tbuckley/cabot-search huggingface dataset:
TMIC-20. UNLOCKING THE POTENTIAL OF HYPOXIA REDUCTION IN RESHAPING THE GLIOBLASTOMA TUMOR MICROENVIRONMENT FOR ENHANCED THERAPEUTIC SYNERGY
Authors: Ivana William, Kristin Huntoon, Spencer Lea, Krithikaa Rajkumar Bhanu, Shweta Hegde, Betty Kim, Michael Curran
Journal: Neuro-Oncology (2024)

Abstract Glioblastoma (GBM) tumors respond poorly to nearly all cancer therapies due to their highly immunosuppressive tumor microenvironment (TME). Hypoxia exacerbates this immunosuppression by upregulating the hypoxia-inducible factor (HIF) pathway in glioma-associated myeloid cells (GAMs) which suppressively polarizes them to maintain this immune “cold” state. This hypoxia-driven programming inhibits CD8+ T cell infiltration and effector function by inducing metabolic dysfunction, thereby increasing resistance to chemotherapy and T cell immune checkpoint blockade (ICB). Targeting hypoxia thus emerges as a promising strategy to overcome such resistance. Our study suggests that GBM hypoxia ablation can convert the immunosuppressive tumor microenvironment into a more pro-inflammatory one. Tumor hypoxia ablation using the hypoxia-activated prodrug Evofosfamide significantly enhances survival in both GL261 (p&amp;lt;0.0001) and the checkpoint blockade-resistant CT2A murine GBM models (p&amp;lt;0.01). Evofosfamide treatment boosts tumor infiltrating Ki67+ proliferative CD8+ T cells (p&amp;lt;0.001) and heightens cytotoxicity, indicated by increased Granzyme B expression (p&amp;lt;0.01). It also reduces the co-expression of exhaustion markers LAG-3 and TIM-3 (p&amp;lt;0.001), signaling decreased T cell exhaustion. Antigen-specific CD8+ T cells from Evofosfamide-treated primary GBM tumors exhibit enhanced ex vivo killing capacity when co-cultured with GL261-OVA cells (p&amp;lt;0.001). Furthermore, Evofosfamide enhances microglia proliferation and repolarizes them towards a pro-inflammatory state, marked by upregulation of M1 markers such as CD80 (p&amp;lt;0.001) and downregulation of M2 markers like Arginase (p&amp;lt;0.05). Hypoxia reduction also increases chemotherapy sensitivity, synergistically improving survival when combined with the blood-brain barrier-penetrating, immunogenic chemotherapy Berubicin (CT2A; vehicle MS=26d, Evo MS=36d, Berubicin MS=55d, Combo MS=70.5d). Future research will investigate the mechanisms underlying this shift towards a pro-inflammatory state, focusing on metabolic changes in CD8+ T cells and the impact of altered HIF pathway signaling on GAM polarization following hypoxia ablation. Understanding the therapeutic potential of reversing hypoxia-mediated immunosuppression could lead to novel combination therapies capable of overcoming resistance to both chemotherapy and immunotherapy in GBM.
