tbuckley/cabot-search huggingface dataset:
IMMU-69. THERAPEUTIC WINDOW ENABLING ERADICATION OF RESIDUAL GLIOMA STEM CELLS BY INTRACRANIAL NK CELL THERAPY FOLLOWING TEMOZOLOMIDE-INDUCED TUMOUR DEPOPULATION – A POSSIBLE ROLE OF CYTOTOXIC EXTRACELLULAR VESICLES
Authors: Brian Meehan, Lata Adnani, Xianbing Zhu, Nadim Tawil, Delphine Garnier, Ichiro Nakano, Sidong Huang, Janusz Rak
Journal: Neuro-Oncology (2024)

Abstract Glioblastoma (GBM) is an incurable brain cancer, where dismal outcomes result from disease recurrence driven by tumour-initiating glioma stem cells (GSCs). GSCs survive and expand in the brain after surgery, radiation and temozolomide (TMZ) amidst weak immune and natural killer (NK) cell surveillance. Efficient NK cell-mediated killing of GBM cells occurs at high effector to target ratios precluding effective eradication of large tumour remnants, as enforced by clinical trials with autologous NK cells in an adjuvant setting. Here we explore in a human GSC xenograft model whether tumor depopulation using high dose Temozolomide (TMZ) could create a window of curative opportunity for endogenous or exogenous NK cells. We observed that while subcutaneous (sc) xenografts of patient derived GSCs are infiltrated by endogenous functional (NCR1+) NK cells in SCID mice, the corresponding intracranial (ic) tumours remained NK cell depleted. Notably, while TMZ caused near complete regression of intracranial GSC xenografts this was followed by inevitable recurrence of drug-resistant lesions. To explore whether direct delivery of NK cells into depopulated intracranial tumours would change the lethal course of the disease, mice were injected with GSCs intracranially, and upon tumour formation were treated with a sequence of TMZ (systemically), at 2, 7, 14, and 21 days later with irradiated NK92MI cells. Remarkably, this combined therapy completely obliterated recurrent disease at 2 and 7 days but not beyond 14 days. To assess whether NK92MI cells could be replaced by their derived extracellular vesicles (NK-EVs), the latter were injected i.c. post TMZ in GSC xenograft bearing mice. A single injection of NK-EVs resulted in tumour eradication in some but not all mice. Thus, chemotherapy-dependent tumour depopulation may create a unique window of opportunity for curative NK-mediated immunotherapy in GBM.
RADT-50. CLINICAL OUTCOME OF DAILY 5-FRACTIONATED GAMMA KNIFE RADIOSURGERY FOR LARGE BRAIN METASTASES
Authors: Juhee Jun, Young-Hoon Kim
Journal: Neuro-Oncology (2024)

Abstract INTRODUCTION With the introduction of the Gamma Knife Icon, hypo-fractionated Gamma Knife radiosurgery (GKRS) for large brain metastases (LBMs) is beginning to be performed. This study aimed to assess the clinical outcome and risk of the daily 5-fractionated GKRS for LBMs. METHODS A total of 100 patients who underwent 5-fractionated GKRS for LBMs (&amp;gt; 14cm3) were enrolled. Forty-six were male patients, and the median age was 60 years. Most common primary cancer sites were lung (41 non-small cell cancers), breast (24), and kidney (14). The median tumor volume was 22cm3 (14 – 69cm3) and marginal dose was 35Gy (50% isodose line) in 5 fractions. Median follow-up duration was 18 months (3 – 72 months). RESULTS The last follow-up showed local tumor control in 74 cases. The cumulative 1, 2, and 3-year local tumor control rates were 73, 65, and 60%, respectively. Eighty-six tumors showed best MRI response in a year, and median tumor volume decrease rate was 80% (22 – 100%). Thirty patients experienced dramatically tumor volume decrease (&amp;gt; 95%). Median progression free and overall survival were 7 and 16 months, respectively. Radiation necrosis occurred in 24 patients, of which only 9 had neurological symptoms and treated with steroid and bevacizumab. CONCLUSIONS The daily 5-fractionated GKRS for very LBMs showed favorable local tumor control and acceptable radiation necrosis, but questionable survival benefit. In the future, prospective multi-center study is needed.
