bluuebunny/crossref_metadata_2025_split huggingface dataset:
TAMI-49. JAK STAT INHIBITION REVERSES MYELOID CELL INDUCED ANTI TUMOR IMMUNITY IN T CELLS
Authors: Ravi Vidyha , Neidert Nicolas , Will Paulina , Joseph Kevin , Hofmann Ulrich , Beck Jürgen , Schnell Oliver , Heiland Dieter Henrik 
Published: November 2021

Abstract

BACKGROUND
Many central questions about the immunosuppressive microenvironment in glioblastoma (GBM) remain unanswered, particularly the interaction with lymphoid and myeloid populations. Here, we combined single-cell (scRNA) and spatial transcriptomics (stRNA) to comprehensively characterize the immune interaction with GBM.

MATERIAL AND METHODS
We performed scRNA-Seq of 50k CD45+ cells (8 patients) and inferred transcriptional programs and fate decisions in T cells. A novel algorithm (Nearest functionally connected neighbor) was used to predict interacting cells, further validated using spatial transcriptomics and immunofluorescence. Our findings were validated in our human neocortical glioblastoma model with autografted T cells.

RESULTS
Integration of st/scRNA-seq revealed a transcriptional shift of T cells towards exhaustion/hypoxia induced dysfunction. Pseudo-time analysis revealed increased Interleukin 10 (IL10) response during the Tcell transformation from the effector to the exhausted state. Using NFCN we identified a subset of HMOX1+ myeloid cells (STAT/HMOX axis), responsible for this IL10 release. Computational findings were validated using our human neocortical glioblastoma model with autografted T cells, where IL10R-inhibition/myeloid cell depletion prevented T cell exhaustion/dysfunction (p &lt; 0.01) . In order to target the STAT3/HMOX1 axis we used a JAK/STAT inhibitor in our model which showed a drastic reduction of IL10 release (p&lt; 0.02) and concordant activation of T cells. Clinically, one patient treated with a JAK/STAT-inhibitor in a neoadjuvant setting, 4 weeks prior to the recurrent GBM surgery, led to a significant increase (p&lt; 0.001) in effector T cell population.

CONCLUSION
Our findings suggest that targeting the myeloid compartment of GBM provides an opportunity to convert a “cold” into “hot” immune environment which might be helpful to improve all T cell based therapies in the future.
TAMI-51. HORIZONTAL MITOCHONDRIAL TRANSFER FROM THE TUMOR MICROENVIRONMENT TO GLIOBLASTOMA INCREASES TUMORIGENICITY
Authors: Watson Dionysios , Bayik Defne , Lathia Justin 
Published: November 2021

Abstract
Communication between glioblastoma (GBM) and its microenvironment facilitates tumor growth and therapeutic resistance, and is facilitated through a variety of mechanisms. Organelle transfer between cells was recently observed, including mitochondria transfer from astrocytes to neurons after ischemic stroke. Given the dependence of GBM on microenvironmental interactions, we hypothesized that mitochondria transfer from tumor microenvironment to GBM cells could occur and affect metabolism and tumorigenicity. We interrogated this in vivo by establishing intracranial GBM tumors in mito::mKate2 mice (with trackable fluorescent mitochondria) using syngeneic GFP-expressing tumor cells (SB28 and GL261 models). We also cultured stromal cell types from mito::mKate2 mice with tumor cells, enabling sorting of tumor cells with and without exogenous mitochondria. Confocal microscopy revealed horizontal transfer of mKate2+ mitochondria from mouse cells to implanted GBM cells in vivo and was confirmed by flow cytometry where 20-40% of GBM cells acquired exogenous mitochondria. Transfer was negligible in wildtype mice transplanted with mito::mKate2 bone marrow cells, suggesting that brain-resident cells were the main donors. In vitro, astrocytes and microglia exhibited 5 to 10-fold higher mitochondrial transfer rate than bone-marrow derived macrophages. Seahorse metabolic profiling revealed that GBM cells with mKate2+ mitochondria had 40% lower respiratory reserve compared to cells without exogenous mitochondria. Median survival of mice implanted with SB28 that acquired mitochondria was significantly shorter and in vivo limiting dilution confirmed the frequency of tumor-initiating cells was 3-fold higher in SB28 cells with exogenous mitochondria. Our data indicate that horizontal mitochondrial transfer from brain-resident glia to mouse GBM tumors alters tumor cell metabolism and increases their tumorigenicity. Ongoing studies are assessing gene expression in GBM cells acquiring exogenous mitochondria; validating findings in human specimens; and screening for transfer inhibitor drugs. Horizontal mitochondrial transfer represents a foundational tumor microenvironment interaction contributing to glioblastoma plasticity, and is likely to inform next-generation treatment strategies.
TAMI-52. NEURONAL MECHANISMS OF BRAIN TUMOR INVASION
Authors: Venkataramani Varun , Yang Yvonne , Schubert Marc , Beretta Carlo , Botz Michael , Fankhauser Laura , Tetzlaff Svenja , Wagner Julia , Garofano Luciano , Freudenberg Alexander , Slowik Martin , Tanev Dimitar , Döring Leif , Iavarone Antonio , Wick Wolfgang , Kuner Thomas , Winkler Frank 
Published: November 2021

