tbuckley/cabot-search huggingface dataset:
P01.15.A SURGICAL RESECTION-INDUCED ISCHEMIA DRIVES GLIOBLASTOMA CELL PLASTICITY AND TUMOR MICROENVIRONMENT ADAPTATION
Authors: A Ballestín, J Reveilles, C Pichol-Thievend, G Bourmeau, O Anezo, V Ribecco, B Blanchard, A Pettiwala, S Leboucher, T Daubon, J van Rheenen, G Seano
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Glioblastoma IDH-wildtype (GBM) treatment involves a combination of surgical resection, radiation therapy, and chemotherapy with temozolomide. Despite the aggressive standard of care, 90% of patients experience recurrence a few months after treatment, typically marked by the regrowth of highly invasive cells spreading from the peritumoral brain resection zone. The impact of chemoradiotherapy has been studied, but the impact of microsurgical resection on the tumor microenvironment (TME) and the plasticity of GBM cells remains unknown. Hence, the objective of this work was to study histopathological and transcriptomic changes induced by microsurgical resection on residual tumor cells and TME. MATERIAL AND METHODS Syngeneic GBM cell lines CT2A and GL261 were orthotopically implanted in C57Bl6j mice brains meanwhile P3 xenografts were injected in immunosuppressed nude mice. We developed an optimized microsurgical resection protocol for GBM in mice, mirroring the steps performed in patients. In a size-matched study, mice were randomly assigned to four groups: control (pre-surgery) and 1, 3, and 7 days post-surgery. Tumor tissues were studied with a multilevel strategy composed of time-resolved bulk and single-cell RNA sequencing, immunohistochemistry and intravital multiphoton microscopy (IVM). RESULTS Our analyses showed that microsurgical resection induced pronounced proneural-to-mesenchymal transition (PMT) and stimulation of hypoxia-driven pathways in residual GB cells. Further, we detected significant changes in the TME relative to the immune response and vascular function in line with ischemia exposure, which could humper the response to treatment by altering the adequate effect and distribution of the subsequent chemoradiotherapy. CONCLUSION Microsurgical resection consequences play a crucial role in shaping the phenotypic landscape of GBM tumor cells and the TME, marked by a transient ischemic TME triggering PMT in GBM cells and potentially preventing the effective response to chemoradiotherapy.
P09.07.A EMERGING TRENDS IN NEURO-ONCOLOGY: THE RECENT ADVANCES OF AMIDE PROTON TRANSFER WEIGHTED (APTW) AND ARTERIAL SPIN LABELLING (ASL) IN BRAIN TUMOUR IMAGING
Authors: M Shah, W Awuah, V Sanker, J Tan, N Aderinto, A Ahluwalia, J Poornaselvan, P Ohenewaa Tenkorang, K Darko, T Abdul-Rahman, O Atallah, S Duvuru
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Accurate diagnosis of brain tumours is crucial for improving patient outcomes. Current diagnostic methods such as MRI and CT scans have limitations in differentiating tumour types and defining margins. Recent advances in radiological modalities, specifically Amide Proton Transfer Weighted (APTw) and Arterial Spin Labelling (ASL) imaging, offer promising avenues to overcome these challenges. MATERIAL AND METHODS A systematic review of papers published between 2000 and 2024 that met the inclusion criteria was undertaken using several databases, including PubMed, EMBASE, Google Scholar, the Cochrane Library, and Scopus. Key terms such as “amide proton transfer weighted,” “arterial spin labelling,” “neuro-oncology,” and “brain tumours” were consistently employed. RESULTS APTw and ASL techniques play pivotal roles in brain tumour diagnostics, offering unique insights into molecular composition and vascular perfusion patterns, respectively. APTw facilitates differentiation between tumour subtypes, providing crucial data on aggressiveness and therapy response, while ASL evaluates tumour vascularisation, aiding therapeutic decisions, especially for anti-angiogenic treatments. These non-invasive methods enhance patient safety and comfort compared to invasive procedures like biopsy. ASL’s efficacy in distinguishing radiation necrosis from recurrent cancer, with a sensitivity of 94%, surpasses that of FDG PET and DSC. Furthermore, APTw-CEST imaging shows promise in evaluating treatment effects and delineating tumour borders, particularly in distinguishing gliomas from meningiomas. The combination of APTw and ASL enhances diagnostic accuracy, especially in differentiating tumour types or assessing treatment response, with the “APTw-ASL mismatch” emerging as a novel biomarker for specific tumour types like pilocytic astrocytomas. However, challenges such as technical complexities and limited accessibility exist but can be addressed through standardisation and technological advancements. CONCLUSION The clinical role of APTw and ASL imaging extends beyond diagnosis, aiding in intraoperative monitoring, complication detection, and seizure prediction. Collaborative efforts are needed to refine these techniques and overcome technical challenges, ensuring their wider clinical application and reliability. Despite challenges, their integration into clinical practice could revolutionise neuro-oncology by providing valuable insights into tumour biology and guiding personalised treatment strategies. Further research and standardisation efforts are essential to maximise the clinical utility of these advanced imaging techniques.
