bluuebunny/crossref_metadata_2025_split huggingface dataset:
DIPG-25. RELATIONSHIP BETWEEN MOLECULAR CLASSIFICATION, ORIGIN AND PROGNOSIS IN DIFFUSE MALIGNANT GLIOMA IN CHILDREN
Authors: Kagawa Naoki , Nakagawa Tomoyoshi , Kuroda Hideki , Tachi Tetsuro , Hirayama Ryuichi , Kijima Noriyuki , Okita Yoshiko , Kishima Haruhiko 
Published: June 2024

Abstract

INTRODUCTION
Diffuse malignant gliomas that occurs in childhood is recognized as a biologically different disease from that in adults. Furthermore, with the recent development of molecular diagnostics, diffuse midline glioma (DMG), which occurs mainly in the thalamus and brainstem, frequently occurs in childhood and have poor prognosis. We report the relationship between imaging findings, origin, and prognosis of diffuse malignant glioma in children or young adult based on our case series.

PATIENTS AND METHODS
43 cases of malignant glioma that occurred from childhood to young adult (below 30 years old) and were treated at our hospital since 2004 were registered in the analysis. Of the 42 cases, 24 cases were in brain stem, 11 cases in cerebral hemisphere, 6 cases in thalamus, and 1 case in cerebellar hemisphere. Histological diagnosis was possible in 31 cases, but without histological verification in 11 brain stem lesions. Histological diagnosis included 13 high-grade glioma (GBM, including NOS and G34R mutations), 11 DMG, and 7 anaplastic astrocytoma.

RESULTS
Of 13 cases of hemispheric high-grade gliomas, 2 cases had long-term survival (both cases received WT1 peptide vaccination), and 1 case survived for more than 5 years (total resection, MGMT methylation). Among the DMGs, 7 cases were found in brain stem (5 pons, 2 pontomedullary junction, 1 cerebellar peduncle, and 1 midbrain), 3 cases in the thalamus. Two cases of onset at the pontomedullary junction were found incidentally, and the symptoms gradually increased during follow-up, and multidisciplinary treatment was performed. Bilateral thalamus DMG with HIST1H3B mutation showed slowly growing and invasion.

SUMMARY
There were cases of pediatric hemisphere glioblastoma with long-term survival. In addition, the origin and imaging findings of DMG were various, and tumors that originate at the pontomedullary junction may be relatively favorable.
DIPG-27. MATCHED PRIMARY-RELAPSE PEDHGG PATIENT-DERIVED XENOGRAFT MODELS TO IDENTIFY THERAPY RESISTANCE PROFILES
Authors: Barnerjee Srijita , Zhao Miao , Rosen Gabriela , Olsen Thale , Michno Wojciech , Swartling Fredrik J , Holmberg Karl O , Giraud Géraldine 
Published: June 2024

Abstract

BACKGROUND
We established patient-derived xenografts (PDXs) from matched primary-relapse pairs of pediatric high-grade gliomas (pedHGGs) in collaboration with the Swedish Childhood Tumor Biobank. Further, we used human iPSC derived cortical organoids to evaluate interactions between glial and tumor cells under treatment pressure potentially lost in xenograft models. Using this setup, we hope to follow tumor relapse evolution and to identify novel mechanisms behind treatment evasion and relapse formation.

METHODS
Tumoral singel cell suspensions from matched primary-relapse pairs are injected orthotopically in immunodeficient NOG mice. We establish in vitro 2D models in stem cell conditions from the first generation of animals transplanted. Lentivirus-based labelling with GFP/Luciferase was done on PDX-derived cell lines to allow cell tracking and to quantify efficacy of drug screening efforts. Co-culture of these cells with normal cells in 3D assembloids were performed using 150-250 days old cortical organoids. Single-cell RNA sequencing and bulk RNA sequencing (RNA-seq) on patient biopsies, their corresponding PDXs from first generation of mice, and PDX-derived cell lines, was performed to track potential changes in vivo and in vitro and to further validate primary-relapse specific evolution.

RESULTS
2D and 3D cell cultures offered efficient labeling and we quantified differences in sensitivity to standard therapy between primary and relapse samples. PDX models and assembloids highlighted pedHGG growth patterns, modes of invasion and cell interactions, especially astrocyte-tumor cell interactions. These 3D models also allow for further validation of targeted drug testing based on multiomics data (WGS, methylation and RNA-seq) from the patient biopsies.

