bluuebunny/crossref_metadata_2025 huggingface dataset:
TAMI-08. THE CCL2-CCR2 ASTROCYTE-CANCER CELL AXIS IN TUMOR EXTRAVASATION AT THE BRAIN
Authors: Hajal Cynthia , Shin Yoojin , Li Leanne , Serrano Jean Carlos , Jacks Tyler , Kamm Roger
Published: November 2021

Although brain metastases are common in cancer patients, little is known about the mechanisms of extravasation across the blood-brain barrier (BBB), a key step in the metastatic cascade that regulates the entry of cancer cells into the brain parenchyma through its selective endothelial barrier. Progress in this area has been impeded by challenges in conducting high spatio-temporal resolution imaging in vivo and isolating factors and cellular interactions directly contributing to extravasation rather than cancer survival and proliferation in the brain tissue. To address these limitations, we engineered a three-dimensional in vitro BBB microvascular model with endothelial cells derived from induced pluripotent stem cells, brain pericytes, and astrocytes, into which we perfused cancer cells to recapitulate their circulation and extravasation at the BBB. With this platform, we revealed that astrocytes play a major role in promoting cancer cell transmigration via their secretion of C-C motif chemokine ligand 2 (CCL2). We found that this chemokine promoted the chemotaxis and chemokinesis of cancer cells via their C-C chemokine receptor type 2 (CCR2), with no significant changes in vascular permeability. These findings were validated in vivo, where CCR2-deficient cancer cells exhibited significantly reduced cancer cell arrest and transmigration in mouse brain capillaries. Our results attest to the translational value of our BBB-on-a-chip model and reveal that the CCL2-CCR2 astrocyte-cancer cell axis plays a fundamental role in extravasation and consequently metastasis to the brain.
TAMI-17. INDUCTION OF SYNTHETIC LETHALITY BY ACTIVATION OF MITOCHONDRIAL CLPP AND INHIBITION OF HDAC1/2 IN GLIOBLASTOMA
Authors: Nguyen Trang , Shang Enyuan , Schiffgens Salveena , Torrini Consuelo , Bianchetti Elena , Shu Chang , Akman Hasan Orhan , Prabhu Varun , Allen Joshua , Westhoff Mike-Andrew , Karpel-Massler Georg , Siegelin Markus D
Published: November 2021

Activation of the mitochondrial ClpP protease is an innovative therapeutic concept and the identification of synthetic lethal interactions may foster the development of novel therapies for glioblastoma (GBM). By integration of a transcriptome, metabolite and U-13C-glucose tracing analyses, we showed that activation of the mitochondrial ClpP protease through constitutively active ClpP (Y118A) or utilization of second-generation imipridone compounds (ONC206 and ONC212) in combination with genetic interference of HDAC1 and HDAC2 as well as with global (Panobinostat) and selective (Romidepsin) HDAC inhibitors caused synergistic reduction of viability in established, neuro-sphere and patient-derived xenograft (PDX) cultures of human GBM, which was mediated by interference with tricarboxylic acid cycle activity and GBM cell respiration. Notably, human astrocytes were significantly less susceptible to the combination treatment of HDAC-inhibitors and ClpP activators. The reduction of GBM viability occurred independent of TP53 status and was accompanied by activation of cell death with apoptotic features along with cleavage of caspases regulated chiefly by Bcl-xL and Mcl-1. Importantly, knockdown of the ClpP protease or ectopic expression of a ClpP D190A mutant almost completely rescued from the inhibition of oxidative energy metabolism as well as from the reduction of cellular viability by ClpP activators and the combination treatment, suggesting critical involvement of this protein. Finally, utilizing GBM PDX models, we demonstrated that the combination treatment of HDAC-inhibitors and imipridones reduced tumor growth and prolonged host survival more potently than single treatments or vehicle in vivo. Collectively, these observations suggest that the efficacy of HDAC inhibitors might be significantly enhanced through ClpP activators in model systems of human GBM.
TAMI-22. SEGMENTATION OF DISTINCT TUMOR HALLMARKS OF GLIOBLASTOMA ON DIGITAL HISTOPATHOLOGY USING A HIERARCHICAL DEEP LEARNING APPROACH
Authors: Sandino Alvaro , Verma Ruchika , Chen Yijiang , Becerra David , Romero Eduardo , Tiwari Pallavi
Published: November 2021

PURPOSE

Glioblastoma is a highly heterogeneous brain tumor. Primary treatment for glioblastoma involves maximally-safe surgical resection. After surgery, resected tissue slides are visually analyzed by neuro-pathologists to identify distinct histological hallmarks characterizing glioblastoma including high cellularity, necrosis, and vascular proliferation. In this work, we present a hierarchical deep learning-based strategy to automatically segment distinct Glioblastoma niches including necrosis, cellular tumor, and hyperplastic blood vessels, on digitized histopathology slides.

METHODS

We employed the IvyGap cohort for which Hematoxylin and eosin (H&E) slides (digitized at 20X magnification) from n=41 glioblastoma patients were available. Additionally, expert-driven segmentations of cellular tumor, necrosis, and hyperplastic blood vessels (along with other histological attributes) were made available. We randomly employed n=120 slides from 29 patients for training, n=38 slides from 6 cases for validation, and n=30 slides from 6 patients to feed our deep learning model based on Residual Network architecture (ResNet-50). ~2,000 patches of 224x224 pixels were sampled for every slide. Our hierarchical model included first segmenting necrosis from non-necrotic (i.e. cellular tumor) regions, and then from the regions segmented as non-necrotic, identifying hyperplastic blood-vessels from the rest of the cellular tumor.

