bluuebunny/crossref_metadata_2025 huggingface dataset:
DDIS-36. BTP-7, A NOVEL PEPTIDE FOR THERAPEUTIC TARGETING OF MALIGNANT BRAIN TUMORS
Authors: von Spreckelsen Niklas , Ghotmi Yarah , Fadzen Colin , Wolfe Justin , Hartrampf Nina , Bergmann Sonja , Qu Yuan , Murrell Emily , Bononi Fernanda , Luyt Leonard , Lamfers Martine , Ligon Keith , Chiocca Ennio , Viapiano Mariano , Pentelute Bradley L , Lawler Sean , Cho Choi-Fong
Published: November 2019

High-grade gliomas are deadly cancers, and current standard-of-care has demonstrated limited success. The ability to specifically target glioma cells allows for the development of safer and more efficacious brain cancer therapy strategies. Brevican, a CNS-specific extracellular matrix protein is upregulated in glioma cells and its expression correlates with tumor progression. Particularly, a brevican isoform lacking glycosylation, B/bΔg is a unique glioma marker and not expressed in non-cancerous tissues. Therefore, B/bΔg represents a valuable target for anti-cancer strategies. Here, we describe the utilization of state-of-the-art platforms to screen a one-bead-one-compound combinatorial peptide library to discover a novel “B/bΔg-Targeting Peptides”, called BTP-7 that can bind B/bΔg with high affinity and specificity. BTP-7 displayed 260 nanomolar affinity for recombinant B/bΔg protein. Binding to a specific site on B/bΔg was confirmed in a competitive binding assay using BTP-7 functionalized with a UV-crosslinker and BTP-7 had little association with the fully glycosylated isoform of brevican (control). Scrambling of the BTP-7 sequence led to complete abrogation of B/bΔg binding. Furthermore, BTP-7 is preferentially taken up by B/bΔg-expressing glioma cells compared with non-expressing cells. We also discovered that BTP-7 can cross the blood-brain barrier in both the in vitro BBB organoid model and in mice. BTP-7 displayed 10x greater binding to intracranial GBM-6 tumors than control peptides, and 4x higher tumor uptake than in normal brain tissues. Conjugation of BTP-7 to camptothecin (an anti-tumor drug) via a cleavable linker led to increased DNA damage in intracranial GBM-6 tumors and prolonged survival in tumor-bearing mice. Our results show the potential of BTP-7 for the development of next-generation targeted therapeutics that could greatly benefit the outcome of patients with advanced brain cancer.
EPID-03. HISTOLOGY-SPECIFIC BRAIN TUMOR INCIDENCE AND SURVIVAL VARIES BY SEX
Authors: Dong Michelle , Cioffi Gino , Kruchko Carol , Ostrom Quinn , Lathia Justin , Rubin Joshua , Berens Michael , Connor James , Barnholtz-Sloan Jill
Published: November 2019

BACKGROUND

Significant sex differences exist in cancer, and males have higher incidence and lower survival compared to females for most cancers. No large-scale studies have systematically examined sex differences in incidence and survival across all primary brain histologies. We performed a comprehensive investigation of the differences in incidence and survival in patients diagnosed with primary malignant brain and other CNS tumors by specific histologies.

METHODS

Age-adjusted incidence rate ratios (IRR) and 95% confidence intervals (945% CI) were generated from the United States Cancer Statistics (USCS) Public Use Database. Data from the Surveillance, Epidemiology, and End-Results (SEER) program were used to calculate overall survival. Data was restricted to patients with histologically or radiologically confirmed, primary malignant tumors diagnosed between 2001 and 2015. Histological groupings were categorized based on the Central Brain Tumor Registry of the United States (CBTRUS). Cox proportional hazards models were used to calculate hazard ratios (HR) adjusted for age for males as compared to females.

RESULTS

Males exhibited higher incidence than females in all brain histologies except meningioma (IRR=0.83; 95% CI 0.73–0.93) and other neuroepithelial tumors (i.e. polar spongioblastomas and astroblastomas) (IRR=0.48; 95% CI 0.26–0.88). Males experienced better overall survival in germ cell tumors, cysts and heterotopias (HR=0.68; 95% CI 0.49–0.94) compared to females, but were observed to have lower survival in all other histologies. Survival was lowest for males among patients with nerve sheath tumors (HR=2.32; 95% CI 1.31–4.12) and other neoplasms related to the meninges (e.g. chondrosarcomas and chordomas) (HR=2.23; 95% CI 1.24–3.99). Survival in meningioma patients was significantly higher in females (HR=1.49; 95% CI 1.25–1.77). Patients with glioblastomas, had a slightly worse survival outcome in males (HR=1.02, 95% CI 1.00–1.05).

CONCLUSION

Understanding the role of sex differences is critical for addressing sex based inequalities and needs to be taken into account in clinical paradigms.
EPID-09. PROGNOSTIC FACTORS IN ADULT PATIENTS WITH PRIMARY INTRACRANIAL EPENDYMOMAS: A POPULATION-BASED STUDY
Authors: Yang Helen , Malik Abdullah , Das Sunit
Published: November 2019

BACKGROUND

Outcomes for patients with intracranial ependymoma remain poor in the current era of cancer treatment. This study aims to investigate the prognostic value of demographic and clinical variables to predict survival using the largest current database of patients with intracranial ependymoma.

METHODS

The Surveillance, Epidemiology and End Results (SEER) registry was queried for prognostic factors and survival outcomes of adult (≥18 years) patients diagnosed with intracranial ependymoma from 2004–2016. Survival was estimated using Kaplan Meier curves. Cox proportional hazards modeling was used to identify correlates of survival.