CONCLUSION
PedHGG primary-relapse in vitro 2D cell line/ in vivo 3D assembloid models together with PDXs is a robust approach to study different aspects of relapse-specific tumor biology. Our results offer insights aiding the development of novel therapeutics inhibiting relapse mechanisms already in the first line of treatment.
DIPG-33. COMBINING CLONAL TRACKING WITH SINGLE CELL RNA SEQUENCING REVEALS TEMPORAL SHIFTS IN CELL STATES ASSOCIATED WITH TRAMETINIB RESISTANCE IN MAPK ALTERED DIFFUSE MIDLINE GLIOMA
Authors: Das Molina , Grabovska Yura , Collins Jared , Rogers Rebecca , Burford Anna , Mackay Alan , Beroukhim Rameen , Bandopadhayay Pratiti , Jones Chris 
Published: June 2024

Abstract

BACKGROUND
H3K27-altered diffuse midline glioma (DMG) is an aggressive and incurable paediatric high-grade glioma with median overall survival of 9-12 months. A distinct subset of DMG harbour alterations in the MAPK pathway, and we have previously shown that DMG-MAPK may exhibit sensitivity to MEK inhibitors but develop resistance under long-term exposure to drug. Elucidating these resistance mechanisms could spearhead better treatment strategies for these patients.

METHODS
To study clonal evolution under trametinib, we used CloneSifter lineage tracking technology to uniquely barcode 300,000 DMG-MAPK cells which were then treated with a GI80 dose of trametinib for 11 weeks. We extracted DNA to quantify barcode enrichment at endpoint across six technical replicate experiments and leveraged CloneSifter’s compatibility with single cell RNA sequencing (scRNA-seq) to couple clonal identity with transcriptional states in ~90,000 trametinib treated cells at varying timepoints.

RESULTS
DNA sequencing revealed 0.5% (1500/300,000) of the initial barcodes were enriched across trametinib replicates and were also detectable by scRNA-seq. Conducting cNMF analysis on the single cell dataset showed populations of trametinib treated cells associated with each other in a temporal manner, whereby early and late-stage resistant populations were defined by neuronal and stem cell like markers, respectively. A time-dependent enrichment of CloneSifter barcodes was also observed, suggesting dynamic expansion of clones over the treatment window. Notably, week 11 trametinib treated cells showed higher expression of resistance driver genes related to EMT, stemness and p38/MAPK upregulation.

CONCLUSIONS
Utilizing the sequence-specific reporter construct built in to the CloneSifter system allows for retrieval of resistant clones marked by enriched barcodes under treatment prior to drug exposure, enabling further characterization of monoclonal populations of trametinib-resistant cells. In summary, we have employed novel tools to study resistance development in DMG-MAPK that could be exploited to devise rational treatment strategies for these patients in an evolutionary-guided manner.
DIPG-35. OVERCOMING THE BLOOD-BRAIN BARRIER CHALLENGE IN DIFFUSE MIDLINE GLIOMA
Authors: Tsoli Maria , Ung Caitlin , Upton Dannielle H , Venkat Pooja , Salerno Antonietta , Pandher Ruby , Mayoh Chelsea , Vittorio Orazio , Ziegler David S 
Published: June 2024

Abstract
Diffuse midline gliomas (DMGs) are aggressive paediatric brainstem tumours with no known cure. The development of effective treatments is greatly impeded by the failure of most anti-tumour agents to penetrate the blood-brain barrier (BBB). Our research, along with that of others, has revealed that the BBB remains intact in DMG. We employed DMG orthotopic models to explore potential region-specific variations in response to the therapeutic agent temsirolimus as well as confocal microscopy and single-cell RNA sequencing (scRNAseq) to elucidate the impact of DMGs on brain endothelial morphology and pathways governing BBB integrity. We first assessed the effectiveness of the mTOR inhibitor temsirolimus when administered in cortex-injected DMG models compared to brainstem-injected DMG. We found significantly increased survival rates, elevated temsirolimus levels, and reduced tumour cell proliferation in the cortex versus the brainstem. Confocal imaging analysis indicated no structural differences between DMG and Matrigel-injected animals. However, scRNAseq unveiled distinct transcriptomic changes: brainstem-injected DMG exhibited downregulation of genes related to inflammatory and apoptotic pathways, whereas cortex-injected DMG showed downregulation of interferon pathways. To overcome the tightened barrier in the brainstem, we explored three MCL1 inhibitors and SNGR-TNFa (targeting CD13) as potential blood-brain barrier modulators. These inhibitors significantly reduced transendothelial electrical resistance, increased tracer dye leakage in an in vitro DMG BBB model, and decreased the protein expression of claudin-5. Moreover, in vivo, we found that administration of a single dose of either SNGR-TNFa or the MCL1 inhibitor S63845 improved penetration of Texas-Red (3KDa) in DMG-engrafted animals, indicating the effective opening of the BBB. In summary, our study revealed that DMG directly affects BBB pathways in endothelial cells, tightening the barrier and reducing treatment efficacy. MCL1 inhibitors and SNGR-TNFa show promise in modulating the BBB and have the potential to enhance therapeutic activity.
DIPG-37. AUGMENTING RADIATION SENSITIVITY IN DMG/DIPG BY TARGETING TP53 DEPENDENCY AND INHIBITING DNA PROTEIN KINASE PATHWAY
Authors: Ciani Ludovica , Fernandez Solène , Grotzer Micheal , Müller Sabine , Nazarian Javad 
Published: June 2024