RESULTS

Our model achieved a training accuracy of 94%, and a testing accuracy of 88% with an area under the curve (AUC) of 92% in distinguishing necrosis from non-necrotic (i.e. cellular tumor) regions. Similarly, we obtained a training accuracy of 78%, and a testing accuracy of 87% (with an AUC of 94%) in identifying hyperplastic blood vessels from the rest of the cellular tumor.

CONCLUSION

We developed a reliable hierarchical segmentation model for automatic segmentation of necrotic, cellular tumor, and hyperplastic blood vessels on digitized H&E-stained Glioblastoma tissue images. Future work will involve extension of our model for segmentation of pseudopalisading patterns and microvascular proliferation.
TAMI-27. METABOLIC MANIPULATION OF T CELLS TO TREAT BRAIN TUMORS
Authors: Tian Guimei , Jin Linchun , Doshi Devshri , Karachi Aida , Dajac Mariana , Pohl-Guimaraes Fernanda , Moore Ginger , Rahman Maryam , Flores Catherine , Sarkisian Matthew , Huang Jianping , Mitchell Duane , Deleyrolle Loic
Published: November 2021

INTRODUCTION

Glioblastoma are a challenge for neuro-oncologists and current therapies are minimally effective. Standard-of- care treatment is almost inevitably followed by disease recurrence. Adoptive T cell transfer has emerged as a viable therapeutic for brain malignancies. While promising, the efficacy of this approach is often limited by a complex immunosuppressive tumor microenvironment. These complexities mean that more sophisticated T cell products are required.

OBJECTIVES

The brain tumor 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. The overall goal of this project is to test new treatments to reverse immune dysfunction in cancer through the regulation of T cell metabolic signaling. We propose that modulating glucose pathway in T cells can potentiate their anti-tumor activity once adoptively transferred.

METHODS

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

RESULTS

We demonstrated the existence of a competition for glucose between T cells and tumor cells, with tumor cells imposing glucose restriction mediating T cell hyporesponsiveness. Overexpression of glucose transporters such as Glut1 and Glut3 increased T cell glucose utilization and provide survival/growth advantage and enhanced T cell activation in glucose-restricted conditions. We also established that glucose transporter overexpression improves intratumoral infiltration of adoptively transferred T cells.

CONCLUSION

This project 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.
TAMI-36. TAMEP ARE BRAIN TUMOR PARENCHYMAL CELLS CONTROLLING NEOPLASTIC ANGIOGENESIS AND PROGRESSION
Authors: Kälin Roland , Cai Linzhi , Li Yuping , Hellmann Ines , Glass Rainer
Published: November 2021

Aggressive brain tumors like glioblastoma depend on support by their local environment and subsets of tumor-parenchymal cells may promote specific phases of disease-progression. We investigated the glioblastoma microenvironment with transgenic lineage-tracing models, intravital imaging, single-cell transcriptomics, immunofluorescence analysis as well as histopathology and characterized a previously unacknowledged population of tumor-associated cells with a myeloid-like expression profile (TAMEP) that transiently appeared during glioblastoma growth. TAMEP of mice and humans were identified with specific markers. Strikingly, TAMEP did not derive from microglia or peripheral monocytes but were generated by a fraction of CNS-resident, SOX2-positive progenitors. Abrogation of this progenitor cell-population, by conditional Sox2-knockout, drastically reduced glioblastoma-vascularization and -size. TAMEP manipulation profoundly altered vessel function and strongly attenuated the blood-tumor barrier. Hence, our data indicate TAMEP and their progenitors as new targets for glioblastoma therapy.
TAMI-58. TARGETING GLIOBLASTOMA BY ACTIVATING VIRAL SPECIFIC TISSUE-RESIDENT MEMORY T CELLS
Authors: Ning Jianfang , Gavil Noah , Wu Shaoping , Ma Jun , Li Ming , Grigore Florina , Dhawan Sanjay , Masopust David , Chen Clark , Rosato Pamela
Published: November 2021

Immunotherapy with the success of checkpoint blockade brings hope for cancer treatment with enduring or complete responses in various types of advanced malignancies, however, it has not benefited a number of so called “cold tumors”, such as glioblastoma multiforme (GBM), the most common and aggressive adult brain cancer. GBM is invariably lethal with a median survival of less than 15 months and characterized by a highly immunosuppressive tumor microenvironment, which desires new means of GBM immune-reactivation. Tissue-resident memory CD8+ T (TRM) cells are non-recirculating memory T cell subpopulation that resides permanently in peripheral tissues. TRM cells provide long-lived protective immunity against not only local pathogen infection but also tumor development through immediate effector function and recruitment of circulating immune cells upon antigen re-exposure. In this study, we found that memory T cells specific to some common human viruses that have infected almost everybody exist in clinical GBM specimens and can be activated by viral peptides, which are MHC I restricted CD8+ T cell epitopes derived from those viruses. In orthotopic GBM immunocompetent mouse models, we detected abundant virus specific TRM cells in the tumor microenvironment of GBMs intracranially established in mice that were previously exposed to the virus. Excitingly, intratumoral injection of viral peptides stimulated the reactivation of TRM cells, indicated by secretion of immuno-stimulatory cytokines, and demonstrated significant anti-tumor efficacy. This study provides proof of principle for TRM cell-based GBM therapy, which is a novel therapeutic paradigm with the translational potential for this deadly malignancy.
TAMI-61. EXAMINING THE ROLE OF HYPOXIA INDUCED GENES CXCR4 AND NXPH4 IN INVASION OF HYPOXIC GLIOBLASTOMA CELLS
Authors: Marallano Valerie , Sattiraju Anirudh , Zou Hongyan , Friedel Roland
Published: November 2021