Abstract
Incurable gliomas are characterized by their infiltration into the whole brain. Recently, we described tumor microtubes as a novel structure contributing to glioma cell invasion and uncovered synaptic contacts on glioma cells that drive brain tumour progression. However, the exact effects of neuronal activity on glioma cell motility are yet unclear. Here, we show how a recently described neuronal-like cellular transcription state of glioblastoma cells is correlated to glioma cell invasion in vivo. To unravel the details of neuronal features of glioma invasion in space and time, we established a novel approach of intravital imaging for brain tumor cells with a membrane-bound GFP combined with deep learning algorithms that are used to track glioma cell processes with a high temporal resolution over several hours. This approach uncovers how invading tumor microtubes use Levy-like movement patterns indicative of efficient search patterns often employed by animal predators searching for scarce resources such as food. Neuronal activity is able to accelerate the tumor microtube dynamics, accelerate the Levy-like movement patterns and increase the overall invasion speed of glioma cells. These processes are mediated by local calcium transients in glioma cell somata and tumor microtubes. In accordance, genetic manipulation and pharmacological perturbation of AMPA receptors reduces tumor microtube length, number and branching points by interfering with intracellular calcium transients. All in all, the work here uncovers novel neuronal activity-mediated mechanisms of glioma cell invasion, a hallmark of this yet fatal disease.
TAMI-60. MODULATION OF CELL BIOMECHANICS THROUGH GUIDANCE RECEPTOR PLEXIN-B2 FACILITATES GLIOBLASTOMA INFILTRATION
Authors: Friedel Roland , Huang Yong , Tejero Rut , Alves Chrystian Junqueira , Brusco Concetta , Hannah Theodore , Lee Vivian , Dai Guohao , Zou Hongyan 
Published: November 2021

Abstract
Infiltrative growth is a major cause of the high lethality of malignant brain tumors such as glioblastoma (GBM). The study of the contribution of biomechanical processes to GBM invasion is an emerging field. We show here that GBM cells upregulate the guidance receptor Plexin-B2 to gain invasiveness by modulating their biomechanical properties. Deletion of Plexin-B2 in GBM stem cells limited tumor spread and shifted invasion paths from axon fiber tracts to perivascular routes. On a cellular level, Plexin-B2 adjusts cell adhesiveness, migratory responses to different matrix stiffness, and actomyosin dynamics, thus empowering GBM cells to leave stiff tumor bulk and infiltrate softer brain parenchyma. Correspondingly, gene signatures affected by Plexin-B2 were associated with locomotor regulation, matrix interactions, and cellular biomechanics. On a molecular level, the intracellular Ras-GAP domain contributed to Plexin-B2 function, while the signaling relationship with downstream effectors Rap1/2 appeared variable between GBM stem cell lines, reflecting intertumoral heterogeneity. Our studies have established Plexin-B2 as a modulator of cell biomechanics that is usurped by GBM cells to gain invasiveness. Ongoing investigations focus on the regulation of the biomechanical properties of cell membrane and cell actomyosin cortex through plexins that provide GBM cells with the mechanical dynamics to penetrate to restricted space.
TAMI-64. IMMUNE ENVIRONMENT SHAPES GLIOBLASTOMA HETEROGENEITY IN TIME AND SPACE
Authors: Will Paulina , Kückelhaus Jan , Benotmane Jasim Kada , Joseph Kevin , Beck Jürgen , Schnell Oliver , Ravi Vidyha , Heiland Dieter Henrik 
Published: November 2021