RESULTS

We identified a cohort of 229 primary intracranial ependymoma patients. The cohort showed a slight male predominance (52%) and had a mean age of 43 ± 17 years. 107 patients (47%) had WHO grade II tumors and 122 patients (53%) had WHO grade III tumors. One year survival was 85% for the entire cohort. Increasing age at diagnosis (HR: 1.05, 95% CI: 1.03–1.07) and WHO grade III tumor (HR: 4.20, 95% CI: 2.02–8.75) were independently associated with mortality after adjusting for age, sex, tumor location, extent of surgery, use of radiation therapy, and use of chemotherapy. Use of radiation therapy was associated with better one-year survival in cases of gross total resection (GTR) and subtotal resection (STR). Use of chemotherapy was not associated with mortality in the adjusted analysis (HR: 2.16, 95% CI: 0.96–4.84).

CONCLUSION

Our results suggest that age at diagnosis and tumor grade are independent factors associated with mortality in adult patients with intracranial ependymoma. Furthermore, use of chemotherapy was not shown to decrease mortality. These findings help guide future prognostic model making and therapeutic strategies designed by health care professionals.
EPID-10. VENOUS THROMBOEMBOLIC EVENTS IN GLIOBLASTOMA PATIENTS: AN EPIDEMIOLOGICAL VIEW
Authors: Gramatzki Dorothee , Roth Patrick , Le Rhun Emilie , Rushing Elisabeth , Rohrmann Sabine , Stahel Rolf , Weller Michael
Published: November 2019

BACKGROUND

Venous thromboembolic events (VTE) are a common complication in cancer patients. Anticoagulant use is the appropriate treatment for acute VTE in cancer, although assumed to be associated with increased risk for bleeding. The population-based relationship of VTE and anticoagulant therapy to survival in glioblastoma patients remains unclear.

METHODS

Frequency, risk factors, treatment and complications of VTE were assessed in a glioblastoma cohort in the Canton of Zurich, Switzerland (2010 to 2014). Survival data were retrospectively analyzed using the log rank test.

RESULTS

248 glioblastoma patients with known isocitrate dehydrogenase (IDH) wildtype status were identified in a 5-year time-frame. Median overall survival (OS) was 12.8 months (95% CI 11.0–14.6), with a median follow up of 60.7 months (95% CI 51.4–70.0). VTE were diagnosed in 35 patients (14.4%; 5 out of 248 patients with no follow-up data on VTE). Median time from diagnosis to VTE was 2.23 months (95% CI 0.6–3.9); 3 patients (8.6%) had a history of VTE. Most patients were on steroids at time of diagnosis of VTE (68.6%), and a Karnofsky Performance Score of less than 70% was documented in 21 patients (60%). Most patients with VTE (88.6%) received therapeutic anticoagulation. Complications, resulting in the cessation of therapeutic anticoagulation, occurred in 11 patients (35.5%), mainly (9 patients, 81.8%) due to intracranial hemorrhage. OS did not differ between patients diagnosed with VTE and those without VTE (p=0.103). Tumor progression was the major cause of death (91.3%); 1.4% of patients died from VTE; 1.9% of the patients suffered unexpected sudden death.

CONCLUSION

Although VTE were identified in 14.4% of glioblastoma patients, VTE were not the major reason for death. These data do not support the implementation of primary thromboprophylaxis in glioblastoma patients. Prospective clinical trials are needed to examine the association of anticoagulant use with survival in glioblastoma patients.
EPID-19. SHARED GENOMIC ARCHITECTURE OF GLIOMA AND NEURO-COGNITIVE AND NEURO-PSYCHIATRIC TRAITS REVEALED BY LD-SCORE REGRESSION
Authors: Walsh Kyle , Ostrom Quinn , Zhang Chenan , Edelson Jacob , Shen Erica , Byun Jinyoung , Han Younghun ,   Collaborators GICC, Amos Christopher , Bondy Melissa
Published: November 2019

BACKGROUND

Genome-wide analyses estimate glioma heritability at 25%, yet known risk loci account for just one-third of this risk and suggest that sporadic glioma is a highly polygenic disease with hitherto unaccounted for genomic architecture. LD-score regression leverages results from genome-wide association studies (GWAS) and known patterns of linkage disequilibrium (LD) to estimate correlation between the genetic architecture of multiple phenotypes. We applied LD-score regression to identify associations with neuro-cognitive and neuro-psychiatric traits not amenable to study in prior glioma case-control analyses.

METHODS

GWAS summary statistics were obtained from the Glioma International Case-Control Consortium (GICC) meta-analysis (Melin, et al. 2017) and for 64 neuro-cognitive and neuro-psychiatric traits primarily from the UK Biobank. Included SNPs had quality scores ≥0.70 and minor allele frequency ≥0.01. Pairwise genetic correlations between traits were estimated using the LDSC package. P-values < 7.8x10-4 (i.e. 0.05/64) were considered significant.

RESULTS

Significant negative correlations were identified between the genetic architectures of glioma and bipolar disorder (Rg=-0.41, P=1.4x10-9) and schizophrenia (Rg=-0.29, P=7.1x10-9), consistent in both GBM and LGG. Significant positive correlations were identified with measures of educational attainment, including age at educational completion (Rg=0.11, P=2.0x10-4), obtaining a college degree (Rg=0.086, P=4.9x10-4), college attendance (Rg=0.086, P=5.9x10-4), and years of education (Rg=0.081, P=7.7x10-4). These associations were notably stronger with LGG. A number of additional nominal associations were observed, including with anorexia (anti-correlated) and performance on a pair-matching cognitive test (positively correlated). Importantly, LD-score regression did not identify an association between glioma risk in GICC data and Townsend deprivation index in UK Biobank data.

