bims-malgli Biomed News
on Biology of malignant gliomas
Issue of 2024–09–15
fourteen papers selected by
Oltea Sampetrean, Keio University
  1. Hijacked macrophages sustain glioblastoma cells.
  2. Widespread Neuroanatomical Integration and Distinct Electrophysiological Properties of Glioma-Innervating Neurons.
  3. Glioblastoma induces the recruitment and differentiation of dendritic-like "hybrid" neutrophils from skull bone marrow.
  4. A patient-derived cell model for malignant transformation in IDH-mutant glioma.
  5. Fibrotic response to anti-CSF-1R therapy potentiates glioblastoma recurrence.
  6. Deep intravital brain tumor imaging enabled by tailored three-photon microscopy and analysis.
  7. Brain tumoroids: treatment prediction and drug development for brain tumors with fast, reproducible and easy-to-use personalized models.
  8. Integrated electrophysiological and genomic profiles of single cells reveal spiking tumor cells in human glioma.
  9. FDA approves first IDH-targeted glioma drug.
  10. Glioblastoma cells increase expression of notch signaling and synaptic genes within infiltrated brain tissue.
  11. Patient-derived tumor organoids mimic treatment-induced DNA damage response in glioblastoma.
  12. Integrated analyses reveal two molecularly and clinically distinct subtypes of H3 K27M-mutant diffuse midline gliomas with prognostic significance.
  13. H3K27M diffuse midline glioma is homologous recombination defective and sensitized to radiotherapy and NK cell-mediated antitumor immunity by PARP inhibition.
  14. Protocol to generate two distinct standard-of-care murine glioblastoma models for evaluating novel combination therapies.
  1. Nat Rev Neurol. 2024 Sep 12.
    Hijacked macrophages sustain glioblastoma cells.
    Ian Fyfe.
      
    DOI:  https://doi.org/10.1038/s41582-024-01018-x
  2. bioRxiv. 2024 Aug 26. pii: 2024.08.25.609573. [Epub ahead of print]
    Widespread Neuroanatomical Integration and Distinct Electrophysiological Properties of Glioma-Innervating Neurons.
    Annie L Hsieh, Sanika Ganesh, Tomasz Kula, Madiha Irshad, Emily Anne Ferenczi, Wengang Wang, Yi-Ching Chen, Song-Hua Hu, Zongyu Li, Shakchhi Joshi, Marcia C Haigis, Bernardo L Sabatini.
      Gliomas are the most common malignant primary brain tumors and are often associated with severe neurological deficits and mortality. Unlike many cancers, gliomas rarely metastasize outside the brain, indicating a possible dependency on unique features of brain microenvironment. Synapses between neurons and glioma cells exist, suggesting that glioma cells rely on neuronal inputs and synaptic signaling for proliferation. Yet, the locations and properties of neurons that innervate gliomas have remained elusive. In this study, we utilized transsynaptic tracing with a pseudotyped, glycoprotein-deleted rabies virus to specifically infect TVA and glycoprotein-expressing human glioblastoma cells in an orthotopic xenograft mouse model, allowing us to identify the neurons that form synapses onto the gliomas. Comprehensive whole-brain mapping revealed that these glioma-innervating neurons (GINs) consistently arise at brain regions, including diverse neuromodulatory centers and specific cortical layers, known to project to the glioma locations. Molecular profiling revealed that these long-range cortical GINs are predominantly glutamatergic, and subsets express both glutamatergic and GABAergic markers, whereas local striatal GINs are largely GABAergic. Electrophysiological studies demonstrated that while GINs share passive intrinsic properties with cortex-innervating neurons, their action potential waveforms are altered. Our study introduces a novel method for identifying and mapping GINs and reveals their consistent integration into existing location-dependent neuronal network involving diverse neurotransmitters and neuromodulators. The observed intrinsic electrophysiological differences in GINs lay the groundwork for future investigations into how these alterations may correspond with the postsynaptic characteristics of glioma cells.
