Project description:Treatment-resistance of lethal high-grade brain tumors including H3K27M diffuse midline gliomas is thought to arise in part from transcriptional and electrophysiological heterogeneity. These phenotypes are readily studied in isolation using single-cell RNA-seq and whole-cell patch clamping, respectively, but their simultaneous capture is now possible by aspirating a cell's contents into a patch pipet after electrophysiology recordings using a method called 'patch-seq'. Here, we adapt this method to characterize the gene expression programs and functional responses of patient-derived glioma xenografts to neuronal firing at single-cell resolution.
Project description:PDGFRA is commonly altered in pediatric high grade gliomas including in histone 3 lysine 27-mutated diffuse midline gliomas (H3K27M DMG), a disease with almost no long-term survivors. We describe effective CNS penetration of a PDGFRA inhibitor with pharmacologically relevant concentrations in brain tumor tissue resulting in dramatic clinical effect and minimal side effects in a cohort of 9 pediatric high grade glioma cases.
Project description:Mutations in the gene encoding histone H3, p.K28M(K27M) and p.G35R/V(G34R/V), are the major driver gene mutations in gliomas. H3 p.K28M(K27M) mutations are frequently found in gliomas arising in midline structures, so called H3K27M-diffuse midline glioma (DMG), while H3 p.G35R/V(G34R/V) mutations are frequently found in pediatric hemispheric gliomas, so called H3G34R/V-diffuse hemispheric glioma (DHG). In contrast, hemispheric glioma with H3 p.K28M(K27M) mutation, known as H3K27M-DHG, is a rare entity and its clinical and molecular characteristics remain to be fully elucidated. We describe a 41-year-old female patient with the right parietal lobe tumor. Following a gross total resection, the pathology showed a high-grade astrocytoma. Sanger sequencing revealed an H3K27M mutation and an IDH1/2-wildtype, leading to the integrated diagnosis of H3K27M-DHG. She underwent chemoradiotherapy with temozolomide and suffered recurrences twice until her death 55 months after the initial diagnosis. The deoxyribonucleic acid methylation profiling classified the tumor as DMG, H3K27-altered, suggesting that it molecularly belonged to the variant of DMG despite a non-median location. Next-generation sequencing on the recurrent tumor detected fibroblast growth factor receptor (FGFR)1 mutation, a favorable prognostic factor in H3K27M-DMG. A relatively prolonged survival of our patient suggests that FGFR1 mutations may also contribute to a better prognosis in H3K27M-DHG.
Project description:H3K27-mutant diffuse hemispheric glioma presenting typical molecular features of diffuse midline glioma: A case report and literature review.
Project description:The blood-brain barrier (BBB) plays important roles in brain tumor pathogenesis and treatment response, yet our understanding of its function and heterogeneity within or across brain tumor types remains poorly characterized. Here we analyze the neurovascular unit (NVU) of pediatric high-grade glioma (pHGG) and diffuse midline glioma (DMG) using patient derived xenografts and natively forming glioma mouse models. We show tumor-associated vascular differences between these glioma subtypes, and parallels between PDX and mouse model systems, with DMG models maintaining a more normal vascular architecture, BBB function and endothelial transcriptional program relative to pHGG models. Unlike prior work in angiogenic brain tumors, we find that expression of secreted Wnt antagonists do not alter the tumor-associated vascular phenotype in DMG tumor models. Together, these findings highlight vascular heterogeneity between pHGG and DMG and differences in their response to alterations in developmental BBB signals that may participate in driving these pathological differences.
Project description:We systematically evaluated B7-H3–targeting CAR-T cells derived from three monoclonal antibodies (376.96, MGA271, and Hu8H9) in diffuse midline glioma (DMG or DIPG), a fatal pediatric brain tumor. Among these, 376.96 CAR-T cells had markedly lower tonic signaling, diminished expression of exhaustion markers, and enhanced tumor killing, cytokine production, and persistence. Transcriptomic and epigenomic profiling revealed a restrained activation state with reduced tonic signaling pathways and elevated stemness properties, oxidative metabolism, and innate immune sensing in these cells. In patient-derived spheroids and orthotopic DIPG xenografts, mRNA-based 376.96 CAR-T cells achieved robust tumor control and extended survival. By leveraging epitope selection, we reveal a mechanistic link between tonic signaling and CAR-T cell exhaustion, and provide a rational framework for optimizing CAR-T cell design to achieve improved efficacy and durability in pediatric brain tumor therapy.