tbuckley/cabot-search huggingface dataset:
CNSC-25. CONCURRENT IMMUNE CHECKPOINT BLOCKADE ENHANCES THE SURVIVAL BENEFIT OF CLINICALLY RELEVANT MAPK PATHWAY INHIBITORS IN A T CELL-DEPENDENT MANNER
Authors: Yao Lulu Xing, Jong-Whi Park, Stefan Grossauer, Dena Panovska, Brandon Bui, Daniella Morales, Jeffrey Nirschl, Zhi-Ping Feng, Wes Anderson, Jean Mulcahy Levy, Karisa Schreck, Laura Prolo, Dolores Hambardzymyan, Claudia Petritsch
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Despite the availability of targeted therapies, gliomas carrying the BRAFV600E mutation remain challenging to treat. Combined pharmacologic BRAFV600E and MEK inhibition is clinically used in patients with BRAFV600E mutant gliomas, but primary and acquired resistance is reported in ~70% of high-grade glioma patients. OBJECTIVES To gain mechanistic insights into therapy adaptation and escape for developing combination therapies that enhance clinical effects of combined BRAFV600E inhibition with Dabrafenib and MEK inhibition with Trametinib (BRAFi+MEKi) in high-grade gliomas. APPROACH Patients’ pre- and post-treatment glioma tissues, patient-derived and mouse cell lines, and two novel immunocompetent mouse models for BRAFV600E mutant high-grade gliomas were analyzed for the effect of BRAFi+MEKi using a range of techniques including bulk and single-cell RNA sequencing, immunofluorescence staining, flow cytometry, and mass cytometry. RESULTS We present new data showing that the BRAFi+MEKi combination significantly reduced glioma cell viability while inducing glial differentiation programs, potentially associated with programmed death receptor (PD-1) signaling. This suggests a profound shift in the glioma cell differentiation state that is linked to an inclination toward T cell inhibition. This prompted us to combine BRAFi+MEKi with immune checkpoint inhibitors targeting PD-L1 and CTLA-4, which significantly decreased T cell inhibition. Furthermore, from mouse studies, this combination therapy conferred a survival benefit over single BRAFi+MEKi combination therapy alone. Additionally, BRAFi+MEKi treatment triggered an interferon-gamma response, indicative of cytotoxicity, and enhanced the expression of MHC molecules associated with antigen presentation, only in drug-sensitive but not drug-resistant gliomas. The lack of improved therapeutic efficacy of immune checkpoint blockade in athymic mice, which lack T cells, emphasized the critical role of T cell activity in driving the success of the combination treatment. CLINICAL IMPACT Our preclinical findings highlight the potential of concurrent BRAFi+MEKi treatment and immune checkpoint blockade for overcoming therapy resistance in BRAF mutant high-grade glioma patients.
