Neuro-oncology最新文献

Background: Diffuse Intrinsic Pontine Gliomas (DIPG) and other H3K27M-mutated diffuse midline gliomas (DMGs) are brain tumors that primarily affect children. Radiotherapy is the standard of care but only provides temporary symptomatic relief due to radioresistance. While hypoxia is a major driver of radioresistance in other tumors, there is no definitive evidence that DIPGs are hypoxic. DIPGs often contain histone mutations, which alter tumor metabolism and are also associated with radioresistance. Our objective was to identify the metabolic profiles of DIPG cells, detect hypoxia signatures, and uncover metabolism-linked mechanisms of radioresistance to improve tumor radiosensitivity.

Method: Using DIPG models combined with clinical datasets, we examined mitochondrial metabolism and signatures of hypoxia. We explored DIPG reliance on mitochondrial metabolism using extracellular flux assays and targeted metabolomics. In vitro and in vivo models were used to explore the mechanisms of targeting mitochondrial bioenergetics and hypoxia for radiosensitization. Treatment-induced transcriptomics and metabolomics were also investigated.

Results: Comprehensive analyses of DIPG cells show signatures of enhanced oxidative phosphorylation (OXPHOS). We also identified increased expression of specific OXPHOS related genes and signatures of hypoxia gene expression in datasets obtained from DIPG patients. We found the presence of hypoxia in orthotopic mouse models bearing DIPG tumors. These findings enabled us to develop a proof-of-concept treatment strategy to enhance radiosensitivity of DIPGs in vitro and in animal models.

Conclusion: DIPG cells rely on mitochondrial metabolism for growth, and targeting mitochondria disrupts bioenergetics, alleviates hypoxia, and enhances radiosensitivity. These findings warrant further exploration of OXPHOS inhibition as a radiosensitizing strategy for DIPG treatment.

Background: Epstein-Barr virus (EBV)+ and EBV- primary CNS lymphomas (PCNSL) carry distinct mutational landscapes, but their transcriptional and epigenetic profiles have not been integrated and compared. This precludes further insights into pathobiology and molecular differences, relevant for classification and targeted therapy.

Methods: 23 EBV- and 15 EBV+ PCNSL, histologically classified as diffuse large B-cell lymphomas, were subjected to RNA-Sequencing and EPIC methylation arrays. Unsupervised clustering analyses were performed. Differentially expressed and differentially methylated genes were identified and integrated.

Results: Two distinct transcriptional clusters were found, which separated EBV-and EBV+PCNSL (p < 0.0001). The EBV+ transcriptional signature contained genes (GPR15, FCER2/CD23, SLAMF1/CD150) closely regulated by EBV oncogenes in B-cells. Pathway enrichment analysis uncovered enhanced B-cell receptor (BCR) and WNT/beta-catenin signaling in EBV-lymphomas, whereas Interleukin-10, NOTCH, and viral life cycle pathways were upregulated in EBV+PCNSL. Correspondingly, BCR-associated SYK kinase activity was enriched in EBV-tumors while JAK2 was overrepresented in EBV+PCNSL. Epigenetic profiling revealed reduced global promoter methylation in EBV+PCNSL. Two methylation clusters were recognized, which separated EBV-and EBV+PCNSL (p < 0.0001). Epigenetic profiles were distinct from 2,788 other brain tumor and non-malignant reference samples. Promoter region hypermethylation of CD79B, a BCR subunit critical for sustained proliferation in EBV-disease, highly correlated (R = -0.7) with its transcriptional downregulation in EBV+PCNSL.

Conclusions: EBV+ and EBV- PCNSL harbor distinct transcriptional and epigenetic profiles, corroborating them as distinctive biological subtypes. Uncovered differences provide novel insights into their pathobiology, may guide molecular diagnostics and targeted therapies.

