BET bromodomain dependency in EWS/ETS driven Ewing Sarcoma
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ABSTRACT:
PROVIDER: PRJNA453371 | ENA |
REPOSITORIES: ENA
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Project description:The pathognomonic EWS/ETS fusion transcription factors drive Ewing sarcoma (EWS) by orchestrating an oncogenic transcription program. Therapeutic targeting of EWS/ETS has not been successful; therefore identifying mediators of the EWS/ETS function could offer new therapeutic targets. Here we describe the dependency of chromatin reader BET bromodomain proteins in EWS/ETS driven transcription and investigate the potential of BET inhibitors in treating this lethal cancer. Similar to EWS/ETS fusions, knockdown of BET proteins BRD2/3/4 severely impaired the oncogenic phenotype of EWS cells. Notably, EWS/FLI1 and EWS/ERG was found to be in a transcriptional complex consisting of BRD4. RNA-Seq analysis upon BRD4 knockdown or its pharmacologic inhibition by the BET inhibitor JQ1 revealed an attenuated EWS/ETS transcriptional signature. In contrast to other reports, JQ1 reduced proliferation, and induced apoptosis through MYC-independent mechanism without affecting EWS/ETS protein levels, which was further confirmed by depleting BET proteins using PROTAC-BET degrader (BETd). Interestingly, polycomb repressive complex 2 (PRC2) associated factor PHF19 was downregulated by JQ1/BETd or BRD4 knockdown in multiple EWS cells. ChIP-seq analysis revealed occupancy of EWS/FLI1 at a distal regulatory element of PHF19 and its subsequent knockdown resulted in downregulation of PHF19 expression. Furthermore, deletion of PHF19 by CRISPR-Cas9 system lead to a decreased tumorigenic phenotype and increased sensitivity to JQ1. Importantly, PHF19 expression was associated with worse prognosis of Ewing sarcoma patients. In vivo, JQ1 demonstrated anti-tumor efficacy in multiple mouse xenograft models of EWS. Together, these results indicate that EWS/ETS require BET epigenetic reader proteins for its transcriptional program including PHF19 expression, which can be mitigated by BET inhibitors. Moreover, this study provides a clear rationale for the clinical utility of BET inhibitors in treating Ewing sarcoma.
2018-06-19 | GSE113604 | GEO
Project description:Ewing sarcomas (ES) are highly malignant, osteolytic bone or soft tissue tumors, which are characterized by early metastasis into lung and bone. Genetically, ES are defined by balanced chromosomal EWS/ETS translocations, which give rise to chimeric proteins (EWS-ETS) that generate an oncogenic transcriptional program associated with altered epigenetic marks throughout the genome. By use of an inhibitor (JQ1) blocking BET bromodomain binding proteins (BRDs) we strikingly observed a strong down-regulation of the predominant EWS-ETS protein EWS/FLI1 in a dose dependent manner. Microarray analysis further revealed JQ1 treatment to block a typical ES associated expression program. The effect on this expression program could be mimicked by RNA interference with BRD3 or BRD4 expression, indicating that the EWS/FLI1 mediated expression profile is at least in part mediated via such epigenetic readers. Consequently, contact dependent and independent proliferation of different ES lines was strongly inhibited. Mechanistically, treatment of ES resulted in a partial arrest of the cell cycle as well as induction of apoptosis. Tumor development was suppressed dose dependently in a xeno-transplant model in immune deficient mice, overall indicating that ES may be susceptible to treatment with epigenetic inhibitors blocking BET bromodomain activity and the associated pathognomonic EWS-ETS transcriptional program in ES. Ewing sarcoma cell lines A673 and TC-71 were treated for 48 hours with 2 microM JQ1 or DMSO control.
2015-12-08 | E-GEOD-72673 | biostudies-arrayexpress
Project description:Ewing sarcomas (ES) are highly malignant, osteolytic bone or soft tissue tumors, which are characterized by early metastasis into lung and bone. Genetically, ES are defined by balanced chromosomal EWS/ETS translocations, which give rise to chimeric proteins (EWS-ETS) that generate an oncogenic transcriptional program associated with altered epigenetic marks throughout the genome. By use of an inhibitor (JQ1) blocking BET bromodomain binding proteins (BRDs) we strikingly observed a strong down-regulation of the predominant EWS-ETS protein EWS/FLI1 in a dose dependent manner. Microarray analysis further revealed JQ1 treatment to block a typical ES associated expression program. The effect on this expression program could be mimicked by RNA interference with BRD3 or BRD4 expression, indicating that the EWS/FLI1 mediated expression profile is at least in part mediated via such epigenetic readers. Consequently, contact dependent and independent proliferation of different ES lines was strongly inhibited. Mechanistically, treatment of ES resulted in a partial arrest of the cell cycle as well as induction of apoptosis. Tumor development was suppressed dose dependently in a xeno-transplant model in immune deficient mice, overall indicating that ES may be susceptible to treatment with epigenetic inhibitors blocking BET bromodomain activity and the associated pathognomonic EWS-ETS transcriptional program in ES.
