bluuebunny/crossref_metadata_2025_split huggingface dataset:
OS11.7.A DELETION OF MONOCARBOXYLATE TRANSPORTER 1 IN MYELOID CELLS FAVOURS GLIOBLASTOMA DEVELOPMENT
Authors: LILLO S , DERIEPPE M , BOMONT D , BURBAN A , MARTIN O , SALEH M , DAUBON T 
Published: October 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.
P01.09.B IDENTIFICATION OF TIME-DEPENDENT PHENOTYPIC SHIFTS IN PATIENT-DERIVED GLIOMA STEM-LIKE CELLS AFTER CHEMORADIOTHERAPY
Authors: Van Eupen L , De Visser Y , Bravo Gonzalez-Blas C , Cole B , Loers J , Derweduwe M , Claeys A , Tabury K , Primac I , Vermeirssen V , De Smet F , Quintens R 
Published: October 2024

Abstract

BACKGROUND
Glioblastoma remains among the deadliest tumors without a suitable cure. The failure of virtually all clinical trials from the past 20 years can be attributed to the extensive (epi)genetic and phenotypic heterogeneity within and across GBM patients but also to the extensive plasticity of cancer stem-like cells that can easily adapt and drive resistance to treatment. A fundamental understanding of this plasticity and its underlying mechanisms is still largely missing, but it remains pivotal to identify suitable targets that can prevent cells from surviving treatment.

METHODS
In this project, we start by defining the landscape of standard-of-care-induced plasticity using multi-omic profiling of patient-derived glioma stem-like cells (PDGSCLs) after radiation therapy (RT, 2 Gy) and temozolomide (TMZ, 150 μM). In a pilot experiment, bulk RNA sequencing was performed on six PDGSCLs at different time points after RT+TMZ (16 hours, 3 days, 10 days). A single-cell RNA sequencing (scRNAseq) experiment has been set up in a similar fashion, including the 16-h and 3-d time points.

RESULTS
Analysis of the bulk transcriptomic data, including module scoring based on transcriptional cell states defined by Neftel et al. (2019), revealed a time-dependent shift in phenotype after treatment. Two of the six PDGSCLs did not show clear indications of plasticity, while two others showed minor shifts in phenotype and two PDGSCLs displayed clear shifts towards the mesenchymal (MES) phenotype, with one of them reverting back to its original state after 10 days. Pathway analysis additionally indicated an upregulation of MES-associated processes including ameboidal-type cell migration, cell-substrate adhesion and wound healing, with differentially upregulated pathways between sensitive and resistant PDGSCLs that both displayed MES-shifts.

CONCLUSIONS
Our results confirm that treatment can induce phenotypic changes in PDGSCLs in a cell line-specific manner, suggesting different mechanisms can lead to the enrichment of the same phenotype. Moreover, our time course data highlights that the timing of read-out is important as well, and comparing tumors at diagnosis vs. at recurrence might not suffice to fully understand this plastic behavior, for which these intermediate time points are more relevant. The scRNAseq experiment is currently ongoing and will inform on the gene regulatory networks responsible for the observed shifts while also highlighting the heterogeneity within these PDGSCLs with greater resolution, as seen in the patient population. This project is funded by FWO (11B2323N) and the Foundation against Cancer (F/2022/2026).
P01.14.B SYNGN: A NOVEL EPIGENETIC PLATFORM TO DISCOVER PATIENT-SPECIFIC DISEASE MECHANISMS AND DRUGGABLE TARGETS IN GLIOBLASTOMA
Authors: Marino S , Vinel C , Constantinou M 
Published: October 2024

Abstract

BACKGROUND
The alteration of the glioblastoma genome by epigenetic mechanisms that share functions with normal developmental processes, such as self-renewal and fate specification of neural stem cells (NSC), is a key piece of evidence that links brain cancer pathogenesis with dysregulated stem cell functions. A patient-specific comparison of glioblastoma stem cells (GSC) with NSC, a putative cell of origin of at least a proportion of these tumours, is not feasible as patient-matched endogenous NSC are not surgically accessible and all epigenetic studies in glioblastoma have so far compared epigenetic changes of different tumours with each other or to comparators obtained from foetal brains or an unrelated donor. We reasoned that availability of syngeneic GSC and NSC pairs would allow to identify crucial epigenetic differences on a patient-specific basis and would provide essential therapeutic contrast to define disease-and patient-intrinsic biomarkers of drug response that are less confounded by germline variation.

MATERIALS AND METHODS
We have derived GSC from IDH-wildtype glioblastoma and harnessed state-of-the-art stem cell technologies to generate patient-matched fibroblast-derived EPSC, which were induced to NSC (iNSC). We generated transcriptome, DNA methylome, ChIP-Seq (H3K4me3, H3K27ac, H3K3me3, H3K27me3) and ATACSeq datasets for 10 GIC/iNSC pairs.