Hypoxia (low oxygen) has been associated with adverse effects in tumor biology by exaggerating the capabilities of invasion, proliferation, and survival of tumor cells within the tumor microenvironment. We engineered glioblastoma (GBM) proneural cells with a novel hypoxia reporter, HRE-UnaG, to study areas of tumor hypoxia and the effects that these hypoxic cells have on tumorigenesis. Single cell RNA-seq analysis from a mouse intracranially injected with our HRE dUnaG GBM cells revealed a shift to a mesenchymal state upon hypoxia (detected by expression of UnaG). Two genes, CXCR4 and NXPH4, were identified as being specifically induced in the hypoxic population. Our studies focus on the hypothesis that these two hypoxia induced genes, CXCR4 and NXPH4, are upregulated in hypoxic GBM cells, which may allow tumor cells to become more aggressive and resistant to conventional forms of therapies. GBM cells will be transduced with lentiviral vectors for Dox inducible shRNA knockdown of CXCR4 or NXPH4 to test specific contribution of these genes to the phenotype of the hypoxic population, with particular focus on the change in invasion and overall tumor burden upon gene silencing.
TAMI-69. NF1 MUTATION DRIVES NEURONAL ACTIVITY-DEPENDENT OPTIC GLIOMA INITIATION
Authors: Pan Yuan , Hysinger Jared , Barron Tara , Schindler Nicki , Cobb Olivia , Guo Xiaofan , Yalçın Belgin , Anastasaki Corina , Mulinyawe Sara , Ponnuswami Anitha , Scheaffer Suzanne , Ma Yu , Chang Kun-Che , Xia Xin , Toonen Joseph , Lennon James , Gibson Erin , Huguenard John , Liau Linda , Goldberg Jeffrey , Monje Michelle , Gutmann David
Published: November 2021

Neurons have recently emerged as essential cellular constituents of the tumor microenvironment, where their activity increases the growth of a diverse number of solid tumors. While the role of neurons in tumor progression has been previously demonstrated, the importance of neuronal activity to tumor initiation is less clear, particularly in the setting of cancer predisposition syndromes. In the Neurofibromatosis-1 (NF1) cancer predisposition syndrome, in which tumors arise in close association with nerves, 15% of individuals develop low-grade neoplasms of the optic pathway (optic pathway gliomas [OPGs]), during early childhood, raising the intriguing possibility that postnatal light-induced optic nerve activity drives tumor initiation. Here, we employ an authenticated murine model of Nf1-OPG to demonstrate that stimulation of optic nerve activity increases optic glioma growth, while decreasing visual experience via light deprivation prevents tumor formation and maintenance. We show that Nf1-OPG initiation depends on visual experience during a developmental period susceptible to tumorigenesis. Germline Nf1 mutation in retinal neurons results in aberrantly high optic nerve neuroligin-3 (Nlgn3) shedding in response to retinal neuronal activity. Moreover, genetic Nlgn3 loss or pharmacological inhibition of Nlgn3 shedding blocks murine Nf1 optic gliomagenesis and progression. Collectively, these studies establish an obligate role for neuronal activity in the development of certain brain tumors, elucidate a therapeutic strategy to reduce OPG incidence or mitigate tumor progression, and underscore the role of Nf1 mutation-mediated dysregulation of neuronal signaling pathways in the NF1 cancer predisposition syndrome.
TAMI-71. EFFECTS OF THE TREATED MICROENVIRONMENT ON GLIOMA CELL PROPERTIES IN AN ORGANOTYPIC BRAIN SLICE MODEL
Authors: Pantazopoulou Vasiliki , Berg Tracy , Pietras Alexander
Published: November 2021

Glioblastoma is the most aggressive primary brain tumor. Despite treatment all patients invariably recur. Treatment resistance is attributed to the presence of glioma stem-like cells. Initially thought to be a distinct and static cell population, it is becoming increasingly clear that the glioma stem-like cell phenotype represents one of many cellular states and that glioma cells show plasticity between stem-like and non-stem like states. These plastic cell states are affected by the tumor microenvironment. In our lab we have shown that irradiated and hypoxic astrocytes increase the stem-like cell properties of glioma cells. In this study, we aim to evaluate how the treated microenvironment alters glioma cell properties and use ex vivo organotypic brain slices generated from tumor bearing and tumor naïve mice to assess all aspects of the microenvironment. We first characterized organotypic brain slices cultured in different oxygen tensions. We saw that tumor-bearing slices survive for at least 14 days in culture at 21%, 5% or 1% oxygen tension (O2). Tumor cells were more viable in all culture conditions and timepoints compared to non-tumor cells. Moreover, we found that astrocytes seem to be attracted to tumor areas in both 5% and 1% O2 cultures. We then used the organotypic glioma slice culture system to address how preconditioning the microenvironment using radiation or temozolomide affects the properties of glioma cells that are seeded in these pretreated, tumor naïve slices. We saw that fluorescently labelled glioma cells seeded in treated slices can be isolated after two days of culture in the slices and can be used for downstream analyses, such as temozolomide or radiation treatment and colony formation. This study will elucidate the effect of the treated microenvironment on glioma cell properties by using the medium throughput method of organotypic slice cultures.
TAMI-76. INTEGRATED MULTI-OMICS REVEAL INTRATUMOUR HETEROGENEITY AND NOVEL THERAPEUTIC TARGETS IN PAEDIATRIC EPENDYMOMA
Authors: Pandele Alina , Woodward Alison , Lankford Sophie , Macarthur Donald , Kamaly-Asl Ian , Barrett David , Grundy Richard , Kim Dong-Hyun , Rahman Ruman
Published: November 2021

