bluuebunny/crossref_metadata_2025_split huggingface dataset:
ATRT-18. ELUCIDATING THE ETMR MICROENVIRONMENT USING SPATIAL MULTI-OMICS TECHNOLOGIES
Authors: Liapis Evangelos , Pamreddy Annapurna , O’Neill Kelly , Maas Allison , Hanson Derek , Carter Claire 
Published: June 2023

Abstract
Embryonal tumor with multilayered rosettes (ETMR) is a highly aggressive CNS neoplasm that occurs almost exclusively in infants under 4 years of age and is associated with an extremely poor prognosis. A bottleneck in the development of new and curative treatments for ETMR stems from our limited understanding of the spatiotemporal biological heterogeneity within patient tumor samples and a lack of preclinical models that adequately reflect the entire biological spectrum. Novel lipid-based therapeutics that encompass ganglioside-directed immunotherapy, targeting lipid metabolism and membrane lipid therapy, have shown efficacy in the treatment of brain tumors but have yet to be evaluated in the treatment of ETMR. We carried out mass spectrometry imaging on ETMR patient samples to identify the histology-specific accumulation of lipids within the diverse cell populations of the tumor microenvironment. Our preliminary studies identified the accumulation of glycosphingolipids, cardiolipins, phosphatidylinositols, and ceramide-1-phosphates within tumor cells, including the characteristic multilayered rosettes, and within different microvascular proliferations. All data were correlated to histopathology and Ki67 proliferation index. We next evaluated the lipid profiles in the patient-derived ETMR cell line, BT183, compared to control neural stem cells (NSCs), grown as 3D tumorspheres and neurospheres, respectively. From this data we identified lipids that accumulated in our patient samples and the ETMR cell line but were significantly reduced or not detected in the control NSCs. Analysis aimed at a systems biology approach to study the ETMR microenvironment using imaging mass cytometry for multiplex IHC and spatial transcriptomics to correlate lipidomic phenotype to distinct cell populations within the microenvironment are ongoing. Preclinical model development based on these findings and drug screening of therapeutics targeting these lipidomic pathways are also ongoing.
BIOL-07. DISTINCTIVE FEATURES OF HIGH-GRADE GLIOMA MOUSE MODELS REVEALED BY SINGLE-NUCLEUS RNA-SEQUENCING GUIDE PRE-CLINICAL MODEL SELECTION
Authors: Ernst Kati , Okonechnikov Konstantin , von Soosten Laura , Hofmann Nina , Mack Norman , Schwalm Benjamin , Wechsler-Reya Robert J , Pfister Stefan M , Thongjuea Supat , Jones David T W , Zuckermann Marc 
Published: June 2023

Abstract
Glioma is the most common pediatric central nervous system tumor, with high-grade gliomas (HGG) having one of the worst prognoses of all human cancers. In order to develop better diagnostics and therapies, it is essential to use faithful disease models. Currently, highly passaged patient-derived xenograft (PDX) models are most widely used in preclinical studies, although alternative immunocompetent models are becoming increasingly available. Here, we compare several in vivo glioma models on a single-cell level and investigate their similarity to primary human tumors. Single-nucleus sequencing was used to analyze &gt;125,000 nuclei of primary patient samples, xenografts, autochthonous mouse tumors and related allografts including early and late in vivo passages – with a focus on MET-fusion-driven as well as H3 K27M-mutant HGG. Transcriptomic profiles of single tumor cells and associated stromal/immune components reveal insights into model-specific intratumoral heterogeneity, tumor evolution, and similarities between mouse models and patient samples. In addition, matched tumors engrafted into immunocompromised and immunocompetent animals are used to examine tumor-immune crosstalk and the modifying role of the tumor microenvironment. This improved understanding of how the analyzed model systems evolve over time and how they reflect patient’s tumor compositions will allow to prioritize and refine modern preclinical trials.
BIOL-15. PATIENT-DERIVED XENOGRAFTS OF MATCHED PRIMARY-RECURRENT PEDIATRIC BRAIN TUMORS AS A RESOURCE FOR IDENTIFYING THERAPY RESISTANCE PROFILES
Authors: Zhao Miao , Olsen Thale , Bergström Tobias , Rosén Gabriela , Dalmo Erika , Vikström Elin , Larsson Ida , Lin Tina , Sundström Anders , Holmberg Karl , Weishaupt Holger , Nelander Sven , Giraud Geraldine , Swartling Fredrik 
Published: June 2023