2015-12-08 | GSE72673 | GEO
Project description:Pediatric cancers frequently harbor sentinel mutations involving transcription factors (TFs) that dysregulate normal development. A recurrent mechanism involves the ability of mutant TFs to co-opt cell lineage-specific, activating TFs to promote cancer growth. Ewing sarcoma, the second most common pediatric bone cancer, is defined by the presence of a 11;22 chromosomal translocation fusing the N-terminus of the EWS protein with the C-terminal DNA binding domain of an ETS (E26 Transformation Specific) TF family member, most commonly (85-90% of cases), FLI1. The EWS/FLI fusion exhibits the neomorphic ability to pioneer de novo enhancers at repeating 5’-GGAA-3’ motifs in the cell-of-origin, which has not been identified. To date, efforts to elucidate the key mechanisms by which EWS/FLI promotes oncogenesis have prioritized identifying the genes that are profoundly activated by EWS/FLI and highly expressed in Ewing sarcoma compared to other cancers, with particular focus on transcription factors capable of altering cell state. However, it is not known whether, globally, these genes constitute the most critical drivers of Ewing sarcoma cell growth. Here, we describe the results of an unbiased deletion screen revealing that the wild-type repressive ETS family TF, ETV6 (ETS Variant 6, or TEL), is a novel and most critical TF dependency specific to Ewing sarcoma. We demonstrate that the repressive activity of ETV6 constrains EWS/FLI gene activation at GGAA repeat enhancers to promote Ewing sarcoma cell growth.
2022-10-05 | GSE211852 | GEO
Project description:Pediatric cancers frequently harbor sentinel mutations involving transcription factors (TFs) that dysregulate normal development. A recurrent mechanism involves the ability of mutant TFs to co-opt cell lineage-specific, activating TFs to promote cancer growth. Ewing sarcoma, the second most common pediatric bone cancer, is defined by the presence of a 11;22 chromosomal translocation fusing the N-terminus of the EWS protein with the C-terminal DNA binding domain of an ETS (E26 Transformation Specific) TF family member, most commonly (85-90% of cases), FLI1. The EWS/FLI fusion exhibits the neomorphic ability to pioneer de novo enhancers at repeating 5’-GGAA-3’ motifs in the cell-of-origin, which has not been identified. To date, efforts to elucidate the key mechanisms by which EWS/FLI promotes oncogenesis have prioritized identifying the genes that are profoundly activated by EWS/FLI and highly expressed in Ewing sarcoma compared to other cancers, with particular focus on transcription factors capable of altering cell state. However, it is not known whether, globally, these genes constitute the most critical drivers of Ewing sarcoma cell growth. Here, we describe the results of an unbiased deletion screen revealing that the wild-type repressive ETS family TF, ETV6 (ETS Variant 6, or TEL), is a novel and most critical TF dependency specific to Ewing sarcoma. We demonstrate that the repressive activity of ETV6 constrains EWS/FLI gene activation at GGAA repeat enhancers to promote Ewing sarcoma cell growth.
2022-10-05 | GSE193167 | GEO
Project description:Pediatric cancers frequently harbor sentinel mutations involving transcription factors (TFs) that dysregulate normal development. A recurrent mechanism involves the ability of mutant TFs to co-opt cell lineage-specific, activating TFs to promote cancer growth. Ewing sarcoma, the second most common pediatric bone cancer, is defined by the presence of a 11;22 chromosomal translocation fusing the N-terminus of the EWS protein with the C-terminal DNA binding domain of an ETS (E26 Transformation Specific) TF family member, most commonly (85-90% of cases), FLI1. The EWS/FLI fusion exhibits the neomorphic ability to pioneer de novo enhancers at repeating 5’-GGAA-3’ motifs in the cell-of-origin, which has not been identified. To date, efforts to elucidate the key mechanisms by which EWS/FLI promotes oncogenesis have prioritized identifying the genes that are profoundly activated by EWS/FLI and highly expressed in Ewing sarcoma compared to other cancers, with particular focus on transcription factors capable of altering cell state. However, it is not known whether, globally, these genes constitute the most critical drivers of Ewing sarcoma cell growth. Here, we describe the results of an unbiased deletion screen revealing that the wild-type repressive ETS family TF, ETV6 (ETS Variant 6, or TEL), is a novel and most critical TF dependency specific to Ewing sarcoma. We demonstrate that the repressive activity of ETV6 constrains EWS/FLI gene activation at GGAA repeat enhancers to promote Ewing sarcoma cell growth.
