A Functional Role of OLIG2 in Tumor Heterogeneity of MYC-amplified Medulloblastoma
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE188887 | GEO | 2021/11/20
REPOSITORIES: GEO
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2022-07-01 | GSE206225 | GEO
Project description:The goal of this study was to compare gene expression profiles of MYC-amplified medulloblastoma tumors under three distinct conditions: primary tumors prior to radiation treatment, tumors derived from implanted radio-resistant tumor cells, and spontaneously recurring tumors several weeks post-irradiation. The purpose of this experiment was to identify the moleular pathways that are impacted during radiation and those which contribute to tumor recurrence. Unsupervised hierarchical cluster analysis revealed that the tumors which spontaneously recurred in vivo closely resembled the primary tumors. Tumors from implanted post-radiation neurospheres, however, had markedly different profiles. We identified 44 upregulated and 23 downregulated genes in the spontaneously recurred tumors compared to untreated primary tumors. Furthermore, we identified 817 upregulated and 509 downregulated genes in tumors derived from implanted post-radiation neurospheres compared to untreated primary tumors. Among these genes, 756 (57%) genes were also differentially expressed between tumors derived from implanted post-radiation neurospheres and spontaneously recurrent tumors. The downregulated pathways in tumors derived from implanted post-radiation neurospheres were associated with p53, cell cycle, DNA replication, and DNA damage, and the upregulated genes are involved in metabolic pathways. This study demonstrates that radiation resistant tumor cells exhibit differential gene expression post-irradiation and during tumor recurrence and provides a framework for the study of genetic pathways leading to tumor recurrence post-irradiation.
2021-11-16 | GSE188789 | GEO
Project description:Pediatric medulloblastoma (MB) is the most common solid malignant brain neoplasm, with group 3 (G3) MB representing the most aggressive subgroup associated with a poor prognosis and a remarkable ability to resist upfront multimodal therapy. Despite a low mutational burden of disease and MYC amplification identified as a independent factor associated with poor survivorship, efforts to target the MYC has met with limited therapeutic success. Consequently alternative mediators associated with the aggressive phenotype of G3 MB continues as a common goal within the MB community. Here we show how the neural stem cell determinant Musashi 1 (MSI1) is a central and vital moderator of G3 MB in both a MYC amplified mouse model of G3 MB and patient derived xenografts (PDX). Specifically, we modified the MYC amplified and p53 mutated (MP) mouse model of G3 MB to generate Msi1 conditional knockout mice (Msi1flox/flox), which led to the observation that MSI1 is required for tumor initiation of MP tumors. To identify the translational potential of these findings, we employed shRNA against Msi1 in multiple PDX lines, observing a striking deficit in multiple key stem cell features including self-renewal, proliferation, and failure to progress through the cell cycle. Notably, Msi1 inhibition resulted in a failure of tumor initiation, translating to a significantly prolonged survival, reaffirming the essential role for MSI1 in G3 MB. To determine how MSI1 symphonizes the anarchic post-transcriptional landscape of G3MB, we differentially analyzed the MSI1 binding sites in normal neural stem cells and G3 MB and subsequently compared the MSI1-binding transcriptome, and proteome following Msi1 inhibition. Comparative analysis suggested an integral role for post-transcriptional regulators, such as MSI1 and its binding prey mRNA, as a therapeutic target. Here we propose the neural RNA binding protein MSI1, as a master regulator, hijacked from its normal neural developmental function, orchestrating the aberrant translational landscape of G3 MB.
2022-07-19 | GSE134597 | GEO
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
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 | GSE267470 | GEO
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 | GSE267469 | GEO
Project description:We and others have demonstrated that MYC-amplified medulloblastoma (MB) cells are susceptible towards treatment with class I histone deacetylase inhibitors (HDACi). However, single drug treatment with HDACi has shown limited clinical efficacy. We hypothesized that addition of a second compound acting synergistically with HDACi may enhance efficacy. Gene expression changes in HDACi entinostat-treated cells identified, the cell cycle protein PLK1 as a potential second target. Indeed, MYC-amplified tumor cells are highly sensitive towards treatment with ATP-competitive PLK1 inhibitors as monotherapy. Moreover, entinostat and PLK1i in combination act synergistically in MYC-driven MB, exerting cytotoxic effects at clinically relevant concentrations. The downstream effect of both drugs as monotherapy and in combination is exerted via MYC-related pathways, pointing out the potential of MYC amplification as a clinically feasible predictive biomarker for patient selection. While entinostat significantly extended survival of mice implanted with orthotopic MYC-amplified MB PDX, there was no evidence of the improvement of survival when treating the animals with combination. However, further screening of blood-brain barrier penetrating PLK1is is necessary to determine the true potential of the combination. We use microarry to interrogate the expression differences in vehicle, entinostat, volasertib or combination treated cells.
