Activity of PDGFRA inhibitor Avapritinib in H3K27M Diffuse Midline Glioma
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE222457 | GEO | 2026/01/01
REPOSITORIES: GEO
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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.
2025-12-31 | GSE286743 | GEO
Project description:Diffuse midline glioma (DMG) is a fatal childhood brain tumour characterised primarily by mutant histone H3 (H3K27M). H3K27M causes a global reduction in Polycomb Repressive Complex 2 (PRC2)-mediated H3K27me3 by inhibiting the enzymatic activity of the complex. Paradoxically, PRC2 histone methyltransferase activity is essential in for oncogenic gene repression in DMG tumour cells though downstream molecular mechanisms that are poorly understood. Here, we discover that this oncogenic gene repression is mediated by specific canonical PRC1 (cPRC1) formations containing CBX4. By combining CRISPR screening, biochemical and chromatin mapping approaches with functional perturbations we show that cPRC1 complexes containing CBX4-cPRC1 is co-opted to drive repression downstream of H3K27me3 in DMG cells. Remarkably, the altered H3K27me3 landscape characteristic of H3K27M-mutant DMG rewires the distribution of distinct cPRC1 complexes such that CBX4-cPRC1 accumulates at sites of H3K27me3 while other cPRC1 formations are reduced. Despite CBX4-cPRC1 accounting for less than 5% all cPRC1 H3K27M-mutant DMG, it acts as the predominant repressor of (Polycomb target) neural differentiation genes in this setting. Our findings link the altered distribution of H3K27me3 with imbalances of CBX-cPRC1 functions and consequent oncogenic gene repression, revealing new disease mechanisms and potential therapeutic opportunities in this incurable childhood brain tumour.
2025-06-24 | PXD047401 | Pride
Project description:Abstract Background: Diffuse midline gliomas (DMGs) with histone H3K27M mutations represent a devastating paediatric brain cancer characterized by abysmal prognosis and limited treatment options. The only approved treatment is radiotherapy (RT), but most of the tumours relapse with fatal consequences. In this study, we sought to investigate whether irradiation leads to senescence induction and explore the efficacy of senolytics against DMG. Methods: We have characterised the senescent phenotype of five genetically heterogeneous H3K27M-altered human DMG cell lines, combining cellular and/or molecular approaches. The sensitivity of senescent cells to Bcl-xL inhibition has been demonstrated in dose/response curves in vitro and in a PDX model of DMG. Results: Here, we show that ionizing radiation induces senescence and SASP responses in both TP53 mutant and wild-type H3K27M-altered human DMG cell lines. We identify Navitoclax as a potent senolytic agent that selectively targets senescent DMG cells into apoptosis by inhibiting Bcl-xL. Related compounds, such as a proteolysis-targeting chimera (PROTAC)-mediated Bcl-xL degradation and a galacto-conjugated form of Navitoclax also show an effective senolytic activity in senescent cancer cells. Finally, we show that a combination therapy of irradiation and Navitoclax results in reduced tumor burden and increased mouse survival in an orthotopic xenograft DMG model. Conclusion: These results offer a rationale for further clinical development of senolytic therapies as part of multimodal treatment approaches for DMG patients/
2025-07-03 | GSE291046 | GEO
Project description:Aberrant epigenetic regulation is a hallmark of Diffuse Midline Glioma (DMG), an incurable pediatric brain tumor. The H3K27M driver histone mutation leads to transcriptional dysregulation, indicating that targeting the epigenome and transcription may be a key therapeutic strategy against this highly aggressive cancer. One such target is the Facilitates Chromatin Transcription (FACT) histone chaperone. We found FACT to be enriched at developmental gene promoters, coinciding with regions of open chromatin and binding motifs of core DMG regulatory transcription factors. Furthermore, FACT interacted and co-localized with the Bromodomain and Extra-Terminal Domain (BET) protein BRD4 at promoters and enhancers, suggesting functional cooperation between FACT and BRD4 in DMG. In vitro, a combinatorial therapeutic approach using the FACT inhibitor CBL0137, coupled with BET inhibition revealed potent and synergistic cytotoxicity across a range of DMG cultures, with H3K27M-mutant cells demonstrating heightened sensitivity. These results were recapitulated in vivo, significantly extending survival in three independent orthotopic PDX models of DMG. Mechanistically, we show that CBL0137 treatment decreased chromatin accessibility, synergizing with BET inhibition to disrupt transcription, silencing several key oncogenes including MYC, PDGFRA and MDM4, alongside alterations to the splicing landscape. Combined, these data highlight the therapeutic promise of simultaneously targeting FACT and BRD4 in DMG, proposing a novel strategy for combating this devastating pediatric brain tumor.
