tbuckley/cabot-search huggingface dataset:
P26.12.A REPURPOSING ITRACONAZOLE AND PYRIMETHAMINE WITH TEMOZOLOMIDE AS A COMBINATORIAL TREATMENT FOR GLIOBLASTOMA
Authors: T Lootens, J Vandersteene, H Pinson, T Boterberg, V Vermeirssen, O De Wever, F De Smet, R Raedt
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Glioblastoma (GB) is marked by a poor median overall survival of 14-16 months despite surgery, radiotherapy and chemotherapy, highlighting the need for improving treatment. Drug repurposing offers the advantage of using commercially available compounds with known safety profiles, while simultaneously addressing the need for more effective and cost-efficient cancer treatments. However, preclinical or clinical evidence of efficacy is often lacking or merely anecdotal. In this in vitro study, we evaluated the therapeutic potential of combining repurposed agents itraconazole (ITR) and pyrimethamine (PYR) with low-dose temozolomide (TMZ) using primary GB patient-derived stem cell lines (PDSCLs). MATERIAL AND METHODS CellTiter-Glo cell viability assays were used to assess the effects of single and combination drug treatments in PDSCLs from both primary and recurrent GB. Staining with propidium iodide followed by flow cytometry was performed to investigate changes in cell cycle stages. Western blot and qPCR analysis to confirm the mode of action are ongoing. RESULTS Both ITR and PYR, at concentrations within the clinical plasma range, caused marked reductions in cell viability after 120h in a heterogeneous population of eight PDSCLs. Variable response rates were observed between cell lines with lowest IC50 values of 0.5 µM and 2.2 µM for ITR and PYR, respectively. Synergy analysis revealed mainly additive effects between the two drugs (Bliss scores of -4.93, 0.15, 1.79, 1.86, 4.19 and 7.67 in six PDSCLs). These effects were accompanied by an increased fraction of cells in the G1 phase after combinatorial treatment with ITR and PYR. Lastly, combining TMZ with this repurposed combination led to a significant decrease in cell viability across five PDSCLs after nine days of treatment, compared to TMZ monotherapy. CONCLUSION Our data shows that combining ITR and PYR with TMZ induces strong anti-cancer effects in PDSCLs, highlighting its potential as a combinatorial treatment for glioblastoma. In vivo validation and mode of action studies are currently ongoing. [This work was funded by a fellowship grant from “Fonds voor Wetenschappelijk Onderzoek” (FWO), grant number 1SH3H24N, and a project grant from the “Cancer Research Institute Ghent” (CRIG).]
P26.14.B VITAMIN D3 ENHANCES TEMOZOLOMIDE EFFICACY IN GLIOBLASTOMA CELLS WHILE PROTECTING NORMAL ASTROCYTES: INVESTIGATING THE EFFECTS OF ADJUNCTIVE THERAPY
Authors: M Morelli, F Di Lorenzo, F Nannipieri, S Trasciatti, A Di Stefano, F Lessi, C Mazzanti
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Glioblastoma (GB), the most aggressive brain tumor, poses challenges due to resistance to temozolomide (TMZ) and radiotherapy. Regorafenib (REGO) is used as second-line treatment for recurrences. Recent studies suggest potential benefits of using vitamin D, particularly cholecalciferol (VitD3), as adjunctive therapy in GB treatment, showing anti-proliferative effects and enhanced drug effectiveness. However, differences in the mechanisms of action between VitD3 and its active form, 1,25(OH)D3, require further investigation. MATERIAL AND METHODS Three commercial GB cell lines (U118, T98G, U87), and normal Human Brain Astrocytes (HBA) were treated for 48 hours with VitD3 and 1,25(OH)D3 at concentrations of 0, 3, 30, and 300 µM, and 0, 1, 10, and 100 nM, respectively along with TMZ and REGO at concentrations of 0, 10, 100, and 500 µM, and 0, 10, 20, 50 µM, respectively. Additionally, REGO with or without VitD3 was tested on tissue-derived primary cell cultures. Cellular responses to treatments in terms of cell proliferation were assessed using WST-1 and Crystal Violet assays. RESULTS VitD3 significantly reduced cell viability and proliferation in commercial tumor cell lines but not in healthy cell lines. Moreover, treatment with 10 and 100 µM of TMZ along with VitD3 resulted in an additional decrease in cell proliferation in commercial cell lines but not in healthy HBA. Conversely, REGO treatment did not further reduce proliferation with increasing VitD3 concentrations in tumor cell lines, HBA, or primary cultures. It is noteworthy that primary cultures exhibited greater resistance to REGO and/or VitD3 treatment compared to commercial cell lines. At all tested concentrations, 1,25(OH)D3 did not significantly reduce proliferation, either alone or with TMZ. CONCLUSION VitD3 unexpectedly enhances TMZ toxicity in tumor cell lines and may have a protective effect on healthy astrocytes in the presence of TMZ, suggesting potential as adjunctive therapy with existing TMZ chemotherapy, pending further understanding of the underlying molecular mechanisms. The efficacy of its active form requires testing at higher concentrations.
