bluuebunny/crossref_metadata_2025_split huggingface dataset:
OS05.5.A Methylation analysis of matched primary and recurrent IDHmt astrocytoma; an update from the Glioma Longitudinal Analysis NL (GLASS-NL) consortium
Authors: Vallentgoed W R , Niers J M , van den Bent M J , Kouwenhoven M C M , Kros J M , Martin I , van Thuijl H F , van de Wiel M A , Wesseling P , French P J 
Published: September 2021

Abstract

BACKGROUND
The evolutionary processes that drive progression in patients with IDH-mutant astrocytoma remain unclear. The GLASS-NL consortium, as part of the larger worldwide GLASS consortium, was initiated to gain insight into the molecular mechanisms underlying glioma evolution and to identify markers of progression in IDH-mutant astrocytomas. Such markers can ultimately assist clinical decision making. Here, we present the first results of genome wide methylation profiling of samples included in the GLASS-NL study.

MATERIAL AND METHODS
110 adult patients were identified with an IDH-mutant astrocytoma at first diagnosis. All patients underwent a surgical resection of the tumor at least twice, separated by at least 6 months with a median of 40.9 months (IQR: 24.0, 64.7), in 37% and 18% of the cases, patients were treated with radiotherapy or chemotherapy respectively, before surgical resection of the recurrent tumor. Methylation profiling was done on (macro dissected) DNA isolated of 235 samples from 103 patients (102 1st, 101 2nd, 29 3rd, and 3 4th resection), using the Infinium MethylationEPIC BeadChip array. Copy number variations were also derived from these data. Methylation classes were determined according to Capper et al. (2018). Overall survival (OS) was measured from date of first surgery.

RESULTS
Of all primary tumors, the methylation-classifier assigned 85 (87%) to the A_IDH (‘low grade’) subclass and 10 (10%) to the A_IDH_HG (‘high grade’) subclass. The relative proportion of high grade tumors increased ~three-fold at tumor recurrence (32/101, 32%) and even further in the second recurrence (15/29, 52%). The overall DNA-methylation levels of recurrent samples was lower than that of primary samples. This difference is explained by the increased number of high grade samples at recurrence, since near identical DNA-methylation levels were observed in samples that remained low grade. In an unsupervised analysis, methylation data derived from first and second resections of individual patients mostly (79%) cluster together. This indicates that variability between tumors is larger than temporal heterogeneity within tumors. Recurrent samples that do not cluster with their primary tumor, form a separate cluster and have relatively low genome-wide DNA-methylation.

CONCLUSION
Our data demonstrate that methylation profiling identifies a shift towards a higher grade at tumor progression coinciding with reduced genome-wide DNA-methylation levels.
OS06.2A Local immunotherapy of glioblastoma via AAV-mediated gene transfer of checkpoint inhibitors in combination with CAR-NK cells
Authors: Strecker M I , Wlotzka K , Strassheimer F , Reul J , Harter P N , Tonn T , Steinbach J P , Wels W S , Buchholz C J , Burger M C 
Published: September 2021

Abstract

BACKGROUND
Glioblastoma (GB) is the most common primary brain tumor which is characterized by low immunogenicity of tumor cells and prevalent immunosuppression in the tumor microenvironment (TME). Since expression of PD-L1 on GB cells has been described, immunotherapy with checkpoint inhibitors (CIs) may be a promising approach for GB treatment. However, systemic administration of CIs bears the risk of autoimmune-like side effects, while the intratumoral drug concentration reached may not be sufficient.

METHODS
We studied delivery of CIs through targeted Adeno-associated viral vectors (AAVs) encoding an anti PD-1 immunoadhesin (aPD-1) as a novel approach towards local immunotherapy in the syngeneic GL261-HER2 glioma model. Tumor cell-specific delivery was achieved by targeting HER2 via a specific designed ankyrin repeat protein (DARPin). We investigated the effects of this strategy alone and in combination with local injection of HER2-specific CAR-NK cells (NK-92/5.28.z), which have already shown efficacy in preclinical GB models and are currently under investigation in the CAR2BRAIN phase I clinical trial. Furthermore, aPD-1 functionality and cellular response to viral transduction as well as compatibility of both therapy approaches has been evaluated in various in vitro models.

