tbuckley/cabot-search huggingface dataset:
OS11.7.A DELETION OF MONOCARBOXYLATE TRANSPORTER 1 IN MYELOID CELLS FAVOURS GLIOBLASTOMA DEVELOPMENT
Authors: S LILLO, M DERIEPPE, D BOMONT, A BURBAN, O MARTIN, M SALEH, T DAUBON
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Glioblastoma (GB) is the most aggressive tumor of the central nervous system, with a median survival of less than 15 months after diagnosis. The standard of care consists in surgical resection followed by radio-chemotherapy. However, patients are subject to a high rate of tumor recurrence, explained by an enriched immune environment in myeloid cells, which represent up to 70% of tumor weight and have immunosuppressive and/or pro-tumoral properties. GB possesses highly invasive properties due to its hypoxic and acidic core. Acidity is mainly mediated by the released of protons with lactate coming from tumor cells. Lactate is known to be responsible for immuno-metabolic modifications of immune cells in other cancers. Altogether, immunosuppressive/pro-tumoral macrophages abundancy and lactate concentration may impact tumor development and patient’s outcome. However, the specific effects of lactate on the phenotypes and functions of myeloid cells in the GB tumor microenvironment is poorly understood. MATERIAL AND METHODS The brain’s immune environment is unique. To study effects of microglia, which are resident macrophages, and of macrophages, that infiltrated brain from the bloodstream, on GB development, mouse models deficient for the lactate transporter MonoCarboxylate Transporter 1 (MCT1) either in all myeloid cells (Mct1Δmye), or specifically depleted in microglia (Mct1ΔMG) as well as constitutively depleted in lactate signalling, for the receptors GPR81 or GPR132 have been generated in both sexes. RESULTS AND CONCLUSION Disruption of lactate signalling through Gpr81 deficiency did not affect GB growth in our model. In contrast, male Gpr132 knockout mice (Gpr132-/-) displayed significantly reduced tumor volume compared to WT. ScRNA seq showed that Gpr132 is highly expressed in immune cells. Surprisingly, flow cytometry analysis of the immune infiltrate revealed no significant difference in in bone-marrow-derived or microglia tumor-associated macrophages (BM-TAMs vs MG-TAMs), suggesting that lactate signalling through Gpr132 regulate tumor growth with minimal influence of immune system. ScRNAseq also showed that Mct1 is expressed in myeloid cells. Then, we investigated the role of Mct1 by using the myeloid-specific deficiency model (Mct1Δmye). In vivo experiments revealed a sex-dependent effect in Mct1Δmye mice compared to control, with males exhibiting significantly larger tumors than WT mice. Interestingly, in vitro respiration assays demonstrated that Mct1Δmye BMDMs have a lower respiration rate on lactate compared to controls. For Mct1Δmye, a detailed analysis of the metabolic differences between WT and Mct1Δmye BMDMs is currently under investigation. These findings suggest intriguing regulatory roles of lactate signalling and transport on GB tumor growth, with a potential sex-specific responses mediated by Mct1 and lactate flux.
OS07.5.A MULTI-MODAL EXAMINATION OF SPATIAL HETEROGENEITY IN THE ASTROCYTOMA MICROENVIRONMENT
Authors: T Lu, L Freytag, J Moffet, J Kriel, J Whittle, S Freytag, S A Best
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Astrocytoma is a diffuse and heterogeneous glioma that infiltrates the brain. Despite post-operative therapy including radiation and chemotherapy, 52% of patients’ tumours recur within five-years of surgery. These tumours are characterised by mutations in the IDH1 or IDH2 gene that confer metabolic alterations, most notably the production of the onco-metabolite 2-hydroxyglutarate. To reveal the metabolic alterations and their upstream regulation across the heterogeneous tumour microenvironment, we applied spatial metabolomics and spatial transcriptomics to sequential sections from resected tumour samples of patients with low grade astrocytoma. METHODS Spatial assessment of heterogeneity was performed on serial sections using spatial metabolomics (atmospheric pressure MALDI-TOF) and spatial transcriptomics (10X Genomics Xenium). This necessitated extensive optimisation of image registration across modalities and sequential sections to create three dimensional models to deeply interrogate heterogeneity within tumours. RESULTS Combining spatial transcriptomics and spatial metabolomics across 8 matched sequential slices of the same patient tumour, enabled the identification of metabolic niches associated with distinct cell type composition and transcriptional regulation. Strikingly, normal domains that were present at the leading edge of tumours could be identified both metabolically and transcriptomically. CONCLUSIONS Understanding the heterogeneity of astrocytomas on a spatial level reveals unique domains and organisation of tumour and immune cell types. Matching these transcriptomic and cell state information with metabolic insights leads to pathway insights that will be essential to the identification of druggable targets. Our pipeline combining spatial transcriptomics and metabolomics with tissue histology reveals these biologically important domains.