    Significance: We have developed a novel system utilizing rabies virus-based monosynaptic tracing to directly visualize neurons that synapse onto human glioma cells implanted in mouse brain. This approach enables the mapping and quantitative analysis of these glioma-innervating neurons (GINs) in the entire mouse brain and overcomes previous barriers of molecular and electrophysiological analysis of these neurons due to the inability to identify them. Our findings indicate that GINs integrate into existing neural networks in a location-specific manner. Long-range GINs are mostly glutamatergic, with a subset expressing both glutamatergic and GABAergic markers and local striatal GINs are GABAergic, highlighting a complex neuromodulatory profile. Additionally, GINs exhibit unique action potential characteristics, distinct from similarly selected neurons in non-tumor-bearing brains. This study provides new insights into neuronal adaptations in response to forming putative synapses onto glioma, elucidating the intricate synaptic relationship between GINs and gliomas.
    DOI:  https://doi.org/10.1101/2024.08.25.609573
  3. Cancer Cell. 2024 Sep 09. pii: S1535-6108(24)00307-6. [Epub ahead of print]42(9): 1549-1569.e16
    Glioblastoma induces the recruitment and differentiation of dendritic-like "hybrid" neutrophils from skull bone marrow.
    Meeki Lad, Angad S Beniwal, Saket Jain, Poojan Shukla, Venina Kalistratova, Jangham Jung, Sumedh S Shah, Garima Yagnik, Atul Saha, Ankita Sati, Husam Babikir, Alan T Nguyen, Sabraj Gill, Jennifer Rios, Jacob S Young, Austin Lui, Diana Salha, Aaron Diaz, Manish K Aghi.
      Tumor-associated neutrophil (TAN) effects on glioblastoma (GBM) biology remain under-characterized. We show here that neutrophils with dendritic features-including morphological complexity, expression of antigen presentation genes, and the ability to process exogenous peptide and stimulate major histocompatibility complex (MHC)II-dependent T cell activation-accumulate intratumorally and suppress tumor growth in vivo. Trajectory analysis of patient TAN scRNA-seq identifies this "hybrid" dendritic-neutrophil phenotype as a polarization state that is distinct from canonical cytotoxic TANs, and which differentiates from local precursors. These hybrid-inducible immature neutrophils-which we identified in patient and murine glioblastomas-arise not from circulation, but from local skull marrow. Through labeled skull flap transplantation and targeted ablation, we characterize calvarial marrow as a contributor of antitumoral myeloid antigen-presenting cells (APCs), including TANs, which elicit T cell cytotoxicity and memory. As such, agents augmenting neutrophil egress from skull marrow-such as intracalvarial AMD3100, whose survival-prolonging effect in GBM we report-present therapeutic potential.
    Keywords:  MHC class II; T cells; antigen-presenting cells; dendritic cells; glioblastoma; myeloid; skull marrow; tumor-associated neutrophil
    DOI:  https://doi.org/10.1016/j.ccell.2024.08.008
  4. Acta Neuropathol Commun. 2024 Sep 10. 12(1): 148
    A patient-derived cell model for malignant transformation in IDH-mutant glioma.
    Olga Kim, Zach Sergi, Guangyang Yu, Kazutoshi Yamamoto, Martha Quezado, Zied Abdullaev, Danel R Crooks, Shun Kishimoto, Qi Li, Peng Lu, Burchelle Blackman, Thorkell Andresson, Xiaolin Wu, Bao Tran, Jun S Wei, Wei Zhang, Meili Zhang, Hua Song, Javed Khan, Murali C Krishna, Jeffrey R Brender, Jing Wu.