RESULTS
HER2-AAV transduction efficacy of GB cells correlated with HER2 expression level, while target cells did not show anti-viral responses upon transduction. After transduction with aPD-1 HER2-AAVs, aPD-1 immunoadhesin was secreted in a time-dependent manner, bound its target on PD-1-expressing cells and was able to re-activate T-cells due to PD-1 blockade. AAV-transduction did not interfere with CAR-NK cell mediated tumor cell lysis. Biodistribution studies in mice revealed the presence of aPD-1 up to 10 days after a single HER2-AAV injection. In subcutaneous GL261-HER2 tumors, local treatment with HER2-AAVaPD-1 or HER2-AAVIgG-Fc+ NK-92/5.28.z therapy had no significant effect, whereas combination therapy profoundly delayed tumor growth.

CONCLUSIONS
Local therapy with aPD-1 encoding HER2-AAVs in combination with NK-92/5.28.z cells is a promising novel strategy for GB immunotherapy with the potential to enhance efficacy and reduce side effects.
OS06.3A LSD1-directed therapy curtails glioblastoma tumorigenicity by limiting the adaptation of tumor initiating cells to stressful environments
Authors: Faletti S , Osti D , Ceccacci E , Richichi C , Costanza B , Marotta G , Corà D , Pelicci G 
Published: September 2021

Abstract

BACKGROUND
Glioblastoma (GBM) is a fatal tumor whose aggressiveness, heterogeneity, therapy resistance and poor blood-brain-barrier penetration hinder the amelioration of the standard-of-care. Included in the GBM mass are the tumor initiating cells (TICs), representing the driver of GBM growth and relapse in virtue of their stem-like traits and therapy-resistance. Being constantly exposed to environmental stress, including nutrients deficiency, hypoxia and therapeutic insults, all GBM cells -and TICs in particular- have to be highly adaptive in order to survive. Thus, their ability to cope with stress could be targeted to curtail TICs maintenance and the whole GBM aggressiveness. The key of TICs adaptation relies, among the others, on their epigenetic plasticity, hence encouraging epigenetic drugs testing.

MATERIAL AND METHODS
By exploiting patient-derived GBM TICs and orthotopic xenograft models, we tested the antitumorigenic features of a novel, selective, orally bioavailable and brain-penetrant Lysine-specific histone demethylase 1 inhibitor (LSD1i). We confirmed the specificity of its effects by LSD1 genetic targeting. A combination of RNA-seq, Chromatin Immunoprecipitation(ChIP)-seq, Mass Spectrometry and reverse genetic experiments unraveled LSD1 molecular players in GBM TICs.

RESULTS
We identified LSD1 as a druggable target in human GBM: LSD1i treatment, mirrored by LSD1 genetic targeting, impairs growth, viability, stem-like traits and in vivo tumorigenicity of GBM TICs. Mechanistically, LSD1 is crucial for the expression of the activating transcription factor 4 (ATF4), which coordinates the integrated stress response (ISR) to manage stressful stimuli as nutrient deprivation and endoplasmic reticulum stress. By mimicking these stress cues in vitro, we found that LSD1i triggers a delayed but unabated ATF4 translation which provokes an over-lasting ISR, eventually culminating in GBM TICs apoptosis. Lastly, LSD1 demethylase activity is dispensable for ATF4 induction. Rather, LSD1i exerts its anti-tumorigenic potential by interfering with LSD1 scaffolding function in GBM TICs.

CONCLUSION
LSD1-directed therapy is likely a promising strategy to hinder GBM. By sensitizing GBM TICs to stress, LSD1i endangers the GBM TICs pool. The effectiveness of LSD1i administration in different patient-derived GBM TICs and xenografts, regardless of their molecular profile, places a strong rationale toward the clinical translation of this approach for GBM management.

FUNDING
Italian association for Cancer Research (AIRC) and Italian Ministry of Health
OS08.6.A Glioblastoma treatment response machine learning monitoring biomarkers: a systematic review and meta-analysis
Authors: Booth T C , Chelliah A , Roman A , Al Busaidi A , Shuaib H , Luis A , Mirchandani A , Alparslan B , Mansoor N , Ashkan K , Ourselin S , Modat M , Grzeda M 
Published: September 2021

Abstract

BACKGROUND
The aim of the systematic review was to assess recently published studies on diagnostic test accuracy of glioblastoma treatment response monitoring biomarkers in adults, developed through machine learning (ML).

