bluuebunny/crossref_metadata_2025 huggingface dataset:
EPID-22. NEWLY-DIAGNOSED BRAIN TUMORS IN PEDIATRIC PATIENTS: EPIDEMIOLOGY IN THE UNITED STATES
Authors: Torre Matthew , Ascha Mustafa , Harary Maya , Smith Timothy , Aizer Ayal , Ligon Keith , Reardon David , Barnholtz-Sloan Jill , Iorgulescu Bryan
Published: November 2019

INTRODUCTION

Herein we examine the epidemiology across all pediatric intracranial tumors in the U.S.

METHODS

Pediatric patients (< 20yo) presenting between 2010–2015 with an intracranial tumor as the first evidence of cancer were queried from the National Cancer Database, which comprises >70% of cancers newly-diagnosed in the U.S. Tumor types were classified by WHO2016 ICD-O3.

RESULTS

14,952 pediatric patients without a history of cancer presented with intracranial tumors between 2010–2015. Across all ages, these were comprised of 1) 22% diffuse astrocytic and oligodendroglial (n=3,328), 2) 17% sellar region (n=2,530), 3) 16% other astrocytic (n=2,378, 2,131 were pilocytic and pilomyxoid), 4) 13% embryonal (n=1,896; 1,092 were classic histology medulloblastomas), 5) 7% neuronal and mixed neuronal-glial (n=981), 6) 5% ependymal (n=752), 7) 4% GCTs (n=615), 8) 3% mesenchymal non-meningothelial (n=492), 9) 3% nerve sheath (n=428), and 10) ≤2% each of meningioma, choroid plexus, brain metastatic (44% from neuroblastoma), pineal region, hematologic, and other glioma tumors. Embryonal tumors predominated in neonates and infants (0-2yo), diffuse gliomas in childhood (3-11yo), and sellar tumors in adolescents (12-19yo). Females represented 49% of the cases, but sellar tumors predominated (23%, vs. only 11% in males); whereas in males diffuse gliomas predominated (23%; vs. 22% in females) overall and in pediatric patients older than 2yo.

CONCLUSIONS

In U.S. pediatric patients that present with a new intracranial tumor, embryonal tumors and diffuse gliomas predominate in infants ≤2yo, and continue to predominate in male children 3-11yo, whereas female children 3-11yo shifted towards a predominance by diffuse gliomas and other astrocytic tumors (e.g. pilocytic and pilomyxoid). In female adolescents 12-19yo, sellar tumors predominated, followed by diffuse gliomas; whereas in male adolescents diffuse gliomas predominated, followed by other astrocytic tumors and sellar tumors. Our findings demonstrate that newly-diagnosed intracranial masses in pediatric patients significantly vary by both age and sex.
EPID-24. DOES THE LOCATION MATTER? CHARACTERIZATION OF THE ANATOMIC LOCATIONS, MOLECULAR PROFILES, AND CLINICAL FEATURES OF GLIOMAS
Authors: Mackintosh Christopher , Butterfield Richard , Zhang Nan , Bendok Bernard , Zimmerman Richard , Swanson Kristin , Porter Alyx , Mrugala Maciej
Published: November 2019

INTRODUCTION

Locations of gliomas may influence clinical presentations, molecular profiles, treatment options, and prognoses. Using the Mayo Clinic Arizona Cancer Center registry, we analyzed the frequency at which gliomas were identified in different regions of the brain. We evaluated molecular profiles, clinical courses and survival by anatomic location.

METHODS

Registry was queried to include patients with glioma over a 10-year period. Statistical analyses were used to compare demographic, genetic, and clinical characteristics among patients with gliomas in different locations.

