Rewiring the fusion oncoprotein EWS/FLI1 in Ewing sarcoma with bivalent small molecules [ATAC-seq]
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE290893 | GEO | 2025/03/17
REPOSITORIES: GEO
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Project description:Deregulated transcription is a defining hallmark of cancer, especially pediatric malignancies, which are frequently driven by fusion transcription factors. Targeting transcription factors directly has been challenging as they lack druggable pockets. Recently, chemically induced proximity has enabled the rewiring of transcriptional activators to drive expression of pro-apoptotic genes using bivalent small molecules. Targeting fusion transcription factors, such as EWS/FLI in Ewing sarcoma, with these compounds, may open new therapeutic venues. Here, we develop a small molecule, EB-TCIP, that recruits FKBP12F36V-tagged EWS/FLI1 to DNA sites bound by the transcriptional regulator BCL6, leading to rapid and sustained expression of BCL6 target genes. EB-TCIP activity is dependent on ternary complex formation and specific to cells that express FKBP-EWS/FLI1. This proof-of-concept study demonstrates that EWS/FLI1 can be relocalized on chromatin to induce genes that are ordinarily regulated by a transcriptional repressor. Insights herein will guide the development of bivalent molecules for fusion transcription factors.
2025-03-17 | GSE290895 | GEO
Project description:Deregulated transcription is a defining hallmark of cancer, especially pediatric malignancies, which are frequently driven by fusion transcription factors. Targeting transcription factors directly has been challenging as they lack druggable pockets. Recently, chemically induced proximity has enabled the rewiring of transcriptional activators to drive expression of pro-apoptotic genes using bivalent small molecules. Targeting fusion transcription factors, such as EWS/FLI in Ewing sarcoma, with these compounds, may open new therapeutic venues. Here, we develop a small molecule, EB-TCIP, that recruits FKBP12F36V-tagged EWS/FLI1 to DNA sites bound by the transcriptional regulator BCL6, leading to rapid and sustained expression of BCL6 target genes. EB-TCIP activity is dependent on ternary complex formation and specific to cells that express FKBP-EWS/FLI1. This proof-of-concept study demonstrates that EWS/FLI1 can be relocalized on chromatin to induce genes that are ordinarily regulated by a transcriptional repressor. Insights herein will guide the development of bivalent molecules for fusion transcription factors.
2025-03-17 | GSE290894 | GEO
Project description:Ewing sarcoma (EwS) is an adolescent and young adult sarcoma characterized by chromosome translocations between members of the FET family of RNA binding proteins and members of the ETS family of transcription factors, the most frequent fusion being EWS-FLI1. EWS-FLI1 acts as a pioneer factor, creating de novo enhancers and activating genes located in the vicinity of EWS-FLI1-bound microsatellite sequences. recent results from our lab indicate that EWS-FLI1, which activates transcription through binding to the DNA at specific sites, can generate fully novel, unconventional transcription units in regions of the genome that are fully quiescent in normal cells (manuscript in preparation). The hypothesis of the project is that the open reading frames (ORFs) of these transcripts may encode peptides presented at the cell surface by HLA class I molecules and hence be recognized as non-self by the immune system. The aim of this study is to detect Ewing-specific neo-peptides/proteins using proteomics approach.
2022-05-12 | PXD027309 | Pride
Project description:Fusion of the EWS gene to FLI1 produces a fusion oncoprotein that drives an aberrant gene expression program responsible for the development of Ewing sarcoma. We used a homogenous proximity assay to screen for compounds that disrupt the binding of EWS-FLI1 to its cognate DNA targets. A number of DNA-binding chemotherapeutic agents were found to non-specifically disrupt protein binding to DNA. In contrast, actinomycin D was found to preferentially disrupt EWS-FLI1 binding by comparison to p53 binding to their respective cognate DNA targets in vitro. In cell-based assays, low concentrations of actinomycin preferentially blocked EWS-FLI1 binding to chromatin, and disrupted EWS-FLI1-mediated gene expression. Higher concentrations of actinomycin globally repressed transcription. These results demonstrate that actinomycin preferentially disrupts EWS-FLI1 binding to DNA at selected concentrations. Although the window between this preferential effect and global suppression is too narrow to exploit in a therapeutic manner, these results suggest that base-preferences may be exploited to find DNA-binding compounds that preferentially disrupt subclasses of transcription factors. Using proximity assays in A673 Ewing Sarcoma cells, we screened 7 bioactive-enriched small molecule libraries, totaling 5,200 compounds to identify compounds that could disrupt the binding of EWS-FLI1 to its cognate DNA binding sequence. We defined a set of EWS-FLI1-regulated genes by shRNA depletion of EWS-FLI1in the same cell line. Duplicate knock down experiments were carried out and compared to duplicate scrambled shRNA controls. This signature was used to interrogate the effects in duplicate experiments of low- and high-dose actinomycin D treatment in A673 cells as compared to DMSO and untreated controls (2 each).