EXTH-54. COMBINATORIAL DRUG SCREENING IDENTIFIES CARFILZOMIB AND ENZALUTAMIDE FOR TREATING AGGRESSIVE MENINGIOMAS
Authors: Gerhard Jungwirth, Viktor Braun, Derin Nalcakan, Yimin Pan, Rolf Warta, Amir Abdollahi, Andreas Unterberg, Sandro Krieg, Christel Herold-Mende
Journal: Neuro-Oncology (2024)

Abstract The goal of combinatorial therapy is to improve the effectiveness of treatment by targeting multiple aspects of cancer cells or overcoming resistance to single drugs. Therefore, we performed an automated combinatorial drug screening in meningioma cell lines and patient-derived tumor organoids (TOs). Three grade 3 meningioma cell lines (NCH93, IOMM-Lee, and KT21-MG1) were stably transduced with blue, green, and red fluorescence proteins. The cell lines were multiplexed into 384-well plates and treated in 5x5 dose-response (0-1000 nmol/l) matrices for 48h by the automated liquid handler Hamilton MicroLAB STAR®. The drug library consisted of 166 FDA-approved anticancer drugs. The viability of each cell line was demultiplexed by using fluorescence signals and CellTiterGlo. TOs were established from single cell suspensions of freshly resected meningioma tissue (n=20). The ZIP model was used to determine synergism. This drug screening effort generated 13,695 unique drug-drug combinations per cell line. Most synergistic combinations were observed in IOMM-Lee (1.14%), followed by KT21-MG1 (0.88%), and NCH93 (0.54%). The 110 most effective drug combinations were validated in wild-type meningioma cells. 75 drug combinations demonstrated a positive most synergistic area (MSA) score, indicating synergistic effects. Based on synergy scores and literature evidence, the 16 most promising combinations were selected for screening in TOs. The proteasome inhibitor carfilzomib in combination with the androgen receptor inhibitor enzalutamide exhibited the highest synergy in TOs. In 40% (n=8/20) of the cases, the combination showed strong synergism (MSA&amp;gt;10) resulting in an overall average MSA of 7.36, followed by carfilzomib and neratinib, and romidepsin and gemcitabine with average MSAs of 5.49, and 4.32, respectively. Furthermore, carfilzomib and enzalutamide induced apoptosis in TOs assessed by Caspase-3/7. This comprehensive combinatorial drug screening identified the synergistic combination of the proteasome inhibitor carfilzomib and androgen receptor inhibitor enzalutamide that can be an effective treatment option for selected meningioma patients.