MATERIAL AND METHODS
PRISMA methodology was followed. Articles published 09/2018-01/2021 (since previous reviews) were searched for using MEDLINE, EMBASE, and the Cochrane Register by two reviewers independently. Included study participants were adult patients with high grade glioma who had undergone standard treatment (maximal resection, radiotherapy with concomitant and adjuvant temozolomide) and subsequently underwent follow-up imaging to determine treatment response status (specifically, distinguishing progression/recurrence from progression/recurrence mimics - the target condition). Risk of bias and applicability was assessed with QUADAS 2. A third reviewer arbitrated any discrepancy. Contingency tables were created for hold-out test sets and recall, specificity, precision, F1-score, balanced accuracy calculated. A meta-analysis was performed using a bivariate model for recall, false positive rate and area-under the receiver operator characteristic curve (AUC).

RESULTS
Eighteen studies were included with 1335 patients in training sets and 384 in test sets. To determine whether there was progression or a mimic, the reference standard combination of follow-up imaging and histopathology at re-operation was applied in 67% (13/18) of studies. The small numbers of patient included in studies, the high risk of bias and concerns of applicability in the study designs (particularly in relation to the reference standard and patient selection due to confounding), and the low level of evidence, suggest that limited conclusions can be drawn from the data. Ten studies (10/18, 56%) had internal or external hold-out test set data that could be included in a meta-analysis of monitoring biomarker studies. The pooled sensitivity was 0.77 (0.65–0.86). The pooled false positive rate (1-specificity) was 0.35 (0.25–0.47). The summary point estimate for the AUC was 0.77.

CONCLUSION
There is likely good diagnostic performance of machine learning models that use MRI features to distinguish between progression and mimics. The diagnostic performance of ML using implicit features did not appear to be superior to ML using explicit features. There are a range of ML-based solutions poised to become treatment response monitoring biomarkers for glioblastoma. To achieve this, the development and validation of ML models require large, well-annotated datasets where the potential for confounding in the study design has been carefully considered. Therefore, multidisciplinary efforts and multicentre collaborations are necessary.
OS10.5.A BrainWear: Longitudinal, objective assessment of physical activity in 42 HGG patients
Authors: Dadhania S , Pakzad-Shahabi L , Mistry S , Le-Calvez K , Saleem W , Mohammed W , Williams M 
Published: September 2021

Abstract

BACKGROUND
In patients with High Grade Glioma (HGG), QoL and physical function decline with progressive disease (PD). Objective assessment of physical functioning is challenging as patients spend most of their time away from the hospital. Wearable technology allows measurement of objective, continuous activity data in a non-obtrusive manner. BrainWear is a phase II feasibility study, collecting longitudinal physical activity (PA) data from patients with primary and secondary brain tumours.

MATERIAL AND METHODS
All agreed to wear an Axivity AX3 triaxial accelerometer and completed the EORTC QLQ C30 and BN20, the Montreal Cognitive Assessment (MoCA) and Multidimensional fatigue inventory (MFI) questionnaires. Accelerometers were changed at 14-day intervals, and PRO questionnaires completed at pre-specified study intervals. Age-sex matched controls were identified from the UK Biobank 7-day accelerometer study. Raw accelerometer data was processed using UK Biobank accelerometer software and inclusion of high-quality wear time selected as ≥72 hours of data in a 7-day data collection and data in each 1-hour period of a 24-hour cycle over multiple days. We analysed variation in activity by patient demographics and treatment days. The wilcoxin-signed rank test was used to compare participant activity between radiotherapy treatment days and non-treatment days, mixed effects models were used to evaluate longitudinal changes in activity and we used k-means clustering to characterise clusters of PA behaviours.

