tbuckley/cabot-search huggingface dataset:
TMIC-22. MYELOID CELLS INDUCE IMMUNOSUPPRESSION AND HYPORESPONSIVENESS OF CHIMERIC ANTIGEN RECEPTOR T CELLS IN THE NEURONAL MICROENVIRONMENT OF GLIOBLASTOMA
Authors: Junyi Zhang, Jasmin von Ehr, Thomas Look, Jasim Kada Benotmane, Nicolas Neidert, Jan Kueckelhaus, Tobias Weiss, Dieter Henrik Heiland, Yahaya Abubakar Yabo
Journal: Neuro-Oncology (2024)

Abstract Chimeric antigen receptor T (CART)-cell therapy has shown little success in glioblastoma and other solid tumors, unlike in hematologic malignancies. The immunosuppressive milieu and intratumoral heterogeneity are some obstacles limiting the effectiveness of CART-cell therapy in glioblastoma. Our goal in this study is to investigate how CART-cell transcriptional adaptations and cellular interactions in the glioblastoma microenvironment drive T-cell hyporesponsiveness. Using a human neocortical slice model, we performed physically interacting cell sequencing (PIC-seq) to investigate the transcriptional diversity of NKG2D CAR-T cells and control T-cells in the glioblastoma ecosystem. Through the integration of spatially resolved T-cell receptors sequencing and PIC-seq, we investigated the cellular and receptor-ligand interactions in CART-treated glioblastoma cells. Gene regulatory networks were reconstructed to identify key transcriptional regulators of CD8 CART-cell dysfunction. We used in-silico perturbation to understand transcriptional drivers that could potentially enhance the cytotoxic response of CAR-Ts. Primary patient-derived glioma cells were inoculated into human neocortical slices from surgical access tissue specimens. After 3 days of tumor growth, slices were treated with NKG2D CARTs or control T-cells. We observed that after 2 days of anti-tumor T-cell response in the CART group, tumor growth did not differ between conditions. After 7 days of treatment, PIC-seq was used to profile CARTs (tomato+) and tumor cells (GFP+) as well as physically connected cells (+/+). We identified a transcriptional shift towards T-cell exhaustion in CART cells compared to T-cells lacking the NKG2D construct. This transcriptional phenotype was driven by myeloid-CART and myeloid-tumor interaction. We identified that tumor-associated macrophages with enhanced phagocytic function in proximity to mesenchymal-like tumor cells located within hypoxic niches are the main drivers of T-cell dysfunction. Gene regulatory network analysis demonstrated that MAF and BACH2 are key transcriptional regulators of CART-cell function. Myeloid-tumor and myeloid-T-cell interactions promote an immunosuppressive microenvironment and hyporesponsive T-cells in glioblastoma. Our data has the potential to catalyze the re-engineering and optimization of CART-cell therapies with sustained cytotoxic effect against glioblastoma.
CSIG-25. MAPK/ERK SIGNALING IN GLIOMAS MODULATES INTERFERON RESPONSES, PROMOTES TUMOR-MICROGLIA CROSSTALK, AND CONFERS SUSCEPTIBILITY TO ANTI-PD-1 AND ANTI-CTLA-4 IMMUNOTHERAPY
Authors: Kwang-Soo Kim, Junyi Zhang, Crismita Dmello, Elena Grabis, Victor Arrieta, Karl Habashy, Junfei Zhao, Joseph Duffy, Andrew Gould, Li Chen, Irina Balyasnikova, Peter Canoll, Peter Sims, Raul Rabadan, Catalina Lee-Chang, Dieter Henrik Heiland, Adam Sonabend
Journal: Neuro-Oncology (2024)

Abstract While immune checkpoint blockade (ICB) is not effective in unselected glioblastoma (GBM) patients, we previously established that MAPK/ERK signaling is associated with overall survival following anti-PD-1 and anti-CTLA-4 treatment in recurrent GBM. However, the causal relationship between MAPK/ERK signaling and susceptibility to ICB, as well as the mechanisms underlying this association, remain to be determined. We conducted in vivo kinome-wide CRISPR/Cas9 screenings in murine gliomas to identify key regulators of susceptibility to anti-PD-1 and CD8+ T-cell response and performed survival studies to validate the most relevant hits. Additionally, paired scRNA-seq with p-ERK staining, spatial transcriptomics, and ex-vivo slice culture of BRAFV600E mutant GBM tumors treated with BRAFi/MEKi were used to determine the causal relationship between MAPK signaling, tumor cell immunogenicity, and modulation of microglia phenotype. Our CRISPR/Cas9 screening results identified the MAPK pathway, particularly the RAF-MEK-ERK pathway, as the most critical modulator of glioma susceptibility to anti-tumoral immunity across all kinases. Survival studies showed that mice bearing high p-ERK gliomas exhibited prolonged survival with anti-PD-1 treatment, which was not seen when ERK phosphorylation diminished. MAPK activation in murine gliomas led to durable anti-tumoral immunity upon implant re-challenge, with memory T cell infiltration in long-term survivors. Elevated p-ERK in glioma cells was associated with interferon responses and antigen presentation. Moreover, in BRAFV600E human GBM cells with ERK1/2 knockout and in slice cultures of human BRAFV600E GBM tissue analyzed by spatial transcriptomics, we observed modulation of interferon responses by the MAPK/ERK pathway. Notably, in slice cultures from BRAFV600E mutant GBM, BRAFi/MEKi treatment disrupted the interaction between tumor cells and tumor-associated macrophages/microglia. In conclusion, the MAPK/ERK pathway is a critical driver of GBM susceptibility to anti-tumoral immunity, modulating the interferon responses and antigen-presenting machinery in glioma cells, as well as tumor cell interaction with the microenvironment.