SURG-57. FLUORESCENCE LIFETIME IMAGING (FLIM) PROVIDES HIGHLY ACCURATE, DYE-FREE TUMOR MARGIN DETECTION DURING GLIOMA RESECTIONS
Authors: Orin Bloch, Silvia Anbunesan, Alba Alfonso-Garcia, Han Lee, Robert Riestenberg, Laura Marcu
Journal: Neuro-Oncology (2024)

Abstract INTRODUCTION Fluorescence guided tumor margin detection is an important tool to enhance the extent of resection for gliomas. Existing dyes, such as 5-ALA, require planned administration, surgical resection in dark conditions, and are only effective for high-grade tumors. We have developed a novel laser scanning probe to assess tissue autofluorescence decay (lifetime) which allows tumor margin detection without exogenous dyes and under normal room light conditions. This technology has been optimized for margin detection in low-grade and high-grade gliomas. METHODS Patients undergoing craniotomy for resection of gliomas were enrolled. During resection of the final tumor margin, multiple 1x1 mm regions were scanned with FLIm and biopsied for evaluation by a neuropathologist. FLIm data and ground truth pathology were processed by a machine-learning algorithm to develop classifiers for the FLIm data. Classifiers were then applied to the full data set to determine the accuracy of FLIm predictions. RESULTS 12 patients with non-enhancing (LGG) and 25 patients with enhancing (HGG) tumors were enrolled, with a total of 228 biopsies obtained. For LGG, sensitivity of FLIm for detection of residual tumor was 0.89 (95% CI 0.8-0.98) with a specificity of 0.92 (95% CI 0.86-0.97), resulting in a positive predictive value of 0.76 and negative predictive value of 0.96 with an overall accuracy of 0.91. For HGG, sensitivity of FLIm for detection of residual tumor was 0.92 (95% CI 0.84-1.0) with a specificity of 0.95 (95% CI 0.91-0.99), resulting in a positive predictive value of 0.90 and negative predictive value of 0.96 with an overall accuracy of 0.94, exceeding reported values for 5-ALA. CONCLUSION FLIm can distinguish between residual low and high-grade glioma and normal brain at resection margins with very high sensitivity and specificity. This quantitative technology does not require administration of exogenous dyes and can be used under normal room light illumination.
PATH-22. SINGLE-CELL RNA (SCRNA) SEQUENCING OF PAIRED PRIMARY AND RECURRENT ATYPICAL TERATOID/RHABDOID TUMORS (AT/RT) REVEALED MOLECULAR DIFFERENCES AND THERAPY-RESISTANT PRIMARY TUMOR CELLS
Authors: Lea Altendorf, Rajanya Roy, Flavia W de Faria, Karoline Hack, Arend Koch, Martin U Schuhmann, Peter Hauser, Pascal D Johann, Martin Hasselblatt, Kornelius Kerl, Michael C Frühwald, Ulrich Schüller
Journal: Neuro-Oncology (2024)

Abstract Atypical teratoid/rhabdoid tumors (AT/RT) are the most common malignant brain tumors during infancy. They split into four molecular types. The major three (AT/RT-SHH, AT/RT-TYR, and AT/RT-MYC) all carry mutations in SMARCB1, the fourth smaller type is characterized by SMARCA4 mutations (AT/RT-SMARCA4). AT/RT are associated with a dismal outcome, and 50% of the patients suffer a progress or recurrence of the tumor. Molecular mechanisms of disease recurrence are currently unclear. Here, we identified molecular characteristics of AT/RT primaries and recurrences, which could help to improve the therapy for relapsed patients. Previously, we investigated tumor tissue from 26 patients revealing signatures of recurrences in comparison to matched primary tumor samples using histology, DNA methylation analysis, and bulk RNA sequencing. To further identify mechanisms regarding tumor progression and recurrence, we performed single-cell RNA (scRNA) sequencing for five of these primary-recurrence pairs so far using formalin-fixed paraffin-embedded (FFPE) tissue. Using Uniform Manifold Approximation and Projection (UMAP) for dimensionality reduction, we observed a distinct separation in the gene expression profiles of primary and recurrent tumor cells. In addition, we aimed to identify primary tumor cells which potentially persisted after therapy and developed to recurrences. Therefore, we identified primary tumor cells showing highest similarity to recurrent tumor cells using CIBERSORT and trajectory analysis. Differentially expressed genes of these specific primary tumor cells were investigated. They are involved in cell migration, -adhesion, -proliferation, and -stability, among others. Overall, molecular characteristics that occur in the course of the disease were identified, which may help to define new therapeutic targets for AT/RT recurrences.