Meningiomas are the most common primary intracranial tumors of adults. For meningiomas that progress or recur despite surgical resection and radiotherapy, additional treatment options are limited due to lack of proven efficacy. Meningiomas show recurring molecular aberrations, which may serve as predictive markers for systemic pharmacotherapies with targeted drugs or immunotherapy, radiotherapy or radioligand therapy. Here, we review the evidence for a predictive role of a wide range of molecular alterations and markers including NF2, AKT1, SMO, SMARCE1, PIK3CA, CDKN2A/B, CDK4/6, TERT, TRAF7, BAP1, KLF4, ARID1/2, SUFU, PD-L1, SSTR2A, PR/ER, mTOR, VEGFR, PDGFR, as well as homologous recombination deficiency (HRD), genomic copy number variations, DNA methylation classes and combined gene expression profiles. In our assessment based on the established ESMO ESCAT (European Society for Medical Oncology Scale for Clinical Actionability of molecular Targets) evidence level criteria, no molecular target reached ESCAT I ("ready for clinical use") classification and only mTOR pathway activation and NF2 alterations reached ESCAT II ("investigational") classification, respectively. Our evaluations may guide targeted therapy selection in clinical practice and clinical trial efforts and highlight areas for which additional research is warranted.

Background: Inactivation of α-thalassaemia/mental retardation X-linked (ATRX) represents a defining molecular feature in large subsets of malignant glioma. ATRX deficiency gives rise to abnormal G-quadruplex (G4) DNA secondary structures, enhancing replication stress and genomic instability. Building on earlier work, we evaluated the extent to which pharmacological G4 stabilization selectively enhances DNA damage and cell death in ATRX-deficient preclinical glioma models.

Methods: Using the G4 stabilizer CX-5461, we treated patient-derived glioma stem cells (GSCs) in vitro and GSC flank and intracranial murine xenografts in vivo to evaluate efficacy as both a single agent and in combination with ionizing radiation (IR), the latter a central element of current treatment standards.

Results: CX-5461 promoted dose-sensitive lethality in ATRX-deficient GSCs relative to ATRX-intact controls. Mechanistic studies revealed that CX-5461 disrupted histone variant H3.3 deposition, enhanced replication stress and DNA damage, activated p53-independent apoptosis, and induced G2/M arrest to a greater extent in ATRX-deficient GSCs than in ATRX-intact counterparts. These data were corroborated in vivo, where CX-5461/IR treatment profoundly delayed tumor growth and prolonged survival in mice bearing ATRX-deficient flank xenografts. Histopathological analyses revealed decreased proliferation, increased apoptosis, and significant G4 induction, replication stress, and DNA damage in CX-5461-treated tumors, both alone and in combination with IR. Finally, despite suboptimal blood-brain-barrier penetration, systemic CX-5461 treatment induced tangible pharmacodynamic effects in ATRX-deficient intracranial GSC models.

Conclusions: In totality, our work substantively demonstrates efficacy and defines mechanisms of action for G4 stabilization as a novel therapeutic strategy targeting ATRX-deficient malignant glioma, laying the groundwork for clinical translation.

Background: Pediatric high-grade gliomas, such as diffuse midline glioma (DMG), have a poor prognosis and lack curative treatments. Current research models of DMG primarily rely on human DMG cell lines cultured in vitro or xenografted into the brains of immunodeficient mice. However, these models are insufficient to recapitulate the complex cell-cell interactions between DMG and the tumor immune microenvironment (TIME), therefore fall short of accurately reflecting how efficacious therapeutic agents or combinations will be in the clinical setting.

Methods: To address these challenges, we developed a neuroimmune-competent brain/tumor fusion organoid model system consisting entirely of human cells to investigate the interactions between DMG cells and the primary innate immune cells of the brain, microglia, in the TIME at both cellular and subcellular levels. We generated microglia-containing brain organoids (MiCBO) that carry morphologically mature, motile microglia and multiple subtypes of neurons to mimic the brain tumor microenvironment. These organoids were then fused with H3K27M mutant, TP53P27R/K132R DMG tumor spheroids to create the MiCBO-tumor fusion (MiCBO-TF) model.