IMMU-59. AN IMMUNOSUPPRESSIVE PROGRAM ENCOMPASSING MULTIPLE IMMUNE CELL TYPES IN GBM TYPIFIED BY NOVEL MARKER LRRC25 ASSOCIATED WITH TYROBP SIGNALING
Authors: Daniel Zamler, Radhika Mathur, Gary Chan, Patrick Schupp, Anny Shai, Hideho Okada, Michael Oldham, Joseph Costello
Journal: Neuro-Oncology (2024)

Abstract Immunosuppression in glioblastoma is a powerful impediment to effective immunotherapy. We used maximal tumor sampling and genome-wide coexpression analysis of RNA sequencing, on 69 samples from 8 patients, to identify a module of 270 genes marked by LRRC25, determined by top fidelity score, that covaries with many immunosuppressive molecules. An immunosuppressive module was independently derived from an expanded cohort of 319 samples from 28 GBM also marked by LRRC25 by top fidelity score. Within the gene module, we observed strong co-variation of markers for monocytes, neutrophils, and NK cells with LRRC25. In published single-cell RNA-seq from glioma, we determined that LRRC25 is expressed by neutrophils and myeloid cells while absent from NK-cells. LRRC25 is also constitutively expressed in monocytes and neutrophils while being upregulated by microglia and DCs in the tumor core and necrotic regions. In addition to covariation with multiple cell-type specific markers we also discovered that LRRC25 expression is tightly associated with several members of the TYROBP causal signaling network in microglia. Thus, LRRC25 may play a novel role in TYROBP signaling which may, in turn, represent a novel mechanism of NK cell and neutrophil immunosuppression in glioma. We confirmed LRRC25 RNA expression in patient samples by RNAscope co-stained with an anti-CD163 antibody indicating myeloid expression, as well as tumor cell expression determined by histopathology. Although LRRC25 is known to mediate IFN and NFKb signaling in myeloid cells in-vitro, its function in glioma remains understudied. While significant efforts have focused on mechanisms of myeloid to T-cell immunosuppression, less focus has been given to mechanisms of myeloid to NK-cell and neutrophil immunosuppression, despite the fact they exist at levels comparable to T-cells in the tumor microenvironment. This work will be followed up with antibody validation as well as genetic manipulation of LRRC25 in-vitro and in-vivo.
QLTI-02. THE ROLE OF REOPERATION IN PAEDIATRIC PILOCYTIC ASTROCYTOMA
Authors: Michelle Kameda, Katherine Green, Dana Hutton, Noor ul Owase Jeelani, Dominic Thompson, Darren Hargrave, Kristian Aquilina
Journal: Neuro-Oncology (2024)

Abstract INTRO Cerebellar pilocytic astrocytomas (cPAs) in childhood have long been recognized to have a good prognosis after total resection, but the outcome after incomplete resective surgery remains largely unpredictable, with the incidence of radiological progressive disease ranging from 18-100%. It has been traditionally thought that gross-total resection was required for long-term survival, and small residuals were classically resected in a subsequent operation. OBJECTIVE To determine the role of reoperation in residual or recurrent cerebellar pilocytic astrocytoma. METHODS The authors analyzed their pediatric low-grade clioma (PLGG) database for cases treated between 1985-2020 and filtered for intracranial PAs, to determine what clinical or radiological factors precipitated revisional resective surgery in their single quaternary care center cohort. RESULTS Using the PLGG database, 283 patients &amp;lt;18 years of age were identified to have a histopathological diagnosis or intracranial PA between 1985-2020, of which, 200 were within the cerebellum (70.7%). The majority of patients with cPA were between 1 and 10 years of age (n=145, 72.5%) without gender preponderance (M/F=99:101) usually presenting with 1 lesion (n=197, 98.5%). Gross total resection was achieved in 74.5% (n=149) of initial surgeries for cPA. In patients with subtotal resection, the mean largest diameter of the postoperative residual tumor was 1.06cm (range 0-2.95cm). Seven patients with subtotal resection did not require a second resective intervention. In 31 patients the neuro-oncology multi-disciplinary team recommended a second resection at a mean time interval of 22.9 months (range 0.13-81.6 months) from the initial surgery. Proportionally, the children who underwent multiple resections were also more likely to receive adjuvant chemo/radiotherapy. Functionally, the children in the multiple operation cohort experienced more complications of therapy including ongoing endocrinopathy, treatment-associated hearing deficit, and neuro-cognitive deficits. CONCLUSION Residual disease in cPA should be maintained under clinico-radiological surveillance postoperatively with adoption of a more conservative approach when residual disease is not significantly changing over time.
