bluuebunny/crossref_metadata_2025_split huggingface dataset:
TAMI-15. PROSTATE SPECIFIC MEMBRANE ANTIGEN EXPRESSION IN GLIOBLASTOMA TUMOR AND ENDOTHELIAL CELLS
Authors: Stopa Brittany , Degen Katherine , Michelhaugh Sharon , Juhasz Csaba , Mittal Sandeep 
Published: November 2021

Abstract

INTRODUCTION
Prostate specific membrane antigen (PSMA) has emerged in recent years as a potential target for PET imaging of CNS tumors. Originally studied for imaging in prostate cancer, it was incidentally found to have selective uptake in some CNS tumors. Early studies have shown promise for PSMA tracer use in glioblastoma (GBM), but more research is needed to characterize the PSMA expression profile in GBM.

METHODS
Formalin-fixed paraffin-embedded tissues of 26 GBMs were immunostained with PSMA antibody. Stained sections were scored, using 5 images per tumor, in total 130 observations. Sections were assessed for extent and intensity of PSMA expression, in tumor cells and neovascular endothelial cells. Extent of expression: 0% (none), 1-9% (very low), 10-39% (low), 40-69% (moderate), &gt; 70% (high). Intensity of expression: no staining (none); barely perceptible staining (low); readily apparent at low magnification (moderate); and maximum-intensity staining (high).

RESULTS
Extent of PSMA expression in tumor cells was mostly very low (76 out of 130, 58%), but intensity was often moderate (42, 32%), low (41, 32%), or high (39, 30%). The most prevalent combination was very low extent with low or moderate intensity (both 30, 23%). Endothelial cells were absent in 61 (47%) sections. Extent of expression in endothelial cells was mostly high (28, 41%), and intensity was often moderate (25, 36%) or high (20, 29%). The most prevalent combination was high extent with moderate (14, 20%) or high intensity (13, 19%).

CONCLUSION
PSMA expression was variable and was seen in both vascular endothelial cells and tumor cells. The mechanism of PSMA expression in GBM may not be straightforward, but rather may vary by cell type and tumor mutation status. Further tissue studies to understand the specific mechanism are needed to establish the potential use of PSMA PET as a neuroimaging modality in GBM.
TAMI-16. THREE-DIMENSIONAL ORGANOID CULTURE UNVEILS RESISTANCE TO CLINICAL THERAPIES IN ADULT AND PEDIATRIC GLIOBLASTOMA
Authors: Sundar Swetha , Shakya Sajina , Wallace Lisa , Barnett Austin , Sloan Andrew , Recinos Violette , Hubert Christopher 
Published: November 2021

Abstract

BACKGROUND
Glioblastoma (GBM) is the most common primary brain tumor with a dismal prognosis. The inherent cellular diversity and interactions within tumor microenvironments represent a significant challenge to effective treatment. Traditional culture methods may mask the complexity of such interactions while three-dimensional (3D) organoid culture systems derived from patient cancer stem cells (CSCs) can preserve cellular complexity and microenvironments. Our objective was to determine whether organoid cultures show increased patterns of resistance to potential clinical therapies compared to traditional sphere cultures.

METHODS
Adult and pediatric surgical specimens were collected and established as 3D organoids. We created organoid microarrays and visualized bulk and spatially defined differences in cell proliferation using immunohistochemistry (IHC) staining, as well as cell cycle analysis by flow cytometry with 3D regional labeling. We tested the response of CSCs grown in each culture method to temozolomide, ibrutinib, lomustine, ruxolitinib, and radiotherapy using proliferative and viability assays.

RESULTS
Compared to sphere cultures from the same patient, organoids showed diverse proliferative cell populations and broad resistance to all therapies tested, albeit with both intraspecimen and interspecimen variability in the extent of resistance. Organoid specimens demonstrated a blunt response to current GBM standard of care therapy (combination temozolomide and radiotherapy) and maintained both cellular proliferation in their outer rim and overall structure and viability compared to the matched sphere specimens.