      Malignant transformation (MT) is commonly seen in IDH-mutant gliomas. There has been a growing research interest in revealing its underlying mechanisms and intervening prior to MT at the early stages of the transforming process. Here we established a unique pair of matched 3D cell models: 403L, derived from a low-grade glioma (LGG), and 403H, derived from a high-grade glioma (HGG), by utilizing IDH-mutant astrocytoma samples from the same patient when the tumor was diagnosed as WHO grade 2 (tumor mutational burden (TMB) of 3.96/Mb) and later as grade 4 (TMB of 70.07/Mb), respectively. Both cell models were authenticated to a patient's sample retaining endogenous expression of IDH1 R132H. DNA methylation profiles of the parental tumors referred to LGG and HGG IDH-mutant glioma clusters. The immunopositivity of SOX2, NESTIN, GFAP, OLIG2, and beta 3-Tubulin suggested the multilineage potential of both models. 403H was more prompt to cell invasion and developed infiltrative HGG in vivo. The differentially expressed genes (DEGs) from the RNA sequencing analysis revealed the tumor invasion and aggressiveness related genes exclusively upregulated in the 403H model. Pathway analysis showcased an enrichment of genes associated with epithelial-mesenchymal transition (EMT) and Notch signaling pathways in 403H and 403L, respectively. Mass spectrometry-based targeted metabolomics and hyperpolarized (HP) 1-13C pyruvate in-cell NMR analyses demonstrated significant alterations in the TCA cycle and fatty acid metabolism. Citrate, glutamine, and 2-HG levels were significantly higher in 403H. To our knowledge, this is the first report describing the development of a matched pair of 3D patient-derived cell models representative of MT and temozolomide (TMZ)-induced hypermutator phenotype (HMP) in IDH-mutant glioma, providing insights into genetic and metabolic changes during MT/HMP. This novel in vitro model allows further investigation of the mechanisms of MT at the cellular level.
    Keywords:  3D cell model; High-grade glioma (HGG); Hypermutator phenotype (HMP); IDH-mutant glioma; Low-grade glioma (LGG); Malignant transformation (MT); Matched patient-derived cells; Tumor mutational burden (TMB)
    DOI:  https://doi.org/10.1186/s40478-024-01860-6
  5. Cancer Cell. 2024 Sep 09. pii: S1535-6108(24)00311-8. [Epub ahead of print]42(9): 1507-1527.e11
    Fibrotic response to anti-CSF-1R therapy potentiates glioblastoma recurrence.
    Spencer S Watson, Anoek Zomer, Nadine Fournier, Joao Lourenco, Manfredo Quadroni, Agnieszka Chryplewicz, Sina Nassiri, Pauline Aubel, Simona Avanthay, Davide Croci, Erik Abels, Marike L D Broekman, Douglas Hanahan, Jason T Huse, Roy T Daniel, Monika E Hegi, Krisztian Homicsko, Giulia Cossu, Andreas F Hottinger, Johanna A Joyce.
      Glioblastoma recurrence is currently inevitable despite extensive standard-of-care treatment. In preclinical studies, an alternative strategy of targeting tumor-associated macrophages and microglia through CSF-1R inhibition was previously found to regress established tumors and significantly increase overall survival. However, recurrences developed in ∼50% of mice in long-term studies, which were consistently associated with fibrotic scars. This fibrotic response is observed following multiple anti-glioma therapies in different preclinical models herein and in patient recurrence samples. Multi-omics analyses of the post-treatment tumor microenvironment identified fibrotic areas as pro-tumor survival niches that encapsulated surviving glioma cells, promoted dormancy, and inhibited immune surveillance. The fibrotic treatment response was mediated by perivascular-derived fibroblast-like cells via activation by transforming growth factor β (TGF-β) signaling and neuroinflammation. Concordantly, combinatorial inhibition of these pathways inhibited treatment-associated fibrosis, and significantly improved survival in preclinical trials of anti-colony-stimulating factor-1 receptor (CSF-1R) therapy.
    DOI:  https://doi.org/10.1016/j.ccell.2024.08.012
  6. Nat Commun. 2024 Sep 10. 15(1): 7383
    Deep intravital brain tumor imaging enabled by tailored three-photon microscopy and analysis.
    Marc Cicero Schubert, Stella Judith Soyka, Amr Tamimi, Emanuel Maus, Julian Schroers, Niklas Wißmann, Ekin Reyhan, Svenja Kristin Tetzlaff, Yvonne Yang, Robert Denninger, Robin Peretzke, Carlo Beretta, Michael Drumm, Alina Heuer, Verena Buchert, Alicia Steffens, Jordain Walshon, Kathleen McCortney, Sabine Heiland, Martin Bendszus, Peter Neher, Anna Golebiewska, Wolfgang Wick, Frank Winkler, Michael O Breckwoldt, Anna Kreshuk, Thomas Kuner, Craig Horbinski, Felix Tobias Kurz, Robert Prevedel, Varun Venkataramani.