Abstract

BACKGROUND
Diffuse midlines gliomas (DMGs) are lethal pediatric brain tumors, with an overall survival rate of less than 12 months. Radiotherapy treatment (RT) only provides a transient clinical response, with an average survival increase of about 3 months. At the cell level it induces DNA damages, leading to tumor cell death. Although, DMGs are tumors known to be resistant to any therapy, as the tumor recurs most often within a few months post radiation. Peposertib, a DNA Protein Kinase (DNA-PK) inhibitor, is a potent radiosentitizer that crosses the blood brain barrier and has shown RT-combination efficacy in other cancers by enhancing DNA double-strand breaks (DSB) inducing agents including ionising radiation. Methods and

RESULTS
DNA-PK plays a key role in one of the main pathways involved in the repair of DNA double-strand breaks (DSB), allowing tumor cells to repair their DNA and continue proliferation. To further investigate Peposertib and its potential for clinical intervention, we explored Peposertib’s radiosensitizing activity on DMG preclinical in vitro models. In vitro viability assays with RT alone and in combination with Peposertib, were carried out using DMG cell lines carrying either the wild-type or mutated version of TP53. To further validate our results, immunofluorescence assays post-combination treatment were performed to assess DDR pathway disruption by studying the number of foci per nucleus of DNA damage markers yH2AX and P53BP1.

RESULTS
Remarkably, combinational treatment of Peposertib with RT resulted in a significant decrease in human primary DMG cells viability. Interestingly, Peposertib was effective in increasing RT sensitivity in TP53WT DMGs. However, the same good response was not observed in the DMG cell lines carrying TP53MUT, indicating a possible correlation between TP53 mutational status and response to therapy. Additionally, we demonstrated that Peposertib induces cell death. This was observed and determined through quantification analysis of DNA damage markers yH2AX and P53BP1 therefore to DDR pathway disruption.

CONCLUSIONS
Our current findings underscore Peposertib’s potential as a targeted therapeutic agent against DMGs, offering a better understanding of what drives resistance to radiotherapy. By targeting DDR pathway key factors we will increase sensitivity to radiation in vitro and in vivo in DMGs.
DIPG-39. ONCOHISTONE H3.3K27M-DRIVEN CREB5/ID1 AXIS DICTATES THE MALIGNANT CELL STATES OF DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG)
Authors: Zhou Wei , Xu Cheng , Tang Yujie , Pan Changcun , Zhang Liwei , Xi Qiaoran 
Published: June 2024

Abstract

BACKGROUND
Diffuse intrinsic pontine glioma (DIPG) is a highly aggressive pediatric cancer characterized by the presence of H3K27M-oncohistones, which drive relentless proliferation and differentiation arrest. This study focuses on the H3.3K27M DIPG subtype and investigates the role of the oncohistone-driven CREB5/ID1 axis in promoting malignancy.

METHODS
We employed a variety of biological in vitro assays and xenograft mouse models utilizing several H3.3K27M and H3.1K27M DIPG cell lines to evaluate the impact of the studied factors on the growth of DIPGs. Additionally, we employed methodologies in molecular biology, bioinformatics, drug screening, and biochemistry to elucidate the underlying mechanisms of tumorigenesis.