CONCLUSIONS
Our results suggest that growth of tumor specimens as organoid cultures may better reflect the cellular diversity and clinical reality of GBM therapeutic response. Patient-derived GBM organoids offer a valuable complement to traditional culture methods and may have powerful predictive capability of personalized drug sensitivities and therapeutic resistance.
TAMI-18. DIFFERENTIAL LIPID METABOLISM IN CANCER MICROENVIRONMENTS LEADS TO A REQUIREMENT FOR FATTY ACID DESATURASES FADS1 AND FADS2 IN GBM CANCER STEM CELL MAINTENANCE
Authors: Shakya Sajina , Gromovsky Anthony D , Hale James S , Knudsen Arnon M , Prager Briana , Wallace Lisa , Penalva Luiz O , Brown H Alex , Kristensen Bjarne , Rich Jeremy N , Lathia Justin , Brown J Mark , Hubert Christopher 
Published: November 2021

Abstract
Glioblastoma (GBM) is marked by cellular heterogeneity through microenvironments of a tumor, including metabolic heterogeneity. While altered cellular metabolism in cancer is well-known, how lipid metabolism is altered in different GBM microenvironmental conditions and cancer stem cell (CSC) states within a tumor remains an open question. We developed 3-dimensional GBM organoid models that mimic the transition zone between nutrient-rich cellular tumor and nutrient-poor psuedopalisading/perinecrotic tumor regions and performed spatially defined RNA-sequencing to investigate lipid metabolism. Spatial analysis revealed striking differences in metabolism between diverse cell populations from the same patient, with lipid enrichment in the hypoxic organoid cores and the pseudopalisading regions of patient tumors. This was accompanied by regionally restricted upregulation of lipid droplets and Hypoxia Inducible Lipid Droplet Associated gene expression in organoid cores and in the pseudopalisading regions of clinical GBM tumors. Using targeted lipidomic analysis, we assessed differences in acutely enriched CSC and non-CSCs from patient-derived models to explore the link between stem cell state and lipid metabolism. CSCs have low lipid droplet accumulation compared to non-CSCs in organoids and xenograft tumors, and prospectively sorted lipid-low GBM cells are functionally enriched for stem cell activity. This suggests lipid metabolism may not be simply a product of the microenvironment but also may be a reflection of cellular state. CSCs had decreased levels of major classes of neutral lipids compared to non-CSCs, but had significantly increased polyunsaturated fatty acid production due to increased expression of fatty acid desaturases FADS1 and FADS2. FADS1 and FADS2 expression are both essential to maintain CSC viability and self-renewal. Our data demonstrate that spatially and hierarchically distinct lipid metabolism phenotypes occur clinically in the majority of patients, can be recapitulated in laboratory models, and these altered lipid metabolic pathways may represent therapeutic targets for GBM.
TAMI-21. TUMOR-ASSOCIATED MICROGLIA GUIDE GBM INFILTRATION VIA PLEXIN-B2
Authors: Kang Sangjo , Sattiraju Anirudh , Li Yuhuan , Wahane Shalaka , Hanna Theo , Friedel Roland , Zou Hongyan 
Published: November 2021

Abstract
Glioblastoma (GBM) is the most common malignant primary brain tumor. The nature of invasiveness of GBM makes complete surgical resection difficult. However, how GBM cells achieve wide infiltration in the brain is poorly understood. Microglia, the resident immune cells in the brain can support GBM growth and invasion, but the underlying mechanisms remain elusive. Here, we show that microglia are activated in a wide field away from tumor boundaries, ahead of tumor cell infiltration. Invading GBM cells are in close contact with microglia, progressively aligned with one another in the direction of tumor invasion. Moreover, ECM is also aligned with the infiltrating tumor and microglia, which may serve as invasion tracks in the brain. Mechanistically, we demonstrate that microglia direct cellular alignment and ECM remodeling in the invasion tracks through an axon guidance receptor Plexin-B2. Myeloid-specific ablation of Plexin-B2 perturbs microglia and tumor cell alignment, microglia migration, ECM organization, and GBM invasiveness. Together, our data reveal a hitherto under-appreciated role of microglia in providing directional cues for GBM invasion through physical interaction and alignment of ECM and tumor cells, thus providing new insights and novel molecular targets in curbing GBM invasion.
TAMI-24. INHIBITION OF GBM INVASION BY THE Α-AMINO-3-HYDROXY-5-METHYL-4-ISOXAZOLEPROPIONIC ACID (AMPA) GLUTAMATE RECEPTOR ANTAGONIST PERAMPANEL
Authors: Sarnow Katharina , Kanli Georgia , Keunen Olivier , Bjerkvig Rolf 
Published: November 2021

Abstract

BACKGROUND
Extensive tumor cell invasion within the brain represents a major problem for effective treatment of glioblastomas (GBMs). The invasive processes can be divided into three types: Collective cell invasion, perivascular infiltration, and single-cell invasion into the brain parenchyma. GBM cells can form synapses with neural cells pointing at an extensive communication network between brain and GBM cells which can be mediated via the metabolites Glutamine and Glutamate both needed for GBM cell proliferation. In this context, it has been shown in preclinical models that Perampanel, an antiepileptic agent, functioning as non-competitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor antagonist, has an inhibitory effect on GBM growth. To delineate how Perampanel affects GBM invasion, we utilised a highly characterized 3D GBM-brain organoid invasion model where single-cell invasion was studied in real-time following Perampanel treatment.