P09.01.B 18-FET-PET ENHANCED DIAGNOSIS OF PSEUDOPROGRESSION IN GLIOBLASTOMA IS AN INDEPENDENT PROGNOSTIC FACTOR FOR OVERALL SURVIVAL
Authors: T Schmidt, Z Oezdemir, C Oster, U Sure, K Hermann, M Stuschke, C Deuschl, C Kleinschnitz, M Müther, M Glas, S Kebir
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Detecting pseudoprogression (PSP) in glioblastoma during first-line treatment remains challenging and has significant clinical implications for patient management. The detection of PSP has been shown feasible using FET-PET. The prognostic impact of FET-PET diagnosed PSP on overall survival is still uncertain, as retrospective studies provide limited insights due to the substantial differences in the distribution of prognostic factors between TP and PSP groups. This study aims to address these uncertainties by leveraging advanced analysis techniques. MATERIAL AND METHODS Patients with newly diagnosed glioblastoma (WHO 2021) who underwent chemoradiation and contrast-enhanced MRI suspected for TP and subsequent FET-PET scan at Essen University Hospital were retrospectively evaluated. The modified Response Assessment in Neuro-Oncology (RANO) criteria were used to diagnose PSP. FET-PET analysis included mean (TBRmean) and maximum tumor-to-brain ratios (TBRmax). The two groups (TP/PSP) were balanced using a propensity scoreanalysis including age at diagnosis, extent of resection, Karnofsky-Performance-Status Scale (KPS) and MGMT methylation status. Overall survival was predicted using Kaplan-Meier and multivariate analysis as well as conventional FET-PET parameters, PET/MRI volumetry, and FET/MRI-derived radiomics. An independent cohort was used for validation. Results: Out of the 165 patients analysed in this study, 38 were diagnosed with PSP. Following balancing analysis, our study cohort consisted of 40 patients (20 TP/20 PSP). Patients with PSP had a significantly longer mean overall survival (mOS) compared to those with TP (mOS TP 20.24 months; mOS PSP 33.25 months; p=0.0023). The multivariate Cox-Regression analysis confirmed PSP as a significant prognostic marker for overall survival (p=0.0153). Confirmation of these results on an independent validation cohort is pending and will be presented at the meeting.Conclusion: This study shows that PSP is an independent prognostic factor for overall survival in newly diagnosed glioblastoma patients.