Ependymoma (EPN) is the second most common malignant paediatric brain tumour with a five-year survival rate of only 25% following relapse. While molecular heterogeneity between EPN tumours is well understood, little is known concerning spatially-distinct intratumour heterogeneity within patients. In this context, we present a multi-omics integration of expression data at transcriptomic and metabolomic levels revealing intratumour heterogeneity and novel therapeutic targets. Surgically resected ependymoma tissue from two epigenetic subgroups, posterior fossa-A (PF-A) and supratentorial RELA, were first homogenised and polar metabolites, lipids and RNA simultaneously extracted from the same cellular population. Using liquid chromatography-mass spectrometry (LC-MS) and RNAseq 115 metabolites and 1580 upregulated genes were identified between the two subgroups, therefore validating previously reported genetic clustering of these two subtypes. Sampling of anatomically distinct regions was performed between eight PF-A EPN patients and multi-omic data was compared across 28 intratumour regions, with at least 3 different regions per patient. Integration of genes and metabolites revealed 124 dysregulated metabolic pathways, encompassing 156 genes and 49 metabolites. A large number of interactions occur in the gluconeogenesis and glycine pathways in 6 out of 8 patients, putatively representing therapeutically relevant ubiquitous metabolic pathways critical for EPN survival. Each anatomical region also presented at least one unique gene-metabolite interaction demonstrating heterogeneity within and across PF-A EPN tumours. A subset of the eight most prevalent genes across patients (GAD1, NT5C, FBP1, FMO3, HK3, TALDO1, NT5E, ALDH3A1) were selected for in vitro metabolic assays using 10 repurposed cytotoxic agents against PF-A EPN cell lines derived from intratumour regions of the same patient. 5/8 genes map within the gluconeogenesis metabolic pathway, further highlighting its significance within PF-A EPN. This is the first instance where multi-omic data integration and intratumour heterogeneity has been investigated for paediatric EPN revealing novel potential targets in the context of gene-metabolite correlations.
TAMI-80. CELLULAR METABOLISM IN DIFFUSE INTRINSIC PONTINE GLIOMA
Authors: Ijare Omkar , Manalo Jeanne , Sharpe Martyn , Baskin David , Pichumani Kumar
Published: November 2021

Diffuse intrinsic pontine glioma (DIPG) is an aggressive form of brain tumor in children, comprising >10% of all pediatric brain tumors. The median survival after diagnosis is < 1 year. Since DIPG tumors infiltrate brainstem and pons, they are inoperable. Currently radiotherapy is the mainstay of treatment, and there is a great need for novel therapies for the treatment of DIPG. Cellular metabolism plays a key role in carcinogenesis, unravelling active metabolic pathways in DIPG would help in developing targeted therapies. Glucose and glutamine are the two major nutrients necessary for the growth and proliferation of cancer cells. In this study, we have investigated the glucose and glutamine metabolism in SF8628 DIPG cells using 1H/13C NMR and GC-MS based metabolic flux analysis. SF8628 cells were grown in DMEM containing 11.0 mM glucose, supplemented with 10% FBS, and 2.0 mM glutamine at 37 °C under humidified air and 5% CO2. When cells reached confluency (replicates = 4), treated with 11.0 mM [U-13C]glucose or 4.0 mM glutamine in DMEM (supplemented with 10% FBS). After 24 h, cells were harvested for NMR/GC-MS analysis. The 13C-isotopomer analysis revealed that SF8628 cells produced 25.26 ± 10.63% acetyl-CoA from [U-13C]glucose which is ~3.7 times higher than that produced from GBM cells (6.83 ± 0.76%; our previous work), suggesting that DIPGs are metabolically very active. [U-13C]glutamine metabolism showed that DIPG cells also have an active TCA cycle metabolism (citrate M+4; 40.07 ± 1.06%) and moderately active reductive carboxylation pathway (citrate M+5; 10.59 ± 1.13%). Inhibition of both glycolytic and glutaminolysis pathways will be valuable in developing treatment strategies for DIPGs and these studies are in progress.
TMOD-02. GENERATION OF A NOVEL MOUSE MODEL FOR BRAIN TUMORS OF THE DNA METHYLATION CLASS “GBM MYCN”
Authors: Schoof Melanie , Göbel Carolin , Holdhof Dörthe , Al-Kershi Sina , Schüller Ulrich
Published: November 2021

DNA methylation based classification of brain tumors has revealed a high heterogeneity between tumors and led to the description of multiple distinct subclasses. The increasing subdivision of tumors can help to understand molecular mechanisms of tumor development and to improve therapy if appropriate model systems for preclinical research are available. Multiple recent publications have described a subgroup of pediatric glioblastoma which is clearly separable from other pediatric and adult glioblastoma in its DNA methylation profile (GBM MYCN). Many cases in this group are driven by MYCN amplifications and harbor TP53 mutations. These tumors almost exclusively occur in children and were further described as highly aggressive with a median overall survival of only 14 months. In order to further investigate the biology and treatment options of these tumors, we generated hGFAP-cre::TP53 Fl/Fl ::lsl-MYCN mice. These mice carry a loss of TP53 and show aberrant MYCN expression in neural precursors of the central nervous system. The animals develop large forebrain tumors within the first 80 days of life with 100 % penetrance. These tumors resemble human GBM MYCN tumors histologically and are sensitive to AURKA and ATR inhibitors in vitro. We believe that further characterization of the model and in vivo treatment studies will pave the way to improve treatment of patients with these highly aggressive tumors.
TMOD-04. T-TYPE CALCIUM CHANNELS DRIVE GLIOBLASTOMA INITIATION AND PROGRESSION
Authors: Dube Collin , Zhang Ying , Jr Myron Gibert , Mulcahy Elizabeth , Ottolini Matteo , Xu Esther , Sorot Aditya , Perez-Reyes Edward , Sonkusare Swapnil , Abounader Roger
Published: November 2021