TMIC-28. TITLE: AN IMMUNE-RELATED, SEX-SPECIFIC T-CELL SIGNATURE IN GLIOBLASTOMA MICROENVIRONMENT WITH PROGNOSTIC IMPACT
Authors: Giulia Romagnoli, Martina Offi, Imerio Capone, Andrea Tavilla, Irene Canini, Caterina Lapenta, Mariachiara Buccarelli, Martina Giordano, Valentina Tirelli, Massimo Sanchez, Alessandra Fragale, Stefano Giannetti, Giovanni Maria Ceccarelli, Rina Di Bonaventura, Francesco Doglietto, Alessandro Olivi, Liverana Lauretti, Mauro Biffoni, Lucia Ricci-Vitiani, Roberto Pallini, Lucia Gabriele, Quintino Giorgio D’Alessandris
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Glioblastoma, IDH-wildtype (GBM), is the most prevalent and aggressive primary brain cancer with a poor prognosis. Immune checkpoint inhibitors (ICIs) have been explored in GBM with limited success, highlighting the need for a better understanding of the tumor microenvironment (TME). This study investigated whether the expression of specific immune checkpoints on tissue-resident memory T cells (Trm) predicts patient outcomes. METHODS In a single cohort observational study, tumor samples from 45 histologically confirmed GBM patients were processed to obtain single-cell suspensions. Multiparametric flow cytometry was used to analyze the correlation of Trm phenotypes with overall survival (OS) and progression-free survival (PFS). Univariate and multivariate analyses were conducted to assess the prognostic significance of Trm subsets. RESULTS Low frequency of exausted Trm expressing programmed cell death protein 1 (PD1) and T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) was associated with better clinical outcomes. Multivariate analysis identified low CD8+CD103+PD1+TIM3+ Trm and Karnofsky performance status (KPS) ≥70 as the most significant independent prognostic factors for longer OS (hazard ratios—HR [95%CI]: 0.14 [0.04–0.52] p &amp;lt; 0.001, 0.39 [0.16–0.96] p = 0.04, respectively). Additionally, younger patients (&amp;lt;63 years) and males had distinct immune profiles affecting prognosis. Notably, the proportion of exausted CD8+CD103+PD1+ Trms had a prognostic correlate only in male patients, consistent with findings by other groups on the existance of gender-specific immune TME in GBM. CONCLUSIONS Further exploration of Trm-based immune profiling has the potential to shed light on GBM resistance to ICIs and to help in personalizing treatment strategies.
CNSC-46. GLIOBLASTOMA INITIATION, MIGRATION, AND CELL TYPES ARE REGULATED BY CORE BHLH TRANSCRIPTION FACTORS ASCL1 AND OLIG2
Authors: Bianca Myers, Kathryn Brayer, Luis Paez-Beltran, Matthew Keith, Hideaki Suzuki, Jessie New, Rebekka Anderson, Yunee Lo, Conner Mertz, Rahul Kollipara, Mark Borromeo, Richard Lu, Robert Bachoo, Jane Johnson, Tou Yia Vue
Journal: Neuro-Oncology (2024)

Abstract Glioblastomas (GBMs) are highly aggressive, infiltrative, and heterogeneous brain tumors driven by complex genetic alterations. The neurodevelopmental transcription factors ASCL1 and OLIG2 are highly co-expressed in GBMs. However, their combinatorial roles in regulating the hierarchy and heterogeneity of GBM cells are unknown. Here, we show that induction of somatic mutations in neural progenitor cells lead to the dysregulation of ASCL1 and OLIG2, which then function redundantly and are required for brain tumor formation in a mouse model of GBM. Subsequently, the binding of ASCL1 and OLIG2 to each other’s loci and to downstream target genes then determine the cell types and degree of migration of tumor cells. Notably, single-cell RNA sequencing (scRNA-seq) reveals that a high level of ASCL1 is key in promoting neural stem cell (NSC)/astrocyte-like tumor cell types, which are highly proliferative, migratory, and are marked by upregulation of ribosomal protein, oxidative phosphorylation, cancer metastasis, and therapeutic resistance genes.