CONCLUSIONS

These results implicate a shared genetic basis for glioma and several psychiatric and cognitive traits. Further research is needed to understand these associations and to explore underlying mechanisms, including the mediating effects of neuro-inflammation, developmental differences in neural‒glial cell circuitry, and inter-individual variation in myelination.
EPID-23. PURSUIT OF AN INTERNATIONAL LANGUAGE OF GLIOMA RESEARCH: COMMON DATA ELEMENTS FOR THE LONGITUDINAL STUDY OF ADULT MALIGNANT GLIOMA
Authors: Poisson Laila , Kouwenhoven M C M , Snyder James , Alfaro-Munoz Kristin , Kaur Manpreet , Bates Amanda , Verhaak Roel , Watts Colin , Zadeh Gelareh , Ryan Ormond D , Claus Elizabeth , Khasraw Mustafa
Published: November 2019

As an uncommon cancer, clinical and translational studies of glioma rely on multi-center collaborations, confirmatory studies, and meta-analyses. Unfortunately, interpretation of results across studies is hampered by the absence of uniformly coded clinical data. Common Data Elements (CDE) represent a set of clinical features for which the language has been standardized for consistent data capture across studies, institutions and registries. We constructed CDE for the longitudinal study of adult malignant glioma. To identify the minimum set of CDE needed to describe the clinical course of glioma, we surveyed clinical standards, ongoing trials, published studies, and data repositories for frequently used data elements. We harmonized the identified clinical variables, filled in gaps, and structured them in a modular schema, defining CDE for patient demographics, medical history, diagnosis, surgery, chemotherapy, radiotherapy, other treatments, and outcomes. Multidisciplinary experts from the Glioma Longitudinal AnalySiS (GLASS) consortium, representing clinical, molecular, and data research perspectives, were consulted regarding CDE. The validity and capture feasibility of the CDE were assessed through harmonization across published studies, then validated with single institution retrospective chart abstraction. The refined CDE library is implemented in the Research Electronic Data Capture (REDCap) System, a secure web application for building and managing online surveys and databases. The work was motivated by the GLASS consortium, which supports the aggregation and analysis of complex genetic datasets used to define molecular trajectories for glioma. The goal is that modular REDCap implementation of CDE allows broad adoption in glioma research. To accommodate novel aspects, the CDE sets can be expanded through additional modules. In contrast, for efficient initiation of focused studies, subsets of CDE can be selected. Broad adoption of CDE will improve the ability to compare results and share data between studies, thereby maximizing the value of existing data sources and small patient populations.
EXTH-07. OPTIMIZATION OF TARGETING ELTD1 IN GLIOBLASTOMA USING A MOLECULAR TARGETING APPROACH
Authors: Smith Nataliya , Sauders Debra , Towner Rheal , Zalles Michelle
Published: November 2019

The standard of care for glioblastoma multiform (GBM), an aggressive form of cancer, has not significantly increased the prognosis for patients. ELTD1 (epidermal growth factor, latrophilin, and 7 transmembrane domain containing protein 1), a biomarker for angiogenesis, was found to be highly expressed in human high-grade gliomas. Novel treatments targeting ELTD1 with polyclonal (pAb) and monoclonal (mAb) antibodies were effective as a potential cancer therapy in a G55-xenograft mouse model. While our studies have demonstrated that the blood brain barrier (BBB) was leaky around the tumor region, other studies have shown that the BBB is not equally disrupted in GBM patients, therefore suggesting that the mAb may have difficulty crossing the BBB and infiltrating the tumor due to its size. To overcome these limitations, this study focused on the optimization of targeting ELTD1 by using an optimized svFc antibody fragment derived from our mAb against ELTD1. Immunocompromised mice were intracerebrally injected with human-G55 cells. Morphological MRI was used to monitor and calculate tumor volumes. Treatments using IgG, anti-ELDT1 mAb or fragment upon tumor detection. Vascular perfusion images were obtained to examine vascular alterations. Molecular targeting imaging (mtMRI) was conducted to assess the binding specificity of our antibodies against the tumor region. Targeting ELTD1 with varying antibodies (anti-ELTD1 mAb and scFv fragment) resulted in increased survival and decreased tumor volumes in a G55 xenograft GBM mouse model. Additionally, through the use of mtMRI, we determined altered levels of binding specificity against the tumor region using three different anti-ELTD1 attached probes (monoclonal and scFv fragment antibodies). Our data suggest that the optimization of an anti-ELTD1 therapy could be used to better target angiogenesis in glioblastomas.
EXTH-11. TREATMENT WITH DELTA-24-RGDOX OF SUBCUTANEOUS TUMORS RESULTS IN ABSCOPAL EFFECT ERADICATING INTRACRANIAL MELANOMAS
Authors: Jiang Hong , Ho Shin Dong , Nguyen Teresa , Alonso Marta M , Lang Frederick , Gomez-Manzano Candelaria , Fueyo Juan
Published: November 2019

Immune checkpoint blockade has revolutionized cancer therapy; however the therapeutic benefit is limited to only a subset of patients with immunogenic (“hot”) tumors and is compromised by immune-related adverse events. We have reported the efficacy of oncolytic adenovirus Delta-24-RGDOX (DNX-2440) in syngeneic glioma mouse models. We hypothesized that localized treatment with the virus is effective against disseminated melanomas, including intracranial melanomas. We tested the hypothesis in the subcutaneous (s.c.)/s.c. and s.c./intracranial (i.c.) melanoma models derived from luciferase-expressing B16-Red-FLuc cells in C57BL/6 mice. First, through monitoring tumor growth with bioluminescence imaging, we found that, in both s.c./s.c. and s.c./i.c. models, three injections of Delta-24-RGDOX significantly inhibited the growth of both the virus-injected s.c. tumor and untreated distant s.c. or i.c. tumor, thereby prolonging survival. Next, through cell profiling with flow cytometry, we observed that the virus increased the presence of T cells and effector T cell frequency in the virus-injected tumor and mediated the same changes in T cells from peripheral blood, tumor-draining lymph nodes (TDLNs), spleens, and brain hemispheres with untreated tumor. Moreover, Delta-24-RGDOX decreased the frequency of exhausted T cells and regulatory T cells in the virus-injected and untreated i.c. tumors. Consequently, the virus promoted recruitment and/or in situ expansion of antigen-specific T cells in tumors expressing the target antigen. Therefore, we concluded that local intratumoral injection of Delta-24-RGDOX resulted in systemic immune activity against the disseminated tumors. Furthermore, we speculate that given the immunogenicity, cancer-selectivity and intratumoral administration of the virus, Delta-24-RGDOX is expected to have an improved safety profile when compared to immune checkpoint blockade treatment strategies. This is the first report demonstrating that local administration of oncolytic adenovirus results in eradication of intracranial tumors, suggesting Delta-24-RGDOX could be used to manage brain metastases of melanoma.
EXTH-14. PULSED ELECTRIC FIELDS FOR THE TREATMENT OF BRAIN TUMORS
Authors: Sharabi Shirley , Last David , Daniels Dianne , Cooper Itzik , Bresler Yael , Mardor Yael
Published: November 2019