2013-08-26 | E-GEOD-45414 | biostudies-arrayexpress
Project description:Fusion of the EWS gene to FLI1 produces a fusion oncoprotein that drives an aberrant gene expression program responsible for the development of Ewing sarcoma. We used a homogenous proximity assay to screen for compounds that disrupt the binding of EWS-FLI1 to its cognate DNA targets. A number of DNA-binding chemotherapeutic agents were found to non-specifically disrupt protein binding to DNA. In contrast, actinomycin D was found to preferentially disrupt EWS-FLI1 binding by comparison to p53 binding to their respective cognate DNA targets in vitro. In cell-based assays, low concentrations of actinomycin preferentially blocked EWS-FLI1 binding to chromatin, and disrupted EWS-FLI1-mediated gene expression. Higher concentrations of actinomycin globally repressed transcription. These results demonstrate that actinomycin preferentially disrupts EWS-FLI1 binding to DNA at selected concentrations. Although the window between this preferential effect and global suppression is too narrow to exploit in a therapeutic manner, these results suggest that base-preferences may be exploited to find DNA-binding compounds that preferentially disrupt subclasses of transcription factors.
2013-08-26 | GSE45414 | GEO
Project description:EWS-FLI1, a multi-functional fusion oncogene, is exclusively detectable in Ewing sarcomas. However, previous studies reported that a subset of osteosarcomas also harbor EWS-ETS family fusion, suggesting that the fusion gene may be involved in the development of a particular type of osteosarcomas. Here using the doxycycline inducible EWS-FLI1 system, we established an EWS-FLI1-dependent osteosarcoma model from murine bone marrow stromal cells. We revealed that the withdrawal of EWS-FLI1 expression enhances the osteogenic differentiation of sarcoma cells, leading to mature bone formation. Taking advantage of induced pluripotent stem cell (iPSC) technology, we also showed that the sarcoma-derived iPSCs with cancer-related genetic abnormalities exhibited the impaired differentiation program of osteogenic lineage irrespective of the EWS-FLI1 expression. Finally, we demonstrated that EWS-FLI1 contributed to in vitro sarcoma development from the sarcoma-iPSCs after osteogenic differentiation. These findings demonstrated that modulating cellular differentiation is fundamental principle of the EWS-FLI1-induced osteosarcoma development. Furthermore, the in vitro cancer model using sarcoma-iPSCs should provide a novel platform for dissecting relationship between cancer genome and cellular differentiation. Chip-seq in mouse EWS-FLI1-induced osteosarcoma cell lines (SCOS#2 )
2016-03-01 | E-GEOD-72897 | biostudies-arrayexpress
Project description:EWS-FLI1, a multi-functional fusion oncogene, is exclusively detectable in Ewing sarcomas. However, previous studies reported that a subset of osteosarcomas also harbor EWS-ETS family fusion, suggesting that the fusion gene may be involved in the development of a particular type of osteosarcomas. Here using the doxycycline inducible EWS-FLI1 system, we established an EWS-FLI1-dependent osteosarcoma model from murine bone marrow stromal cells. We revealed that the withdrawal of EWS-FLI1 expression enhances the osteogenic differentiation of sarcoma cells, leading to mature bone formation. Taking advantage of induced pluripotent stem cell (iPSC) technology, we also showed that the sarcoma-derived iPSCs with cancer-related genetic abnormalities exhibited the impaired differentiation program of osteogenic lineage irrespective of the EWS-FLI1 expression. Finally, we demonstrated that EWS-FLI1 contributed to in vitro sarcoma development from the sarcoma-iPSCs after osteogenic differentiation. These findings demonstrated that modulating cellular differentiation is fundamental principle of the EWS-FLI1-induced osteosarcoma development. Furthermore, the in vitro cancer model using sarcoma-iPSCs should provide a novel platform for dissecting relationship between cancer genome and cellular differentiation. Microarray in mouse EWS-FLI1-induced osteosarcoma cell lines(SCOS#2 and SCOS#12) and sarcoma(SCOS#2)-derived iPSCs. Total 6 samples were analyzed. We can induce EWS-FLI1 expression by Doxycycline-inducible expression system in SCOS#2 and #12. We investigaed EWS-FLI1 activated genes (Dox ON-High) and EWS-FLI1 repressed genes (Dox OFF-High) in SCOS#2 and #12 sarcoma cell lines. Also, we investigated global gene expression pattern of sarcoma-derived iPSCs (iPSC#2-A1 and #2-B5). A link to this sample file can be found below.
