bluuebunny/crossref_metadata_2025_split huggingface dataset:
IMMU-33. MULTI-ANTIGEN RECOGNITION CIRCUITS OVERCOME CHALLENGES OF SPECIFICITY, HETEROGENEITY, AND DURABILITY IN T-CELL THERAPY FOR GLIOBLASTOMA
Authors: Watchmaker Payal , Choe Joseph , Simic Milos , Gilbert Ryan , li Aileen , Krasnow Nira , Carrera Diego , Yu Wei , Downey Kira , Celli Anna , Cho Juhyun , Briones Jessica , Dannenfelser Ruth , Cardarelli Lia , Sidhu Sachdev , Roybal Kole , Lim Wendell , Okada Hideho 
Published: December 2020

Abstract
Treatment of solid cancers with chimeric antigen receptor (CAR) T-cells is challenging because of a lack of target antigens that are both tumor-specific and homogenously expressed. While epidermal growth factor receptor (EGFR)vIII represents a glioblastoma (GBM)-specific antigen, its expression is heterogeneous within the tumor resulting in tumor escape. In contrast, more homogenously expressed GBM-associated antigens (GAA), such as EphA2, are non-ideal because of expression in other normal organs, yielding potential cross-reactive toxicity. As a way to safely target GAAs in the tumor without attacking normal cells expressing the same GAAs outside of the brain, we adapted a novel synthetic Notch (synNotch) receptor system and established a “prime and kill” sequential two-receptor CAR circuit. A synNotch receptor recognizes a specific priming antigen; the heterogeneous GBM neoantigen EGFRvIII or a brain tissue-specific antigen to prime the local expression of a CAR that mediates cytotoxicity against a GAA (e.g. EphA2). In orthotopic GBM6 glioma model, a patient-derived xenograft (PDX) with heterogeneous expression of EGFRvIII, intravenous infusion of T-cells transduced with EGFRvIII synNotch→anti-IL-13Rα2/EphA2 tandem CAR circuit resulted in long-term (over 100 days) survival and eradication of the heterogeneous tumor in all of 12 mice in two independent experiments. In contrast, constitutive CARs targeting EGFRvIII or IL-13Rα2/EphA2 (as a tandem CAR) failed to exhibit long-term anti-tumor response. Moreover, T-cells transduced with synNotch-regulated CAR maintain a less differentiated state which is associated with higher durability compared with ones with constitutive CAR in vivo. T-cells transduced with a synNotch→CAR circuit primed by a brain-specific antigen, myelin oligodendrocyte glycoprotein (MOG), exhibited a precise and potent local control of intracranial PDX without evidence of priming in extracranial organs. These data support the utility of synNotch→CAR circuits in EGFRvIII-negative GBM cases. By integrating multiple imperfect but complementary antigens, we improve both the specificity and persistence of T-cells directed against GBM.
IMMU-38. PRECLINICAL VALIDATION AND MANUFACTURE OF IL-8 RECEPTOR-MODIFIED CD70 CAR T CELLS FOR CLINICAL TRIAL
Authors: Jin Linchun , Tao Haipeng , Na Meng , Karachi Aida , Mendez-Gomez Hector , Weidert Frances , Hou Alicia , Sayour Elias , Mitchell Duane , Huang Jianping 
Published: December 2020

Abstract

BACKGROUND
Chimeric antigen receptor (CAR) modified T cell therapy is a promising treatment strategy for cancer therapy. We developed IL-8 receptor-linked CD70CAR (8R-70CAR), aiming to enhance T-cell intratumoral trafficking and persistence, guided by IL-8-secreting tumors. The preclinical results show that 8R-70CAR T cells induce complete tumor regression and long-lasting antitumor immunity, which necessitate further clinical development of this technology.

OBJECTIVE
To assess the toxicity of 8R-70CAR T cells, evaluate in vitro tumor recognition and expansion of the 8R-70CAR T cells, and develop clinically compliant SOPs for the CAR T cell manufacture.

METHODS
The m8R-70CAR (mouse), h8R-70CAR (human), and control CAR were constructed. Toxicology: C57BL/6J mice were intravenously injected with or without 2x106 m8R-70CAR T cells after total body irradiation (5Gy). The body weight, clinical signs, hematology, serum chemistry, serum cytokines, gross pathology, and histopathology of 12 vital organs were evaluated. Tumor recognition: T cells derived from GBM patients were transduced with h8R-70CAR and then co-cultured with CD70+ glioblastoma. INF-g production was measured. Ex vivo expansion: The G-Rex system was utilized for CAR T cell production, and the expansion of h8R-70CAR T cells was assessed by cell count.