RESULTS

182 gliomas were identified. Of the tumors confined to a single lobe, there were 51 frontal (28.0%), 50 temporal (27.5%), 22 parietal (12.1%), and 7 occipital tumors (3.8%) identified. Multifocal disease was noted in 38 patients (20.9%). Tumors affecting temporal lobe were associated with reduced overall survival when compared to all other tumors (11.0 months vs. 13.0 months, log-rank p=0.0068). However, this disparity became insignificant when adjusted for tumor grade, age, and surgical approach [HR(95% CI) 1.26(0.87, 1.82), p=0.212]. Out of 82 cases tested for IDH-1, 10 were mutated (5.5%). IDH-1 mutation was present in 6 frontal, 2 temporal, 1 thalamic, and 1 multifocal tumor. Out of 21 cases tested for 1p19q deletions, 12 were co-deleted, 9 of which were frontal lobe tumors. MGMT methylation was assessed in 45 cases; 7 of 14 frontal tumors and 6 of 13 temporal tumors were methylated. ATRX loss was detected in 2/42 assessed cases.

CONCLUSION

Our results support the hypothesis that the anatomical locations of gliomas influence patients’ clinical courses. Tumors involving the temporal lobe were associated with poorer survival, though this association appeared to be driven by these patients’ more aggressive tumor profiles and higher risk baseline demographics. Molecular analysis was limited by low prevalence of genetic testing in the study sample, highlighting the importance of capturing this information for all gliomas.
EPID-27. OCCURRENCE OF SYSTEMIC CANCER IN PATIENTS WITH ASTROCYTOMA: POPULATION CHARACTERIZATION AND COMPLICATIONS
Authors: Horta Erika , Snyder James , Walbert Tobias
Published: November 2019

It is unclear how the diagnosis of a second cancer influences the treatment and complications of patients with astrocytoma. A chart review of patients with astrocytoma and a second systemic cancer was performed to understand the possible complications that a systemic cancer diagnosis might bring to the treatment of the patient. Inclusion criteria was the histological diagnosis of diffuse or anaplastic astrocytoma and another non-skin systemic cancer. Exclusion criteria was the diagnosis of any genetic syndrome that predisposes tumorigenesis. A total of 17 patients were identified. The most common systemic cancer was thyroid (22) followed by colon and breast cancer (each one 17%). Men were 59% of the patients (p= 0.38), but older (60 +14 years, p=0.003) when compared to CBTRUS data. Systemic cancer was diagnosed before astrocytoma in 61% of the cases. Age at the diagnosis of systemic cancer was 48 +14 years. Only 9% of the patients who had systemic cancer before astrocytomas survived 5 years, what is less than expected when compared with literature, (p=0.02). Those also survived less than the patients that had systemic cancer after the diagnosis of astrocytomas (8.1+6.4 years). Thromboembolism was seen in 12.5% (p=0.8), always after the astrocytoma diagnosis. Thrombocytopenia was not related to prior chemotherapy. In patients with systemic cancer diagnosed while on treatment for astrocytoma, a delay or shortened course of the treatment was seen in rare cases, and one patient had their course of treatment for astrocytoma shortened. The conclusion of this chart review of patients with the diagnosis of astrocytoma and a systemic cancer identifies that this population is older than expected and the diagnosis of systemic cancer before astrocytoma might predict a shorter survival.
EPID-28. WHAT DO PATTERNS OF “UNCLASSIFIED” BRAIN TUMORS TELL US ABOUT INCIDENCE RATES OF NON-MALIGNANT BRAIN TUMORS IN CANADA?
Authors: Smith Trenton , Walker Emily , Yuan Yan , Davis Faith , Megyesi Joseph
Published: November 2019

BACKGROUND

Patients with non-malignant brain tumors (NMBT) can experience significant morbidity and mortality; the degree of which varies by histological subtype. A recent report on all primary brain tumors in Alberta (AB), British Columbia (BC), Manitoba (MB) and Ontario (ON) showed 19.1% of NMBT were categorized as ‘unclassified’. Missing data on histological subtypes encumbers efforts to understand the burden of disease associated with NMBT. The purpose of this analysis was to examine the distribution of unclassified tumors across participating provinces to identify targets for improved surveillance.

METHODS

Data were provided from cancer registries in AB, BC,MB, and ON. Age Standardized Incidence Rates (ASIR) and frequencies were estimated using SAS 9.4. Given data from the United States (U.S) is accurate and the population is comparable, ASIR of NMBT in the U.S were used as expected values in this analysis. The 2011 Canadian Population and the 2000 US population were used for standardization to compare within Canada and to U.S data respectively.