Abstract
Tumor recurrence developing from therapy resistance, immune escape and metastasis is the leading cause of death of malignant pediatric brain tumors. By studying paired primary-recurrent patient samples we previously identified significant accumulation of SOX9-positive cells in Group 3 medulloblastoma that was similarly induced following long-term irradiation in transgenic mouse models of MYC-induced medulloblastoma.
To follow relapse biology in malignant pediatric brain tumors at the single cell level we have established patient-derived xenografts (PDXs) from a number of matched primary-relapse samples, including pediatric high-grade glioma, medulloblastoma and ependymoma profiled with DNA methylation analysis. We next used scRNA-Seq to identify clones with particular expression of genes and distinct signaling pathways enriched in recurrent tumor cells as compared to their matched primary tumor cells. We further used a lentivirus-based barcoding strategy coupled to scRNA-Seq to study the molecular evolution of cell clones arising from genetically modified mouse models and PDXs that survive long-term fractionated irradiation, cisplatin or temozolomide treatment in vitro and in vivo.
By using computational modeling we identified means of specific targeting of recurrent cells that could be of potential use in future treatments for patients affected by fatal relapses. Our results suggest that pediatric brain tumors of distinct tumor entities use different ways to acquire therapy resistance in patients which is often coupled to an expansion of clones that are developing therapy-induced resistance.
BIOL-16. OBESOGENIC DIET EXPOSURE INCREASES NF1-OPTIC PATHWAY GLIOMA FORMATION IN PART THROUGH EFFECTS ON THE CELL OF ORIGIN
Authors: Chan Ambrose , Zhang Kailong , Martin Gemma , Gutmann David , Brossier Nicole 
Published: June 2023

Abstract
Pediatric low-grade glioma incidence has been rising in the U.S. over the last 20 years, concurrent with a rising rate of obesity in both the adult and pediatric populations. Recently, children of obese mothers have been demonstrated to have increased rates of several tumors, including brain tumors. Importantly, obesity in the U.S. is driven in large part by diet, given the abundance and accessibility of high-fat, high-sugar food choices. High-fat diet exposure has been previously demonstrated to promote proliferation and glial differentiation of embryonic neuroglial progenitor cells (NPCs) around the third ventricular zone (TVZ), suggesting that in utero exposure to an obesogenic diet might affect the formation of pediatric tumors derived from these cells, such as Neurofibromatosis Type 1 (NF1)-related optic pathway glioma (OPG). Based on these data, we hypothesized that maternal obesogenic exposure would increase Nf1-OPG formation through intrinsic effects on the tumor cell of origin. We demonstrated that progeny from obese dams exposed to HFHS diet during and preceding gestation demonstrated increased proliferation and glial differentiation of WT and Nf1-heterozygous TVZ NPCs in vivo. Progeny of non-obese dams exposed to this diet during gestation demonstrated a similar phenotype, suggesting these effects were related to maternal diet rather than weight. We then assessed how obesogenic diet exposure affected tumor formation. We determined that this exposure increases glioma penetrance in two low-penetrance models of NF1-OPG. Finally, we demonstrated that obesogenic diet exposure resulted in earlier tumor onset in a high-penetrance Nf1-OPG model. Taken together, these findings suggest that obesogenic diet exposure increases pediatric glioma formation, in part through effects on the tumor cell of origin while still in utero. It may also have implications for clinical prognosis, as earlier age of tumor onset has been negatively associated with visual outcomes in NF1-OPG.
BIOL-17. DISSECTING THE EXPRESSION AND FUNCTION OF ANGIOPOIETIN-1 IN PEDIATRIC BRAIN TUMORS
Authors: Langhnoja Jaldeep , Wei Xin , Arounleut Phonepasong , Kundu Ipsita , Phoenix Timothy 
Published: June 2023

Abstract

BACKGROUND
Angiopoietin-1 (Angpt1) is a secreted protein that promotes angiogenesis and vascular stability in development and certain disease states through activation of the Tie2 receptor. However, little is known about its expression or function within pediatric brain tumors.

METHODS
We utilized available datasets from patient samples and created murine models of pediatric high-grade glioma and ependymoma by in utero electroporation. Using a combination of transcriptomics and Angpt1-GFP reporter tumor models we evaluated Angpt1 expression across different types of pediatric brain tumors. We also applied inducible Angpt1 floxed mice to generate tumor-specific knock-out models.

RESULTS
Angpt1 is upregulated in glial brain tumors, including high-grade gliomas and ependymomas. We find Angpt1 is expressed by specific cell populations within gliomas and ependymomas, along with non-tumor reactive astrocytes and perivascular mural cells. Leveraging our in vivo brain tumor platform we have created tumor specific Angpt1 knock-out models by including a plasmid expressing Cre-recombinase. Ongoing studies aim to delineate the function of Angpt1 in tumor pathogenesis, including tumor angiogenesis and blood-brain barrier function.

