bluuebunny/crossref_metadata_2025_split huggingface dataset:
TMET-37. SODIUM-DEPENDENT GLUCOSE TRANSPORTER 2 (SGLT2) IS OVEREXPRESSED IN THE MAJORITY OF ATRTS AND A SUBSET OF PEDIATRIC PATIENTS WITH HIGH-GRADE GLIOMA; A POTENTIAL IMAGING AND THERAPEUTIC TARGET
Authors: Nabavizadeh Ali , Zhao Chao , Martinez Daniel , Familiar Ariana , Koptyra Mateusz , Ippolito Joseph , Rubin Joshua , Storm Philip B , Resnick Adam C , Santi Mariarita 
Published: November 2022

Abstract
Sodium glucose cotransporters (SGLT) are a class of glucose transporters independent of the conventional glucose transporters (GLUT). Like the GLUT, SGLT2 plays an important role in glucose uptake in many solid cancers. Importantly, SGLT2 inhibitors are a new class of anti-diabetic drugs and have recently been investigated as a potential anti-cancer therapy in a variety of solid cancers. In fact, a recent study in adult high-grade gliomas showed that an SGLT-specific PET imaging probe ([18F] Me-4FDG) is sensitive for visualization of high-grade glioma (HGG) with superior tumor-normal brain uptake relative to 18F-FDG-PET. We aimed to investigate the expression of SGLT2 within pediatric brain tumor subtypes using RNA sequencing data from PedcBioPortal and immunohistochemistry of tissue microarrays (TMAs). Using the RNA sequencing data from 603 patients with pediatric brain tumors, we found that HGGs have the highest SGLT2 expression (Z score=0.13± 1.03) and were significantly higher compared to low-grade gliomas (Z score= -0.12, p=0.049), medulloblastomas (Z score=-0.28, p=0.001), and ependymomas (Z score=-0.30, p=0.002). Atypical teratoid rhabdoid tumors (ATRT) also had significantly higher Z score (0.10±0.67) compared to medulloblastomas (p=0.038), and ependymomas (p=0.049). There was no significant difference between HGGs and ATRTs in SGLT2 expression (p=0.899). Analysis of 4 TMAs including HGGs, medulloblastomas, ependymomas, and ATRTs after SGLT2 immunohistochemistry demonstrated strong membranous staining in a small subset and moderate-weak staining in the majority of HGGs. The majority of ATRTs were positive. The majority of medulloblastomas and ependymomas were negative, noting that the membranous nature of the staining may be a limiting factor in evaluation of tumors with less cytoplasm. In conclusion, our work demonstrates that SGLT2 has heterogeneous expression in pediatric brain tumors and is overexpressed in the majority of ATRTs, and a subset of pediatric HGGs, and may represent a compelling paradigm that integrates metabolic imaging and therapy of these tumors.
TMIC-12. COMPLEMENT SIGNALING IN HYPOXIC NICHES OF THE GLIOMA MICROENVIRONMENT
Authors: Rosberg Rebecca , Smolag Karolina , Sjölund Jonas , Pantazopoulou Vasiliki , Pietras Kristian , Blom Anna , Pietras Alexander 
Published: November 2022

Abstract
Glioblastoma is the most common and aggressive primary brain tumor in adults. Despite treatment through surgery, irradiation and chemotherapy, all patients suffer recurrence of treatment-resistant tumors. Previous studies from our lab showed that astrocytes become reactive and generate tumor-supportive conditions for glioma cells, when exposed to hypoxia or irradiation. Reactive astrocytes are known to upregulate proteins of the complement system, especially complement component 3 (C3), in several neurological disorders. However, it remains unexplored how these complement proteins are expressed in stromal astrocytes in glioblastoma. Tissue sections from a glioma mouse model showed presence of C3 in the invasive front, and in hypoxic, and perivascular spaces of the tumors, where there is an abundance of astrocytes. C3 expression co-localized with Nestin and CD44, two markers of mesenchymal and/or stem-like glioma cells. Primary human astrocytes grown in hypoxic conditions upregulated C3 as well as other proteins associated with a more extensive infiltrative phenotype of glioblastoma. In general, a strong correlation between hypoxia (195 genes) and complement (200 genes) gene signatures were found in TCGA GBM dataset (R= 0.82, p-value= 0). Single-cell sequencing data from primary GBM tumors showed a subpopulation of highly C3-expressing astrocytes, which were enriched for cellular pathways comprising epithelial mesenchymal transition (EMT), TNF-alpha, complement, hypoxia, and interferon signaling. Human glioma cell lines from proneural, classical and mesenchymal subtypes all showed increased CAIX and GLUT1 expression grown under lower oxygen tensions, while two out of three subtypes showed upregulation of stemness markers (OCT4 and NANOG1) as well as C3 and C3aR. Overall, our data indicate a strong link between hypoxia and complement expression in the brain tumor microenvironment, where a local expression of complement proteins could possibly lead to tumor promoting signaling, which will be further explored.
TMIC-13. GLIOMA-DRIVEN DENDRITIC CELL DYSFUNCTION AS AN IMMUNE EVASION STRATEGY AGAINST ADOPTIVE CELLULAR THERAPY
Authors: Jin Dan , Dean Bayli DiVita , Francis Connor , Font Laura Falceto , Reid Alexandra , Figg John , Sebastian Mathew , Flores Catherine 
Published: November 2022