Abstract
Glioblastomas are embedded into an immunosuppressive microenvironment resulting in limited success of immunotherapies. Although, we and others observed defined myeloid-tumor crosslinks reducing T cell homing and activation, the spatial context of these interactions remained unexplored. Here, we provide evidence, that local T cell infiltration results in a defined activation of myeloid cells causing transcriptional reprogramming of tumor cells reminiscent of reactive transformation in mature astrocytes. Through integration of spatially resolved transcriptomics and imaging mass cytometry (n=18, 39 protein glioma panel) we mapped defined transcriptional responses in areas of high or low T cell infiltration respectively. Functional analysis revealed that areas of large T cell infiltration are enriched for glial (CHI3L1, GFAP and VIM) and inflammatory genes (HLA-DRA, C3, CCL4, CCL3). We found that marker genes of common reactive states in mature astrocytes significantly overlap with the reactive immune program of glioblastoma cells (f-score 0.76, p=2.2e-10). Increased numbers of CD163+ cells were found in surrounding areas of T cell infiltration and spatially linked to defined immunosuppressive release of IL10, recently reported as a major driver of T cell exhaustion. To support our findings, we injected a primary glioblastoma cell line into cortex slices of three different human and rodent donors. After 7 days of tumor growth, we performed scRNA-sequencing of FACS-sorted tumor cells and baseline cell culture cells. Compared to baseline, we found cells of all reported transcriptional states, confirming the dynamic adaptation of cells within a neural environment. In elderly donors, a significant accumulation of reactive immune programs (ANOVA p&lt; 0.001) was observed. Immunostainings confirmed an increased myeloid cell activation in these donors. Our data suggest that inflammatory stimuli in the glioblastoma microenvironment cause transcriptional reprogramming in glioblastoma similar to inflammatory transformation of reactive astrocytes. The spatial exclusivity of these programs highlights the value of a spatial perspective on heterogeneity.
TAMI-65. FASN-MEDIATED LIPID SYNTHESIS HAMPERS ANTI-CANCER IMMUNITY OF GLIOBLASTOMA
Authors: De Martino Mara , Daviaud Camille , Vanpouille-Box Claire 
Published: November 2021

Abstract
Glioblastoma (GBM) is the most aggressive type of primary brain tumor in adults. Radiation therapy (RT) is an essential modality for GBM treatment and is recognized to stimulate anti-cancer immunity by at least generating type I interferon (IFN-I) responses. However, RT also exacerbates potent immune inhibitory mechanisms that facilitate immune evasion. Notably, increased lipid synthesis by the fatty acid synthase (FASN) is an emerging mechanism that can account for the deceiving treatment efficacy and immune escape of GBM. Therefore, we hypothesize that FASN-mediated lipid synthesis represents an innate immune evasion mechanism of irradiated GBM. Supporting this hypothesis, we observed that 10 gray (Gy) irradiation of murine GBM cell lines, GL261 and CT2A, upregulates FASN protein expression and increase cellular lipid content determined by BODIPY staining and electronic microscopy. Interestingly, this effect was abrogated when GBM cells were incubated with an inhibitor of FASN. Next, to ask whether FASN was impairing RT-induced IFN-I, GL261 and CT2A cells were engineered to express an inducible shRNA silencing FASN (GBMshFASN) or its non-silencing control (GBMshNS). Irradiation of GBMshNS cells enhanced the secretion of IFN-beta and CXCL10, but this effect was more pronounced when FASN was blocked. Finally, GBMshNS and GBMshFASN cells were orthotopically implanted in mice on day 0. On day 10, selective irradiation (10Gy) was performed to the tumor. Tumor growth and immune contexture were evaluated on day 17. Magnetic resonance imaging revealed that FASN knockdown reduces tumor growth independently from RT. However, in situ immunofluorescence of GBMshFASN tumors showed increased infiltration of CD8+ T cells and CD11c+ cells only in irradiated mice bearing GBMshFASN tumors. Altogether, our data suggest that RT rewires the energy supply of GBM by promoting FASN-mediated lipid synthesis to foster immune evasion. Targeting FASN is a promising strategy to promote anti-cancer immunity and sensitize irradiated GBM to immunotherapies.
TAMI-66. FUNCTIONAL ALTERATIONS IN CORTICAL PROCESSING OF SPEECH IN GLIOMA-INFILTRATED CORTEX
Authors: Aabedi alexander , Lipkin Benjamin , Kaur Jasleen , Kakaizada Sofia , Young Jacob , Lee Anthony , Krishna Saritha , Chang Edward , Brang David , Hervey-Jumper Shawn 
Published: November 2021

Abstract

INTRODUCTION
Recent developments in the biology of malignant gliomas have demonstrated that glioma cells interact with neurons through both paracrine signaling and electrochemical synapses. Glioma-neuron interactions consequently modulate the excitability of local neuronal circuits, and it is unclear the extent to which glioma-infiltrated cortex can meaningfully participate in neural computations. For example, gliomas may result in a local disorganization of activity that impedes the transient synchronization of neural oscillations. Alternatively, glioma-infiltrated cortex may retain the ability to engage in synchronized activity, in a manner similar to normal-appearing cortex, but exhibit other altered spatiotemporal patterns of activity with subsequent impact on cognitive processing.

