SWI/SNF inhibition leads to epigenetic reprogramming in rhabdoid tumor [ATAC-seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE137397 | GEO | 2020/11/16
REPOSITORIES: GEO
Similar Datasets
Project description:Rhabdoid tumor is a pediatric cancer characterized by the biallelic inactivation of SMARCB1, a subunit of the SWI/SNF chromatin remodeling complex. SMARCB1 inactivation leads to SWI/SNF redistribution to favor a proliferative dedifferentiated cellular state. Although this deletion is the known oncogenic driver, SWI/SNF therapeutic targeting remains a challenge. Here we show mithramycin and a second-generation analogue EC-8042 are effective in this tumor type. Mithramycin evicts SWI/SNF from chromatin triggering a cellular response characterized by chromatin compartment remodeling and promoter reprogramming. These effects lead to differentiation and marked xenograft tumor regressions in vivo. This study provides a therapeutic candidate for rhabdoid tumor and an approach that may be applicable to the more than 20% of cancers characterized by mutated SWI/SNF.
2020-11-16 | GSE137399 | GEO
Project description:Rhabdoid tumor is a pediatric cancer characterized by the biallelic inactivation of SMARCB1, a subunit of the SWI/SNF chromatin remodeling complex. SMARCB1 inactivation leads to SWI/SNF redistribution to favor a proliferative dedifferentiated cellular state. Although this deletion is the known oncogenic driver, SWI/SNF therapeutic targeting remains a challenge. Here we show mithramycin and a second-generation analogue EC-8042 are effective in this tumor type. Mithramycin evicts SWI/SNF from chromatin triggering a cellular response characterized by chromatin compartment remodeling and promoter reprogramming. These effects lead to differentiation and marked xenograft tumor regressions in vivo. This study provides a therapeutic candidate for rhabdoid tumor and an approach that may be applicable to the more than 20% of cancers characterized by mutated SWI/SNF.
2020-11-16 | GSE137403 | GEO
Project description:While oncogenes can potentially be inhibited with small molecules, the loss of tumor suppressors is more common and is problematic because the tumor suppressor proteins are no longer present to be targeted. Notable examples include SMARCB1-mutant cancers, which are highly lethal malignancies driven by the inactivation of a subunit of SWI/SNF chromatin remodeling complexes. To generate mechanistic insight into the consequences of SMARCB1 mutation and to identify vulnerabilities, we contributed 14 SMARCB1-mutant cell lines to a near genome-wide CRISPR screen as part of the Cancer Dependency Map Project1-3. Here, we report that the little-studied gene DDB1-CUL4 Associated Factor 5 (DCAF5) is required for the survival of SMARCB1-mutant cancers. We show that DCAF5 serves a quality control function for SWI/SNF complexes and promotes degradation of incompletely assembled SWI/SNF complexes in the absence of SMARCB1. Upon depletion of DCAF5, SMARCB1-deficient SWI/SNF complexes re-accumulate, bind to target loci, and restore SWI/SNF-mediated gene expression to levels sufficient to reverse the cancer state, including in vivo. Consequently, cancer results not from the loss of SMARCB1 function per se but rather from DCAF5-mediated degradation of SWI/SNF complexes. These data indicate that therapeutic targeting of ubiquitin-mediated quality control factors may effectively reverse the malignant state of some cancers driven by disruption of tumor suppressor complexes.