TMOD-11. ADVANCED MRI ANALYSIS TO ASSESS CHEMO-RADIATION RESPONSE IN PEDIATRIC EPENDYMOMA MODELS
Authors: Lucas Eggers, Jane Song, Jenna Steiner, Angela Pierce, Andrea Griesinger, Nicholas Foreman, Natalie Serkova
Journal: Neuro-Oncology (2024)

Abstract Pediatric Ependymoma (EPN) is an aggressive brain tumor for which the benefits of chemo-radiation (CR) therapy have yet to be established. Our team has previously reported behavior patterns of EPN, including high tumor cellularity, cytological anaplasia, high mitotic index, tumor necrosis, and the presence of inflammatory cells such as M2-type macrophages. Recently, we have established advanced MRI protocols and computational algorithms for cell- and vessel-size imaging. The goal of this study is to develop advanced MRI analysis for CR response biomarkers (including tumor size, cell- and vessel-size correlates, and texture analysis) in mice with patient-derived xenografts (PDX) of pediatric EPN. Female severely immune deficient (SCID) mice were used for intracranial orthotopical inoculation of disaggregated tumors from pediatric EPN patients. All multi-parametric MRI sequences (fast spin echo, FLAIR, diffusion weighted, quantitative T2- and r2*-maps) were acquired on a Bruker 9.4 Tesla MRI scanner prior to CR, followed by 2 days and 2 weeks after CR treatment. All radiation treatment was performed using an animal image-guided precision XRAD irradiator (2Gyx5days), using MRI and CT guided EPN localization with added 30 mg/kg 5-fluoracil. All MRI analysis was performed using Bruker ParaVision software and MATLAB based modeling. The sensitivity of T2w-MRI scans was 0.2 mm for the smallest tumor detected; the median tumor volume at baseline was 2.5 mm3. Untreated mice showed rapid progression of tumor growth from small to intermediate to large EPN. The increased tumor sizes in untreated EPN were characterized by low ADC, highly elevated blood vessel density and large tumor cell size. A significant decrease in vessel size density and an increase in inflammatory cells were seen as soon as 2 days after CR therapy. The late response (2 weeks post CR) is characterized by increased ADC values and decreased cell size, resulting in significantly decreased tumor volumes.
TMIC-61. DEVELOPMENT OF A NOVEL NOTCH-TARGETING ONCOLYTIC HSV FOR GBM TUMORS
Authors: Karina Vazquez-Arreguin, Yoshihiro Otani, Kimberly Rivera-Caraballo, Balveen Kaur
Journal: Neuro-Oncology (2024)

Abstract Glioblastoma (GBM) is the most aggressive brain malignancy, which despite continuing worldwide efforts to develop new therapies, remains a deadly disease with limited treatment options. The NOTCH signaling pathway is often hyperactive in GBM tumors, and its activity contributes to tumor progression and resistance to treatment. The role of NOTCH signaling in tumor growth and resistance is well studied, but the significance of this pathway for immunotherapy of GBM is not very well understood. We have recently shown that NOTCH activation following virotherapy contributes to tumor regrowth and induces recruitment of monocytic MDSC cells into the tumor, which limit optimal immune activation to kill tumor cells. For this study, we have discovered a NOTCH interfering intracellular ligand (NIIL) that blocks NOTCH activation from inside glioma cells. RNA sequencing shows the expression of NIIL downregulates NOTCH signaling in vitro. To evaluate the effect of NIIL on virotherapy, we generated an oncolytic herpes simplex virus (oHSV) that also encodes for NIIL. This virus showed a slower spread in vitro but improved therapeutic efficacy in vivo in multiple models of intracranial tumors. In immune competent mice there was a significant improvement in the survival of mice treated with the NIIL-encoding virus, with a fraction of mice showing a complete response after a single treatment. Single-cell RNA sequencing analysis of immune infiltrates is ongoing to understand how NIIL impacts tumor microenvironment and anti-tumor immune therapy.