RESULTS
Comparative integrated analysis has shown that redistribution of selected histone marks as well as shifts in chromatin states across the genome identifies differentially expressed genes, including novel druggable regulatory mechanisms in GSC, which are specific of the neoplastic context. In particular, we identified METTL7B as an essential regulator of lineage specification and plasticity in human glioblastoma, with impact on both tumour size and invasiveness in an in vivo xenograft model. Single cell transcriptomic analysis of these tumours and of cerebral organoids derived from expanded potential stem cells (EPSCs) overexpressing METTL7B reveal a regulatory role for the gene in the neural stem cells-to-astrocyte differentiation trajectory. Mechanistically, METTL7B downregulates the expression of key neuronal differentiation players, including SALL2, via post-translational modifications of histone marks.

CONCLUSION
SYNGN is an epigenetic platform which can identify novel disease mechanisms and druggable targets in glioblastoma.
P02.02.A AN MRI-LSM PLATFORM TO ASSESS BLOOD-BRAIN BARRIER DISRUPTION AND BIODISTRIBUTION OF IMMUNOTHERAPIES IN EXPERIMENTAL GLIOMA
Authors: Scheck J G , Boztepe B , Heinz L , Sturm V , Pan C , Fischer M , Heiland S , Winkler F , Wick W , Schregel K , Abdollahi A , Platten M , Bendszus M , Weidenfeld I , Breckwoldt M O 
Published: October 2024

Abstract

BACKGROUND
The inherent resistance of glioma including the recent failure of immune checkpoint blockade to prolong survival in glioma has partly been attributed to tumor heterogeneity leading to insufficient drug availability. Magnetic resonance imaging (MRI) is the main clinical modality to monitor tumor growth and treatment response but cannot assess drug availability within the tumor microenvironment (TME). To this end, we developed a platform to assess blood-brain barrier disruption utilizing high field multiparametric MRI and correlative light sheet microscopy (LSM) to investigate the underlying mechanisms of response and resistance towards immunotherapy in brain tumor models.

MATERIAL AND METHODS
Orthotopic gliomas were grown in the syngeneic GL261 or SB28 mouse glioma models. Longitudinal contrast enhanced multiparametric MRI was performed weekly after baseline. To correlate drug distribution with BBB-D and the microvasculature, mice either received a single dose of fluorescently labelled anti-PD1 or TLR7 agonist encapsulated nanoparticle CDNP-R848 at different tumor stages. After 24 hours circulation time, vasculature was labelled through lectin-FITC perfusion. Brains were cleared with fDisco and LSM was performed. Images were segmented with Ilastik and further analysis was carried out in Imaris, Fiji and VesselVio.

RESULTS
In Gl261 gliomas we achieved a response rate of 87.5% to CDNP-R848, as previously established by our group, whereas SB28 tumors were fully resistant to CDNP-R848 validating the strong immunotherapeutic resistance of SB28. In both glioma models, immunotherapies were CNS-penetrant and reached the TME without off targeting, while showing cellular specificity for myeloid cells or T cells, respectively. Gadofluorine M and Gd-DOTA allowed the assessment of different spatio-temporal patterns of BBB-D. Microbleedings as assessed by T2* imaging and BBB-D as assessed by perfusion imaging were more prominent in SB28, indicating pronounced heterogeneity in the SB28 model, likely contributing to its resistance. GfM and perfusion MRI were strongly correlated with drug distribution, indicating that these MR parameters can predict drug distribution in the TME.

CONCLUSION
Our correlated MR-LSM approach therefore allows the assessment of the 3-dimensional biodistribution of checkpoint inhibitors and immunotherapeutic NP in the TME in relation to BBB-D. By validating MR-based imaging biomarkers, we aim to non-invasively predict drug availability in the complex TME of glioma.
P02.11.A IMMUNE CELLS SUBPOPULATIONS IN PERIPHERAL BLOOD IN PATIENTS WITH GLIOBLASTOMA
Authors: Roncelli F , Boselli D , Snider S , De Domenico P , Braga M , Bisoglio A , Villa C , Gentner B , Mortini P , Gagliardi F 
Published: October 2024

Abstract

BACKGROUND
Glioblastoma is the deadliest type of primary brain tumors. Tumor microenvironment characterization may provide new insights in understanding disease and the balance between inflammatory and suppressor cells and represent a key factor in tumor-microenvironment interaction. This study aims at characterizing peripheral immune cells subpopulations in glioblastoma patients.

