Transcriptional Regulation of Protein Synthesis by Mediator Kinase Represents a Therapeutic Vulnerability in MYC-driven Medulloblastoma
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PROVIDER: PRJNA1181569 | ENA |
REPOSITORIES: ENA
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Project description:MYC-driven medulloblastoma (MB) is a highly aggressive cancer type with poor prognosis and limited treatment options. Through CRISPR-Cas9 screening of MB cell lines, we identified the Mediator-associated kinase CDK8 as a critical regulator of MYC-driven MB. Loss of CDK8 substantially reduces MYC expression, induces pronounced transcriptional changes, suppresses monosome assembly, and decreases ribosome biogenesis and protein synthesis, consequently inhibiting MB growth. Mechanistically, CDK8 regulates the occupancy of RNA polymerase II at specific chromatin loci, facilitating an epigenetic alteration that promotes the transcriptional regulation of ribosomal genes. Targeting CDK8 effectively diminishes the stem-like neoplastic cells characterized by hyperactive ribosome biogenesis. Furthermore, we demonstrated that the combined inhibition of CDK8 and mTOR synergizes to optimize therapeutic outcomes in vivo and in vivo. Overall, our findings establish a connection between CDK8-mediated transcriptional regulation and mRNA translation, suggesting a promising new therapeutic approach that targets the protein synthesis for MYC-driven MB.
2024-12-01 | GSE280973 | GEO
Project description:PHGDH Arginine Methylation by PRMT1 Promotes Serine Synthesis and Represents a Therapeutic Vulnerability in Hepatocellular Carcinoma
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Project description:Serine synthesis is crucial for tumor growth and survival, but its regulatory mechanism in cancer remains elusive. Here, using integrative metabolomics and transcriptomics analyses, we show a heterogeneity between metabolite and transcript profiles. Specifically, the level of serine in HCC tissues is increased, whereas the expression of phosphoglycerate dehydrogenase (PHGDH), the first rate-limiting enzyme in serine biosynthesis pathway, is dramatically downregulated. Interestingly, the increased serine level is obtained by enhanced PHGDH catalytic activity due to protein arginine methyltransferase 1 (PRMT1)-mediated methylation of PHGDH at arginine 236. PRMT1-mediated PHGDH methylation and activation potentiates serine synthesis, ameliorates oxidative stress, and promotes HCC growth in vitro and in vivo. FBXO7, an E3 ubiquitin ligase which is downregulated in human HCC tissues, ubiquitinates and downregulates PRMT1 to suppress PHGDH methylation and serine synthesis, leading to the inhibition of HCC cell growth. Furthermore, PRMT1-mediated PHGDH methylation correlates with PHGDH hyperactivation and serine accumulation in human HCC tissues, and is predictive of poor prognosis of HCC patients. Notably, blocking PHGDH methylation with a TAT-tagged non-methylated peptide inhibits serine synthesis and restrains HCC growth, both in an HCC patient-derived xenograft (PDX) model and subcutaneous HCC cell-derived xenograft model. Overall, our findings reveal a novel regulatory mechanism of PHGDH activity and serine synthesis, and suggest PHGDH methylation as a potential therapeutic vulnerability in HCC.