TMIC-36. EVALUATING PHARMACOLOGICAL INHIBITION OF LSD1 IN MODELS OF DIFFUSE MIDLINE GLIOMA AND EFFECTS ON IMMUNE MICROENVIRONMENT SIGNALING
Authors: Deokhwa Nam, Faith Hernandez, Lea Stitzlein, Oren Becher, Joya Chandra
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Diffuse midline glioma (DMG) is the leading cause of death for pediatric brain tumor patients. DMG is remarkably immunologically senescent, even in comparison to other “immune-cold” tumors like adult glioblastoma. Lysine specific demethylase-1 (LSD1) is a histone demethylase exerting context-specific mechanisms of gene repression and activation and can be inhibited pharmacologically. We found LSD1 regulates the expression of inflammatory cytokines such as Interleukin 18 (IL18) and immune signaling receptors in DMG. Here, we investigated whether IL18 is transcriptionally regulated by LSD1 in vitro and in vivo using clinically relevant small molecule inhibitors. METHODS LSD1 binding to the IL-18 promoter was evaluated using chromatin immunoprecipitation. Transcript and protein expression using qRT-PCR and western blotting assessed the impact of LSD1 inhibition on IL18-related pathways and immune signaling pathways. LSD1 inhibitors (IMG-7289 or GSKLSD1) were evaluated patient-derived xenograft models. Results. We found elevated LSD1 binding on the IL18 promoter in DIPG VI cells. Subsequent qRT-PCR and western blot analyses demonstrated increased IL18 protein levels following treatment with GSKLSD1 or IMG-7289 in DIPG VI cells, alongside heightened IL18 mRNA expression compared to DMSO-treated cells. Either GSKLSD1 or IMG-7289 treatment in DIPG IV cells also led to significantly elevated IL18 binding protein mRNA levels. Orthotopic xenografts using DIPG IV bearing mice dosed with LSD1 inhibitors over the course of 35 days several weeks showed a decrease in IL-18R, and an increase in IL-18 BP transcript levels alongside a significant increase in Slamf7 transcript levels. Some evidence of tumor inhibition was seen in male but not female mice treated with GSKLSD1. CONCLUSIONS Our investigation revealed IL18 as a direct target of LSD1 specifically in DIPG VI, and gender specific effects of GSKLSD1 treatment in vivo. Future studies will prioritize validating and elucidating the underlying mechanisms the therapeutic potential of LSD1 inhibition in DMG.
BIOM-47. SINGLE NUCLEOTIDE POLYMORPHISM IN SMARCB1 MUTATION FOR SCHWANNOMATOSIS
Authors: Yuliya Lakhina, Melissa Campbell, Brett Henshey, Marybeth Yonk, Hurley Haney, Muhibullah Tora, Yuhong Du, Sergei Koshkin, Kecheng Lei, Nicholas Boulis
Journal: Neuro-Oncology (2024)

Abstract Schwannomatosis, a form of neurofibromatosis, involves critical roles for the SMARCB1 gene. Clinical diagnosis guidelines recommend considering pathogenic variants or suspecting schwannomatosis to exclude splicing-related intron mutations. However, some patients may initially present with non-significant mutations and lack clinical signs of schwannoma, leading to misdiagnosis, missed annual assessments, malignancy awareness, and genetic consultation opportunities during pregnancy. Here, we reported a patient with a sporadic synonymous mutation in the SMARCB1 gene (SNP c.1032 C&amp;gt;T (p.Gly344Gly(GGC&amp;gt;GGT)) in exon 8), not previously associated with schwannomatosis. This patient, a 55-year-old female with an 8-year history of schwannomatosis, presented to the neurosurgical department for recurrent tumor removal. Initially, the clinical impact of the SMARCB1 mutation was undetermined, and other genes tested were wild-type. Both schwannomas exhibited a mosaic loss of nuclear SMARCB1 protein, ranging from 10% to 60%. Protein assays confirmed low levels of SMARCB1 protein, with a significant loss in the distal thigh schwannoma. It highlights the tumorigenic potential of single nucleotide polymorphism in the SMARCB1 gene and aids clinicians in making more accurate diagnoses in patients with pathologically confirmed schwannoma. It underscores the importance of long-term follow-up, increased awareness of recurrence and malignancy, and timely surgical planning in such patients.
