bluuebunny/crossref_metadata_2025_split huggingface dataset:
DIPG-38. VAL-083 IN COMBINATION WITH AZD1775 FOR THE TREATMENT OF DIFFUSE MIDLINE GLIOMA
Authors: Subramaniam Bavani , Roy Debasish , Woldegerima Ayda , Przystal Justyna , Zhang Jie , Laternser Sandra , Kritzer Bettina , Yadavilli Sridevi , Mueller Sabine , Packer Roger , Nazarian Javad 
Published: June 2024

Abstract

BACKGROUND
Diffuse midline gliomas (DMGs) are malignant pediatric brain tumors characterized by H3K27M mutation and global genome hypomethylation. This results in enhanced transcription of MGMT, a DNA-repair enzyme, rendering alkylating chemotherapeutics ineffective. Therefore, we investigated the efficacy of a functionally different DNA damaging agent, Val-083, that induces double strand breaks and triggers S/G2 phase cell cycle arrest for homologous DNA repair. We further evaluated its combined efficacy with Wee1 (G2/M checkpoint) inhibitor, AZD1775, to override cell cycle arrest and propel cells with DNA damage into premature mitosis and apoptosis.

METHODS
DMG cells were treated with increasing concentration of Val-083 and/or AZD1775 and their viability was evaluated using CellTiter-Glo luminescent assay. Next, the drugs’ mechanisms of action were investigated by immunoblotting for biomarkers involved in DNA damage response and cell cycle arrest. Flow cytometry was used to investigate cell cycle profile and apoptosis. Additionally, in vivo tumor growth inhibition and survival benefit were evaluated using zebrafish and mouse xenograft DMG models.

RESULTS
The IC50 values of Val-083 range between 0.69 and 4.38 µM while the IC50 values of AZD1775 range between 0.22 to 0.98 µM. Combination of both drugs showed high areas of synergy on multiple DMG lines, DNA double strand breaks and significant increase in cell population at the S (p&lt;0.01) and G2/M (p&lt;0.05) phases. Importantly, on zebrafish xenograft tumor model, combination treatment significantly (p&lt;0.001) inhibited tumor growth in comparison to control and single treatment groups. Furthermore, the combined treatment demonstrated significant (p&lt;0.01) survival benefit (median survival (MS) = 62 days) on tumor-bearing nude mice models, in comparison to vehicle (MS= 44 days), Val-083 (MS= 54.5 days) and AZD1775 (MS= 47 days) treatment groups.

CONCLUSION
Val-083 in combination with AZD1775 demonstrate promising efficacy in DMG preclinical models, providing a strong rationale for positioning these arms for clinical testing.
DIPG-43. CHARACTERIZATION OF THE BLOOD BRAIN BARRIER IN DIPG MURINE MODELS AND EFFECT OF ULTRASOUND ON ITS SPECIFICITIES AND PERMEABILITY TO ASIDNA™
Authors: BIARD adam , LE Ludivine DRET , Marie DUTREIX , Alexandre CARPENTIER , Manon LANCIEN , Alexandre PELLISSIER , Marie-Anne Debily , David CASTEL , Jacques GRILL , Kevin BECCARIA 
Published: June 2024

Abstract

BACKGROUND
The poor prognosis of pediatric diffuse midline gliomas, including diffuse intrinsic pontine gliomas (DIPGs), is partly due to the blood-brain barrier (BBB). The BBB can be opened by ultrasound (US), but few studies have focused on its characteristics in DIPGs, especially when submitted to US. We aimed to characterize the BBB in DIPGs and the influence of US on its characteristics, and to evaluate the effect of US-induced BBB opening on the kinetics of AsiDNA™ in DIPG murine models.

METHODS
US-induced BBB opening was performed with the SonoCloud® device and controlled with Evans blue dye. Permeability of DIPGs’ BBB was assessed with fluorescent dextrans. A histological evaluation of BBB markers was carried out by immunohistochemistry and immunofluorescence, including endothelial markers (CD34, GLUT1, PLAVP), tight junctions proteins (claudin 5, Zona occludens 1), and the efflux transporter ABCB1. An in vivo and ex vivo kinetic study of AsiDNA™ was performed with fluorescence.