METHODS
A brain coculture model, consisting of rat brain organoids expressing various markers of the human adult brain, where confronted with GFP-labelled tumor cells. By using time-lapse confocal microscopy, we quantified single-cell invasion patterns and speed of invasion using two glioma stem cell models (BG5 and BG7).

RESULTS
Perampanel treatment significantly reduces tumor cell invasion into the brain organoids with the strongest effect seen in the most invasive GBM (BG5). The single-tumor cell invasion ratio was reduced by 72 % compared to the control (p= 0.0033). In contrast, collective cell invasion was reduced by 19 % (p= 0.028). Statistical analysis was performed using an unpaired sample t-test.

CONCLUSION
The AMPA glutamate receptor antagonist Perampanel significantly inhibits GBM invasion, suggesting an important role of the glutamate-glutamine cycle between the GBM cells and neurons in the invasion process. Moreover, this communication and exchange of metabolites seem to be more prominent where single GBM cells invade into the brain parenchyma compared to areas where collective invasion take place.
TAMI-25. UPREGULATION OF CREATINE METABOLISM BY MYELOID CELLS RESULTS IN GLIOBLASTOMA PROGRESSION
Authors: Rashidi Aida , Cordero Alex , Castro Brandyn , Hou David , Dapash Mark , Zhang Peng , Han Yu , Lopez-Rosas Aurora , Chandel Navdeep , Lesniak Maciej , Chang Catalina , Miska Jason 
Published: November 2021

Abstract
Malignant brain tumors are uniquely immunosuppressive, with a predominant infiltration of immunosuppressive tumor-associated myeloid cells (TAMCs) and a deficit in T-cells unrivaled to any other tumor. This unique tumor microenvironment (TME) promotes resistance to both conventional and immune therapies for this disease. The underlying mechanisms by which TAMCs promote glioblastoma (GBM) progression are not fully understood. We found that TAMCs specifically upregulate de-novo creatine metabolism within GBM using unbiased genetic and metabolic screening. This metabolic phenotype was confirmed in human GBM patients by comparing peripheral versus tumor-infiltrating myeloid cells. Examination of de-novo creatine generation using Carbon13 arginine flux revealed that TAMCs, but not tumor-infiltrating CD8+ T-cells, can produce creatine. Furthermore, we demonstrate that TAMCs actively secrete de-novo generated creatine into cell cultures. Examination of the single-cell microenvironment of GBM revealed that malignant cells preferentially express the creatine transporter, indicating that TAMC-derived creatine is taken up by GBM. Notably, SLC6A8 is directly upregulated in the context of hypoxia and suggests that creatine uptake is a mechanism to promote survival under hypoxic stress. Indeed, exogenous creatine supplementation promoted both the migration and survival of multiple glioblastoma cell lines in-vitro. Utilizing an established inhibitor of creatine metabolism, β-Guanidinopropionic acid (β -GPA), we found that β -GPA blocks both the migration and survival of glioma cells under hypoxic stress. Lastly, β -GPA also inhibited creatine secretion by TAMCs, showing that creatine blockade can also influence TAMC metabolic phenotype. In the future, we will examine the importance of creatine metabolism on both immune suppression and tumor progression in-vivo. This work provides novel insights into the role of creatine metabolism in GBM and identifies a unique therapeutic avenue for this devastating disease.
TAMI-32. CORRELATION BETWEEN RADIOSENSITIVITY INDEX AND M2 MACROPHAGE PROPORTION IN TUMOR MICROENVIRONMENT OF GLIOBLASTOMA
Authors: Jang Bum-Sup , Kim In Ah 
Published: November 2021

Abstract

BACKGROUND
Tumor-associated macrophages (TAMs) Macrophage are predominant in glioblastoma tumor microenvironment (TME), supporting for neoplastic cell expansion and invasion. We investigated the relationship between radiosensitivity of glioblastoma and M1/M2 macrophage profiles in bulk and single cell RNA sequencing datasets.