P13.10.A NORADRENERGIC AGONISTS AS NEW TREATMENT OPPORTUNITY AGAINST RADIATION-INDUCED COGNITIVE DECLINE
Authors: I De Bie, L Berden, B Peeters, C Vanhove, T Boterberg, K Tabury, I Primac, R Raedt, R Benotmane
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Pediatric patients undergoing cranial irradiation are at risk of developing neurocognitive impairments. Mechanistically, radiation-induced injury to the hippocampi could play an important role in this debilitating condition, by inducing loss of neural stem/progenitor cells (NSCs/NPCs) and neuroinflammation, eventually leading to hippocampal atrophy. Noradrenergic (NA) agonists can potentially mitigate this radiation-induced cognitive decline by reducing cell death and inflammation. Therefore, we hypothesize that pharmacological boosting of NA will attenuate radiation-induced impairments in neurogenesis and decrease neuroinflammation, resulting in decreased memory dysfunction. MATERIAL AND METHODS Mice were irradiated with a single fraction of 10 Gy at P22. Reboxetine and Atipamezole were administered as 7 daily intraperitoneal injections, starting immediately after radiation. Sham therapy was administered in an identical manner by injecting equivalent volumes of sterile 0.9% NaCl. At 6 hours, 1 week, and 1 month post-radiation, radiation-induced NSCs/NPCs death, deficits in neurogenesis, and inflammation were investigated with histology. Additionally, at 1 month post-irradiation, hippocampal atrophy and memory deficits were investigated by ex-vivo MRI and a behavioral test battery, respectively. RESULTS We report that Reboxetine and Atipamezole significantly mitigate radiation-induced toxicity in the hippocampi. At 6 hours post-irradiation, NA agonists reduce radiation-induced apoptosis and microglial inflammation compared to sham treatment. A substantial reduction in the number of NSCs/NPCs and immature neurons within the hippocampal dentate gyrus was observed at both 1 week and 1 month post-irradiation. This deleterious effect of irradiation on neurogenesis was significantly attenuated by Reboxetine and Atipamezole, at both timepoints. Considerable hippocampal volume loss was observed after radiotherapy, which was prevented by both drugs. Finally, behavioral testing revealed that treatment with Reboxetine after radiotherapy successfully mitigated radiation-induced deficits in working and reference memory. CONCLUSION The present findings document the marked benefits of NA treatment against radiation-induced hippocampal NSCs/NPCs death, impaired hippocampal neurogenesis, neuroinflammation, and hippocampal atrophy. Additionally, we demonstrate that Reboxetine is able to mitigate radiation-induced memory dysfunction, which highlights the potential of NA treatment for resolving long-standing complications faced by pediatric brain tumor survivors. This project is supported by BOF (Bijzonder Onderzoeksfonds) - Ghent University (I. De Bie is a PhD fellow, grant number 01D07923).
P27.02.A ANTI-EPILEPTIC WITHDRAWAL IN GLIOMAS: A RETROSPECTIVE STUDY IN A SINGLE SCOTTISH TERTIARY CENTRE
Authors: F Merchant, E Molinari
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Seizures are common in brain tumours (BTs). With no fixed guidelines to guide anti-epileptics (AEDs) discontinuation in BTs, we evaluated factors influencing the decision to discontinue AEDs and its outcome. MATERIAL AND METHODS Retrospective study on single regional centre for neuro-oncological service from April 2018 to April 2023. Eligible BT patients were seizure free ≥ 1 year post surgery, had histologically confirmed gliomas (WHO grade I-IV) and underwent gross total resection. We analysed separately patients who were weaned after being started on AEDs prophylactically. Primary outcomes were: (1) shared decision-making outcome and (2) seizure recurrence. Data analysed included tumour characteristics, antitumour treatments and seizure freedom. RESULTS Over 2020-2023, 30/240 patients (13%) met the selection criteria for AED withdrawal and 22/30 (73%) were agreeable to AEDs withdrawal. 9/22 (41%) of those who withdrew AEDs had seizure recurrence, with 6/9 (67%) having a seizure within 6 months following withdrawal. 5/9 (55%) had tumour progression within 3-6 months of having a seizure. None of those who remained on AEDs had seizure recurrence.A shorter BT related epilepsy (BTRE) duration (p&amp;lt;0.01) and radiotherapy treatment (p&amp;lt;0.05) resulted in decreased seizure recurrence following withdrawal. Most patients were on Levetiracetam monotherapy and our data did not allow comparison with other AEDs. CONCLUSION In 73% of patients, a shared decision process led to AEDs withdrawal, with 59% remaining seizure free. Lower recurrence risk was linked to shorter BTRE duration and radiotherapy. Further studies are required to better stratify patients at higher risk of seizure recurrence.
