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: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. 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.
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:Transient transfection of a Ewing's Sarcoma cell line expressing type I EWS-FLI1 fusion and doxycycline-inducible short hairpin RNA against EWS-FLI1 (A673sh)
Project description:Transient transfection of a Ewing's Sarcoma cell line expressing type I EWS-FLI1 fusion and doxycycline-inducible short hairpin RNA against EWS-FLI1 (A673sh) In total, 7 samples were analysed: empty vector control and two nuclear directed AKT- and CDK2- phosphorylation resistant FOXO1 versions as well as sh-scrambled and sh-FOXO1, either in the presence (w.o. Doxy.) or absence of EWS-FLI1 (+ Doxy.) each 2 replicates
Project description:Translocations of ETS transcription factors are driver mutations in diverse cancers. We investigated the genomic network of the ETS fusion EWS/FLI1 in Ewing's sarcoma (ESFT) as a model of ETS-driven tumorigenesis. ChIP-Seq and transcriptional analysis identified E2F3 as a principle co-factor of EWSFLI1 defining functionally distinct gene sets. While EWS/FLI1 binding independent of E2F3 predominantly associated with repressed differentiation genes, significant co-localization with E2F3 was discovered at proximal promoters of activated growth-related genes. Thus, EWS/FLI1 promotes oncogenesis by simultaneously perturbing differentiation state and augmenting the expression of genes co-regulated by E2F3. Integration of additional E2F3 and ERG localization data from prostate cancer containing TMPRSS2/ERG verified that the ETS-E2F module is also found in prostate cancer and may be of general relevance to ETS driven cancers. Timecourse with 6 timepoints of a doxicyclin inducible EWS-FLI1 knockdown in the A673 Ewing's Sarcoma celline
Project description:The synthesis and processing of mRNA, from transcription to translation initiation, often requires splicing of intragenic material. The final mRNA composition varies based upon proteins that modulate splice site selection. EWS-FLI1 is an Ewing sarcoma (ES) oncogene with an interactome that we demonstrate to have multiple partners in spliceosomal complexes. We evaluate EWS-FLI1 upon post-transcriptional gene regulation using both exon array and RNA-seq. Genes that potentially regulate oncogenesis including CLK1, CASP3, PPFIBP1, and TERT validate as alternatively spliced by EWS-FLI1. EWS-FLI1 also alters splicing by directly binding to known splicing factors including DDX5, hnRNPK, and PRPF6. Reduction of EWS-FLI1 produces an isoform of g-TERT that has increased telomerase activity compared to WT TERT. The small molecule YK-4-279 is an inhibitor of EWS-FLI1 oncogenic function that disrupts specific protein interactions including DDX5 and RNA helicase A (RHA) that alters RNA splicing ratios. As such, YK-4-279 validates the splicing mechanism of EWS-FLI1 showing alternatively spliced gene patterns that significantly overlap with EWS-FLI1 reduction and WT human mesenchymal stem cells. Exon array analysis of 75 ES patient samples show similar isoform expression patterns to cell line models expressing EWS-FLI1, supporting the clinical relevance of our findings. These experiments establish systemic alternative splicing as an oncogenic process modulated by EWS-FLI1. EWS-FLI1 modulation of mRNA splicing may provide insight into the contribution of splicing towards oncogenesis, and reciprocally, EWS-FLI1 interactions with splicing proteins may inform the splicing code. Alternative splicing of RNA allows a limited number of coding regions in the human genome to produce proteins with diverse functionality. Alternative splicing has also been implicated as an oncogenic process. Identifying aspects of cancer cells that differentiate them from non-cancer cells remains an ongoing challenge and our research suggests that alternatively spliced mRNA and subsequent protein isoforms will provide new anti-cancer targets. We determined that the key oncogene of Ewing sarcoma (ES), EWS-FLI1, regulates alternative splicing in multiple cell line models. These experiments establish oncogenic aspects of splicing which are specific to cancer cells and thereby illuminate potentially oncogenic splicing shifts as well as provide a useful stratification mechanism for ES patients. We analyzed three models of EWS-FLI1 using Affymetrix GeneChip Human Exon 1.0 ST microarray: (i) Ewing's sarcoma TC32 wild-type cells expressing EWS-FLI1, and TC32 cells where EWS-FLI1 was reduced with a lentiviral shRNA; (ii) A673i, which has a doxycycline-inducible shRNA to reduce EWS-FLI1 expression, and wild-type EWS-FLI1 to screen for alternative splicing as measured by exon-specific expression changes; and (iii) human mesenchymal stem cells (hMSC), a putative cell of origin of Ewing's sarcoma, exogenously expressing EWS-FLI1, and hMSC wild-type cells without EWS-FLI1. Three biological replicates were included for each condition. The Bioconductor package "oligo" in the R programming language was used for normalization and background correction. Analysis was carried out using only core probesets, as defined by the manufacturer.