bluuebunny/crossref_metadata_2025_split huggingface dataset:
EXTH-36. PI3K INHIBITION IN CONJUNCTION WITH THE KETOGENIC DIET REDUCES GROWTH AND NEUROINFLAMMATION IN PEDIATRIC HIGH-GRADE GLIOMA
Authors: Noch Evan , Yim Isaiah , Cantley Lewis 
Published: November 2019

Abstract
Pediatric high-grade glioma remains a poorly treatable disease with high mortality. Targeted therapies have gained interest in this disease, but efficacy is limited by therapeutic resistance, often because of tumor heterogeneity. Phosphoinositide 3-kinase (PI3K) inhibitors represent a strong drug class for pediatric glioma, but their use is associated with insulin feedback that reactivates the PI3K pathway and drives therapeutic resistance. Here, we target insulin feedback that is the primary mechanism of PI3K inhibitor-related therapeutic resistance in pediatric high-grade glioma using the ketogenic diet. We treated patient-derived pediatric high-grade glioma stem cells with vehicle or the pan-PI3K inhibitor, BKM-120, in conjunction with phenformin to decrease glucose utilization. These cells exhibited 65% less proliferation when exposed to BKM-120 and phenformin. We treated NOD scid gamma (NSG) mice containing patient-derived pediatric high-grade glioma xenografts with vehicle or BKM-120 on a regular or ketogenic diet to determine whether reducing insulin feedback increases BKM-120 efficacy. Mice with intracranial glioma xenografts survived longer when treated with BKM-120 on the ketogenic diet than with BKM-120 or the ketogenic diet alone. We measured pro-inflammatory cytokines in glioma cells treated with BKM-120 and phenformin in comparison to vehicle-treated cells to determine their effect on neuro-inflammation. We also applied conditioned medium from glioma cells treated with BKM-120 and phenformin to cortical neurons to measure oxidative stress. We found that phenformin reduced the production of pro-inflammatory cytokines, including TNF-alpha, IFN-gamma, IL-1beta, and IL-6, by BKM-120-treated glioma cells. Cortical neurons treated with conditioned medium from BKM-120- and phenformin-treated glioma cells exhibited less oxidative stress than those treated with BKM-120 alone. Our results demonstrate that lowering glucose utilization and insulin feedback increases efficacy of PI3K inhibition and decreases neuro-inflammation. By using the ketogenic diet to reduce systemic glucose levels, this strategy may enhance efficacy and reduce morbidity of PI3K inhibitors in this population.
EXTH-37. A NOVEL TRANSDUCER ARRAY LAYOUT FOR DELIVERING TUMOR TREATING FIELDS TO THE SPINE
Authors: Naveh Ariel , Yesharim Ofir , Bomzon Ze’ev 
Published: November 2019

Abstract
Tumor Treating Fields (TTFields) are an antimitotic technology utilising electric fields to disrupt mitosis in cancer cells. TTFields are currently approved by the FDA for the treatment of Glioblastoma Multiforme (GBM) and Malignant Pleural Mesothelioma (MPM). TTFields are delivered through 2 pairs of transducer arrays placed on the patient’s skin. Each pair delivers TTFields in a single direction, and the pairs are placed to provide perpendicular field. Preclinical studies show that 1V/cm is the clinical threshold for the treatment to be effective. Some types of cancers send metastases to the spinal cord and CSF, i.e. leptomeningeal disease. The purpose of this study was to find transducer array layouts that deliver TTFields to the spine at therapeutic intensities of above 1 V/cm. Computational simulations testing the delivery of TTFields to the spine were performed using the Sim4Life 4.0 (ZMT Zurich) computational platform, and the Duke 3.1 and Ella 3.0 (ITI’S, Zurich) realistic computational models of a male and female respectively. “Standard” layouts in which a pair of arrays are placed on the front and back of the patient and second pair on the lateral aspects of the patient failed to deliver TTFields at therapeutic intensities to the spinal cord. This is probably because the spinal cord is surrounded by the CSF and spine, which shunt the electric fields from reaching the spinal cord. However, field intensities above 1 V/cm were observed when delivering TTFields when both arrays were placed on the patients back, with a first array placed close to the neck, and second array placed towards the thighs. In this case, the spinal cord and surrounding CSF act as a conductive cable, directing the electric field along the spine. This novel layout opens the possibility for treating cancerous disease along the spine.
EXTH-41. A NANOPARTICLE-BASED CANCER-SELECTIVE GENE TRANSFER STRATEGY FOR LOCALIZED THERAPY OF MALIGNANT HIGH GRADE GLIOMAS
Authors: Rao Divya , Phal Ashish , Naga Varun , Negron Karina , Oh Yumin , Hanes Justin , Soo Suk Jung 
Published: November 2019