When high pulsed electric fields (PEFs) are applied to the brain electroporation occurs. Depending on the electric fields strength, irreversible electroporation, inducing necrotic cell death or reversible electroporation, inducing BBB disruption may occur. We have developed a unique minimally-invasive setup for treating brain tumors employing a single insulated intracranial electrode with an exposed tip placed within the tumor and an external surface electrode. This unique setup, termed point-source electroporation, provides intratumoral irreversible-electroporation (inducing necrosis) with surrounding reversible BBB disruption, enabling efficient delivery of systemically administered drugs into the infiltrating zone. Treatment duration is 1–2 min. An efficacy study conducted with 120 glioma-bearing rats resulted in suppressed tumor growth rates in the electroporation+Cisplatin group (1.1±0.1) relative to growth rates in the control group (5.2±1.0), p< 0.047, and in the Cisplatin-only group p< 0.012 (3.92±1.0) (Welch’s F(2,12.73)=10.84; p< 0.002; ω2=0.28). Kaplan-Meir analysis revealed that electroporation+Cisplatin prolonged survival significantly (χ2=7.54; p< 0.006). Immunofluorescence analysis revealed significant infiltration of peripheral macrophages and CD8+ cells in the residual tumor. A finite elements simulation demonstrated the feasibility for obtaining clinically-relevant treatment volumes (~6cm diameter) using a single 3mm (diameter) intracranial catheter. Additionally, we discovered that low PEFs, an order of magnitude lower than electroporation threshold, can also transiently disrupt the BBB by a different mechanism, enabling penetration of both small (Gd/NaF) and large (Evans blue bound to serum albumin) molecules and immune cells, non-invasively. The extent of BBB disruption, measured in mice using delayed-contrast MRI, was found to be linearly dependent both on the electric field strength (r2=0.9,p< 0.03) and on the number of applied pulses (r2=0.94,p< 0.003). These results demonstrate the feasibly of applying combined systemic chemotherapy with point-source electroporation, a minimal-invasive/rapid treatment of PEFs, for obtaining significant antineoplastic effects. Furthermore, low PEFs may be applied non-invasively, rapidly and repeatedly for obtaining reversible BBB disruption.
EXTH-19. IBRUTINIB MODULATES BLOOD-BRAIN BARRIER INTEGRITY TO ENHANCE CHEMOTHERAPY PERMEABILITY
Authors: Meeks Caitlin , Vezina Amelie , Robey Robert , Gottesman Michael , Jackson Sadhana
Published: November 2019

BACKGROUND

The blood-brain barrier (BBB) poses a major treatment challenge for malignant brain tumors. Ibrutinib is an FDA approved Bruton’s tyrosine kinase (BTK) and bone marrow x-linked tyrosine kinase (BMX) inhibitor indicated for the treatment of B-cell lymphomas. BMX is highly expressed in endothelial cells and is suggested to regulate cytoskeletal organization and barrier function in epithelial cells. We hypothesize that inhibition of BMX by ibrutinib in brain endothelial cells will disrupt the integrity of the BBB to increase drug permeability.

METHODS

Protein expression and phosphorylation of BMX was confirmed in immortalized mouse brain endothelial cells (bEnd.3). Endothelial barrier integrity was evaluated with increasing doses of ibrutinib (1–30μM) for 24hrs via the ACEA xCELLigence system (impedance) and the ECIS TEER24 system (resistance). Paracellular permeability of doxorubicin was measured by fluorescent spectrophotometry. Junctional protein expression of VE-Cadherin and F-actin cytoskeletal organization were detected by fluorescent staining. Ibrutinib’s effect on efflux pumps, ABCB1 and ABCG2, was performed by flow cytometry using specific substrates, valspodar and FTC, respectively.

RESULTS

Ibrutinib decreased endothelial cell impedance in a dose-dependent manner over 24hrs, with transient decrease by 46% at 30min with an optimal dose of 1μM, and partial recovery by 4hrs. TEER was decreased by 60% at 3hrs. Ibrutinib enhanced doxorubicin permeability by 30%; attributed to the transient disorganized nature of actin cytoskeletal filaments 2hrs post treatment. No effects on VE-cadherin expression or localization were observed. Ibrutinib successfully inhibited activity of ABCB1 and ABCG2 in a dose-dependent manner.

CONCLUSION

Our results suggest ibrutinib causes transient disruption of the brain endothelial monolayer due to cytoskeletal disorganization and ABC transporter inhibition to enhance permeability of doxorubicin. Further studies using ibrutinib and cytotoxic agents are warranted in glioma bearing animals. We propose that using ibrutinib as an adjunctive therapy may enhance drug delivery to patients with malignant brain tumors.
EXTH-30. PRECEDING p53 STABILIZATION USING DOXORUBICIN AUGMENTS PRIMA-1-MEDIATED p53 REFOLDING AND INCREASED CELLULAR APOPTOSIS: EVALUATION OF A SEQUENTIAL COMBINATION THERAPY AGAINST GLIOBLASTOMA
Authors: Babikir Husam , Afjei Rayhaneh , Paulmurugan Ramasamy , Massoud Tarik
Published: November 2019

INTRODUCTION

Mutant p53 cancer cells are poorly responsive to chemotherapy. A small molecule drug, PRIMA-1, can bind to wildtype and mutant p53 to induce structural conformation that enhances p53 DNA binding. In a quest for new effective combination chemotherapies, we hypothesized that sequential treatment of GBM cells with doxorubicin then PRIMA-1 could stabilize and refold p53 to enhance chemotherapy-induced cellular apoptosis. We evaluated this combination in GBM cells engineered to express different p53 mutants and exhibiting different phenotypes.

