MYC overexpression and SMARCA4 loss cooperate to drive medulloblastoma formation in mice
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PROVIDER: PRJNA988041 | ENA |
REPOSITORIES: ENA
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Project description:Group 3 medulloblastoma is one of the most aggressive types of childhood brain tumors. Roughly 30% of cases carry genetic alterations in MYC, SMARCA4, or both genes combined. While overexpression of MYC has previously been shown to drive medulloblastoma formation in mice, the functional significance of SMARCA4 mutations and their suitability as a therapeutic target remain largely unclear. To address this issue, we combined overexpression of MYC with a loss of SMARCA4 in granule cell precursors. Both alterations did not increase proliferation of granule cell precursors in vitro. However, combined MYC overexpression and SMARCA4 loss successfully induced tumor formation in vivo after orthotopic transplantation in recipient mice. Resulting tumors displayed anaplastic histology and exclusively consisted of SMARCA4 negative cells although a mixture of recombined and non-recombined cells was injected. These observations provide first evidence for a tumor-promoting role of a SMARCA4 deficiency in the development of medulloblastoma. In comparing the transcriptome of tumors to the cells of origin and an established Sonic Hedgehog medulloblastoma model, we gathered first hints on deregulated gene expression that could be specifically involved in SMARCA4/MYC driven tumorigenesis. Finally, an integration of RNA sequencing and DNA methylation data of murine tumors with human samples revealed a high resemblance to human Group 3 medulloblastoma on the molecular level. Altogether, the development of SMARCA4-deficient medulloblastomas in mice paves the way to deciphering the role of frequently occurring SMARCA4 alterations in Group 3 medulloblastoma with the perspective to explore targeted therapeutic options.
2023-09-26 | GSE235924 | GEO
Project description:Group 3 medulloblastoma is one of the most aggressive types of childhood brain tumors. Roughly 30% of cases carry genetic alterations in MYC, SMARCA4, or both genes combined. While overexpression of MYC has previously been shown to drive medulloblastoma formation in mice, the functional significance of SMARCA4 mutations and their suitability as a therapeutic target remain largely unclear. To address this issue, we combined overexpression of MYC with a loss of SMARCA4 in granule cell precursors. Both alterations did not increase proliferation of granule cell precursors in vitro. However, combined MYC overexpression and SMARCA4 loss successfully induced tumor formation in vivo after orthotopic transplantation in recipient mice. Resulting tumors displayed anaplastic histology and exclusively consisted of SMARCA4 negative cells although a mixture of recombined and non-recombined cells was injected. These observations provide first evidence for a tumor-promoting role of a SMARCA4 deficiency in the development of medulloblastoma. In comparing the transcriptome of tumors to the cells of origin and an established Sonic Hedgehog medulloblastoma model, we gathered first hints on deregulated gene expression that could be specifically involved in SMARCA4/MYC driven tumorigenesis. Finally, an integration of RNA sequencing and DNA methylation data of murine tumors with human samples revealed a high resemblance to human Group 3 medulloblastoma on the molecular level. Altogether, the development of SMARCA4-deficient medulloblastomas in mice paves the way to deciphering the role of frequently occurring SMARCA4 alterations in Group 3 medulloblastoma with the perspective to explore targeted therapeutic options.
2023-09-26 | GSE235625 | GEO
Project description:MYC overexpression and SMARCA4 loss cooperate to drive medulloblastoma formation in mice
| PRJNA986571 | ENA
Project description:Medulloblastoma is a malignant childhood brain tumour comprising four discrete subgroups. To identify mutations that drive medulloblastoma we sequenced the entire genomes of 37 tumours and matched normal blood. One hundred and thirty-six genes harbouring somatic mutations in this discovery set were sequenced in an additional 56 medulloblastomas. Recurrent mutations were detected in 41 genes not yet implicated in medulloblastoma: several target distinct components of the epigenetic machinery in different disease subgroups, e.g., regulators of H3K27 and H3K4 trimethylation in subgroup-3 and 4 (e.g., KDM6A and ZMYM3), and CTNNB1-associated chromatin remodellers in WNT-subgroup tumours (e.g., SMARCA4 and CREBBP). Modelling of mutations in mouse lower rhombic lip progenitors that generate WNT-subgroup tumours, identified genes that maintain this cell lineage (DDX3X) as well as mutated genes that initiate (CDH1) or cooperate (PIK3CA) in tumourigenesis. These data provide important new insights into the pathogenesis of medulloblastoma subgroups and highlight targets for therapeutic development. A total of 76 pediatric medulloblastoma samples were analyzed, representing 4 expression classes
2012-07-05 | E-GEOD-37418 | biostudies-arrayexpress
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:Medulloblastoma is a malignant childhood brain tumour comprising four discrete subgroups. To identify mutations that drive medulloblastoma we sequenced the entire genomes of 37 tumours and matched normal blood. One hundred and thirty-six genes harbouring somatic mutations in this discovery set were sequenced in an additional 56 medulloblastomas. Recurrent mutations were detected in 41 genes not yet implicated in medulloblastoma: several target distinct components of the epigenetic machinery in different disease subgroups, e.g., regulators of H3K27 and H3K4 trimethylation in subgroup-3 and 4 (e.g., KDM6A and ZMYM3), and CTNNB1-associated chromatin remodellers in WNT-subgroup tumours (e.g., SMARCA4 and CREBBP). Modelling of mutations in mouse lower rhombic lip progenitors that generate WNT-subgroup tumours, identified genes that maintain this cell lineage (DDX3X) as well as mutated genes that initiate (CDH1) or cooperate (PIK3CA) in tumourigenesis. These data provide important new insights into the pathogenesis of medulloblastoma subgroups and highlight targets for therapeutic development.