2025-12-22 | GSE272129 | GEO
Project description:Aberrant epigenetic regulation is a hallmark of Diffuse Midline Glioma (DMG), an incurable pediatric brain tumor. The H3K27M driver histone mutation leads to transcriptional dysregulation, indicating that targeting the epigenome and transcription may be a key therapeutic strategy against this highly aggressive cancer. One such target is the Facilitates Chromatin Transcription (FACT) histone chaperone. We found FACT to be enriched at developmental gene promoters, coinciding with regions of open chromatin and binding motifs of core DMG regulatory transcription factors. Furthermore, FACT interacted and co-localized with the Bromodomain and Extra-Terminal Domain (BET) protein BRD4 at promoters and enhancers, suggesting functional cooperation between FACT and BRD4 in DMG. In vitro, a combinatorial therapeutic approach using the FACT inhibitor CBL0137, coupled with BET inhibition revealed potent and synergistic cytotoxicity across a range of DMG cultures, with H3K27M-mutant cells demonstrating heightened sensitivity. These results were recapitulated in vivo, significantly extending survival in three independent orthotopic PDX models of DMG. Mechanistically, we show that CBL0137 treatment decreased chromatin accessibility, synergizing with BET inhibition to disrupt transcription, silencing several key oncogenes including MYC, PDGFRA and MDM4, alongside alterations to the splicing landscape. Combined, these data highlight the therapeutic promise of simultaneously targeting FACT and BRD4 in DMG, proposing a novel strategy for combating this devastating pediatric brain tumor.
2025-12-22 | GSE272131 | GEO
Project description:Diffuse intrinsic pontine glioma (DIPG) and other H3K27M-mutated diffuse midline gliomas (DMGs) are universally lethal central nervous system (CNS) tumors that occur most commonly in children and young adults1. Average life expectancy is ten months from diagnosis, and 5-year survival is less than 1%2. Palliative radiotherapy is the only established treatment3, and neither cytotoxic nor targeted pharmacological approaches have demonstrated anti-tumor responses or improved prognosis to date3,4. We previously discovered that the disialoganglioside GD2 is highly and uniformly expressed on H3K27M+ DMG cells and demonstrated that intravenously (IV) administered GD2.4-1BB.z chimeric antigen receptor (CAR) T-cells eradicated established DMGs in patient-derived orthotopic murine models5, thereby providing the rationale for a first-in-human/first-in-child Phase 1 clinical trial (NCT04196413). Because CAR T-cell-induced inflammation and edema of the brainstem can result in obstructive hydrocephalus, increased intracranial pressure, and dangerous tissue shifts, a number of neurocritical care precautions were incorporated in the clinical trial design and management plan. Here we present the clinical experience from the first four patients with H3K27M+ DMG treated with GD2-CAR T-cells at dose level 1 (DL1; 1e6 GD2-CAR T-cells/kg administered IV). Patients who exhibited clinical benefit were eligible for subsequent administrations of GD2-CAR T-cells. Given preclinical evidence for increased CAR T-cell potency6, and the potential for diminished immunogenicity with locoregional administration, second doses were administered intracerebroventricularly (ICV) through an Ommaya catheter to three patients. As predicted from preclinical models, toxicity was largely related to the neuroanatomical location of the tumors and was reversible with intensive supportive care. Although GD2 is expressed at low levels in normal neural tissue, no evidence of on-target, off-tumor toxicity was observed. Three of four patients exhibited clinical and radiographic improvement, underscoring the promise of this approach for H3K27M+ DMG therapy. Correlative studies of serum and CSF revealed marked proinflammatory cytokine production following GD2 CAR T cell administration and single cell transcriptomic analysis of 65,598 single cells from CAR T cell products and patient CSF has begun to reveal differences that correlate with the heterogeneity between subjects and routes of administration.
2022-02-07 | GSE186802 | GEO
Project description:Pediatric high-grade gliomas, including diffuse midline gliomas (DMG), harbor mutually exclusive tumor location specific histone mutations. Using immunocompetent genetically engineered mouse models, we demonstrate the predominant non-neoplastic cell population are infiltrating myeloid cells, including peripheral monocytes and brain resident microglia. Single cell RNA sequencing, flow cytometry, and immunohistochemistry demonstrate the presence of unique myeloid cell populations distinctly shaped by the specific histone mutation. Disease associated myeloid cell phenotypes are identified, resembling those found in other neurodegenerative diseases, and demonstrate immune permissive characteristics. H3.3K27M DMGs, the most aggressive DMG subtype, demonstrate enrichment of disease associated myeloid cells as well as proliferating myeloid and tumor cells.
