bluuebunny/crossref_metadata_2025_split huggingface dataset:
SURG-01. CYSTIC BRAIN METASTASES MANAGED WITH RESERVOIR PLACEMENT AND STEREOTACTIC RADIOSURGERY
Authors: Park David , Unadkat Prashin , Goenka Anuj , Schulder Michael 
Published: November 2021

Abstract

BACKGROUND
Stereotactic radiosurgery (SRS) has become a mainstay of treatment for patients with metastatic brain tumors. However, metastatic tumors with a large cystic component often exceed the size limit for safe and effective SRS. In such cases, surgical resection may not be the preferred first method of treatment, due to tumor location, patient co-morbidities, and patient preference. In such cases volume reduction by cyst aspiration followed by SRS may be a preferred option.

OBJECTIVE
To present the treatment of patients with cystic metastases using reservoir placement followed by SRS.

METHODS
Seven patients were treated with this method. We performed reservoir insertion for the aspiration of cystic component in each patient and followed that with outpatient SRS.

RESULTS
Mean overall volume reduction from this treatment method was 80% (range 46.5-94.9). Mean volume reduction from the cyst aspiration alone was 60.7% (range 3.5-90.9), and after SRS a further 71.6% (range 34.6-94.4), accounting for some cyst reaccumulation between the time of surgery and SRS. The interval between those two procedures were 24 days on average (range 11-58 days). Repeat reservoir aspiration was done a total of 10 times in 5 patients.

CONCLUSION
Cyst aspiration with reservoir placement followed by SRS is a good option for patients with large cystic brain metastases. The reservoir allows for repeat aspiration if needed. Catheter placement at the center of the cyst, and SRS within 2-3 weeks of surgery, can maximize the likelihood of a successful outcome.
SURG-15. PITUITARY SPINDLE CELL ONCOCYTOMA: A CASE REPORT AND LITERATURE REVIEW
Authors: Taka Taha , Yang Chen Yi , Limbo Joshua , Chan Alvin , Davies Jordan , Kuan Edward , Turner Scott , Hsu Frank P K 
Published: November 2021

Abstract

BACKGROUND
Spindle cell oncocytoma (SCO) of the pituitary gland is an extremely rare non-functional WHO grade 1 tumor. SCO are often misdiagnosed as nonfunctional pituitary adenomas on pre-operative imaging. They are often hypervascular and locally adherent, which increases hemorrhage risk and limits surgical resection, leading to increased risk of recurrence. We report a case of SCO treated at our institution and provide a review of the current literature.

METHODS
A 75-year-old male with a history of hypertension, left thalamic stroke, Parkinson’s disease, and normal pressure hypertension presented to neurosurgery clinic with bitemporal hemianopsia, hyponatremia, and abnormal gait and mobility. Imaging showed an enhancing intra- and suprasellar, hyperdense tumor mass measuring 3.0 cm in diameter. We performed a systemic literature search in the PubMed database to identify previous reports of spindle cell oncocytoma. After exclusion of studies that did not meet criteria, 32 publications were selected for critical reading.

RESULTS
The patient underwent an endoscopic transsphenoidal resection of the tumor via a multi-disciplinary team. The tumor was fibrous and adherent to the intrasellar dura, with gross invasion of the diaphragm sella, necessitating partial resection of the diaphragm. The defect was repaired, and the patient made an uncomplicated recovery. Post-operatively, the patient experienced improved vision. Upon literature review, SCO present in older adults with an average age of 56.2 ± 14.7 with visual deficits (67.9%), headache (33.3%), hypopituitarism (24.7%), and nausea (11.1%). Full resection was achieved in 38.6% of cases leading to recurrence rate of 23.5% with an average time until recurrence of 32.5 months (range 1-120 months).

CONCLUSION
Careful surgical technique is needed due to SCO hypervascularity and strong adherence to minimize risk of injury to surrounding neurovascular structures. Long-term follow up is recommended due risk of recurrence.
TAMI-19. IMMUNOHISTOLOGICAL ANALYSIS OF ANGIOGENIC FACTORS OTHER THAN VEGF IN GLIOBLASTOMAS IN RELATION TO THE USE OF BEVACIZUMAB
Authors: Ezaki Taketo , Tamura Ryota , Tanaka Toshihide , Kuranari Yuki , Miyake Keisuke , Yamamoto Yohei , Takei Jun , Akasaki Yasuharu , Murayama Yuichi , Tamiya Takashi , Sasaki Hikaru 
Published: November 2021

