-mediated neuroblastoma pathogenesis. We demonstrate that Myc physically interacts with and recruits this epigenetic modifier, which removes repressive H3K9 methyl marks from Myc-target genes. JMJD2B regulates neuroblastoma proliferation and, together with MYCN amplification, identifies a subgroup of poor prognosis patients. We identify a novel histone demethylase inhibitor, ciclopirox, which targets JMJD2B and, consequently, Myc signaling, thereby inhibiting neuroblastoma proliferation and inducing differentiation. In xenograft studies, genetic and pharmacologic inhibition of JMJD2B resulted in significant tumor growth restriction. Our findings provide insight into epigenetic regulation of Myc via histone methylation and proof-of-concept for pharmacologic inhibition of histone demethylases to target Myc signaling in cancer. 8 samples were treated with vehicle or ciclopirox.
2014-01-01 | E-GEOD-45969 | biostudies-arrayexpress