RESULTS
We could repeatedly open the BBB with low intensity US (acoustic pressure 0.4 Mpa). In vivo, 3 kDa and 70 kDa dextrans delivery to DIPG tissue was increased by US-induced opening of the BBB, while 500 kDa dextrans did not cross the BBB spontaneously or after US. ABCB1 gene expression was variable at baseline in different DIPGs but was downregulated after US-induced BBB opening. The spontaneous passage of AsiDNA™ through the BBB was limited but could be increased after US-induced BBB opening.

CONCLUSIONS
We have shown that the BBB was specific in DIPG murine models, particularly in the expression of ABCB1. This BBB can be modulated and permeabilized by US, a technique that could allow for an improved delivery of AsiDNA. This study is a preliminary step before the introduction of a such technique and treatment in future clinical trials in children and adolescents with DMGs.
DIPG-46. TOTAL THERAPY FOR DIFFUSE MIDLINE GLIOMAS: A SEQUENTIAL, INTENSIVE, MULTI-AGENT COMBINATION PLATFORM IS A POTENT TREATMENT STRATEGY
Authors: Khan Aaminah , Upton Dannielle , Gopalakrishnan Anjana , Chen Yongjuan , Tsoli Maria , Ziegler David S 
Published: June 2024

Abstract

BACKGROUND
Diffuse Midline Glioma (DMG) has a dire prognosis, with a mortality rate nearing 100%. In the past, children diagnosed with Acute Lymphoblastic Leukemia (ALL) faced a similar prognosis until multi-agent chemotherapy revolutionized their survival rates. We hypothesized that implementing a comprehensive treatment strategy for DMG could yield similar efficacy. This study aimed to test the safety and efficacy of sequential, intensive, multi-agent combinations targeting epigenetic/chromatin modification (CBL0137-Panobinostat, CP), polyamine metabolism (DFMO-AMXT1501, DA), and the NF-κB pathway (ACT001) in preclinical DMG models.

METHODS/RESULTS
Maximum tolerated dose studies, which integrated comprehensive biochemical and hematological analyses with clinical data, tested different treatment durations and drug sequences. Tolerable doses and drug sequences were assessed in the aggressive patient-derived SU-DIPGVI orthotopic model for activity. In total six different drug combination sequences were tested for impact on survival. One particular sequence – DA/ACT001/CP – was significantly more effective compared with both vehicle and other regimens. This specific sequential regimen resulted in a 50% tumour regression rate with surviving animals maintaining tumor-free status &gt; 1 year, compared with 81-day survival in controls. This 5-agent treatment sequence (DA/ACT001/CP) was next tested in the HSJD-DIPG007 orthotopic model with a significant extension of survival (119 days) compared with single or two-agent treatments (vehicle-59 days, DA-86 days, ACT001-66 days, CP-62 days, DA/ACT001-93 days). Further enhancement of this treatment regimen through addition of radiotherapy significantly extended survival to 130 days, with one-third of the cohort showing sustained tumor regression and remaining tumor-free (by Xenogen imaging) for &gt; 220 days.

CONCLUSIONS
There are no effective therapies for DMG. Single and combination regimens in vivo often extend survival by days or weeks but do not generally eliminate tumors. Our “Total Therapy” strategy, inspired by successful ALL therapies, suggests that multi-agent sequential combination therapy can induce profound responses and unprecedented long-term survival in DMG animal models.
DIPG-55. DISSECTING THE ECOSYSTEM OF PEDIATRIC DIFFUSE MIDLINE GLIOMA
Authors: Morscio Julie , Jacobs Sandra , De Smet Frederik 
Published: June 2024

Abstract

BACKGROUND
Pediatric gliomas are heterogeneous tumors encompassing high grade (pHGG) and low grade (pLGG) subtypes. For tumors not amenable to surgery, in particular high grade H3K27 mutant diffuse midline glioma (DMG), no curative options exist. DMG is characterized by 1) extensive heterogeneity of tumor cells that can exist in different interchangeable cellular states mimicking normal development and 2) extensive heterogeneity of the tumor microenvironment (TME). A better understanding of the DMG ecosystem is needed for therapeutic target identification.