Abstract

BACKGROUND
Our previous studies has developed an adoptive cellular therapy (ACT) against high grade gliomas in both human and murine systems. ACT significantly improves survival in murine models of CNS malignancies. Our studies have shown that efficacy is associated with the observed increase in tumor-associated dendritic cells (DC) which arise from transferred hematopoietic stem cells (HSC). HSC-derived DCs play a pivotal role in mounting the anti-tumor immune response. In this study, we have identified that treatment resistance may be due to glioma-driven dendritic cell dysfunction. We observed significant down regulation of co-stimulatory markers on tumor-associated dendritic cells in mice that escaped ACT and subsequent capacity to activate tumor-reactive T cells.Method: KR158B bearing mice received HSC and tumor reactive T cells one day before 9 Gy irradiation followed by 3 does of BMDC vaccine. Tumor associated DCs were sorted from tumors evaded from ACT and co-cultured with primary KR158B reactive T cells or escaped KR158B reactive T cells. T cell proliferation and interferon gamma were detected for comparison. PCR array was performed to identify dysregulated functional genes.Results and

CONCLUSIONS
Functional evidence demonstrated that dendritic cells from resistant tumor had significantly decreased capacity in activating tumor-reactive T cells against either primary KR158B glioma cells or T cells generated to target tumor cells that evaded ACT. Gene expression data showed this may be due to significant decreases in genes associated with co-stimulation, T cell engagement, and antigen presentation.
TMIC-19. NEURODEVELOPMENTAL SUBTYPES SHAPE LIPID METABOLIC REPROGRAMMING IN GLIOMAS
Authors: Minami Jenna , Bayley Nicholas , Tse Christopher , Zhu Henan , Salinas Jennifer , Morrow Danielle , Yong William , Cloughesy Timothy , Liau Linda M , Graeber Thomas G , Nathanson David 
Published: November 2022

Abstract
Gliomas have been classified into molecular (proneural, classical, mesenchymal) and neurodevelopmental (astrocyte, mesenchymal, neural progenitor cell (NPC), oligodendrocyte progenitor cell (OPC)) subtypes describing inter- and intra-tumoral heterogeneity; however, the functional outcomes and therapeutic implications of these subtypes has yet to be fully described. Metabolic reprogramming is a hallmark of cancer, and malignant cells, including gliomas, acquire metabolic adaptations in response to a multitude of intrinsic (oncogenotype, mutations) and extrinsic (tumor microenvironment) factors to fuel neoplastic progression. Altered metabolism in glioma is of particular interest given the extensive molecular heterogeneity of tumors, while also developing in the brain microenvironment, a tissue known for its unique metabolic milieu. It is unknown whether neurodevelopmental subtypes influence metabolism in gliomas. Preliminary comprehensive lipidomic and transcriptomic analysis of over 200 patient-derived glioma samples revealed that distinct lipid signatures were linked to neurodevelopmental subtypes. Specifically, proneural-like gliomas (OPC, NPC, Neuron) had a lipid metabolic profile enriched in ether lipids. Conversely, mesenchymal-like gliomas (radial glia, MES.progenitor, vascular) have a lipid metabolic profile enriched in triacylglycerides (TAGs). Intriguingly, these differences in lipid metabolic programs between subtypes were associated with environmental dependencies; in contrast to more mesenchymal like gliomas, which could grow irrespective of tumor microenvironment (brain or in vitro cell culture), the proneural-like gliomas required features of the brain microenvironment to accumulate complex fatty acids and grow. Collectively, these data emphasize the metabolic heterogeneity within gliomas, and reveal a subset of gliomas that lack metabolic plasticity in fatty acid biosynthetic programs, indicating a potential brain-microenvironment specific metabolic dependency linked to transcriptional identity that may be targeted for therapy.
TMIC-24. SINGLE-CELL ANALYSIS OF TUMOR-ASSOCIATED MICROGLIA AND MACROPHAGES FROM HUMAN GLIOBLASTOMA
Authors: Anand Atul , Olsen Rikke Frydendahl Sick , Burton Mark , Harwood Dylan Scott Lykke , Poulsen Frantz Rom , Halle Bo , Pedersen Christian Bonde , Kruse Torben , Thomassen Mads , Kristensen Bjarne Winther 
Published: November 2022

