bluuebunny/crossref_metadata_2025_split huggingface dataset:
TMET-36. ACID CERAMIDASE INHIBITION EXPLOITS SPHINGOLIPID VULNERABILITIES IN IDH MUTANT GLIOMAS
Authors: Zaibaq Faris , Dowdy Tyrone , Larion Mioara 
Published: November 2022

Abstract
The presence of the IDH mutation in gliomas is a major classifier of brain tumor subtypes and has several important implications for cancer growth. Our recent work uncovered that IDH-mutant tumors are susceptible to increased apoptosis via alterations of the sphingolipid pathway due to their excess production of pro-apoptotic ceramides over pro-proliferative sphingosine 1-phosphate (S1P). To that end, we proposed that this rheostat can be modulated to induce cell death in IDHmut tumors by targeting acid ceramidase, a critical sphingolipid enzyme in gliomas. We hypothesize that pharmacological inhibition of acid ceramidase will increase ceramide levels and therefore induce apoptosis in IDHmutgliomas. Using a preliminary drug screen, we have identified a group of haloacetate C2-ceramide derivatives known as SOBRACs that potently inhibit acid ceramidase. We selected five candidate compounds from this family and assessed the effectiveness of each drug in 3 I IDHmut (BT142, TS603, & U251mut) and 3 IDHmut (GSC923, GSC827, U251wt) patient-derived glioma cell lines, as well as non-immortalized normal human astrocytes, using the CCK8 cell viability assay. Our results indicate that the SOBRAC drugs are nearly 10 times more potent in IDH-mutant tumors compared to IDHmut cell lines. Additionally, the SOBRAC drugs are more effective than other known acid ceramidase inhibitors, making them attractive as potential novel therapeutics. To date, azide-SOBRAC is the most potent drug in the family, with EC50 value of 300 nM in BT142 cells (IDHmutmut
TMET-39. INHIBITION OF THE TCA-CYCLE IS SYNTHETICALLY LETHAL WITH LOSS OF FUNCTION OF BCL-XL IN GLIOBLASTOMA
Authors: Nguyen Trang , Shang Enyuan , Torrini Consuelo , Shu Chang , Westhoff Mike-Andrew , Karpel-Massler Georg , Siegelin Markus 
Published: November 2022

Abstract
Glioblastoma (GBM) remains an incurable disease, requiring more effective therapies. Through CRISPR and RNAi library screening interrogation we identified several TCA-cycle enzymes as essential for GBM growth. By combining a transcriptome and metabolite screening analyses we discovered that inhibition of the TCA-cycle by the clinically validated drug compound, CPI-613, is synthetically lethal with Bcl-xL loss of function (genetically and through the clinically validated BH3-mimetic, ABT263) in patient-derived xenograft as well neurosphere GBM cultures. Carbon tracing experiments (U-13 C-glucose and U-13 C-glutamine) and extracellular flux analysis showed that CPI-613 interferes with mitochondrial respiration. In turn, CPI-613 mediated energy deprivation drives an integrated stress response with an up-regulation of the BH3-only domain protein, Noxa in an ATF4 dependent manner as demonstrated by genetic loss of function experiments. Consistently, silencing of Noxa rescued from cell death induced by CPI-613 as well as by the combination treatment of ABT263 and CPI-613 in model systems of GBM. In patient-derived xenograft models of GBM in mice, the combination treatment of ABT263 and CPI613 suppressed tumor growth more potently than each compound on its own. Therefore, combined inhibition of Bcl-xL along with interference of the TCA-cycle might be a novel treatment strategy for GBM.
TMIC-02. PRE-SURGICAL IMMUNE CHECKPOINT BLOCKADE RESHAPES THE IMMUNE LANDSCAPE AND SPATIAL ARCHITECTURE OF METASTATIC BRAIN TUMORS
Authors: Sun Lu , Kienzler Jenny , Reynoso Jeremy , Lee Alexander , Owens Geoffrey , Everson Richard G , Nathanson David , Cloughesy Timothy , Liau Linda M , Hugo Willy , Kim Won , Prins Robert 
Published: November 2022

