bluuebunny/crossref_metadata_2025_split huggingface dataset:
CNSC-29. INVESTIGATING THE INFLUENCE OF DOPAMINERGIC ACTIVITY ON THE GLIOBLASTOMA NICHE
Authors: Ware Matthaeus , Pontual Luiza Lopes , Yu Chunying , Kushida Michelle , Rastegar Naghmeh , Dolma Sonam , Dirks Peter 
Published: November 2022

Abstract
Glioblastoma (GBM) is an incurable disease of adults and children and the deadliest form of central nervous system (CNS) malignancy. Despite major advances in our understanding of GBM biology in recent years, the prognosis for patients who develop this disease has not improved. If we hope to find new treatments for GBM that are safe and effective, we desperately need to reform our thinking. The brain’s chemical milieu is rich with neurotransmitters, and our lab’s screen of 680 neuroactive compounds on patient-derived glioblastoma stem cells (GSCs) in vitro strongly implicates neurotransmitter pathways as critical regulators of the GSC niche. More specifically, disrupting dopamine signaling by inhibiting its receptor D4 on GSCs causes substantial GSC apoptosis in vitro and attenuates GBM growth in vivo (Dolma et al., Cancer Cell, 2016). Dopamine (DA) is a catecholamine neurotransmitter that is essential for reward learning and movement and has numerous roles in cognition. Consequentially, dysregulation of DA signaling is associated with a diversity of brain diseases ranging from drug addiction to schizophrenia to Parkinson’s. Our research aims to determine how DA signaling affects normal neural stem cell (NSC) and tumorigenic GSC populations, as we hypothesize that GSCs arising/residing in DA projection zones exploit dopaminergic (DAergic) activity for GBM growth. Toward these aims, we have developed in vivo model systems and harnessed them to study NSC and GSC niches in the context of either controlled activation or depletion of DAergic neurons. These manipulations of the brain's DAergic neurons are achieved using optogenetic stimulation, genetic depletion, and neurotoxin-mediated ablation in mice. Ultimately, unraveling the dopaminergic influence on GBM may contribute to a redeployment of existing treatments—that modulate DA signaling and are already approved to treat CNS disorders—to patients with this deadly brain cancer.
TMIC-56. TUMOR CELL ARCHITECTURAL HETEROGENEITY AND SPATIAL INTERACTIONS WITH THE TUMOR IMMUNE MICROENVIRONMENT IN GBM
Authors: Silver Aryeh , Feier Diana , Tian Guimei , Andrews Michael , Dajac Mariana , Yang Changlin , Ghosh Tanya , Fu Dongtao , Von Roemeling Christina , Rahman Maryam , Sarkisian Matthew , Huang Jianping , Harrison Jeffrey , Mitchell Duane , Deleyrolle Loic 
Published: November 2022

Abstract

INTRODUCTION
Glioblastoma (GBM) contains cell populations with distinct metabolic requirements, with fast-cycling cells harnessing aerobic glycolysis, and treatment-resistant slow-cycling cells (SCCs) preferentially engaging lipid metabolism. The interaction between immune and tumor cells, and how their metabolic heterogeneity shapes the immune landscape in GBM has yet to be understood. Objectives: The primary objective of this project is to spatially and molecularly decode the GBM microenvironment heterogeneity with a specific focus on unraveling the metabolic links that underlie the interaction of SCCs with the immune compartment.

METHODS
Multiple murine glioma cell lines coupled with geospatial profiling were used to establish metabolic heterogeneity and communications, while various genetic and pharmacological approaches were applied to assess the effect of disrupting the metabolic interplay between SCCs and the immune system.

RESULTS
We determined that SCCs exhibit distinct metabolic dependencies, involving preferential lipid metabolism supported by enhanced fatty acid uptake. We also found that SCCs exhibit specific geospatial distribution and that tumor progression is regulated by their interactions with immune suppressive cells, which in turn work against tumor immune rejection by inhibiting T cell anti-tumor activity. The immune microenvironment shaped by SCCs is marked by specific metabolic features enhancing lipid exchange capacities that are exploited by SCCs to support their survival and functions. Importantly, disrupting lipid metabolic exchange sensitized tumors to chemotherapy.