CONCLUSION
Current work finds that Angpt1 is upregulated in glial brain tumors and nominates it as a potential modulator of brain tumor vascular biology, including tumor angiogenesis and permeability.
BIOL-21. PATIENT-DERIVED, THREE-DIMENSIONAL ORGANOID PLATFORM FOR PEDIATRIC BRAIN TUMOR MODELING AND THERAPEUTIC TESTING
Authors: Beale David , Baubet Valerie , Goel Peeyush , Patterson Luke , Jacob Fadi , Santi-vicini Maria-Rita , Viaene Angela , Ming Guo-li , Song Hongjun , Madsen Peter , Foster Jessica , Griffin Crystal , Stern Ally , Storm Phillip , Koptyra Mateusz , Resnick Adam 
Published: June 2023

Abstract
Brain tumors are the leading cause of cancer-related death in children. An important hurdle to scientific and clinical progress in the field has been the limited availability of preclinical tumor models. In recent years, the Children’s Brain Tumor Network (CBTN) has accelerated the development of patient-derived cell lines and xenografts, offering these resources to the community through open-source access. While these models are extremely valuable, their development process can be lengthy and result in clonally selected lines which presents a challenge for studying complex tumor biology. To address the need for three-dimensional tissue culture, our group in conjunction with CBTN, generates organoids from fresh tissue specimens obtained directly from surgical resection. This effort resulted in numerous organoid models generated for high-grade glioma (HGG), medulloblastoma, ependymoma, atypical teratoid-rhabdoid tumor, and low-grade glioma tumors. The tissue was processed within an hour post-extraction and cultured in growth factor-free media. Organoid formation and growth were observed as early as in 2 weeks post initiation and continued for up to three months. Banked organoids established growth upon return to culture and resembled similar cell composition to those in the original culture. This provides an excellent preclinical testing model for precision medicine-driven trials. To represent this, we utilized CAR-T testing approach and treated GD2-positive HGG organoids with GD2 CAR-T cells and control CD19 CAR-T cells. 72h exposure to GD2 CAR-T induced morphological changes and significant increase in dead cells within organoids, which was not observed in CD19 CAR-T treated counterparts (p&lt;0.05). Here we provide a simple and efficient workflow for the generation and testing of three-dimensional tumor organoid models generated from fresh surgical tissue. The platform can accelerate not only tumor biology explorations but also empower a diverse array of precision medicine-driven testing for pediatric brain tumors.
CNSC-02. INVESTIGATING THE ROLE OF THE WNT SIGNALING TRANSDUCTION PATHWAY IN GLIOMA BLOOD-BRAIN-BARRIER INTEGRITY
Authors: Tang Kayen , Conrad Christina , Lim Sanghee , Kwak Minhye , Cesaire Melissa , Jackson Sadhana 
Published: June 2023

Abstract
The WNT signaling transduction pathway has been linked to cancer stem cell self-renewal, differentiation, and blood brain barrier (BBB) development. Previous studies have shown that WNT pathway inhibition increased BBB permeability, specifically in WNT medulloblastoma. Glioblastoma, an aggressive malignant tumor with poor prognosis, has also been shown to have high WNT expression and variable BBB permeability. We hypothesize that activating WNT pathway inhibition in glioblastoma stem cells (GSCs) will inhibit glioma progression, increase BBB permeability within the tumor microenvironment, and enhance overall treatment responsiveness. We transduced primary pediatric derived glioma stem cells with overexpressing vectors for WNT inhibitors (DKK1 or WIF1). To characterize effects of DKK1 or WIF1 overexpression, we evaluated cell migration patterns via RTCA xCelligence, cell cycle progression via Annexin 5 assays, and cell viability via cell-titer glo. Brain endothelial cell integrity was evaluated with the treatment of CHIR99021, WNT pathway activator, or GSC condition media with immunoblotting for junctional protein expression (Claudin-5, Claudin-3, Occludin, ZO-1, VE-Cadherin). Verification of WNT inhibitory overexpressing GSCs for DKK1 and WIF1 was performed using RNAseq, proteomics, and immunoblotting. DKK1-GSCs demonstrated a statistically significant impairment in the migratory slope compared to empty vector GSCs. Cell cycle analysis also revealed that DKK1-GSCs were arrested in G0/1 phase while WIF1-GSCs were arrested in S/G2M phase. CHIR99021 endothelial treatment resulted in increased secretion of WNT inhibitors DKK1 and SFRP1 and resultantly, there was a decrease in junctional protein expression. Overall, WNT inhibitor overexpressing GSCs exhibited unique cellular patterns and indirectly disrupted endothelial cell integrity. Future studies will evaluate orthotopic WNT inhibitor overexpressing transplant rodent models to determine BBB integrity, drug permeability, model survival, and chemotherapeutic treatment response. By enhancing our understanding of the WNT pathway in GSCs, we anticipate understanding the use of future therapeutic WNT pathway targeting to increase chemotherapeutic responsiveness and improve glioblastoma prognosis.
CNSC-03. EXPLORING STRUCTURAL DISRUPTION OF TRICELLULAR JUNCTIONS TO ENHANCE BLOOD-BRAIN-BARRIER PERMEABILITY
Authors: Cesaire Melissa , Dalmage Mahalia , Lim Sanghee , Minhye Kwak , Tang Kayen , Conrad Christina , Karim Baktiar , Butcher Donna , Jackson Sadhana 
Published: June 2023