      Intravital 2P-microscopy enables the longitudinal study of brain tumor biology in superficial mouse cortex layers. Intravital microscopy of the white matter, an important route of glioblastoma invasion and recurrence, has not been feasible, due to low signal-to-noise ratios and insufficient spatiotemporal resolution. Here, we present an intravital microscopy and artificial intelligence-based analysis workflow (Deep3P) that enables longitudinal deep imaging of glioblastoma up to a depth of 1.2 mm. We find that perivascular invasion is the preferred invasion route into the corpus callosum and uncover two vascular mechanisms of glioblastoma migration in the white matter. Furthermore, we observe morphological changes after white matter infiltration, a potential basis of an imaging biomarker during early glioblastoma colonization. Taken together, Deep3P allows for a non-invasive intravital investigation of brain tumor biology and its tumor microenvironment at subcortical depths explored, opening up opportunities for studying the neuroscience of brain tumors and other model systems.
    DOI:  https://doi.org/10.1038/s41467-024-51432-4
  7. Neuro Oncol. 2024 Sep 10. pii: noae184. [Epub ahead of print]
    Brain tumoroids: treatment prediction and drug development for brain tumors with fast, reproducible and easy-to-use personalized models.
    Aurélie Soubéran, Carine Jiguet-Jiglaire, Soline Toutain, Philippe Morando, Nathalie Baeza-Kallee, Romain Appay, Céline Boucard, Thomas Graillon, Mikael Meyer, Kaissar Farah, Dominique Figarella-Branger, Emeline Tabouret, Aurélie Tchoghandjian.
       BACKGROUND: generation of patient avatar is critically needed in neuro-oncology for treatment prediction and preclinical therapeutic development. Our objective was to develop a fast, reproducible, low-cost and easy-to-use method of tumoroids generation and analysis, efficient for all types of brain tumors, primary and metastatic.
    METHODS: tumoroids were generated from 89 patients: 81 primary tumors including 77 gliomas, and 8 brain metastases. Tumoroids morphology, cellular and molecular characteristics were compared with the ones of the parental tumor by using histology, methylome profiling, pTERT mutations and multiplexed spatial immunofluorescences. Their cellular stability overtime was validated by flow cytometry. Therapeutic sensitivity was evaluated and predictive factors of tumoroid generation were analyzed.
    RESULTS: All the tumoroids analyzed had similar histological (N=21) and molecular features (N=7) than the parental tumor. Median generation time was 5 days. Success rate was 65 %: it was higher for high grade gliomas and brain metastases versus IDH mutated low grade gliomas. For high-grade gliomas, neither other clinical, neuro-imaging, histological nor molecular factors were predictive of tumoroid generation success. The cellular organization inside tumoroids analyzed by MACSima revealed territories dedicated to specific cell subtypes. Finally, we showed the correlation between tumoroid and patient treatment responses to radio-chemotherapy and their ability to respond to immunotherapy thanks to a dedicated and reproducible 3D analysis workflow.
    CONCLUSION: patient-derived tumoroid model that we developed offers a robust, user-friendly, low-cost and reproducible preclinical model valuable for therapeutic development of all type of primary or metastatic brain tumors, allowing their integration into forthcoming early-phase clinical trials.
    Keywords:  brain metastasis; brain tumor; glioma; patient avatar; tumoroid
    DOI:  https://doi.org/10.1093/neuonc/noae184
  8. Cancer Cell. 2024 Aug 24. pii: S1535-6108(24)00308-8. [Epub ahead of print]
    Integrated electrophysiological and genomic profiles of single cells reveal spiking tumor cells in human glioma.
    Rachel N Curry, Qianqian Ma, Malcolm F McDonald, Yeunjung Ko, Snigdha Srivastava, Pey-Shyuan Chin, Peihao He, Brittney Lozzi, Prazwal Athukuri, Junzhan Jing, Su Wang, Arif O Harmanci, Benjamin Arenkiel, Xiaolong Jiang, Benjamin Deneen, Ganesh Rao, Akdes Serin Harmanci.
