bluuebunny/crossref_metadata_2025_split huggingface dataset:
IMMU-17. ADENOSINE DEAMINASE ACTING ON RNA (ADAR) SILENCES TUMOR-INTRINSIC INTERFERON RESPONSE IN DIFFUSE MIDLINE GLIOMA
Authors: Ramsoomair Christian , Castro Jesus , Seetharam Deepa , Shah Ashish , Reinberg Danny 
Published: November 2024

Abstract

INTRODUCTION
Diffuse midline glioma (DMG) is the most aggressive primary brain tumor in children and is currently incurable. Clinical trials using immune checkpoint blockade (ICB) therapy have failed to show efficacy due to multifactorial mechanisms including limited lymphocyte infiltration, low immune checkpoint (IC) expression, and a low mutational burden. Adenosine deaminase acting on RNA (ADAR) is an RNA editor, which limits anti-tumor immunity by editing/preventing the sensing of endogenous double-stranded RNA (dsRNA). We have found that ADAR protein levels are significantly elevated in DMG patients, suggesting that ADAR’s immune-silencing function is relevant to DMG immune suppression. The onco-histone driver H3K27M promotes epigenetic dysregulation in DMGs, de-suppressing retroelement transcription, a major source of endogenous dsRNA. By inhibiting ADAR, we expect that the increased levels of dsRNA will stimulate intracellular type-1 interferon (IFN) responses, induce chemokine secretion, and promote antitumor CD8+ cytotoxicity.

METHODS
Human DMG cells and patient-derived glioma spheres were treated with silencing RNA to transiently knockdown (KD) ADAR levels for assays involving in vitro viability and proliferation. Affected pathways were identified using immunoblotting and quantitative PCR.

RESULTS
Our data shows that ADAR protein levels are elevated in DMG patient proteomic datasets and cell lines. ADAR-depleted patient-derived DMG cell lines exhibit significantly less proliferation compared to control siRNA and ADAR-depleted hTERT-astrocytes (Mann-Whitney test, P-value &lt;0.0001, ****).

CONCLUSION
Our results demonstrate that DMG tumor cells have an ADAR selective dependency in vitro. In ongoing studies, we aim to determine if ADAR-depletion improves in-vivo survival in both immunodeficient and immunocompetent models in combination with immunotherapies against DMG.
IMMU-18. IL-7 MEDIATED UPREGULATION OF VLA-4 INCREASES ACCUMULATION OF ADOPTIVELY TRANSFERRED T LYMPHOCYTES IN MURINE GLIOMA
Authors: Singh Kirit , Hotchkiss Kelly , Cook Sarah , Noldner Pamy , Zhou Ying , Moelker Eliese , Railton Chelsea , Blandford Emily , Puviindran Bhairavy , Wallace Shannon , Norberg Pamela , Archer Gary , Shaz Beth , Sampson John , Khasraw Mustafa , Fecci Peter 
Published: November 2024