OS12.5.A IMPROVING HEALTH EDUCATION FOR BRAIN TUMOR PATIENTS AND RELATIVES THROUGH ANIMATED AND VISUAL INFORMATION
Authors: M C Baas-Thijssen, C O Nogarede-Bloemendaal, C S Docter-Kerkhof
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Brain tumor patients interact with a wide range of healthcare professionals. It is important that they receive simple and unequivocal information about what awaits them. This contributes to shared decision making, an individual treatment plan and informed consent. Providing information becomes challenging when people are communicatively vulnerable, i.e. when they are ill or experience intense emotions. A high number of brain tumor patients are communicatively vulnerable because they have cognitive deficits or language impairments. Information processing may become slower because of the tumor and/or treatment. In 2023 the neuro-oncology task group of OncoWest, a network in the west of the Netherlands, prioritized the improvement of health care education for patients with a primary brain tumor. MATERIALS AND METHODS Visual and spoken information combined was considered best for brain tumor patients, including those with low literacy. A graphics agency was approached to create animations and a project team was assembled. The team consisted of two nurses, a clinical linguist and a communication advisor. They devised the content and texts for three main topics: care process, treatments and consequences. Texts were written in B1, a language level understood by the majority of Dutch citizens. Other factors were also taken into account, such as length of sentences, use of active tense and total duration of the videos. The texts were then reviewed by specialists in the field of neuro-oncology, and patients. A voice actor finally did the voiceover. Clinical linguists gave intermediate feedback on the animation videos. The videos still seemed too complex and fast for individuals with aphasia. Therefore, an additional tool was developed for people with aphasia as to provide extra written information, illustrated by stills from the videos. A clinical linguist simplified the text and bolded important words. RESULTS Three animation videos were developed of about three minutes each, all freely accessible, with explanation and information about 1) the care process from initial complaints to diagnosis, 2) possible treatments surgery, radiotherapy, chemotherapy and best supportive care, 3) symptoms and consequences of the disease. Furthermore an interactive pdf was made available for patients with aphasia and could be printed. CONCLUSION We described the development of clear, easily accessible visual information for brain tumor patients. The information is now available for patients, including everyone around the patient, which will hopefully increase their understanding and health care process. We hope to promote and evaluate the use of these materials in the near future.
P01.10.A INVESTIGATING GLIOBLASTOMA BIOMARKERS IN THE INFILTRATION ZONE: TOPOGRAPHIC LINKS TO AN EARLY RELAPSE
Authors: M Barak, J Brychta, M Hendrych, T Holecek, K Holikova, T Kazda, M Hermanova, J Sana, R Jancalek
Journal: Neuro-Oncology (2024)

Abstract Glioblastoma, IDH-wildtype WHO Grade 4 (GB), is the most common primary malignant brain tumor. Despite significant advancements in surgical techniques allowing for a greater extent of resection, the use of targeted radiotherapy along with the application of novel anticancer drugs, GB remains an incurable disease with a median survival of 16 months. One of the key factors contributing to the development of therapeutic resistance and recurrence is the intratumoral heterogeneity of GB. Although surgical therapy aims at maximal safe resection with the goal of gross total tumor resection (GTR) when feasible, a considerable heterogeneous residual tumor population remains at the resection margin. These residual tumor populations encompass various genomic, epigenetic, and microenvironmental variations, creating a pool from which treatment-resistant clones can emerge and subsequently become a source of GB recurrence. This pilot study aims to analyze the molecular characteristics of these high-risk cell populations in the peritumoral infiltration zone using next-generation sequencing (NGS), with the objective of identifying driving factors contributing to early relapse.