Abstract
Brain tumors reside in a modified microenvironment where inflammatory processes are heavily regulated. Nevertheless, our recent study showed a significant immune infiltration in recurrent glioblastoma (rGBM) treated with neoadjuvant PD-1 checkpoint blockade therapy. In comparison to GBM, the intracranial response of brain metastases (BrM) to immunotherapy has been less well studied. To test this question, we investigated the effect of pre-surgical immune checkpoint blockade (ICB) on the immune compartments of BrM, using multiplex immunofluorescence, single-cell RNA sequencing and spatial transcriptomics on a total of 17 patients. We found that ICB naïve BrM featured an immune exclusion phenotype with accumulation of immune cells in the fibrovascular stroma, necrotic and hemorrhagic peritumoral areas. Following ICB treatment, T cells and monocyte-derived macrophages were then observed within the tumor parenchyma. Computational receptor-ligand analysis suggested that the tumor-infiltrating T cells and macrophages were highly engaged by checkpoint receptor-ligand pairing, which may drive the T cells into an advanced exhausted state. To further explore the organization and interactions between the immune, stroma and tumor cells in BrM, we utilized the sequencing-based spatial transcriptomics technology. Our spatial transcriptomics data further highlighted the distinct spatial architectures between ICB naïve and –treated BrM tumors. It also pinpointed a unique macrophage subset that are preferentially co-localized with the brain vasculature cells and confined the immune infiltrates to the perivascular space. In summary, our study revealed ICB-induced marked changes in the immune composition and spatial organization in BrM and offers insights into new combination therapies that can help improve the clinical efficacy of immunotherapy for BrM patients.
CNSC-24. THE EPILEPTIC LANDSCAPE OF IDH MUTANT GLIOMAS
Authors: Drumm Michael , Wang Wenxia , Burdett Kirsten B , Sears Thomas , Javier Rodrigo , Cotton Kristen , Webb Brynna , Stolz Jacob , Byrne Kayla , Unruh Dusten , Walshon Jordain , Steffens Alicia , McCortney Kathleen , Bushara Omar , Weston Alyssa , He Suning , Lukas Rimas , Finan John , Franz Colin , Kurz Jonathan , Templer Jessica , Swanson Geoff , Horbinski Craig 
Published: November 2022

Abstract
Tumor-associated epilepsy (TAE) is a frequent complication of diffusely infiltrative gliomas, and impairs quality-of-life. We previously showed that isocitrate dehydrogenase 1 mutant (IDHmut) gliomas were associated with preoperative seizures, and that D2HG increased synchronized bursts in cultured neurons (PMID: 28404805). But the mechanism whereby this occurs, whether IDHmut inhibitors can block this, and whether seizure risk varies by IDHmut status post-operatively, are unknown. We discovered that exogenous 3 mM D2HG had a 150% greater effect on the firing rate of cultured mouse cortical neurons when nonneoplastic glia cells were present versus when they were absent (P=0.002). Coculture with patient-derived IDHmut glioma cells increased the firing rate of human cortical neuron/astrocyte spheroids by up to 272%, and the IDHmut inhibitor AG881 reduced the excitatory effect of IDHmut glioma cells on spheroids by 79% (P=0.0008). Using a novel in vivo model of TAE, wherein EEG recordings were taken of immunocompetent mice engrafted with isogenic mouse glioma lines (NRAS/ATRX/TP53mut ± IDHmut), we found that IDHmut gliomas produced 7.6-fold more epileptiform spikes than IDHwt gliomas (P=0.004). RNA-Seq analysis of the peritumoral mouse brain tissue showed that this increase in spikes was associated with significantly increased expression of key genes known to be upregulated in epilepsy, including SLC12A5, THSB1, VEGFA, FOSL2, and SYNPO. Treatment with 5 mg/kg AG881 by daily oral gavage reduced those spikes in IDHmut-engrafted mice by 51% within three days (P=0.027), whereas vehicle control had no effect (P=0.33). Among 247 patients with grade 2–4 adult-type diffuse gliomas, multivariable time-to-event analysis showed that post-operative seizure risk was positively associated with pre-operative seizures, subtotal resection, and IDHmut astrocytoma. Together, these data show that (i) the D2HG product of IDHmut gliomas increases neuronal excitation in a glial-dependent manner; (ii) IDHmut also affects post-operative seizure risk; (iii) IDHmut inhibitors may improve TAE control.
TMIC-08. FRIEND AND FOE: RADIATION THERAPY MODULATES GLIOBLASTOMA IMMUNE EVASION VIA EXTRACELLULAR VESICLES
Authors: Schweiger Markus , Amoozgar Zohreh , Tannous Bakhos 
Published: November 2022