Abstract
Although bevacizumab was shown to improve progression-free survival and performance status of the patients with high-grade gliomas, clinical trials consistently showed lack of benefit in terms of patients’ overall survival. The recurrent tumors are inevitably more aggressive and invasive as compared with the original tumors, and the in-situ observation in actual human specimens is essential to elucidate the mechanism of resistance. In Japan, bevacizumab was approved not only for recurrent but also for newly diagnosed cases. The safety as well as efficacy of resection following neoadjuvant bevacizumab has been reported, and a phase II study is currently ongoing (UMIN-000025579). In the present study, the expression of angiogenic factors other than VEGF (basic fibroblast growth factor (bFGF), placenral growth factor (PlGF), angiopoietin1/2 and ephrinA2) was investigated by immunohistochemistry to be compared among tumors with no previous bevacizumab treatment, those resected following bevacizumab, and those refractory to bevacizumab. Fifty-nine samples from 42 patients were included; 24 of newly diagnosed glioblastomas with no previous bevacizumab (naïve group), 16 resected following neoadjuvant bevacizumab (effective group), and 6 resected after recurrence or autopsied (refractory/autopsied group). 12 were paired samples (8 naïve and refractory, 4 effective and refractory). The expression of PlGF significantly increased in the effective group as compared with the naïve group (p=0.003). In the paired specimens, there was a trend towards increased expression of PlGF in the second specimens (refractory/autopsied group) as compared with the specimens of initial surgery (p=0.083). Angiopoietin1, angiopoietin2 and ephrinA2 were characteristically expressed in the microvessels less than 15μm. The increased expression of PlGF might be associated with the recurrence after bevacizumab.
TAMI-23. ANTIBODY COCKTAIL IMMUNOTHERAPY FOR GLIOBLASTOMA BY DUAL TARGETING OF IL-6 AND CD40
Authors: Yang Fan , Brem Steven , Fan Yi 
Published: November 2021

Abstract
Glioblastoma (GBM) is refractory to current T cell-based immunotherapies such as checkpoint blockade. GBM is characterized by extensive infiltration of immunosuppressive macrophages that contribute to the treatment resistance. Here we develop a dual-targeting strategy to synergistically activate tumor-associated macrophages (Mφs), which efficiently overcomes GBM resistance to therapeutic blockade of the PD1 and CTLA4 checkpoints. Consistent with a pro-tumor role of IL-6 in alternative Mφ polarization, we here show that targeting IL-6 by genetic ablation or pharmacological inhibition moderately improves T-cell infiltration into GBM and enhances mouse survival; however, IL-6 inhibition does not synergize PD-1 and CTLA-4 checkpoint blockade. Interestingly, anti-IL-6 therapy reduces CD40 expression in GBM-associated Mφs. We identify a Stat3/HIF-1α-mediated axis, through which IL-6 executes an anti-tumor role to induce CD40 expression in Mφs. Combination of IL-6 inhibition with CD40 stimulation reverses Mφ-mediated tumor immunosuppression, sensitizes tumors to checkpoint blockade, and extends animal survival in two syngeneic GBM models. Notably, this antibody cocktail-based combination immunotherapy with checkpoint blockade almost doubles animal survival in the genetically engineered mouse GBM model and induces complete tumor regression in the GL261 model. Thus, antibody cocktail-based immunotherapy that combines checkpoint blockade with dual-targeting of IL-6 and CD40 may offer exciting therapeutic opportunities for GBM.
TAMI-35. DETECTING SINGLE-CELL INTERACTIONS IN ORGANOTYPIC CULTURES OF GLIOBLASTOMA USING BARCODED RABIES VIRUS
Authors: Andersen Brian , Wheeler Michael , Li Zhaorong , Chiocca E Antonio , Reardon David , Quintana Francisco 
Published: November 2021