2016-03-01 | E-GEOD-72704 | biostudies-arrayexpress
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
2013-07-01 | E-GEOD-27524 | biostudies-arrayexpress
Project description:EWS/ETS fusion transcription factors, most commonly EWSR1-FLI1, drive initiation and progression of Ewing sarcoma (EwS), a highly aggressive childhood cancer of bone and soft tissues. Even though direct targeting EWSR1-FLI1 is a formidable challenge, epigenetic or transcriptional modulators have been recently proved to be promising therapeutic targets for indirectly disrupting its expression and/or function. Here, we performed transcriptome and functional genomics dataset analyses, and combined with small molecule screening of EwS lines to identify novel epigenetic/transcriptional-targeted therapeutic strategies. SSRP1 and SUPT16H, two subunits of the Facilitates Chromatin Transcription (FACT) complex, are both found to be EWSR1-FLI1-induced essential oncogenes in EwS. The FACT-targeted drug CBL0137 exhibits potent therapeutic efficacy against multiple EwS preclinical models in vitro and in vivo. Mechanistically, the FACT complex and EWS-FLI1 form oncogenic positive feedback loop via mutual transcriptional regulation and activation, and cooperatively promote cell cycle/DNA replication process and IGF1R-PI3K-AKT-mTOR pathway to drive EwS oncogenesis. The FACT inhibitor drug CBL0137 effectively targets the EWSR1-FLI1-FACT circuit, resulting in transcriptional disruption of EWS-FLI1, SSRP1 and their downstream effector oncogenic signatures. Our study illustrates a crucial role of the FACT complex in facilitating the expression and function of EWSR1-FLI1 and demonstrates FACT inhibition as a novel therapeutic strategy against EwS via indirect targeting the oncogenic fusion TF, providing preclinical support for adding EwS to CBL0137’s future clinical trials.
2022-12-31 | GSE195802 | GEO
Project description:EWS/ETS fusion transcription factors, most commonly EWSR1-FLI1, drive initiation and progression of Ewing sarcoma (EwS), a highly aggressive childhood cancer of bone and soft tissues. Even though direct targeting EWSR1-FLI1 is a formidable challenge, epigenetic or transcriptional modulators have been recently proved to be promising therapeutic targets for indirectly disrupting its expression and/or function. Here, we performed transcriptome and functional genomics dataset analyses, and combined with small molecule screening of EwS lines to identify novel epigenetic/transcriptional-targeted therapeutic strategies. SSRP1 and SUPT16H, two subunits of the Facilitates Chromatin Transcription (FACT) complex, are both found to be EWSR1-FLI1-induced essential oncogenes in EwS. The FACT-targeted drug CBL0137 exhibits potent therapeutic efficacy against multiple EwS preclinical models in vitro and in vivo. Mechanistically, the FACT complex and EWS-FLI1 form oncogenic positive feedback loop via mutual transcriptional regulation and activation, and cooperatively promote cell cycle/DNA replication process and IGF1R-PI3K-AKT-mTOR pathway to drive EwS oncogenesis. The FACT inhibitor drug CBL0137 effectively targets the EWSR1-FLI1-FACT circuit, resulting in transcriptional disruption of EWS-FLI1, SSRP1 and their downstream effector oncogenic signatures. Our study illustrates a crucial role of the FACT complex in facilitating the expression and function of EWSR1-FLI1 and demonstrates FACT inhibition as a novel therapeutic strategy against EwS via indirect targeting the oncogenic fusion TF, providing preclinical support for adding EwS to CBL0137’s future clinical trials.
2022-12-31 | GSE195804 | GEO