STEM-10. NEURAL PROGENITOR CELL MARKERS IN IDH MUTANT AND IDHWT GLIOMAS
Authors: Iyad Alnahhas, Allison Kayne, Mehak Khan, Wenyin Shi
Journal: Neuro-Oncology (2024)

Abstract INTRODUCTION Single-cell RNA sequencing (scRNA-seq) has helped to elucidate the cellular composition of cancer and its microenvironment. Recent scRNA-seq studies have highlighted the heterogeneity of glioblastoma (GBM). Moreover, single-cell GBM analyses have proposed resemblance of GBM cells to radial glia and outer radial glia, supporting the hypothesis that remnants of developmental tissue get reactivated in cancer. A recent study isolated neural progenitor cells (NPCs) from developing fetal human brain (gestational week 17–19) and classified NPCs based on their expression of THY1, CD24 and EGFR. Ventricular radial glia are THY1- CD24-EGFR+ whereas outer radial glia are THY1- CD24-EGFR-. Early neuron precursors are CD24+THY1-EGFR+ and glial progenitor cells (GPCs) are THY1+EGFR+. GPCs give rise to THY1+EGFR+PDGFRA+ pre-oligodendrocyte progenitor cells. The importance of EGFR in NPCs again highlights the resemblance to glioma. METHODS We aimed to apply the classification above to IDH mutant astrocytoma and oligodendroglioma as well as IDHwt glioblastoma samples. We used three publicly available datasets: Wang (paired 74 IDHwt primary and recurrent samples), Tirosh (6 primary oligodendroglioma samples) and Venteicher (10 primary IDH mutant astrocytoma). RESULTS In IDH mutant astrocytoma, 82.63% of cells express THY1+ (mostly EGFR+PDGFRA+) and 10.76% of cells are THY1-CD24-EGFR+. In oligodendroglioma, 75% of cells are THY1+ (mostly EGFR+PDGFRA+) and 12.07% are THY1-CD24-EGFR+. In IDHwt EGFR amplified primary GBM samples, 87.5% of cells are THY1-CD24-EGFR+. This percentage drops to 70.4% in the recurrent setting. THY1-CD24-EGFR- cells increase from 9.7% to 23.1% at recurrence. In IDHwt EGFRwt primary GBM samples, 48.6% of cells are THY1-CD24-EGFR+ and 44.15% are THY1-CD24-EGFR-. In the recurrent setting, 43.26% of cells are THY1-CD24-EGFR+ and 49.58% are THY1-CD24-EGFR-. CONCLUSION IDH mutant gliomas and IDHwt glioblastoma express different progenitor cell markers and may have a different cell of origin. THY1 is highly expressed in IDH mutant gliomas.
SURG-19. THE SYNDROME OF THE SUPPLEMENTARY MOTOR AREA: CLINICAL COURSE AND PREDICTORS OF OUTCOME AFTER RESECTION OF PREMOTOR LESIONS
Authors: Nico Teske, Leonard B Jung, Jan O Nöldeke, Thomas Weig, Jens Blobner, Robert Forbrig, Joerg-Christian Tonn, Mathias Kunz, Niklas Thon, Philipp Karschnia
Journal: Neuro-Oncology (2024)

Abstract OBJECTIVE Supplementary motor area (SMA) syndrome frequently occurs after resection of premotor lesions. Interhemispheric connectivity including the contralateral SMA might be crucially involved in its development and recovery. We aimed to identify predictors of outcome by quantifying preoperative structural alterations in the non-affected contralateral hemisphere. METHODS We retrospectively searched our database for patients developing SMA syndrome after resection of premotor lesions between 2013 and 2023. Clinical characteristics and imaging data were collected. Structural network analysis was performed using the previously validated morphometric inverse divergence network. RESULTS 27 patients with a mean age of 39.2 ± 17.7 years developed SMA syndrome, including 13/27 patients (48.1%) with primary brain tumors and 14/27 patients (51.9%) with intractable lesional epilepsy. Postoperative SMA syndrome was commonly characterized by contralateral upper extremity hemiparesis (19/27 patients, 70.4%) and aphasia in case of dominant hemisphere involvement (13/13 patients, 100%). Tumor patients were less likely to fully recover from SMA syndrome after 7 days compared to epilepsy patients (2/13 [15.4%] versus 9/14 [64.3%] patients, p=0.018). Most patients (23/27, 85.2%) experienced full recovery of SMA syndrome after a median follow-up of 5 months (IR 3-16 months), with no difference between patients with tumors or epilepsy (p=0.999). Preoperative contralateral intra-hemispheric connectivity was similar between patients receiving tumor or focal resection (0.183 vs 0.177, p=0.295). However, imaging analyses demonstrated baseline affection of SMA connectivity in patients with brain tumors as characterized by reduced cortical thickness of the contralateral frontal lobe and the cingulate gyrus compared to epilepsy patients. CONCLUSION While full recovery from SMA syndrome is common, SMA syndrome is frequently less severe and more transient in patients with epilepsy. This might be due to affection of the contralateral SMA network in tumor patients due to the infiltrative nature of the disease. Imaging analyses might assist in identifying network affections at baseline.
