Project description:Ewing’s sarcoma (EWS) is a cancer of the bones or soft tissues in children and adolescents. EWS-FLI1 is a transcriptional factor and the key driver of EWS. To characterize the changes of downstream transcriptional profiles of EWS-FLI1 in A673 cells upon knockdown of EWS-FLI1 and deubiquitinase USP9X, RNA-seq was performed in A673 cells transfected with EWS-FLI1 esiRNA, USP9X esiRNA or GFP esiRNA as control. The data indicates that USP9X regulates transcriptional profiles of EWS through mediating EWS-FLI1.
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.
Project description:Ewing’s sarcoma is highly malignant bone tumor that involves childhood and adolescent, and its nature has not been well understood. To clarify its cellular origin and the mechanisms of tumorigenesis, we used ex vivo approach to create a murine model for Ewing’s sarcoma. The osteochondrogenic progenitors derived from the embryonic superficial zone (eSZ, designated as FZ in the data set) of murine long bones at late gestation were purified by microdissection, introduced with EWS-FLI1 or EWS-ERG retroviruses and transplanted into nude mice. Ewing’s sarcoma-like small round cell sarcoma developed at 100% penetrance, whereas tumor induction was less effective when growth place (GP)-derived cells were used. The different response of gene expression to EWS-FLI1 between eSZ and GP cells suggests importance of the specific cellular context for EWS-FLI1 to induce Ewing’s sarcoma. The Wnt/β-catenin pathway was involved in close relationship to the cellular context, with Dkk2 and Wipf1 as important downstream modulators. Furthermore, gene expression profiling revealed similarity between our models and human Ewing’s sarcoma. These results indicate that Ewing’s sarcoma originates from the embryonic osteochondrogenic progenitor.
Project description:The fusion oncoprotein EWS-FLI1 arises from a t(11;22)(q24;q12) chromosomal translocation and causes Ewing's Sarcoma, a malignant bone tumor. The mechanism whereby EWS-FLI1 transforms cells is unknown. We made germline transgenic zebrafish expressing human EWS-FLI1 under the control of the heat shock promoter. Induction of EWS-FLI1 expression causes multiple defects in embryonic development. We compared gene expression in control and transgenic EWS-FLI1 zebrafish. The results identify a conserved set of EWS-FLI1-regulated genes, and provide insight into the pathogenesis of Ewing's Sarcoma tumors. We performed heat shock and isolated total RNA for microarray studies comparing wildtype AB strain zebrafish with transgenic zebrafish expressing human EWS-FLI1 [Tg(HSP:EWS-FLI1)]. RNA was biotin-lableled and hybridized to zebrafish-specific Affymetrix arrays.
Project description:The fusion oncoprotein EWS-FLI1 arises from a t(11;22)(q24;q12) chromosomal translocation and causes Ewing's Sarcoma, a malignant bone tumor. The mechanism whereby EWS-FLI1 transforms cells is unknown. Somatic, mosaic expression of human EWS-FLI1 in zebrafish from the heat shock promoter [Tg(HSP:EWS-FLI1)] caused small round blue cell tumors (SRBCTs) similar to human Ewing's sarcoma. We performed microarray studies comparing zebrafish SRBCTs to another tumor type, zebrafish malignant peripheral nerve sheath tumors (MPNSTs). The results identify a conserved set of EWS-FLI1-regulated genes,and provide insight into the pathogenesis of Ewing's Sarcoma tumors. Zebrafish SRBCTs arising from somatic insertions of the EWS-FLI1 transgene were collected. MPNSTs from non-transgenic fish of the same genetic background were collected in parallel. RNA was prepared from all samples and hybridized to zebrafish-specific Affymetrix arrays.
Project description:The fusion oncoprotein EWS-FLI1 arises from a t(11;22)(q24;q12) chromosomal translocation and causes Ewing's Sarcoma, a malignant bone tumor. The mechanism whereby EWS-FLI1 transforms cells is unknown. We made germline transgenic zebrafish expressing human EWS-FLI1 under the control of the heat shock promoter. Induction of EWS-FLI1 expression causes multiple defects in embryonic development. We compared gene expression in control and transgenic EWS-FLI1 zebrafish. The results identify a conserved set of EWS-FLI1-regulated genes, and provide insight into the pathogenesis of Ewing's Sarcoma tumors.
Project description:The fusion oncoprotein EWS-FLI1 arises from a t(11;22)(q24;q12) chromosomal translocation and causes Ewing's Sarcoma, a malignant bone tumor. The mechanism whereby EWS-FLI1 transforms cells is unknown. Somatic, mosaic expression of human EWS-FLI1 in zebrafish from the heat shock promoter [Tg(HSP:EWS-FLI1)] caused small round blue cell tumors (SRBCTs) similar to human Ewing's sarcoma. We performed microarray studies comparing zebrafish SRBCTs to another tumor type, zebrafish malignant peripheral nerve sheath tumors (MPNSTs). The results identify a conserved set of EWS-FLI1-regulated genes,and provide insight into the pathogenesis of Ewing's Sarcoma tumors.
Project description:we report a synthetic lethality of ETV6 and EWS-FLI1 in ewing sarcome that is imposed by ETV6 antagonize EWS-FLI1 from particular GGAA microsatellite sites
Project description:This SuperSeries is composed of the following subset Series: GSE31185: The human Ewing's Sarcoma oncoprotein EWS-FLI1 causes developmental defects in zebrafish embryos GSE31186: The human Ewing's Sarcoma oncoprotein EWS-FLI1 causes Ewing's-type tumors in zebrafish Refer to individual Series
Project description:Ewing Sarcoma (EwS) is a EWS-FLI1- fusion driven pediatric bone cancer with high metastatic potential. Cellular plasticity, typically regulated via the Rho-pathway, is a prerequisite for metastasis initiation. Here we interrogated the role of the Rho transcriptional effectors MRTFA/B in EwS. We find MRTFB transcriptional function strongly repressed by EWS-FLI1. Under EWS-FLI1-low (knock-down) conditions, MRTFB is activated and antagonizes global EWS-FLI1-dependent transcription. Furthermore, ChIP-Seq revealed strong overlaps in MRTFB and EWS-FLI1 chromatin occupation, especially for EWS-FLI1 suppressed-(anticorrelated) genes. Enrichment of TEAD binding motifs in these shared genomic binding regions, and overlapping transcriptional footprints of MRTFB and TEAD1-4 perturbation led us to propose synergy between MRTFB and TEAD in the regulation of EWS-FLI1 suppressed-anticorrelated genes. Finally, we find F-actin assembly to be already perturbed in our EwS model, F-actin polymerization is perturbed by EWS-FLI1 in our model cell line, however,but pharmacological inhibition of actin polymerization still reduced expression serum-induced expression of MRTFB/YAP-1/TEAD target genes. In summary our data support a model of indirect and direct EWS-FLI1-driven perturbation of MRTFB/YAP-1/TEAD target gene regulation .