2024-10-11 | GSE245716 | GEO
Project description:The outcome for children with high-grade gliomas (HGG) remains dismal, with a two-year survival rate of only 10-30%. Approximately half of pediatric HGGs are diffuse intrinsic pontine glioma (DIPG), a brainstem tumor that arises almost exclusively in children. Genome-wide analyses of copy number imbalances previously showed that platelet derived growth factor receptor alpha (PDGFRA) is the most frequent target of focal amplification in pediatric HGGs. To determine whether the PDGFRA is also targeted by more subtle mutations not detected by copy number analysis, we sequenced all PDGFRA coding exons from a cohort of pediatric HGGs. Somatic activating mutations were identified in 14.4% (13/90) of non-brainstem pediatric HGGs and 4.7% (2/43) of DIPGs, including missense mutations and in-frame deletions and insertions not previously described. 40% of tumors with mutation showed concurrent amplification, while 60% carried heterozygous mutations. Six different mutations impacting different domains all resulted in ligand-independent receptor activation that was blocked by small molecule inhibitors of PDGFR. Expression of mutants in p53-null primary mouse astrocytes conferred a proliferative advantage in vitro, and generated HGGs in vivo with complete penetrance when implanted into brain. The gene expression signatures reflected the spectrum of human diffuse HGGs. PDGFRA intragenic deletion of exons 8 and 9 were previously shown in adult HGG, but were not detected in 83 non-brainstem pediatric HGG and 57 DIPGs. Thus, a distinct spectrum of mutations confers constitutive receptor activation and oncogenic activity to PDGFR in childhood HGG. To better understand the consequence of PDGFRα mutation in pediatric gliomagenesis, retroviral constructs expressing wild-type PDGFRα or six selected PDGFRα mutants that affect different regions of the receptor were generated for functional studies. p53-null primary mouse astrocyte (PMA) cultures were chosen as a relevant cellular background to assess PDGFRα function.
2013-11-06 | E-GEOD-46190 | biostudies-arrayexpress
Project description:Pediatric diffuse midline gliomas harboring the Histone 3 lysine 27-to-methionine mutation (H3K27M-pDMG) represent a highly heterogenous group of brain tumors characterized by intrinsic resistance to radiation therapy, the current standard of care. Recent evidence suggests that intratumor small extracellular vesicle (sEV)-mediated signaling plays an oncogenic role among glioma stem cell populations. However, the dynamics and functional roles of H3K27M-pDMG derived sEVs in the context of radiation-induced stress remain unclear. In this study, we characterize sEV uptake dynamics between H3K27M tumor cells, identify potential sEV surface proteins involved in the process, and demonstrate that radioresistant (RR) H3K27M-pDMG-derived sEVs confer radioprotective effects to radiosensitive (RS) H3K27M-pDMG cells at the population level. RR-sEVs induce metabolic and gene expression changes in RS cell populations within the timescale of EV uptake and internalization, leading to improved DNA repair following radiation-induced stress. Furthermore, we identified the proteins, microRNAs (miRNAs), and metabolites present in RR-sEVs, shedding light on the molecular cargo that may be responsible for these effects. Our findings provide insights into the intrinsic radioresistant properties mediated by H3K27M-pDMG-derived sEVs and propose novel targets for disrupting radioresistant intratumoral communication in H3K27M-pDMGs.
2025-06-02 | GSE286941 | GEO
Project description:Pediatric diffuse midline gliomas harboring the Histone 3 lysine 27-to-methionine mutation (H3K27M-pDMG) represent a highly heterogenous group of brain tumors characterized by intrinsic resistance to radiation therapy, the current standard of care. Recent evidence suggests that intratumor small extracellular vesicle (sEV)-mediated signaling plays an oncogenic role among glioma stem cell populations. However, the dynamics and functional roles of H3K27M-pDMG derived sEVs in the context of radiation-induced stress remain unclear. In this study, we characterize sEV uptake dynamics between H3K27M tumor cells, identify potential sEV surface proteins involved in the process, and demonstrate that radioresistant (RR) H3K27M-pDMG-derived sEVs confer radioprotective effects to radiosensitive (RS) H3K27M-pDMG cells at the population level. RR-sEVs induce metabolic and gene expression changes in RS cell populations within the timescale of EV uptake and internalization, leading to improved DNA repair following radiation-induced stress. Furthermore, we identified the proteins, microRNAs (miRNAs), and metabolites present in RR-sEVs, shedding light on the molecular cargo that may be responsible for these effects. Our findings provide insights into the intrinsic radioresistant properties mediated by H3K27M-pDMG-derived sEVs and propose novel targets for disrupting radioresistant intratumoral communication in H3K27M-pDMGs.
2025-06-02 | GSE286943 | GEO