bluuebunny/crossref_metadata_2025_split huggingface dataset:
TMIC-50. SIGLEC-15 IS A NEW MYELOID CHECKPOINT IN GBM, WHOSE SUPPRESSION LEADS TO EXTREMELY DURABLE RESPONSES WITH ONCOLYTIC THERAPY
Authors: Kesarwani Ashwani , Costa Amanda De Andrade , Hu Tong , Rich Jeremy , Kim Albert , Shi Pei-Yong , Diamond Michael S , Chheda Milan 
Published: November 2023

Abstract
Zika virus (ZIKV) significantly increases survival in multiple syngeneic glioma mouse models; like other oncolytic therapies, it generates a potent, anti-tumor CD8+ T-cell response. Post-ZIKV, we observe a 32-fold increase in myeloid cells in the tumor microenvironment. Siglec-15 is a newly identified myeloid immune checkpoint in cancer, which suppresses T-cell activation; an antibody targeting Siglec-15 is currently in clinical trial for lung cancer. Using immunostaining, for the first time, we report Siglec-15 is expressed on myeloid cells in human GBM specimens. In syngeneic murine models, anti-Siglec-15 alone does not improve survival. However, in combination with ZIKV, anti-Siglec-15 significantly improves survival in the CT2A, SB28, and GL261 models. For example, in the CT2A model, the combination increased long-term survivors (at least 90 days) to 60%, compared to 20% with ZIKV alone and 0% with no treatment. To further confirm the role of Siglec-15, we used Siglec-15 knockout (KO) mice and observed 70% long-term survivor rate in Siglec-15 KO mice treated with ZIKV, compared to 40% in wild-type mice (B/6) with ZIKV. ZIKV treatment in Siglec-15 KO mice led to activation of CD8 T-cells and increased expression of cytotoxic molecules granzyme B and perforin, indicating enhanced anti-tumor activity. Additionally, we detected high levels IFN-gamma and TNF-alpha, further supporting the anti-tumor response. We further improved efficacy by targeting PD-1. This combination resulted in 90% long-term survivors. Moreover, in a model for recurrence, upon contralateral rechallenge with CT2A in long-term survivors, we observed long-term memory T-cell responses, with increased numbers of CD8+ T-cells displaying effector and resident memory cell phenotypes, compared to age-matched controls. We obtained similar results with immune-resistant SB28 model. This work suggests that oncolytic therapy combined with blocking myeloid checkpoint Siglec-15, using an agent already in humans, and blocking CD8+ T cell checkpoint with anti-PD1, is worthy of study in humans.
TMIC-51. THE RELEASE OF INFLAMMATORY CYTOKINES ARE REGULATED BY PYK2 SIGNALING IN GBM CELLS
Authors: Morales-Colón Emely , Kucheryavykh Lilia 
Published: November 2023

Abstract
Glioblastoma (GBM) is a highly aggressive brain cancer that is typically fatal within a year of diagnosis. Previous research has shown a positive relationship between the activation of a protein called proline-rich non-receptor tyrosine kinase (Pyk2) in GBM cells in addition to the expression of cytokines by tumor-infiltrating myeloid (TIM cells). Leading to a sustained increase in the expression levels of monocyte chemoattractant protein 1 (CCL2), granulocyte-macrophage colony-stimulating factor (GM-CSF), IL10, IL12, and vascular endothelial growth factor (VEGF), as well as an increase in the CD86+/CD206+ TIM population. We hypothesize that Pyk2 signaling in GBM cells is involved in the regulation of the release of inflammatory cytokines, which in turn suppresses the immune response in the tumor microenvironment. We used CRISPR/Cas9 knockout Pyk2 (Pyk2KO) and wild type (Pyk2WT) GL261 mouse glioma cells in this study. Analysis of the cytokines present in the cell culture medium conditioned by Pyk2KO and Pyk2WT cells identified a decrease in the release of CCL2 and CCL5 in the Pyk2KO cells compared to the Pyk2WT cells. RT-PCR analysis of myeloid cell population, isolated from Pyk2WT and Pyk2KO tumors in the GL261-C57Bl/6 GBM model, identified a significant down-regulation of key pro-tumorigenic factors such as CCL2, CCL12, CCL5, tumor necrosis factor (TNF), VEGF and epidermal growth factor (EGF) in the Pyk2KO tumors compared to the Pyk2WT tumors. Additionally, flow cytometry analysis revealed a reduction in myeloid-derived suppressor cells (MDSCs), an increase in lymphoid dendritic cells (DC), and up-regulation in TNF/IFNg expressing and antigen-specific CD8+ T cells in Pyk2KO tumors. Furthermore, a significant decrease in pro-tumorigenic Ly6C+/CD206+ and an up-regulation of inflammatory Ly6C+/CD86+ myeloid cells were found in the Pyk2KO tumors. These findings suggest that Pyk2KO tumors display an immunocompetent microenvironment with enhanced phagocytic and cytotoxic function compared to Pyk2WT tumors. NIH Grant 1SC1GM122691 and PRSTRT2022 supported this study
TMIC-56. DECIPHERING THE INTRICATE GLIOBLASTOMA TUMOR MICROENVIRONMENT AND EGFRVIII TRANSCRIPT DISTRIBUTION THROUGH SINGLE-CELL SPATIAL PROFILING
Authors: Gregory Simon , Jain Vaibhav , Hocke Emily , Abramson Karen , Thomas Elizabeth , Satterfield Diane , Walsh Kyle , Brown Michael , McLendon Roger , Ashley David 
Published: November 2023