Abstract

INTRODUCTION
Patients with glioblastoma have a very poor prognosis. Tumor-associated microglia and macrophages (TAMs) constitute up to 30 % of the cells in glioblastoma, and they secrete cytokines, chemokines and growth factors that influence the microenvironment. The existence of different TAM subtypes appears to be more complex than the established M1 and M2 phenotypes, but their role in glioblastoma is not fully understood and rarely considered therapeutically. This could explain why many clinical trials fail despite of promising preclinical results. This project aims to interrogate the existence and characteristics of different TAM subtypes in human glioblastoma in order to identify novel subpopulations and therapeutic targets. MATERIALS AND

METHODS
Live CD11b+ TAMs were isolated from patient glioblastoma tissue, and single-cell RNA sequencing (scRNA-seq) was performed using the 10X Genomics Chromium platform. The data was processed and analyzed with the R-package Seurat.

RESULTS
We have sequenced 74,000 TAMs/microglia from three glioblastomas and two control brain biopsies. In the controls, we detected mostly microglia, while the primary glioblastomas showed a predominance of monocyte-derived TAMs. We identified 11 TAM subtypes, such as hypoxic, proliferating, interferon-induced, chemokine-producing and TNF-producing TAMs, as well as a novel subtype potentially involved in tumor progression.

CONCLUSION AND PERSPECTIVES
We have detected a spectrum of TAM subtypes, which is more complex than the established M1 and M2 phenotypes. Our findings confirm a recent TAM scRNA-seq study, and in addition, we identify a novel subpopulation, which express known tumor-promoting genes, normally expressed by cancer cells. We are currently validating our findings. This study contributes to the elucidation of the glioblastoma microenvironment. It will potentially lead to identification of novel clinically relevant targets affecting the TAM-glioblastoma interactions.
TMIC-27. SPATIALLY RESOLVED T CELL RECEPTOR SEQUENCING (SPTCR-SEQ) UNCOVERS REGIONAL DIVERSITY OF ANTI-TUMOR IMMUNE RESPONSES
Authors: Benotmane Jasim Kada , Kueckelhaus Jan , Beck Juergen , Schnell Oliver , Heiland Dieter Henrik 
Published: November 2022

Abstract
Regional diversity of anti-tumor immunity in glioblastoma (GBM) has been poorly investigated due to technical limitations. To overcome these hurdles, we developed SPTCR-seq (SPatial TCell Receptor sequencing) to spatially profile T cell immune response. Here, we performed 10X-Visium spatial transcriptomics and SPTCR-seq on 9 de-novo IDH wt glioblastoma. For SPTCR-seq, we captured enriched T-cell receptor (TCR) sequences by hybridization followed by Oxford nanopore (ONT) long-read sequencing. We established a computational pipeline for spatial demultiplexing, error correction and TCR reconstruction using a Seq2Vector model, followed by a long-term memory autoencoder to deconvolute and compare CDR3 sequence similarities across patients. The on-target rate for detected TCR genes reached over 85%, of which our long-TCR algorithm could completely reconstruct TCRs in over 70%. To decipher the regional diversity of T-cell clonality, we performed spatially weighted regression to estimate the overlap of T-cell clonal expansion to the recently described regional transcriptional niches. We found that myeloid cell infiltration was highly correlated with increased T cell diversity. We integrated single cell RNA-seq data and annotated T cell subtypes through the “natural barcode” of the CDR3 sequence, revealing that CD4+ T cells interact with myeloid cells via MHCII in segregated areas, also described as the Reactive Immune niche. In contrast, CD8+ T cells exhibit a dysfunctional/exhausted phenotype at the same location. In comparison to the myeloid-infiltrated regions, the hypoxia-associated niches showed increased CD8+ T cells with greater clonal expansion, suggesting an immune response anti-cancer immunity. Global spatial vector field analysis revealed a spatial co-occurrence of metabolic vulnerability and a mutational burden with CD8+ T effector cells negatively associated with myeloid cell infiltration. Integration of CDR3 sequences in different patients revealed higher similarity of motifs of CD4+ compared with CD8+ T cells in hypoxia areas. Our data provide new insights into the regional heterogeneity of cancer immunity.
TMIC-29. CHARACTERIZING THE ROLE OF TRIGGERING RECEPTOR EXPRESSED ON MYELOID CELLS 2 (TREM2)-EXPRESSING MICROGLIA/MACROPHAGES IN GLIOBLASTOMA
Authors: Peshoff Mekenzie , Gupta Pravesh , Oberai Shivangi , Milam Nancy , Ahmed Aml , Dang Minghao , Wang Linghua , Bhat Krishna 
Published: November 2022