2012-07-06 | GSE37418 | GEO
Project description:Medulloblastoma could be classified into four subtypes: Wnt, Shh, Group 3, and Group 4. Subtypes of medulloblastoma have distinct epigenetic properties. We report that a chromatin regulator SMARCA4/Brg1 controls a transcriptional program that specifically required for Shh-type medulloblastoma identity and proliferation. We show that Brg1 deletion significantly inhibited tumor formation and progression in a mouse medulloblastoma model. Genomic experiments indicate that Brg1 specifically coordinates with key transcription factors including Gli1, Atoh1, and REST to regulate the expression of both oncogenes and tumor suppressors. Shh-type medulloblastoma displays distinct H3K27me3 properties. We demonstrate that Brg1 modulates activities of H3K27me3 modifiers to regulate expression of medulloblastoma genes. Brg1 is important for the growth of a human medulloblastoma cell line and Brg1-regulated pathways are conserved in human Shh-type medulloblastoma. This study reveals a novel epigenetic mechanism that controls medulloblastoma development and provides a rationale for developing subtype-specific treatment strategies.
2016-09-14 | GSE69673 | GEO
Project description:Medulloblastoma could be classified into four subtypes: Wnt, Shh, Group 3, and Group 4. Subtypes of medulloblastoma have distinct epigenetic properties. We report that a chromatin regulator SMARCA4/Brg1 controls a transcriptional program that specifically required for Shh-type medulloblastoma identity and proliferation. We show that Brg1 deletion significantly inhibited tumor formation and progression in a mouse medulloblastoma model. Genomic experiments indicate that Brg1 specifically coordinates with key transcription factors including Gli1, Atoh1, and REST to regulate the expression of both oncogenes and tumor suppressors. Shh-type medulloblastoma displays distinct H3K27me3 properties. We demonstrate that Brg1 modulates activities of H3K27me3 modifiers to regulate expression of medulloblastoma genes. Brg1 is important for the growth of a human medulloblastoma cell line and Brg1-regulated pathways are conserved in human Shh-type medulloblastoma. This study reveals a novel epigenetic mechanism that controls medulloblastoma development and provides a rationale for developing subtype-specific treatment strategies.
2016-09-14 | GSE69672 | GEO
Project description:SMARCA4 encodes one of two mutually-exclusive ATPase subunits in the Brg/Brm associated factor (BAF) complex that is recruited by transcription factors to drive chromatin accessibility and transcriptional activation. SMARCA4 is among the most recurrently mutated genes in human cancer, including ~30% of germinal center (GC)-derived Burkitt lymphomas. In mice, GC-specific Smarca4 haploinsufficiency is able to cooperate with Myc over-expression to drive lymphomagenesis. Furthermore, monoallelic Smarca4 deletion drove GC hyperplasia with centroblast polarization via significantly increased rates of centrocyte recycling to the dark zone. Mechanistically, Smarca4 loss reduced the activity of transcription factors that are activated in centrocytes to drive GC-exit, including SPI1, IRF4 and NFκB. Loss of activity for these factors drove aberrant Bcl6 activity within murine centrocytes and human BL cells. Smarca4 therefore facilitates chromatin accessibility for transcription factors that shape centrocyte trajectories, and loss of fine-control of these programs biases towards centroblast cell-fate and GC hyperplasia.
2024-02-05 | GSE239937 | GEO
Project description:SMARCA4 knockdown upregulates expression of myogenic genes in medulloblastoma
| PRJNA815342 | ENA