Abstract
Treatment for malignant high grade gliomas entails surgery, followed by chemotherapy and/or radiation. Despite the intensive care, there is a ~90% recurrence rate. This is attributed to suboptimal efficacy of treatments in tackling widespread cancer cells. We have previously developed nanoparticles that provide widespread therapeutic distribution both in healthy and tumor tissues, but are incapable of differentiating between them. This limitation applies to the current standard-of-care and state-of-the-art gene therapies. Here, we evaluate the efficacy of DNA nanoparticles carrying promoters that drive transgene expression specifically in tumor cells to achieve widespread yet cancer-selective gene transfer in high grade gliomas. To identify tumor-specific promoters, we used ELISA to confirm elevated expression of proteins previously reported to be upregulated in tumor tissue. We observed that expression of survivin in cancer cells was significantly greater than that of other cancer-rich proteins, exhibiting two orders of magnitude greater levels in rodent and human cancer cells compared to their respective healthy cells. Furthermore, the CMV promoter mediated similarly high expression in healthy cells, whereas the level achieved by the survivin promoter was significantly lower, if not negligible, suggesting its tumor specificity. Likewise, CMV-driven plasmids delivered into the brain by the nanoparticles mediated virtually identical volumetric distribution of transgene expression in both normal and tumor tissues in vivo. In contrast, nanoparticles carrying survivin-driven plasmids provided widespread transgene expression only in an orthotopically established tumor, but not healthy brain tissue. Additionally, we demonstrate therapeutic efficacy in an established brain tumor model using the DNA nanoparticles carrying survivin promoter-driven plasmids expressing a therapeutic protein. We identified survivin promoter as a lead TSP and confirmed its ability to mediate highly efficient and widespread but cancer-selective transgene expression with the aid of our nanoparticles uniquely designed to penetrate in healthy and tumor tissues.
EXTH-53. TUMOR TREATING FIELDS LEADS TO CHANGES IN MEMBRANE PERMEABILITY AND INCREASED PENETRATION BY ANTI-GLIOMA DRUGS
Authors: Chang Edwin , Patel Chirag , Beinat Corinne , Young Caroline , Flores Thomas , Zeng Yitian , Joubert Lydia , Arami Hamed , Natarajan Arutselvan , Sinclair Robert , Gambhir Sanjiv 
Published: November 2019

Abstract

BACKGROUND
Efforts are underway to uncover novel, unorthodox therapies against glioblastoma (GBM). Tumor treating fields (TTFields) disrupt mitotic spindle formation and stymie proliferation in tumor cells. Combining TTFields with Withaferin A, synergistically inhibited proliferation in GBM. We wished to uncover the relevant mechanism.

METHODS
Human and murine GBM cells (GBM2, GBM39, U87-MG, KR158B) were isolated from primary tumors. Cells were engineered to stably express firefly luciferase (fLuc). Proliferation was assessed by bioluminescence imaging (using D-Luciferin as a substrate for fLuc) or cell counting. Dextran-FITC binding and scanning electron microscopy (SEM) studies were used to probe effects on cellular membranes.