RESULTS
No CAR T cell-related toxicity was observed in mouse study. In addition to a robust antitumor reactivity, the h8R-70CAR T cells present an auto-stimulative property that elicits greater ex vivo expansion compared to other CAR T cells tested. An approximately 1200-fold expansion was achieved during the 2 weeks CAR T cell production without additional stimulation, which allows production of the CAR T cells on a clinical trial scale using &lt; 100mL of whole blood.

CONCLUSION
The 8R-70CAR T cells are effective, auto-stimulative, and safe. These properties are fundamental for successful clinical applications in cancer treatment. A phase I trial using the 8R-70CAR T cells in newly diagnosed GBM will be initiated soon.
IMMU-39. TIM-3 APTAMER IN COMBINATION WITH RADIOTHERAPY RESULTS IN ENHANCED SURVIVAL IN DIPG MODELS
Authors: Martinez-Velez Naiara , Garcia-Moure Marc , Puigdelloses Montserrat , Laspidea Virginia , Ausejo Iker , Ramos Luis Isaac , Becher Oren J , Pastor Fernando , M Alonso Marta 
Published: December 2020

Abstract
Pediatric diffuse midline gliomas-H3-K27M-mutant are aggressive brain tumours that arise during childhood. Despite new advances in genomic knowledge and the significant number of clinical trial testing new targeted therapies, patient outcome is still insufficient. Cancer immunotherapy is opening new therapeutic options representing a hope for this orphan disease. Aptamers are single-stranded nucleic acid ligands design to achieve a remarkable affinity and specificity to their targets, comparable to antibodies. TIM-3, is a potential immune checkpoint target, typically involved in T-cell exhaustion. Recent studies showed that TIM-3 is also expressed in tumour and glial cells and it plays an important role in brain tumour responses mediated by myeloid cells. In this work, we examined the anti-tumour effect of an aptamer against TIM-3 alone or in combination with radiotherapy. Of importance, we tested TIM-3 aptamer in a murine glioma and DIPG model, where we not observed any toxicity. TIM-3 administration increased overall survival but was unable to control the disease. Of importance, TIM-3 combination with radiotherapy improved the overall survival of treated mice when compared with single treatments leading to 50% of long-term survivors. TIM-3 aptamer administration increase T-infiltration in the tumour site compared to non-treated or library control. Mechanistic studies performed on day 16 showed an increase in CD8 effector cells, a decrease in T-regulators Foxp3+ cells and an increase in IFN-gamma expression suggesting the triggering of an antitumor-immune response. Rechallenge experiments demonstrated immune memory in the long-term responders that led to reject tumour re-implantation, confirming that TIM-3 aptamer treatment in combination with RT elicits specific antitumor immunity in mouse glioma models. These results suggest that immuno-therapies approaches in combination with radiotherapy would be worth exploring in the treatment of deadly DMG-H3K27-Mutant tumours.
IMMU-42. DUAL ACTIVATION OF THE cGAS-STING PATHWAY AND AIM2-INDUCED PYROPTOSIS BY TUMOR-TREATING FIELDS PRODUCES ANTI-TUMOR IMMUNITY IN GLIOBLASTOMA
Authors: Chen Dongjiang , Sebastian Mathew , Hutchinson Tarun , Ghiaseddin Ashley , Warren Sonisha , Allen Annie , Jin Dan , Le Son , Tran David 
Published: December 2020

Abstract

OBJECTIVES
Tumor Treating Fields (TTFields) was approved in combination with adjuvant temozolomide chemotherapy for newly diagnosed Glioblastoma (GBM) patients and resulted in a significant improvement in overall survival. TTFields are low-intensity alternating electric fields that are thought to disturb mitotic macromolecules’ assembly. In many patients, a transient stage of increased peritumoral edema is often observed early during TTFields treatment, suggesting that a major component of therapeutic efficacy by TTFields may be an immune mediated process. We hypothesize that TTFields activate the immune system by triggering pyroptosis and type I Interferon (IFN) response.

METHODS
A panel of GBM cell lines were treated with TTFields at the clinically approved frequency of 200 kHz using an in vitro TTFields system. Cells were analyzed for the production of micronuclei and activation of both pyroptosis and STING pathways using immunostaining, quantitative PCR, ELISA and cytometry. Pre-treated mouse GBM cells were injected into mouse brain to monitor survive and immunophenotyping. GBM patients’ blood was collected, and PBMC were isolated and analyzed by single cell RNAseq.