Abstract

INTRODUCTION
Profiling the tumor microenvironment (TME) in glioblastoma (GBM) poses challenges due to its complex and heterogeneous nature. Analyzing diverse cell populations, deciphering dynamic cell-cell interactions, and overcoming spatial-temporal variations present significant challenges to characterizing the GBM TME. These challenges can, in part, be overcome using in situ sequencing (ISS) approaches that offer the advantage of directly analyzing gene expression within intact tissue, providing spatial and molecular context for understanding complex biological processes and tumor heterogeneity. Method/

RESULTS
Here, we report a ‘first in world’ application of 10xGenomics Xenium ISS platform to profiling RNA expression profiles within GBM tissue, including primary and recurrent tumors, to establish single cell-level profiling of the TME. Our panel of canonical and custom GBM genes allowed us to establish profiles of high-resolution cell neighborhoods, intratumoral cell-types and cell-states, and the distribution of infiltrating tumor cells throughout the tissue. Exploiting the chemistry that underlies the Xenium platform, we also developed a novel ISS isoform expression assay that semi-quantitatively profiles a mutated variant of the epidermal growth factor receptor (EGFR). Data show that EGFRvIII, which has been shown to promote tumor growth, invasion, and resistance to therapies, is preferentially expressed within tumor-subsets within the GBM. Our EGFRvIII assay not only has the potential to act as a high sensitivity method of tumor diagnosis but its distribution will allow for correlation of this tumorigenic marker with activated pathways across the tissue.

CONCLUSION
ISS is a valuable tool for profiling the complex TME in GBM, enabling analysis of intratumoral cell types, cell states, and EGFRvIII distribution. Our study demonstrates its pioneering application, offering insights into the molecular landscape and potential for novel diagnostic signatures and improved treatment strategies for this aggressive cancer.
TMIC-59. IL-2 SECRETING ENGINEERED MYELOID CELLS POTENTIATE CYTOTOXIC EFFECTOR CELL ACTIVATION TO DELAY MALIGNANT PROGRESSION IN A PRECLINICAL MODEL OF GLIOMA
Authors: Canella Alessandro , Nazzaro Matthew , Haffey Abigail , Schmitt Claire , Behbehani Gregory , Rajappa Prajwal 
Published: November 2023

Abstract

INTRODUCTION
Gliomas are the most prevalent brain tumor in the adolescent and young adult population (AYA) and one of the leading causes of cancer-related death. In fact, two-thirds of glioma AYA patients are affected by low-grade gliomas (LGGs). Moreover, there are no therapies to prevent glioma LGG malignant progression. Malignant progression is associated with a significant reduction of tumor infiltrating cytotoxic effector immune cells, primarily due to the immunosuppressive tumor microenvironment (TME) mediated by regulatory T lymphocytes, tumor associated macrophages (TAMs), and myeloid-derived suppressor cells (MDSCs). To that end, immunotherapies have had limited efficacy in improving outcomes for primary and secondary HGGs.

HYPOTHESIS
We hypothesize that engineered myeloid cells that release IL-2 will enhance the trafficking of activated effector T cells and potentiate a pro-inflammatory cascade in the low-grade glioma TME, delaying malignant progression.

METHODS
Immunocompetent RCAS n/tv-a LGG bearing animals were retro-orbitally treated at day 21 with a single dose of bone-marrow derived myeloid cells, engineered for the release of Interlekin-2 (GEMys-IL2). The inflammatory status of the TME along with the composition and functional status of tumor infiltrating immune cells were investigated in vivo by cytokine array, mass cytometry, and bulk RNA sequencing.