JS05.7.A TRAF7 WD40-DOMAIN MUTATIONS DRIVE MENINGIOMA TRANSDIFFERENTIATION AND INTRATUMOR HYPEROSTOSIS
Authors: C D Eaton, E Goldschmidt, Z Chen, D R Raleigh
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Meningiomas are the only primary tumors that form lamellar, hyperostotic bone in the tumor microenvironment, but mechanisms that drive meningioma-induced hyperostosis (MIH) are incompletely understood. Clinical observations suggest TRAF7 short somatic variants (SSVs) are enriched in skull base meningiomas, and that SSVs targeting the TRAF7 WD40-domain may be associated with MIH. Here we use single-cell RNA sequencing and lineage tracing approaches to study regionally distinct samples from meningiomas with intratumor hyperostosis. Integrating bioinformatic data with mechanistic and functional studies across regionally distinct primary meningioma cell cultures, our results suggest that TRAF7 mutations are heterogeneous in individual meningiomas. Moreover, we find that TRAF7 WD40-domain mutations drive meningioma cell transdifferentiation into an osteoblast-like state that is associated with mineralization in vitro and MIH in vivo. MATERIAL AND METHODS Single-cell RNA sequencing and mitochondrial alteration enrichment from single-cell transcriptomes to establish relatedness (MAESTER) lineage tracing was used to define cell types, cell states, and evolutionary trajectories from 10 human samples. Regionally distinct primary meningioma cell cultures (n=6) were derived from hyperostotic or non-hyperostotic areas from 3 meningiomas with MIH and modified to stably express CRISPR interference machinery for mechanistic and functional studies. Targeted next-generation DNA sequencing, QPCR, immunofluorescence, cell proliferation, and mineralization assays with alizarin red stains were used to define how TRAF7 WD40-domain mutations influence meningioma cell fate. RESULTS Single-cell transcriptomics and lineage tracing identified a meningioma cell cluster that was enriched for bone-associated genes early in tumor development. DNA sequencing of regionally distinct meningioma samples and primary meningioma cell cultures revealed intratumor heterogeneity in TRAF7 WD40-domain mutations that correlated with MIH. Meningioma cell cultures were validated using DNA methylation profiling and SSTR2A expression. Only cell cultures from intratumor regions with MIH expressed RUNX2, SP7, or ALPL, and only cell cultures from intratumor regions with MIH underwent mineralization in vitro. Suppression of mutant TRAF7 using sgRNAs blocked in vitro mineralization, and media from meningioma cell cultures from intratumor regions with hyperostosis induced mineralization of TRAF7 wildtype meningioma cell cultures in vitro. CONCLUSION These data demonstrate that TRAF7 WD40-domain mutations drive meningioma transdifferentiation and intratumor hyperostosis, and shed light on fundamental mechanisms underlying lamellar bone formation.
P01.11.B PATIENT-DERIVED GLIOBLASTOMA CELLS ARE CAPABLE OF FORMING TUBE-LIKE STRUCTURES IN VITRO SUGGESTIVE OF VASCULOGENIC MIMICRY
Authors: K Maddison, N A Bowden, M C Graves, M Fay, P A Tooney
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND The tube formation assay (TFA), widely used to assess the angiogenic ability of endothelial cells in vitro, involves plating endothelial cells on a basement membrane matrix layer that promotes the differentiation of the cells, observed as the formation of tubule-like structures. The extent and characteristics of the tubule network are influenced by cell seeding density, addition of growth factors, and the composition of the basement membrane matrix. Tube formation by tumour cells in vitro is considered to be an indicator of the ability of these cells to undergo vasculogenic mimicry (VM), the process by which tumour cells form functional vessel-like structures. The TFA has therefore been used to assess VM in various tumours, including glioblastoma. However, aspects of the TFA, including seeding density, basement membrane matrix, media composition, and imaging timepoint, vary greatly between previous studies of VM in glioblastoma, resulting in difficulty comparing results between studies and uncertainty relating to the conditions under which glioblastoma cells may undergo tube formation. We therefore aimed to assess the tube formation ability of multiple glioblastoma cell lines assayed under the same conditions. MATERIAL AND METHODS Twelve patient-derived glioblastoma cell lines were plated for TFAs at multiple seeding densities in serum-free media on a 150µL/cm2 layer of growth