Project description:Diffuse midline gliomas (DMG) are aggressive tumors with a poor prognosis. In this study, a technique called t-SNE analysis was used to cluster tumors based on their methylation profiles. DMG subtype with a co-occurrence of H3.3K27M and BRAF or FGFR1 mutations have been identified. This subtype has a more favorable prognosis, with a median overall survival of 3 years.
Project description:Diffuse Midline Glioma (DMG) syngeneic orthotopic murine mouse models were used as high fidelity model of human DMG tumors as they recapitulate the heterogeneity, cell states and OncoTarget/OncoTreat drug predictions of human DMG tumors.
Project description:H3K27-altered Diffuse Midline Glioma (DMG) is a universally fatal paediatric brainstem tumour. The prevalent driver mutation H3K27M creates a unique epigenetic landscape that may also establish therapeutic vulnerabilities to epigenetic inhibitors. From a wider screen of an epigenetic inhibitor library, we identified PRMT5 inhibitors as amongst the top hits reducing DMG cell viability. Here, we treated HSJD-DIPG-007 +/- the PRMT5 inhibitor LLY-283. RNA-sequencing was performed at 0, 1, 2, 3, 5, 7 and 10 days to assess the changes in gene expression following PRMT5 inhibition in DMG cells. This shows that PRMT5 inhibition changes expression in genes associated with multiple disease relevant phenotypes, including sterol metabolism, differentiation, and the extracellular matrix. By characterising the changes in the transcriptome following PRMT5 inhibition this provides crucial insights into the potential of PRMT5 inhibitors as a treatment for H3K27-altered DMG.
Project description:Characterisation of a new subgroup of DMG lacking H3-K27M mutation that is defined by H3K27me3 loss and EZHIP overexpression that can be detected by IHC. These tumors are distinct from EZHIP-positive posterior fossa ependymomas and are associated with a dismal prognosis. We propose that these EZHIP/H3-WT tumors need to be considered similar to canonical DIPG/DMG, thus extending the spectrum of DMG with PRC2 inhibition beyond H3-K27M mutation
Project description:Lariat RNAs, generated as by-products of RNA splicing from excised introns, must be removed. RNA debranching enzyme (DBR1) is the core factor responsible for lariat RNA removal. However, the mechanism by which DBR1 debranches lariat RNAs remains unclear. Here, we demonstrate that six ALBA (Acetylation Lowers Binding Affinity) proteins interact with DBR1 to enhance its debranching activity and facilitate DBR1's accessibility to lariat RNAs, thereby promoting lariat RNA turnover. Similar to dbr1, alba mutants exhibit pleiotropic developmental defects and accumulate lariat RNAs. ALBAs bind to lariat RNAs via their C-terminal RGG/RG-rich repeats and assist DBR1 in binding to these RNAs. The N-terminal ALBA domain mediates the interaction with DBR1 and enhances its enzymatic activity. Cold stress induces lariat RNA accumulation by attenuating the ALBA–DBR1 interaction, which in turn reduces the induction of cold-responsive genes by impairing their transcription. Together, these findings uncover that lariat RNA turnover requires ALBA proteins.