METHODS
Publicly available single cell RNA seq data of DMG (n=17, Jessa et al. Nat. Genet. 2022), high grade pediatric glioblastoma (GBM, n=16, scPCA) and low grade tumors (ganglioglioma, n=5; pilocytic astrocytoma, n=14, scPCA) were analyzed to define key molecular characteristics and differences between these pediatric brain tumors. Doublet cells were removed from each dataset and tumor and TME cells were discriminated based on marker gene expression and inferred CNVs.

RESULTS
In DMG, glioma cellular states and TME heterogeneity differed depending on the tumor location. DMG arising in the pons harbored a bigger fraction of astrocyte-like glioma cells whereas oligodendrocyte-like cells were more abundant in thalamic tumors. In line with this observation, Liana cellular communication analysis inferred more intratumoral (autocrine) signaling involving oligodendrocyte-like glioma cells in thalamic tumors (e.g. NCAM1-PTPRZ1, NLGN4X-NRXN1, NTN1-DSCAM) than in pons tumors. Notably, the TME of thalamic tumors contained a bigger fraction of immunotolerant macrophages expressing CD163 or VSIG4. In contrast, pons tumors harbored a unique cluster of VEGFA expressing astrocytes, not found in GBM or pLGG. Liana analysis inferred COPA/APP-CD74 interaction between VEGFA+ astrocytes and CD163/VSIG4+ macrophages and microglia, potentially contributing to an immunotolerant TME in pons DMG.

CONCLUSIONS
In DMG, patterns of tumor and TME composition associated with tumor location were uncovered. Furthermore, unique TME celltypes could contribute to the particularly aggressive nature of these tumors.
DIPG-56. BRAINSTEM TUMOR BIOPSY: A SINGLE INSTITUTE EXPERIENCE OF SAFETY AND FEASIBILITY IN A LOW-MIDDLE INCOME COUNTRY (LMIC)
Authors: Bashir Farrah , Hussain Muzamil Hamid , Javed Gohar , Bari Ehsan , Enam Ather , Qureshi Bilal Mazhar , Sirat Shayan , Thomas Diana , Drissi Richard , Khan Sara , Fouladi Maryam , Hawkins Cynthia , Minhas Khurram , Bouffet Eric , Mushtaq Naureen 
Published: June 2024

Abstract

BACKGROUND
Brainstem tumors account for 10-15% of all pediatric central nervous system tumors and carry a dismal prognosis. These include a wide spectrum of histological diagnosis therefore, in most specialized centers stereotactic biopsies for brainstem tumors are considered safe and standard practice. However, this approach continues to pose a challenge in LMIC’s.

METHODS
We retrospectively reviewed data of patients presenting with brainstem tumors at Aga Khan University Hospital, Pakistan, between 2014 and 2023. In addition to histopathological analysis, whole-genome sequencing and RNA sequencing were also performed on 6 tumors.

RESULTS
We identified 39 patients with brainstem tumors; amongst these 56.4% were females. Median age at diagnosis was 9 years (IQR: 5.1-11). Most cases presented with walking difficulty (74%) and cranial nerve palsies (46%). Median duration of symptoms was 30 days (IQR: 20-60). On imaging large proportion were intrinsic pontine tumors (53.8%) followed by brainstem (30.8%) and cerebellopontine angle (15.4%). 21 patients underwent stereotactic biopsy with 86% performed after 2016. 43% were intrinsic pontine tumors. Histopathology analysis showed a wide spectrum with diffuse midline glioma in 28% of cases, pilocytic astrocytoma, anaplastic astrocytoma and ganglioglioma in 33%, 14% and 9% of cases respectively. Rare entities identified included embryonal tumor with multilayered rosettes, atypical teratoid rhabdoid tumor and schwannoma (5%). Biopsies were uneventful in 81% of cases. Complication of biopsy in 2 patients included cranial nerve palsy and subdural hemorrhage. No patient died due to complications of biopsy. Surgical and medical management was altered in 9 patients due to availability of histological diagnosis.