RESULTS
TTFields (200 kHz, 4 V/cm) significantly inhibited growth of cells (n=3/time point, p≤0.02; 2-way ANOVA, no TTFields vs. TTFields). Combination of Withaferin A with TTFields significantly inhibited growth of glioma cells synergistically beyond that of Withaferin A or TTFields alone (p< 0.01, at least n=3 experiments). Bioluminescence imaging suggested alterations in membrane configuration when cancer cells were exposed to TTFields. This was validated with observations of greater fluorescence of membrane-associating Dextran-FITC to U87-MG cells that were subjected to TTFields (p< 0.01, 2-way ANOVA, TTFields vs. no TTFields, n=3 experiments). SEM revealed significantly greater and larger number of holes on the membrane surface of TTFields-exposed U87-MG cancer cells (53.5±19.1 holes per field of view and mean size=240.6±91.7 nm2) compared to unexposed cells (23.9±11.0 holes per field of view and mean size=129.8±31.9 nm2, p< 0.005: TTFields exposed vs. non-exposed, n=3 samples, univariate Mann-Whitney test).

CONCLUSION
The findings suggest a novel combinatorial approach to treat GBM in a manner that is better than single treatment (drug or TTFields) alone and that is synergistic. Synergy is achieved through TTFields inducing increased permeability on membranes thus conferring greater accessibility to drug. Such a strategy is thus a promising candidate for future clinical translation in glioblastoma.
EXTH-56. MEDULLOBLASTOMAS RESPOND TO CDK4/6 INHIBITION WITH NANOPARTICLE-DELIVERED PALBOCICLIB WITH ALTERED S-PHASE PROGRESSION
Authors: Dismuke Taylor , Lim Chaemin , Gershon Timothy 
Published: November 2019

Abstract
CDK4/6 inhibition is a promising therapy for medulloblastoma, one of the most common malignant pediatric brain tumors. To improve pharmacokinetics, we developed a polyoxazoline nanoparticle-encapsulated formulation of the FDA-approved CDK4/6 inhibitor palbociclib (POx-palbo). We then administered POx-palbo to transgenic medulloblastoma-prone GFAP-Cre/SmoM2 mice, to determine the efficacy and mechanisms of action and resistance. We found that POx-palbo slowed tumor progression, but consistently failed to be curative. Further analysis showed that while CDK4/6 inhibition acutely blocked G1 cells from re-entering the cell cycle, this effect wore off within hours of drug administration. However, flow cytometric analysis of EdU uptake hours after palbociclib demonstrated aberrant S-phase with reduced rate of DNA synthesis. This POx-palbociclib-induced alteration of S-phase progression seems to remain true at later time points even when we observed that palbociclib G1/S inhibition began to decrease. Based on these data, we propose that the combinational therapy of POx-palbociclib and S-phase targeting agents will further improve treatment. Faulty tumor cell cycle progression in the presence of Pox-palbociclib may give increased window to target the S-phase for irreversible cell-cycle exit.
EXTH-63. LIPOSOMAL DELIVERY OF FERRITIN HEAVY CHAIN (FTH1) siRNA RESULTS IN INCREASED RADIATION SENSITIVITY IN PATIENT DERIVED GLIOMA INITIATING CELLS
Authors: Ravi Vagisha , Abraham Thomas , Madhankumar Achuthamangalam , Slagle-Webb Becky , Pandya Bhavyata , Connor James 
Published: November 2019