Glioblastoma is the most common primary malignant brain tumor with a dismal median survival of 15 months. Calcium signaling regulates a plethora of cellular processes making it an ideal target for therapeutic intervention. Our group identified T-type calcium channels (TTCCs) as upregulated in GBM cells, stem cells and human tumors. Analysis of the Cancer Genome Atlas (TCGA) demonstrates for the first time that >20% of GBM patients exhibit mutation, amplification or mRNA upregulation of TTCCs. TCGA and Chinese Glioma Genome Atlas (CGGA) data analyses demonstrate that patients with alterations in TTCC trend toward worse survival compared to normal TTCC expression. Our group utilized an FDA repurposed TTCC blocker Mibefradil to demonstrate inhibition of TTCCs decreases cancer associated signaling, transcription, malignancy parameters and in vivo tumor growth. Mibefradil treatment sensitized Gliomas stem like cells (GSC) xenografts to temozolomide (TMZ) chemotherapy and radiotherapy. To elucidate the roles of the individual TTCCs in vivo we created RCAS/Tva-shTTCC mice for silencing of Cav3.1 and Cav3.2. The silencing of the TTCCs individually decreased tumor growth as measured by MRI and H&E staining. Silencing of TTCCs extended survival of mice in vivo. Silencing of TTCC decreases proliferation (Ki67) and increases apoptosis (Caspase 3). Our findings suggest T-type calcium channels contribute to tumor initiation and progression.
TMOD-11. A PREDICTIVE MICROFLUIDIC MODEL OF VASCULARIZED GLIOMA TUMORS TO ASSESS TRAFFICKING OF THERAPEUTICS ACROSS THE BLOOD-BRAIN BARRIER
Authors: Hajal Cynthia , Straehla Joelle , Offeddu Giovanni , Safford Hannah , Hammond Paula , Kamm Roger
Published: November 2021

Although important distinctions exist between subtypes of HGGs, all patients fare poorly with a 5-year survival of < 5%. The infiltrative growth of HGGs imposes significant challenges to treatment, with the presence of residual microscopic tumors post-surgery and hampered chemotherapeutic penetration due to the blood-brain barrier (BBB), a highly selective endothelium regulating transport between blood and brain. Moreover, current preclinical models are costly, low throughput, and often fail to predict drug performance in the clinic. There is thus an increasing need for in vitro models of HGG tumors, surrounded by a realistic BBB vasculature, to recapitulate therapeutic trafficking. To this end, we engineered a high-throughput microfluidic model composed entirely of human cells where HGG spheroids are embedded in a BBB microvascular network of endothelial cells, pericytes, and astrocytes. Tumors co-opt the vasculature as observed in patients and BBB permeability measurements with perfused dextran demonstrate unaltered paracellular transport near and far from the tumors. Lipoprotein receptor protein 1 (LRP1) expression, however, is increased near HGG spheroids. These results were leveraged to synthesize layer-by-layer nanoparticles with angiopep-2 ligands exhibiting high affinity to LRP1 for targeted delivery. Angiopep-2 nanoparticles displayed the largest permeability across the BBB near tumors compared to bare nanoparticles. Knock-down of LRP1 in the BBB-HGG model decreased angiopep-2 nanoparticle permeability confirming LRP1-mediated transport. We next assessed the therapeutic implications of our findings by encapsulating cisplatin in the particles. Administration of cisplatin-loaded angiopep-2 nanoparticles resulted in significant tumor shrinkage with targeted apoptosis in the tumor area compared to bare cisplatin nanoparticles or free cisplatin which damaged the surrounding healthy BBB vessels. Validations in orthotopic tumor-bearing mice are ongoing. In summary, we propose a novel preclinical model with a functional human BBB vasculature surrounding HGG tumors for high-throughput investigations and validate that this platform predicts the transport of targeted drug-loaded carriers.
TMOD-17. A NOVEL GLIOBLASTOMA INVASION MODEL USING HUMAN BRAIN SLICE CULTURES
Authors: Ravi Vidyha , Joseph Kevin , Beck Jürgen , Schnell Oliver , Hofmann Ulrich , Heiland Dieter Henrik
Published: November 2021

OBJECTIVE

Glioblastoma (GBM) is among the most common of malignant brain tumours, with a median post-surgical survival of less than one year. Over the past several decades, therapies that appeared promising in mice models have failed during clinical trials due to the differences encountered during translation of research from model organisms to humans. To partially mitigate these difficulties in translation, we present a human cortical organotypic culture based GBM model, which allows us to manipulate individual components of the tumour environment in order to investigate the influence of different cell types in the immunosuppressive tumour microenvironment.

METHODS

Human neocortical tissue (at least 2 cm away from the tumour core) or entry cortex from epilepsy surgery guided by intraoperative neuro navigation, was cultured for up to 14 days post resection using an optimized medium. The cultured tissue was further injected with patient derived human GBM cells to create an ex vivo human model of glioblastoma model. The role of astrocytes in the tumour microenvironment was studied using microglia loss of function model.