BIOM-41. HMGB2 IS A CANDIDATE PROGNOSTIC BIOMARKER IN BOTH ADULT AND PEDIATRIC DIFFUSE GLIOMAS
Authors: Aline Becker, Valesio Becker, Zaid Sirhan, Joseph McElroy, S Jaharul Haque, Arnab Chakravarti
Journal: Neuro-Oncology (2024)

Abstract Few prognostic molecular markers are common to pediatric- and adult diffuse gliomas (PDG and ADG). HMGB2 is a protein expressed in human brain development and in de-differentiated high-grade gliomas (HGG), which we have recently described as a putative prognostic and predictive biomarker in ADG, associated with proliferative activity and EIF2 signaling pathway upregulation. Additionally, we showed that HMGB2 shRNA knockdown (HMGB2-KD) reduced cell proliferation and colony formation, and radio-sensitized ADG cell lines. Aims: To assess the prognostic potential of HMGB2 in PDG and its association with stemness. METHODS 1) We singled out HMGB2 from proteomic profiles of an independent PDG cohort previously associated with EIF2 and MYCN signaling upregulation for survival analysis. 2) PDG cells SF188 were de-differentiated with substitution of DMEM by a neurobasal (NB) medium devoid of serum for stemness association studies. 3) We generated HMGB2-KD clones of PDG cell lines SF188 (grown in DMEM and NB) and KNS42 with 3 different shRNAs. RESULTS HMGB2 expression was significantly related to histological grade in PDG (grade 3 vs. grade 2 and grade 4 vs. grade 2: fold change= 8.16 and 9.39; p=0.0045 and &amp;lt;0.001; FDR= 0.04 and 0.0006, respectively) and survival (p=0.004, FDR=0.142 for PFS and p=0.03, FDR=0.291 for OS), in a Cox model including age and grade as covariables. Compared with cells growing in DMEM, SF188 cells growing in NB medium had a morphological change from stellate cells to round cells growing in spheres, with 2-fold increase in C-MYC and HMGB2 expression by Western analysis. HMGB2-KD resulted in &amp;gt;90% reduction of HMGB2 expression in SF188 and &amp;gt;70% in KNS42. CONCLUSION Collectively, our preliminary results suggest that HMGB2 is associated with stemness, has similar roles in PDG and ADG, and may be validated as prognostic/predictive biomarker in both adult and pediatric populations. Mechanistic studies of radiation response are underway.
SURG-44. TO PROCEED OR NOT TO PROCEED: THE IMPACT OF FROZEN SECTION PATHOLOGY ON INTRAOPERATIVE BRAIN BRACHYTHERAPY IMPLANTATION FOR RECURRENT GLIOBLASTOMA
Authors: Sabrina Zeller, Sauson Soldozy, Eris Spirollari, Divya Rao, John Floyd, James Zhu, Simon Hanft
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Glioblastoma (GBM) is a highly aggressive malignancy that recurs in up to 90% of patients following standard-of-care therapy, including surgical resection, concurrent chemoradiotherapy, and subsequent adjuvant chemotherapy. In cases of prior radiation therapy (RT) use, one option for localized, recurrent GBM (RGBM) is STaRT (Surgically Targeted Radiation Therapy) (GammaTile, GT Medical Technologies, Tempe AZ USA), a form of brachytherapy utilizing cesium-131 seeds implanted at the time of re-resection. One of the potential concerns with STaRT implantation for RGBM is that intraoperative frozen section pathology may demonstrate only necrosis, in which case further RT may not be advisable. This concern is often cited as a deterrent to offering an intraoperative brachytherapy treatment in RGBM cases. Herein we review the frequency of intraoperative frozen section diagnosis returning radiation necrosis leading to aborted GammaTile placement. METHODS The GammaTile Registry, a prospectively enrolling multi-center phase 4 study (NCT04427384), was assessed for all patients receiving intraoperative brachytherapy for RGBM from 10/2020 to 3/2024. Data regarding patient demographics, procedure details, and pathology were extracted and analyzed. RESULTS A total of 122 RGBM patients with a median age of 59 years (range 28-86) were scheduled for STaRT. Of these, 109 (89.3%) patients had confirmed prior radiation with a median RT dose of 60.0Gy (range 16-75). Only two (1.6%) planned cases of GammaTile placement were aborted after intraoperative frozen section pathology demonstrated extensive radiation necrosis without viable tumor. The patients had received fractionated RT to 55.8Gy and 60.0Gy, respectively. While both frozen samples were predominantly necrosis, the final pathology demonstrated foci of residual glioblastoma in both cases. CONCLUSIONS While it is uncommon in RGBM to abort STaRT due to intraoperative pathology indicating only radiation necrosis, careful consideration should be given when aborting the procedure as in this series final pathology ultimately demonstrated viable tumor cells.