2024-01-21 | PXD046276 | Pride
Project description:While oncogenes can potentially be inhibited with small molecules, the loss of tumor suppressors is more common and is problematic because the tumor suppressor proteins are no longer present to be targeted. Notable examples include SMARCB1-mutant cancers, which are highly lethal malignancies driven by the inactivation of a subunit of SWI/SNF chromatin remodeling complexes. To generate mechanistic insight into the consequences of SMARCB1 mutation and to identify vulnerabilities, we contributed 14 SMARCB1-mutant cell lines to a near genome-wide CRISPR screen as part of the Cancer Dependency Map Project1-3. Here, we report that the little-studied gene DDB1-CUL4 Associated Factor 5 (DCAF5) is required for the survival of SMARCB1-mutant cancers. We show that DCAF5 serves a quality control function for SWI/SNF complexes and promotes degradation of incompletely assembled SWI/SNF complexes in the absence of SMARCB1. Upon depletion of DCAF5, SMARCB1-deficient SWI/SNF complexes re-accumulate, bind to target loci, and restore SWI/SNF-mediated gene expression to levels sufficient to reverse the cancer state, including in vivo. Consequently, cancer results not from the loss of SMARCB1 function per se but rather from DCAF5-mediated degradation of SWI/SNF complexes. These data indicate that therapeutic targeting of ubiquitin-mediated quality control factors may effectively reverse the malignant state of some cancers driven by disruption of tumor suppressor complexes.
2024-01-21 | PXD046273 | Pride
Project description:While oncogenes can potentially be inhibited with small molecules, the loss of tumor suppressors is more common and is problematic because the tumor suppressor proteins are no longer present to be targeted. Notable examples include SMARCB1-mutant cancers, which are highly lethal malignancies driven by the inactivation of a subunit of SWI/SNF chromatin remodeling complexes. To generate mechanistic insight into the consequences of SMARCB1 mutation and to identify vulnerabilities, we contributed 14 SMARCB1-mutant cell lines to a near genome-wide CRISPR screen as part of the Cancer Dependency Map Project1-3. Here, we report that the little-studied gene DDB1-CUL4 Associated Factor 5 (DCAF5) is required for the survival of SMARCB1-mutant cancers. We show that DCAF5 serves a quality control function for SWI/SNF complexes and promotes degradation of incompletely assembled SWI/SNF complexes in the absence of SMARCB1. Upon depletion of DCAF5, SMARCB1-deficient SWI/SNF complexes re-accumulate, bind to target loci, and restore SWI/SNF-mediated gene expression to levels sufficient to reverse the cancer state, including in vivo. Consequently, cancer results not from the loss of SMARCB1 function per se but rather from DCAF5-mediated degradation of SWI/SNF complexes. These data indicate that therapeutic targeting of ubiquitin-mediated quality control factors may effectively reverse the malignant state of some cancers driven by disruption of tumor suppressor complexes.
2024-01-21 | PXD046275 | Pride
Project description:SMARCB1 (SNF5/INI1/BAF47), a core subunit of the SWI/SNF (BAF) chromatin remodeling complex, is inactivated in nearly all pediatric rhabdoid tumors. These aggressive cancers are among the most genomically stable, suggesting an epigenetic mechanism by which SMARCB1 loss drives transformation. Here, we show that despite indistinguishable mutational landscapes, human RTs show distinct enhancer H3K27ac signatures, which reveal remnants of differentiation programs. We show that SMARCB1 is required for the integrity of SWI/SNF complexes and that its loss alters enhancer targeting markedly impairing SWI/SNF binding to typical enhancers, particularly those required for differentiation, while maintaining SWI/SNF binding at super-enhancers. We show that these retained super-enhancers are essential for rhabdoid tumor survival, including some that are shared across all subtypes, such as SPRY1, and other lineage-specific super-enhancers like SOX2 in brain-derived RTs. Taken together, our findings reveal a novel chromatin-based epigenetic mechanism underlying the tumor suppressive activity of SMARCB1.
2016-11-21 | GSE71505 | GEO
Project description:SMARCB1 (SNF5/INI1/BAF47), a core subunit of the SWI/SNF (BAF) chromatin remodeling complex, is inactivated in nearly all pediatric rhabdoid tumors. These aggressive cancers are among the most genomically stable, suggesting an epigenetic mechanism by which SMARCB1 loss drives transformation. Here, we show that despite indistinguishable mutational landscapes, human RTs show distinct enhancer H3K27ac signatures, which reveal remnants of differentiation programs. We show that SMARCB1 is required for the integrity of SWI/SNF complexes and that its loss alters enhancer targeting markedly impairing SWI/SNF binding to typical enhancers, particularly those required for differentiation, while maintaining SWI/SNF binding at super-enhancers. We show that these retained super-enhancers are essential for rhabdoid tumor survival, including some that are shared across all subtypes, such as SPRY1, and other lineage-specific super-enhancers like SOX2 in brain-derived RTs. Taken together, our findings reveal a novel chromatin-based epigenetic mechanism underlying the tumor suppressive activity of SMARCB1.