METHODS
We used radiosensitivity index (RSI) gene signature and estimated RSI score based on the ranking of genes by expression level. Two large glioma datasets – The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) – were employed to identify whether RSI is clinically predictive of overall survival following radiation therapy. To analyze the association between M1/M2 macrophages and RSI within spatial context, the Ivy Glioblastoma Atlas Project dataset was investigated and single cell RNA sequencing dataset (GSE84465) was analyzed as well. Macrophages were profiled using a deconvolution algorithm, CIBERSORTx.

RESULTS
The RSI-high group having radioresistant tumors showed worse overall survival than the RSI-low group in both the TCGA (HR=1.87, 95% CI=1.06-3.29, P=0.031) and the CGGA (HR=1.61, 95% CI=1.04-2.50, P=0.031) glioblastoma population. In the Ivy Glioblastoma Atlas Project dataset, radiosensitive tumor having lower RSI was significantly more found in more vascular region including hyperplastic and microvascular region (coefficient=-0.07, P=0.001), meanwhile, radioresistant tumor was significantly clustered in necrotic region including perinecrotic and pseudopalisading regions (coefficient=0.07, P&lt; 0.001). The proportion of M1/M2 macrophage and RSI score showed an inverse relationship (coefficient=-0.23, P=0.015), indicating that radioresistant glioblastomas are related with TME having more M2 than M1 macrophage. In single cell RNA sequencing dataset composed of immune and tumor cells collected from four patients, mean RSI of neoplastic cells was positively correlated with high proportion of M2 macrophages.

CONCLUSION
RSI can predict radiation response in terms of overall survival in glioblastoma patients. High proportion of M2 macrophage may play an important role in TME of radioresistant glioblastoma.
TAMI-46. FRIEND AND FOE: RADIATION THERAPY INCREASES GLIOBLASTOMA IMMUNE EVASION VIA EVS
Authors: Schweiger Markus , Tannous Bakhos 
Published: November 2021

Abstract
Glioblastoma (GBM) is the most common primary malignant brain tumor and despite optimal treatment, long-term survival is extremely rare. Radiation therapy (RT) leads to successful initial tumor regression but recurrence is inevitable. Previous studies have shown that ionizing radiation leads to a change of immune-related markers on tumor cells. Extracellular vesicles (EVs) are membranous structures secreted by nearly every cell and have been shown drive GBM progression by acting as multifunctional signaling complexes. Here, we show that radiation of GBM cells leads to an altered EV secretion/uptake dynamic, composition, and protein content. Furthermore, we show that EVs secreted by radiated GBM cells modulate the innate (microglia/macrophages) as well as adaptive (T-cells) immune response in the tumor microenvironment. We dissected a novel mechanism by which GBM evades the immune system via EVs following RT, pointing towards novel therapeutic strategies to prevent GBM recurrence.
TAMI-47. MIR-542-3P CONTRIBUTES TO THE HK2-MEDIATED HIGH GLYCOLYTIC PHENOTYPE IN HUMAN GLIOMA CELLS
Authors: Kim Junhyung , Park Min Woo , Ahn Ju Won , Sim Jeong Min , Kim Suwan , Park Young Joon , Heo Jinhyung , Jeong Ji Hun , Lee Mihye , Lim Jaejoon , Moon Jong-Seok 
Published: November 2021

Abstract

BACKGROUND
The elevation of glucose metabolism is linked to high-grade gliomas such as glioblastoma multiforme (GBM). The high glycolytic phenotype is associated with cellular proliferation and resistance to treatment with chemotherapeutic agents in GBM. MicroRNA-542-3p (miR-542-3p) has been implicated in several tumors including gliomas. However, the role of miR-542-3p in glucose metabolism in human gliomas remains unclear.

METHODS
We measured the levels of cellular proliferation in human glioma cells. We measured the glycolytic activity in miR-542-3p knockdown and over-expressed human glioma cells. We measured the levels of miR-542-3p and HK2 in glioma tissues from patients with low- and high-grade gliomas using imaging analysis.