METHODS

We constructed split reporter biosensors incorporating different structural mutants of p53 (p53Y220C, p53G245S, and p53R282W) all within p53-null Ln308 GBM cells, to evaluate PRIMA-1-mediated refolding of p53 using bioluminescence imaging. We used these cells, and other GBM cells endogenously dissimilar for p53 phenotypes (U87MG with wt-p53, and Ln229 with mutant p53 [mt-p53P98L/p14ARFdel/p16del]), to investigate the anticancer activity of doxorubicin plus PRIMA-1 by using immunoblot analysis of p53 downstream pathway proteins. We also evaluated treatment by imaging mice implanted with GBMs of different p53 phenotypes.

RESULTS

PRIMA-1 induced reporter complementation at > 80 mM in all GBM cells regardless of p53 status. Doxorubicin stabilized p53 and increased its levels significantly more than in control cells. Significant changes in apoptotic index occurred in GBM cells treated with doxorubicin (1mM) followed by PRIMA-1 (40 mM), compared to cells treated with each drug independently, or with PRIMA-1 followed by doxorubicin. There was upregulation of p53, p21, and Bax, but downregulation of Bcl2 after combination therapy. PRIMA-1 and doxorubicin acted synergistically in GBM cells, but not significantly compared to using doxorubicin followed by PRIMA-1.

CONCLUSION

Our molecular imaging biosensor is useful to detect drug-induced restoration of p53 wildtype conformation. Doxorubicin stabilizes and increases p53 levels in GBM cells for subsequent enhanced PRIMA-1-mediated p53 refolding and increased levels of cellular apoptosis—an effective anti-GBM combination treatment.
EXTH-31. COMBINATION OF TUMOR TREATING FIELDS (TTFIELDS) AND PACLITAXEL PRODUCES ADDITIVE REDUCTIONS IN PROLIFERATION AND CLONOGENICITY IN PATIENT-DERIVED METASTATIC NON-SMALL CELL LUNG CANCER (NSCLC) CELLS
Authors: Michelhaugh Sharon , Mittal Sandeep
Published: November 2019

Clinical trials are underway to test the efficacy of TTFields in patients with progressive NSCLC or NSCLC brain metastases following standard-of-care or radiosurgery, respectively. Our study utilized patient-derived cells isolated from NSCLC brain metastases from a patient previously treated with standard-of-care chemo-radiation prior to progression to brain metastasis. These patient-derived cells underwent TTFields application in vitro with and without paclitaxel to determine if the response to the combination of TTFields with paclitaxel would be different from either treatment alone. Use of patient tissues was approved by the Institutional Review Board. Written informed consent was obtained from the patient, who was 60 years-old and female. She received concurrent carboplatin/paclitaxel and radiotherapy to the upper lobe of her left lung prior to discovery and resection of a solitary brain lesion. Cells isolated from the metastatic brain tumor were cultured for 3 passages prior to plating on coverslips (4×104 each) in DMEM/F12 media with 10% fetal bovine serum. TTFields were applied at ~1.6 V/cm at 150 kHz. Paclitaxel was added to the media to a final concentration of 5 nM. After 14 days, cell lysates were assayed for lactase dehydrogenase (LDH) to represent cell number (n=5) or were harvested and replated in triplicate for the clonogenic assay (n=3). Groups were compared with one-way ANOVA. Mean ± SD of LDH for the control, TTFields-alone, paclitaxel-alone, and the combination were 1.83 ± 0.09, 1.34 ± 0.15, 0.81 ± 0.04, and 0.46 ± 0.21, respectively (ANOVA p< 0.0001). Clonogenic assay counts for the same groups were 26641 ± 4625, 17399 ± 5998, 8697 ± 1617, and 1598 ± 598 (ANOVA p= 0.0003). The additive effects of TTFields and paclitaxel suggest that they target different cell populations within a heterogeneous tumor, and that patients previously treated with standard-of-care may benefit from TTFields therapy.
EXTH-32. DEVELOPMENT OF EPHA3 DIRECTED CHIMERIC ANTIGEN RECEPTOR T CELL THERAPY FOR THE TREATMENT OF GLIOBLASTOMA MULTIFORME
Authors: Ruff Michael , Sakemura Reona , Cox Michelle , Hefazi Torghabeh Mehrdad , Roman Moreno Paulina , Schick Kendall , Sarkaria Jann , Kenderian Saad
Published: November 2019

BACKGROUND

Efficacy of chimeric antigen receptor T cell (CART) therapy remains limited in solid tumors. Given the heterogeneity of surface receptor expression and immunosuppressive stromal microenvironment, strategies to target tumor neovasculature and tumor stromal cells are needed to help overcome CART inhibition by GBM. Eph receptors are the largest family of receptor tyrosine kinases and are integral to cell adhesion, migration, and axon guidance, during development and homeostasis. EphA3 is a receptor tyrosine kinase which is lowly expressed in adult tissues but is highly expressed in tumor neovasculature and tumor stromal cells in GBM and other solid tumors. EphA3 is over-expressed in up to 40% of GBM samples. We aimed to develop CART cells directed against EphA3 to use in targeting tumor neovasculature and tumor stromal cells in GBM.

METHODS

we developed a second generation CD28 co-stimulated CAR construct in a third generation lentivirus backbone to generate EphA3 CART cells using the single chain variable fragment of ifabotuzumab, a monoclonal antibody directed against EphA3. Patient derived GBM xenograft cell lines were used in these experiments.

RESULTS

EphA3 directed CART cells exhibited specific and potent antitumor activity against EphA3+ GBM cell lines with variable transcriptome EphA3 expression indicating its broader applicability in patients with GBM. Killing over 24-hour incubation was significant at low effector: target ratio: 52.5% killing at 1.25:1 against cell lines with 25.05% EphA3 expression and 37.1% killing at 1.25:1and 90% killing at 5:1 ratio against a cell line with 19.28% expression. Conversely, when co-cultured with UTD controls there was significantly lower killing, or growth of tumor cells.