Abstract
Cell-cell interactions are thought to drive tumor-promoting signals in the microenvironment of glioblastoma, but standard approaches for single cell analysis do not directly identify cell interactions and the mechanisms that mediate them. We recently developed a novel method to analyze cell-cell interactions—rabies barcode interaction detection followed by sequencing (RABID-seq), which combines barcoded viral tracing and single-cell RNA sequencing (scRNAseq). RABID-seq was first implemented in transgenic mice to investigate the interactions of astrocytes with other cells in the CNS enabling the study of astrocyte connectome perturbations and candidate therapeutic targets in multiple sclerosis and its pre-clinical model, experimental autoimmune encephalomyelitis (EAE). Here, we report the first use of RABID-seq in human tissues in organotypic cultures established from three IDH-wildtype glioblastoma (GBM) patients. In organotypic GBM cultures, initial infection by pseudotyped barcoded rabies virus deficient for viral glycoprotein was achieved after previous culture transduction with a lentivirus containing the avian TVA receptor and rabies glycoprotein under the human EF1a promoter. We employed this system to initially infect approximately 1,000 malignant or non malignant cells in the tumor microenvironment. After five days, infected cells were isolated from cultures and processed for single cell analysis using SMART seq. We were able to capture at least 6,000 interacting cells per tumor specimen, from which barcodes were recovered and cDNA was sent for sequencing. Here we present connectomic data from our initial cohort of three glioblastoma patients as an introduction to RABID-seq, with a focus on astrocyte-tumor interactions. Candidate mechanisms of cellular interactions will undergo functional validation in murine models of glioblastoma.
TAMI-45. MICROGLIAL CYTOKINES INDUCE INVASIVENESS AND PROLIFERATION THROUGH PYK2 AND FAK ACTIVATION IN HUMAN GLIOBLASTOMA CELL
Authors: Nunez Rebeca , Valle Miguel Mayol-Del , Almodovar Luis , Kucheryavykh Lilia 
Published: November 2021

Abstract
Glioblastoma (GBM) is the most aggressive and highly invasive primary brain tumor in adults. Evidence suggests that microglia create a microenvironment favoring glioma invasion and proliferation. Indeed, previous reports indicate the involvement of focal adhesion kinase (FAK) signaling cascades in glioma cell proliferation. Besides, studies from our laboratory support a critical role of Pyk2, a relative of FAK, in glioma invasion by tumor-infiltrating microglia. However, the microglial-released factors modulating Pyk2 and FAK signaling pathways are unknown. In this study, 20 human GBM specimens were evaluated to identify the cytokine expression patterns in purified microglia and FAK and Pyk2 phosphorylation in glioma cell fraction by RT-PCR and western blot. A Pierson correlation test demonstrated a high correlation (0.8-1.0) of gene expression for PDGFα, PDGFβ, SDF-1α, IL-6, IL-8, and EGF in percoll-purified microglia, and pPyk2(Y579/580) and pFAK(Y925) levels in glioma cell fraction. The role of cytokines in cell invasion and proliferation by Pyk2/FAK activation was further investigated in primary cell lines from three patients. Thirty percent up-regulation of pPyk2 and pFAK was detected in glioma cells treated (2 hrs.) with microglia conditioned media (MCM) compared to control cells. siPyk2 or siFAK knockdown identified IL-6 (100 μM) and EGF (1 μM) as key factors of Pyk2- and FAK-dependent activation in all glioma cell lines. Similar results with siPyk2 or siFAK were observed for matrix degradation, invadopodia formation, cell viability, and mitosis. Indeed, Tocilizumab (IL-6R blocker, 100 ng/mL) and Gefitinib (EGFR blocker, 1 μM) reversed the effect of MCM on glioma cell proliferation and invasion in all cell lines evaluated. These findings support a pivotal role of Pyk2 and FAK in enhancing proliferation and invasion of glioma tumors through IL-6 and EGF-dependent pathways. The latter could be of clinical relevance for new therapeutic developments in GBM patients.
TAMI-54. SEXUAL DIMORPHISM IN IRON ACQUISITION IN GLIOBLASTOMA
Authors: Pandya Bhavyata , Webb Becky Slagle , Zacharia Brad , Lathia Justin , Rubin Joshua , Berens Michael , Barnholtz-Sloan Jill 
Published: November 2021