RESULTS
We show that knockdown of miR-542-3p significantly suppressed cellular proliferation in human glioma cells. Knockdown of miR-542-3p suppressed HK2-induced glycolytic activity in human glioma cells. Consistently, over-expression of miR-542-3p increased HK2-induced glycolytic activity in human glioma cells. The levels of miR-542-3p and HK2 were significantly elevated in glioma tissues of patients with high-grade gliomas relative to that in low-grade gliomas. The elevation of HK2 levels in patients with high-grade gliomas were positively correlated with the high levels of miR-542-3p in GBM and low-grade gliomas (LGG) based on the datasets from the Cancer Genome Atlas (TCGA) database. Moreover, the high levels of miR-542-3p were associated with poor survival rate in the TCGA database.

CONCLUSIONS
miR-542-3p contributes to the HK2-mediated high glycolytic phenotype in human glioma cells.
TAMI-50. PATHWAYS ACTIVATION IN GL261 MICE GLIOMA CELLS BY HIV-1 GLYCOPROTEIN GP120
Authors: Guillama Gabriel Valentín , Kucheryavykh Lilia 
Published: November 2021

Abstract
Patients infected with human immunodeficiency virus type 1 (HIV-1) are more prone to developing cancers, including glioblastomas (GBMs). The median survival for GBM patients with HIV is significantly shorter than for HIV-negative GBM patients, even though they receive the same treatments. This difference indicates that HIV infection is associated with more aggressive tumor behavior and with treatment resistance. Earlier we demonstrated that gp120, a main glycoprotein in the HIV shell, stimulates glycolysis and protein synthesis in glioma cells. The purpose of this study was to evaluate the underlying gp120 dependent signaling mechanism in glioma cell. Mouse glioma cells GL-261 were continuously cultured for 7 days in medium with and without soluble gp120 Bal III (100ng/ml) and collected for Western blot and Cell cycle assays. Western blot analysis presented an increase in phosphorylation of Proline-rich tyrosine kinase (Pyk2(Y402)), p38(YT100/Y182) and p70s6(T421/S424), the key proteins of the Pyk2 pathway, along with the increased levels of Akt(S473) and Glycogen Synthase Kinase 3b (GSK3b (S9)) phosphorylation. Flow cytometry analysis of Cell Cycle revealed an increase of G2/M phase in cells cultured in gp120 Bal III when compared to control cells. Furthermore, GL-261 cells with knock-out of Pyk2 via CRISPR Cas 9 gene editing showed no significant change in cell cycle regulation when cultured with gp120 Bal III.Overall, these results demonstrate that gp120 triggers activation of Pyk2/MAPK and Akt/GSK3b pathways and alter cell cycle regulation in GBM. This research was made possible by NIH grant number 1SC1GM122691.
TAMI-62. METHIONINE METABOLISM CLOSELY RELATED WITH SELF-RENEW, PLURIPOTENCY AND CELL DEATH IN GICS THROUGH MODIFICATION OF CHOLESTEROL BIOSYNTHESIS, RIBOSOMAL RNA AND AUTOPHAGY
Authors: Yokogami Kiyotaka , Takeshima Hideo 
Published: November 2021

Abstract
Glioma initiating cells (GICs) are the source of glioma cells that have the ability to self-renew and pluripotency, which are treatment-resistant, starting point for relapse and eventual death despite multimodality therapy. Since high accumulation is observed in 11cMet-PET at the time of recurrence, it is important to understand the mechanism of tumor cell activation caused by the reorganization of methionine metabolism. We cultured cells in methionine-deprived culture medium and performed a comprehensive analysis, and found that methionine depletion markedly decreased proliferation and increasing cell death of GICs. Decreased SAM, which is synthesized intracellularly catalyzed by methionine adenosyltransferase (MAT) using methionine, triggered the following: (i) global DNA demethylation, (ii) hyper-methylation of signaling pathways regulating pluripotentcy of stem cells, (iii) decreased expression of the core-genes and pluripotent marker of stem cells, (iv) decreased cholesterol synthesis and increased excretion mainly through decreased SREBF2 and FOXM1, (v) down-regulation of the large subunit of ribosomal protein configured 28S and ACA43, snoRNA guiding the pseudouridylation of 28S ribosomal RNA, which has crucial role for translation and (vi) possible connection between methionine metabolism and pluripotency, protein synthesis through cholesterol metabolism: SREBF2-FOXM1 and ACA43 axis, respectively. (vii) Disruption of autophagy by insufficient formation of macroautophagosomes. In conclusion, methionine metabolism closely related with self-renew, pluripotency and cell death in GICs through modification of cholesterol biosynthesis, ribosomal RNA and autophagy.