EPCO-04. H3F3A K27M MUTATION DRIVES A REPRESSIVE TRANSCRIPTOME VIA REDUCED SERINE 31 PHOSPHORYLATION BY MODULATING CHROMATIN ACCESSIBILITY, INDEPENDENT OF H3K27ME3 IN DIFFUSE MIDLINE GLIOMA
Authors: Suraj Bhattarai, Charles Day, Faruck Hakkim, Florina Grigore, Alyssa Langfald, Edward Hinchcliffe, James Robinson
Journal: Neuro-Oncology (2024)

Abstract Heterozygous H3.3 K27M mutations are central to the pathogenesis of diffuse midline gliomas (DMG), causing a global reduction in H3K27 trimethylation (H3K27me3) and subsequent epigenetic dysregulation. H3.3 contains a unique Serine 31 (S31) phosphorylation site crucial for mitotic checkpoint regulation. In DMG cells, reduced mitotic S31 phosphorylation correlates with chromosomal instability and aneuploidy. Using a mouse model, we demonstrate that both H3.3K27M and H3.3S31A mutations promote high-grade glioma development, whereas wild-type H3.3 does not. Importantly, S31A, which maintains normal K27me, suggests that S31 phosphorylation loss alone is oncogenic. The H3.3K27M mutation disrupts epigenetic regulation by inhibiting the Polycomb Repressive Complex 2 (PRC2), leading to decreased H3K27me3 and unintended gene induction. Concurrently, K27M exerts a compensatory repressive effect on the transcriptome, mediated by reduced S31 phosphorylation, independent of PRC2 activity. Using CRISPR-engineered isogenic DMG cells and analyzing the transcriptome and chromatin accessibility with RNA-seq and ATAC-seq, we found that the K27M mutation produces a balanced gene expression profile, while PRC2 loss primarily leads to gene induction. Notably, cells with S31A mutations also maintain this balanced profile, linking the PRC2-independent effect of K27M to reduced S31 phosphorylation. Conversely, cells with wild-type K27 but S31A mutation show a repressive genomic state, evidenced by an up/down gene ratio of 0.75, owing to functional PRC2. We further show that the genes uniquely dysregulated by K27M or S31A, independent of PRC2, overlap significantly, with dysregulated genes displaying altered chromatin accessibility. This suggests that the effect of K27M and S31A mutations on gene regulation is primarily due to changes in chromatin state. This complex interplay points to targeting K27M-associated pathways, particularly S31 phosphorylation, as a promising therapeutic avenue in DMG, a malignancy with fewer effective treatments and dismal prognosis.
RADT-40. EVALUATION OF SMALLER CLINICAL TARGET VOLUMES AND PATTERNS OF PROGRESSION IN PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA TO INFORM FUTURE DIRECTIONS IN RADIATION TREATMENT PLANNING
Authors: Jordan Hill, Yujue Tan, Michael Tjong, Gilbert Youssef, Ayal Aizer, Shyam Tanguturi, Diana Shi, Daphne Haas-Kogan, Raymond Huang, Patrick Wen, Rifaquat Rahman
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND NRG Oncology Group guidelines recommend a clinical target volume (CTV) including generous expansions and incorporation of T2/FLAIR to account for potential tumor infiltration for glioblastoma patients, though smaller CTV expansions may be feasible. We retrospectively reviewed a large cohort of GBM patients to characterize patterns of recurrence and to assess the potential for smaller CTV margins. METHODS 312 consecutive adult patients with histologically confirmed diagnosis of glioblastoma treated with radiation therapy and temozolomide at a single institution were included in this study. All relevant clinical and pathological data was retrieved from local electronic medical records. MRIs from four timepoints 1) Pre-operative, 2) post-operative, 3) post-radiation and 4) time of progression were reviewed and fused with each other with rigid registration. We created a gross tumor volume including the resection cavity and residual enhancing tumor (GTV-GAD) and a GTV which included the GAD-GTV and pre-radiation T2/FLAIR signal (GTV-FLAIR). Multiple CTV expansions were applied to the GAD-GTV and FLAIR-GTV to evaluate coverage of subsequent progressive disease. RESULTS We evaluated 312 patients with a median age of 59.8 (range 20-93), 59% male, 61% KPS ≥ 90, 49% underwent gross total resection (51% subtotal resection/biopsy), 43% methylated and 57% unmethylated. CTV expansions of 2 cm, 1.5 cm, 1 cm, 0.5 cm, and 0 cm from GTV-GAD would have covered the epicenter of recurrent tumor in 90.7%, 88.1%, 84.6%, 77.5%, and 53.5% of cases respectively. CTV expansions from GTV-FLAIR of 2 cm, 1.5 cm, 1 cm, 0.5 cm, and 0 cm would have covered the epicenter of recurrent tumor in 93.5%, 92.6%, 91.3%, 88.1%, and 78.8% of cases respectively. On multivariable analysis, GAD-GTV and FLAIR-GTV volume were not associated with progression-free or overall survival(P&amp;gt;0.05). CONCLUSION Based upon our analysis, smaller treatment volumes could represent an opportunity to reduce treatment-related morbidity without compromising clinical outcomes.