TMET-29. TARGETING IDH1-MUTATED OLIGODENDROGLIOMA WITH ACID CERAMIDASE INHIBITORS
Authors: Helena Muley Vilamu, Tyrone Dowdy, Faris Zaibaq, Mioara Larion
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Currently, an estimated 14,950 people lives with oligodendroglioma in the United States. Oligodendroglioma is genetically defined as a tumor harboring isocitrate dehydrogenase 1 or 2 mutations (IDH1mut/IDH2mut). Previously, we reported that in IDH1mut gliomas, D-2HG, the product of IDH1 mutant enzyme produces an increase in monounsaturated fatty acid levels that are incorporated into ceramides, tilting the S1P-to-ceramide rheostat toward apoptosis. Herein, we exploited this imbalance to further induce and IDHmut-specific glioma cell death. METHODS TCGA and CCGA data were used to explore the association between acid ceramidase (AC) gene expression and patient survival. CCK8 viability assays were carried out to measure the sensitivity of glioma cell lines to acid ceramidase inhibitors. Western blot and liquid chromatography-mass spectrometry analyses were performed for studying the mechanism of action of acid ceramidase inhibitors. The in vivo efficacy of the SABRAC drug, an irreversible inhibitor of AC, was evaluated in an orthotopic oligodendroglioma xenograft mice model using TS603 patient-derived oligodendroglioma cells. RESULTS. We report for the first time that the inhibition of acid ceramidase (AC) induces apoptosis and increases the survival of mice with IDH1mut oligodendroglioma. We demonstrated an IDH1mut-specific cytotoxicity of SABRAC, in patient-derived oligodendroglioma cells. Exploring the mechanism of action of this drug, we found that SABRAC activates both extrinsic and intrinsic apoptosis in an ER stress-independent manner, pointing to a direct action of AC-related ceramides in mitochondria permeability. The activation of apoptosis detected under SABRAC treatment was associated with up to a 30-fold increase in some ceramide levels and its derivatives from the salvage pathway. CONCLUSIONS We propose AC as a novel therapeutic target in oligodendroglioma with IDH1mut and we are conducting additional preclinical testing.
STEM-19. TARGETING<i>GIHCG</i> LNCRNA IN GLIOBLASTOMA STEM CELLS: A POTENTIAL THERAPEUTIC STRATEGY
Authors: Rasmani Hazra
Journal: Neuro-Oncology (2024)

Abstract Glioblastoma multiforme (GBM) remains the most lethal and prevalent primary brain tumor worldwide. Despite advances in understanding its biology and multimodal therapy options, the overall prognosis for GBM patients remains bleak, primarily due to the high recurrence rate, which is intimately linked to tumor resistance against standard therapeutic interventions. Glioblastoma stem cells (GSCs) contribute to therapeutic resistance and cellular heterogeneity through their self-renewal properties and ability to adapt. Thus, identifying new molecular targets driving GBM progression is crucial for developing effective therapies. Recent advancements in genome biology have revealed that long non-coding RNAs (lncRNAs) play roles in various biological functions, and the dysregulation of numerous lncRNAs has been shown to be associated with specific cancers. To identify GSC-associated lncRNAs, a comprehensive analysis was performed using single-cell RNA sequencing datasets from GBM tumors, GBM organoids, GSC-enriched GBM tumors, as well as normal human brain samples. A chromatin-enriched lncRNA, GIHCG, was identified as being highly expressed in GSCs compared to non-neoplastic neural stem cells. The GIHCG gene, located on human chromosome 12q14.1, is frequently amplified in glioblastoma and impacts overall survival. Bioinformatic and functional analyses revealed that GIHCG is amplified in 13% of GBM patient samples, and high expression of GIHCG is a negative prognostic marker for GBM patients, with significantly reduced overall survival compared to the low expression group. In addition, the depletion of GIHCG significantly reduced GSC proliferation and migration. Further, the knockdown of GIHCG decreased both mRNA and protein expression levels of critical GSC stemness factors, including SOX2, NESTIN, and OLIG2. Moreover, GIHCG depletion reduced the sphere formation capacity of GSCs, demonstrating the functional importance of GIHCG in the maintenance of GSC stemness. These results indicate that GIHCG is essential for GSC proliferation, migration, and stemness, underscoring its potential therapeutic value in RNA-based therapies for combating glioblastoma malignancy.