RESULTS
We have collected 3458 days of accelerometer data from 42 HGG patients with a median age of 59, 80% of which has been classified as high quality. Patients &gt;60 years spend more time doing moderate activity compared to those &lt;60 years (52 vs 33 minutes/day, p=0.012), and there are significant differences in mean vector magnitude (17.12 vs 16.85 mg, p=0.013) and walking (91 vs 72 minutes/day) between radiotherapy and non-radiotherapy days. In patients having a 6-week RT course, time spent in daily moderate activity falls 4-fold between week 1 and the second week after RT completion (70 minutes to 16 minutes/day). Comparing HGG patients to healthy controls shows a significant difference in time spent across all activities (p&lt;0.05). K-means clustering analysis shows three distinct clusters, with 87% of HGG patients falling into the very inactive or moderately active groups.

CONCLUSION
Digital remote health monitoring is feasible and acceptable with 80% of data classified as high-quality wear-time suggesting good patient adherence. Triaxial accelerometer data collection captures objective evidence of a significant reduction in moderate daily activity at the time of expected peak RT side-effects and patients walk almost 30% less on non-RT treatment days. HGG patients show significantly lower levels of activity compared to matched healthy controls.
OS10.7.A Localization patterns of language errors during direct electrical brain stimulation: a systematic review
Authors: Collée E , Vincent A , Dirven C , Satoer D 
Published: September 2021

Abstract

BACKGROUND
Awake craniotomy with direct electrical stimulation (DES) is the standard treatment for patients with eloquent area gliomas. Language errors (paraphasias) are detected with DES and they indicate functional boundaries that need to be maintained to preserve quality of life. However, it is not fully clear in which brain locations paraphasias at different linguistic modalities and levels (production, comprehension, reading, writing, phonology, semantics, syntax) occur.

MATERIALS AND METHODS
A systematic review was conducted. We included 102 studies reporting on specific paraphasias and the corresponding brain locations during awake craniotomy with DES in adult glioma patients.

RESULTS
First, a wide distribution of brain locations for all paraphasias (n=930) was found, but patterns were observed. Cortically, paraphasias occurred most often in the precentral gyrus (22%), while subcortically, they occurred mainly at the inferior fronto-occipital fascicle (IFOF: 10%). Localization patterns for different paraphasia types and the corresponding language functions were also found: production/articulation (n=393)-precentral gyrus (41%), inferior frontal gyrus (9%), frontal aslant/striatal tract (4%), postcentral gyrus (3%); semantics (n=128)-IFOF (57%), superior temporal gyrus (9%); phonology (n=115)-arcuate fascicle (52%), superior longitudinal fascicle (10%), uncinate fascicle (3%); reading (n=25)-temporal lobe (48%), inferior longitudinal fascicle (32%); syntax (n=15)-inferior frontal gyrus (27%); speech initiation (n=9)-supplementary motor area (33%), frontal aslant tract (22%), frontal striatal tract (22%); writing (n=7)-superior parietal gyrus (71%). Second, 59% of all paraphasias occurred cortically, 40% subcortically and 1% at both levels.

CONCLUSION
The localization of most paraphasias are consistent with the assumed functionality of those brain locations as presented in the Dutch Linguistic Intraoperative Protocol model. However, new locations for production/articulation, phonology, reading and writing were found. This needs to be taken into consideration for future selection of pre, intra and postoperative language tasks at different language modalities and levels. Additionally, DES should always be applied at the subcortical level as a standard addition to the routine cortical mapping during awake craniotomy. In conclusion, this is the first systematic review on the localization of specific paraphasias during awake craniotomy. Based on the identified language localization patterns, language tasks could be selected more accurately. This could guide, and perhaps improve, pre, intra and postoperative language testing and monitoring, which in turn, may pave the way to a better postoperative language outcome. The possible relation between different intraoperative paraphasias and language outcome has yet to be determined.
OS12.6.A Combination therapy of CAR-NK-cells and anti-PD-1 results in high efficacy against advanced-stage glioblastoma in a syngeneic mouse model and induces protective anti-tumor immunity in vivo
Authors: Strassheimer F , Strecker M I , Alekseeva T , Macas J , Demes M C , Mildenberger I C , Tonn T , Wild P J , Sevenich L , Reiss Y , Harter P N , Plate K H , Wels W S , Steinbach J P , Burger M C 
Published: September 2021

Abstract

INTRODUCTION
Checkpoint inhibitors as well as adoptive cell therapy hold promise for cancer therapy and encouraging treatment responses have already been demonstrated in different cancer indications. Glioblastoma (GB) is the most common and aggressive primary brain tumor. Standard therapy has very limited efficacy in the majority of patients. Analysis of the GB microenvironment (TME) has shown prominent immunosuppressive features, including expression of PD-L1 on tumor cells and increased frequency of FOXP3-positive regulatory T cells. While the surrounding brain is HER2-negative, GB are frequently HER2-positive, suggesting HER2 as a promising target for adoptive immunotherapy. Previous results from mouse glioma models showed efficacy of CAR-NK cells (NK-92/5.28.z) targeted against HER2 as monotherapy with early stage but not with advanced-stage tumors.