CONCLUSION
Our results reveal that metabolic interactions between SCCs and tumor-associated immune suppressive cells within the GBM microenvironment play a critical role in the development of drug and immune resistant tumors. This study delineates these metabolic communications and assesses the potential therapeutic effect of disrupting these interactions to treat GBM. The insights generated from this project uncover fundamental principles of the emerging connections between the tumor microenvironment, cell metabolism, anti-tumor immunity, and associated therapeutic vulnerabilities.
TMIC-60. THE ROLE OF ICAM1 IN GLIOBLASTOMA TUMORIGENESIS UNDER HYPOXIC CONDITIONS
Authors: Devaraja Kaviya , Singh Olivia , Mansouri Sheila , Ali Hafsah , Zadeh Gelareh 
Published: November 2022

Abstract
Glioblastoma (GBM) is a fatal brain cancer in adults with ineffective existing treatment methods. Cell adhesion molecules (CAMs) are proteins that are expressed on the surface of cells and enable them to interact with one another and the surrounding microenvironment. Intracellular adhesion molecule 1 (ICAM-1) is a cell adhesion molecule expressed by macrophages, tumor cells and endothelial cells in GBM. Preliminary data showed that ICAM-1 is associated with poorer overall and progression free survival in GBM patients and ICAM-1 expression levels increase in recurrent GBM tumors. TAMs enhance tumor growth and proliferation, within GBM. The goal of this study was to determine whether and how ICAM-1 expression on TAMs contributes to GBM tumorigenesis, specifically within the hypoxic tumor microenvironment. We hypothesized that ICAM1 facilitates TAM migration, proliferation and phagocytosis, thus enhancing tumor growth. We found that upon incubation of human and mouse primary macrophages in hypoxia, ICAM-1 expression levels increased and were further exasperated upon culturing with tumor cell-conditioned medium. Incubation of ICAM-1 deficient macrophages in hypoxia resulted in lower migration and proliferation in ICAM-1 deficient cells compared to wild type cells. When cultured with tumor cell condition media, migration and proliferation of ICAM-1 deficient macrophages was lower than wild type macrophages. Further, intracranial injection of tumor cells into ICAM-1 deficient and wild type mice revealed that ICAM1 deficient mice survived longer and had lower overall tumor volume than wild type mice. In conclusion, the expression of ICAM1 in TAMs likely promotes GBM tumorigenesis by enhancing their proliferation and migration into the tumor microenvironment. ICAM-1 plays a role in macrophage migration, proliferation, and its expression on TAMs, resulting in more aggressive and invasive tumors. In addition, certain environmental factors like hypoxia further enhance the expression of ICAM-1 in macrophages which is associated with more aggressive features of GBM.
TMIC-61. LOSARTAN PREVENTS IMMUNOTHERAPY-ASSOCIATED EDEMA AND ENHANCES SURVIVAL IN GLIOBLASTOMA
Authors: Datta Meenal , Chatterjee Sampurna , Perez Elizabeth , Gritsch Simon , Roberge Sylvie , Duquette Mark , Chen Ivy , Naxerova Kamila , Kumar Ashwin , Ghosh Mitrajit , Emblem Kyrre , Ng Rosa , Ho William , Kumar Pragya , Krishnan Shanmugarajan , Dong Xinyue , Speranza Maria , Neagu Martha , Reardon David A , Sharpe Arlene , Freeman Gordon , Suva Mario , Xu Lei , Jain Rakesh 
Published: November 2022

Abstract
Immune checkpoint blockers (ICBs) have revolutionized the treatment of some solid cancers but have failed to benefit the majority of glioblastoma (GBM) patients. Two reasons underlying limited ICB benefit are: 1) immune-related adverse events, and 2) resistance conferred by the tumor microenvironment. Here, we show that ICBs induce cerebral edema in patients and GBM mouse models. This edema results from an inflammatory response to ICB treatment that disrupts the blood-tumor-barrier, as confirmed by intravital imaging, mechanistic blocking studies, and single-cell RNA sequencing. Losartan – a commonly prescribed antihypertensive agent – controls ICB-induced edema, reprograms the immunosuppressive tumor microenvironment, and improves survival under ICB therapy. In combination with a standard of care regimen in mice mimicking clinical treatment (surgical resection, chemoradiation), losartan increases the percent of long-term surviving (cured) mice under ICB therapy from 16% to 43%. Finally, a bihemispheric “resect-and-response” model to establish predictive biomarkers from the tumor microenvironment reveals that cured mice have an immunostimulatory (“hot”) immune tumor compartment prior to therapy. These results provide the basis for clinical testing of adding to losartan to ICB treatment for GBM patients.
TMIC-63. SELECTIVE TARGETING OF IMMUNE-SUPPRESSIVE LEUKOCYTES TO REPROGRAM THE GBM IMMUNE LANDSCAPE
Authors: Abdelfattah Nourhan , Maldonado Jose , Liu Jia-Shiun , Tran Nhat , Yun Kyuson 
Published: November 2022

