SMARCA4 loss and mutated β-catenin induce proliferative lesions in the murine embryonic cerebellum
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PROVIDER: PRJNA1004337 | ENA |
REPOSITORIES: ENA
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Project description:Almost all medulloblastomas (MB) of the Wingless/Int-1 (WNT) subgroup are characterized by hotspot mutations in CTNNB1, and mouse models have convincingly demonstrated the tumor-initiating role of these mutations. Additional alterations in SMARCA4 are detected in around 20 % of WNT MB but their functional role is mostly unknown. We therefore amended previously described Blbp-cre::Ctnnb1(ex3)fl/wt mice by the introduction of a floxed Smarca4 allele. In contrast to existing literature, even mutated β-catenin on its own in our Blbp-cre::Ctnnb1(ex3)fl/wt mice induced severe developmental phenotypes including a thinned cerebral cortex, hydrocephalus, missing cerebellar layering, and non-proliferative cell accumulations in brain stem and cerebellum. An additional homozygous loss of SMARCA4 even resulted in prenatal death for most mice. Interestingly, Blbp-cre::Ctnnb1(ex3)fl/wt::Smarca4fl/fl mutants developed big proliferative lesions in the cerebellum that evolved from E13.5 to E16.5. Histological and molecular analysis of these lesions by DNA methylation analysis and single-cell RNA sequencing suggest an origin in early undifferentiated SOX2-positive cerebellar progenitors. Furthermore, upregulation of WNT signaling and altered actin/cytoskeleton organization and neuronal differentiation were evident in mutant cells. In vitro, cells harboring alterations in both Ctnnb1 and Smarca4 were negatively selected and did not show tumorigenic potential after transplantation in adult recipient mice. However, mutant cells displayed increased proliferation compared to controls in cerebellar explant culture, indicating an important role of the embryonic microenvironment in the development of lesions. Altogether, these results represent an important first step in unravelling tumorigenic mechanisms induced by aberrant WNT signaling and a SMARCA4 deficiency.
2024-04-17 | GSE240627 | GEO
Project description:Almost all medulloblastomas (MB) of the Wingless/Int-1 (WNT) type are characterized by hotspot mutations in CTNNB1, and mouse models have convincingly demonstrated the tumor-initiating role of these mutations. Additional alterations in SMARCA4 are detected in around 20% of WNT MB, but their functional role is mostly unknown. We therefore amended previously described Blbp cre::Ctnnb1(ex3)fl/wt mice by the introduction of a floxed Smarca4 allele. Unexpectedly, mutated β-catenin on its own induced severe developmental phenotypes in Blbp cre::Ctnnb1(ex3)fl/wt mice in our hands, including a thinned cerebral cortex, hydrocephalus, missing cerebellar layering, and non-proliferative cell accumulations in the brain stem and cerebellum. An additional loss of SMARCA4 even resulted in prenatal death for most mice. Respective Blbp cre::Ctnnb1(ex3)fl/wt::Smarca4fl/fl mutants developed large proliferative lesions in the cerebellum evolving from E13.5 to E16.5. Histological and molecular analysis of these lesions by DNA methylation profiling and single-cell RNA sequencing suggested an origin in early undifferentiated SOX2-positive cerebellar progenitors. Furthermore, upregulated WNT signaling, altered actin/cytoskeleton organization, and reduced neuronal differentiation were evident in mutant cells. In vitro, cells harboring alterations in both Ctnnb1 and Smarca4 were negatively selected and did not show tumorigenic potential after transplantation in adult recipient mice. However, in cerebellar explant cultures, mutant cells displayed significantly increased proliferation, suggesting an important role of the embryonic microenvironment in the development of lesions. Altogether, these results represent an important first step towards the unravelling of tumorigenic mechanisms induced by aberrant WNT signaling and SMARCA4 deficiency.
2024-04-17 | GSE241018 | GEO
Project description:SMARCA4 loss and mutated β-catenin induce proliferative lesions in the murine embryonic cerebellum [scRNA-seq]
| PRJNA1006057 | ENA
Project description:High-throughput gene expression profilng of SMARCA4-mutated extra-cranial rhabdoid tumours (ECRT-SMARCA4), SMARCB1-mutated ECRT, ATRT and SCCOHT tumours by RNA sequencing
| PRJNA734266 | ENA
Project description:SMARCA4 gene is mutated in a subset of Group 3 medulloblastomas. ShRNA mediated downregulation of SMARCA4 expression in three Group 3 medulloblastoma cell lines upregulated the expression of myogenic/muscle differentiation related genes as studied by the transcriptome analysis.
2023-03-10 | GSE198463 | GEO
Project description:Purpose: Molecular characterization of ECRT-SMARCA4 tumours and their place within the constellation of ECRT-SMARCB1, ATRT and SCCOHT Methods: Total RNA was obtained from 72 fresh-frozen tumour samples using the Qiagen RNAeasy kit (Qiagen, Venlo, Netherlands), according to the manufacturer’s procedure. Barcode Illumina compatible libraries were generated from 750 ng of total RNA for each sample using the TruSeq Stranded mRNA Library Preparation Kit (Illumina). Libraries were sequenced using the Illumina HiSeq 2500 platform. RNA-seq data pre-processing was performed using an in-house pipeline developed at the Curie Institute Bioinformatics Core Facility. Read mapping and counting were performed using STAR, version 2.5.3) and the hg19 version of the human reference genome. Results: Dimensionality reduction and hierarchical clustering algorithms applied to the transcriptomics dataset show that ECRT-SMARCA4 display molecular features intermediate between SCCOHT and ECRTS-MARCB1.