      Prior studies have described the complex interplay that exists between glioma cells and neurons; however, the electrophysiological properties endogenous to glioma cells remain obscure. To address this, we employed Patch-sequencing (Patch-seq) on human glioma specimens and found that one-third of patched cells in IDH mutant (IDHmut) tumors demonstrate properties of both neurons and glia. To define these hybrid cells (HCs), which fire single, short action potentials, and discern if they are of tumoral origin, we developed the single cell rule association mining (SCRAM) computational tool to annotate each cell individually. SCRAM revealed that HCs possess select features of GABAergic neurons and oligodendrocyte precursor cells, and include both tumor and non-tumor cells. These studies characterize the combined electrophysiological and molecular properties of human glioma cells and describe a cell type in human glioma with unique electrophysiological and transcriptomic properties that may also exist in the non-tumor brain.
    Keywords:  GABAergic neurons; Patch-seq; action potentials; glioma; machine learning; oligodendrocyte precursor cells; scRNA-seq
    DOI:  https://doi.org/10.1016/j.ccell.2024.08.009
  9. Nat Biotechnol. 2024 Sep;42(9): 1325
    FDA approves first IDH-targeted glioma drug.
      
    DOI:  https://doi.org/10.1038/s41587-024-02408-8
  10. Nat Commun. 2024 Sep 09. 15(1): 7857
    Glioblastoma cells increase expression of notch signaling and synaptic genes within infiltrated brain tissue.
    Dylan Scott Lykke Harwood, Vilde Pedersen, Nicolai Schou Bager, Ane Yde Schmidt, Tobias Overlund Stannius, Aušrinė Areškevičiūtė, Knud Josefsen, Dorte Schou Nørøxe, David Scheie, Hannah Rostalski, Maya Jeje Schuang Lü, Alessio Locallo, Ulrik Lassen, Frederik Otzen Bagger, Joachim Weischenfeldt, Dieter Henrik Heiland, Kristoffer Vitting-Seerup, Signe Regner Michaelsen, Bjarne Winther Kristensen.
      Glioblastoma remains one of the deadliest brain malignancies. First-line therapy consists of maximal surgical tumor resection, accompanied by chemotherapy and radiotherapy. Malignant cells escape surgical resection by migrating into the surrounding healthy brain tissue, where they give rise to the recurrent tumor. Based on gene expression, tumor cores can be subtyped into mesenchymal, proneural, and classical tumors, each being associated with differences in genetic alterations and cellular composition. In contrast, the adjacent brain parenchyma where infiltrating malignant cells escape surgical resection is less characterized in patients. Using spatial transcriptomics (n = 11), we show that malignant cells within proneural or mesenchymal tumor cores display spatially organized differences in gene expression, although such differences decrease within the infiltrated brain tissue. Malignant cells residing in infiltrated brain tissue have increased expression of genes related to neurodevelopmental pathways and glial cell differentiation. Our findings provide an updated view of the spatial landscape of glioblastomas and further our understanding of the malignant cells that infiltrate the healthy brain, providing new avenues for the targeted therapy of these cells after surgical resection.
    DOI:  https://doi.org/10.1038/s41467-024-52167-y
  11. iScience. 2024 Sep 20. 27(9): 110604
    Patient-derived tumor organoids mimic treatment-induced DNA damage response in glioblastoma.
    Bernarda Majc, Anamarija Habič, Marta Malavolta, Miloš Vittori, Andrej Porčnik, Roman Bošnjak, Jernej Mlakar, Alenka Matjašič, Andrej Zupan, Marija Skoblar Vidmar, Tamara Lah Turnšek, Aleksander Sadikov, Barbara Breznik, Metka Novak.