Abstract
A significant barrier to immunotherapy efficacy is GBM’s immunosuppressive microenvironment composed of few tumor-infiltrating lymphocytes (TILs; &lt; 5%) but abundant myeloid cells, making it an “immune cold” tumor. To enhance immunotherapy efficacy, a better molecular and functional understanding of the heterogeneous cell types in the GBM microenvironment and their function is urgently needed. Single cell RNA-sequencing offers high-resolution cellular and molecular data to elucidate cancer and stromal cell phenotypes at the single cell level to identify the most relevant cell types to target to enhance immune activation. We recently reported an integrated, multi-regional and -dimensional single-cell transcriptomic analysis of 201,986 human glioma and immune cells derived from 44 tissue fragments from 18 human glioma patients. In doing so, we mapped GBM cellular heterotypia and spatial, molecular, and functional heterogeneity of glioma associated immune cells. We observed an extensive spatial and molecular heterogeneity of glioma cells, microglia, macrophages, and T cells within the same tumor samples in low-grade gliomas (LGGs), primary GBMs, and recurrent GBMs. Importantly, our analysis of 83,479 glioma infiltrating myeloid cells identifies 9 molecularly distinct myeloid subtypes: 4 microglia, 4 bone marrow-derived macrophage (BMDM), and dendritic cell subtypes. Importantly, five of these myeloid cell subtype gene signatures were independent predictors of patient survival in multiple datasets, demonstrating the importance of immune cells in disease progression and aggressiveness. Here, we report evidence for heterogeneous cell:cell communication between glioma and immune cells in different regions within a patient, using CellChat, Cellphone DB, and NicheNet tools. We also nominate immune modulators other than PD1/PDL1 and CTLA3 as more promising targets in GBM. Finally, we provide evidence that S100A4 is a promising novel immunotherapy target since its high-level expression is required for immune-suppressive macrophages and Tregs to block T cell infiltration and DC maturation.
TMIC-64. EXTRACELLULAR VESICLE TRAFFICKING IN GBM
Authors: Maire Cecile , Salviano-Silva Amanda , Kolbe Katharina , Westphal Manfred , Lamszus Katrin , Ricklefs Franz 
Published: November 2022

Abstract
Extracellular vesicles (EVs) are secreted by all cell types, including tumor cells, and are found in increased numbers in the plasma of GBM patients. EVs may contain high-value genetic material that can be useful for tracking tumor development, as well as membrane proteins that affect other cells. This prompted us to investigate how tumor EVs might influence immune cells in glioma, and in primary and secondary lymphoid organs as well as in the circulation. To this end we used a syngeneic GBM mouse model and tracked tumor EVs from the brain to the meninges, cervical lymph nodes, plasma, bone marrow and spleen. Interestingly, we were able to identify tumor EVs mostly in the cervical lymph nodes by ImageStream imaging flow cytometry just 30min after tumor EV injection into the brain. However, when tumor EVs were produced by a large gliomas transfected with dTomato, we found them mainly in plasma, less frequently in bone marrow and never in the spleen. We confirmed these data by extracting DNA from EVs and detecting specific dTomato sequences using digital droplet PCR. In addition, we detected CD11b+ macrophages in the meninges that likely travel through the lymphatics that have taken up tumor EV or tumor material. We confirm that tumor EVs are capable of eliciting an immune response by activating T cells. However, prolonged contact and large number of EVs could also block antigen recognition by T cells and thus contribute to the propagation of an immunosuppressive environment in GBM.
TMIC-65. DISSECTING THE EXPRESSION AND FUNCTION OF ANGIOPOIETIN-1 IN BRAIN TUMORS
Authors: Langhnoja Jaldeep , Wei Xin , Arounleut Phonepasong , Phoenix Timothy 
Published: November 2022