factor-reduced (GFR) Matrigel. Cells were imaged 2-hourly for 24 hours using an Incucyte SX5 Live-Cell Analysis Instrument in order to determine the tube formation ability and optimal seeding density of each cell line. Human umbilical vein endothelial cells (HUVECs) were used as a positive control. The Angiogenesis Analyzer plugin for ImageJ was used to quantify number of tubules, average tubule length, tubule area, and number of branch points for HUVECs and tube forming glioblastoma cells. RESULTS Three of the 12 glioblastoma cell lines tested were considered capable of in vitro tube formation, consistently forming tubule-like networks that morphologically resembled those formed by HUVECs within 24 hours of plating for a TFA. Network characteristics differed between HUVECs and glioblastoma cells, with the glioblastoma cells generally forming a higher number of shorter tubules, and therefore having a higher number of branch points. This did not correspond to a larger total tubule area, which was comparable between the HUVECs and glioblastoma cells. CONCLUSION A subset of patient-derived glioblastoma cell lines are able to form tube-like structures in vitro when grown in serum-free media on GFR Matrigel. Further experiments assessing additional TFA conditions and subsequent analyses of gene and protein expression in tube-forming glioblastoma cell lines may provide further insight into the mechanisms by which VM may be occurring.
OS05.6.A RADIOLOGICAL TREATMENT-ASSOCIATED CHANGES IN GLIOBLASTOMAS WITH OR WITHOUT AN MGMT PROMOTER-METHYLATION TREATED WITH CILENGITIDE: REVIEW OF THE EORTC CENTRIC AND CORE STUDIES
Authors: C M Flies, M Friedrich, P Lohmann, K van Garderen, M Smits, J C Tonn, M Weller, N Galldiks, T J Snijders
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Radiological progression during follow-up of patients with glioblastoma after treatment can result from progressive disease (PD) or treatment-associated changes such as pseudoprogression. Previous studies reported higher rates of treatment-associated changes in patients with an O6-methylguanine DNA methyltransferase (MGMT) promoter-methylated glioblastoma. We reviewed patients from two prospective, randomised EORTC studies with an MGMT promoter-methylated (CENTRIC) or -unmethylated (CORE) glioblastoma who were treated with standard temozolomide chemoradiation with or without the integrin inhibitor cilengitide. The addition of cilengitide did not improve survival. We previously reported on treatment-associated changes in the CENTRIC study. We now assessed the rate of treatment-associated changes for all patients in relation to the MGMT status, cilengitide exposure, and timing after radiotherapy. MATERIAL AND METHODS Patients with three or more MRI follow-up scans were included. We applied the modified RANO criteria of 2017. Preliminary PD (PPD) was defined as a 25% or more increase of the sum of perpendicular diameter (SPD) or a new or increasing contrast-enhancing lesion compared to baseline or nadir. Confirmed PD was defined as a further 25%- or more increase of the SPD or as a new lesion outside the radiation field. According to the RANO criteria 2.0 of 2023, we classified patients with PPD and no further follow-up due to clinical progression as PD. Treatment-associated changes were defined as stabilisation or partial/complete regression after PPD. Survival of patients with treatment-associated changes was compared to those with PD. RESULTS Follow-up was available for 424 patients from the CENTRIC and for 181 patients from the CORE study. PPD rates were 65% (274 of 424) in methylated tumours, and 86% (155 of 181) in unmethylated tumours. This resulted in treatment-associated changes in 32% (88 of 274) and 17% (27 of 155). Treatment-associated changes were more common in the first three months after radiotherapy (28% (CORE) and 54% (CENTRIC) of all PPD), in patients with tumours with MGMT promoter methylation (relative risk (RR), 1.8; 95%-confidence interval, 1.3-2.7; P=0.002), and after cilengitide (RR, 1.4; 95%-CI, 1.02-1.8; P=0.038). In addition, late treatment-associated changes after six months after radiotherapy were also observed (9% (CORE) and 13% (CENTRIC)). In both studies, patients with treatment-associated changes lived significantly longer than patients with PD (P=0.044 (CORE); P=0.003 (CENTRIC)). CONCLUSION The rate of treatment-associated changes varied with timing after radiotherapy, MGMT status and the addition of cilengitide. The role of integrins in the pathophysiology of treatment-associated changes needs to be elucidated further.