Abstract
The blood-brain barrier (BBB) hinders CNS chemotherapy entry for malignant glioma treatment. It is predominantly composed of brain endothelium linked by bicellular (BJ) and tricellular (TJ) tight junctions. Previous studies demonstrated,angubindin-1 inhibited TJ angulin-1 to increase brain and CSF targeted therapy in rodent lung cancer models. We hypothesize angubindin-1 can transiently decrease BBB junctional integrity to increase chemotherapy permeability and prolong rodent glioma model survival. Rat brain endothelial cells were treated with TJ and BJ inhibitors against angulin-1 (angubindin-1 600µg/mL), claudin-3 (C-CPE 200µg/mL) or claudin-5 (C-CPE-MT 200µg/mL). Endothelial integrity was assessed by immunoblotting and cell-cell electrical impedance. Effects of angubindin-1 on efflux transporter P-glycoprotein (PGP) and migration were studied using rat and human derived glioma cells. Rat glioma models were treated with doxil (3 mg/kg), angubindin-1 (10 mg/kg or 30 mg/kg), or combination therapy for assessments on tumor volume, BBB permeability and survival. We observed decreased angulin-1 expression 5 hours after angubindin-1 treatment, with return to baseline by 24 hours (p&lt;0.05). Angubindin-1, CCPE, and CCPE-mt globally reduced endothelial cell-cell integrity, maximally at 4 hours with a return to baseline by 12 hours; with angubindin-1 demonstrating the largest decreased cell-adhesion (angubindin-1 vs control, p&lt; 0.0001). Angubindin-1 also decreased PGP efflux of rhodamine in both endothelial and glioma cells, along with demonstrating a pro-migratory dose-dependent effect on rat glioma cells. Combined angubindin-1 and doxil increased survival in rat glioma models compared with doxil alone (24 days vs. 18 days, p &lt; 0.0001). Day 14 tumor volume was significantly decreased with angubindin-1 and combination treatment respectively (77.5 % vs 81.6 %, p&lt;0.05). Ongoing studies are exploring, angubindin-1’s effect on large CNS drug permeability, TJ localization post BBB disruption and additional combinational treatments in glioma models. Collectively, these findings pose a unique opportunity to disrupt BBB integrity and improve malignant glioma treatment options.
CNSC-04. EVALUATING LONGITUDINAL WORKING MEMORY PERFORMANCE IN PEDIATRIC PATIENTS WITH CRANIOPHARYNGIOMA VIA FMRI
Authors: Chang Chih-Chiang , Zou Ping , Scoggins Matthew A , Conklin Heather , Hua Chia-Ho , Merchant Thomas E , Sitaram Ranganatha 
Published: June 2023