Abstract
Sexual dimorphism in incidence and the clinical outcomes of Glioblastoma (GBM) has been reported, however, our knowledge of contributing biological mechanisms is limited. Iron acquisition is key to robust tumor growth. Upregulation of Transferrin (TF, iron transport protein)/Transferrin receptor (TFR) is critical for found in multiple different cancers, specifically, we have identified H-ferritin (FTH1) as a contributor to iron transport and protection in cancer stem cells. To interrogate brain tumor iron uptake mechanisms,we performed binding studies on homogenized samples of human male and female GBM tissue samples using 125I labeled TF and FTH1. Tumors from males had a ̴ 3.8-fold increased binding of both proteins compared to tumors from females. We interrogated iron uptake in a syngeneic orthotopic mouse model (GL261 cells) using male and female mice. After the tumors were established, radioactive 125I labeled TF and FTH1 proteins were injected retro-orbitally in the mice. After 24 hours, tumors wereremoved, and analyzed for TF and FTH1 uptake. Male tumors showed an increased uptake, of ̴ 3.2-fold, as compared to female tumors. There was no significant difference in TF uptake between male and female tumors nor between tumor and matched non-tumor brain tissue. We next queried role of FTH1 in the context of sexual dimorphism in GBM in a FTH1+/- mouse strain developed in our laboratory. Survival was monitored in the mice which were injected with GL261 cells at 3 months. Male mice that had reduced expression of FTH1 had poorer survival as compared to the male wild type controls whereas wild type and FTH+/- females had no major differences in survival outcomes. In summary, this study demonstrates sexual dimorphism in iron acquisition in GBM and animal models further suggesting a pathophysiological role of iron metabolism in GBM development and its possible role in prognosis.
TAMI-59. RECIPROCAL IMPACT OF CANCER IMMUNITY AND TUMOR HYPOXIA DURING GLIOBLASTOMA PROGRESSION
Authors: Sattiraju Anirudh , Kang Sangjo , Marallano Valerie , Brusco Concetta , Chen Zhihong , Ramakrishnan Aarthi , Shen Li , Hambardzumyan Dolores , Friedel Roland , Zou Hongyan 
Published: November 2021

Abstract
Tumor hypoxia is linked to poor outcome for glioblastoma (GBM), a highly malignant brain cancer, but the underlying mechanisms and the environmental factors that initiate tumor hypoxia are poorly understood. We tracked tumor hypoxia in GBM in immunocompetent mice with a hypoxia sensitive fluorescent reporter combined with single cell transcriptomics. We found that hypoxic GBM cells are quiescent, immunosuppressive and display a mesenchymal transition, all of which are linked to malignant potency. We also captured in vivo hypoxia gene signature, which is more represented in recurrent GBM and predicts worse outcome. Interestingly, hypoxic GBM cells is a diverse population, consisted of four subclusters, and enriched for immune pathways. Concordantly, our reporter highlighted a distinct geographic pattern of immune cells in hypoxic regions, with phagocytic tumor-associated macrophages (TAMs) and CD8+ cytotoxic T cells (CTLs) congregated in hypoxic cores confined by hypoxic GBM cells in pseudo-palisading patterns. Mechanistically, this is a dynamic temporospatial process, requiring cytokine CCL8. Remarkably, the sequestered TAMs also experience hypoxia, and they are reprogrammed to express immunotolerant markers by factors released from hypoxic GBM cells. Contrary to the conventional viewpoint that hypoxia arises from rapid tumor expansion outstripping vascular supply, we discovered anticancer immunity as an important driving force of tumor hypoxia; attenuating immune responses by implanting GBM in host mice with immunodeficiency or IL1β deletion greatly decreased GBM hypoxia. Analyses of human patient GBM samples highlighted a connection of mesenchymal subtype, immune response, and tumor hypoxia, all contributing to poor survival. Altogether, our study revealed a reciprocal influence of anti-tumor immunity and tumor hypoxia, which has significant ramifications for prognosis and immunotherapy for GBM.
TAMI-75. LIPID METABOLISM AS A THERAPEUTIC VULNERABILITY IN BET INHIBITOR-RESISTANT MEDULLOBLASTOMA
Authors: Lupien Leslie , Boynton Adam , Kumbhani Rushil , Gionet Gabrielle , Goodale Amy , Root David , Bandopadhayay Pratiti 
Published: November 2021