RESULTS
Our complementary dataset demonstrated that GEMys-IL2 infiltrated the glioma microenvironment and triggered a pro-inflammatory cascade involving the upregulation and release of IL2, IFNy, CXCL9, Tim1, CD26 and other pro-inflammatory cytokines associated with the activation and recruitment of innate and adaptive immune cells within the TME. In addition, we observed a downregulation of immunosuppressive signaling pathways such as IL10, PPAR, LXR/RXR, CTLA4 and PD-1. Also, a single dose of GEMys-IL2 systemically injected in RCAS/t-va immunocompetent LGG bearing mice potentiated pro-inflammatory remodeling of the TME and significantly improved overall survival.

CONCLUSIONS
These preclinical studies highlight a novel approach in developing next-generation innate immunotherapies.
TMIC-60. CROSS-SPECIES ANALYSIS OF HUMAN AND NEW MOUSE MODELS OF GBM SUBTYPES IDENTIFIES VISTA AS A PROMISING IMMUNOTHERAPY TARGET
Authors: Madonado Jose , Wang Caiyi , Leu Jia-Shiun , Wong Thomas , Abdelfattah Nourhan , Gallup Thomas , Paik Jihye , Squatrito Massimo , Yun Kyuson 
Published: November 2023

Abstract
Immunotherapy is a promising treatment modality for GBM; however, clinical trials thus far have failed to provide significant clinical benefit to most patients. GBM is one of the “immune cold” tumors characterized by poor infiltration of T cells and the abundance of immune-suppressive myeloid cells that block T cell infiltration and/or activation. A major bottleneck to developing more effective immunotherapies is the paucity of faithful preclinical models to discover and validate new treatments. Here, we report multi-dimensional analyses of six different transplantable mouse glioma models in the C57BL6/J background that represent the three human GBM molecular subtypes. We performed whole exome sequencing, STR fingerprinting, immune phenotyping, and single-cell RNA-sequencing of each model and confirmed that the new models exhibit highly heterogeneous and immune suppressive TME, similar to human GBM. In addition, we performed cross-species comparisons of glioma and immune cell subtypes between human and mouse GBMs at the single-cell level and demonstrate strong concordances in molecular phenotypes and cellular heterogeneity. These result in qualitative and quantitative differences in the cell: cell communication among different stromal cells and glioma cells in each model, and we propose that these interactions shape the local niche and immune suppressive neighborhoods. Notably, in both human tissues and mouse models, PD1/PDL1 expression is low or sporadic, and, unlike the GL261 model, the new mouse models are resistant to anti-PD1 and CTLA4 treatment in vivo. Finally, we discovered that VISTA is a widely expressed immune checkpoint in both human and mouse GBM and demonstrate the efficacy of anti-VISTA and anti-PD1 combination therapy in the most immune-suppressive mouse model. In summary, we demonstrate the utility of these immune-competent mouse models and nominate anti-VISTA+PD1 treatment as a promising novel combination therapy for GBM.
TMIC-61. INVESTIGATING REPROGRAMING OF THE GBM’S TUMOR MICROENVIRONMENT AS A RESULT OF CO-TRANSFER OF HEMATOPOIETIC STEM CELLS (HSCS) WITH ADOPTIVE CELLULAR THERAPY
Authors: Reid Alexandra , Jin Dan , Dean Bayli DiVita , Font Laura Falceto , Francis Connor , Figg John , Flores Catherine 
Published: November 2023