P14.15.A INTRAOPERATIVE ASPIRATE TISSUE MONITORING DURING 5-ALA GUIDED HIGH-GRADE GLIOMA SURGERY
Authors: A Elomaa, S Lehtonen, M von und zu Fraunberg, F Charbel, J Luoma, M Visuri, I Haapala, J Haapasalo, E Vik-Mo, S Puustinen
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND The first-line treatment for high-grade gliomas (HGG) is maximal safe resection, which is limited by diffuse tumor margins and nearby eloquent areas. Intraoperative detection of tumor cells is improved with fluorescence-guided surgery using 5-ALA, but its visual detection is limited by blood, obstacles and weakness of the fluorescence. Aspirate tissue monitoring (ATM) of fluorescence from surgical suction waste could improve surgical performance by providing objective feedback while maintaining a natural white light anatomical view. This observational study compared the visual detection of 5-ALA fluorescence to feedback from an ATM device. MATERIALS AND METHODS Twelve (n=12) patients’ suspected HGG resection with (n=9) and without (n=3) prescribed 5-ALA were recorded while a prototype ATM, was attached to the tube of an ultrasonic aspirator. Seven (7) neurosurgeons viewed the white and blue light operation videos with and without ATM feedback and responded to a questionnaire assessing the safety and benefit-risk ratio of ATM. According to the averaged experts’ analysis, the resected tissues were categorized to visually perceivable fluorescence (yes/no) and compared to the ATM signals. RESULTS In total 42 video sequences were analyzed. The sensitivity and specificity of ATM in comparison to visual analysis was 100% and 80%, respectively. The positive predictive value (PPV) of ATM was 92% and the negative predictive value (NPV) was 100%. The ATM detected fluorescence under white light in 11 of the resected areas, whereas experts in 0 areas (p&amp;lt;0.001). 10/11 of these areas were verified to include strong visual fluorescence under blue light according to experts’ analysis. The neurosurgeons agreed that ATM appears safe and adds value to contemporary navigation techniques with good agreement (averaged overall agreement rate = 96,7%). CONCLUSIONS The ATM improved intraoperative detection of fluorescence compared to visual analysis. The safety and benefit-risk assessment depicts non-inferiority compared to visual analysis for detecting fluorescence during HGG surgery.
P02.11.A IMMUNE CELLS SUBPOPULATIONS IN PERIPHERAL BLOOD IN PATIENTS WITH GLIOBLASTOMA
Authors: F Roncelli, D Boselli, S Snider, P De Domenico, M Braga, A Bisoglio, C Villa, B Gentner, P Mortini, F Gagliardi
Journal: Neuro-Oncology (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.
P03.01.A ANDROGEN MODULATION OF TEMOZOLOMIDE SENSITIVITY IN GLIOBLASTOMA
Authors: J Plata-Bello, H Fariña-Jerónimo, R Martín-Ramírez, C Martín-Abreu, H Hagemeyer, L Medina, R González-Fernández, P Martín-Vasallo
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Androgen receptor (AR) activation appears to play a pathogenic role in glioblastoma. However, the impact of testosterone on sensitivity to temozolomide action has not been explored. The aim of the present work is to analyze the effect of testosterone on temozolomide action sensitivity on cell viability in glioblastoma. METHODS Three glioblastoma cell lines (U87-MG, U118-MG, and A172) cultured in DMEM/F12 were utilized. Various experimental conditions were applied: testosterone 100nM, bicalutamide 100uM (an AR inhibitor), and temozolomide 60ug/mL, as well as their combinations. Two control conditions were included. Cell viability was determined using the Cell Counting Kit-8 (Dojindo) at 24, 48, and 72 hours, with all experimental conditions performed in triplicate. Analysis of variance was employed to identify differences in cell viability, with Tukey correction for multiple comparisons. RESULTS Cell viability significantly increased with testosterone exposure and decreased with temozolomide treatment, as expected. The combination of temozolomide with testosterone attenuated the impact of the former on cell viability, indicating increased resistance in testosterone-exposed cells. This effect was more pronounced in U118-MG (p&amp;lt;0.001) and A172 cells (p=0.019), with a similar trend observed in U87-MG cells (p=0.312). The attenuating effect of testosterone disappeared upon adding bicalutamide in U118-MG (p&amp;lt;0.001) and A172 (p=0.015) cells, albeit to a lesser extent in U87-MG cells (p=0.085). The combination of bicalutamide and temozolomide showed a synergistic effect in reducing cell viability in all three cell lines. CONCLUSION The androgenic pathway modulates sensitivity to temozolomide action in glioblastoma, revealing potential implications for therapeutic strategies in this aggressive brain tumor.