2022-07-11 | GSE207435 | GEO
Project description:ATR represents a therapeutic vulnerability in clear cell renal cell carcinoma
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Project description:N-myc mediated translation control is a therapeutic vulnerability in medulloblastoma
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Project description:SNRPD3 preserves balanced MYCN-driven alternate splicing and represents a therapeutic vulnerability in neuroblastoma
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Project description:Deregulation of N-myc is a leading cause of malignant brain tumors in children. To target N-myc-driven medulloblastoma, most research has focused on identifying genomic alterations or on the analysis of the medulloblastoma transcriptome. Here, we have broadly characterized the translatome of medulloblastoma and shown that N-myc unexpectedly drives selective translation of transcripts that promote protein homeostasis. Cancer cells are constantly exposed to proteotoxic stress associated with alterations in protein production or folding. It remains poorly understood how cancers cope with proteotoxic stress to promote their growth. Here, our data unexpectedly revealed that N-myc regulates the expression of specific components (~5%) of the protein folding machinery at the translational level through the major cap binding protein, eukaryotic initiation factor eIF4E. Reducing eIF4E levels in mouse models of medulloblastoma blocked tumorigenesis. Importantly, targeting Hsp70, a protein folding chaperone translationally regulated by N-myc, suppressed tumor growth in mouse and human medulloblastoma xenograft models. These findings reveal a previously hidden molecular program that promotes medulloblastoma formation and identify new therapies that may have impact in the clinic.
2022-10-18 | GSE215298 | GEO
Project description:Metabolically-targeted therapies hold the promise of offering an effective and less toxic treatment for tumours including medulloblastoma, the most common malignant brain tumour of childhood. Current treatment relies on the sensitivity of these tumours to DNA damage that was discovered more than 50 years ago. Finding new tumour-specific susceptibilities to complement sensitivity to DNA damage is key to developing new more effective adjuvant therapies. The specific metabolic program of tumours is an attractive vulnerability, as restriction diet are low cost and easy to implement. Here, we present compelling pre-clinical evidence that glutamine restriction diet can be used as an adjuvant treatment for p73-expressing medulloblastoma.
2017-08-24 | ST000898 | MetabolomicsWorkbench
Project description:Transcriptional repression of ribosomal components and tRNAs is coordinately regulated in response to a wide variety of environmental stresses. Part of this response involves the convergence of different nutritional and stress signaling pathways on Maf1, a protein that is essential for repressing transcription by RNA polymerase (pol) III in Saccharomyces cerevisiae. Here we identify the functions buffering yeast cells that are unable to down-regulate transcription by RNA pol III. MAF1 genetic interactions identified in screens of non-essential gene-deletions and conditionally-expressed essential genes reveal a highly interconnected network of 64 genes involved in ribosome biogenesis, RNA pol II transcription, tRNA modification, ubiquitin-dependent proteolysis and other processes. A survey of non-essential MAF1 synthetic sick/lethal (SSL) genes identified six gene-deletions that are defective in transcriptional repression of ribosomal protein (RP) genes following rapamycin treatment. This subset of MAF1 SSL genes included MED20 which encodes a head module subunit of the RNA pol II Mediator complex. Genetic interactions between MAF1 and subunits in each structural module of Mediator were investigated to examine the functional relationship between these transcriptional regulators. Gene expression profiling identified a prominent and highly selective role for Med20 in the repression of RP gene transcription following treatments with rapamycin, chlorpromazine and tunicamycin and in post-diauxic cells. In addition, attenuated repression of RP genes by rapamycin was observed in a strain deleted for the Mediator tail module subunit Med16. The data suggest that Mediator and Maf1 function in parallel pathways to negatively regulate RP mRNA and tRNA synthesis. Keywords: genetic modification, stress response We generated 12 microarray profiles from fluor-reversed replicates of wild-type and med20? strains with or without treatment with rapamycin and under 5 other conditions that repress ribosomal protein gene transcription. The effect of rapamycin on strains deleted for 3 other Mediator subunits was also assessed relative to wild-type. See Willis et al., (2008) in revision.
2008-06-01 | E-GEOD-11397 | biostudies-arrayexpress
Project description:Here we present the case of adult medulloblastoma with minimal chromosomal rearrangements. Data presented here are aCGH analyses of two biopsies of adult patient with a medulloblastoma which was classified as a Shh subgroup. Analyses were performed on 2 archival specimens of medulloblastoma, WHO Grade IV, seen at the Department of Pathology, Massachusetts General Hospital from 2007. This Series represents the CGH part of the study.
2013-01-01 | E-GEOD-41990 | biostudies-arrayexpress