METHODS
Here, we acquired invasive electrophysiologic recordings to sample both normal-appearing and glioma-infiltrated cortex during speech initiation in order to measure language task-related circuit dynamics of IDH-wild-type glioblastoma patients. We then applied an information theoretical framework to directly compare the encoding capacity and decodability of signals arising from these regions.

RESULTS
We find that glioma-infiltrated cortex engages in synchronous activity during task performance in a manner similar to normal-appearing cortex, but recruits a diffuse spatial network. On a temporal scale, we show that glioma-infiltrated cortex has lower capacity for information encoding when performing nuanced tasks such as speech production of monosyllabic versus polysyllabic words. As a result, temporal decoding strategies for distinguishing monosyllabic from polysyllabic words were feasible for signals arising from normal-appearing cortex, but not from glioma-infiltrated cortex.

CONCLUSION
These findings inform our understanding of cognitive processing in patients with malignant gliomas and have implications for patient survival, neuromodulation, and prosthetics in patients with malignant gliomas.
TAMI-70. METABOLIC VULNERABILITY TO GPX4 INHIBITION AND FERROPTOSIS OF QUIESCENT ASTROCYTE-LIKE GLIOMA CELL POPULATIONS
Authors: Banu Matei , Dovas Athanassios , Argenziano Michael , Zhao Wenting , Higgins Dominique , Upadhyayula Pavan , Mahajan Aayushi , Humala Nelson , Nguyen Trang , Zandkarimi Fereshteh , Siegelin Markus D , Brent Stockwell , Sims Peter , Bruce Jeffrey N , Canoll Peter 
Published: November 2021

Abstract
Diversity is a key feature in the glioma ecosystem. Adaptation to a changing tumor microenvironment is achieved through cellular and metabolic plasticity. Here we show that slow-cycling, astrocyte-like glioma cell subpopulations activate distinct metabolic programs, rendering them susceptible to novel treatments. We performed multi-omics analysis on transgenic murine glioma models to characterize cellular heterogeneity. Bulk RNAseq on targeted time-dependent biopsies combined with scRNAseq uncovered distinct tumor cell populations, including a quiescent, astrocyte-like population relatively insensitive to conventional chemotherapy targeting proliferating cells. Using scRNAseq, we identified a persistently conserved astrocytic population in human IDH1-mt/wt high-grade gliomas. This astrocytic tumor population was more abundant in mouse models with constitutive Notch activation, however it was associated with alterations in several other transcriptional programs, suggesting that targeted therapies would likely be ineffective at eradicating it. Gene ontology analysis revealed enrichment in mitochondrial genes specifically regulating oxidative phosphorylation and tricarboxylic acid cycle. Energetic, lipidomic and metabolomic analyses revealed significant mitochondrial β-fatty acid oxidation and lipid catabolism, with less effective oxygen consumption rate and higher basal oxidative stress. Furthermore, this astrocytic tumor population had depleted levels of basal GSH and was more sensitive to reactive oxygen species. Leveraging this metabolic vulnerability, we performed drug screens and found that therapeutic inhibition of complex I or GPX4 was highly effective and synergistic. GPX4 inhibition induced ferroptosis, a newly-discovered form of programmed non-necroptotic cell death mediated by iron-driven lipid peroxidation. Using scRNAseq and RNAscope on ex vivo slice cultures from murine and human gliomas, we found that GPX4 inhibition and ferroptosis induction in the glioma microenvironment selectively eradicated the quiescent astrocytic subpopulation whereas proliferating glioma were less sensitive. Our data therefore supports a novel treatment paradigm, employing metabolic strategies, such as ferroptosis, in conjunction with chemotherapy and RT to target distinct tumor cell populations with different therapeutic vulnerabilities.
TAMI-77. CHARACTERIZATION OF METABOLIC DIFFERENCES IN MENINGIOMAS USING TUMOR TISSUE AND PATIENT-DERIVED CELL LINES
Authors: Rabow Zach , Morningstar Taryn , Fiehn Oliver , Lechpammer Mirna 
Published: November 2021