MATERIAL AND METHODS
We analyzed peripheral blood mononuclear cells (PBMC) from 57 patients with newly diagnosed glioblastoma who underwent surgery in Neurosurgery department from 2019 to 2023. Blood sample was taken before surgery and PBMC were stored in Institutional Biobank. Clinical and radiological features and steroid dosage at sample time were recorded. For flow cytometry analysis, two panels of antibodies were designed, one for myeloid and one for lymphoid cells. Acquisition was performed with BC CytoFLEX LX and CytExpert software and data were processed with FCS Express 7. Statistical analysis was performed with SPSS 28.

RESULTS
Survival data were available for 52 patients: the mean overall survival (OS) was 15.98 months. A Cox regression analysis was performed to identify any prognostic impact of subpopulations, on which steroids’ influence was checked. A small effect was noted for monocytes (HR 1.055, p 0.018) and CD11b+/CD33+ cells including peripheral myeloid-derived suppressor cells (MDSC, HR 1.044, p 0.055), both influenced by steroids. A stronger effect was noted for immature NK cells (HR 0.198, p 0.029), uninfluenced by steroids. A significant correlation was found between immature NK cells and ECOG performance status (PS), with higher levels in patients with lower ECOG (p 0.029). MDSC and CD8+ T cells were more represented in patients with necrosis on MRI while patients with midline shift showed higher MDSC and lower immature NK cells. FLAIR volume was positively correlated with mature NK while MDSC and mature NK showed a correlation near to significance with the difference between FLAIR and contrast-enhancing volume.

CONCLUSION
These results are promising in identifying subpopulations in peripheral blood with a putative role in patients’ OS. Higher immature NK cells correlate with higher PS at surgery and are associated with increased OS. On the other hand, monocytes and MDSC correlate with radiological parameters such as midline shift, necrosis, and FLAIR volume. Further analysis on larger sample and longer follow-up is required to confirm these promising results.
P06.04.A FIRST IN HUMAN - TARGETING ANDROGEN RECEPTOR FOR GLIOBLASTOMA THERAPY
Authors: Lavon I , Mordechai A , Lossos A 
Published: October 2024

Abstract

BACKGROUND
Glioblastoma represents a significant therapeutic challenge due to its aggressive nature, necessitating the development of effective targeted therapies. In a pivotal study, the amplification of the androgen receptor in 56% of glioblastomas was observed, shedding light on its therapeutic potential. Through extensive research, our team demonstrated the efficacy of the androgen receptor antagonist, enzalutamide (Xtandi), in prolonging lifespan in a mouse model of human glioblastoma. Collaborating with the Cyclotron and PET/CT teams, we established [18F]-FDHT PET/CT imaging, facilitating real-time detection of androgen receptor expression within brain tumors and enabling precise patient selection for targeted therapy.

METHODS
To proceed with a clinical trial, we conducted several steps. Initially, we examined the pharmacokinetics of enzalutamide and temozolomide, both as monotherapy and in combination, over multiple time points up to 96 hours, analyzing plasma and brain samples by LC-MS/MS. Additionally, we assessed the efficacy of PET/CT imaging for therapy response monitoring. After confirming androgen receptor expression via PET scan, patients underwent a 10-day regimen of escalating doses of the androgen antagonist Xtandi, administered daily, followed by a second PET scan.

RESULTS
In the pharmacokinetic analysis, we found that the half-life (t1/2) of enzalutamide remained consistent in both plasma and brain tissue when combined with temozolomide, compared to monotherapy. Notably, the t1/2 of temozolomide increased significantly when administered concurrently, rising from 1.8 to 4.45 in plasma and from 0.88 to 7.25 in brain tissue, respectively. These results informed the clinical trial protocol design. Regarding the PET/CT study, the outcomes were promising: two potential responders identified through imaging received either 40 or 80 mg of Xtandi. The patient who received 80 mg exhibited a significant reduction in tracer uptake after ten days of treatment, accompanied by tumor shrinkage and tangible improvements in mobility and quality of life, highlighting the transformative potential of our approach.

PLANS AND DISCUSSION
Encouraged by these results, we initiated a clinical trial to determine the safety and tolerability of Enzalutamide in conjunction with radiotherapy (RT) and temozolomide (TMZ), to assess clinical response using Response Assessment in Neuro-Oncology (RANO) criteria and to characterize the pharmacokinetics of Enzalutamide combined with TMZ. We have recently enrolled two patients for this study, and eagerly anticipate presenting the results of these participants, along with potentially others, during the forthcoming meeting. With the potential to rapidly translate these findings into clinical practice, our fast-track trial represents a beacon of hope for Glioblastoma patients worldwide.
P07.04.A THE LOSS OF THE X CHROMOSOME IN THE CONTEXT OF THE MALIGNANCY OF MENINGIOMAS
Authors: Berghaus N , Savran D , Hielscher T , Schrimpf D , Herold-Mende C , Wick W , von Deimling A , Sahm F 
Published: October 2024

Abstract

BACKGROUND
In recent years, molecular markers have become increasingly important in the diagnosis and risk assessment of brain tumours. Besides mutations and methylation, this also includes copy number variations (CNVs). It is well known that CNVs contribute to cancer initiation, progression and therapeutic resistance. Investigating the most common primary intracranial tumours in adults, meningiomas, several studies propose new stratification systems with a more accurate risk prediction than the WHO grading. Several of these approaches combine morphology, methylation, or both, with CNV status to derive a more precise risk assessment. However, a common shortcoming is the absence of separate analyses based on the sex of the patients or the inclusion of the X chromosome.