CONCLUSION

We demonstrate for the first time that targeting EphA3 with CART cells is feasible, efficacious and represents a novel therapeutics strategy to target GBM. Data from in vivo and combinatorial CART experiments will be reported at the meeting.
EXTH-39. BENCH TO BEDSIDE NEURO-ONCOLOGY: ADVOCATING FOR A CLINICALLY RELEVANT STRATEGY
Authors: Zammar Samer , Madden Dennis , Schreck Karisa , Berens Michael , Dietrich Jorg , Glantz Michael
Published: November 2019

INTRODUCTION

Therapeutic successes in neuro-oncology have lagged dramatically behind exciting laboratory discoveries, and successful translation of promising laboratory findings into clinical practice is rare. We hypothesize that one important reason for this discordance is the use of very different paradigms for designing laboratory and clinical trials, and that utilizing clinically relevant procedures could improve laboratory study impact.

METHODS

We identified all pre-clinical neuro-oncology therapeutic trials published in four high-impact journals between 11/2018 and 4/2019, and assigned a level of evidence (LOE) to each study using the American Academy of Neurology evidence classification system. We also extracted details about statistical techniques, funding, and institutional setting.

RESULTS

Of the 26 articles identified, 85% had a LOE of IV (highest-I, lowest-IV) and 15% were class III. Factors contributing to the low LOE included lack of randomization (65%) or allocation concealment (100%), absence of masked assessment (96%), and no comparison of treatment and control groups with respect to prognostically relevant characteristics (92%). Effect size and confidence interval reporting, power calculation, correction for multiple hypothesis testing, and multivariate analysis were absent in 92%, 92%, 100%, 88%, and 92% of studies respectively. The “reverse” analysis (starting with successful human trials and analyzing existing pre-clinical support studies) showed significantly more high quality laboratory studies supporting “successful” compared to “unsuccessful” trials (p=0.04).

CONCLUSIONS

When rigorous human clinical trials criteria are applied to therapeutic laboratory studies, laboratory study LOE is uniformly poor. For laboratory research intended to inform clinical trial design and improve clinical outcomes, this situation dooms most basic science research to fail in the clinical arena. The steps required to solve this problem are challenging but addressable, and costs associated with the solution are dwarfed by the expense of early phase human trials which are destine to failure.
EXTH-44. INHIBITION OF MerTK ACTIVATES GLIOBLASTOMA-ASSOCIATED MACROPHAGES AND INDUCES TUMOR CELL DEATH IN GLIOMA MICROENVIRONMENT
Authors: Su Yu-Ting , Butler Madison , Hwang Lee , Maric Dragan , Earp Shelton , Terabe Masaki , Gilbert Mark , Wu Jing
Published: November 2019

BACKGROUND

Glioblastoma-associated macrophages and microglia (GAMs) are the predominant immune cells in the tumor microenvironment. Activation of MerTK, a receptor tyrosine kinase, triggers efferocytosis and polarizes GAMs to an immunosuppressive phenotype, promoting glioma growth. Our previous findings showed that UNC2371, a small-molecule inhibitor of MerTK, induced a less immunosuppressive phenotype of GAMs. Here, we investigate the role of MerTK inhibition on glioblastoma cells in the tumor microenvironment in vitro and in vivo.

METHODS

Cytotoxicity of UNC2371 in glioblastoma cells was determined by cell viability and colony formation assays. The protein expression of MerTK, AKT, and Erk were quantified by Western blotting in UNC2371-treated glioblastoma cells. A syngeneic GL261 mouse orthotopic glioblastoma model was used to evaluate the survival benefit of UNC2371 treatment. Fluorescent multiplex immunohistochemistry (IHC) was used to evaluate the expression of CD206, an anti-inflammatory marker on GAMs in murine brain tumor tissues.

RESULTS

UNC2371 inhibited GBM cell growth with an EC50 < 100 nM in both human U251 and mouse GL261 glioma cells, but not in GAMs. UNC2371-induced cell death and decreased cell proliferation were demonstrated by colony formation assays. UNC2371 decreased protein expression of phosphorylated MerTK, AKT, and Erk, which are essential for cell survival signaling, in U251 and GL261 cells. Furthermore, UNC2371 treatment prolonged survival in the mouse orthotopic GL261 glioblastoma model, suggesting that UNC2371 induces glioma cell death. A decreased of CD206+ GAMs was found in mice glioma tissues by fluorescent multiplex IHC, consistent with our previous findings in the in vitro cell-based assays. These data suggest that in addition to alleviate immunosuppression in the glioma microenvironment, UNC2371 directly inhibits GBM cell growth in vitro and in vivo.

CONCLUSION

Our findings suggest that UNC2371 has a therapeutic benefit via promoting GAM polarization towards proinflammatory status in the glioblastoma microenvironment and unexpectedly, inducing tumor cell death.
EXTH-51. GENETICALLY STABLE POLIOVIRUS VECTOR PLATFORM FOR DIPG IMMUNOTHERAPY
Authors: Gromeier Matthias , Mosaheb Mubeen , Dobrikova Elena , Brown Michael , Bigner Darell , Ashley David
Published: November 2019