IMMU-11. GUARDIANS OF INNATE IMMUNE ACTIVATION: CRUCIAL ROLES OF NONO AND CGAMP IN GLIOMA VIROTHERAPY
Authors: Andrew Gillard, Dong Ho Shin, Virginia Laspidea, Sanjay Singh, Hong Jiang, Fan Xuejun, Andres Lopez-Rivas, Akhila Parthasarathy, Jiasen He, Marc Garcia-Moure, Juan Fueyo, Candelaria Gomez-Manzano
Journal: Neuro-Oncology (2024)

Abstract Despite aggressive therapeutic interventions, glioblastoma patients face a median survival of seven months after tumor recurrence. Alarmingly, there has been no improvement to the standard of care for two decades, and patients still receive toxic doses of radiation and chemotherapy, rendering many unable to perform daily functions. An emerging approach, oncolytic virotherapy (OV) using Delta-24-RGD, is gaining traction due to recent clinical trials (NCT00805376, NCT03178032, and NCT02798406) exhibiting robust responses in subsets of patients. While these studies demonstrated the therapeutic potential of OV, findings also indicate the early clearance of the virus, hindering the establishment of an effective anti-tumor immune response in most patients. We propose that mitigating the innate immune response against the therapeutic virus should result in improved intratumoral persistence, increasing the window of opportunity for developing an anti-tumor immune response. RNA-sequencing identified the non-POU domain containing octamer-binding (NONO) pathway as highly upregulated in syngenic glioma models and further amplified by OV treatment. In-vitro RNA sequencing and comparative analysis complemented these results to define a unique transcriptomic profile induced by adenovirus infection. LC-MS/MS identified host cGAS and adenoviral capsid proteins as candidate binding partners of NONO, which were validated using co-immunoprecipitation. Although the type I interferon cluster is deleted in most gliomas, tumor cells have a profound influence on their microenvironment through the secretion of the second messenger cGAMP. We show that NONO is required for cGAMP production, providing a mechanism to modulate antiviral responses in the tumor microenvironment during OV. Our findings underscore the significance of cGAMP shed from tumor cells in response to OV, and how NONO interacts with cGAS in the nucleus to sensor adenovirus infection. These findings uncover novel innate immunity mechanisms in gliomas and will inform the design of more efficacious oncolytic adenoviruses for glioma therapy.