TMET-16. GABA PRODUCTION INDUCED BY IMIPRIDONES IS A TARGETABLE AND IMAGEABLE METABOLIC ALTERATION IN DIFFUSE MIDLINE GLIOMAS
Authors: Georgios Batsios, Suresh Udutha, Celine Taglang, Anne Marie Gillespie, Benison Lau, Sunjong Ji, Timothy Phoenix, Sabine Mueller, Sriram Venneti, Carl Koschmann, Pavithra Viswanath
Journal: Neuro-Oncology (2024)

Abstract Diffuse midline gliomas (DMGs) are lethal brain tumors in children. The imipridones ONC201 and ONC206 have emerged as promising therapies for DMG patients, but efficacy as monotherapy is limited. Another hurdle is the lack of biomarkers that report on drug-target engagement at an early timepoint after treatment. Here, using 1H-magnetic resonance spectroscopy (1H-MRS), which is a non-invasive method of quantifying metabolite pool sizes, we show that imipridones induce accumulation of gamma-aminobutyric acid (GABA) in patient-derived (BT245, SF8628) and syngeneic (26-B7, 26-C2) cells. Importantly, in vivo1H-MRS detects a significant increase in GABA within a week of ONC206 treatment, when anatomical alterations are absent, in mice bearing orthotopic BT245, SF8628 or 26-B7 xenografts. Mechanistic studies show that imipridones activate the mitochondrial protease ClpP and upregulate the stress-responsive transcription factor ATF4. ATF4, in turn, upregulates glutamate decarboxylase, the enzyme that synthesizes GABA, and downregulates GABA transaminase, which degrades GABA, leading to GABA accumulation in DMG cells and orthotopic tumors. Since GABA is known to regulate oxidative stress signaling and since imipridones induce oxidative stress, we assessed whether GABA influences oxidative stress in DMG cells. Our studies indicate that GABA induces expression of superoxide dismutase (SOD1), which scavenges superoxide radicals and, thereby, curbs apoptosis induced by imipridones. The biological effects of GABA are mediated via signaling cascades triggered by GABA receptors and we find that GABA acts in an autocrine manner via the GABAB receptor to upregulate SOD1. Importantly, the clinically translatable GABAB receptor antagonist SGS742 and the SOD1 inhibitor ATN-224 exacerbate oxidative stress and synergistically induce apoptosis in combination with imipridones in DMG cells. Furthermore, SGS742 is brain-penetrant and potentiates ONC206-induced apoptosis in mice bearing orthotopic SF8628 xenografts in vivo. Collectively, we identify GABA as a unique metabolic adaptation to imipridones that can be leveraged for imaging drug-target engagement and for enhancing response to therapy. Clinical translation of our studies will enable precision therapy and imaging for DMG patients.