CONCLUSIONS
We present the first study demonstrating safety and feasibility of stereotactic biopsy for brainstem tumors in LMIC. These biopsies should be considered for atypical brainstem tumors and should be performed in well-equipped tertiary neurosurgical facilities by trained neurosurgeons in LMIC.
DIPG-62. REPURPOSING OF ANTIPSYCHOTIC TRIFLUOPERAZINE FOR INHIBITING MITOCHONDRIAL FUNCTION IN DIFFUSE MIDLINE GLIOMA
Authors: Petrovic Antonela , Wojnicki Kamil , Laternser Sandra , Kitanovic Ana , Kleele Tatjana , Grotzer Michael , Müller Sabine , Nazarian Javad 
Published: June 2024

Abstract

BACKGROUND
Diffuse Midline Gliomas (DMGs) present formidable challenges in neuro-oncology, prompting the exploration of innovative therapeutic strategies. Repurposing approved drugs, particularly those exhibiting multifaceted effects, holds promise for addressing these challenges efficiently. In this study, we investigate the potential of trifluoperazine (TFP), an antipsychotic medication, with a specific focus on its mitochondrial-targeted actions in DMGs.

METHODS
TFP, a phenothiazine derivative, displayed robust in vitro anticancer activity against DMGs. Our investigation explored the molecular mechanisms underlying TFP’s interaction with mitochondria, emphasizing its influence on mitochondrial function, membrane potential, and reactive oxygen species (ROS) production. TFP is well known to induce irreversible Ca2+ release from intracellular stores by directly interacting with calmodulin 2 (CaM2) at the inositol triphosphate receptor (IP3R), leading to IP3R opening. In DMGs, intracellular Ca2+ plays a pivotal role in gene expression, cell motility, differentiation, and survival. TFP disrupts calcium homeostasis by elevating intracellular Ca2+ concentration, thereby inhibiting DMG invasion and growth. DMG cell lines, exhibiting heightened CaM2 expression compared to control healthy astrocyte cells, display increased sensitivity to TFP.

RESULTS
Remarkably, mitochondrial homeostasis was seriously affected by TFP, and a loss of mitochondrial membrane potential, ROS overproduction and fragmentation of mitochondrial network was observed. This mitochondrial stress, coupled with ER stress, activated the integrated stress response. We demonstrated that TFP induces cell death triggered by a poor ATP content, observed in TFP-treated cells as a consequence of a dramatic decrease in OXPHOS metabolism due to mitochondrial stress.

CONCLUSIONS
Our findings underscore TFP’s potential as a targeted therapeutic agent against DMGs, offering a better understanding of its impact on mitochondrial and intracellular signaling pathways. As the mitochondrial landscape remains critical in DMG biology, the observed mitochondrial damage-induced oxidative stress provides valuable insights for future investigations into the clinical application of TFP in neuro-oncology.
DIPG-64. UNRAVELING H3K27M INTERACTIONS IN DIFFUSE MIDLINE GLIOMA
Authors: Liapodimitri Athanasia , Lunsford Kayleigh , Tetens Ashley R , Craig-Schwartz Jordyn , Vesuna Farhad , Raman Venu , Koldobskiy Michael A 
Published: June 2024

Abstract

BACKGROUND
Diffuse midline glioma (DMG) harboring the histone H3 K27M mutation, also known as diffuse intrinsic pontine glioma when it occurs in the pons, is a uniformly fatal pediatric brain tumor. We sought to better understand protein-protein interactions of the mutant histone in DMG.