TMIC-35. MITOCHONDRIAL TRANSFER PROMOTES ASTROCYTE REACTIVITY IN GLIOBLASTOMA
Authors: Jonathan Mitchell, Defne Bayik, Dionysios Watson
Journal: Neuro-Oncology (2024)

Abstract Astrocytes are the most abundant glial cell in the brain and have been shown to adopt reactive phenotypes upon interaction with glioma cells. While tumor-associated astrocyte (TAA) reactivity is linked to increased inflammation, proliferation, invasion, and treatment resistance of glioblastoma (GBM), the mechanisms by which cancer cells reprogram TAA are poorly defined. We have previously shown that mitochondrial transfer from astrocytes to GBM cells via GAP43-dependent microtubes alters GBM cellular metabolism and increases tumorigenicity. However, the potential role of this communication mechanism in TAA function remains unknown. Patient-derived GBM cells (PDCs) were transduced with a mito-GFP lentiviral vector and were co-cultured with hTERT-immortalized, mito-mCherry human astrocytes. Using flow cytometry, we observed that the frequency of mitochondrial transfer to hTERT astrocytes was dependent on GBM cell type and noted transfer rates as high as ~40% in co-cultures with L1 PDCs. Utilizing high-resolution confocal microscopy, we subsequently confirmed co-localization of fluorescent protein signal with MitoTracker Deep Red and observed increases in mitochondrial biomass in transfer-positive astrocytes. To evaluate whether mitochondrial transfer occurs in the tumor microenvironment, we implanted immunocompromised mice with L1 mito-mCherry PDCs. Approximately 17.7% of mouse TAAs in the tumor core were positive for GBM mitochondria, whereas long-distance transfer was not observed in the contralateral hemisphere. Functionally, acquisition of tumor mitochondria promoted astrocyte proliferation as measured by cells in G2/M phase and significantly increased total cellular reactive oxygen species (ROS) levels. These findings highlight a process by which astrocytes may become reactive in response to increased ROS from GBM mitochondrial transfer. Future studies will investigate the cellular response to increased ROS in astrocytes and investigate potential links to inflammatory and immunosuppressive signaling. Elucidating how GBM-to-astrocyte mitochondrial transfer reprograms TAA would help identify therapeutic vulnerabilities that can be exploited by blocking mitochondrial transfer.