RESULTS

The ASIR of total NMBT and was highest in ON, relative to other participating provinces and similar to that of the U.S (15.25 and 15.91 cases/100,000 person-years, respectively). However, ON had an ASIR about 10 times higher than other provinces for unclassified tumors (ON:6.3 cases/100,000 person-years; BC: 0.4 cases/100,000 person-years; AB:0.3 cases/100,000 person-years; and MB:0.6 cases/100,000 person-years). When unclassified tumors were excluded from the analysis, the ASIR of NMBT was similar across participating provinces.

CONCLUSIONS

Findings from this analysis indicate that the Ontario provincial cancer registry has complete data on total NMBT cases. However, the high ASIR of unclassified cases in the NMBT category indicates that quality control measures could be improved. Further examination of the unclassified cases in ON could be used to improve the accuracy of the ON cancer registry and the completeness of other province’s registries.
EPID-34. GEODEMOGRAPHIC CLASSIFICATION OF GLIOBLASTOMA RISK IN A RURAL HOSPITAL SYSTEM: RELATIONSHIP TO TUMOR INCIDENCE AND OVERALL SURVIVAL
Authors: Haadi Ali , Kosman Justin , Bross Shane , Manikowski Jesse , Hinger Bradley , Conger Andrew , Vadakara Joseph , Tosha Gatson Na
Published: November 2019

In 2019, a projected 86,000 persons in the US will be diagnosed with a primary brain tumor, with an estimated prevalence of 700,000. Glioblastoma (GBM) is the deadliest and most common of these tumors in adults with an overall survival ~15 months. Exposure to ionizing radiation is the single known environmental risk factor for GBM. Most research in the field is directed at treatment and tumor biology/classification. There is growing interest in geodemographics, disease prevention, and measuring quality-survival in GBM. We evaluated 622 GBM patients (2006 to 2018) in Northeastern/Northcentral Pennsylvania treated at one of the nation’s largest rural hospital systems. Each patient was geocoded (plotted longitude/latitude) address at time of diagnosis and we used medical records, projected 2015 Census, and Environmental Protection Agency data to develop risk maps. Preliminary evaluation of overall survival (OS) and incidence related to distance from hospital, age, sex, level of education, insurance, income, and income disparity (Gini coefficient measure of income inequality) was completed. Interestingly, all significant clusters of high GBM incidence lay along water-ways or overlapped with high coal mine reprocessing. Contrary to recent studies, there was no significant sex or distance (0mi to 150mi) impact on survival. However, each age-decile increase resulted in an average 9mo decrease in OS (37mo[< 40yo], 26mo [41-50yo], 17mo [51-60yo], 12mo [61-70yo], and 3mo [>71yo]). Counties with the lowest OS shared geodemographic characteristics such as fewer insured and lower incomes (low income inequality), and counties with more college educated persons had longer survival. Counties with higher GBM incidences had better insured percentages, lower incomes (high income inequality), and large polarity between high school uneducated and college educated persons. Rural populations potentially demonstrate unique geodemographic characteristics that might better predict disease outcomes. Studies in this area could influence improvements in public policy and prevention-focused health literacy opportunities.
EXTH-02. THE BLOOD BRAIN BARRIER (BBB) PERMEABILITY IS ALTERED BY TUMOR TREATING FIELDS (TTFIELDS) IN VIVO
Authors: Schulz Ellina , Kessler Almuth F , Salvador Ellaine , Domröse Dominik , Burek Malgorzata , Tempel Brami Catherine , Voloshin Sela Tali , Giladi Moshe , Ernestus Ralf-Ingo , Löhr Mario , Förster Carola , Hagemann Carsten
Published: November 2019

OBJECTIVE

For glioblastoma patients Tumor Treating Fields (TTFields) have been established as adjuvant therapy. The blood brain barrier (BBB) tightly controls the influx of the majority of compounds from blood to brain. Therefore, the BBB may block delivery of drugs for treatment of brain tumors. Here, the influence of TTFields on BBB permeability was assessed in vivo.