Abstract
We have previously described the development of a novel brain bi-specific T cell engager (BRiTE) targeting EGFRvIII in Glioma. Despite BRiTEs impressive potency, efficacy in solid tumors is dependent on tumor-infiltrating lymphocytes (TILs). We evaluated if peripheral adoptive lymphocyte transfer (ALT) increases TILs in immunocompetent mice, even during glioma-induced sequestration. C57/Bl6 mice were implanted with 3 x 10^4 cells syngeneic glioma (CT-2AvIII) and treated with 1 x 10^7 IV CD45.1+ ALT on Day 15. The brain was divided into tumor and non-tumor bearing hemispheres and analyzed each day for exogenous (CD45.1+) CD3/4/8 counts. We observed that IL-7-expanded ALT accumulated at a higher rate within tumor versus IL-2 ALT (72-hours IL-7 median 26.66x vs IL-2 median 4.291x, p=0.0159*). Exogenous T cell entry into tumor-bearing CNS overwhelmingly consisted of CD8+ T cells, and CD45.1+ IL-7 ALT cells made up ~20% of the CD3+ population in tumor 72-hours following administration (mean 19.4%, SD ±4.53%, n=5). Survival experiments used combination ALT and anti-4-1BB therapy in the same model. Mice were treated with IV ALT on Day 5, along with 200µg of IP anti-4-1BB. IP mAb Injections were given every 3 days for 4 total cycles (D5, D8, D11 & D14). Evaluation at these time points was selected as this correlated with peak sequestration of immune cells as evidenced by splenic involution. For survival studies, only combination ALT and anti-4-1BB produced significantly increased survival benefit in our CT-2AvIII model compared to ALT alone (median survival 45.5 days for combination versus 25 days in ALT only group, p=0.0134, chi-square test). These findings demonstrate the feasibility of combination ALT/antibody-based therapy in pre-clinical glioma, as well as outlining a novel approach for delivering both immune cells and antibody-based immunotherapy. Combination therapy with BRiTE and ALT will be explored in an upcoming clinical trial (NCT04903795).
IMMU-20. CIRCULATING CELL-FREE DNA DIRECTLY INHIBITS T CELL RESPONSES AND CONTRIBUTES TO SYSTEMIC IMMUNOSUPPRESSION IN GLIOBLASTOMA
Authors: Hoyt-Miggelbrink Alexandra , Reesman Rachael , Anani-Wolf Delaney , Hansen Michael , Pfaller Christian , Fain Cori , Johnson Aaron , Ayasoufi Katayoun 
Published: November 2024

Abstract
Glioblastoma (GBM) is an aggressive form of brain cancer with poor survival despite standard of care. Checkpoint inhibitors aimed to revive dysfunctional T cells have significantly improved outcomes in other cancers, but have failed GBM. GBM patients have severe peripheral immunosuppression, including severe lymphopenia, immune organ atrophy, and defective T cell responses. This immunosuppression is a critical barrier to patient survival and the success of immunotherapies. Using parabiosis, we demonstrated that serum-derived factors were sufficient to drive hallmark features of immunosuppression, including inhibition of ex vivo T cell proliferation. This factor was nonsteroidal in nature and had molecular weights greater than 100kDa. Mass-spectrometry and pathway analysis of the suppressive serum implicated proteins involved in DNA response elements, cell death, and DNA-histone complexes. We hypothesized that the factor is cell-free DNA (cfDNA). Confirming this, serum levels of cfDNA are increased in glioma-bearing mice. Moreover, exposure to cfDNA from serum of glioma-bearing mice was sufficient to directly and potently inhibit T cell proliferation ex vivo. Interestingly, exposure to genomic DNA was not sufficient to induce proliferation defects in T cells, highlighting the unique features of cfDNA. Importantly, reducing cfDNA content using DNaseI partially restored proliferation capacity. We determined that the T cell proliferation defects were independent of DNA sensing mechanisms through AIM2, implicating a novel pathway of DNA sensing in T cells. Finally, to determine the origin of the cfDNA, we employed methyl-seq. The chromatin signature most closely represented neutrophils. This highlights a potential role for neutrophils-derived cfDNA as a targetable strategy in GBM. Together, we contend that cfDNA induces immunosuppressive effects in GBM and devising strategies to reduce circulating cfDNA could be a therapeutic approach to improve T cell functions and outcomes in GBM patients.
IMMU-21. OVEREXPRESSING CAR T-CELL GLUCOSE TRANSPORTER TO ENHANCE ANTI-TUMOR ACTIVITY IN GLIOBLASTOMA
Authors: Sengupta Srabasti , Jin Linchun , Feier Diana , Silver Aryeh , Chakraborty Avirup , Tao Haipeng , Thomas Nagheme , Rahman Maryam , Flores Catherine , Castillo Paul , Sarkisian Matthew , Huang Jianping , Mitchell Duane A , Deleyrolle Loic P 
Published: November 2024