Abstract
Glioblastoma (GBM) is the most lethal and incurable brain cancer. Despite maximum treatment, high recurrence rates result in median survival of less than 2 years. A subset of treatment resistant cells within GBM known as glioma initiating cells (GICs) are implicated in recurrence and exhibit ferritin overexpression. High expression of ferritin is known to be associated with poor overall survival in GBM patients. Our previous finding showed that downregulation of the ferritin heavy chain subunit (FTH1) enhanced treatment sensitivity in astrocytoma cells. Recently, functional importance of FTH1 in GICs was demonstrated by shRNA silencing leading to ablation of tumorigenic ability. We therefore posited that disrupting iron metabolism through FTH1 knockdown would radiosensitize GICs. Thus we developed multivalent cationic liposomes that enabled delivery of FTH1 siRNA to patient derived GICs isolated from pro-neural (PN) and mesenchymal (Mes) GBM. In both subtypes, FTH1 loss led to increased apoptosis and reduced cell viability. When exposed to radiation, PN GICs were unable to repair and recover from DNA damage, leading to a further decrease in cell viability and a complete loss of reproductive clonogenic potential unlike their more radioresistant Mes counterparts. Moreover, expression of stem cell marker Nestin was markedly reduced in PN but not Mes GICs. Thus, FTH1 loss is detrimental to both GIC subtypes, it seems to be critical for maintaining stemness and radiation resistance of PN GICs. These findings further support the viability of FTH1 as a therapeutic target in GBM.
EXTH-70. ENHANCEMENT OF ANTITUMOR ACTIVITY BY USING 5-ALA–MEDIATED SONODYNAMIC THERAPY TO INDUCE APOPTOSIS AND NECROSIS IN A MOUSE GLIOMA MODEL
Authors: Suehiro Satoshi , Ohnishi Takanori , Inoue Akihiro , Yamashita Daisuke , Nishikawa Masahiro , Ohue Shiro , Kunieda Takeharu 
Published: November 2019

Abstract

OBJECTIVE
High invasiveness of malignant gliomas frequently causes local tumor recurrence. To control such recurrence, novel therapies targeted toward infiltrating glioma cells are required. Here, we examined cytotoxic effects of sonodynamic therapy (SDT) combined with a sonosensitizer, 5-aminolevulinic acid (5-ALA), on malignant gliomas both in vitro and in vivo.

METHODS
In vitro cytotoxicity of 5-ALA-SDT was evaluated in U87 and U251 glioma cells and in U251Oct-3/4 glioma stemlike cells. Treatment-related apoptosis was analyzed using flow cytometry. Intracellular reactive oxygen species (ROS) were measured and the role of ROS in treatment-related cytotoxicity was examined. Effects of 5-ALA-SDT with high-intensity focused ultrasound (HIFU) on tumor growth, survival of glioma-transplanted mice, and histological features of the mouse brains were investigated.

RESULTS
The 5-ALA-SDT inhibited cell growth and changed cell morphology. Flow cytometric analysis indicated that 5-ALA-SDT induced apoptotic cell death. The 5-ALA-SDT generated higher ROS than in the control group, and inhibition of ROS generation completely eliminated the cytotoxic effects of 5-ALA-SDT. In the in vivo study, 5-ALA-SDT with HIFU greatly prolonged survival of the tumor-bearing mice compared with that of the control group (p < 0.05). Histologically, 5-ALA-SDT produced mainly necrosis of the tumor tissue in the focus area and induced apoptosis of the tumor cells in the perifocus area around the target of the HIFU-irradiated field. Normal brain tissues around the ultrasonic irradiation field of HIFU remained intact.

CONCLUSIONS
The 5-ALA-SDT was cytotoxic toward malignant gliomas. Generation of ROS by the SDT was thought to promote apoptosis of glioma cells. The 5-ALA-SDT with HIFU induced tumor necrosis in the focus area and apoptosis in the perifocus area of the HIFU-irradiated field. These results suggest that 5-ALA-SDT with HIFU may present a less invasive and tumor-specific therapy, not only for a tumor mass but also for infiltrating tumor cells in malignant gliomas.
EXTH-71. IND-ENABLING CHARACTERIZATION OF ONC206 AS THE NEXT BITOPIC DRD2 ANTAGONIST FOR NEURO-ONCOLOGY
Authors: Prabhu Varun , Rahman Kawakibi Abed , Madhukar Neel , Garnett Mathew , McDermott Ultan , Benes Cyril , Wechsler-Reya Robert , Elemento Olivier , Stogniew Martin , Oster Wolfgang , DeMorrow Sharon , Allen Joshua 
Published: November 2019