      Glioblastoma (GB) is the most common primary malignant brain tumor, characterized by resistance to therapy. Despite aggressive treatment options, GB remains an incurable disease. Invasiveness and heterogeneity are key GB features that cannot be studied in preclinical in vitro models. In this study, we investigated the effects of standard therapy using patient-derived GB organoids (GBOs). GBOs reflect the complexity and heterogeneity of the original tumor tissue. No significant effect on GBO viability or invasion was observed after irradiation and temozolomide treatment. E3 ubiquitin-protein ligase (MDM2), cyclin-dependent kinase inhibitor 1A (CDKN1A), and the serine/threonine kinases ATM and ATR were upregulated at the gene and protein levels after treatment. Our results show that the p53 pathway and DNA-damage response mechanisms were triggered, suggesting that GBOs recapitulate GB therapy resistance. GBOs thus provide a highly efficient platform to assess the specific responses of GB patients to therapy and to further explore therapy resistance.
    Keywords:  cancer; cellular physiology; cellular toxicology; in vitro toxicology including 3D culture; technical aspects of cell biology
    DOI:  https://doi.org/10.1016/j.isci.2024.110604
  12. Acta Neuropathol. 2024 Sep 10. 148(1): 40
    Integrated analyses reveal two molecularly and clinically distinct subtypes of H3 K27M-mutant diffuse midline gliomas with prognostic significance.
    Lotte Stegat, Alicia Eckhardt, Antonia Gocke, Sina Neyazi, Lara Pohl, Simone Schmid, Matthias Dottermusch, Stephan Frank, Hans Pinnschmidt, Jochen Herms, Markus Glatzel, Matija Snuderl, Leonille Schweizer, Christian Thomas, Julia Neumann, Mario M Dorostkar, Ulrich Schüller, Annika K Wefers.
      H3 K27M-altered diffuse midline gliomas (DMGs) are highly malignant tumours that arise in the midline structures of the CNS. Most DMGs carry an H3 K27M-mutation in one of the genes encoding for histone H3. Recent studies suggested that epigenetic subgroups of DMGs can be distinguished based on alterations in the MAPK-signalling pathway, tumour localisation, mutant H3-gene, or overall survival (OS). However, as these parameters were studied individually, it is unclear how they collectively influence survival. Hence, we analysed dependencies between different parameters, to define novel epigenetic, clinically meaningful subgroups of DMGs. We collected a multifaceted cohort of 149 H3 K27M-mutant DMGs, also incorporating data of published cases. DMGs were included in the study if they could be clearly allocated to the spinal cord (n = 31; one patient with an additional sellar tumour), medulla (n = 20), pons (n = 64) or thalamus (n = 33), irrespective of further known characteristics. We then performed global genome-wide DNA methylation profiling and, for a subset, DNA sequencing and survival analyses. Unsupervised hierarchical clustering of DNA methylation data indicated two clusters of DMGs, i.e. subtypes DMG-A and DMG-B. These subtypes differed in mutational spectrum, tumour localisation, age at diagnosis and overall survival. DMG-A was enriched for DMGs with MAPK-mutations, medullary localisation and adult age. 13% of DMG-A had a methylated MGMT promoter. Contrarily, DMG-B was enriched for cases with TP53-mutations, PDGFRA-amplifications, pontine localisation and paediatric patients. In univariate analyses, the features enriched in DMG-B were associated with a poorer survival. However, all significant parameters tested were dependent on the cluster attribution, which had the largest effect on survival: DMG-A had a significantly better survival compared to DMG-B (p < 0.001). Hence, the subtype attribution based on two methylation clusters can be used to predict survival as it integrates different molecular and clinical parameters.
    Keywords:  DNA methylation analyses; Diffuse midline glioma; Mutations; Survival
    DOI:  https://doi.org/10.1007/s00401-024-02800-3
  13. bioRxiv. 2024 Aug 27. pii: 2024.08.26.609803. [Epub ahead of print]
    H3K27M diffuse midline glioma is homologous recombination defective and sensitized to radiotherapy and NK cell-mediated antitumor immunity by PARP inhibition.
    Yupei Guo, Zian Li, Leslie A Parsels, Zhuwen Wang, Joshua D Parsels, Anushka Dalvi, Stephanie The, Nan Hu, Victoria M Valvo, Robert Doherty, Erik Peterson, Xinjun Wang, Sujatha Venkataraman, Sameer Agnihotri, Sriram Venneti, Daniel R Wahl, Michael D Green, Theodore S Lawrence, Carl Koschmann, Meredith A Morgan, Qiang Zhang.