Results: We utilized live imaging methods to simultaneously track the mobility of microglial cell bodies and the motility of their process, as well as the behavior of tumor cells within a human brain tissue environment. Our MiCBO-TF model faithfully recapitulated the diffuse infiltration pattern of DMG into brain tissue and revealed that microglial mobility and interactions with tumor cells are highly influenced by external factors and surrounding tissue environment.

Conclusions: The MiCBO-TF model represents a powerful platform for both mechanistic investigations and the development of precision medicine approaches for DMG.

Background: Despite recent advances in the biology of IDH-wildtype glioblastoma, it remains a devastating disease with median survival of less than 2 years. However, the molecular underpinnings of the heterogeneous response to the current standard-of-care treatment regimen consisting of maximal safe resection, adjuvant radiation, and chemotherapy with temozolomide remain unknown.

Methods: Comprehensive histopathologic, genomic, and epigenomic evaluation of paired initial and recurrent glioblastoma specimens from 106 patients was performed to investigate the molecular evolution and cellular phenotypes underlying differential treatment responses.

Results: While TERT promoter mutation and CDKN2A homozygous deletion were early events during gliomagenesis shared by initial and recurrent tumors, most other recurrent genetic alterations (eg, EGFR, PTEN, and NF1) were commonly private to initial or recurrent tumors indicating acquisition later during clonal evolution. Furthermore, glioblastomas exhibited heterogeneous epigenomic evolution with subsets becoming more globally hypermethylated, hypomethylated, or remaining stable. Glioblastoma that underwent sarcomatous transformation had shorter interval to recurrence and were significantly enriched in NF1, TP53, and RB1 alterations and the mesenchymal epigenetic class. Patients who developed somatic hypermutation following temozolomide treatment had significantly longer interval to disease recurrence and prolonged overall survival, and increased methylation at 4 specific CpG sites in the promoter region of MGMT was significantly associated with this development of hypermutation. Finally, an epigenomic evolution signature incorporating change in DNA methylation levels across 347 critical CpG sites was developed that significantly correlated with clinical outcomes.

Conclusions: Glioblastoma undergoes heterogeneous genetic, epigenetic, and cellular evolution that underlies prognostically different treatment responses.

Background: The outcome for pediatric patients with high-grade glioma (HGG) remains poor. Veliparib, a potent oral poly(adenosine diphosphate-ribose) polymerase (PARP) 1/2 inhibitor, enhances the activity of radiotherapy and DNA-damaging chemotherapy.

Methods: We conducted a single-arm, non-randomized phase 2 clinical trial to determine whether treatment with veliparib and radiotherapy, followed by veliparib and temozolomide, improves progression-free survival in pediatric patients with newly diagnosed HGG without H3 K27M or BRAF mutations compared to patient level data from historical cohorts with closely matching clinical and molecular features. Following surgical resection, newly diagnosed children with non-metastatic HGG were screened by rapid central pathology review and molecular testing. Eligible patients were enrolled on Stratum 1 (IDH wild-type) or Stratum 2 (IDH mutant).

Results: Both strata were closed to accrual for futility after planned interim analyses. Among the 23 eligible patients who enrolled on Stratum 1 and received protocol therapy, the 1-year event-free survival (EFS) was 23% (standard error, SE = 9%) and 1-year overall survival (OS) was 64% (SE = 10%). Among the 14 eligible patients who enrolled on Stratum 2 and received protocol therapy, the 1-year EFS was 57% (SE = 13%) and 1-year OS was 93% (SE = 0.7%).

Conclusions: Rapid central pathology review and molecular testing for eligibility was feasible. The protocol therapy including radiation, veliparib and temozolomide was well tolerated but failed to improve outcome compared to clinically and molecularly matched historical control cohorts treated with higher doses of alkylator chemotherapy.