Abstract

INTRODUCTION
Despite aggressive interventions, Glioblastoma (GBM) remains as a challenge for neuro-oncologists. Standard treatments are often followed by disease recurrence. Adoptive cell therapies have emerged as a viable therapeutic for brain malignancies. CAR-T cell therapy has generated substantial interest because of its efficacy and specificity in treating various cancers. Despite these efficacies, studies reveal limitations of CAR-T therapy due to the altered metabolic environment in GBM. GBM tumors shift towards aerobic glycolysis, regardless of oxygen availability leading to massive glucose consumption. This results in impeding T-cell glycolysis and activation.

OBJECTIVE
The GBM microenvironment provides local restraints via metabolic competition suppressing antitumor immunity, specifically inhibiting infiltration and tumoricidal functions of host and adoptively transferred tumor-reactive T-cells. In our study, we manipulated the metabolic fitness of the therapeutic T-cells to enhance their tumoricidal activity, by overexpressing glucose transporter GLUT1 and GLUT3. We show that this manipulation can enhance their anti-tumor activity.

METHODS
The T-cell glucose metabolic pathway was modulated via glucose transporter overexpression. The functionality of metabolically modified T-cells was investigated in murine and human models.

RESULTS
We demonstrated that tumor cells impose glucose restriction when competing for glucose with T-cells leading to T-cell hypo responsiveness. Overexpression of glucose transporters such as Glut1 and Glut3 increased T-cell glucose utilization and provide survival advantage leading to enhanced T-cell activation in glucose-restricted conditions. The metabolic modifications regulate T-cell efficacy by enhancing intra-tumoral trafficking. We tested this approach in the context of CD70CAR T cell therapy. It was established that glucose transporter overexpression in CD70 CAR T-cells not only improves intracranial tumor invasion but also elicit functional anti-tumor cell response thus improving survival.

CONCLUSIONS
This study integrates fundamental concepts of tumor and immune metabolism in the design of immunotherapy and confirms that immunometabolism represents a viable target for new cancer therapy to treat brain tumors.
IMMU-25. B-CELL BASED THERAPY (BVAX) PRODUCES ANTIBODIES TO SUPPRESS GLIOBLASTOMA TUMOR MIGRATION AND INVASION
Authors: Katz Joshua , Castro Brandyn , Wang Si , Arrieta Victor , Najem Hinda , Vazquez-Cervantes Gustavo Ignacio , Olson Ian , Hou David , Dapash Mark , Wan Hanxiao , Rashidi Aida , Arjmandi Tarlan , Shaikh Zainab , Jones Grace , Platanias Leonidas , McCortney Kathleen , Horbinski Craig , Stupp Roger , Zhang Peng , Ahmed Atique , Sonabend Adam , Heimberger Amy , Lesniak Maciej , Riviere-Cazaux Cécile , Burns Terry , Miska Jason , Fischietti Mariafausta , Lee-Chang Catalina 
Published: November 2024