       Background: Radiotherapy (RT) is the primary treatment for diffuse midline glioma (DMG), a lethal pediatric malignancy defined by histone H3 lysine 27-to-methionine (H3K27M) mutation. Based on the loss of H3K27 trimethylation producing broad epigenomic alterations, we hypothesized that H3K27M causes a functional double-strand break (DSB) repair defect that could be leveraged therapeutically with PARP inhibitor and RT for selective radiosensitization and antitumor immune responses.
    Methods: H3K27M isogenic DMG cells and orthotopic brainstem DMG tumors in immune deficient and syngeneic, immune competent mice were used to evaluate the efficacy and mechanisms of PARP1/2 inhibition by olaparib or PARP1 inhibition by AZD9574 with concurrent RT.
    Results: H3K27M mutation caused an HRR defect characterized by impaired RT-induced K63-linked polyubiquitination of histone H1 and inhibition of HRR protein recruitment. H3K27M DMG cells were selectively radiosensitized by olaparib in comparison to isogenic controls, and this effect translated to efficacy in H3K27M orthotopic brainstem tumors. Olaparib and RT induced an innate immune response and induction of NK cell (NKG2D) activating ligands leading to increased NK cell-mediated lysis of DMG tumor cells. In immunocompetent syngeneic orthotopic DMG tumors, either olaparib or AZD9574 in combination with RT enhanced intratumoral NK cell infiltration and activity in association with NK cell-mediated therapeutic responses and favorable activity of AZD9574.
    Conclusions: The HRR deficiency in H3K27M DMG can be therapeutically leveraged with PARP inhibitors to radiosensitize and induce an NK cell-mediated antitumor immune response selectively in H3K27M DMG, supporting the clinical investigation of best-in-class PARP inhibitors with RT in DMG patients.
    Key points: H3K27M DMG are HRR defective and selectively radiosensitized by PARP inhibitor.PARP inhibitor with RT enhances NKG2D ligand expression and NK cell-mediated lysis.NK cells are required for the therapeutic efficacy of PARP inhibitor and RT.
    Importance of the Study: Radiotherapy is the cornerstone of H3K27M-mutant diffuse midline glioma treatment, but almost all patients succumb to tumor recurrence with poor overall survival, underscoring the need for RT-based precision combination therapy. Here, we reveal HRR deficiency as an H3K27M-mediated vulnerability and identify a novel mechanism linking impaired RT-induced histone H1 polyubiquitination and the subsequent RNF168/BRCA1/RAD51 recruitment in H3K27M DMG. This model is supported by selective radiosensitization of H3K27M DMG by PARP inhibitor. Notably, the combination treatment results in NKG2D ligand expression that confers susceptibility to NK cell killing in H3K27M DMG. We also show that the novel brain penetrant, PARP1-selective inhibitor AZD9574 compares favorably to olaparib when combined with RT, prolonging survival in a syngeneic orthotopic model of H3K27M DMG. This study highlights the ability of PARP1 inhibition to radiosensitize and induce an NK cell-mediated antitumor immunity in H3K27M DMG and supports future clinical investigation.
    DOI:  https://doi.org/10.1101/2024.08.26.609803
  14. STAR Protoc. 2024 Sep 11. pii: S2666-1667(24)00469-6. [Epub ahead of print]5(3): 103304
    Protocol to generate two distinct standard-of-care murine glioblastoma models for evaluating novel combination therapies.
    Raphael Pineau, Pierre Jean Le Reste, Tony Avril, Ulrich Jarry, Eric Chevet, Diana Pelizzari-Raymundo.
      In cancer research, murine models play a crucial role as highly valuable preclinical tools. Here, we present a protocol to generate a murine model of glioblastoma through the direct intracranial injection of tumor cells. We describe steps for cell culture, intracranial implantation, and standard-of-care treatments. We then detail procedures for monitoring tumor growth using bioluminescent imaging. For complete details on the use and execution of this protocol, please refer to Pelizzari-Raymundo et al.1.
    Keywords:  cancer; cell culture; model organisms; molecular biology
    DOI:  https://doi.org/10.1016/j.xpro.2024.103304
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