Abstract
Glioblastoma (GBM) is the most common form of malignant primary brain tumor and despite optimal treatment, long-term survival remains incredibly rare. Radiation therapy (RT) leads to successful initial tumor regression but recurrence is inevitable. Previous studies have shown that ionizing radiation changes the composition of the tumor microenvironment and alters the expression of immune-related markers on tumor cells. Extracellular vesicles (EVs) are vesicular bodies of cellular origin and secreted by nearly every cell. They have been shown to carry a variety of cargo (DNA, proteins, RNAs, lipids) which can be taken up by other cells. Notably, previous studies highlight that EVs drive GBM progression and immune evasion by acting as multifunctional signaling complexes. Here we show that ionizing radiation of GBM cells results in an altered EV secretome and further facilitates the uptake of EVs in recipient cells. In addition, EVs secreted by GBM cells following radiation modulate the tumor microenvironment by manipulating the innate as well as the adaptive immune response. Macrophages exposed to EVs from irradiated GBM cells switched to the tumor supportive M2 phenotype and exhibited decreased phagocytotic ability.We dissected a novel mechanism by which GBM evades the immune system with the help of EVs following RT, pointing towards novel therapeutic strategies to prevent GB recurrence.
TMIC-14. DIFFUSE P16INK4A EXPRESSION IS ASSOCIATED WITH TUMOR CELL SENESCENCE AND SENESCENCE-ASSOCIATED SECRETARY PHENOTYPE RELATED TO IMMUNE MICROENVIRONMENT IN GLIOBLASTOMAS
Authors: Roh Tae Hoon , Kim Young Hwa , Park So Hyun , Eom Soyeong , Park Tae Jun , Kim Jang-Hee , Kim Se-Hyuk 
Published: November 2022

Abstract
Cellular senescence (CS) is a state of irreversible cell cycle arrest, and the expression of p16INK4a in cells is one of the reliable markers for CS. However, senescent cells are metabolically active with the senescence-associated secretory phenotype (SASP), which can influence the tissue microenvironment by paracrine signaling to the adjacent tumor, non-tumor, and immune cells. In the present study, we evaluated p16INK4a expression in glioblastoma and investigated its association with CS and SASPs. We analyzed the expression of p16INK4a in 73 glioblastomas by immunostaining. To examine the association of p16INK4a expression and CS, we performed senescence-associated β-galactosidase (SA-β-Gal) staining, a standard marker of CS, using glioblastoma cell lines and fresh frozen tumor tissues. For SASPs analysis, RNA sequencing with Gene Set Enrichment Analysis (GSEA) was performed. Among 73 glioblastomas, twenty-eight cases (38.4%) revealed diffuse strong p16INK4a expression in tumor cells. The glioblastoma with diffuse p16INK4a expression (GMDP) patients were younger (52.4 vs. 59.2 years) and showed prolonged overall survival (median: 25.5 vs. 12.3 months) compared to those harboring negative expression. In vitro analysis, p16INK4a over-expressed glioblastoma cell line showed increased expression of SA-β-Gal which indicates CS. In addition, fresh frozen tissues from GMDP also revealed SA-β-Gal positivity. RNA sequencing analysis revealed that splicing or protein biosynthetic genes were enriched in GMDP, and GSEA showed significant enrichment of SASP genes (false discovery rate &lt; 0.05), especially chemokines associated with monocytes and macrophages. Our data suggest that increased expression of p16INK4a in glioblastoma is associated with tumor cell senescence, and SASPs from senescent tumor cells could be one of the crucial modulators in the tumor immune microenvironment.
CNSC-25. METABOLISM ACROSS BRIDGE OF SIGHS TO ONCOHISTONES
Authors: S.Senga Sasi 
Published: November 2022