Abstract
The tumor microenvironment in glioblastoma (GBM) contains numerous cell types, notably a rich immune compartment dominated by myeloid cells, such as brain-resident microglia and infiltrating macrophages. However, current immunotherapies target lymphoid components like T cells, which are sparse in the brain and the tumors originating there. Therefore, immune checkpoint drugs designed for systemic cancers have not yielded significant benefits for patients with glioblastoma, and the efficacy of immunotherapy for central nervous system malignancies lags behind treatments for other solid tumors. Further understanding of the myeloid compartment is necessary for developing glioblastoma immunotherapies. Our recent single cell RNA-seq (scRNA-seq) analyses have identified microglial clusters that are enriched for antigen presentation and phagocytic gene expression modules. These clusters were restricted to microglia and macrophages seen only in glioma patients, but not in myeloid cells derived from non-glioma brain controls. Triggering receptor expressed on myeloid cells 2 (TREM2), a receptor abundant on microglia and vital for the detection and phagocytosis of pathogens, was highly expressed in these clusters. Because microglia expressing TREM2 play a protective role in neurodegenerative diseases like Alzheimer's disease, we examined the function of TREM2+ myeloid cells in GBM using mice lacking TREM2. Implantation of GL261 cells in TREM2-/- mice showed significantly reduced survival relative to wild-type mice, suggesting a protective role of TREM2+ myeloid cells in glioma. Data on immunophenotyping of glioma xenografts from WT and TREM2-/- mice brains using state of the art technologies (e.g. Cytek) will be presented. We conclude that TREM2 is a phagocytic immunoregulator in glioblastoma, manifesting anti-glioma properties to TREM2+ myeloid cells.
TMIC-36. REPROGRAMMING THE GLIOBLASTOMA IMMUNE MICROENVIRONMENT WITH CONVECTION ENHANCED GENE THERAPY REVEALS INTRATUMOR IL6 DRIVES GLIOBLASTOMA IMMUNOSUPPRESSION AND GROWTH
Authors: Young Jacob S , Cho Nam Woo , Lucas Calixto-Hope , Seo Kyounghee , Santos Raquel , Liu S John , Phillips Joanna J , Ozawa Tomoko , Bhaduri Aparna , Aghi Manish , Berger Mitchel S , Raleigh David 
Published: November 2022

Abstract
The glioblastoma microenvironment is an immunosuppressive barrier to therapeutic innovation. We hypothesized intratumor convection enhanced delivery (CED) of gene therapy vectors could reprogram the glioblastoma immune microenvironment and elucidate therapeutic vulnerabilities. To test this, SB28 or GL261 glioblastoma allografts were implanted into immunocompetent mice and treated with CED of attenuated adeno-associated virus 9 vectors (AAV9) encoding experimental cytokines (Il1b, Ccl4, or Apoa1) underlying infiltration or activation of anti-tumor immune cells in other intracranial tumors. Serial intracranial bioluminescence was used to assess glioblastoma growth and animals were monitored for survival. The impact of gene therapy perturbations on the glioblastoma immune microenvironment was assessed using histology, immunohistochemistry, single-cell mass cytometry (CyTOF), and multiplexed cytokine assays. Serial body weight and systemic cytokine measurements showed no evidence of treatment toxicity. AAV9-APOA1 or AAV9-IL1B gene therapy CED treatments attenuated SB28 growth and prolonged survival, decreasing immunosuppressive macrophage infiltration and increasing CD8 T cell and microglia infiltration of the glioblastoma microenvironment compared to control AAV9 vectors. Gene therapy CED treatments did not attenuate GL261 growth or prolong survival, but CyTOF of human glioblastomas (n=6) in comparison to preclinical models revealed untreated GL261 glioblastomas were endogenously enriched in CD8 T cells and other lymphoid lineages compared to untreated SB28 or human glioblastomas. Multiplexed cytokine assays demonstrated suppression of intratumor IL6 is a conserved mechanism of action underlying glioblastoma gene therapy responses. Single-cell RNA sequencing analysis of 32,877 cells from human glioblastomas (n=11) showed IL6 is predominantly produced by radial glial like cancer stem cells or endothelial cells in the tumor microenvironment. In support of these findings, survival from intracranial SB28 glioblastomas was prolonged in Il6 knockout C57BL/6J mice compared to wildtype mice. In summary, we report a novel strategy using gene therapy and CED to reprogram the glioblastoma immune microenvironment, revealing IL6 drives glioblastoma immunosuppression and growth.
TMIC-38. CD39 EXPRESSION IN GLIOBLASTOMA TUMOR MICROENVIRONMENT DOES NOT AFFECT SURVIVAL OR T-CELL EXHAUSTION
Authors: Zheng Allison , Pappu Ananya , Gill Sabraj , Stelter Isabella , Aghi Manish 
Published: November 2022