MATERIALS AND METHODS
The murine glioma cell line GL261 was transfected with human HER2. Tumor cells were implanted either subcutaneously or orthotopically into C57BL/6 mice and treated either with HER2-specific NK-92/5.28.z cells alone or in combination with an anti-PD-1 antibody. Effects on tumor growth and survival were determined. Lymphocyte infiltration and immunosuppressive TME were characterized via highplex multi-color flow cytometry (FACS Symphony) and IHC (Phenoptics). Furthermore, gene expression profiles of tumor-infiltrating cells were determined via bulk RNAseq (NanoString).

RESULTS
Combined treatment with NK-92/5.28.z cells and anti-PD-1 checkpoint blockade resulted in synergistic effects, with tumor regression and long-term survival observed even in advanced-stage tumor bearing mice. Analysis of the TME showed changes in lymphocyte infiltration and increased expression of exhaustion markers in tumor and immune upon combined treatment with NK-92/5.28.z cells and anti-PD-1 antibody resulting in an altered TME. Both, PD-1 and Lag-3 expression are highly upregulated on tumor infiltrating T cells. Total infiltrating lymphocytes show a rather cytotoxic phenotype up combination treatment with NK-92/5.28.z cells and anti-PD-1 antibody

CONCLUSION
Our data demonstrate that efficacy of NK-92/5.28.z cells can be enhanced by combination with checkpoint blockade, resulting in successful treatment of advanced tumors refractory to NK-92/5.28.z monotherapy. Furthermore, the combination therapy induced a cytotoxic rather than immunosuppressive TME, leading to a primed immune system. To translate the concept of CAR-NK-cell therapy plus checkpoint inhibition to a clinical setting, we are adding a combination therapy cohort to our ongoing phase I clinical study (CAR2BRAIN; NCT03383978).
OS13.3.A Establishment of a novel system to specifically trace and ablate quiescent/slow cycling cells in high-grade glioma
Authors: Antonica F , Santomaso L , Aiello G , Pernici D , Miele E , Tiberi L 
Published: September 2021

Abstract

BACKGROUND
High-grade gliomas are the most common malignant brain tumors, with poor prognosis due to recurrence and tumor infiltration after surgical removal and chemotherapy. Quiescent/slow cycling stem cells have been proposed to be one of the main players of tumor relapse but their involvement in in the infiltration remain unclear. Despite they have been described in mouse models or after transcriptional profiling of human tumor samples, their direct visualization, targeting and ablation remains a challenge.

MATERIAL AND METHODS
Tumors were induced over-expressing oncogenic forms of MET and p53 in the subventricular zone (SVZ) of P2 mouse brain as well as human forebrain organoids. The co-expression with specific cell cycle sensors as well as lineage specific CreERT2 under control of stem cells promoters allowed to visualize and target glioma stem cells.

RESULTS
Here, we used a fluorescent cell cycle sensor to visualize quiescent tumor cells in mouse brain cancer and human cancer organoids. In particular, we characterized them within the tumor revealing the invasiveness capacity of slow cycling tumor cells. Furthermore, we generated a new system to specifically trace and ablate such cells. Indeed, lineage tracing experiments allowed to trace quiescent Prom1 progeny in the tumors after temozolomide treatment. In addition, the selective ablation of qProm1 in mouse brain cancer reduced tumor infiltration. Finally, time-lapse experiments showed that slow cycling cells are also able to infiltrate co-cultured human brain cancer organoids.

CONCLUSION
Overall, our data show that quiescent/slow cycling cells are key driver of tumor invasiveness, the major malignant feature of high-grade brain cancer.