Options for the immunotherapy of diffuse intrinsic pontine glioma (DIPG), due to its anatomical location and inherent therapy resistance, are limited. The histone 3.3(K27M) mutation in ~80% of such tumors offers a unique opportunity for immunotherapy intervention, as it defines a high affinity, HLA-A2-restricted tumor neoantigen that spontaneously elicits CD8+ T cell responses in DIPG patients. Immunizing against the H3.3(K27M) signature in the clinic has been challenging, as conventional approaches (i.e. peptide-conjugates administered with adjuvants) lack the costimulatory signals known to drive CD8+ effector T cell responses. Therefore, we built on a viral vector approach for engaging innate immune responses to virus infection specifically in antigen presenting cells. Viruses naturally engage innate immunity, induce antigen presentation, and mediate CD8 T cell priming against foreign antigens. Polioviruses can provide a context optimal for generating antigen-specific CD8 T cells, as they have natural tropism for dendritic cells, preeminent inducers of CD8 T cell immunity; elicit Th1-promoting inflammation; and lack interference with innate or adaptive immunity. However, notorious genetic instability and underlying neuropathogenicity has hampered poliovirus-based vector applications. We devised a strategy based on the polio:rhinovirus chimera PVSRIPO, devoid of viral neuropathogenicity after intracerebral inoculation in human subjects, for stable expression of exogenous antigens. PVSRIPO vectors infect, activate, and induce epitope presentation in DCs in vitro; recruit and activate DCs with Th1-dominant cytokine profiles at the injection site in vivo. They efficiently prime tumor antigen-specific CD8 T cells in vivo, induce CD8 T cell migration to the tumor site, delay tumor growth and enhance survival in syngeneic rodent tumor models. We are preparing a prototype PVSRIPO-derived vector delivering the H3.3(K27M) signature for clinical investigation.
EXTH-55. TEMOZOLOMIDE-RESISTANT GLIOMA CELLS ARE SENSITIVE TO CHLOROETHYLATING NITROSOUREA COMPOUNDS IN COMBINATION WITH ATR INHIBITORS
Authors: Jackson Christopher , Kalathil Aravind , Bindra Ranjit
Published: November 2019

BACKGROUND

Despite decades of research, nearly all patients with glioblastoma (GBM) face recurrent disease. Temozolomide (TMZ), the drug of choice for GBM, methylates guanine bases at the O6 position (O6meG). These lesions are normally repaired by O6meG-methyltransferase (MGMT). When MGMT is deficient (e.g. in the case of promoter hypermethylation), O6meG lesions generate mispairs with thymine and activate the mismatch repair system (MMR), which is thought to be critical for the cytotoxicity of TMZ. Numerous studies have established that acquired MMR deficiency is a common mechanism of TMZ resistance that emerges in recurrent GBM. However, reversion of MGMT-methylation status is not common in recurrent GBM. Recent work from our group demonstrated that TMZ synergizes with ATR inhibitors (ATRi’s) in MGMT-methylated GBM cells. The goal of this project was to identify the specific types of alkylating agents that synergize with ATRi’s in an MGMT-methylated, MMR-deficient molecular context.

RESULTS

We used GBM cell lines U251 and LN229, which are both MGMT-methylated and exquisitely sensitive to TMZ in combination with ATRi at baseline, and created MMR-deficient versions through stable knockdown of MSH2. We determined that MSH2 knockdown conferred remarkable resistance in U251 and LN229 to TMZ treatment in comparison to their respective MMR-proficient counterparts. In addition, we were unable to detect synergy between ATRi’s and TMZ in the setting of MSH2 knockdown. In contrast to TMZ, we found that treatment with chloroethyl nitrosourea (CNU) alkylating agents--including lomustine--with ATRi’s was extremely effective in killing MGMT-methylated, MMR-deficient GBM cells.

CONCLUSION

Here, we report an exquisite synergistic interaction between ATRi’s and CNU agents in MMR-deficient, MGMT-methylated GBM cells. Future work in the lab will examine the interaction of CNU and ATRi’s with radiation therapy (RT). Because ATRi’s are known radiosensitizers, we believe that novel combinations of ATRi’s, lomustine, and re-RT may have promise in recurrent GBM.
EXTH-60. CONVECTION-ENHANCED DELIVERY OF EZH2 INHIBITOR FOR THE TREATMENT OF DIFFUSE INTRINSIC PONTINE GLIOMA
Authors: Sasaki Takahiro , Katagi Hiroaki , Goldman Stewart , Hashizume Rintaro
Published: November 2019

Diffuse intrinsic pontine glioma (DIPG) is a fatal childhood brain tumor and the majority of patients with DIPG die within 2 years after initial diagnosis. Factors that contribute to the dismal prognosis of these patients include the infiltrative nature and anatomic location in an eloquent area of the brain, which prevents total surgical resection and the presence of the blood-brain barrier (BBB), which reduces the distribution of systemically administered agents. Convection-enhanced delivery (CED) is a direct infusion technique to deliver therapeutic agents into a target site in the brain and able to deliver a high concentration drug to the infusion site without systemic toxicities. EZH2, histone methyltransferase of polycomb repressive complex 2, is a potential therapeutic target in DIPG. The study aims to assess the efficacy of EZH2 inhibitor by CED against DIPG xenograft model. The biodistribution of EZH2 inhibitor was evaluated by high-performance liquid chromatography (HPLC). HPLC analysis showed that the concentrationof EZH2 inhibitor in the brainstem tumor was only 3.74% of blood concentration by systemic administration. We treated mice bearing human DIPG xenografts with EZH2-inhibitor using intraperitoneal or CED administration. Intracranial tumor growth was monitored by bioluminescence image and therapeutic response was evaluated by animal survival. CED of EZH2 inhibitor suppressed tumor growth and significantly extended animal survival in compared to intraperitoneal administration of EZH2 inhibitor (P=0.0475). Taken together, our results indicate that CED of EZH2 inhibitor would provide an alternative strategy for bypassing the BBB and increasing efficacy of EZH2 inhibitor for the treatment of DIPG.
GENE-07. INFLUENCE OF EPIGENETIC MODULATION OF THE T-CELL REGULATORS EXPRESSION ON GLIOBLASTOMAS BY HISTONE 3 LYSINE METHYLTRANSFERASE OR DEMETHYLASE ON THE PROGNOSIS OF THE GLIOBLASTOMA PATIENTS
Authors: Kim Mee-Seon , Sam Lee Young , Choel Kim Dae , Zoon Kim Young
Published: November 2019

PURPOSE

The primary aim of this study is to investigate the expression of the T cell stimulators and inhibitors as well as histone modifying enzymes in the glioblastoma cells. Based on the expression of these proteins, authors estimate the prognostic role in glioblastoma patients and also validate the known prognostic factors.