Abstract
Angiopoietin-1 (Angpt1) is a secreted protein that can promote 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 across brain tumor types. Surveying its expression across pediatric and adult brain tumors we show Angpt1 is upregulated in glial brain tumors, including high-grade gliomas and ependymomas, and that expression patterns correlate with cell-type expression patters we recently described in the normal developing and adult brain. To examine the cell type and location of Angpt1 expression within tumors we have generated electroporation based high-grade glioma and ependymoma mouse models in Angpt1-GFP reporter knock-in mice. Angpt1-GFP expression is found mainly in tumor cells within both tumor models, with varying expression in high-grade glioma models based on driver mutations and molecular subtype. Single-cell transcriptomic studies in these mouse models are underway to further delineate expression across tumor and non-tumor cell types. Moreover, we are leveraging this flexible electroporation-based mouse brain tumor modeling platform to examine Angpt1 function within brain tumors. Preliminary data shows that including a DNA plasmid encoding Cre-recombinase induces recombination and loss of Angpt1 in our electroporation-based brain tumor models, and ongoing studies aim to delineate its function in tumor pathogenesis, including tumor angiogenesis and blood-brain barrier function.
TMIC-76. HUMANIN RELEASE FROM TUMOR ASSOCIATED MYELOID CELLS PROMOTES GLIOMA CHEMORESISTANCE
Authors: Cheng Jiying , Li Min , Flüh Charlotte , Synowitz Michael , Bhat Krishna , Balasubramaniyan Veerakumar , Kaelin Roland , Glass Rainer 
Published: November 2022

Abstract
Transcriptomic screens of brain tumor (glioblastoma; GBM) parenchymal cells indicated tumor supporting traits of the GBM microenvironment, but largely excluded mitochondrially enriched gene-sets. Here, we show that a mitochondrial transcript of GBM parenchymal cells contributes to therapy resistance. We inspected the non-coding transcriptome of human GBM associated myeloid cells (GAM) and observed an upregulation of the mitochondrial ribosomal subunit MT-RNR2, which contains an open reading frame for the signaling peptide humanin. Immunohistology disclosed that humanin was preponderant in GAM. In vitro assays with a range of human stem-like GBM cells (GSCs) revealed that nanomolar concentrations of humanin can drive tumor cell expansion and chemoresistance to temozolomide. A series of genetic, pharmacological and Western blotting experiments showed that extracellular humanin increased GSC viability via stimulation of the GP130/IL6ST receptor and MAPK (Erk) activation. Humanin responsiveness was subject to inter-individual heterogeneity and predominated in GSC with high expression levels of the IL6ST subunit. Mechanistically, humanin promoted the ATR-dependent DNA-repair machinery in GSCs via induction of the DNA-clamp component HUS1. A slice culture model containing human microglia and GSCs confirmed these observations. Humanin is absent from the mouse brain. Exogenous delivery of humanin into orthotopic GBM mouse models or over-expression specifically of a secreted humanin variant recapitulated the in vitro findings. Blockade of the trimeric interleukin receptor with the brain permeant, FDA-approved drug bazedoxifene blocked humanin-mediated chemoresistance in vitro and in vivo. Overall, we identified a clinically applicable compound together with a predictive marker to prevent chemoresistance in a human-specific GBM model.
TMIC-78. CIRCADIAN REGULATOR CLOCK DRIVES IMMUNOSUPPRESSION IN GLIOBLASTOMA
Authors: Xuan Wenjing , Hsu Wen-Hao , Khan Fatima , Dunterman Madeline , Pang Lizhi , Wainwright Derek , Ahmed Atique , Heimberger Amy , Lesniak Maciej , Chen Peiwen 
Published: November 2022

Abstract
The symbiotic interactions between cancer stem cells and the tumor microenvironment (TME) are critical for tumor progression. However, the molecular mechanism underlying this symbiosis in glioblastoma (GBM) remains enigmatic. Here, we show that circadian locomotor output cycles kaput (CLOCK) and its heterodimeric partner brain and muscle ARNT-like 1 (BMAL1) in glioma stem cells (GSCs) drive immunosuppression in GBM. Integrated analyses of the data from transcriptome profiling, single-cell RNA sequencing, and TCGA datasets, coupled with functional studies, identified legumain (LGMN) as a direct transcriptional target of the CLOCK–BMAL1 complex in GSCs. Moreover, CLOCK-directed olfactomedin-like 3 (OLFML3) upregulates LGMN in GSCs via the hypoxia-inducible factor 1-alpha (HIF1A) signaling. Consequently, LGMN promotes microglial infiltration into the GBM TME via upregulating CD162, and polarizes infiltrating microglia towards an immune-suppressive phenotype. In GBM mouse models, inhibition of the CLOCK–OLFML3–HIF1A–LGMN–CD162 axis reduces intratumoral immune-suppressive microglia, increases CD8+ T cell infiltration, activation and cytotoxicity, and synergizes with anti-PD1 therapy. In human GBM, the CLOCK-regulated LGMN signaling correlates positively with microglial level and poor prognosis. Together, these findings uncover the CLOCK–OLFML3–HIF1A–LGMN axis as a molecular switch that controls microglial biology and immunosuppression, thus revealing potential new therapeutic targets for GBM patients.
TMIC-80. SPATIOTEMPORAL GENOMICS OF HUMAN MEDULLOBLASTOMA WITHIN SUBGROUPS
Authors: Liu Hailong , Qiu Xiaoguang , Jiang Tao 
Published: November 2022