RESULTS
Through inhibition of ID1, this study explores the induction of cellular differentiation and apoptosis in H3.3K27M DIPG, shedding light on the oncogenic mechanisms at play. The intricate regulation of ID1, linked to CREB5—an oncogenic contributor independent of BMP signaling—is elucidated. The involvement of the SWI/SNF complex as a co-regulator of CREB5 is also examined. Moreover, our findings reveal that H3.3K27M-oncohistone triggers CREB5 overexpression, facilitating the formation of a super-enhancer promoter loop at the CREB5 locus. Disruption of this loop demonstrates potent anti-tumor efficacy in treating DIPG. Additionally, the combination of a compound targeting the CREB5/ID1 axis and a BRG1 inhibitor shows promise for DIPG treatment.

CONCLUSIONS
This research unveils key molecular pathways specific to the H3.3K27M DIPG subtype, offering valuable insights for potential therapeutic interventions against this lethal pediatric cancer. Inhibiting the CREB5/ID1 axis represents a promising strategy for inducing differentiation and apoptosis in DIPG cells, highlighting the potential for targeted therapies in combating this disease.
DIPG-44. DIFFUSE MIDLINE GLIOMA, H3K27-ALTERED: A COMPREHENSIVE CLINICAL AND BIOMOLECULAR LANDSCAPE OF THE NON-PONTINE TUMORS
Authors: Mariet Cassandra , Tauziède-Espariat Arnault , Auffret Lucie , Ajlil Yassine , Roux Alexandre , Pallud Johan , Palfi Stéphane , Métais Alice , Beccaria Kevin , Blauwblomme Thomas , Puget Stéphanie , Sanson Marc , Peloux Marie , Richard Juliette , Thalhammer Julian , Carvalho Alice , Puiseux Chloé , Pereira Victor , de Carli Emilie , Lesieur Thomas , Rouger Jeremie , Page Philipe , Doz François , Bourdeaut Franck , Dufour Christelle , Abou Samuel , Guerrini-Rousseau Léa , Dhermain Frédéric , Bolle Stéphanie , Varlet Pascale , Grill Jacques , Castel David 
Published: June 2024

Abstract

BACKGROUND
Since 2016, the WHO classification of CNS tumors groups all midline gliomas with H3K27me3 loss under the term diffuse midline glioma (DMG), H3K27-altered. Molecular characteristics enable their sub-classification based on driver mutations, co-driver mutations and epigenetic alterations. Predominantly studied in the pons (Diffuse Intrinsic Pontine Glioma, DIPG), where these are mainly pediatric tumors with a median overall survival (OS) of one year, fewer studies have been conducted on non-pontine DMG (npDMG), prompting this study to clinically and biologically characterize these gliomas and compare them with DIPG.

METHODS
Retrospective monocentric study from 1994 to 2022, including pediatric and adult patients diagnosed with npDMG, H327-altered with neuropathological confirmation at Sainte Anne Hospital in Paris, France. Comparative literature review of cases of npDMG and series of DIPG.

RESULTS
108 patients were included (54.7% male, median age 13.05-years [2.4-59.3]). The most frequent location was monothalamic (62.9%), followed by bithalamic, spinal, cerebellar, bulbo-medullar and other. H3K27M mutation was found in 85.2% of cases, EZHIP overexpression in 14.8% and EGFR alteration (mutation and/or amplification) in 16.7%. EZHIP-overexpressing patients were younger than H3K27M-mutated patients, as were EGFR-altered patients compared to those without EGFR alteration. Along with data from the literature, npDMG are older at diagnosis and have a slightly longer median OS (15 months [0.1-247.2]) than DIPG. Positive prognosis factors upon univariate analysis included longer time from symptom onset until diagnosis, treatment with ONC201, re-irradiation upon relapse, microcalcifications, proliferative index &gt;10%, MAP kinase alteration and absence of TP53 mutation and EGFR amplification. However, surgery quality did not impact OS.

CONCLUSIONS
npDMG is a heterogeneous group of gliomas, affecting all ages, which can develop in diverse locations, with an overall poor prognosis. Despite shared clinical, immuno-histochemical and molecular properties with DIPG, recent molecular biology advancements reveal distinct subtypes within DMG, with varying prognoses, challenging the unified classification.
DIPG-52. CEREBROSPINAL FLUID DIVERSION DOES NOT PROLONG OVERALL SURVIVAL IN CHILDREN WITH DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG): A REPORT FROM THE INTERNATIONAL DIPG REGISTRY
Authors: Manoharan Neevika , Cooney Tab , DeWire-Schottmiller Mariko , Lane Adam , Nellan Anandani , Leary Sarah , Partap Sonia , Kilburn Lindsay , Wright Karen D , Hummel Trent , Ziegler David S , Fouladi Maryam , Hoffman Lindsey M , Warren Katherine E 
Published: June 2024

Abstract

BACKGROUND
The role of permanent cerebrospinal fluid (CSF) diversion in the management of patients with diffuse intrinsic pontine glioma (DIPG) is poorly elucidated. There are no standard practice guidelines regarding the role of these neurosurgical interventions in patients with DIPG or large studies regarding the impact of CSF diversion on overall survival (OS) or palliation in this disease.