RADT-36. FUNCTION-ADAPTED RADIOTHERAPY PLANNING IN THE MANAGEMENT OF HIGH-GRADE GLIOMAS: A COMPARING STUDY FOR DOSE SPARING OF SPEECH-ELOQUENT BRAIN AREAS
Authors: Christian D Diehl, Malin L Troendle, Sarah Stefanowicz, Martin Misslbeck, Leonie Kram, Maximilian Schwendner, Sebastian Ille, Bernhard Meyer, Stephanie E Combs, Sandro M Krieg
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Radiotherapy (RT) for brain tumors can induce injury of functional white matter tracts. In neurosurgery navigated transcranial magnetic stimulation (nTMS)- and diffusion tensor imaging (DTI)-based fiber tracts (FT) is an established tool to protect functional FT during tumor resection. We investigated it´s applicability in RT planning with the aim of dose reduction of language-associated fiber tracts. METHODS Preoperative, nTMS-generated and DTI-based FT of the functional left hemispheric language network of patients with language-eloquent malignant gliomas (WHO III/IV) were imported into the planning software (ARIA®) according to the DICOM standard and contoured as a risk structure. Brain shift after tumor resection was compensated using elastic fusion (Brainlab®). The treatment plans were optimized or recalculated with the aim of reducing the dose to the fiber tracts outside the planning target volume (PTV). The dosimetric evaluation was performed according to dose volume histogram parameters. RESULTS RT plans of 27 patients were retrospectively evaluated in the study. The mean dose (Dmean) to the fiber tracts was 37.3+/-11.8 Gy, with plan optimization dose was 33.6 +/- 12.2 Gy (-10.9% p&amp;lt;0.01), within the 20 Gy isodose the dose reduction to be achieved was on average - 25.0% (range 0-48.5%). The V54Gy and V20Gy were on average 40.2 +/- 23.7% and 72.3 +/- 21.1% compared to 38.2 +/- 23.5% and 58.1 +/- 23.7% (both p&amp;lt;0.01) with optimization. The Dmean of the PTV did not change (59.8 Gy vs. 59.8 Gy (p=0.5)), nor did the dose homogeneity (HI, (D5-D95)/Dp)(p=0.63)). The dose exposure of the organs at risk was within the specified dose constraints. CONCLUSION This study showed that (nTMS)- and diffusion tensor imaging (DTI)-based fiber tractography could be used in radiotherapy planning to spare language-eloquent brain areas without having to accept dose reductions within the PTV. Whether the concept of tract-based sparing of language function brings clinical benefits to patients needs to be further investigated in prospective studies.
BIOM-70. CSF TUMOR CELL (CSF-TC) DETECTION, QUANTIFICATION AND BIOMARKER ASSESSMENT HELPS IN CLINICAL MANAGEMENT OF BREAST CANCER AND NON-SMALL CELL LUNG CANCER PATIENTS HAVING LEPTOMENINGEAL DISEASE (FORESEE STUDY, NCT05414123)
Authors: Priya Kumthekar, Michael Youssef, Jonathan Yang, David Piccioni, Sue Beruti, Laura Gillis, Kelly Gordon, Barbara Blouw, Melissa Moore, Norman LaFrance, Marc Hedrick, Seema Nagpal
Journal: Neuro-Oncology (2024)

Abstract Leptomeningeal metastases (LM) or the presence of cancer cells in the cerebrospinal fluid (CSF)/pia remains a challenging disease to diagnosis and treat. Current standard of care methods to diagnose or assess treatment response of LM (Clinical Evaluation, MRI and Cytology) have limited sensitivity and specificity and are poorly quantifiable. This creates challenges for physicians to manage LM or determine the best course of treatment. The FORESEE Study was a multi-center, prospective clinical trial evaluating a novel diagnostic platform, CNSide, that aimed to overcome these challenges. The FORESEE study enrolled patients with breast or non-Small Cell Lung Cancer (NSCLC) with suspicion of or confirmed LM. CNSide can detect and quantify tumor cells in the CSF from patients with breast cancer or NSCLC having a suspicious or confirmed LM. This platform also is able to identify actionable mutations in the CSF via Fluorescent In Situ Hybridization (FISH) and next-generation sequencing. The primary end point of the FORESEE study was clinical utility and the impact of CNSide on physician treatment decisions. Secondary endpoints included evaluating the clinical performance of CNSide vs. cytology in tumor cell detection (sensitivity, specificity, PPV and NPV). The study enrolled 40 patients (22 breast cancer and 18 NSCLC). Each patient underwent standard of care diagnostic evaluations at baseline and at three follow up timepoints through their treatment. CNSide aided clinical decision making in 93% (50/54) of the clinical decisions. At baseline 39 patients were assessed and confirmed a positive LM diagnosis in 15% (6/39), a negative LM diagnosis in 8% (3/39), progression in 15% (6/39), resolution in 15% (6/39) and no progression, or resolution in 36% (14/39) of the patients. CNSide informed the specific drug selected for treatment in 26% (10/39) patients at baseline and demonstrated clinical high utility. The FORESEE data is undergoing ongoing analysis; updated analysis will be presented at the meeting.