METHODS
To address this, we carried out endogenous co-immunoprecipitation of histone H3 K27M from patient-derived DMG neurosphere cell lines, followed by LC-MS/MS identification of binding partners, and validation of binding by Western Blot. Moving beyond identification, we investigated the functional consequences of these interactions.

RESULTS
We identified putative novel interactors of H3 K27M with notable binding partners including histone chaperones and RNA helicases of the DDX family. We then explored the disruption of downstream effects resulting from this interaction by pharmacologically inhibiting DDX3 using the small molecule inhibitor RK-33, and assessed impact on viability and radiation sensitivity.

CONCLUSIONS
Understanding the protein interactome of the mutant histone can inform alternative ways for targeting DMG, thus enriching the therapeutic toolbox against this aggressive tumor. Functional characterization of binding partners holds the potential to identify novel therapeutic targets that cooperate with H3 K27M. The use of inhibitors targeting these partners could specifically destabilize oncohistone-dependent homeostasis and survival pathways and increase sensitivity to radiation and other therapies.
DIPG-65. NOVEL PATIENT-BASED PHARMACOKINETIC DRUG SCREENING REVEALS GEMCITABINE POTENTIAL IN PEDIATRIC H3K27-ALTERED DIFFUSE MIDLINE GLIOMAS
Authors: Scheffers Liska M , Bianco John , Su Yan , Ringnalda Femke C A , de Lange Elizabeth C M , Huitema Alwin D R , van Vuurden Dannis G 
Published: June 2024

Abstract

BACKGROUND
Pediatric H3K27-altered diffuse midline glioma (DMG) remains incurable, with median overall survival of less than one year. Ineffectiveness of chemotherapy is largely attributed to the blood–brain barrier, hindering drug exposure to the tumor. Current drug sensitivity testing use concentrations vastly different from those attainable in the human brain, with optimal combination, timing, and sequence of drugs remaining underexplored. This study aims to systematically select and validate EMA/FDA approved drugs for effective treatment of DMG, based on human pharmacokinetics.

METHODS
In silico anticancer drug pharmacokinetic (PK) properties were correlated with published DMG cell sensitivities and ranked based on therapeutic index potential. Predictions of brain extracellular fluid time-concentration profiles (AUChumanECF) using plasma PK values of drug candidates, corresponding to human values, were made via physiologically based pharmacokinetic (PBPK) modeling with LeiCNS-PK3.0. In vitro cellular treatment protocols were established that mimic clinically achievable AUChumanECF, to be validated in vivo.

RESULTS
This PBPK drug screening approach revealed gemcitabine as a highly potent drug for DMG therapy for most cell lines tested (AUCplasma/AUCin_vitro = 337.6±233.0). Replicating a phase I clinical study in pediatric leukemia patients (3 weekly courses of 3600 mg/m2), 3 weekly 6-hour exposures to 12.5 µM.h gemcitabine demonstrated up to 99% cell kill as compared to viability at start of treatment. Notably, the cytotoxic effects of gemcitabine became apparent 3-5 days following drug exposure for most cell lines, and would have been missed using conventional drug screening with direct readouts.

CONCLUSIONS
This human PBPK-based drug screening approach underscores the significance of precise timing and dosing in elucidating clinically relevant therapeutic effects, highlighting high-dose gemcitabine as a potential therapy for DMG. Cytotoxic effects of gemcitabine on DMG cell viability are cumulative, and undetected when using conventional drug screening. This underlines the importance of investigating real-life human exposure patterns in the context of DMG.
DIPG-66. MULTIPLEXED IMMUNOFLUORESCENCE MAPPING AND AI MODEL PREDICTION OF TUMOR MICROENVIRONMENT IN DIFFUSE MIDLINE GLIOMAS
Authors: Laternser Sandra , De Micheli Andrea Joseph , Petrovic Antonela , Brüningk Sarah , McDonough Elizabeth , Surrette Christine , Ginty Fiona , Eze Augustine , Dettwiler Susanne , Prutek Fabiola , Lagar Noelia Casares , Morinigo Denise , Bornhorst Miriam , Rushing Elisabeth Jane , Grotzer Michael , Stücklin Ana Sofia Guerreiro , Müller Sabine , Packer Roger , Rodan Marta Maria Alonso , Nazarian Javad 
Published: June 2024

