Similar Datasets
Project description:Tumor cell identity is the product of complex interactions between oncogenic drivers and mechanisms regulating normal differentiation pathways. Cell fate transitions observed in embryonic development involve structural changes in genomic organization that provide proper lineage specification, however, whether similar events also occur within tumor cells and contribute to cancer evolution remains largely unexplored. Here we modeled this process in the pediatric bone cancer Ewing sarcoma and investigated high resolution looping and large-scale 3D nuclear conformation changes associated with EWS-FLI1, the oncogenic fusion protein that drives this tumor. We find that chromatin interactions in Ewing sarcoma cells are dominated by highly connected looping hubs centered on EWS-FLI1 binding sites, which directly control the activity of linked enhancers and promoters to establish oncogenic expression programs. Depletion of EWS-FLI1 leads to the loss of looping networks associated with the fusion protein and, strikingly, also results in widespread nuclear reorganization through the establishment of new patterns of looping and large-scale inter-compartment connectivity that resemble the chromatin configuration of mesenchymal stem cells, a candidate cell of origin of this tumor. Our data thus demonstrate that major architectural features of nuclear organization in cancer cells can be linked to a single oncogenic event and readily reversed to re-establish latent differentiation programs.
2023-03-16 | GSE193828 | GEO
Project description:Tumor cell identity is the product of complex interactions between oncogenic drivers and mechanisms regulating normal differentiation pathways. Cell fate transitions observed in embryonic development involve structural changes in genomic organization that provide proper lineage specification, however, whether similar events also occur within tumor cells and contribute to cancer evolution remains largely unexplored. Here we modeled this process in the pediatric bone cancer Ewing sarcoma and investigated high resolution looping and large-scale 3D nuclear conformation changes associated with EWS-FLI1, the oncogenic fusion protein that drives this tumor. We find that chromatin interactions in Ewing sarcoma cells are dominated by highly connected looping hubs centered on EWS-FLI1 binding sites, which directly control the activity of linked enhancers and promoters to establish oncogenic expression programs. Depletion of EWS-FLI1 leads to the loss of looping networks associated with the fusion protein and, strikingly, also results in widespread nuclear reorganization through the establishment of new patterns of looping and large-scale inter-compartment connectivity that resemble the chromatin configuration of mesenchymal stem cells, a candidate cell of origin of this tumor. Our data thus demonstrate that major architectural features of nuclear organization in cancer cells can be linked to a single oncogenic event and readily reversed to re-establish latent differentiation programs.
2023-03-16 | GSE193824 | GEO
Project description:Tumor cell identity is the product of complex interactions between oncogenic drivers and mechanisms regulating normal differentiation pathways. Cell fate transitions observed in embryonic development involve structural changes in genomic organization that provide proper lineage specification, however, whether similar events also occur within tumor cells and contribute to cancer evolution remains largely unexplored. Here we modeled this process in the pediatric bone cancer Ewing sarcoma and investigated high resolution looping and large-scale 3D nuclear conformation changes associated with EWS-FLI1, the oncogenic fusion protein that drives this tumor. We find that chromatin interactions in Ewing sarcoma cells are dominated by highly connected looping hubs centered on EWS-FLI1 binding sites, wmicroCh directly control the activity of linked enhancers and promoters to establish oncogenic expression programs. Depletion of EWS-FLI1 leads to the loss of looping networks associated with the fusion protein and, strikingly, also results in widespread nuclear reorganization through the establishment of new patterns of looping and large-scale inter-compartment connectivity that resemble the chromatin configuration of mesenchymal stem cells, a candidate cell of origin of this tumor. Our data thus demonstrate that major architectural features of nuclear organization in cancer cells can be linked to a single oncogenic event and readily reversed to re-establish latent differentiation programs.
2023-03-16 | GSE211776 | GEO
Project description:Tumor cell identity is the product of complex interactions between oncogenic drivers and mechanisms regulating normal differentiation pathways. Cell fate transitions observed in embryonic development involve structural changes in genomic organization that provide proper lineage specification, however, whether similar events also occur within tumor cells and contribute to cancer evolution remains largely unexplored. Here we modeled this process in the pediatric bone cancer Ewing sarcoma and investigated high resolution looping and large-scale 3D nuclear conformation changes associated with EWS-FLI1, the oncogenic fusion protein that drives this tumor. We find that chromatin interactions in Ewing sarcoma cells are dominated by highly connected looping hubs centered on EWS-FLI1 binding sites, which directly control the activity of linked enhancers and promoters to establish oncogenic expression programs. Depletion of EWS-FLI1 leads to the loss of looping networks associated with the fusion protein and, strikingly, also results in widespread nuclear reorganization through the establishment of new patterns of looping and large-scale inter-compartment connectivity that resemble the chromatin configuration of mesenchymal stem cells, a candidate cell of origin of this tumor. Our data thus demonstrate that major architectural features of nuclear organization in cancer cells can be linked to a single oncogenic event and readily reversed to re-establish latent differentiation programs.