2016-11-21 | GSE71504 | GEO
Project description:SMARCB1 (SNF5/INI1/BAF47), a core subunit of the SWI/SNF (BAF) chromatin remodeling complex, is inactivated in nearly all pediatric rhabdoid tumors. These aggressive cancers are among the most genomically stable, suggesting an epigenetic mechanism by which SMARCB1 loss drives transformation. Here, we show that despite indistinguishable mutational landscapes, human RTs show distinct enhancer H3K27ac signatures, which reveal remnants of differentiation programs. We show that SMARCB1 is required for the integrity of SWI/SNF complexes and that its loss alters enhancer targeting markedly impairing SWI/SNF binding to typical enhancers, particularly those required for differentiation, while maintaining SWI/SNF binding at super-enhancers. We show that these retained super-enhancers are essential for rhabdoid tumor survival, including some that are shared across all subtypes, such as SPRY1, and other lineage-specific super-enhancers like SOX2 in brain-derived RTs. Taken together, our findings reveal a novel chromatin-based epigenetic mechanism underlying the tumor suppressive activity of SMARCB1.
2016-11-21 | GSE71503 | GEO
Project description:SMARCB1 (SNF5/INI1/BAF47), a core subunit of the SWI/SNF (BAF) chromatin remodeling complex, is inactivated in nearly all pediatric rhabdoid tumors. These aggressive cancers are among the most genomically stable, suggesting an epigenetic mechanism by which SMARCB1 loss drives transformation. Here, we show that despite indistinguishable mutational landscapes, human RTs show distinct enhancer H3K27ac signatures, which reveal remnants of differentiation programs. We show that SMARCB1 is required for the integrity of SWI/SNF complexes and that its loss alters enhancer targeting markedly impairing SWI/SNF binding to typical enhancers, particularly those required for differentiation, while maintaining SWI/SNF binding at super-enhancers. We show that these retained super-enhancers are essential for rhabdoid tumor survival, including some that are shared across all subtypes, such as SPRY1, and other lineage-specific super-enhancers like SOX2 in brain-derived RTs. Taken together, our findings reveal a novel chromatin-based epigenetic mechanism underlying the tumor suppressive activity of SMARCB1.
2016-11-21 | GSE71502 | GEO
Project description:Bromodomain-containing protein 9 (BRD9) was recently identified to be associated with the chromatin remodeling SWI/SNF(BAF) complex, yet its function within the complex has remained unclear. Here, using genome-scale CRISPR-Cas9 screens, we found that BRD9 constitutes a specific vulnerability in highly malignant pediatric rhabdoid tumors, which are driven by inactivating mutations of SMARCB1 subunit of SWI/SNF complexes. Surprisingly, we found that BRD9 does not belong to the previously identified BAF or PBAF complexes, but instead is found exclusively in a novel of SWI/SNF sub-complex. We show that BRD9-containing complexes lack SMARCB1, which had previously been considered a core subunit present in all SWI/SNF variants. We recently demonstrated that both SMARCB1-containing and ARID1A-containing SWI/SNF complexes preferentially function at enhancers, but here we show that BRD9-containing complexes are located at active promoters as well as enhancers. We show that loss of SMARCB1, as observed in rhabdoid tumors, results in increased BRD9 interaction with SWI/SNF core subunit SMARCC1, consistent with competition between SMARCB1 and BRD9 in the formation of SWI/SNF complexes. Underlying the dependency, we demonstrate that BRD9, via its DUF3512 domain, is essential for maintaining the integrity of its sub-complex, which predominates in the absence of SMARCB1. Taken together, our results reveal a BRD9-containing SWI/SNF subcomplex which is required for the survival of SMARCB1-mutant rhabdoid tumors.
2019-03-14 | GSE125775 | GEO