Abstract
ONC201 is the first clinical bitopic antagonist of DRD2, an oncogenic receptor in brain and neuroendocrine tumors. ONC206, a derivative of ONC201 that shares the imipridone core structure, is also a bitopic DRD2 antagonist that exhibits enhanced non-competitive effects, high specificity, nanomolar potency, and disruption of DRD2 homodimers. Broad nanomolar efficacy of ONC206 (GI50 < 78-889nM, CellTitre-Glo, 72h) was observed in >1,000 GDSC cancer cell lines. Maximal ONC206 sensitivity was observed in pheochromocytoma, high-grade gliomas, neuroblastoma, medulloblastoma, sarcoma and cholangiocarcinoma cell lines exhibiting a DRD2+/DRD5- RNA expression signature. An exposure time of 48h at nanomolar concentrations was sufficient for maximal inhibition of tumor cell viability. ONC206 reduced the viability of normal human fibroblasts at higher doses (GI50 > 5µM), suggesting a wide therapeutic window. Antitumor efficacy without body weight loss was observed with 50 mg/kg weekly oral ONC206 in a dopamine-secreting HuCCT1 cholangiocarcinoma subcutaneous xenograft model. Biodistribution studies in Sprague-Dawley rats revealed a ~12 µM plasma Cmax with a systemic terminal half-life of ~6 hours upon a single oral dose of 50 mg/kg. Additionally, 5–10 fold higher ONC206 concentrations were observed in adrenal gland, bile duct, brain and bone marrow relative to plasma. Nanomolar concentrations were also observed in the CSF above DRD2 antagonism thresholds, unlike ONC201. GLP toxicology studies with weekly oral ONC206 in Sprague-Dawley rats and beagle dogs revealed no dose-limiting toxicities. Mild and reversible decreased body weight and/or body weight gain with no effects on food consumption were observed at the highest evaluated dose in both species. The highest non-severely toxic dose (HNSTD) was ≥ 16.7 mg/kg in dogs and ≥ 50 mg/kg in rats that exceeds efficacious doses in preclinical models. Using standard allometric scaling, a 90 mg starting dose of ONC206 was selected for the first-in-human clinical trial in biomarker-defined adult recurrent CNS tumors.
GENE-03. SPECIFIC SIGNATURES OF microRNA IN CEREBROSPINAL FLUID OF PATIENTS WITH PRIMARY BRAIN TUMORS AND METASTASES
Authors: Jancalek Radim , Smrcka Martin , Kopkova Alena , Sana Jiri , Vecera Marek , Oppelt Jan , Trachtova Karolina , Fadrus Pavel , Slaby Ondrej 
Published: November 2019

Abstract
Cerebrospinal fluid (CSF) baths extracellular environment of the central nervous system, and thus, it is ideal source of tumor diagnostic biomarkers like microRNAs (miRNAs), short non-coding RNAs involved in the pathogenesis of many cancers. As dysregulated levels of brain tumor specific miRNAs have been already observed in CSF, analysis of CSF miRNAs in brain tumor patients might help to develop new diagnostic platform. Next-Generation sequencing (NGS) was performed for analysis of small RNAs in 89 CSF samples taken from 32 glioblastomas (GBM), 14 low-grade gliomas (LGG), 11 meningiomas, 13 brain metastases and 19 non-tumor donors. Subsequently, according to NGS results levels of 10 miRNAs were measured in independent set of CSF samples (41 GBM, 44 meningiomas, 12 brain metastases and 20 non-tumor donors) using TaqMan Advanced miRNA Assays. NGS analysis revealed 22, 12 and 35 CSF miRNAs with significantly different levels in GBM, meningiomas, and brain metastases (adj.p < 0.0005, adj.p < 0.01, and adj.p < 0.005) respectively, in comparison with non-tumor CSF samples. Subsequent validation of selected CSF miRNAs has confirmed different levels of 7 miRNAs in GBM, 2 in meningiomas, and 2 in brain metastases compared to non-tumors. Panel of miR-30e-5p and miR-140-5p was able to distinguish brain metastases with 65% sensitivity and 100% specificity compared to non-tumor samples (AUC = 0.8167); panel of miR-21-3p and miR-196-5p classified metastatic patients with 78% sensitivity and 92 % specificity in comparison to GBM (AUC = 0.90854) and with 75% sensitivity and 83% specificity compared to meningiomas (AUC = 0.84848). We have observed that CSFs from patients with various primary brain tumors and metastases are characterized by specific miRNA signatures. This work was supported by the Ministry of Health, Czech Republic grant nr. NV18-03-00398 and the Ministry of Education, Youth and Sports, Czech Republic under the project CEITEC 2020 (LQ1601).
GENE-10. A SIMPLE AND EFFICIENT METHOD FOR GENERATING MULTI-ALLELIC INSERTION-DELETION MUTATIONS AND PRECISE DELETIONS IN PRIMARY HUMAN CELL CULTURES
Authors: Hoellerbauer Pia , Kufeld Megan , Arora Sonali , Wu Hua-Jun , Feldman Heather , Paddison Patrick 
Published: November 2019