Abstract
MYC-driven medulloblastomas are a particularly devastating group of pediatric brain tumors that exhibit resistance and continued progression despite standard of care treatments. Our preclinical work identified BET-bromodomain inhibitors as a potentially promising new class of drugs for children with medulloblastoma and other MYC-driven cancers, providing rationale to evaluate these agents in clinical trials. However, treatment with BET inhibitor (BETi) alone is unlikely to be sufficient for a cure, with most tumors evolving to acquire resistance to single-agent targeted therapies. We applied an integrative genomics approach to identify genes and pathways mediating BETi response in medulloblastoma. These studies revealed that MYC-driven medulloblastoma cells with acquired resistance to BETi reinstate transcription of essential genes suppressed by drug, and exhibit changes in cell state and new vulnerabilities not present in drug-sensitive cells. We now have a growing body of evidence showing that BET inhibition downregulates the expression of key lipid metabolism genes and metabolism-related signaling pathways, and that medulloblastoma cells with adaptive resistance to drug differentially express and exhibit preferential dependency on specific lipid metabolic genes and transcriptional regulators. Our studies explore the possibility of exploiting these novel metabolic vulnerabilities in order to overcome BETi resistance and provide a more efficacious upfront therapy.
TMOD-06. CREATION OF PATIENT-DERIVED LOWER GRADE GLIOMA ORGANOID MODELS FOR PERSONALIZED TREATMENT RESPONSE ASSESSMENT
Authors: Abdullah Kalil , Buehler Joseph , Bird Cylaina , Savani MIlan , Sternisha Alex , Levitt Michael , Hatanpaa Kimmo , Richardson Timothy , McBrayer Samuel 
Published: November 2021

Abstract
Creating in vitro models of lower grade glioma represents a major challenge in neuro-oncology research. There are few such models that are tractable and widely used, which has hindered understanding of the biology of these tumors. Recently, substantial progress has been made in generating patient-derived in vitro organoid models of high grade glioma, but modeling lower grade disease remains difficult. Based on our experience creating neurosphere cultures of lower grade astrocytomas from genetically engineered mice, we hypothesized that modifying patient-derived organoid generation protocols to incorporate physiological oxygen levels would allow establishment and propagation of lower grade glioma organoids. In this study, we show that this approach supports efficient organoid model generation from primary glioma specimens across all histological subtypes and tumor grades (WHO Grade I-IV, n = 20). These organoid models retain key characteristics of their respective parental tumors, including IDH mutations and other genetic alterations, metabolite profiles, intratumoral heterogeneity, cellular composition, and cytoarchitectural features. Importantly, lower grade glioma organoids can be cultured for months and reanimated after biobanking. Our high success rate ( &gt;90%) in establishing organoid models from primary lower grade glioma tissue samples further highlighted opportunities for treatment response assessments. To perform longitudinal measurements of therapy-induced changes in glioma organoid viability, we designed a novel, non-invasive imaging assay (termed rapid apex imaging) to determine real-time treatment response in low and high grade gliomas. We evaluated longitudinal responses of glioblastoma and IDH1 R132H-positive Grade II astrocytoma organoids to temozolomide and olaparib with and without radiation treatment. We quantified topological changes in organoid structure by building a bioinformatics tool to translate imaging data into a cellularity metric as a biomarker of organoid response. Our work unveils an effective new method to create in vitro, personalized models of lower grade glioma that supports elucidation of treatment sensitivity profiles.
TMOD-12. COMPARING TUMOR CELL INVASION AND MYELOID CELL COMPOSITION IN GENETICALLY IDENTICAL PRIMARY AND RELAPSING GLIOBLASTOMA
Authors: Kälin Roland , Zhao Dongxu , Zhang Huabin , Uyar Ramazan , Tonn Jörg-Christian , Glass Rainer 
Published: November 2021

Abstract
Glioblastoma (GBM) recurrence after treatment is almost inevitable, but addressing this issue with adequate preclinical models has remained challenging. Here, we introduce a GBM mouse model allowing non-invasive and scalable de-bulking of a tumor mass located deeply in the brain, which can be combined with conventional therapeutic approaches. Towards this aim we genetically engineered mouse GBM cells to stably express the herpes simplex virus thymidine kinase. Strong reduction of the GBM volume is achieved after pharmacologically inducing a tumor-specific cell death mechanism by the prodrug ganciclovir. This is followed by GBM re-growth over a predictable timeframe. Pharmacological de-bulking followed by tumor relapse was accomplished with an orthotopic mouse glioma model. Relapsing experimental tumors recapitulated pathological features often observed in recurrent human GBM, like increased invasiveness or altered immune cell composition. Orthotopic implantation of GBM cells originating from biopsies of one patient at initial or follow-up treatment reproduced these findings. Interestingly, relapsing GBM of both models contained a much higher ratio of monocyte-derived macrophages (MDMs) versus microglia than primary GBM. This was not altered when combining pharmacological de-bulking with invasive surgery. We interpret that factors released from viable primary GBM cells preferentially attract microglia whereas relapsing tumors preponderantly release chemoattractants for MDMs. All in all, this relapse model has the capacity to provide novel insights into clinically highly relevant aspects of GBM treatment.