Abstract
Brain tumours continue to be one of the leading causes of childhood mortality related to cancers. Oncohistones such as H3K27M, and H3G34R mutations have been linked to childhood brain tumours. The reason for the incidence of Oncohistone mutation in a developmental setting provides some novel insight for better therapeutics. The maintenance of the progenitor state might be driven by metabolism dictated Oncohistone mutations at the expense of differentiation in the developing brain paving way for tumourigenesis. I propose methods to target metabolic disturbances in the developing brain even prior to the rise of such somatic oncohistone mutations. Additionally, I provide insight into the reason for selective co-mutations that occur with specific Oncohistones in childhood brain tumours providing a rationale for effective therapeutics. In 2021, I proposed neuronal signalling as an Hallmark of cancer, in the context of childhood brain tumours, the nervous system functions as a fulcrum between metabolic reprogramming and the rise of oncohistone mutations leading to epigenetic reprogramming. The nervous system is a lucrative target in inhibiting the metabolic cues that support oncohistones. Metabolic reprogramming may underpin epigenetic reprogramming driving the developing brain across the Bridge of Sighs towards tumourigenesis.
TMIC-16. INTRATUMORAL THROMBOSIS INITIATES HYPOXIA AND NECROSIS TO DRIVE TUMOR PROGRESSION THROUGH DRAMATIC TUMOR MICROENVIRONMENTAL ALTERATION
Authors: Markwell Steven , Olson Cheryl , Li Jiabo , Shih Ling-Kai , Ross James , Brat Daniel 
Published: November 2022

Abstract
All GBM molecular subsets share the common trait of accelerated progression following necrosis which cannot be adequately explained by cellular proliferation arising from accumulated genetic alterations. We suggest that development of necrosis is much more than a passive phenomenon related to rapid growth but rather is a driving force behind TME restructuring responsible for sustaining accelerated expansion. Current tumor models fail to adequately mimic the magnitude of post-necrotic restructuring within the microenvironment and remain overly reliant on post-mortem analyses, obligating researchers to extrapolate causal relationships between necrosis and progression phenomena during tumor evolution. In GBM (WHO grade 4), the most malignant primary brain tumor, vascular pathology and central necrosis precede rapid, radial expansion. Mechanisms enabling selective fitness within a hypoxic/anoxic GBM setting remain poorly understood. Nanostring GeoMX spatial profiling demonstrates M1-like TAM enrichment in non-necrotic human samples and M2-like TAMs in perinecrotic regions. Our immunocompetent RCAS/tv-a model aptly captures events seen in human gliomas, exposing dynamic temporal and spatial changes that facilitate GBM progression, incorporating unique microenvironmental stressors typically absent from GBM animal models, specifically emerging central necrosis. Simultaneously, our in vitro models scrutinize how hypoxia-dependent signaling between GBM cells, microglia and monocytes alter TAM accumulation and function in the TME. TAMs increase dramatically with the onset of necrosis, with a preferential localization to the hypoxic zone in the perinecrotic niche, which supports their survival. Flow cytometry on digested pre- and post-necrotic GBMs, showed increased TAM accumulation at 6 weeks vs. 2 weeks (necrosis emerges in week 4-5). Our in vivo data along with in silico analysis of Ivy GAP and TCGA datasets suggests GBM cells within the peri-necrotic niche attract and polarize TAMs through MIF secretion, necrotic DAMP (adenosine, S100B) release, and arginase secretion to suppress T cells.
CNSC-26. NETWORK SIGNATURES OF SURVIVAL IN BRAIN TUMOUR GENETICS
Authors: Ruffle James , Mohinta Samia , Pombo Guilherme , Gray Robert , Kopanitsa Valeriya , Lee Faith , Brandner Sebastian , Hyare Harpreet , Nachev Parashkev 
Published: November 2022