Background: Recently, criteria based on amino acid positron emission tomography (PET) have been proposed for response assessment in diffuse gliomas (PET RANO 1.0). In this study, we compare the prevalence of measurable disease according to PET RANO 1.0 with magnetic resonance imaging (MRI)-based Response Assessment in Neuro-Oncology (RANO) criteria in glioblastoma.

Methods: We retrospectively identified patients with newly diagnosed IDH-wild-type glioblastoma who underwent [18F] Fluoroethyltyrosine (FET) PET and MRI after resection or biopsy and before radio-/radiochemotherapy. Two independent investigators analyzed measurable disease according to PET RANO 1.0 or MRI-RANO criteria. Additionally, lesion size, congruency patterns, and uptake intensity on [18F]FET PET images were assessed.

Results: We evaluated 125 patients including 49 cases after primary resection and 76 cases after biopsy. Using PET criteria, 113 out of 125 patients (90.4%) had measurable disease, with a median PET-positive volume of 15.34 cm3 (8.83-38.03). With MRI, a significantly lower proportion of patients had measurable disease (57/125, 45.6%; P < .001) with a median sum of maximum cross-sectional diameters of 35.65 mm (26.18-45.98). None of the 12 patients without measurable disease on PET had measurable disease on MRI. Contrariwise, 56/68 patients (82.4%) without measurable disease on MRI exhibited measurable disease on PET. Clinical performance status correlated significantly with PET-positive volume and MRI-based sum of diameters (P < .0059, P < .0087, respectively).

Conclusions: [18F]FET PET identifies a higher number of patients with measurable disease compared to conventional MRI in newly diagnosed glioblastoma. PET-based assessment may serve as a novel baseline parameter for evaluating residual tumor burden and improving patient stratification in glioblastoma studies. Further validation in prospective trials is warranted.

Background: Diffuse hemispheric glioma, H3G34R/V-mutant (DHG-H3G34) is characterized by poor prognosis and lack of effective treatment options. DHG-H3G34R further harbor deactivation of Alpha-Thalassemia/Mental Retardation Syndrome X-linked protein (ATRX; DHG-H3G34R_ATRX) suggesting a unique interaction of these two oncogenic alterations. In this study, we dissect their cell biological interplay, investigate the impact on telomere stabilization and, consequently, validate a targeted therapy approach.

Methods: We characterized patient-derived primary pediatric high-grade glioma (pHGG) models for telomere-maintenance mechanisms, DNA damage stress (including protein expression, pH2AX/Rad51 foci, cell-cycle arrest) and their sensitivity towards poly-ADP polymerase inhibitor (PARPi) combinations. Human induced pluripotent stem cells (iPSCs) were used for modelling the disease. The anticancer activity of PARPi combinations in vivo was studied in Chorioallantoic Membrane (CAM) and orthotopic in vivo experiments. Finally, we treated a DHG-H3G34R_ATRX patient with a PARPi combination therapy.

Results: We elaborate that alternative lengthening of telomeres (ALT) is a key characteristic of DHG-H3G34R_ATRX. A dominant cooperative effect between H3G34R and ATRX loss in ALT activation also became apparent in iPSCs, which endogenously exert telomerase activity. In both, patient-derived DHG-H3G34R_ATRX models and H3G34R+/ATRX- iPSCs, the ALT phenotype was associated with increased basal DNA damage stress, mediating synergistic susceptibility towards PARPi (talazoparib, niraparib) combinations with topoisomerase-I inhibitors (topotecan, irinotecan). In a first-of-its-kind case, treatment of a DHG-H3G34R_ATRX patient with the brain-penetrant PARP inhibitor niraparib and topotecan resulted in a significant tumor reduction.

Conclusion: Our preclinical and clinical data strongly support the further development of PARPis together with DNA damage stress-inducing treatment regimens for DHG-H3G34R_ATRX.