P02.13.B IMPLEMENTATION OF A MULTIPLEXED TISSUE IMAGING PROTOCOL FOR CHARACTERIZATION OF THE TUMOR MICROENVIRONMENT IN MELANOMA BRAIN METASTASES
Authors: A Sagerer, D Westphal, M Meinhardt, A Schulz, F Meier, I Y Eyüpoglu, G Schackert, T A Juratli
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Melanoma-specific genetic changes are being identified for targeted therapy. Unfortunately, patients receiving such therapies often develop resistance and experience recurrence. Current data suggest that the tumor-specific microenvironment has a decisive influence on therapy resistance. We therefore established a multiplexed immunofluorescence staining procedure to precisely characterize the tumor microenvironment in melanoma brain metastases (BM). MATERIAL AND METHODS Co-detection by indexing (CODEX) technology relies on DNA-conjugated antibodies and the cyclic addition and removal of complementary fluorescently labeled DNA probes and has been used so far to simultaneously visualize up to 100 biomarkers in situ. It enables a deep view into the single-cell spatial relationships in tissues and is intended to spur discovery in disease and therapeutic design. Hence, CODEX was provided by Akoya Biosciences. To quickly handle a larger scale of samples, a tissue microarray (TMA) was created both of tumor bulk as well as positive and negative surgical margins. RESULTS At first, a panel of yet 30 antibodies were conjugated with its definite DNA oligonucleotide sequence (reporter). On our part, these antibodies were previously validated on conventional IHC using normal and gliotic brain along with tonsil tissue, including CD molecules (e.g. CD4, CD8, CD20, CD31, CD68), signal transducing antibodies (e.g. AKT, ERK, EGFR, IGFR and their phosphorylated isoforms) as well as tumor (e.g. HMB-45, Ki67, Melan-A) and neuronal (e.g. GFAP, NeuN, Olig2, PSD-95) markers. Subsequently, TMAs of different BM composition were generated (25 cores (1.5 mm), per slide 6x4 samples + 1 positive control). Within only a single working day TMAs were prepared and CODEX staining protocol fully assembled (single step staining to preserve sample integrity). CODEX run (3 reporter dyes imaged with complimentary barcodes) was performed overnight truly smooth. Lastly, analysis of spatial information has been received via QuPath (open source). CONCLUSION Once individually designed, multiplex fluorescence imaging platform is an easy and especially in case of TMAs fast-performing tool to gain insight into the tumor microenvironment of small sample volumes in particular. For the prediction of possible therapy resistance distinct further studies are warranted to define the potential of high throughput multiplexed imaging in a clinical routine.