Abstract
Glioblastoma (GBM) is an incredibly aggressive and prevalent primary CNS tumor with dismal survival outcomes. GBM’s intra-tumor heterogeneity and the powerful regulatory mechanisms within the tumor microenvironment (TME) that hamper immune activation have proved to be formidable challenges to the development of effective therapies. Fortunately, immunotherapy has emerged as a potentially powerful approach to achieve of immune activation within the TME through adoptive immunotherapy and checkpoint inhibition Our previous work has demonstrated that the survival benefit of adoptive cellular therapy (ACT) is significantly enhanced by concomitant transfer of bone marrow derived hematopoietic stem cells (HSC) with tumor-reactive T cells in preclinical models. Using a novel organotypic brain slice culture (BSC) model study using glioma-bearing C57BL/6J mice, we interrogate tumor microenvironment and directly demonstrate that the presence of HSC-derived cells in the microenvironment increases T cell migration to tumor, and increased tumor cell death. In addition, we can investigate reprogramming of the TME as a result of treatment with this ACT+HSC platform. These studies are unique in that through this model system, we are capable of studying the cell-cell interactions occurring within the tumor microenvironment TME longitudinally while accounting for the complexity and the spatial orientation of the components within the TME that promote immunosuppression and tumor escape.
TMIC-62. COMPLEMENT FACTOR H IS A NOVEL LIGAND FOR THE INDUCIBLE T CELL CO-STIMULATOR AND PROMOTES SURVIVAL OF REGULATORY T CELLS IN THE GLIOMA MICROENVIRONMENT
Authors: Smolag Karolina , Olszowka Jakub , Rosberg Rebecca , Johansson Elinn , Marinko Elisabet , Leandersson Karin , O′Connell David , Governa Valeria , Tüysüz Emre Can , Belting Mattias , Myriam Martin , Pietras Alexander , Blom Anna 
Published: November 2023

Abstract
The survival rates of glioma patients have not shown significant improvement in recent years despite aggressive treatment and advancements in immunotherapy. This lack of response to treatment can be attributed in part to the immunosuppressive microenvironment commonly found in gliomas, where regulatory T cells (Tregs) play a critical role in immunologic tolerance. In this study, we aimed to investigate the influence of complement factor H (FH) on Tregs within the glioma microenvironment. Our findings revealed that FH acts as a novel ligand for the inducible T cell costimulator (ICOS). This interaction between FH and ICOS promotes the survival of Tregs. Furthermore, FH enhances the functional capabilities of Tregs that are crucial for modulating the tumor microenvironment. These include the secretion of transforming growth factor beta and interleukin 10, as well as the suppression of effector T cell proliferation. Immunostaining of human and mouse gliomas demonstrated that cancer cells directly produce FH. Additionally, database analysis revealed an association between upregulated FH expression, the presence of Tregs, and poor prognosis in glioma patients. We validated these findings in a glioma mouse model, where knockdown of FH expression showed a clear tendency to prolong survival. Given that the accumulation of Tregs is indicative of a poor prognosis and represents a promising target for therapy, it is crucial to consider FH expression when evaluating the effectiveness of immunotherapies against glioma.
TMIC-69. TARGETING TUMOR-ASSOCIATED MACROPHAGES IN THE IMMUNE-MICROENVIRONMENT OF MENINGIOMAS
Authors: Lotsch Catharina , Warta Rolf , Trong Philip Dao , Unterberg Andreas , Herold-Mende Christel 
Published: November 2023

Abstract
Meningiomas represent the most common primary brain malignancies in adults with a subset of tumors exhibiting aggressive clinical behavior. Immunotherapy might present a new treatment strategy but is highly dependent on the immunological composition of the tumor microenvironment. Our previous data have shown that tumor-associated macrophages (TAMs) make up the main immune cell population in meningiomas with a significant negative impact on patient outcome. In this study, we investigated whether TAMs from meningioma tissue could be reprogrammed to an immunologically active and tumoricidal phenotype. For this purpose, CD11b+ sorted macrophages derived from &gt; 40 patients were treated with small molecule inhibitors targeting the colony-stimulating factor-1 receptor (CSF-1R). In a first analysis, the direct treatment response of CD11b+ patient-derived macrophages was investigated by various techniques including flow cytometry and bulk RNA-sequencing of treated TAMs and further analysis of the macrophage-conditioned media after treatment. In addition, we studied the influence of CSF-1R-targeted macrophage treatment on the phenotype and functional activity of T cells to assess a potential indirect treatment response in the tumor microenvironment. Our data revealed that CSF-1R-targeted treatment of CD11b+ TAMs induced significant changes in the protein and gene expression of macrophage polarization markers towards a more immunologically active state and a significantly higher metabolic nitric oxide production as another sign of immunological activation. Subsequent analysis of indirect effects on T cells showed not only a significantly increased expression of the T cell activation marker CD69+, but also a significantly increased tumor cell killing by autologous T cells after macrophage-targeted treatment. Together these data suggest both a direct and indirect CSF-1R-targeted macrophage treatment response in the local tumor microenvironment and give first promising results on the efficacy of macrophage-targeted immunotherapy in human meningiomas.
TMIC-75. SPATIALLY-RESOLVED TRANSCRIPTOME ANALYSIS OF BRAIN METASTATIC BREAST CANCER REVEAL KEY MEDIATORS OF BRAIN-TROPIC METASTATIC POTENTIAL
Authors: Umeh-Garcia Maxine , Godfrey Bryanna , Perez Pablo Nunez , Varma Sushama , Ahmadian Saman , Toland Angus , Granucci Monica , Averbukh Inna , Tian Lu , West Robert , Angelo Michael , Plevritis Sylvia , Gephart Melanie Hayden 
Published: November 2023