Abstract
Glioblastoma (GBM) presents as a highly aggressive and malignant brain tumor with limited treatment options. Despite the availability of existing therapies, the invasive characteristics of GBM frequently result in tumor recurrence and poor prognosis. We previously developed a B-cell-based therapy (BVax) that has shown promising results in its ability to induce therapeutic responses in preclinical models of GBM. Our research revealed potency of BVax can be attributed to its robust antigen-presenting capability, cognate antigen specificity with T cells, and ability to generate tumor-reactive antibodies. The present study aims to characterize the unique antigenic reactivity of BVax-derived antibodies by evaluating their immunological effects and therapeutic potential in both murine models and GBM patient-specific samples. Leveraging CD45.1 and CD45.2 congenic mouse models, we first revealed that BVax preferentially migrated to glioma-bearing brains upon intravenous injection, resulting in a CD38+CD20-CD19+ plasmablast phenotype. To further characterize the reactivity of BVax-derived immunoglobulins (Ig), we utilized proteomic analysis and identified preferential targets of Gelsolin, Fibronectin, Versican, Fibrinogen, and collagen type IV alpha, commonly associated with cell motility and the extracellular matrix. Microdialysis data confirmed the increased presence of many of these BVax-derived Igs-recognized antigens in tumor regions compared to normal brain regions in GBM patients. Utilizing purified BVax-derived antibodies from patient specimen, in vitro cell motility assays demonstrated a significant prevention of the invasion and migration of cell lines from patient derived xenograft (PDX). In this study, we concluded that BVax elicits antitumor activity through targeted migration to tumor-bearing regions, differentiation into plasmablasts, and robust secretion of specific Igs that retain the ability to inhibit functionalities associated with cell invasion and migration. Here, we present the first in-depth study that characterizes GBM patients’ antibody reactivity, specifically a subset of inflammatory B cells (BVax) with therapeutic effects that offer an indication for a new direction of immunotherapies.
IMMU-27. INHIBITION OF THE EXTRACELLULAR MATRIX PROTEIN EFEMP1/FIBULIN-3 REDUCES IMMUNOSUPPRESIVE SIGNALING IN TUMOR STEM CELLS AND INCREASES MACROPHAGE ACTIVATION AGAINST GLIOBLASTOMA
Authors: Kundu Somanath , Mitra Soham , Arivazhagan Roshini , Longo John , Longo Sharon , Venskus Abigail , Babu Harish , Viapiano Mariano 
Published: November 2024

Abstract
Glioblastoma tumors remain a formidable challenge for immune-based treatments because of their molecular heterogeneity, poor immunogenicity, and growth in the largely isolated and immunosuppresive neural environment. As the tumor grows, GBM cells change the composition and architecture of the neural extracellular matrix (ECM), affecting the mobility, survival, and function of immune cells such as tumor-associated microglia and infiltrated macrophages (TAMs). We have previously described the unique expression of the ECM protein EFEMP1/fibulin-3 in GBM compared to normal brain and demonstrated that this secreted protein promotes growth and resistance of the GBM stem cell (GSC) population. Here, we describe a novel immunomodulatory role of fibulin-3 and the immuno-boosting effects of targeting this ECM protein. Mice carrying fibulin-3-deficient intracranial tumors showed increased myeloid infiltration and reduced expression of TAM pro-tumoral markers (Arginase, CD206) compared to controls. The opposite was observed in orthotopic tumors overexpressing fibulin-3. In silico dataset analysis revealed positive correlation of fibulin-3 with an immunosuppresive signature in GBM, which was validated in GBM stem cells (GSCs). Accordingly, expression of fibulin-3 by GSCs promoted anti-inflammatory polarization of co-cultured macrophages. We further demonstrated that fibulin-3 regulated the expression of immunosuppresive signals (CSF-1, TGFbeta) and the innate immune checkpoint CD47 in GSCs via autocrine activation of NF-kB signaling. Immunosuppresive signals in GSCs were downregulated by knockdown of fibulin-3 or inhibition of this protein with an anti-fibulin-3 antibody (mAb428.2). Genetic or antibody-mediated targeting of fibulin-3 in GSCs co-cultured with macrophages (U937 and THP1 lines) increased macrophage phagocytosis and reduced the viability of the tumor cells. Furthermore, local delivery of mAb428.2 in mice carrying intracranial GBM resulted in increased infiltration of TAMs expressing pro-inflammatory markers and reducing tumor viability. Our findings show that anti-fibulin-3 approaches, which impact the tumor ECM, can diminish immunosuppression in GBM and boost innate immune responses against the tumor.
IMMU-28. LOW-INTENSITY PULSED ULTRASOUND COMBINED WITH POLY-ICLC AND INTERLEUKIN-2 UNLOCKS THE IMMUNE PRIVILEGE OF THE BRAIN BY PROMOTING EPITOPE SPREADING AND ACTIVATION OF CNS-SPECIFIC NAÏVE T CELLS
Authors: Gallus Marco , Yamamichi Akane , Arrieta Victor Andres , Saijo Atsuro , Chuntova Pavlina , Phyu Su , Phung Lan , Haegelin Jeffrey , Long Haoyu , Lakshmanachetty Senthilnath , Nejo Takahide , Okada Kaori , Chen Li , Habashy Karl , Gould Andrew , Amidei Christina , Chang Catalina Lee , Stupp Roger , Canney Michael , Sonabend Adam M , Okada Hideho 
Published: November 2024