Abstract
Glioblastoma (GBM) is the most common malignant brain tumor with a median survival of 15 months. GBM is very difficult to treat due to numerous factors, including the paucity of immune infiltration of the tumor itself. Efforts to overcome this have led to use of immune checkpoint inhibitors such as PD-1 inhibitor, which have revolutionized treatment of many other solid tumors, and yet have not been successful in the treatment of GBM. This has led to many studies investigating various other similar markers. One such marker is CD39, which is highly upregulated in GBM and functions as the first enzyme in the metabolic pathway of ATP breakdown to adenosine. Additionally, CD39 is thought to contribute to T-cell exhaustion. Like PD-1, CD39 inhibition has had preliminary success in the treatment of other solid tumors. However, when tested on GBM, blocking the ATP breakdown pathway did not improve survival in mice, even in conjunction with PD-1 inhibition. Our team sought to determine if the expression of CD39 on the cell surface functioned as an exhaustion marker by injecting two different cell lines of GBM into CD39 global null mice. There was no survival benefit seen in either cell line when compared to wild type mice. Next, expression of known exhaustion markers such as PD-1, TIM3, and LAG3 on tumor infiltrating lymphocytes were analyzed. Expression of TIM3 and 2B4 were found to be increased in CD39KO mice in comparison to wild type (p &lt; 0.01). Additionally, numerous exhaustion markers such as LAG3, TIGIT, and CTLA4 were decreased on tumor in comparison to peripheral blood (p &lt; 0.01). These results demonstrate the complex nature of immune signaling in GBM tumor microenvironment that our team continues to investigate.
TMIC-41. ARGININE DEPRIVATION ALTERS DNA DAMAGE RESPONSE IN ARGINOSUCCINATE SYNTHETASE NEGATIVE GLIOBLASTOMA AND POTENTIATES STANDARD OF CARE
Authors: Ghosh Avik , Perryman Richard , O'Neill Kevin , Syed Nelofer 
Published: November 2022

Abstract
Glioblastoma (GBM) is the most aggressive and prevalent primary brain malignancy with an average life expectancy of 18 months despite the standard of care which includes resection, temozolomide and radiotherapy. Thirty percent of GBMs show transcriptional loss of arginosuccinate synthetase 1 (ASS1), displaying arginine auxotrophy and hence, are amenable to arginine deprivation therapy by ADI-PEG20. Moreover, these tumours are more aggressive than their non-arginine auxotrophic counterparts. In this study we demonstrate that this may lie in part due to their enhanced ability to repair damaged DNA. ADI-PEG20 significantly altered the expression of DNA repair genes in vitro and in vivo. We observed downregulation of PCNA, ATR (p=0.0063) and CHEK1 (p=0.0150) and upregulation of CHEK2 (p=0.0033) and RAD51 (p=0.0230). PARP1 was also downregulated, albeit not statistically significant. Addition of ADI-PEG20 to temozolomide and radiation also caused significant downregulation of BRCA1 (p=0.0340) . With DNA repair gene upregulation contributing to treatment resistance and DDR inhibitors shown to potentiate current therapies in the literature, not only do our results help elucidate the mechanisms of radiosensitisation with ADI-PEG20, targeting this pathway with DDR inhibitors alongside the pleiotropic effects of ADI-PEG20 may provide a novel therapeutic combination for ASS1 negative GBM.