RESULTS

Our established human neo-cortical slice model can recapitulate an in-vivo characteristics of glioblastoma from functional and imaging aspect. Our data corroborate differences between astrocytes in human and murine models in different reactive states, shows that the glioblastoma microenvironment can be difficult to be accurately modelled using murine models. Results from our human microglia depletion model, provided ample evidence that complex interaction of astrocytes and microglia cells, promotes an immunosuppressive environment in Glioblastoma by releasing high concentration of IL10 and TGFbeta (p< 0.001).

CONCLUSION

Our model therefore has potential applications to the fields of neuroscience, neuro-oncology, and pharmacotherapy.
TMOD-23. MODELING PEDIATRIC BRAIN CANCER WITH HUMAN ORGANOIDS
Authors: Tiberi Luca
Published: November 2021

Among children/infant brain tumors, Medulloblastoma (MB) is the most common and stands as a cause for a high percentage of morbidity and mortality among patients During the past few years, studies on human MB have uncovered the existence of four major MB groups: WNT, SHH, Group3 and Group4. Patients with Group3 MB currently have the worst outcome among the four groups, and nearly 50% are metastatic at the time of diagnosis. In the last 3 years in our laboratory, we have developed a novel pediatric Medulloblastoma organoid model. We generated human iPSC-derived cancer organoids upon c-MYC/OTX2 and C-MYC/Gfi1 overexpression, mimicking human MB genetic alterations. Furthermore, the use of DNA methylation signature in combination with MB-specific markers analysis indicates that our organoid-based cancer model recapitulates several features of human MB. Now, we are taking advantage of this technology to produce novel brain cancer organoids that we are using to address cancer biology questions.
TMOD-26. MYC OVEREXPRESSION AND SMARCA4 LOSS IN GRANULE CELL PRECURSORS COOPERATE TO DRIVE MEDULLOBLASTOMA FORMATION IN MICE
Authors: Göbel Carolin , Holdhof Dörthe , Schoof Melanie , Kresbach Catena , Schüller Ulrich
Published: November 2021

Mutations in SMARCA4 are frequently identified in medulloblastoma, the most common pediatric malignant brain tumor. However, the functional significance of these mutations and their suitability as a therapeutic target remain largely unclear. Medulloblastomas are divided into 4 subgroups according to their localization, molecular biology, and clinical course: WNT, SHH, Group 3, and Group 4. Group 3 medulloblastomas are associated with the poorest outcome and frequently show amplifications of the oncogene MYC. Additionally, SMARCA4 is mutated in around 15 % of cases. The few mouse models developed for this entity so far all involve the overexpression of MYC, mostly in combination with other drivers. However, none of these models include alterations in Smarca4. In our approach, we combined an overexpression of MYC with a loss of SMARCA4 in granule cell precursors, which successfully induced tumor formation in mice. For this purpose, granule cell precursors were isolated from 7-day-old Math1-creER T2 ::Smarca4 fl/fl pups after tamoxifen induced loss of SMARCA4. MYC overexpression was achieved by lentiviral transduction and transduced cells were transplanted into immunodeficient CD1 nu/nu mice. Preliminary results within a small cohort showed tumor formation in 5/19 transplanted mice (26 %) after 6 months. Immunohistochemically, tumors all stained negative for SMARCA4. In a next step, additional cohorts will elucidate if tumor development is indeed accelerated by or even dependent on the loss of SMARCA4. Additionally, the neoplastic potential of tumor cells will be verified with the aid of secondary recipient mice. To evaluate to what extent the generated tumors are comparable to human Group 3 medulloblastomas, tumors will be extensively analyzed on a morphological, transcriptional, and epigenetic level. Altogether, we hope to establish a suitable mouse model for SMARCA4 mutated Group 3 medulloblastoma that will help to elucidate the role of SMARCA4 in tumor development and to identify new therapeutic targets.
TMOD-30. NTRK2 SPLICE VARIANT, TRKB.T1, LINKS NEUROBIOLOGY, EMBRYONIC DEVELOPMENT, AND ONCOGENESIS
Authors: Pattwell Siobhan , Arora Sonali , Nuechterlein Nicholas , Zager Michael , Loeb Keith , Cimino Patrick , Holland Nikolas , Bolouri Hamid , Ozawa Tatsuya , Haffner Michael , Cao Junyue , Shendure Jay , Holland Eric
Published: November 2021

Temporally regulated alternative splicing choices are vital for proper development yet the wrong splice choice may be detrimental. Here we highlight a novel role for the neurotrophin receptor splice variant TrkB.T1 in neurodevelopment, embryogenesis, transformation, and oncogenesis across multiple tumor types in both humans and mice. TrkB.T1 is the predominant NTRK2 isoform across embryonic organogenesis and is highly expressed in a wide range of adult and pediatric tumors. Further, forced expression of TrkB.T1 causes multiple solid and non-solid tumors in mice in the context of tumor suppressor loss. These results highlight a unique role for the neurotrophin receptor splicing in development and oncogenesis and underscore the need for considering alternative splicing and transcript level data in neuroscience, developmental biology, and oncology research.
BRMP-03. Pituitary carcinoma: a case of dramatic response to immunotherapy (ipilimumab + nivolumab) after failure with temozolomide
Authors: Shah Sanjit , Manzoor Saima , Rothman Yehudit , Hagen Matthew , Prater Luke , Golnik Karl , Mahammedi Abdelkader , Lin Andrew , Bhabhra Ruchi , Forbes Jonathan , Sengupta Soma
Published: November 2021