2021-06-02 | GSE175891 | GEO
Project description:β-catenin drives distinct transcriptional networks in proliferative and non-proliferative cardiomyocytes
| PRJNA632627 | ENA
Project description:The mammalian SWI/SNF helicase SMARCA4 is frequently mutated in cancer and inactivation results in a cellular dependence on its paralog, SMARCA2, thus making SMARCA2 an attractive synthetic lethal target. However, published data indicates that achieving a high degree of SMARCA2 selectivity is likely essential to afford an acceptable therapeutic index and this has been a considerable challenge due to the homology between paralogs. Herein we report the discovery of the first potent and selective SMARCA2 proteolysis-targeting chimera (PROTAC) molecule. Selective degradation was achieved in the absence of selective PROTAC binding and translated to potent in vitro growth inhibition and in vivo efficacy in SMARCA4 mutant models, compared to wild type models. Global ubiquitin mapping and proteome profiling revealed no unexpected off-target degradation. Our study thus highlights the ability to transform a non-selective SMARCA2-binding ligand into a selective and efficacious in vivo SMARCA2 PROTAC, providing a potential therapeutic opportunity for SMARCA4 mutant patients.
2022-09-22 | PXD036865 | Pride
Project description:The packaging of DNA into chromatin plays an important role in transcriptional regulation and nuclear processes. Brahma related gene-1 SMARCA4 (also known as BRG1), the essential ATPase subunit of the mammalian SWI/SNF chromatin remodeling complex, uses the energy from ATP hydrolysis to disrupt nucleosomes at target regions. Although the transcriptional role of SMARCA4 at gene promoters is well-studied, less is known about its role in higher-order genome organization. SMARCA4 knockdown in human mammary epithelial MCF-10A cells resulted in 176 up-regulated genes, including many related to lipid and calcium metabolism, and 1292 down-regulated genes, some of which encode extracellular matrix (ECM) components that can exert mechanical forces and affect nuclear structure. ChIP-seq analysis of SMARCA4 localization and SMARCA4-bound super-enhancers demonstrated extensive binding at intergenic regions. Furthermore, Hi-C analysis showed extensive SMARCA4-mediated alterations in higher-order genome organization at multiple resolutions. First, SMARCA4 knockdown resulted in clustering of intra- and inter- sub-telomeric regions, demonstrating a novel role for SMARCA4 in telomere organization. SMARCA4 binding was enriched at TAD (Topologically Associating Domain) boundaries, and SMARCA4 knockdown resulted in weakening of TAD boundary strength. Taken together, these findings provide a dynamic view of SMARCA4-dependent changes in higher-order chromatin organization and gene expression, identifying SMARCA4 as a novel component of chromatin organization. Hi-C and RNA-seq experiments were conducted in MCF-10A shSCRAM and shSMARCA4 cells. SMARCA4 ChIP-seq was conducted in wildtype MCF-10A cells.
2016-06-02 | E-GEOD-74716 | biostudies-arrayexpress
Project description:Purpose: The purpose of this study was to develop a framework for analyzing RPE expression profiles from zebrafish eye mutants. Methods: The fish model we used was smarca4 (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a, member 4), a retinal dystrophic mutant that the retinal phenotype and expression profiles were previously characterized. Histological and Affymetrix GeneChip analyses were conducted to define the RPE defects and underlying differential expression respectively. Results: Histological analysis indicates that smarca4 RPE was formed but its differentiation was abnormal. In particular, ultra-structural analysis of smarca4 RPE by transmission electron microscopy showed a number of defects in melanogenesis, suggesting that the cytoskeletal dynamics was impaired. To compare the expression profile of normal wild-type (WT) and smarca4 RPE, their retinas and RPE-attached retinas were microdissected and the gene expression values of these tissues measured by Affymetrix GeneChip analysis. The RPE expression values were then estimated from these samples using an approach previously established by us. A factorial analysis was conducted using the expression values of RPE, retinal as well as the whole-embryo samples. Specific rules (contrasts) were built using the coefficients of the resulting fitted model to select for three groups of genes: 1) Smarca4-regulated RPE genes, 2) Smarca4-regulated retinal genes, and 3) Smarca4-regulated RPE genes that are not differentially expressed in the retina. The latter group consists of 39 genes that are highly related to cytoskeletal dynamics, melanogenesis, paracrine and intracellular signal transduction. Conclusions: Our analytical framework can potentially identify genes in zebrafish mutants that both retina and RPE are affected by the underlying mutation. The gene expression levels of three independent replicates of WT whole embryos (WA52), WT retinas (WR52), WT RPE-attached retinas (WRR52), smarca4/yng retinas (YR52), smarca4 RPE-attached retinas (YRR52) and smarca4 whole embryos (YA52) were measured by Affymetrix Zebrafish Whole Genome Arrays. All samples were collected at 52 hpf. The probe-level data of these sample groups were background adjusted, normalized and summarized by a robust multiarray average (RMA) algorithm. RPE expression values were estimated from the comparison between the retinal and RPE-attached retinal samples of the same genotype based on a method we previously developed (Leung et al., Invest Ophthalmol Vis Sci. 2007; 48:881). Then, a 3x2 factorial design was used to analyze the expression values of three kinds of tissue (T): whole embryo, retina and RPE in two kinds of mutation (M) background: WT and smarca4. Using the coefficients from the fitted models, contrasts were built to identify candidate genes that fulfilled specific criteria. The false discovery rate (FDR) q-value cutoff for a contrast was 0.001. Several contrasts were ultimately combined to allow for selection of genes that were regulated by Smarca4 in the retina and RPE. These include 1) Smarca4-regulated RPE genes, 2) Smarca4-regulated retinal genes, and 3) Smarca4-regulated RPE genes that are not differentially expressed in the retina.
2014-01-03 | E-GEOD-50241 | biostudies-arrayexpress