2023-05-15 | GSE220748 | GEO
Project description:As the most life-threatening subtype of pediatric medulloblastoma (MB), MYC-amplified Group 3 (G3) MB lacks effective and selective therapeutics. We tried to indirectly target MYC (oncogenic driver and cancer-dependent molecule) production via inhibiting translational machinery. Through multiple datasets analyses on components of eIF4F (eukaryotic translation initiation factor 4F) complex, we found that EIF4A1 (major component with RNA helicase activity) has relatively higher expression level and the closest positive correlation with MYC in G3-MB among normal control and other 3 subtypes (e.g., WNT, SHH and G4). Both in vitro and in vivo experiments with MYC-amplified G3-MB cell lines showed effective growth inhibition upon EIF4A1 knockout or inhibitor treatment. Further FACS analysis found decreased cell proliferation and enhanced apoptosis on EIF4A1 inhibitor treatment. To explore the mechanisms of EIF4A1 inhibition on arresting MYC-amplified G3-MB, we performed the whole proteome analyses on corresponding MB cells treated with EIF4A1 inhibitor.
2020-10-15 | PXD022014 |
Project description:MYC-driven Group 3 medulloblastoma (MB) (subtype II) is a highly aggressive childhood brain tumor. Sensitivity of MYC-driven MBs to class I histone deacetylase inhibitors (HDACi) has been previously demonstrated in vitro and in vivo. We here characterize the transcriptional effects of class I HDAC inhibition in MYC-driven MB and explore beneficial drug combinations. MYC-amplified Group 3 MB cells (HD-MB03) were treated with class I HDACi entinostat. Changes in the gene expression profile compared to untreated control were quantified on a microarray. Gene set enrichment analysis, cytoscape enrichment mapping and ingenuity pathway analysis led to the identification of pathways affected by entinostat treatment. Five drugs interfering with these pathways (olaparib, idasanutlin, ribociclib, selinexor, vinblastine) were tested as single agents in metabolic activity assays in three MYC-amplified and two non-MYC-amplified MB cell lines. Synergy with entinostat was evaluated by dose response curve shift, combination index and zero interaction potency synergy model and validated in cell count and flow cytometry experiments in two MYC-amplified and one non-MYC-amplified MB cell line. The effect of the most promising drug combination (entinostat and olaparib) on DNA damage was evaluated by γH2A.X quantification in immunoblotting, fluorescence microscopy and flow cytometry. Entinostat treatment changed the expression of genes involved in 22 pathways, including downregulation of DNA damage response. The PARP1 inhibitors olaparib and pamiparib showed synergy with entinostat. The combination of entinostat and olaparib led to increased cell death, decreased viability and increased formation of double strand breaks selectively in MYC-amplified MB cells. MYC-amplified MB cells treated with entinostat and olaparib were particularly vulnerable to additional induction of DNA damage by doxorubicin. Non-MYC-amplified MB cells and normal human fibroblasts were not susceptible to this triple treatment. Our study identifies the combination of entinostat with olaparib and doxorubicin as a new potential therapeutic approach for MYC-driven Group 3 MB.
2023-10-04 | GSE232148 | GEO
Project description:Medulloblastoma (MB) is the most common malignant brain tumor in children. Patients whose tumors exhibit overexpression or amplification of the MYC oncogene (c-MYC) usually have an extremely poor prognosis, but there are no animal models of this subtype of the disease. Here we show that cerebellar stem cells expressing Myc and mutant Trp53 (p53) generate aggressive tumors following orthotopic transplantation. These tumors consist of large, pleiomorphic cells and resemble human MYC-driven MB at a molecular level. Notably, antagonists of PI3K/mTOR signaling, but not Hedgehog signaling, inhibit growth of tumor cells. These findings suggest that cerebellar stem cells can give rise to MYC-driven MB, and identify a novel model that can be used to test therapies for this devastating disease. To gain insight into the pathways that control growth of MYC-driven MB, we compared gene expression profiles of murine Myc/DNp53 (MP) tumor cells to those of freshly isolated cerebellar stem cells (Prom1+Lin- cells) and of tumors from Ptch1 mutant mice (a model for Sonic Hedgehog-associated MB). RNA was isolated from stem cells and tumor cells using the RNAqueous kit (Ambion). RNA was labeled and hybridized to Affymetrix Mouse Genome 430 2.0 arrays.
2011-12-05 | GSE34126 | GEO