Mus musculus
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ABSTRACT:
PROVIDER: PRJNA396419 | ENA |
REPOSITORIES: ENA
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Project description:Novel MYC-driven medulloblastoma models generated by CRISPR activation of endogenous Myc
| PRJNA396573 | ENA
Project description:Myc-driven Group 3 medulloblastoma (MB) is the most aggressive tumor among the four subgroups classified by transcriptome, genomic landscape and clinical outcomes. So far in all available mouse Group 3 models, the constitutive ectopic Myc expression was under control of LTR element or other exogenous promoters within the vectors, which were randomly inserted into the genome with multiple copies. Here we are deploying nuclease deficient CRISPR/dCas9-based transactivator that is targeted to promoter DNA sequences by specific guide RNA to force the transcriptional activation of endogenous Myc in p53-/-;cdkn2c-/- neurospheres cells. A combination of three sgRNAs together with dCas9-VP64 induced the highest expression of endogenous Myc. When the targeted cells were transplanted to the cortex of recipients, tumors arose fully recapitulate the Group 3 MB in human. This novel mouse model should significantly strengthen our understanding and treatment of the Myc-driven Group 3 medulloblastoma.
2018-06-19 | GSE102037 | GEO
Project description:Myc-driven Group 3 (G3) medulloblastoma (MB) is the most aggressive tumor among the four subgroups classified by transcriptome, genomic landscape and clinical outcomes. Several successful mouse models have been developed to recapitulate G3 MB tumor development; however, all models currently used facilitate tumorigenesis by constitutive ectopic expression of exogenously regulated Myc randomly integrated in multiple events into the genome. To overcome limitations of ectopically expressed Myc models, we used nuclease deficient CRISPR/dCas9-based transactivators in combination with specific single guide RNA (sgRNA) to force the transcriptional activation of endogenous Myc in Trp53-null neurosphere cells followed by orthotopic transplantations. Combination of three sgRNAs with dCas9-VP64 induced endogenous Myc expression and formed large cell anaplastic MBs which recapitulated the molecular characteristics of other mouse G3 MBs. This novel model more closely mimics human Myc-driven G3 MB disease development, and will be a valuable tool for future pre-clinical and therapeutic studies.
2018-06-12 | GSE102096 | GEO
Project description:Aberrant oncogenic activation of MYC drives tumorigenesis in the most aggressive subset of medulloblastoma, the most common malignant brain tumor in childhood. Metastatic dissemination at diagnosis and at recurrence is commonly observed in MYC-driven medulloblastomas. Since these tumors display remarkable resistance to standard multimodal therapeutic approaches, epigenetic modulators commonly altered in these tumors are highly promising targets for novel therapeutic approaches. Here, we report on a cross-entity, high-throughput epigenetic drug screen to evaluate therapeutic vulnerabilities in the most common malignant primary brain tumors. Specifically, we performed a primary screen including 78 epigenetic inhibitors and a secondary screen including 20 histone deacetylase inhibitors (HDACi) to compare response profiles in atypical teratoid/rhabdoid tumor (AT/RT, n=11), medulloblastoma (n=14), and glioblastoma (n=14). This unbiased approach revealed preferential activity of HDACi in MYC-driven medulloblastoma. Importantly, the class I selective HDACi CI-994 showed significant cell viability reduction mediated by induction of apoptosis in MYC-driven medulloblastoma, with little to no activity in non-MYC-driven medulloblastoma, AT/RT, and glioblastoma in vitro. Notably, CI-994 displayed antitumoral effects at the primary site and the metastatic compartment in two orthotopic mouse models of MYC-driven medulloblastoma. Furthermore, synergistic drug screening and RNA sequencing revealed NFκB pathway induction as a mechanism of resistance to CI-994 treatment. Taken together, our findings identified MYC pathway activation as a predictive biomarker for epigenetic treatment intervention in high-risk medulloblastoma and provide a preclinical rationale for further exploration of CI-994 combined with NFκB pathway inhibitors in the treatment of MYC-driven medulloblastoma.