MATERIAL AND METHODS
A cohort of over 6000 meningiomas was stratified and analysed regarding the loss of the X chromosome. Further, a differential methylation analysis was conducted based on EPIC v1 data.

RESULTS
In general, meningiomas from females displayed a loss of chromosome X more than three times more often than tumours from males (p = &lt;0.001) and were significantly associated with a more malignant classification, affecting both the WHO classes and the methylation classification. Calculating oncogenetic trees, females and males share the loss of chr22q as first node followed by a loss of chr1p but only in females, the loss of chromosome X directly follows the high-risk CNV event “loss of chr14q”. However, not only CNVs, but also DNA methylation is a decisive factor. Therefore, a differential methylation analysis was conducted between meningiomas from females with and without a loss of the X chromosome, stratified for methylation classes. Within the methylation class (MC) ben-1, almost no difference between the two cohorts could be detected for the autosomes. In contrast, within the MC mal, the highest and significant difference was noted for a region overlapping with the RUNX3 gene (p = &lt;0.001) - indicating a higher methylation in the “noloss” subgroup. This is of special interest as RUNX3, a transcription factor, regulates gene expression, impacts the cell cycle, cell differentiation, apoptosis, tumor suppression, and cancer cell metastasis. Analyzing the MC mal regarding the X chromosome, for example, a significant difference was detected for a region overlapping COX7 (p = &lt;0.001). The mitochondrial protein COX7b has previously been linked to driving metastasis of human breast cancer cells in mice.

CONCLUSION
The findings indicate that the loss of the X chromosome in females is linked to tumor malignancy and can also be correlated with different methylation patterns.
P08.03.A CSF-BASED PROTEOMIC BIOMARKERS OF RESPONSE TO MULTI-AGENT INTRAVENTRICULAR CHEMOTHERAPY IN CNS LYMPHOMA
Authors: Mansouri A , Aastha A , Wilding H , Mikoljewicz N , de Macedo Filho L , Glantz M , Kislinger T 
Published: October 2024

Abstract

BACKGROUND
Despite promising responses to initial therapy for central nervous system lymphoma (CNSL), relapse is common and overall responses are disappointing compared to other non-CNS diffuse large B-cell lymphomas. Literature reports 1- and 3-year survival rates of 50% and 30-40% respectively, with standard treatment. Incorporation of multi-agent intrathecal chemotherapy (MAITC) alongside systemic therapy is novel but not widely adopted. Biomarkers predictive of response could help select patients most likely to benefit. Our retrospective analysis of CNSL patients treated with MAITC between 2015-2021 indicates a significant overall survival advantage. Cerebrospinal fluid (CSF) is a less invasive alternative for diagnosis and management of CNSL compared to traditional biopsies, while also reducing sampling bias. The objective of this study is to identify CSF-based proteomic biomarkers that can serve as reliable indicators of MAITC treatment response and guide CNSL management.

MATERIAL AND METHODS
Patient-matched CSF samples were banked at pre- and post-therapeutic endpoint in 22 primary and 36 secondary CNSL patients. The samples were profiled using high-throughput fluid sample protocol coupled with mass-spectrometry that only requires 30 microliters of CSF. Clinically, patients were categorized as “early responders” (objective imaging response and cytology clearance by cycle 6, both maintained until cycle 12) vs. “non responders”. Tumor burden (based on MRI and cytology) was correlated with proteomic markers to identify potential correlative markers.

RESULTS
SGCE, LCP1 and AGRN were found to reliably (AUROC 0.95, 95% CI 0.81-0.98, Sensitivity: 0.62, Specificity: 0.76) stratify patients based on MAITC response (responder vs. non-responder). Through analysis of matched pre- and post-treatment samples (&gt;3 cycles) from the same patient cohort and correlation with brain MRI and CSF cytology, we identified H3F3A, YWHAE, LCP1, CA1 and GAPDH as candidate tumor burden biomarkers (AUROC 0.9, 95% CI 0.79-1.0). Conclusion: Our low input proteomic analyses of CSF has identified candidates potentially predictive of response to MAITC along with potential tumor burden markers. Validation studies with a larger cohort and additional timepoints are currently underway.