Abstract
CRISPR-Cas9-based technologies have revolutionized experimental manipulation of the human genome by enabling generation of site-specific genetic alterations, such as insertion-deletion (indel) mutations. None-the-less, limitations of the delivery and efficacy of these technologies restrict their application in primary human cells. Here, we present a simple and effective method for fast and penetrant induction of multi-allelic indels and near-precise deletions (ranging from ~50bp to >50kbp) in primary human neural stem/progenitor cell (NPC) and brain tumor-derived stem-like cell cultures using the CRISPR-Cas9 system. We report that mono-, bi-, or multi-allelic (depending on ploidy) indel efficiencies of >90% can be routinely achieved within 3 days, without the need for pre-engineering cells to express Cas9 or isolating clones. As a result, this method enables the quick generation of a series of knockouts at different genomic loci, which we illustrate by successively targeting TP53, CDKN2A, PTEN, and NF1 in human NPC populations, where ³95% loss of protein expression is observed. RNA-seq analysis of these NPC knockout pools confirmed gene expression changes including p53 transcriptional and Rb-axis targets, as well as NF1-dependent repression of major histocompatibility complex class II gene expression. Given its simplicity, this method is readily adaptable to other primary mammalian cell types.
GENE-32. SYNTHETIC LETHAL INTERACTIONS WITH IDH1R132H IN GLIOMA STEM-LIKE CELLS
Authors: Ventosa Maria , Kadiyala Padma , Carney Stephen , Castro Maria , Lowenstein Pedro 
Published: November 2019

Abstract
Gliomas are the most frequently diagnosed human primary brain tumors. Mutations in Isocitrate Dehydrogenase (IDH) 1 occur in the vast majority of low grade gliomas and secondary high grade glioblastomas. A single amino acid missense mutation in IDH1 at arginine 132 (R132H) is an early event in tumor development. IDH1R132H leads to the production of the oncometabolite 2-R-2-hydroxyglutarate. However the exact roles played by IDH1R132H in the development and malignant transformation of the tumors remain unclear. Further studies are required to determine optimal therapeutic strategies to target the IDH1 mutated subsets of gliomas. New generation high-throughput genetic perturbation technologies make it possible to systematically identify the genes and pathways required for the survival and proliferation of mammalian cells. Herein, we present preliminary results from a CRISPR-dCas9 derived activation to drive the transcriptional activation of more than 23,000 coding genes in both wild type and mutant IDH1 patient-derived pediatric glioma cells. Based on an average of three viability screens per cell type, we analyzed the sgRNA library representation in the IDH1 mutated and non-mutated glioma cultures after the genome wide activation. We identified 1553 candidate genes that upon gain of function trigger the death of glioma cells harboring the IDH1 mutation. The analysis of these results further pinpoints the activation of the Cyclin E1 (CCNE1), the BCL2 Antagonist/Killer 1 (BAK1) and the Homeobox B13 (HOXB13) as the most significant synthetic lethal targets in IDH1R132H glioma cells. Interestingly, results from RNAseq showed a decreased expression of these genes in IDH1 mutated compared to non-mutated glioma cells. Thus, this viability screening aims to elucidate genes that interact with IDH1R123H and play a role in tumor cell fitness. The functional analysis of these candidate genes will allow us to uncover their contribution to the progression of IDH1 mutated gliomas.