Abstract
Immunotherapies targeting glioma, such as chimeric antigen receptor (CAR) T cell therapies, offer new therapeutic avenues; however, their application has yielded limited success in clinical trials so far. Due to the antigenic heterogeneity of gliomas, targeting a few or several antigens still results in recurrence with “antigen-loss” tumors, indicating the need to engage the endogenous immune system to eliminate these therapy-resistant tumor cells. However, natural anatomical barriers and an immunosuppressive environment allow brain tumors to evade detection by the endogenous immune system. Low-intensity pulsed ultrasound combined with microbubbles (LIPU/MB) has recently been shown to transiently open the blood-brain barrier (BBB), enabling penetration of cells and drugs into the CNS. Using intravital two-photon imaging, two-photon microscopy, multiparametric spectral flow cytometry, and bone marrow chimera mice, alongside blood samples from glioblastoma patients treated with LIPU/MB, we observed that LIPU/MB promotes migration of CNS antigen-presenting cells from the perivascular space into the periphery. To assess the immunological relevance of LIPU/MB-mediated CNS antigen presentation to the peripheral immune system, we have developed new transgenic mice (GFAP-minigene mice) with an intact BBB expressing four immunogenic peptides under the CNS-specific GFAP promoter. In GFAP-minigene mice, LIPU/MB combined with toll-like receptor 3 agonist poly-ICLC and Interleukin-2 promoted priming, activation, and homing of naïve CNS-specific T cells into the brain parenchyma. Cytotoxic T cell activity in the brain was accompanied by MHC-I and MHC-II epitope spreading, mirrored by the occurrence of endogenous T cells in the brain, deep cervical lymph nodes, and spleen harboring other CNS-(minigene) antigen-specific T cell receptors. Collectively, our findings suggest that LIPU/MB combined with poly-ICLC can overcome inherent limitations of immunotherapy by enhancing CNS epitope spreading and activation of naïve CNS-antigen-specific T cells within the context of an intact blood-brain barrier.
IMMU-35. TARGETING THE AHR IMMUNOMETABOLIC HUB DURING VIROIMMUNOTHERAPY OF GLIOMAS
Authors: Lopez-Rivas Andres R , Gillard Andrew G , Parthasarathy Akhila , Shin Dong H , Garcia-Moure Marc , Hampton Lethan A , He Jiasen , Jiang Hong , Fan Xuejun , Wainwright Derek , Quintana Francisco J , Fueyo Juan , Gomez-Manzano Candelaria 
Published: November 2024