Abstract
As more information emerges on metabolic changes in brain pathologies, mass spectrometry methodologies are needed to investigate cellular changes in primary brain tumors. Many approaches use technologies that lack sensitivity and selectivity, which hinders discovering potential novel diagnostic and prognostic features. Fresh frozen tissue from 26 patients (57% women, 43% men, age 21-67) underwent surgical resection for newly diagnosed meningiomas. We used patient-derived cell lines and arachnoid cells to validate and compare metabolic differences in patient tumor tissue. Primary metabolism (GC-TOF), lipidomics, and biogenic amines (RPLC and HILIC-HRMS) were analyzed using 10 mg of tissue and 1x106 cells. RESULTS: Primary metabolism and lipidomics showed significant differences between Grade I and Grade II tumors. We identified over one thousand total metabolites through authentic standards and MS2 fragmentation patterns. Ascorbic Acid was enriched in Grade I tumors compared to Grade II and enriched in tumors compared to non-neoplastic dura tissue from the same patient. Lysosomal activation in atypical meningiomas is indicated by a 2-fold increase (compared to Grade I tumors) of Bis(monoacylglycero)phosphate metabolites. We grouped metabolites into fifteen classes based on chemical ontology and function. Statistically significant differences were observed in total amino acids (AA), basic AA, cyclic AA, sulfur-containing AA, branched-chain AA, dipeptides, histidine-containing dipeptides, vitamins and cofactors, glutathione metabolites, acylcarnitine’s, sphingomyelins, phosphatidylethanolamines, phosphatidylinositol’s, cardiolipins, and nucleic acids. Thymine-containing nucleic acids and biogenic monoamines were 2-fold higher in Grade I compared to Grade II tumors. Using novel untargeted metabolomics, we found multiple classes of metabolites that were enriched in Grade II meningiomas compared to Grade I. This points towards possible pathways that drive malignancy and biomarkers that could be useful for diagnosis, grading, and treatment selection.
TAMI-79. THERAPEUTIC REVERSAL OF PRENATAL PONTINE ID1 SIGNALING IN DIPG
Authors: Yadav Viveka Nand , Harris Micah K , Messinger Dana , Thomas Chase , Cummings Jessica R , Yang Tao , Woo Rinette , Siddaway Robert , Burkert Martin , Stallard Stefanie , Qin Tingting , Mullan Brendan , Siada Ruby , Ravindran Ramya , Niculcea Michael , Ginn Kevin F , Gener Melissa A H , Dorris Kathleen , Vitanza Nicholas A , Schmidt Susanne V , Spitzer Jasper , Li Jiang , Filbin Mariella G , Cao Xuhong , Castro Maria G , Lowenstein Pedro R , Mody Rajen , Chinnaiyan Arul , Desprez Pierre , McAllister Sean , Hawkins Cynthia , Waszak Sebastian M , Venneti Sriram , Koschmann Carl 
Published: November 2021

Abstract
Diffuse intrinsic pontine glioma (DIPG) is a highly aggressive pediatric brain tumor with rare survival beyond two years. This poor prognosis is largely due to the tumor's highly infiltrative and invasive nature. Nearly 80% of DMGs harbor K27M mutation in the genes encoding histone H3.1 (H3F3A) or H3.3 (HISTIH3B), often with concurrent ACVR1 mutation. Inhibitor of DNA-binding (ID) proteins are key transcriptional regulators of genes involved in lineage commitment and are associated with invasiveness and poor clinical outcomes in multiple human cancers. Introduction of H3K27M and ACVR1 mutations increase ID1 expression in cultured astrocytes, but this has not been confirmed in human tumors or targeted therapeutically. We developed an in-utero electroporation (IUE) murine H3K27M-driven tumor model, which demonstrates increased ID1 expression in H3K27M- and ACVR1-mutated tumor cells. Exome and transcriptome sequencing analysis of multi-focal DMG tumors (n=52) and normal brain tissue revealed that increased ID1 expression is associated with H3K27M/ACVR1-mutation and brainstem location, and correlates with poor survival in patients. ChIP-sequencing for H3K27ac and H3K27me3 in multiple DMG tumors (n=5) revealed that the ID1 gene is epigenetically active, which matches the epigenetic state of murine prenatal hindbrain cells. Higher ID1-expressing astrocyte-like DIPG cells share a similar transcriptional program with ID1+/SPARCL1+ positive oligo/astrocyte-precursor (OAPC) cells from the developing human brain and demonstrate upregulation of gene sets involved in regulation of cell migration. Both genetic and pharmacologic [cannabidiol (CBD)] suppression of ID1 result in decreased DIPG cell invasion/migration in vitro and invasion/tumor growth in multiple in vivo models. Mechanistically, CBD reduces proliferation through production of reactive oxygen species. Further, DIPG patients treated off-trial with CBD (n=15) displayed reduced ID1 tumor expression and improved overall survival. In summary, ID1 is upregulated in DIPG through K27M-mediated epigenetic reactivation of a developmental OAPC-like transcriptional state, and ID1-driven invasiveness of DIPG is therapeutically targetable with CBD.