METHODS
Data were extracted from subjects registered in the International DIPG registry (IDIPGR). Univariable analyses were performed using the Fisher’s exact test or Wilcoxon rank sum test. Survival was estimated using the Kaplan-Meier method.

RESULTS
Of n=1104 evaluable patients with DIPG registered in the IDIPGR, n=303 (27.4%) had permanent CSF diversion. Median time from diagnosis to CSF diversion was 1 month (range 0-4 months). There were no significant differences in age, gender or race in subjects with CSF diversion versus no CSF diversion. Patients with CSF diversion had a higher incidence of hydrocephalus at diagnosis (64.1% vs 11.3%, p&lt;0.001). There was no significant difference in OS or post-progression survival (PPS) at 1,2 and 3 years between subjects with permanent CSF diversion compared to those without (p=0.5 and p=0.8, respectively). Median OS was 11 months in both. Median PPS was 7 months (no CSF diversion) and 6 months (CSF diversion). Patients reported less headache and vomiting after permanent CSF diversion compared to pre-diversion (p&lt;0.0001), however steroid use was also significantly higher after CSF diversion (p&lt;0.001).

CONCLUSIONS
In this, the largest reported international cohort of patients with DIPG with permanent CSF diversion, we show that permanent CSF diversion was not associated with an improvement in OS or PPS. CSF diversion improved headache and vomiting but was also associated with increased rates of steroid use. This highlights the need for consensus guidelines regarding the use of these diversion strategies in patients with DIPG.
DIPG-54. PREDICTING EARLY DEATH IN DIFFUSE MIDLINE GLIOMA
Authors: Moloney Sam , Carruthers Vickyanne , Davis Melissa J , Bhuva Dharmesh D , Mignone Cristina , Singh Susan , Gardiner Rebecca E , Valvi Santosh , Eisenstat David D , Hansford Jordan R 
Published: June 2024

Abstract

BACKGROUND
Diffuse midline glioma (DMG) is an invariably fatal diagnosis with a median survival of 9-11 months. While early death is uncommon, such cases do exist. Identification of children at risk of short-term survival can support clinicians to provide informed counselling to families regarding important treatment decisions.

METHODS
We identified patients with a radiological diagnosis of DMG at the Royal Children’s Hospital (Melbourne) and the Women’s and Children’s Hospital (Adelaide) between 2001-2023. Clinical, imaging, and histopathological data were abstracted and compared between short-term survivors (STSs) and longer survivors (LSs).

RESULTS
Among 89 patients included, 21 (24%) had an overall survival (OS) of &lt; 6 months of which 7 (8%) had an OS &lt; 3 months. 5 of these cases had dramatic early death with &lt; 1 month since diagnosis. While neither the pattern nor presence of contrast enhancement were predictive of poor survival, STSs were found to have a larger volume of contrast enhancement on T1-weighted imaging compared to LSs (1.3 cm3 vs 0.2 cm3, p &lt; 0.01). Evaluation of the presence and extent of intratumoural susceptibility signals (ITSS) on susceptibility weighted imaging (SWI) demonstrated higher grades of ITSS (&gt; 5 foci) were strongly associated with poor survival (p = 0.01, median OS = 5.5 months). Furthermore, 50% (6/12) of STSs had ≥ 11 dot-like or fine linear ITSSs in a maximum tumour cross section. From a treatment standpoint, as expected, patients who did not receive upfront radiotherapy experienced significantly worse OS (3.4 months vs 10.4 months, p &lt; 0.01). Notably, a number of STSs did not receive palliative therapy in the context of their rapid and unforeseen disease progression.

CONCLUSIONS
The preliminary findings from this multi-centre study provide the foundation for future exploratory analysis alongside international collaborators at the DMG/DIPG registry to improve prognostication for patients with high-risk features of early death.