Abstract
Tumor heterogeneity is increasingly recognized as a major obstacle to therapeutic innovation across neuro-oncology. Gliomas typically exhibit a spectrum of possible genetic mutations, reflecting multiple, potentially complex interactions across distinct molecular pathways. Predicting disease evolution and prescribing individually optimal treatment plausibly requires statistical models complex enough to capture the intricate genetic structure underpinning oncogenesis. Here we formalize this task as the discovery of distinct patterns of connectivity within network representations of the interactions between genetic loci. Evaluating multi-institutional clinical, genetic, and outcome data from 7847 consecutive patients over a 14-year period, we employ Bayesian stochastic block modelling to reveal a hierarchical network structure of tumor genetic interactions spanning (molecularly confirmed) IDH-wildtype glioblastoma, IDH-mutant oligodendroglioma and astrocytoma. We show that this structure not only identifies the patients’ diagnosis, but predicts individual survival with greater fidelity (Cox’s proportional hazard cross-validated (CPH-CV) concordance = 0.78; Bayesian 12, 24 and 36-month survival models = R2 0.31, 0.40 and 0.46, respectively) than the latest WHO tumor classification (CPH-CV concordance = 0.77; Bayesian 12, 24 and 36-month survival models = R2 0.26, 0.36 and 0.39, respectively) or linear models of genetic features (CPH-CV concordance = 0.76; Bayesian 12, 24 and 36-month survival models = R2 0.26, 0.35 and 0.37, respectively). For example, a diagnosis of IDH-wildtype glioblastoma yielded median survivals varying from 289 days in patients with the signature of marked EGFR amplification, MGMT methylation, and histone mutations, to 425 days in those with the signature of TERT mutations, histone and EGFR wild-types, and variable MGMT methylation. These findings suggest network-based analysis can reveal distinct signatures of survival with better prognostic fidelity than current gold standard diagnostic categories.
TMIC-30. EFFICIENT, QUANTITATIVE MAPPING OF TUMOR-IMMUNE NEIGHBORHOOD COMPOSITION IN GLIOBLASTOMA USING CASSATT
Authors: Brockman Asa , Khurana Rohit , Bartkowiak Todd , Hayes Madeline , Mobley Bret , Irish Jonathan , Ihrie Rebecca 
Published: November 2022

Abstract
The microenvironment surrounding brain cancer cells, and their position relative to anatomical features such as the vasculature, is a critical contributor to tumor malignancy. Immunohistochemical staining is widely used to examine such multicellular interactions, and approaches like cyclic immunohistochemistry (cycIHC), multiplexed immunofluorescence, or mass-based imaging can include up to 100 channels of interest. However, large (often &gt; 50 GB) datasets from cycIHC or comparable approaches currently require an expert data scientist to concatenate open-source tools for each step of image pre-processing, registration, and segmentation, or the use of expensive proprietary software. We generated an open-source, unified, and user-friendly workflow for processing and analyzing cycIHC data - Cyclic Analysis of Single-Cell Subsets and Tissue Territories (CASSATT). CASSATT registers scanned slide images across all rounds of staining, segments individual nuclei, and scores marker expression on each detected cell. Beyond straightforward data analysis outputs such as dimensionality reduction, clustering, cell population identification and quantification, CASSATT explores the spatial relationships between cell populations via a statistical analysis module that can be applied to other high-dimensional imaging data types. In brief, it helps users identify populations of cells that interact - or do not interact - at frequencies that are greater than those occurring by chance. It also identifies specific ‘neighborhoods’ based on the cell types that surround each cell in the sample. The presence and location of these neighborhoods can be compared across slides or within distinct regions within a tissue. Within a newly generated cycIHC dataset consisting of 6 glioblastoma tissue sections processed through 8 cycles of chromogenic IHC staining, CASSATT successfully identified populations detected in parallel flow cytometry analyses and revealed specific associations between tumor and immune populations. Additional successful benchmarking was completed on a published tissue microarray dataset consisting of 107 cores processed through 18 cycles of staining and imaging.
TMIC-31. ADI-PEG20 RESTORES IMMUNITY IN THE TUMOR MICROENVIRONMENT AND ERADICATES GBM TUMORS IN MICE WHEN COMBINED WITH RADIATION
Authors: Symington Jake , Perryman Richard , Morse Sophie , O'Neill Kevin , Want Elizabeth , Syed Nelofer 
Published: November 2022