2019-12-13 | GSE123760 | GEO
Project description:We examined the transformation susceptibility of different cerebellar stem/progenitors by developing several new Group3 medulloblastoma murine models using orthotopic transplantation and in utero electroporation (EP)-based in vivo gene transfer with Cre/LoxP-mediated conditional Myc gene activation and loss of Trp53 function. We used microarrays to compared the transcriptome of these novel Group3 medulloblastoma mouse models to existing mouse models of medulloblastoma subgroups and used cross-species analysis to compare these models to human medulloblastoma subgroups This study aimed to investigate the cell of origin of Group3 MB using our orthotopical MYC model followed by a novel electroporation approach. Orthotopic cell-lineage specific MYC tumors were generated by enforced Myc expression in P6 GNPs isolated from P0-1 tamoxifen treated [Atoh1-CreER;Trp53fl/-] and [Prom1-CreER;Trp53fl/-] mice followed by cortical implants in immunocompromised mice. These tumors are referred to as Atoh1ER-MYC [dka072-075], Prom1-CreER [dka077-081]. The first Group3 MB models in which tumors developed in situ were generated by electroporation of plasmids containing Myc and dominant negative Trp53 flanked by loxP sites into the fourth ventricle of E13.5 Blbp-Cre [dka081, 087, 089, 090, 091 and blm121], Gad2-IRES-Cre [blm128-130 and blm134] and Ptf1a-Cre [blm135-137] mouse embryos. The gene expression profile of these tumors were compared to our previously published Group3 MB model as well as SHH and WNT models of medulloblastoma. For SHH subgroup medulloblastoma, [dka001-005, 009, 033 and 034] and [dka050-057], spontaneous medulloblastomas from [Cdkn2c-/-; Trp53Fl/Fl; Nestin-Cre] and [Cdkn2c-/-; Ptch1+/-] (Uziel et al.,2005 Genes Dev) were used, respectively. For Group3 medulloblastomas, [dka013-16, 049 and 065-067], in which Myc was overexpressed in Cdkn2c-/-, Trp53-/- cerebellar cells and implanted into the cortices of immunocompromised nude mice prior to tumor isolation. For WNT subgroup medulloblastomas [pgr003, 016 and 066], spontaneously developed tumors from CTNNB1+/lox (ex3); BLBP-Cre; Trp53Fl/Fl (Gibson et al., 2010, Nature) were removed for RNA extraction.
2015-02-13 | E-GEOD-65888 | biostudies-arrayexpress
Project description:We examined the transformation susceptibility of different cerebellar stem/progenitors by developing several new Group3 medulloblastoma murine models using orthotopic transplantation and in utero electroporation (EP)-based in vivo gene transfer with Cre/LoxP-mediated conditional Myc gene activation and loss of Trp53 function. We used microarrays to compared the transcriptome of these novel Group3 medulloblastoma mouse models and CPC mouse models to existing mouse models of medulloblastoma subgroups and used cross-species analysis to compare these models to human medulloblastoma subgroups
2015-02-13 | GSE65888 | GEO
Project description:Group 3 medulloblastoma is often associated with MYC amplification or overexpression, while whether MYC overexpression alone is sufficient to induce tumorigenesis is unknown and the cell type(s) which can be transformed by MYC is unclear. Here, by generating a new mouse model, we demonstrated that overexpression of Myc alone is sufficient to transform astrocyte progenitors and granule neuron progenitors (GNP) in the early postnatal cerebellum following orthotopic transplantation. The resulting tumors resemble human Group 3 medulloblastoma in terms of both histology and gene expression profiles. Using these models we found that inhibition of lactate dehydrogenase A (LDHA) significantly reduced both murine and human MYC-driven tumor growth, but did not affect SHH medulloblastoma, indicating that LDHA is potential and specific therapeutic target for MYC-driven medulloblastoma.
2019-04-25 | GSE114760 | GEO
Project description:Myc-driven medulloblastoma cells treated with Panobinostat (LBH589)
| PRJNA285506 | ENA
Project description:Medulloblastoma is the most common malignant brain tumor of childhood. The highest-risk tumors are driven by recurrent Myc amplifications (Myc-MB) and experience poorer outcomes despite intensive multimodal therapy. The Myc transcription factor defines core regulatory circuitry for these tumors and acts to broadly amplify downstream pro-survival transcriptional programs. Therapeutic targeting of Myc directly has proven elusive, but inhibiting transcriptional cofactors may present an indirect means of drugging the oncogenic transcriptional circuitry sustaining Myc-MB. Independent CRISPR-Cas9 screens were pooled to identify conserved dependencies in Myc-MB. We performed chromatin conformation capture (Hi-C) from primary patient Myc-MB samples to map enhancer-promoter interactions. We then treated in vitro and xenograft models with the dual CDK9/7 inhibitor zotiraciclib to evaluate effect on Myc-driven programs and tumor growth. Eight CRISPR-Cas9 screens performed across three independent labs identify CDK9 as a conserved dependency in Myc-MB. Myc-MB cells are susceptible to CDK9 inhibition, which is synergistic with concurrent inhibition of CDK7. The dual CDK9/7 inhibitor zotiraciclib disrupts enhancer-promoter activity in Myc-MB and downregulates Myc-driven transcriptional programs, exerting potent anti-tumor effect.
2024-11-14 | GSE267471 | GEO