EPCO-34. DECIPHERING THE LONGITUDINAL TRAJECTORIES OF GLIOBLASTOMA BY INTEGRATIVE SINGLE-CELL GENOMICS
Authors: Avishay Spitzer, Kevin C Johnson, Masashi Nomura, Luciano Garofano, Djamel Nehar-belaid, Noam Galili Darnell, Alissa C Greenwald, Lillian Bussema, Young Taek Oh, Frederick S Varn, Fulvio D’Angelo, Simon Gritsch, Kevin J Anderson, Simona Migliozzi, L Nicolas Gonzalez Castro, Tamrin Chowdhury, Nicolas Robine, Catherine Reeves, Jong Bae Park, Anuja Lipsa, Frank Hertel, Anna Golebiewska, Simone P Niclou, Labeeba Nusrat, Sorcha Kellet, Sunit Das, Hyo-Eun Moon, Sun Ha Paek, Franck Bielle, Alice Laurenge, Anna Luisa Di Stefano, Bertrand Mathon, Alberto Picca, Marc Sanson, Shota Tanaka, Nobuhito Saito, David M Ashley, Stephen T Keir, Jason T Huse, W K Alfred Yung, Anna Lasorella, Antonio Iavarone, Roel G W Verhaak, Itay Tirosh, Mario L Suvà
Journal: Neuro-Oncology (2024)

Abstract The evolution of cellular heterogeneity in IDH-wildtype glioblastoma (GBM) after standard-of-care therapy remains poorly understood. To address it, we assembled a longitudinal cohort of 121 primary and recurrent GBM specimens from 59 patients, with extensive clinical annotations, and profiled it by single-nucleus RNA-sequencing and bulk tumor DNA sequencing. In most cases, longitudinal samples diverged in their composition of cell types and cell states. However, almost all theoretical trajectories were observed in our cohort such that the overall distribution of cell types and cell states was comparable between primary and recurrent samples. The most consistent longitudinal effect (66% of patients) was a lower malignant cell fraction at recurrence and a reciprocal increase in proportions of glio-neuronal TME cell types; in some cases, this was further accompanied by a coordinated shift of malignant cells towards neuronal-like states. MGMT methylation and radiation-related small deletion phenotypes were linked to particular trajectories, with depletion of mesenchymal-like cells and enrichment of hypoxia-related malignant cells, respectively. Importantly, changes in malignant states were also associated with specific changes in TME composition. In summary, our analysis highlights diverse longitudinal GBM trajectories that are shaped by treatment response and TME interactions.
CSIG-10. DEFINING THE ROLE OF EZHIP ON CHROMOSOMAL INSTABILITY IN EPENDYMOMA
Authors: Lukmanul Hakkim Faruck
Journal: Neuro-Oncology (2024)

Abstract Diffuse Midline Gliomas (DMGs) are highly aggressive pediatric cancers with no effective treatments. Over 80% of DMGs harbor histone mutations, particularly H3.1 K27M, H3.3 K27M, and H3.3 G34R/V. These mutations impair the function of the Polycomb Repressive Complex 2 (PRC2), leading to reduced levels of H3K27me3. Overexpression of the EZHIP has been identified in ependymomas and DMGs. EZHIP overexpression is marked by widespread H3K27me3 loss and is mutually exclusive with histone mutations. EZHIP overexpression mimics the effects of the H3K27M mutation by reducing H3K27me3 levels. It is believed to inhibit the catalytic activity of EZH2 by binding to its SET domain, similar to the K27M mutant. Expression of EZHIP is tightly regulated and typically absent in most cell types. The transcriptional regulation of EZHIP is poorly understood; however, promoter hypermethylation is likely involved in regulating its expression. We investigate EZHIP’s role in DMG tumorigenesis, focusing on its regulation, impact on histone modifications, and chromosomal stability. Initial analyses have revealed transcription factor binding sites within the EZHIP promoter, including EGR2, SOX2, and ICP4, indicating that various transcription factors and viral infections might directly affect EZHIP expression. Utilizing RNA-Seq, we have identified both shared and unique transcriptomic alterations in DMG cells related to EZHIP expression and H3.3 K27M mutations. To study the role of EZHIP in tumorigenesis, we developed a mouse model expressing EZHIP-HA p2A PDFGB in RCAS-Nestin TVA mice. EZHIP expression induces high-grade tumors and significantly reduces survival. Our ongoing research suggests that EZHIP functions similarly to H3.3 K27M mutations in driving tumor growth, not only by reducing K27me3 but also through chromosomal missegregation. We aim to elucidate the full extent of EZHIP’s role in epigenetic control, histone post-translational modifications, chromosomal accessibility, and instability. Our findings will provide critical insights into the mechanisms underlying DMG tumorigenesis and potential therapeutic targets.