P13.14.A REPEATED TREATMENT-ASSOCIATED CHANGES IN PATIENTS WITH A DIFFUSE GLIOMA
Authors: A Mechroubi, C M Flies, J W Dankbaar, J J C Verhoeff, P A Robe, T J Snijders
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Radiological and clinical progression after treatment of patients with a diffuse glioma can be caused by progressive disease (PD) or be an effect of treatment-associated changes/pseudoprogression. These changes may occur more than once in the same patient, but data on such repeated changes are scarce. The goal of this study is to investigate the incidence of repeated treatment-associated changes, as well as the associated clinical and radiological characteristics. MATERIAL AND METHODS In this retrospective mono-centre cohort study, patients with a diffuse glioma (WHO grade 2-4) who were treated with (chemo-)radiation and who developed treatment-associated changes afterwards were included. We reviewed the patient files to identify patients with more than 1 episode of treatment-associated changes. An episode of treatment-associated changes was defined either radiologically, as new or increasing contrast-enhancement (CE) on MRI that subsequently stabilised for ≥12 weeks or regressed for ≥1 month, or histologically, as treatment-associated changes without proliferating tumour. We searched for predictors for repeated treatment-associated changes with univariable odds ratios (OR) and compared the survival between patients with a single versus repeated episodes of treatment-associated changes. RESULTS Of 176 patients with treatment-associated changes, 58 patients (33%) developed 174 repeated episodes, of which 21% were confirmed by histopathology. Most patients (54%) had an IDH-wildtype glioblastoma. The first episode started one month after radiotherapy (median; interquartile range IQR, 0-11). The median duration of the radiological episodes was 32 weeks (IQR, 24.5-60). An oligodendroglioma grade 3 tumour type and an IDH-mutation compared to IDH-wildtype glioblastomas were positive predictors for repeated treatment-associated changes (OR, 8.8 and 5.0; both p, &amp;lt;0.001; 95%-CI, 2.1-37.1 and 2.2-11.6). Furthermore, a higher age was a protector against repeated treatment-associated changes (OR, 0.97; p, 0.018; 95%-CI, 0.94-0.99). MGMT promoter methylation or treatment characteristics (temozolomide, extent of resection, radiation dose) had no predictive value. Survival was longer in patients with repeated episodes compared to patients with one episode. Most of the patients had two to three episodes (N=48), but four to seven were also reported (N=10). CONCLUSION Repeated treatment-associated changes are common in patients with a diffuse glioma after a first confirmed episode, and are associated with prolonged survival. If there is a new or increasing CE lesion seen on the MRI of a patient after a previous episode of treatment-associated changes, physicians should consider the possibility of repeated treatment-associated changes. SUPPORT The foundations Stophersenkanker.nu and Vrienden UMC Utrecht supported this study.