RESULTS
TTFields resulted in a significantly higher rate of micronuclei structures released into the cytoplasm, which were co-localized with two upstream dsDNA sensors AIM2 and cGAS. TTFields-activated micronuclei-dsDNA sensor complexes led to i) induction of pyroptotic cell death, as measured by LDH release assay, and through AIM2-recruited caspase1 activation and cleavage of pyroptosis-specific Gasdermin D; and ii) activation of STING pathway leading to the increase of type I IFNs and pro-inflammatory cytokines. In mouse model, double knocking down of STING/AIM2 eliminated the tumor suppression effects caused by TTFields. TTFields pretreated wild type cells successfully elevated dendritic cell level in mouse cervical lymph nodes which can be reversed by double knocking down.

CONCLUSIONS
These results provide compelling evidence that TTFields induces effective anti-tumor immunity in GBM cells and patients.
IMMU-44. PRE-DIAGNOSTIC EOSINOPHIL LEVEL AND GLIOBLASTOMA DEVELOPMENT IN PATIENTS WITH AND WITHOUT ATOPIC DISEASE
Authors: Bushara Omar , Guzner Alexander , Burdett Kirsten , Murday Patrick , Pollevick Matias , Scholtens Denise , Kumthekar Priya 
Published: December 2020

Abstract

BACKGROUND
Glioblastoma (GBM) is the most common primary malignant brain tumor and carries a very poor prognosis. Recent data report a negative association between the incidence of GBM and atopic disease. The underlying immunologic mechanisms of protection and the associated potential biomarkers are unclear. The aim of this retrospective study is to assess the relationship of eosinophil count to GBM risk by collecting eosinophil count in GBM patients with and without existing atopic disease.

METHODS
This is a retrospective study of 790 patients diagnosed with GBM from 2009–2019. Of those patients, 140 had laboratory values at least one year prior to diagnosis. Chart review was used to exclude patients with lymphoma, leukemia, other cancers, myelodysplastic syndromes, and unconfirmed drug, food, and adhesive reactions. 14 patients with chart-confirmed allergic rhinitis, asthma, or eczema and 47 controls were found. Wilcoxon rank sum test was used to compare the two groups.

RESULTS
The two groups did not differ in pre-diagnostic eosinophil counts (p=0.426). The two groups also did not differ in pre-diagnostic basophil, lymphocyte, neutrophil, or monocyte counts. Pre-diagnostic eosinophil to lymphocyte, monocyte to lymphocyte, and neutrophil to lymphocyte ratios also did not differ between the two groups. There were no other quantitative differences that would suggest a difference in immune cell profile.

CONCLUSIONS
In our study, the subset of GBM patients with atopic disease did not significantly differ in eosinophil count or other white blood cell subtypes when compared to GBM patients without atopic disease. Given that atopic disease is a known protective factor, and our atopic patients with GBM had normal eosinophil counts, we conclude that underlying immunologic factors such as eosinophilia may be protective from GBM as opposed to simply the presence of atopic disease. Prospective analysis to best understand eosinophil count as a surrogate for GBM risk is warranted.
IMMU-47. PROTEIN PHOSPHATASE 2A INHIBITION IN NK CELL THERAPY FOR TREATMENT OF MEDULLOBLASTOMA
Authors: Lu Rongze Olivia , Ho Winson , Chiou Brandon 
Published: December 2020

