Project description:We show that EWS-FLI1, an aberrant transcription factor responsible for the pathogenesis of Ewing sarcoma, reprograms gene regulatory circuits by directly inducing or directly repressing enhancers. At GGAA repeats, which lack regulatory potential in other cell types and are not evolutionarily conserved, EWS- FLI1 multimers potently induce chromatin opening, recruit p300 and WDR5, and create de novo enhancers. GGAA repeat enhancers can loop to physically interact with target promoters, as demonstrated by chromosome conformation capture assays. Conversely, EWS-FLI1 inactivates conserved enhancers containing canonical ETS motifs by displacing wild-type ETS transcription factors and abrogating p300 recruitment. ChIP-seq for of 4 histone modifications (H3K27ac, H3K4me1, H3K4me3 and H3K27me3), FLI1, p300, WDR5, ELF1 and GABPA in primary Ewing sarcomas, Ewing sarcoma cell lines (A673 and SKMNC cells), and mesenchymal stem cells (MSC). EWS-FLI1 was knocked down in Ewing sarcoma cell lines with lentiviral shRNAs (shFLI1 and shGFP control). EWS-FLI1 was expressed in MSCs with lentiviral expression vectors (pLIV EWSFLI1 or pLIV empty vector control). * Raw data not provided for the MSC and Primary Ewing sarcoma samples. *
Project description:This SuperSeries is composed of the following subset Series: GSE36857: Goldengate Methylation analysis: Ewing Sarcoma GSE36858: 5- AZA treatment of EWS cell lines Refer to individual Series
Project description:Expression profiling of Ewing sarcoma samples in the frame of the CIT program from the french Ligue Nationale Contre le Cancer (http://cit.ligue-cancer.net). Ewing sarcoma a rare pediatric tumor characterized by EWSR1-ETS fusions, is predominantly observed in populations of European ancestry. A genome-wide association study of at least 401 French ES patients compared to either 684 French or 3668 US self-described Caucasian controls consistently revealed candidate loci at chromosomes 1 and 10 (p<10-6). These loci were further replicated in two independent sets of cases and controls. Joint analysis identified rs9430161 (p=1.4x10-20; OR=2.2, CI99=1.8-2.7) 25kb upstream to TARDBP (1p36.22) and rs224278 (p=4.0x10-17 OR=1.7, CI99=1.4-1.9) 5kb upstream to EGR2 (10q21). The frequency of the major risk haplotypes in the European population were observed to be less prevalent in the African population, suggesting that variants at these loci could contribute to the differences in ES incidence observed between continents. TARDBP shares structural similarities with EWSR1 and FUS (TLS) EGR2 is an EWSR1-ETS target gene. Variants at both loci were associated with expression levels of TARDBP, ADO and EGR2. 117 Ewing sarcoma samples were profiled using affymetrix hgu133Plus2 arrays.
Project description:Ewing sarcoma is an aggressive pediatric small round cell tumor that predominantly occurs in bone. Approximately 85% of Ewing sarcomas harbor the EWS/FLI fusion protein, which arises from a chromosomal translocation, t(11:22)(q24:q12). EWS/FLI interacts with numerous lineage-essential transcription factors to maintain mesenchymal progenitors in an undifferentiated state. We previously showed that EWS/FLI binds the osteogenic transcription factor RUNX2 and prevents osteoblast differentiation. In this study, we investigated the role of another Runt-domain protein, RUNX3, in Ewing sarcoma. RUNX3 participates in mesenchymal-derived bone formation and is a context dependent tumor suppressor and oncogene. RUNX3 was detected in all Ewing sarcoma cells examined, whereas RUNX2 was detected in only 73% of specimens. Like RUNX2, RUNX3 binds to EWS/FLI via its Runt domain. EWS/FLI prevented RUNX3 from activating the transcription of a RUNX-responsive reporter, p6OSE2. Stable suppression of RUNX3 expression in the Ewing sarcoma cell line A673 delayed colony growth in anchorage independent soft agar assays and reversed expression of EWS/FLI-responsive genes. These results demonstrate an important role for RUNX3 in Ewing sarcoma. RNA-seq to compare transcriptiome of control A673 ewing sarcoma cells stably expression a non-target or RUNX3 shRNA
Project description:Identification of genes and pathways that were influenced by knock-down PRKDC in TC32 Ewing sarcoma and HCT116 colorectal carcinoma cell lines.
Project description:As the second most common malignant bone tumor in children and adolescents, Ewing sarcoma is initiated and exacerbated by a chimeric oncoprotein, most commonly, EWS-FLI1. In this study, we apply epigenomic analysis to characterize the transcription dysregulation in this cancer, focusing on the investigation of super-enhancer and its associated transcriptional regulatory mechanisms. We demonstrate that super-enhancer-associated transcripts are significantly enriched in EWS-FLI1 target genes, contribute to the aberrant transcriptional network of the disease, and mediate the exceptional sensitivity of Ewing sarcoma to transcriptional inhibition. Through integrative analysis, we identify MEIS1 as a super-enhancer-driven oncogene, which co-operates with EWS-FLI1 in transcriptional regulation, and plays a key pro-survival role in Ewing sarcoma. Moreover, APCDD1, another super-enhancer-associated gene, acting as a downstream target of both MEIS1 and EWS-FLI1, is also characterized as a novel tumor-promoting factor in this malignancy. These data delineate super-enhancer-mediated transcriptional deregulation in Ewing sarcoma, and uncover numerous candidate oncogenes which can be exploited for further understanding of the molecular pathogenesis for this disease.