INTRODUCTION

Pituitary carcinoma (PC) accounts for just 0.1% of all pituitary tumors, often recurs following resection, and has a median reported survival of 1 year. Current treatment guidelines are not standardized but combine surgical resection, radiation therapy, and chemotherapy [1]. Temozolomide is the only chemotherapeutic with documented effectiveness, and the only recommended agent for aggressive pituitary carcinomas in ESE clinical guidelines [3]. CASE: A 57-year-old male presented with visual deterioration over a three-month period. Ophthalmologic evaluation revealed bitemporal visual field deficits. MRI brain W/WO demonstrated a sellar mass suspected to be pituitary macroadenoma with displacement of the stalk and optic nerve impingement (Figure 1a). The patient underwent stereotactic endoscopic transsphenoidal resection of the mass [2]. Postoperative MRI demonstrated gross total resection (Figure 1b). Pathology revealed a sparsely granulated corticotroph-adenoma with malignant transformation (early in-situ PC). Immunohistochemistry showed LOE of MLH1 and PMS2 in the tumor cells; Genetic analysis revealed MGMT methylation. Proton therapy was recommended given the elevated Ki67 index (75%) and p53 positivity. Before radiotherapy, there was no evidence of residual tumor or metastasis radiographically. He received 6600cGy of radiation over 33 fractions. Surveillance MRI showed recurrence at 21 months postoperatively, and temozolomide was initiated. However, MRI demonstrated marked progression after 3 cycles, and at 44 months, he developed a new 6th nerve palsy (Figure1c). Next-generation sequencing using the MSK-IMPACT platform identified somatic mutations in MLH1 Y548lfs*9 and TP53 R337C[4]. Immunotherapy with ipilimumab/nivolumab was initiated [5], and the patient noted resolution of his third nerve palsy soon after. MRI demonstrated a dramatic response with only minimal residual tumor burden (Figure1d).

CONCLUSION

PC is a rare tumor with frequent recurrence and a short median expected length of survival. Here we demonstrate the utility of immunotherapy in a single case report of PC. This treatment helped our patient survive well beyond the expected median life expectancy of this aggressive disease.
CNTM-02. Regulation of glioma-network integration by tumor mediated secretion of TSP-1
Authors: Negussie Mikias , Krishna Saritha , Hervey-Jumper Shawn
Published: November 2021

Glioma exists in the complex neural circuitry of the brain, making the interface between neoplastic and healthy neurons and glia potentially damaging to long range neural networks and stimulatory to tumor growth. Thrombospondin-1 (TSP-1), an astrocyte derived neurogenic factor expressed by glia of the normal brain, has been found to be upregulated in intratumoral regions with high network functional connectivity (HFC). This modified cell signaling represents cancer cell hijacking of normal physiology with direct impact on tumor biology. There is emerging evidence that neuronal activity influences glioma proliferation and gliomas promote neuronal hyperexcitability. In humans, we have recently shown that bidirectional cellular interactions between gliomas and neurons alter cognitive circuit dynamics and ultimately patient survival. Previously, a subpopulation of human high-grade glioma cells which are enriched for tumor cells with synaptogenic potential were identified (HFC-IHDwtGBM). We plan to study the mechanisms of TSP1 signaling in three different established glioma models (1) HFC-IDHwtGBM hippocampal neuron co-culture, (2) HFC-IDHwtGBM + induced neuron organoids, (3) patient derived xenografts (PDX) for in vivo GCaMP calcium imaging. This project aims to test the hypothesis that increased TSP-1 secretion from HFC-IHDwtGBM cells plays a central role in the maintenance of an invasive and proliferative tumor phenotype when compared with LFC-IHDwtGBM PDX. We hope our study guides future work focused on preventing the infiltration of tumor cells into healthy brain tissues.
FLGS-03. Fluorescein sodium-guided biopsy or resection in patients with contrast enhancing brainstem lesion in MRI
Authors: Lin Fuhua , Chen Zhenghe , Zhang Xiangheng , Mou Yonggao
Published: November 2021

BACKGROUND

It is challenging to resect or just biopsy the lesions in the brainstem, due to the essential function of the surfaces and limited space. Neuro-navigation is not always reliable and stereotatic biopsy is infrequently inconclusive due to small or inadequate samples. We want to share our experiences in the application of fluorescein sodium in surgery on patients with brainstem lesion which is contrast enhancing in MRI.

METHODS

Between January 2017 and June 2021, 5 patients with brainstem lesion underwent fluorescein sodium-guided surgery in neurosurgery department of Sun Yat-sen University Cancer Center. After injection of low dose of sodium fluorescein (3 mg/kg), the lesions with strong fluorescence staining were identified as the target area for biopsy or resection.

RESULTS

5 consecutive patients (aged 6–47 years) with brainstem lesions prospectively underwent fluorescein sodium-guided surgery. The lesions were located in pontine in 3 patients and in the medulla in 2 patients. Gross total resection was achieved in 2 patients, and partial resection in the other 3 patients. In all patients, a pathological diagnosis was obtained (4 gliomas and 1 metastasis from non-small cell lung carcinoma) without severe complications, including mild facial or abduct nerve palsy in 3 patients. And all the specimens with strong fluorescence staining sent for pathology were proved to be tumorous.