Abstract

BACKGROUND
In women with metastatic breast cancer, 30% (HER2+) to 50% (triple negative) develop brain metastases. Breast-to-brain metastasis carries a poor median survival of only 10 months and is accompanied by severe neurologic decline. Halting the progression of breast cancer brain metastases requires modulation of the tumor microenvironment (TME), yet little is known about how the primary breast TME affects brain tropism, or how, once there, metastatic cancer cells interact with normal brain cells (e.g., neurons, astrocytes, microglia).

METHODS
We constructed a large (n = 253 cores), diverse, clinically-annotated tissue microarray (TMA) of breast cancer brain metastases with surrounding brain (n = 127), associated primary breast tumors (n = 67, with 30 matched), normal brain (n = 23), and staining control (n = 18) tissue samples, from patients (n = 140) treated at Stanford Hospital between 2008 – 2018. We then leveraged a combination of genome-wide transcriptome analysis and high resolution spatial imaging (using GeoMx Digital Spatial Profiling) to interrogate the distinct, spatially-driven gene signatures of tumor, immune, and normal brain cells within the breast cancer brain metastasis TME.

RESULTS
We revealed novel gene regulatory programs that are associated with metastatic potential from the primary breast to the brain. We also identified not only diverging features of the breast and brain TMEs, but equivalent features which may contribute to preferential honing and outgrowth of metastatic breast cells in the brain microniche. Additionally, we uncovered significant cellular crosstalk between tumor, immune, and brain cell populations, including putative cell-cell interactions and intercellular signaling pathways.

CONCLUSION
These results served as a starting point for identifying key tumor-immune-brain interactions responsible for priming immune and brain tolerance of malignant cells, allowing outgrowth and progression of breast cancer brain metastases. Further investigation focused on tumor-brain crosstalk, specifically tumor-microglia interactions, will provide promising targets for therapeutic advancements.
TMIC-76. GLIOBLASTOMA VESSEL CO-OPTION OCCURS AS A RESISTANCE MECHANISM TO CHEMORADIATION VIA INDUCTION OF A NOVEL CELL STATE
Authors: Pettiwala Aafrin M , Pichol-Thievend Cathy , Anezo Oceane , Bourmeau Guillaume , Montagne Remi , Lyne Anne-Marie , Guichet Pierre-Olivier Guichet , Deshors Pauline , Ballestin Alberto , Blanchard Benjamin , Ravi Vidhya M , Joseph Kevin , Heiland Dieter Henrik , Julien Boris , Leboucher Sophie , Besse Laetitia , Legoix Patricia , Furumaya Charita , Marcos Laura Kovandzic , Masliantsev Konstantin , Daubon Thomas , Schnell Oliver , Beck Jürgen , Servant Nicolas , Karayan-Tapon Lucie , Cavalli Florence , Seano Giorgio 
Published: November 2023

Abstract
Glioblastoma (GB) is one of the deadliest types of human cancer. Despite a very aggressive treatment regime-including resection, chemo-radiation, its recurrence rate is more than 90%. Recurrence is mostly caused by highly resistant and invasive cells that spread from tumor bulk and are not removed by resection. To develop an effective therapeutic approach, we need to better understand underlying molecular and cellular mechanism driving therapy resistance and invasion in GB. To dynamically track the changes post-therapy and chemoradiation-resistant cells, we employed multiple bulk and single cell transcriptomics, phosphoproteome, in vitro and in vivo real time imaging, organotypic cultures, functional analysis, digital pathology and spatial transcriptomics on patient material and preclinical models of GB. We demonstrated that the chemoradiation and brain vasculature induce a transition to invasive functional cell state, which we rename as VC-Resist. Better cell survival, G2M arrest, senescence/stemness pathway induction, makes this GB state much more resistant. Notably, these GB cells are highly vessel co-opting allowing homing to perivascular niche, which in turn increases their transition to this cell state. Molecularly, the transition to VC-Resist cell state takes place through FGF-FGFR1 signaling that leads to activation of DNA damage repair, YAP and Rho pathways. These findings demonstrate that the perivascular niche and GB cell plasticity jointly generates a vicious loop that leads to resistance and brain infiltration during GB recurrence.