Abstract
Checkpoint immunotherapy (ICB) thus far has shown limited efficacy against brain tumors, such as medulloblastoma (MB). Its low mutational burden is thought to result in a paucity of neoantigen to trigger an effective T-cell response. Natural killer (NK) cells, can recognize tumor cells independently of neoantigens, making them appealing against MBs. Modulation of NK cells to enhance cytotoxicity against MBs could be a novel treatment strategy. Protein Phosphatase 2A (PP2A), a ubiquitous serine/threonine phosphatase, has been shown to inhibit IFNg and Granzyme B production by NK cells. We hypothesize that NK92, a transformed human NK cell line, has intrinsic activity against human MB cells and that inhibiting PP2A pharmacologically can enhance cytotoxicity of NK92 cells. We performed NK cytotoxicity assay and granulation assay against human MB cell line D425. We also used a small molecular inhibitor, LB100, to modulate PP2A activity in NK92. NK92 cells were co-cultured with D425, in increasing E:T (Effector:Target) ratio for 4 hours. D425 cells were pre-labeled with CellTrace Violet dye. The percentage of D425 (Violet+) cells in apoptosis (Cas3/7+) or necrosis (AAD+) were compared with different ET ratios to quantify NK mediated cell cytotoxicity. We also measured CD107a expression in NK92 to assess granulation with LB100 treatment. D425 cells were sensitive to NK92 killing. Percentage of D425 cells either apoptotic or necrotic increased with increasing ET ratio, suggesting that there was NK92 mediated cytotoxicity. Percentage of killed D425 cells ranged from 18% at baseline (without NK92) to 80% at ET ratio of 20. Inhibition of PP2A using LB100, enhanced NK92 degranulation. CD107a+ NK92 cells increased from 19% to 28% with 8uM of LB100. NK92 cells are cytotoxic against MB cells in vitro and inhibition of PP2A in NK cells can enhance their activity against MB cells.
IMMU-49. PREDICTING PATIENT-SPECIFIC ANTIGENS FOR MEDULLOBLASTOMA IMMUNOTHERAPY
Authors: Dyson Kyle , Yang Changlin , Trivedi Vrunda , Wildes Tyler , Grippin Adam , Mitchell Duane 
Published: December 2020

Abstract

BACKGROUND
Identification of tumor rejection antigens remains a major barrier to the development of effective immunotherapeutics and their application to pediatric brain tumors. To identify candidate antigen targets for medulloblastoma adoptive cellular therapy, we performed a comprehensive immunogenomic analysis of medulloblastoma transcription profiles and in silico antigen prediction across a broad array of antigen classes. We hypothesized that medulloblastomas are immunologically heterogeneous and express genes with limited normal tissue expression that may serve as targets for immunotherapy.

METHODS
Immunologic heterogeneity was assessed using several published algorithms and approaches implemented within the R programming language. Patient-specific HLA haplotypes were called via customized Optitype and Phlat algorithms. Patient-specific tumor associated antigens (TAA) were selected only if expressed &gt;1 transcript per million (TPM) in tumor and the standardized expression across a human tissue database was below 1 TPM. Patient-specific HLA and TAA sequences were extracted from RNA-seq data for prediction with eight MHC class I and four MHC class II affinity algorithms. Only expressed mutations and personalized TAAs were used for antigenic epitope predictions. All epitopes were screened against a human reference proteomic library to guarantee that epitopes were not shared by other expressed isoforms or genes. Public mass-spec data was also screened for protein-level antigen expression.

RESULTS
Although absolute immune cell content is predicted to be low, immune gene-signature analysis revealed subgroup-specific differences. Antigen prediction analysis revealed most patients express few candidate neoantigen targets passing all filtering criteria. Importantly, cancer testis antigens as well as previously unappreciated neurodevelopmental antigens were found expressed across all medulloblastoma subgroups and most patients. Protein level antigen expression was confirmed for some predicted TAAs.

CONCLUSION
Medulloblastomas are immunologically cold yet subgroups have distinct immune cell gene-signatures. Using a custom antigen prediction pipeline, we identified potential tumor rejection antigens with important implications for development of medulloblastoma cellular therapies.
IMMU-50. BBB CROSSING NANO-IMMUNOMEDICINE COMBINATION THERAPY TO TREAT BRAIN PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA
Authors: Sun Tao , Yang Jiyuan , Gamburg Maximilian , Ljubimov Vladimir , Grodzinski Zachary , Black Keith , Holler Eggehard , Kopeček Jindřich , Ljubimova Julia 
Published: December 2020

Abstract

INTRODUCTION
Lack of standard treatment of Primary Central Nervous System Lymphoma (PCNSL) was acknowledged in phase III intergroup study (HOVON 105/ALLG NHL 24). PCNSL incidence is increasing for unknown reasons, particularly among persons over 65 years. One of the major limitations of successful treatment of PCNSL is the blood-brain barrier (BBB), which prevents drug delivery into the brain.

METHODS
Polymer nanoconjugate based on biodegradable poly(N-(2-hydroxypropyl) methacrylamide) (PHPMA) was used for treatment of BALB/C mice with intracranially inoculated murine A20 lymphoma. PHPMA-based nanoconjugates have defined synthesis strategy for BBB transcytosis, tumor targeting, and cancer cell killing. Nano immunodrug PHPMA/AP-2/Fab’/c-Myc inhibitor/H6 conjugate contains multiple AP-2 peptides for efficient delivery across the BBB and Fab’ fragments of αCD20 mouse Ab for CD20 receptor crosslinking on PCNSL cells. c-Myc inhibitor bound via a disulfide bond is transferred to the cytoplasm followed by cleavage. The therapeutic efficacy and survival were evaluated together with spectral flow cytometry and RNA-seq bioinformatic analysis of tumor tissues.