Abstract
Glioblastoma (GBM) poses a significant therapeutic challenge in oncology. Recent clinical trials have shown the feasibility of virotherapy to treat patients with GBM. Our laboratory developed an oncolytic adenovirus termed Delta-24-RGD that has been tested in clinical trials for recurrent GBM patients with encouraging results (NCT00805376, NCT02798406). These clinical studies, together with preclinical data, showed that the efficacy of Delta-24-RGD was due to direct tumor cell oncolysis and indirect activation of anti-tumor immune response. To further leverage this immune component, our group generated Delta-24-RGDOX, an armed version of Delta-24-RGD expressing the T-cell activator OX40-L, which exhibits a superior anti-cancer effect. In this project, we aim to further boost the effectiveness of Delta-24-RGDOX by targeting factors that maintain the immunosuppressive characteristic of gliomas. Specifically, we identified the environmental sensor and transcription factor Aryl Hydrocarbon Receptor (AhR) as one of the immunosuppressive factors. We show that AhR is overexpressed in GBM surgical specimens compared to healthy brain tissue, and high AhR expression correlates with poorer survival in glioma patients. Immunofluorescence staining of glioma cells treated with Delta-24-RGDOX demonstrated that AhR translocates to the nucleus, and qPCR showed that translocation resulted in the enhanced transcription of AhR-responsive elements. Additionally, bulk RNA-seq reveals that in vivo glioma models treated with Delta-24-RGDOX exhibit activation of the AhR pathway network. This unexpected and paradoxical activation may be responsible for immune suppression mechanisms, which might hinder the effect of Delta-24-RGDOX. Based on these data, we combined two innovative strategies, the oncolytic virus Delta-24-RGDOX and AhR inhibitors. Survival analysis in immunocompetent models of gliomas treated with this combined therapy showed the greatest therapeutic benefit compared to monotherapy controls. These findings highlight the critical role of AhR activation triggered by Delta-24-RGDOX and position AhR as a potential therapeutic target for enhancing the efficacy of oncolytic adenovirus therapy in GBM.
IMMU-37. PRE-TREATMENT INNATE INFLAMMATION ASSOCIATES WITH SURVIVAL AFTER POLIO VIROTHERAPY AND CAN BE MODULATED TO SENSITIZE GLIOMAS TO IN SITU VACCINATION
Authors: Mazgaeen Lalita , Kornahrens William , Giang Jr Minh-Huy , Howell Georgia , Briley Aaron , Bowie Michelle , Nair Smita , Ashley David , Desjardins Annick , Gromeier Matthias , Brown Michael 
Published: November 2024

Abstract
Early-stage clinical trials in glioblastoma (GBM) have tested various virotherapy strategies, yet only a subset of patients appear to benefit. We previously demonstrated that a recombinant poliovirus (PVSRIPO) functions by inducing MDA5-dependent, type I interferon (IFN) dominant innate inflammation in myeloid cells to provoke durable and functional antitumor T cell responses in mice. Long-term survival after intratumoral PVSRIPO infusion was observed in a subset of patients with recurrent GBM (rGBM) in two clinical trials. Survival after PVSRIPO was associated with higher pre-treatment intratumoral neutrophil density and MHC-class II gene expression, but also higher pre-treatment inflammatory cytokines in blood. Post-treatment induction of type I/III IFNs detected in blood one day after PVSRIPO infusion also associated with survival of patients with rGBM, suggesting that the proficiency of IFN responses to PVSRIPO may dictate therapy outcome. In human ex vivo glioma tissue assays, only a subset of gliomas mounted type I IFN responses to PVSRIPO and STING agonist treatment, in a manner linked with higher pre-treatment IL-1b levels, and lower CXCL10 induction after treatment. Thus, baseline innate inflammation either influences or reflects the capacity of glioma tumors to respond to virotherapy. Strikingly, in glioma bearing mice, peripheral vaccination against tumor irrelevant vaccines in alum adjuvant (i.e., against antigens not expressed by the tumor) induced bone marrow, spleen and intratumoral innate inflammation; rescued the antitumor efficacy of PVSRIPO in an otherwise refractory glioma model; and improved survival after intratumor STING agonist therapy. Notably, peripheral vaccination induced intratumoral neutrophil and CD4+ T cell inflammation, and increased MHC-class II expression on myeloid cells. These data imply a role for pre-treatment systemic innate immune training in the antitumor efficacy of virotherapy and indicate that modulating either systemic innate inflammation and/or the inflammatory status of bone marrow myeloid progenitors may sensitize gliomas to virotherapy.