CONCLUSION

Fluorescein sodium-guided technique was helpful to locate the lesion in brainstem which was contrast-enhanced in MRI. It was effective and safe to figure out an ideal trajectory to avoid damage of the crucial structures and improve the diagnostic rate.
IOTG-02. Glioma Supra Marginal Incision Trial (G-SUMIT): a phase II pilot randomized control trial to assess the feasibility of “supra-marginal” surgical resection of malignant glioma
Authors: Lai Carolyn , Mansouri Alireza , Scales Damon , Perry James , Sahgal Arjun , Pirouzmand Farhad
Published: November 2021

High grade gliomas are the most common primary malignant brain tumor in adults having a median survival of only 13–16 months. This is despite the current standard of maximal safe surgical resection followed by fractionated radiotherapy and chemotherapy. Extending the tumor resection limit beyond the GAD-enhancing margin (i.e. supra-marginal resection) could in principle provide an added survival benefit as it has been shown that >80% of post-operative tumor recurrence is within a 2cm region surrounding the original GAD-enhancing margin. However, this must be weighed against the risk of potential damage to functional brain tissue. In this phase II pilot randomized control trial (RCT), we aim to assess the feasibility of “supra-marginal” resection extending 1cm beyond the enhancing tumor in adults with radiographic evidence of GAD-enhancing intra-axial tumour consistent with high grade glioma in a safe anatomical location and a Karnofsky Performance Score > 60. With six academic centres participating, we aim to enroll 72 patients over two years. Currently, four patients have already been enrolled in the first four months. Primary outcomes include evaluating the feasibility of performing a large-scale trial with regards to recruitment, allocation and outcome documentation as well as safety data. Secondary outcomes include determining if there is an increased survival benefit with supra-marginal resection and impact on quality of life. Our pilot RCT will test the feasibility of comparing standard gross total resection of GAD-enhancing tumour and supra-marginal resection to prepare for a larger definitive multicentre RCT.
Long-term contracts and the Unidroit PICC: towards a realistic regulation
Authors: Zuñiga Peralta Raul F
Published: November 2021

The 2016 Unidroit Principles of International Commercial Contracts (PICC) were the first instrument that explicitly regulated long-term contracts in international commerce. Its main goal was to actualize uniform contract law for the emerging needs of international commerce. Despite this effort, scholars have briefly researched how uniform contract law instruments address international commerce as an economic reality or whether the PICC’s attempt is adequate. The gap in uniform contract law’s—particularly the PICC’s—literature on long-term contracts is odd compared to the completeness of economic literature on the matter. After revealing the pitfalls of the PICC’s regulation, demonstrating the convenience of a thorough review of the economics of long-term contracts, this article elaborates on the necessary character of the connection between uniform contract law and economics. It further reviews the economic research on the factors that prompt long-term contracting and the mechanisms that economic agents designed to address their needs. The overhaul reveals that two paradigmatic economic structures—competitive and cooperative—generally determine the design of long-term contracts. Finally, the article addresses the consequences of including the paradigmatic economic structures of long-term contracts in the PICC rules on contract interpretation and gap-filling.
Why Should Nurses Care About the Supreme Court?
Authors: Dorsen Caroline , Harney Hannah , LeDuc Claudia
Published: November 2021

Many cases have direct and indirect bearing on health care policy and public health.
Trends in Life Expectancy After Allogeneic Blood or Marrow Transplantation
Authors: Todd Betsy
Published: November 2021

Life expectancy for blood or marrow transplant recipients has improved over the past 40 years.
Impact of COVID-19 on Undergraduate Nursing Education: Student Perspectives
Authors: Head Morgan L. , Acosta Samantha , Bickford Emma G. , Leatherland Malia A.
Published: November 2021

The COVID-19 pandemic has taken higher education in general into unprecedented times. The rapid transition from in-person to online teaching and learning proved to be difficult for students, educators, and administrators. It could be argued that medical and nursing education had an even more difficult task of determining how to effectively teach the provision of health care—a fundamentally in-person, hands-on endeavor—online. The purpose of this paper is to explore the impact that COVID-19 had on undergraduate nursing education and identify lessons learned as a result. Nursing student perspectives from 2 Midwestern universities were compiled and analyzed to identify challenges, interventions performed, and key lessons learned.
Factors Associated With Increased Opioid Use During the COVID-19 Pandemic: A Prospective Study of Patients Enrolled in Opioid Agonist Treatment
Authors: Rosic Tea , Naji Leen , Sanger Nitika , Marsh David C. , Worster Andrew , Thabane Lehana , Samaan Zainab
Published: November 2021

Objectives

The opioid use disorder (OUD) crisis in North America has become “an epidemic within a pandemic” in the context of the COVID-19 virus. We aimed to explore the association between the COVID-19 pandemic and changes in opioid use patterns among patients receiving treatment for OUD.

Methods

We used prospectively collected data from 456 patients attending 31 opioid agonist clinics across Ontario, Canada. All included participants underwent routine urine drug screens (UDSs) both before and after the onset of the COVID-19 pandemic. A paired sample t-test was used to compare the proportion of opioid-positive UDSs collected pre- and post-pandemic, and linear regression analysis was used to explore factors associated with this change.

Results

Participants had a mean age of 39.9 years (standard deviation = 10.9), 52%were male, and 81%were receivingmethadone treatment. The percentage of opioid-positive UDSs increased significantly during the pandemic, on average by 10.6% (95% confidence interval [CI] 8.17, 12.95, P < 0.001). Continued opioid use before the pandemic was associated with 9.43% increase, on average, in the percentage of opioid-positive UDSs during the pandemic (95% CI 3.79, 15.07). Self-reported past-month cocaine (adjusted betacoefficient 6.83, 95% CI 0.92, 12.73) and amphetamine (adjusted beta-coefficient 13.13, 95% CI 5.15, 21.1) use at study entry were also associated with increases in opioid-positive UDSs.

Conclusions

Increased opioid use is one measure of the negative impact the COVID-19 pandemic has had on individuals with OUD, an already marginalized population. Understanding factors associated with worse outcomes is essential to ensuring that treatment programs appropriately adapt to better serve this population during the pandemic.