SURG-26. IMPROVEMENT IN PRECISION AND SURGICAL EFFICIENCY USING THE STEALTH AUTOGUIDE™
Authors: Kaoru Kikuyama, Tomoya Oishi, Tomohiro Yamasaki, Gakuji Maruyama, Hiroaki Neki, Shinichiro Koizumi, Kazuhiko Kurozumi
Journal: Neuro-Oncology (2024)

Abstract INTRODUCTION The Stealth Autoguide™ (Medtronic) automatically determines the path for guiding instruments based on the created surgical plan. It seamlessly integrates continuous real-time navigation with robotic alignment capabilities, enhancing intraoperative workflow efficiency and supporting precise positioning. Our institution has achieved favorable results with surgeries utilizing the Stealth Autoguide™, and we report these outcomes and our future prospects. METHODS We conducted 15 surgeries at our institution using the StealthStation S8 (Medtronic) linked with the Stealth Autoguide™. The average age was 56.2 years, with 10 males and 5 females, all under general anesthesia. RESULTS The cases included 11 gliomas, 2 primary central nervous system lymphomas, 1 germ cell tumor, and 1 brain abscess. Applications of the Stealth Autoguide™ included 7 biopsies (6 burr holes, 1 craniotomy), 6 placements of fenestrations, and 2 tubing placements. The biopsies allowed for quick and reliable tissue sampling. In fenestration cases, it was possible to position quickly and precisely at the target, placing it at the planned site with high accuracy. Additionally, by using a 3D endoscopic system, surgeons could view both the surgical field and navigation screens simultaneously without shifting their gaze, enhancing safety during procedures. In the case of an intraventricular germ cell tumor, tubing preceded by ViewSite™ allowed for a safe and clear surgical field. CONCLUSION Surgeries using the Stealth Autoguide™ were conducted safely and efficiently, regardless of the surgical technique, achieving high-precision positioning. Continuing to utilize this system is expected to improve the accuracy, safety, and reproducibility of surgeries, thereby reducing the burden on patients.
NCMP-19. IMPACT OF SUBVENTRICULAR ZONE INVASION ON PREOPERATIVE COGNITIVE DECLINE IN DIFFUSE GLIOMA PATIENTS
Authors: Ko-Ting Chen, Hsin-Ya Li, Ian-Hou Lao, Yi-Chun Chen, Yah-Yuan Wu, Yi-Chuan Chu, Kuo-Chen Wei, Pin-Yuan Chen, Wei-Han Chang
Journal: Neuro-Oncology (2024)

Abstract PURPOSE To determine the impact of subventricular zone (SVZ) invasion on neurocognitive dysfunction in diffuse glioma patients. MATERIALS AND METHODS We collected neuropsychological assessments of treatment-naïve WHO grade 2-4 diffuse glioma patients between 2017 to 2023. The Chi-square test determined the odds ratio (OR), and multiple linear regression identified factors related to cognitive deficits using Python 3.11.4. RESULTS Of the 129 patients, 64 exhibited SVZ invasion (SVZ+) while 65 were SVZ-. Groups were matched for WHO grading. SVZ+ was associated with more defective domains than SVZ- in both lower grade (WHO grade 2,3, 3.2 ± 2.1 vs. 2.1 ± 1.9, p=0.019) and high grade (WHO grade 4, 4.9 ± 1.6 vs. 3.6 ± 2.2, p=0.019) tumors. In lower grade gliomas, SVZ+ increased risks of language (OR 7.500, p&amp;lt;0.001) and visual learning impairments (OR 4.375, p=0.014). In high grade gliomas, SVZ+ rendered greater language (OR 8.556, p=0.003) and auditory learning vulnerability (OR 3.850, p=0.039). In right hemispheric tumors, SVZ+ lesions conferred worse executive (OR 6.667, p=0.006) and language function (OR 9.063, p=0.017); in left hemispheric tumors, SVZ+ lesions increased language (OR 3.125, p=0.012) and auditory learning (OR 2.889, p=0.024) impairment. Frontal horn of SVZ+ was related to working memory decline, and body part of SVZ+ was related to emotional deficits. Age and WHO grade 4 were associate with more defective domains in the SVZ+ group. In the SVZ- group, parietal lobe tumor was associate with more defective domains, while high education, temporal lobe, and WHO grade 2 were associate with fewer defective domains. CONCLUSION SVZ invasion impacts pre-operative neurocognitive function regardless of lesion laterality and WHO grade. Distinct SVZ sub-regions are linked to specific cognitive impairments. These findings highlight the need for precise tumor mapping involving the SVZ to evaluate neurocognitive outcomes and consider preventive or rehabilitative interventions.