Abstract

BACKGROUND
Diffuse midline glioma (DMG) is a fatal childhood brain cancer with a survival rate of less than one year from diagnosis. Pharmacological approaches and immunotherapy have failed to make a clinical impact. Incomplete understanding of the tumor microenvironment (TME) and tumor associated antigens have contributed to the observed poor prognosis. Therefore, mapping TME is urgently needed.

METHODS
Whole brains were collected at autopsy from 80 pediatric subjects, including patients diagnosed with DMG (n=50), GBM (n=9), non-malignant controls (n=10), ependymoma (n=5), ATRT (n=2). Up to four brain anatomical sites were selected: primary tumor, metastatic and adjacent healthy control sites, and processed for staining with hematoxylin and eosin (H&E). After reviewing the tumor and healthy regions, three punch cores were obtained resulting in a total of 918 core punches and two TMA blocks. Multiplexed immunofluorescence (MxIF) technology was used to probe 43 biomarkers on a single TMA slide, focusing on immune cell types and activation thereof. Clinical data including genomics alterations were obtained from each patient for downstream analyses.

RESULTS
Highest expressed immune markers across all patients were CD8 and CD3 (T-cells), CD68, Iba1 and CD163 (microglia). In DMGs, T-cells were mostly detected and increased in ONC201 and immunotherapy treated patients compared to only immunotherapy treated patients. Analysis of Iba1 confirmed a higher difference in activation in primary tumor compared to metastatic and adjacent healthy tissue, whereas in contrast, CD68 was significantly increased in metastatic sites. Patient plasma and RNA transcriptome analysis confirmed biomarkers and immune related pathways. Further, immune competent murine models were used to validate immune cell infiltration. AI deep learning technology modeling is ongoing now to, in future, be able to predict cell type composition and neighborhoods mapping.

CONCLUSION
We posit that this comprehensive data and characterization of the DMG TME will help to identify biology-informed targeted treatments.
DIPG-70. NQO1 AS A RESISTANCE DRIVER AND THERAPEUTIC TARGET IN DMG
Authors: Lupien Leslie E , Morin Eric , Zhang Daren F , Novikov Dana R , Chacon Madison S , Khuu Nicholas , Keshishian Hasmik , Seidel Olivia , Carr Steven A , Goodale Amy , Persky Nicole S , Root David E , Cusick Margaret , Ligon Keith L , Beroukhim Rameen , Phoenix Timothy M , Rendo Veronica , Bandopadhayay Pratiti 
Published: June 2024

Abstract
p53 pathway reactivation through pharmacologic inhibition of negative regulators was identified as a promising therapeutic strategy for TP53 wild-type (WT) high-grade gliomas, including Diffuse Midline Gliomas (DMGs). Despite widespread theoretical promise, the therapeutic efficacy of MDM2 inhibitors and PPM1D inhibitors as single agents have each been limited by issues, including sub-lethal effects on cancer cells and innate or emerging resistance leading to tumor progression. We carried out a genome-scale CRISPR activating (CRISPRa) screen to identify genes that, when overexpressed, confer resistance to p53 reactivation therapies. NAD(P)H quinone dehydrogenase 1 (NQO1) emerged as a top hit and was confirmed through secondary CRISPRa screens and low-throughput validations as driving a resistance phenotype in TP53 WT DMGs. Our subsequent work has aimed to elucidate the mechanisms through which NQO1 mediates the effects of p53 reactivation therapies, and assess the feasibility and impact of exploiting NQO1 in combination therapies towards a cure.