MATERIALS AND METHODS

Using 84 FFPE samples of glioblastoma in the pathologic archives at our institute, immunohistochemical staining for T cell stimulators (CD 27, CD 28, CD 137, OX40, ICOS), inhibitors (CTLA-4, PD-1, PD-L1, TIM3, CD200R), histone 3 lysine methyltransferase (MLL4, RIZ, EZH1, NSD2), and histone 3 lysine demethylase (KDM5c, JMJD1a, UTX, JMJD5).

RESULTS

Median values of the immunohistochemical staining for T cell stimulators and inhibitors were 16.3% of CD27, 10.4% of CD28, 47.5% of CD137, 52.9% of ICOS, 32.2% of OX40, 31.4% of CTLA-4, 7.2% of PD-1, 55.5% of PD-L1, 62.2% of TIM3, and 42.8% of CD200R. In multivariate analysis, increased expression of CD28 (p=0.042), CD137 (p=0.009), EZH1 (p=0.040), and decreased expression of CTLA-4 (p=0.003), PDL-1 (p=0.020) in glioblastoma cells were independently associated with longer OS as well as known prognostic factors such as young age, high KPS, wide extent of resection, PRA class, and methylated MGMT promoter. Interestingly, 42 of 43 samples (97.7%) with decreased PDL1 expression had the increased EZH1 expression, 31 of 33 samples (93.9%) with decreased CTLA4 expression had the increased RIZ expression, 25 of 26 samples (96.2%) with increased CD137 expression had the increased UTX expression, and 36 of 39 samples (92.3%) with increased CD28 expression had the increased JMJD1a expression, respectively.

CONCLUSION

The result of presenting study suggest that the regulators of T cell can be considered as independent prognostic factors in glioblastoma patients and the expression of these regulators can be controlled by unique histone 3 lysine methylation enzymes.
GENE-15. TARGETING OF EPENDYMOMA AS INFORMED BY ONCOGENIC 3D GENOME ORGANIZATION
Authors: Okonechnikov Konstantin , Hübner Jens-Martin , Chapman Owen , Chakraborty Abhijit , Bump Rosalind , Chandran Sahaana , Kraft Katerina , Acuna Hidalgo Rocio , Mundlos Stefan , Coufal Nicole , Levy Michael , Crawford John , Ay Ferhat , Mesirov Jill , Pajtler Kristian , Dixon Jesse , Pfister Stefan , Kool Marcel , Chavez Lukas
Published: November 2019

By profiling enhancers in primary ependymoma tumors, we have recently identified putative oncogenes, molecular targets, and functional pathways. Inhibition of selected targets diminished the proliferation of patient-derived neurospheres and increased survival in mouse models of ependymoma. While enhancers frequently regulate the nearest gene, unambiguous identification of enhancer target genes remains to be a challenge in the absence of chromosome conformation information. Consequently, we have now used HiC to map the 3-dimensional organization of tumor chromatin in the two most common and aggressive ependymoma subgroups: posterior fossa group A (PF-EPN-A) and supratentorial ependymomas with gene fusions involving the NF-κB subunit gene RELA (ST-EPN-RELA). By an integrative analysis of enhancer and gene expression in the context of the newly derived HiC data, we find that a large amount of the previously predicted enhancer target genes can be confirmed by physical interactions. Importantly, we also identify many new putative tumor-dependency genes activated by long-range promoter-enhancer interactions. Complementary to the analysis of gene-enhancer interactions, we have also leveraged the HiC data for resolving structural rearrangements underlying copy number alterations frequently observed in PF-EPN-A tumors. Especially copy number gains of the 1q arm of chromosome 1 are associated with poor survival. Our preliminary results reveal complex structural variants that underlie 1q gains, which lead to inter-chromosomal rearrangements and affect several genes that potentially contribute to poor survival. We now aim to test the relevance of the novel candidate tumor-dependency genes for tumor cell growth and proliferation in patient derived ependymoma models.
GENE-19. TARGETED SEQUENCING PANEL (TODAI ONCOPANEL) FOR VARIOUS TYPES OF BRAIN TUMORS
Authors: Takayanagi Shunsaku , Tanaka Shota , Miyawaki Satoru , Shin Masahiro , Nakatomi Hirofumi , Shinozaki-Ushiku Aya , Oseto Kumiko , Kohsaka Shinji , Oda Katutoshi , Aburatani Hiroyuki , Mano Hiroyuki , Saito Nobuhito
Published: November 2019

BACKGROUND

Todai OncoPanel (TOP) is a targeted sequencing panel newly invented by the University of Tokyo, which allows us to prospectively investigate on genomic abnormalities of multiple cancer-related genes. The objective of this study was to assess its role in molecular diagnosis as well as in patient treatment.

METHODS

Thirteen cases of brain tumors were analyzed: 10 gliomas and glioneural tumors, 2 meningiomas, and 1 intracranial sarcoma. DNA and RNA were obtained from tumor samples; DNA was obtained from peripheral blood as well. The TOP DNA panel analyzed point mutations, insertions, deletions, and copy number variations of 464 cancer-related genes. The TOP RNA panel detected fusions, exon skipping, and expression abnormalities of 463 genes.

RESULTS

In all cases of gliomas, the tumor content was abundantly high and the analysis was performed with sufficient depth. The IDH1/2 mutation status and chromosome 1p/19q status were completely consistent with those obtained by Sanger sequencing and microsatellite analysis. In benign brain tumors, the tumor content tended to be low. The number of gene mutations identified also tended to be low. In a case of glioneuronal tumor, FGFR2 mutation was recognized, but there was no clinical trials of FGFR inhibitors open in Japan yet.

DISCUSSION

TOP is useful as an aid for molecular diagnosis of gliomas. In spite of some targetable genetic abnormalities detected in the tested tumors, its efficacy may be limited by the scant availability of respective molecularly targeted agents.