2022-10-05 | GSE181552 | GEO
Project description:Pediatric cancers frequently harbor sentinel mutations involving transcription factors (TFs) that dysregulate normal development. A recurrent mechanism involves the ability of mutant TFs to co-opt cell lineage-specific, activating TFs to promote cancer growth. Ewing sarcoma, the second most common pediatric bone cancer, is defined by the presence of a 11;22 chromosomal translocation fusing the N-terminus of the EWS protein with the C-terminal DNA binding domain of an ETS (E26 Transformation Specific) TF family member, most commonly (85-90% of cases), FLI1. The EWS/FLI fusion exhibits the neomorphic ability to pioneer de novo enhancers at repeating 5’-GGAA-3’ motifs in the cell-of-origin, which has not been identified. To date, efforts to elucidate the key mechanisms by which EWS/FLI promotes oncogenesis have prioritized identifying the genes that are profoundly activated by EWS/FLI and highly expressed in Ewing sarcoma compared to other cancers, with particular focus on transcription factors capable of altering cell state. However, it is not known whether, globally, these genes constitute the most critical drivers of Ewing sarcoma cell growth. Here, we describe the results of an unbiased deletion screen revealing that the wild-type repressive ETS family TF, ETV6 (ETS Variant 6, or TEL), is a novel and most critical TF dependency specific to Ewing sarcoma. We demonstrate that the repressive activity of ETV6 constrains EWS/FLI gene activation at GGAA repeat enhancers to promote Ewing sarcoma cell growth.
2022-10-05 | GSE181551 | GEO
Project description:Pediatric cancers frequently harbor sentinel mutations involving transcription factors (TFs) that dysregulate normal development. A recurrent mechanism involves the ability of mutant TFs to co-opt cell lineage-specific, activating TFs to promote cancer growth. Ewing sarcoma, the second most common pediatric bone cancer, is defined by the presence of a 11;22 chromosomal translocation fusing the N-terminus of the EWS protein with the C-terminal DNA binding domain of an ETS (E26 Transformation Specific) TF family member, most commonly (85-90% of cases), FLI1. The EWS/FLI fusion exhibits the neomorphic ability to pioneer de novo enhancers at repeating 5’-GGAA-3’ motifs in the cell-of-origin, which has not been identified. To date, efforts to elucidate the key mechanisms by which EWS/FLI promotes oncogenesis have prioritized identifying the genes that are profoundly activated by EWS/FLI and highly expressed in Ewing sarcoma compared to other cancers, with particular focus on transcription factors capable of altering cell state. However, it is not known whether, globally, these genes constitute the most critical drivers of Ewing sarcoma cell growth. Here, we describe the results of an unbiased deletion screen revealing that the wild-type repressive ETS family TF, ETV6 (ETS Variant 6, or TEL), is a novel and most critical TF dependency specific to Ewing sarcoma. We demonstrate that the repressive activity of ETV6 constrains EWS/FLI gene activation at GGAA repeat enhancers to promote Ewing sarcoma cell growth.
2022-10-05 | GSE181553 | GEO
Project description:Pediatric cancers frequently harbor sentinel mutations involving transcription factors (TFs) that dysregulate normal development. A recurrent mechanism involves the ability of mutant TFs to co-opt cell lineage-specific, activating TFs to promote cancer growth. Ewing sarcoma, the second most common pediatric bone cancer, is defined by the presence of a 11;22 chromosomal translocation fusing the N-terminus of the EWS protein with the C-terminal DNA binding domain of an ETS (E26 Transformation Specific) TF family member, most commonly (85-90% of cases), FLI1. The EWS/FLI fusion exhibits the neomorphic ability to pioneer de novo enhancers at repeating 5’-GGAA-3’ motifs in the cell-of-origin, which has not been identified. To date, efforts to elucidate the key mechanisms by which EWS/FLI promotes oncogenesis have prioritized identifying the genes that are profoundly activated by EWS/FLI and highly expressed in Ewing sarcoma compared to other cancers, with particular focus on transcription factors capable of altering cell state. However, it is not known whether, globally, these genes constitute the most critical drivers of Ewing sarcoma cell growth. Here, we describe the results of an unbiased deletion screen revealing that the wild-type repressive ETS family TF, ETV6 (ETS Variant 6, or TEL), is a novel and most critical TF dependency specific to Ewing sarcoma. We demonstrate that the repressive activity of ETV6 constrains EWS/FLI gene activation at GGAA repeat enhancers to promote Ewing sarcoma cell growth.
2022-10-05 | GSE211853 | GEO
Project description:The cellular origin of Ewing tumor (ET), a tumor of bone or soft tissues characterized by specific fusions between EWS and ETS genes, is highly debated. Through gene expression analysis comparing ETs with a variety of normal tissues, we show that the profiles of different EWS-FLI1-silenced Ewing cell lines converge toward that of mesenchymal stem cells (MSC). Moreover, upon EWS-FLI1 silencing, two different Ewing cell lines can differentiate along the adipogenic lineage when incubated in appropriate differentiation cocktails. In addition, Ewing cells can also differentiate along the osteogenic lineage upon long-term inhibition of EWS-FLI1. These in silico and experimental data strongly suggest that the inhibition of EWS-FLI1 may allow Ewing cells to recover the phenotype of their MSC progenitor. Experiment Overall Design: Ewing tumors and EWS-FLI-1 inhibited cell lines were profiled on Affymetrix U133A (GPL96) arrays.
2008-06-15 | E-GEOD-7007 | biostudies-arrayexpress