Similar Datasets
Project description:Bromodomain-containing protein 9 (BRD9) is a recently identified subunit of SWI/SNF(BAF) chromatin remodeling complexes, yet its function is poorly understood. Here, using a genome-wide CRISPR-Cas9 screen, we show that BRD9 is a specific vulnerability in pediatric malignant rhabdoid tumors (RTs), which are driven by inactivation of the SMARCB1 subunit of SWI/SNF. We find that BRD9 exists in a unique SWI/SNF sub-complex that lacks SMARCB1, which has been considered a core subunit. While SMARCB1-containing SWI/SNF complexes are bound preferentially at enhancers, we show that BRD9-containing complexes exist at both promoters and enhancers. Mechanistically, we show that SMARCB1 loss causes increased BRD9 incorporation into SWI/SNF thus providing insight into BRD9 vulnerability in RTs. Underlying the dependency, while its bromodomain is dispensable, the DUF3512 domain of BRD9 is essential for SWI/SNF integrity in the absence of SMARCB1. Collectively, our results reveal a BRD9-containing SWI/SNF subcomplex is required for the survival of SMARCB1-mutant RTs.
| S-EPMC6479050 | biostudies-literature
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 | GSE120234 | 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 | GSE120233 | 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
Project description:BRD9 defines a novel SWI/SNF sub-complex and constitutes a specific vulnerability in malignant rhabdoid tumors
| PRJNA492260 | ENA
Project description:BRD9 defines a novel SWI/SNF sub-complex and constitutes a specific vulnerability in malignant rhabdoid tumors [ChIP-seq]
| PRJNA492264 | ENA
Project description:BRD9 defines a novel SWI/SNF sub-complex and constitutes a specific vulnerability in malignant rhabdoid tumors [RNA-seq]
| PRJNA492263 | ENA
Project description:BRD9 defines a novel SWI/SNF sub-complex and constitutes a specific vulnerability in malignant rhabdoid tumors [RNA-seq 2]
| PRJNA517485 | ENA
Project description:Rhabdoid sarcomas are highly malignant tumors that usually occur in young children. A key to the genesis of this tumor is the mutational loss of the BAF47 gene as well as the widespread epigenetic suppression of other key anticancer genes. The BRM gene is one such epigenetically silenced gene in Rhabdoid tumors. This gene codes for an ATPase catalytic subunit that shifts histones and opens the chromatin. We show that BRM is an epigenetically silenced gene in 10/11 Rhabdoid cell lines and in 70% of Rhabdoid tumors. Moreover, BRM can be induced by BAF47 re-expression and by Flavopiridol. By selective shRNAi knockdown of BRM, we show that BRM re-expression is necessary for growth inhibition by BAF47 re-expression or Flavopiridol application. Similar to lung cancer cell lines, we found that HDAC3, HDAC9, MEF2D and GATA3 controlled BRM silencing and that HDAC9 was overexpressed in Rhabdoid cancer cell lines. In primary BRM-deficient Rhabdoid tumors, HDAC9 was also found to be highly overexpressed. Two insertional BRM promoter polymorphisms contribute to BRM silencing, but only the -1321 polymorphism correlated with BRM silencing in Rhabdoid cell lines. To determine how these polymorphisms were tied to BRM silencing, we conducted ChIP assays and found that both HDAC9 and MEF2D bound to the BRM promoter at or near these polymorphic sites. Using BRM promoter swap experiments, we indirectly showed that both HDAC9 and MEF2D bound to these polymorphic sites. Together, these data show that the mechanism of BRM silencing contributes to the pathogenesis of Rhabdoid tumors and appears to be conserved among tumor types.
| S-EPMC4102812 | biostudies-literature
Project description:BackgroundRhabdoid tumors (RTs) arise within (atypical teratoid/rhabdoid tumor [AT/RT]) or outside the brain (extra [e]CNS-RT) and are driven mainly by inactivation of the SWItch/sucrose nonfermentable (SWI/SNF) complex subunit SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 (SMARCB1). A pathognomonic hallmark of RTs is heterogeneous multilineage differentiation, including anomalous neuronal differentiation in some eCNS-RTs. Because remodeling of the SWI/SNF complex regulates differentiation, we hypothesized that SWI/SNF Brahma-associated factors (BAF) and polybromo-associated BAF (PBAF) complex heterogeneity are related to both multilineage differentiation and clinical outcome.MethodsWe performed an integrated analysis of SWI/SNF complex alterations in the developing kidney and cerebellum (most common regions of RT origin) in comparison to eCNS-RT (n = 14) and AT/RT (n = 25) tumors. RT samples were interrogated using immunohistochemistry, DNA methylation, and gene expression analyses.ResultsThe SWI/SNF BAF paralogs actin-like protein (ACTL)6A and ACTL6B were expressed in a mutually exclusive manner in the developing cerebellum and kidney. In contrast, a subset of eCNS-RTs lost mutual exclusivity and coexpressed both subunits. These tumors showed aberrant DNA methylation of genes that regulate neuronal and renal development and demonstrated immunohistochemical evidence of neuronal differentiation. In addition, low expression of the PBAF subunit polybromo-1 (PBRM1) identified a group of AT/RTs in younger children with better overall prognosis. PBRM1-low AT/RT and eCNS-RTs showed altered DNA methylation and gene expression in immune-related genes. PBRM1 knockdown resulted in lowering immunosuppressive cytokines, and PBRM1 levels in tumor samples showed an inverse relationship with cluster of differentiation (CD)8 cytotoxic T-cell infiltration.ConclusionsHeterogeneity in SWI/SNF BAF (ACTL6A/ACTL6B) and PBAF (PBRM1) subunits is related to histogenesis, contributes to the immune microenvironment and prognosis in RTs, and may inform opportunities to develop immunotherapies.
| S-EPMC7283032 | biostudies-literature