P10.14.A DISTINCTION OF RADIONECROSIS AND TUMOR RECURRENCE BASED ON ANATOMICAL MRI COMPUTATIONAL ANALYSIS: A PROOF-OF-CONCEPT
Authors: M Mastilovic, K Sambourg, V Lebon, J Boban, M Edjlali, C Robert
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Most common malignant brain tumors are metastases (BM) and glioblastoma (GBM). Stereotactic and fractionated radiotherapy are modalities of choice for treatment of these malignancies. As a delayed complication of these treatments, radiation necrosis can occur several months and even years after the completion of radiotherapy. Distinguishing between tumor recurrence and radionecrosis solely through conventional MRI and functional MRI can be challenging at times. This challenge can result in delays in clinical decision-making or require utilization of additional imaging modalities such as PET for more accurate diagnosis. The aim of this study was to distinguish radionecrosis from tumor progression of post-radiotherapy brain tumors (BM and GBM) thanks to computer analysis comparing follow-up MRI exam to initial MRI exam, with DOPA PET as a gold standard. Developed method is a classification task at the patient level. MATERIAL AND METHODS This retrospective study included 16 patients with GBM and BM, whom had total of 17 lesions. Lesions were split into 3 subsets: 5 lesions of radionecrosis, 10 lesions of tumor progression, 2 lesions with mixed radionecrosis and progression. We analyzed 2 time points: baseline M0 exam - the first time showing enhancing part of the lesion on a post-radiotherapy MRI exam; follow-up M1 exam - MR time point exam on which the lesion clearly showed expansion. DOPA PET MRI was done at the time of M1 exam and served as a gold standard. Specific preprocessing steps were implemented. Firstly, automatic lesion segmentation and elastic co-registration were done, where M2 was aligned to M1 images. Then, rigid co-registration of M2 and DOPA was applied to the M1 images, after which center of the lesion was computed. The analysis of deformation vector field was performed. On the slice showing the maximum area of the lesion, the radius (mm) from the centre of mass of the lesion mask for M0 and M1 was calculated, and the absolute and relative variations for each 360º angle between M0 and M1 were studied and compared with the mean DOPA uptake per angle (Bq/ml). RESULTS Tumor recurrence and radionecrosis can be distinguished thanks to their growth patterns. The mean standard deviation on angular variation showed lower values for radionecrosis (4.69, IQR 3.37 - 4.49) compared to tumor progression (11.72, IQR 6.3 - 13.54), which goes in concordance with DOPA uptake on PET exam: lower in radionecrosis (4459.43 IQR 4466.55 - 4804.67) compared to progression (6099.02, IQR 4559.19 - 7328.72). CONCLUSION This fully-automatable proof-of-concept computational model showed that application of auto-segmentation and elastic co-registration in the analysis of tumor’s growth could have with certainty distinguish radionecrosis from tumor progression thanks to the analysis of their growth by obtained deformation vector fields. Further validation on bigger number of lesions is needed.
P13.09.B INVESTIGATING THE EFFECTS OF RADIATION FRACTION DOSES ON THE MOLECULAR BARRIER PERMEABILITY OF AN IN VITRO BLOOD-BRAIN BARRIER MODEL
Authors: M Ozturk, F Caglar, M KOYLU, S KAMER
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Brain tumors and metastases are major causes of death. The blood-brain barrier (BBB) makes it difficult to treat these conditions as it prevents drugs from reaching the tumor. We aim to evaluate the BBB’s permeability changes caused by varying radiotherapy doses. This will help develop treatment strategies that can benefit from this impaired function. MATERIAL AND METHODS We used an in vitro model of BBB by seeding cells in a 24-well plate with a porous membrane-separated insert. Human umbilical vein endothelial cells (HUVEC) and human astrocyte cells (NHA) were used for seeding. Transendothelial electrical resistance (TEER) measurements verified the accuracy of the model. A device developed by the Department of Physics was used for TEER measurement. Radiation was delivered in single fractions of 2, 4, 6, 8, 16, and 25 Gy. After ionizing radiation, the cells were incubated with the TEER device for 72 hours, with measurements taken every two hours. In addition, glioblastoma (GBM) cell lines were seeded at the bottom of the 24-well plate where the insert was placed to assess drug dose efficiency, which can vary according to membrane permeability. Two different drugs were applied to the irradiated BBB model. Membrane permeability was determined by ELISA, MTT proliferation assay, and cell wound healing assay. RESULTS There was a significant decrease in TEER values in all dose groups after irradiation compared to the control group (p&amp;lt;0.001). No significant difference was found when fraction doses were evaluated (p=0.639). The most significant dose-independent decrease occurred between hours 2 and 6. It was noted that the change in the rate of resistance decline increased in direct proportion to the dose. Temozolomide (TMZ), used to evaluate the proliferation of GBM cell lines seeded on the bottom after irradiation, was effective on GBM cell proliferation, and the lowest dose for effective permeability was 4 Gy. In the cell wound healing experiment performed as an indicator of repopulation and repair capacity, it was observed that while bridging started in the early hours after irradiation in the TMZ-treated groups at low fraction doses, there was no wound closure at the end of 72 hours at high fraction doses. When the results of ELISA measurements made after the application of trastuzumab (TRAS), which is 750 times larger than TMZ, were evaluated, TRAS levels below 500 ng/ml were found at doses of 2, 4, and 6 Gy. TRAS levels of 1500 ng/ml were measured at doses of 8, 16, and 25 Gy. CONCLUSION Our study demonstrates that different doses of ionizing radiation combined with chemotherapy may increase tumor access to therapeutic agents and evaluates the time course of this relationship. We conclude that permeability through the BBB is related to molecular weight, which increases proportionally with increasing dose fraction.