SURG-27. DIRECTIONALLY NON-ROTATING ELECTRIC FIELD THERAPY (DNEFT) DELIVERED THROUGH IMPLANTED ELECTRODES: A NOVEL SURGICAL PLATFORM FOR GLIOBLASTOMA IMMUNOTHERAPY
Authors: Jun Ma, Shilpi Singh, Ming Li, David Seelig, Gregory Molnar, Eric Wong, Sanjay Dhawan, Stefan Kim, Logan Helland, David Chen, Nikos Tapinos, Sean Lawler, Gatikrushna Singh, Clark Chen
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND While directionally rotating Tumor Treating Fields (TTF) therapy has garnered considerable clinical interest in recent years, there has been comparatively less focus on directionally non-rotating electric field therapy (dnEFT). OBJECTIVE Here, we explore dnEFT generated through implanted electrodes as a glioblastoma therapeutic platform, with the goal of facilitating clinical translation. METHODS Using custom-designed electrode arrays to study the effect of dnEFT using in vitro and in vivo glioblastoma models. RESULTS In vitro, dnEFT generated using a clinical grade spinal cord stimulator showed anti-neoplastic activity against independent glioblastoma cell lines. In support of the results obtained using the clinical grade electrode, dnEFT delivered through a customized, two-electrode array induced glioblastoma apoptosis. To characterize this effect in vivo, a custom-designed four-electrode array was fabricated such that tumor cells can be implanted into murine cerebrum through a center channel equidistant from the electrodes. After implantation with this array and luciferase expressing murine GL261 glioblastoma cells, mice were randomized to dnEFT or placebo. Relative to placebo treated mice, dnEFT reduced tumor growth (measured by bioluminescence) and prolonged survival (median survival gain of 6.5 days). Analysis of brain sections following dnEFT showed a notable increase in the accumulation of peri-tumoral macrophage/microglia with increased expression of M1 genes (IFNγ, TNFα, IL-6) and decreased expression of M2 genes (CD206, Arg, IL-10) relative to placebo tumors. CONCLUSIONS Our results suggest therapeutic potential in glioblastoma for dnEFT delivered through implanted electrodes as a novel immunotherapy platform, supporting the concept of a proof-of-principle clinical trial using commercially available deep brain stimulator electrodes.
TMIC-54. OHSV-MEDIATED NOTCH BLOCKADE FOR BRAIN TUMORS
Authors: Kimberly Rivera Caraballo, Bangxing Hong, Tae Jin Lee, Karina Vázquez-Arreguín, Sara Murphy, Ashok Sharma, Balveen Kaur
Journal: Neuro-Oncology (2024)

Abstract Primary brain tumors such as glioblastoma (GBM) are refractory to current standard-of-care, and so there is an urgent need to develop novel therapies to treat brain tumors. NOTCH is a cell-cell communication pathway that is exploited by GBM stem cells to bypass treatment. The role of NOTCH signaling in tumor growth and resistance is well studied, but the significance of this pathway for immunotherapy of GBM is not very well understood. We have recently shown that NOTCH activation with viro-immunotherapy contributes to tumor regrowth and induces recruitment of monocytic MDSC cells into the tumor, which limit optimal immune activation to kill tumor cells. Herein, we evaluated the impact of blocking NOTCH signaling using two different peptides: NIX1 and NIX2 that can interfere with NOTCH ligand binding with their receptors. Both NIX1 and NIX2 could effectively block the ligation of NOTCH ligands with Notch receptors in the tumor microenvironment. Secretion of both NIX1 and NIX2 was confirmed by western blot (WB) and ELISA. Functionality of NIX1 and NIX2 to block NOTCH signaling was assessed by western blot analysis for NOTCH cleaved intracellular domain (NICD). RNA sequencing and PCR based assays were utilized to evaluate the impact of NIX1 and NIX2 on global pathways that were enriched. Gene therapy using oncolytic immunotherapy vectors revealed that both NIX1 and NIX2 could suppress NOTCH signaling. In vitro, NIX1 and NIX2 did not increase the benefit of viro-immunotherapy. Treatment of mice bearing intracranial tumors with NIX1 or NIX2 armed viro-immunotherapy revealed a significant increase in therapeutic benefit with some long-term survivors. Both NIX1 and NIX2-expressing viruses induced macrophage migration relative to unarmed viro-immunotherapy in two different glioma models. Role of macrophages in guiding therapeutic benefit is currently being explored.