Abstract
Whereas evidences of single-cell studies have suggested the cellular diversity of medulloblastoma, the most common malignant brain tumor in childhood, the understanding of spatial status for specific cell populations and gene modules remains rudimentary. Herein, we comprehensively analyze single-nucleus RNA expression, chromatin accessibility and spatial transcriptomic profiling from 52 human medulloblastomas spanning four molecular subgroups, complemented with the bulk whole genome and RNA sequencing data across 300 samples. We comprehensively interrogated the composition of medulloblastoma microenvironment and spatially described the developmental trajectory from progenitor-like to differentiated malignant cells. Furthermore, distinct heterogeneity within molecular subgroups leads to the identification of twelve subtypes of medulloblastoma, which unfortunately lacks the cellular biology. By deciphering the copy number variation and transcriptional programs at single-cell resolution, we in-depth characterized medulloblastoma and mapped the activity of gene expression and transcription factor binding according to individual subtype. The WNT-β, SHH-γ, Group 3-β and Group 4-γ were observed in early differentiation stage. Harmony alignment revealed subtype-dependent modules recapitulated the neurodevelopmental gene enrichment, strongly correlating to clinical outcomes. Collectively, our findings provide spatiotemporally resolved insights into transcriptome and epigenome of twelve-subtype medulloblastoma allowing further refinement regarding clinical risk stratification strategies.
TMIC-83. SEX AND ANTI-GLIOMA IMMUNITY
Authors: Kaminska Bozena , Ochocka Natalia , Segit Pawel , Wojnicki Kamil , Jacek Karol , Grajkowska Wieslawa 
Published: November 2022

Abstract
Glioblastomas (GBMs) are aggressive, inevitably lethal brain tumors that are massively infiltrated by myeloid cells supporting tumor growth. The main myeloid cell populations encompass brain-resident microglia, bone marrow (BM)-derived monocytes/macrophages and dendritic cells. Interestingly, patients with glioblastoma show sex-dependent differences in the incidence rate (male-to-female ratio of 1.6:1 in GBMs and 2:1 in most malignant mesenchymal GBMs), transcriptomic profiles and patient responses to a standard therapy. Sex-related differences such as higher expression of pro-inflammatory genes in female microglia and stronger upregulation of MHCII coding genes in microglia from male GL261-bearing mice were detected (Ochocka et al. 2021). We employed Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-seq) to reliably dissect myeloid cell identities, states and evaluate dynamics of myeloid infiltration during progression of murine GL261 gliomas. We demonstrate the diversity of myeloid cells within the glioma microenvironment: glioma-activated microglia are the major source of cytokines attracting other immune cells, whereas BM-derived cells show the monocyte-to-macrophage transition and immunosuppressive phenotypes. This transition is coupled with a phenotypic switch from the IFN-related to antigen-presentation and tumor-supportive signatures. Moreover, we found striking sex-dependent differences in transcriptional programs and composition of myeloid cells in gliomas. Higher abundance of protumor macrophages in males correlated with greater tumor size. Re-analysis of single-cell omics data from human GBMs revealed the predominance of inflammatory monocytes in female GBMs and abundance of protumor macrophages in male GBMs. Our findings expand understanding of the complexity of anti-tumor immune responses in gliomas and may guide future therapies in consideration of patient sex. Studies supported by National Science Centre Poland research grants PRELUDIUM16 2018/31/N/NZ3/01696, OPUS 14 2017/27/B/NZ3/01605 and 2020/39/B/NZ4/02683.