STEM-11. MULTIDIMENSIONAL PROFILING OF TUMOR CELL HETEROGENEITY REVEALS CELL-LINEAGE SPECIFIC FUNCTIONS IN SUPRATENTORIAL EPENDYMOMAS
Authors: Daeun Jeong, Sara G Danielli, Kendra Maaß, David R Ghasemi, Svenja K Tetzlaff, Ekin Reyhan, Carlos Alberto Oliveira de Biagi-Junior, Costanza Lo Cascio, Sina Neyazi, Andrezza Nascimento, Rebecca Haase, Bernhard Englinger, Li Jiang, Cuong M Nguyen, Alicia-Christina Baumgartner, Sophia Castellani, Jacob S Rozowsky, Olivia A Hack, McKenzie L Shaw, Daniela Lotsch-Gojo, Katharina Bruckner, Stefan M Pfister, Marcel Kool, Tomasz Nowakowski, Johannes Gojo, Lissa Baird, Sanda Alexandrescu, Kristian W Pajtler, Varun Venkataramani, Mariella G Filbin
Journal: Neuro-Oncology (2024)

Abstract Supratentorial ependymomas (ST-EPN) are aggressive pediatric brain tumors that are categorized into distinct molecular subgroups. However, the developmental origins, tumor microenvironment, and phenotypic characteristics of tumor subpopulations across these subgroups are still poorly understood. In this study, we explored the human developmental signatures, global spatial organization, and the morphological and migratory tumor cell state behaviors in ST-EPN tumors at unprecedented resolution. We profiled 42 ST-EPN patients encompassing ZFTA-RELA (n = 20), ZFTA-Clusters 1 to 4 (n=20), and ST-YAP1 (n=4) subgroups by single-cell RNA sequencing (scRNA-seq), spatial transcriptomics, and live-cell imaging. We identified recurrent tumor cell states across tumors, that cover both generic cell processes (including cycling and mesenchymal/hypoxia) and human embryonic and fetal brain developmental signatures. ST-EPN subgroups displayed distinct developmental signatures, mapping to two separate temporally restricted progenitors-neuroepithelial-like and embryonic-like cells. Additionally, tumors showed diverging patterns of neuronal or ependymal differentiation, with ZFTA-Cluster 3 tumors as especially distinct from other subgroups in both developmental origin and differentiation. Furthermore, by utilizing 10X Xenium and novel algorithms we discovered that mesenchymal/hypoxia is critical for driving global tissue architecture to become more organized. Notably, recurrent tumors exhibited higher proportion of mesenchymal/hypoxia cells and greater structure than primary tumors. Lastly, by superimposing molecular and functional assays in both in vivo and in vitro models, we found that cell states exhibit distinct morphological and migratory behaviors, with neuronal-like cells being the most invasive. Neuronal-like cells especially exhibited distinct behavioral patterns reminiscent of neuronal migration during development. Moreover, we demonstrated the crucial role of neuronal microenvironment in promoting plasticity of cells toward this neuronal lineage. Taken together, we present a multidimensional framework for investigating cellular states within ST-EPN tumors, offering novel insights into their developmental origins, patterns of spatial organization, and cellular behavioral characteristics.