P02.01.B 3-PHOTON IN VIVO IMAGING REVEALS BREAKDOWN OF MICROGLIA SURVEILLANCE UPON GLIOMA INVASION IN THE CORPUS CALLOSUM
Authors: F C Nebeling, F Fuhrmann, M Mittag, A Deli, M Stork, M Clements, C Garcia Diaz, S Parrinello, M Hölzel, U Herrlinger, P Salomoni, M Fuhrmann
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Glioblastomas are the most malignant primary brain tumors with median survival of about 17 month after diagnosis despite extensive treatment. Molecular heterogeneity and the tumor microenvironment contribute to the challenges in treating GBs. Glioma-associated microglia and macrophages, comprising 30-50% of non-neoplastic cells in the microenvironment, play a crucial role in facilitating tumor growth and inducing tissue necrosis. However, the intricate interplay between these immune and glioma cells remains poorly understood. This study focuses on understanding the dynamic role of microglia during glioblastoma invasion at the tumor’s invading front in corpus callosum. MATERIAL AND METHODS In order to investigate glioma and microglial dynamics, we use an autochthonous model of mesenchymal GBs employing a CRISPR/Cas mediated approach in recipient Cx3Cr1 knock-in mice. Previous studies using two-photon in vivo imaging were limited to superficial cortical regions, hindering investigations into deeper brain areas like the corpus callosum. Recently, three-photon microscopy has emerged as a powerful tool to image between 1100-1600µm deep into the intact brain. RESULTS By implanting chronic cortical windows and taking advantage of three photon in vivo imaging, we reveal differential regulation of microglial motility based on glioma infiltration levels in the corpus callosum. Moreover, we find distinct clusters of microglial movement in dependence to the distance of tumor cells. Conclusion: This approach provides insights into microglia-glioma interactions at the invading front in the corpus callosum, offering a valuable tool for studying deep-seated cellular dynamics and identifying potential therapeutic targets. Funding Source: CANcer TARgeting (CANTAR)
P12.06.A DESCRIPTIVE AND FUNCTIONAL ASSESSMENT OF MHC I-BOUND PEPTIDES PRESENTED ON EXTRACELLULAR VESICLES OF GLIOBLASTOMA CANCER CELLS IN RESPONSE TO ONCOLYTIC VIRUS IMMUNOTHERAPY
Authors: A Bronisz, K Kiel, A Balakrishnan, M Przybylski, E Chiocca, J Godlewski
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Immunopeptide-based therapies offer the potential for cancer care breakthroughs, necessitating effective mass spectrometry utilization in preclinical research. Despite advancements in identifying cancer-specific antigens, personalized medicine faces challenges due to antigen scarcity, demanding heightened detection sensitivity. Additionally, limited patient tissue availability requires expanding antigen-presenting material through cell culture techniques. MATERIAL AND METHODS Disparate treatment responses are challenging for heterogeneous glioblastoma. Integrating next-gen sequencing and ex vivo patient stem-like cell (GSC) culture, our model mirrors disease heterogeneity and patient-specific responses to HSV1 oncolytic virus (OV) immunotherapy currently under clinical trials for glioblastoma patients. We developed a high-throughput assay using GSCs and immune cells to identify MHC I receptor-bound immunopeptides as response effectors utilizing 27 immune response markers-based flow cytometry. RESULTS GSCs (n=6), infected ex vivo with OV (after 12h at MOI=0.1), yielded EVs via ultracentrifugation. Global proteomic profiling mass spectrometry of EV detected 5,203 proteins, with TAP1, a pivotal player in loading viral peptide antigens onto MHC class I, as the most EV-enriched protein post-OV infection. MHC I was significantly enriched in EV, covering up to 0.1% of all EV proteins, allowing the detection of 2,276 MHC I-bound immunopeptides (out of a total of 45,963 peptides detected). Functional analysis of EVs’ immunological properties via ex vivo PBMC activation assays revealed OV-deregulated EV secretome, with upregulated proteins associated with immune response activation leading to increased activity of NK cells, DCs, NKTs, and CD8+ T cells subpopulations. The effect was diminished by MHC I antibody neutralization. CONCLUSIONS Designed a high-throughput immune phenotype assay, employing a training cohort of GSCs and immune cells as donors and recipients, respectively, pinpointed MHC I receptor-bound immunopeptides and TAP1 overexpressed in response to OV infection as mechanistic effectors of the immune response. Methodological innovation of zooming on EV fraction instead of whole cell material allowed us to bypass the limitations of antigen and patient material scarcity by offering a higher MHC I presenting surface in the material devoid of bulky cellular protein complexes. EV-MHC immunoprecipitation proteomic approach thus correlates personalized clinical interventions with prognostic therapy-outcome assays, stratifying patients for new immunotherapeutic regimens. Supported by National Science Centre Poland grants: 2021/41/N/NZ6/02682 (K.K.), 2022/45/B/NZ5/04226 (A.B.), 2020/39/B/NZ5/02893, 2021/41/B/NZ6/02436 (J.G.), and the National Agency for Academic Exchange grant: PPN/PPO/2019/1/00001 (J.G.).