CSIG-32. MODULATION OF HALLMARKS OF GLIOBLASTOMA MULTIFORME BY BIOACTIVE PHYTOCHEMICALS: A PRECLINICAL MECHANISTIC EVALUATION
Authors: Adam Bobak, Michael Steves, Emily McMahon, Matea Spahiu, Austin Rahman, Nicolette Casarcia, Anupam Bishayee
Journal: Neuro-Oncology (2024)

Abstract Glioblastoma multiforme (GBM) is an aggressive malignancy with extensive neovascularization, an immunosuppressive tumor microenvironment, and high recurrence rates. Bioactive plant secondary metabolites (phytochemicals), many from fruits and vegetables, have been extensively studied for GBM prevention and treatment. The objective of this study is to determine the effects of phytochemicals on GBM hallmarks and associated molecular mechanisms of action through evaluation of in vitro and in vivo studies. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed to collect articles using PubMed, ScienceDirect and Scopus. While 1,344 articles were screened, 115 in vitro and 36 in vivo studies met our inclusion criteria. The Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) review of bias tool assessed in vivo study bias. In vitro, 49 alkaloids, 10 phenolics, 2 sulfur- compounds, and 5 terpenoids modulated GBM hallmarks of cell growth, invasion, cell cycle progression, neovascularization, and apoptosis. The PI3K/Akt/mTOR pathway was suppressed by 13 phytochemicals. Apoptosis was induced by 15 phytochemicals activating caspase-3, whereas 11 compounds inhibited Bcl-2. Cell cycle modulation occurred through decreased cyclin-dependent kinases and increased p53, p21, and p27. In vivo, 17 alkaloids, 5 phenolics, 2 sulfur-compounds, and 2 terpenoids had effects on GBM hallmarks. Invasion and neovascularization were inhibited through MMP, HIF-1α, and VEGF modulation. Six phytochemicals induced apoptosis in vivo through caspases and Bcl-2. Utilizing the SYRCLE review of bias tool, the average score quality of animal studies is 10% with many indicators of bias unclear. Various phytochemicals show promise to prevent and treat GBM due to their effects on numerous GBM hallmarks. Study limitations include the inclusion of literature reporting effects of single agents and lack of clinical studies. Future research is warranted to fill gaps in our analysis before recommending phytochemicals for prevention and treatment of GBM, a perilous malignancy.
TMIC-63. DUAL IMMUNE CHECKPOINT BLOCKADE IN A NOVEL EGFR-DRIVEN MURINE GLIOMA MODEL INCREASES PERIPHERAL T CELL PROLIFERATION BUT FAILS TO PROLONG SURVIVAL
Authors: Marissa Li, Marissa Pioso, Joshua Breunig, Katie Grausam, David Nathanson, Robert Prins
Journal: Neuro-Oncology (2024)

Abstract Patients with glioblastoma (GBM) survive only 15-18 months following standard-of-care surgical resection and radio-chemotherapy. Immune checkpoint blockade (ICB), effective in extracranial cancers, failed to improve survival in patients with recurrent GBM in a multi-center phase III clinical trial. As such, we are interested in the molecular mechanisms that drive ICB resistance. Oncogenic EGFR activation is observed in ~50% of GBMs and is associated with immunosuppression; however, whether EGFR signaling impairs T cell function in GBM resulting in limited ICB efficacy remains unclear. Therefore, we leveraged the novel MADR-mEGFRvIII glioma model, which expresses murine EGFRvIII under a tetracycline-off system, to investigate the relationship between EGFR activation and responsiveness to dual anti-PD-1 and anti-CTLA-4 (10mg/kg) in vivo. Mice were bled prior to enrollment and weekly thereafter, which confirmed anti-PD-1-PD-1 binding via competitive flow cytometric assay. Following two weeks on treatment, animals were euthanized for immunophenotypic analyses of tumors and tumor-draining lymph nodes. These analyses revealed a significantly increased prevalence of peripheral CD11b+ myeloid cells and enhanced peripheral T cell proliferation, indicated by Ki67 positivity, after treatment with dual ICB compared to isotype control. However, these shifts did not translate to effective ICB-mediated recruitment of peripheral T cells to the tumor microenvironment and no significant survival benefit was observed (p=0.68, n=15/treatment arm). Given our previous findings that EGFR ablation via doxycycline enhanced intratumoral T cell infiltration, we hypothesize the rational combination of EGFR-targeted therapy and ICB will have a synergistic effect; thus, future directions include a study combining the two treatment regimens consisting of a lead-in with doxycycline to increase intratumoral T cell trafficking, followed by treatment with dual ICB. This work will provide insight into the interplay between oncogenic signaling and immunosuppression, contributing to the development of novel combination therapies in treating this lethal disease.