2023-03-16 | GSE193823 | GEO
Project description:The EWS-FLI1 fusion oncoprotein deregulates transcription to initiate the paediatric cancer Ewing sarcoma. Here we used a domain-focused CRISPR screen to implicate the transcriptional repressor ETV6 as a unique dependency in this tumour. Using biochemical assays and epigenomics, we show that ETV6 competes with EWS-FLI1 for binding to select DNA elements enriched for short GGAA repeat sequences. Upon inactivating ETV6, EWS-FLI1 overtakes and hyper-activates these cis-elements to promote mesenchymal differentiation, with SOX11 being a key downstream target. We show that squelching of ETV6 with a dominant-interfering peptide phenocopies these effects and suppresses Ewing sarcoma growth in vivo. These findings reveal targeting of ETV6 as a strategy for neutralizing the EWS-FLI1 oncoprotein by reprogramming of genomic occupancy.
| S-EPMC10101761 | biostudies-literature
Project description:Ewing sarcoma is an aggressive paediatric cancer of the bone and soft tissue. It results from a chromosomal translocation, predominantly t(11;22)(q24:q12), that fuses the N-terminal transactivation domain of the constitutively expressed EWSR1 protein with the C-terminal DNA binding domain of the rarely expressed FLI1 protein. Ewing sarcoma is highly sensitive to genotoxic agents such as etoposide, but the underlying molecular basis of this sensitivity is unclear. Here we show that Ewing sarcoma cells display alterations in regulation of damage-induced transcription, accumulation of R-loops and increased replication stress. In addition, homologous recombination is impaired in Ewing sarcoma owing to an enriched interaction between BRCA1 and the elongating transcription machinery. Finally, we uncover a role for EWSR1 in the transcriptional response to damage, suppressing R-loops and promoting homologous recombination. Our findings improve the current understanding of EWSR1 function, elucidate the mechanistic basis of the sensitivity of Ewing sarcoma to chemotherapy (including PARP1 inhibitors) and highlight a class of BRCA-deficient-like tumours.
| S-EPMC6318124 | biostudies-literature
Project description:Ewing sarcoma (EwS) is a rare and predominantly pediatric malignancy of bone and soft tissue in children and adolescents. Although international collaborations have greatly improved the prognosis of most EwS, the occurrence of macrometastases or relapse remains challenging. The prototypic oncogene EWS-FLI1 acts as an aberrant transcription factor that drives the cellular transformation of EwS. In addition to its involvement in RNA splicing and the DNA damage response, this chimeric protein directly binds to GGAA repeats, thereby modifying the transcriptional profile of EwS. Direct pharmacological targeting of EWS-FLI1 is difficult because of its intrinsically disordered structure. However, targeting the EWS-FLI1 protein complex or downstream pathways provides additional therapeutic options. This review describes the EWS-FLI1 protein partners and downstream pathways, as well as the related target therapies for the treatment of EwS.
| S-EPMC10452796 | biostudies-literature
Project description:Cohesin complexes carrying STAG1 or STAG2 organize the genome into chromatin loops. STAG2 loss-of-function mutations promote metastasis in Ewing sarcoma, a pediatric cancer driven by the fusion transcription factor EWS::FLI1. We integrated transcriptomic data from patients and cellular models to identify a STAG2-dependent gene signature associated with worse prognosis. Subsequent genomic profiling and high-resolution chromatin interaction data from Capture Hi-C indicated that cohesin-STAG2 facilitates communication between EWS::FLI1-bound long GGAA repeats, presumably acting as neoenhancers, and their target promoters. Changes in CTCF-dependent chromatin contacts involving signature genes, unrelated to EWS::FLI1 binding, were also identified. STAG1 is unable to compensate for STAG2 loss and chromatin-bound cohesin is severely decreased, while levels of the processivity factor NIPBL remain unchanged, likely affecting DNA looping dynamics. These results illuminate how STAG2 loss modifies the chromatin interactome of Ewing sarcoma cells and provide a list of potential biomarkers and therapeutic targets.
| S-SCDT-10_1038-S44319-024-00303-6 | biostudies-other
Project description:Ewing sarcoma is the second most common pediatric bone and soft tissue tumor presenting with an aggressive behavior and prevalence to metastasize. The diagnostic translocation t(22;11)(q24;12) leads to expression of the chimeric oncoprotein EWS-FLI1 which is uniquely expressed in all tumor cells and maintains their survival. Constant EWS-FLI1 protein turnover is regulated by the ubiquitin proteasome system. Here, we now identified ubiquitin specific protease 19 (USP19) as a regulator of EWS-FLI1 stability using an siRNA based screening approach. Depletion of USP19 resulted in diminished EWS-FLI1 protein levels and, vice versa, upregulation of active USP19 stabilized the fusion protein. Importantly, stabilization appears to be specific for the fusion protein as it could not be observed neither for EWSR1 nor for FLI1 wild type proteins even though USP19 binds to the N-terminal EWS region to regulate deubiquitination of both EWS-FLI1 and EWSR1. Further, stable shUSP19 depletion resulted in decreased cell growth and diminished colony forming capacity in vitro, and significantly delayed tumor growth in vivo. Our findings not only provide novel insights into the importance of the N-terminal EWSR1 domain for regulation of fusion protein stability, but also indicate that inhibition of deubiquitinating enzyme(s) might constitute a novel therapeutic strategy in treatment of Ewing sarcoma.
| S-EPMC6353870 | biostudies-literature
Project description:Genome wide enhancer loops (HiChIP) and 3-D high order chromatin features associated with EWS-FLI1 in Ewing Sarcoma. [HiChIP]
| PRJNA798049 | ENA