Abstract
Glioblastoma (GBM) is a primary brain tumour with poor prognosis and limited treatment options. We previously demonstrated that arginine deprivation by ADI-PEG20 is effective in GBM tumors which are auxotrophic for arginine. We also reported that ADI-PEG20 has efficacy in arginine non-auxotrophic GBM when combined with radiation in the presence of an immune competent environment. Here, we present detailed mechanistic insight into our latter findings using multiplex Imaging Mass Cytometry (Fluidigm) and Spatial Transcriptomics (10x Genomics) of tumor samples treated with ADI-PEG20. ADI-PEG20 enhanced the expression on MHC class II on infiltrating CD11c+ dendritic cells and these cells colocalised specifically with CD4+ T cells. We also observed changes in the expression of PD-1/PD-L1 with ADI-PEG20 and this was further enhanced when ADI-PEG20 was combined with radiation. Moreover, combination therapy increased the expression of chemokines involved in immune cell recruitment and activation. Our findings demonstrate that arginine deprivation restores immune function in the tumor microenvironment of arginine non-auxotrophic GBM tumors and suggests that combinations with immunotherapies will further enhance efficacy for GBM tumors.
TMIC-33. ARGINASE-1 AND ITS ROLE IN THE GLIOBLASTOMA MICROENVIRONMENT
Authors: Zamler Daniel , Shingu Takashi , Jiang Shan , Yu Fei , Jiang Yingda , Draetta Giulio , Hu Jian 
Published: November 2022

Abstract
An average GBM has roughly 30% infiltration of myeloid cells, the highest reported case at 70% infiltration, with some variation dependent on subtype. When we consider this fact in combination with the advent and success of immunotherapies in similar cancer types, the logical next step follows that myeloid cells, which are of the immune lineage, have the potential to clear this aberrant growth. Known for their incredible phagocytic capacity, myeloid cells are among the first responders to an injury to control pathogens and clear apoptotic cells from the site of an insult. Myeloid cells, through poorly understood mechanisms, undergo a switch after 3-5 days from attacking pathogens and clearing dead cells to secretion of growth cytokines to promote wound healing. We posit these myeloid cells may be tricked into erroneously supporting the tumor cells in an attempt to “heal the wound” instead of mounting an immune response. The enzyme responsible for this switch from pathogen response to wound healing is called Arginase-1 (Arg1). When Arg1 is upregulated it has a two pronged effect, the first is creation of peroxynitrite which is actively immunosuppressive to both myeloid and T-cells. The second is an increase in ornithine when Arg1 cleaves arginine into ornithine and urea, which can be used to create the building blocks for cellular growth as well as to create collagen, which is necessary for wound repair and found in high levels in brain tumors. Our hypothesis is that through manipulation of the Arg1 axis in myeloid cells we will increase anti-tumor response. We show the groundwork for evaluating whether or not this is a viable therapeutic target in GBM as well as assess currently available compounds for inhibition or Arg1 in the CNS.