OS05.7.A RADIATION-INDUCED CONTRAST ENHANCEMENT AFTER PROTON THERAPY IN PATIENTS WITH GLIOMAS IN THE PRO-CNS STUDY
Authors: K Werlenius, M Agrup, A Flejmer, H Gojon, F Jakobsson, P Bergström, L Dahl, F Parcaoglu, M Strandéus, S Kinhult, E Morhed, M Gustavsson, K Modin, L Heggebø, P Witt Nyström, H Rylander, A Store Jakola, P Brandal, M Blomstrand
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Although proton radiotherapy has been used in a large scale for quite some time, published data from trials confirming the safety of proton therapy are still scarce. Yet, there are indications of radiation induced contrast enhancement (RICE) being more common after proton radiotherapy than photon radiotherapy. MATERIAL AND METHODS Between August 2015 and August 2020, adult patients receiving proton therapy for primary CNS tumours at the Skandion clinic in Sweden were invited to PRO-CNS, a prospective multicentre observational cohort study. We identified 120 patients with glioma WHO grade 1-3 in the PRO-CNS study. The patients received a total dose of 50.4 Gy (RBE), 54 Gy (RBE) or 59.4-60 Gy (RBE) in 1.8-2.0 Gy (RBE) fractions. Discrimination between RICE and true tumour progression was assessed by experienced neuroradiologists and neurooncologists. So far, only the 45 patients from Gothenburg have been analysed. RESULTS Preliminary data from the Gothenburg cohort show RICE in 70% of patients receiving a dose of 59.4 Gy (RBE). This is a considerably higher incidence of RICE than previously reported in patients treated with photons to the same dose. For comparison, 18% of patients receiving 50.4 Gy (RBE) and 21% receiving 54 Gy (RBE) developed RICE. Furthermore, RICE seemed to be slightly more common among patients treated for oligodendroglioma than astrocytoma, but the numbers are too small to draw conclusions. Analysis of the whole cohort of 120 patients is ongoing with the intention to be presented in 2024. CONCLUSION Our preliminary results raise concern on toxicity after proton treatment to 59.4 Gy (RBE) in glioma patients. These are preliminary results and further evaluation is needed.
JS05.6.A THE PROGNOSTIC IMPACT OF CDKN2A/B HETEROZYGOUS DELETIONS IN MENINGIOMA- INSIGHTS OF A MULTICENTER ANALYSIS
Authors: F M Ippen, T Hielscher, A Patel, K Göbel, D Friedel, S L N Maas, A von Deimling, W Wick, A K Suwala, F Sahm
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Meningiomas are one of the most common primary brain tumors. Homozygous deletions of CDKN2A/B have reliably been shown to confer an increased risk of progression. However, the role of heterozygous CDKN2A/B deletions remains less clear. MATERIAL AND METHODS DNA methylation data, copy-number information and mutation data were generated on a multicenter cohort of meningiomas for a total of 970 samples. The CDKN2A/B locus was determined manually for each individual case in relation to whole chromosomal or larger segmental losses and gains in the chromosomal profile. Survival probabilities were assessed using the Kaplan-Meier method. RESULTS A total of 970 meningioma cases were identified with 30 homozygous and 114 heterozygous CDKN2A/B deletion cases, 826 cases had balanced CDKN2A/B. Heterozygous CDKN2A/B deletions in general did not confer an increased risk of progression compared to CDKN2A/B balanced cases (p= 0.074). However, segmental heterozygous losses of 9p, encompassing CDKN2A/B, yielded a significantly worse prognosis when compared to meningiomas CDKN2A/B-balanced (p= 0.002) and in contrast to focal heterozygous deletions (p= 0.523). Segmental heterozygous 9p deletions encompassing CDKN2A/B were significantly more frequently associated with a higher amount of copy number variations (CNVs) than focal losses. CONCLUSION Segmental heterozygous CDKN2A/B deletions do confer an increased risk of progression, but focal heterozygous CDKN2A/B deletions do not. The signal for segmental deletions may not be locus-specific but just one representation of the generally instable genome of aggressive meningiomas.