Abstract
Craniopharyngioma is a type of benign brain tumor that develops in the suprasellar region of the brain and can lead to long-term neurological, endocrine, and visual impairments as well as neurocognitive deficits resulting from the tumor and its treatment. The contemporary treatment options for this tumor are radical surgery or limited surgery in conjunction with radiotherapy. The current understanding of the impact of brain injury related to the tumor and its treatment such as proton radiotherapy (PRT) on neurocognitive function is limited.
The study (NCT01419067) was approved by the IRB and informed consent was obtained from patients or their parents. Functional magnetic resonance imaging (fMRI) was performed in a 3T MRI imaging system (Siemens MAGNETOM Prisma, Erlangen, Germany) and used to evaluate the neurocognitive performance of 58 pediatric patients (31 females and 27 males) before and after proton radiotherapy (PRT). The patients underwent serial imaging at four-time points (baseline, 18, 36, and 60 months after PRT) and performed a working memory (0-back, 1-back, and 2-back) task-based fMRI. A full factorial model was used for longitudinal group analysis at different time points through statistical parametric mapping. Omission errors, commission errors, and reaction time were measured for each task.
The results showed robust detection of the working memory network with increased activation (FDR&lt;0.05) in the precuneus, mid-temporal gyrus, and angular gyrus at 36 months compared to 18 months. The behavioral test results showed a gradual decrease in omission errors in the 2-back task group and an increase in reaction time for all three task groups over time.
These findings suggest that PRT has a transient effect on brain activation and behavioral performance, potentially indicating improved executive functioning, recovery from the mass effect of the tumor and/or surgery, and the minimal negative impact from PRT.
DIPG-03. IDENTIFICATION OF NEW THERAPEUTIC TARGETS BY ARRAYED CRISPRA-BASED APPROACH TO MAP RADIORESISTANCE IN DMG
Authors: Fernandez Solène , Laternser Sandra , Sellitto Stefano , Neupane Sandesh , Petrovic Antonela , Ciani Ludovica , Kritzer Bettina , Hasler Kerstin , Bamert David , Nazarian Javad , Aguzzi Adriano 
Published: June 2023

Abstract
Pediatric Diffuse Midline Glioma (DMG) is amongst the most aggressive childhood brain tumors. The dismal prognosis is less than a year for children diagnosed. Radiotherapy (RT) remains the only standard treatment that provides only transient relief of clinical symptoms of DMG patients. Poor survival is associated with radio-resistance due in part to P53 mutational status and to invasive tumor properties related to epigenetic dysregulation. Over 80% of DMG patients harbor oncohistone 3 mutations (H3K27M) leading to global genome hypomethylation and transcriptional disruption. Transcriptional factors are known as master regulators of the genome but their implication in response to radiation treatment remains unclear.
We developed an arrayed-CRISPR screen strategy to understand the role of transcription factors in radioresistance mechanisms in DMG-patient-derived cells.
We performed arrayed-CRISPRa screening in multiwell plates with DMG cells expressing the dCas9-VP64, infected with gRNA lentiviral library to target each transcription factor (one transcription factor overexpressed per well). Each plate was irradiated fractionally (2Gy/day) and after irradiation stopped a comparison between cells overexpressing one targeted transcription to internal controls (non-targeted-gRNA infected cells) has been conducted. Transcription factor “hits” identification is based on Log2FC (logarithm 2 fold-change) with a value higher than 0.6, considering these targets as potentially involved in DMG cell radio-resistance and/or proliferation mechanisms. We identified 82 “hits” with more than 30% described as involved in radio-resistance mechanisms and/or tumorigenesis process, sustaining our screen results. We focus on “hits” with a Log2FC higher than 1 to identify the most robust targets playing a role in resistance to radiation. Currently, DMG cells are being treated with RT combination with pharmacological inhibitors to validate our candidate target involvement in DMG radio-resistance. Our goal is to achieve a better understanding of resistance mechanisms to identify therapeutic treatments to combine with radiotherapy to overcome radio-resistance developed by DMG cells.
DIPG-11. DISSECTING THE DIFFUSE MIDLINE GLIOMA TUMOR MICROENVIRONMENT COMMUNICATIONS USING MULTI-OMICS APPROACHES
Authors: Collot Raphael , Moreno Cristian Ruiz , Wezenaar Amber , Zomer Anoek , Johnson Hannah , Stunnenberg Henk , Rios Anne 
Published: June 2023

Abstract
Diffuse midline glioma (DMG) represents a highly aggressive pediatric brain tumor with no chance of survival. Treatment options are urgently needed, and efforts have been put towards developing T-cell immunotherapy. However, this should consider DMG’s unique tumor microenvironment (TME), both in terms of anatomical location and developmental stage. To gain knowledge on this unique tumor niche, we implemented an immuno-competent, syngeneic mouse model based on in-utero electroporation (IUE) of the key driver mutations to induce tumor formation at an embryonic stage. We characterized DMG’s spatial and molecular landscape by combining snRNAseq, spatial transcriptomics, and state-of-the-art imaging. We observed a high intratumoral heterogeneity with spatially restricted cell populations. Importantly, their molecular profiles correlate with patient data, illustrating the clinical relevance of the IUE model. Analysis of cell-cell communications in the TME revealed novel signaling between DMG and immunosuppressive myeloid cells that could impact T-cell response. Using an advanced patient-derived DMG organoid co-culture model with macrophages and engineered T-cells, we are currently investigating the role of this pathway on T-cells mediated killing of DMG organoids. Thus, this project fills a critical need to delineate and overcome the immune-suppressive environment in DMG and potentiate T cell targeting.