RESULTS
Nanoconjugates were able to penetrate BBB and accumulate in brain parenchyma. The best survival results were obtained for the group where nanoconjugate with αCD20 Fab’ causing tumor cell apoptosis and c-Myc antisense inhibitor was combined with αPD-1 checkpoint inhibitor. Survival compared to PBS-treated controls was significant (P=0.0006 by ANOVA). Ex vivo analysis of A20 brain lymphoma tissue after treatment with nanoconjugates demonstrated reduction of Tregs, associated with downregulation of IL-10 and IL-1β in plasma. Spectral flow cytometry revealed activation of tumor infiltrating T lymphocytes and M1 macrophages in lead nanodrug treated groups. RNA-seq data correlated with flow cytometry results indicating the activation of genes linked to IFN-γ pathway important for anti-tumor response and M1 macrophage activation. Immunostaining confirmed a marked increase of M1-specific iNOS expression in the nanodrug-treated tumors. Support: NIH grants: R01 CA188743, R01 CA206220, R01 CA209921
IMMU-51. NEUROLOGIC IMMUNE-RELATED ADVERSE EVENTS MIMICS, RISK FACTORS, AND MECHANISMS: CLIPPERS AND ASEPTIC MENINGITIS
Authors: Yuen Carlen , Rezania Kourosh , Park Deric , Reder Anthony 
Published: December 2020

Abstract
Neurological immune-related adverse events (irAEs) are rare toxicities that occur following immune checkpoint blockade. It is imperative to distinguish between irAEs and their mimics for successful treatment. We present the first case of CLIPPERS-like lesions in a patient with thymic cancer, thymoma, and a family history of neuromyelitis optica, following treatment with pembrolizumab. The brainstem lesion was in the anatomic location of the respiratory and cardiac centers. We also present a second case of aseptic meningitis irAE in a patient with prior graft-versus-host-disease following a single dose of nivolumab. These cases add to the growing evidence of CNS complications from immune checkpoint inhibitors. Risk factors for irAEs are not well established, and we explore potential risk factors and a possible mechanism from dysfunctional regulatory T cells.
INNV-05. TUMOR TREATING FIELDS (TTFIELDS) TREATMENT PLANNING FOR A PATIENT WITH ASTROCYTOMA IN THE SPINAL CORD
Authors: De Los Santos Jennifer , Arvatz Smadar , Zeevi Oshrit , levi Shay , Bomzon Zeev , Marciano Tal 
Published: December 2020

Abstract

BACKGROUND
The use of Tumor Treating Fields (TTFields) following resection and chemoradiation has increased survival in patients with Glioblastoma. Randomized data provide strong rationale for planning TTFields transducer array placement to maximize TTFields dose at the tumor in a patient-specific manner. Here we present a case demonstrating the use of numerical simulations for patient-specific TTFields treatment planning for a spinal tumor.

METHODS
Treatment planning was performed for a 48 year old patient following T10-L1 laminectomy, gross total resection, and postoperative chemoradiation for an anaplastic astrocytoma of the spinal cord. An MRI at 3 weeks following chemoradiation showed tumor recurrence. Based on the post-chemoradiation MRI, a patient-specific model was created. The model was created by modifying a realistic computational phantom of a healthy female. To mimic the laminectomy, the lamina in T10-L1 was removed, and the region assigned electric conductivity similar to that of muscle. A virtual mass was introduced into the spinal cord. Virtual transducer arrays were placed on the model at multiple positions, and delivery of TTFields simulated. The dose delivered by different transducer array layouts was calculated, and the layouts that yielded maximal dose to the tumor and spine identified.

RESULTS
Transducer array layouts, in which the arrays were placed on the back of the patient with one array above the tumor and one array below the tumor, yielded the highest doses at the tumor site. Such layouts yielded TTFields doses of over 3.4mW/cm3 which is well above the threshold dose of 1.1 mW/cm3 reported previously [Ballo et al Red Jour 2019].

CONCLUSIONS
These data represent the first ever study on utilizing numerical simulations in order to plan treatment for a spinal tumor in a patient-specific manner. This is an important milestone in the developing a framework for TTFields dosimetry and treatment planning.