P16.10.A UNRAVELING THE CLINICAL IMPLICATIONS OF TRIM24::NTRK2 FUSION GENE IN PEDIATRIC HIGH-GRADE GLIOMA: A CASE STUDY
Authors: I Karlsson, S Keane, L Deland, A Lindlöf, T Kling, T Olsson Bontell, H Fagman, J Nilsson, D Nilsson, M Sabel, H Carén, F Abel
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND High-grade gliomas are among the deadliest of all childhood cancers and the leading cause of cancer-related mortality in children. The standard treatment is resection followed by chemotherapy, most often temozolomide and radiation therapy. Unfortunately, there is no evidence that temozolomide influences survival in pediatric patients and only a limited number of new drugs have been identified for specific subgroups of tumors. The identification of fusion genes as possible drivers of the disease offers an opportunity for targeted therapies. We present a case of a six-year-old patient with a novel TRIM24::NTRK2 fusion positive epithelioid glioblastoma with subsequent relapses. METHODS We investigated the ramification of this fusion and evolution of the tumor through whole genome sequencing, RNA-sequencing and DNA methylation profiling, and studied the effect of the patient’s treatment using patient-derived cell cultures. RESULTS Our studies show that the TRIM24::NTRK2 fusion has oncogenic abilities but loses its importance as the tumor evolves. In addition, we demonstrate an increased drug resistance over time, further indicating the diminished driver function of the fusion. CONCLUSION The use of resequencing revealed parallel development of tumor subclones with different genomic alterations, highlighting the importance of genomic profiling from various parts of the tumor. FUNDING This work was supported by the Swedish Research Council, the Swedish Childhood Cancer Foundation, and the Swedish Cancer Society
P09.03.B ASSESSMENT OF RESPONSE TO LOMUSTINE-TEMOZOLOMIDE CHEMOTHERAPY IN ADDITION TO RADIOTHERAPY IN PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA USING FET PET
Authors: J Werner, M M Wollring, C Tscherpel, E K Rosen, G Ceccon, I Stetter, P Lohmann, J Weller, G Stoffels, C Baues, E Celik, F M Mottaghy, R Goldbrunner, U Herrlinger, G R Fink, K Langen, N Galldiks
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND We examined the value of O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET for early response assessment in patients with newly diagnosed glioblastoma and methylated O6-methylguanine-DNA methyltransferase promoter treated with lomustine-temozolomide chemotherapy in addition to radiotherapy. MATERIAL AND METHODS Thirty-one patients (29-74 years) were treated according to the CeTeG/NOA-09 phase-3 trial. FET PET and anatomical MRI were performed at baseline and follow-up after the third cycle. We obtained mean and maximum tumor-to-brain ratios (TBR) and metabolic tumor volumes (MTV). Thresholds derived from FET PET were defined using receiver operating characteristic analyses to predict progression-free survival (PFS) of ≥12 months. The predictive value of FET PET parameters was subsequently evaluated using univariate and multivariate survival estimates. MRI response assessment was based on the RANO 1.0 criteria. FET PET data were also used to estimate response according to the PET RANO 1.0 criteria. RESULTS Patients received a median number of 6 cycles of lomustine-temozolomide chemotherapy (3-6 cycles). After treatment initiation, the median follow-up was 17.2 months (7.2-59.4 months). As of April 2024, we confirmed tumor progression according to the RANO 1.0 criteria in 24 patients (77%). After three cycles of lomustine-temozolomide chemotherapy, a reduced mean TBR value by ≥10% predicted a significantly longer PFS (31.0 vs. 10.4 months; P=0.039). In contrast, changes in maximum TBR values, MTV, the RANO 1.0 criteria, and the PET RANO 1.0 criteria were not predictive for response (P&amp;gt;0.05). Multivariate survival analysis revealed that changes in mean TBR values predicted a significantly prolonged PFS independent of age, the extent of resection, and the Karnofsky Performance Status (P=0.036; HR, 3.892; 95% CI, 1.242-17.230). CONCLUSION Our results suggest that FET PET is clinically valuable for identifying responders to lomustine-temozolomide chemotherapy in addition to radiotherapy early after treatment initiation. The evaluation of FET PET’s value in predicting a significantly longer overall survival is ongoing.