METHODS

Rats were treated with 100 kHz TTFields for 72 h and thereupon i.v. injected with Evan’s Blue (EB) which directly binds to Albumin. To evaluate effects on BBB, EB was extracted after brain homogenization and quantified. In addition, cryosections of rat brains were prepared following TTFields application. The sections were stained for tight junction proteins Claudin-5 and Occludin and for immunoglobulin G (IgG) to assess vessel structure. Furthermore, serial dynamic contrast-enhanced DCE-MRI with Gadolinium contrast agent was performed before and after TTFields application.

RESULTS

TTFields application significantly increased the EB accumulation in the rat brain. In TTFields-treated rats, the vessel structure became diffuse compared to control cryosections of rat brains; Claudin 5 and Occludin were delocalized and IgG was found throughout the brain tissue. Serial DCE-MRI demonstrated significantly increased accumulation of Gadolinium in the brain, observed directly after 72 h of TTFields application. The effect of TTFields on the BBB disappeared 96 h after end of treatment and no difference in contrast enhancement between controls and TTFields treated animals was detectable.

CONCLUSION

By altering BBB integrity and permeability, application of TTFields at 100 kHz may have the potential to deliver drugs to the brain, which are unable to cross the BBB. Utilizing TTFields to open the BBB and its subsequent recovery could be a clinical approach of drug delivery for treatment of brain tumors and other diseases of the central nervous system. These results will be further validated in clinical Trials.
EXTH-08. REPLACEMENT OF MICROGLIA BY BRAIN-ENGRAFTED MACROPHAGES PREVENTS MEMORY DEFICITS AFTER THERAPEUTIC WHOLE-BRAIN IRRADIATION
Authors: Feng Xi , Gupta Sonali , Chen David , Boosalis Zoe , Liu Sharon , Gupta Nalin , Rosi Susanna
Published: November 2019

Microglia have a distinct origin compared to blood circulating myeloid cells. Under normal physiological conditions, microglia are maintained by self-renewal, independent of hematopoietic progenitors. Following genetic or pharmacologic depletion, newborn microglia derive from the local residual pool and quickly repopulate the entire brain. The depletion of brain resident microglia during therapeutic whole-brain irradiation fully prevents irradiation-induced synaptic loss and recognition memory deficits but the mechanisms driving these protective effects are unknown. Here, we demonstrate that after CSF-1R inhibitor-mediated microglia depletion and therapeutic whole-brain irradiation, circulating monocytes engraft into the brain and replace the microglia pool. These monocyte-derived brain-engrafted macrophages have reduced phagocytic activity compared to microglia from irradiated brains, but similar to locally repopulated microglia without brain irradiation. Transcriptome comparisons reveal that brain-engrafted macrophages have both monocyte and embryonic microglia signatures. These results suggest that monocyte-derived brain-engrafted macrophages represent a novel therapeutic avenue for the treatment of brain radiotherapy-induced cognitive deficits.
EXTH-09. FIRST-IN-HUMAN DOSING CONSIDERATIONS OF A BISPECIFIC ANTIBODY FOR TREATING GLIOBLASTOMA
Authors: Schaller Teilo , Foster Matthew , Spasojevic Ivan , Gedeon Patrick , Sanchez-Perez Luis , Sampson John
Published: November 2019

Current therapy for glioblastoma (GBM) is incapacitating and limited by non-specific toxicity to the surrounding brain. We have developed an immunotherapeutic approach that selectively targets GBM by redirecting the patients’ own T cells towards the tumor in an antigen-specific manner using a bispecific antibody. Our novel bispecific antibody (“BRITE”) binds GBM-specific surface marker EGFRvIII and the CD3 receptor on T cells, resulting in crosslinking and tumor-specific cell lysis. We previously showed in patient-derived and syngeneic murine glioma models, that treatment with BRITE leads to long-term survival in mice with glioblastoma. A pharmacokinetic analysis in a CD3 humanized mouse revealed that BRITE in plasma and whole blood has an initial half-life of ~8 minutes and a terminal half-life of ~2.5 hours. Given our preclinical success, we have initiated clinical trial-enabling studies, including studies of BRITE toxicology and GMP manufacturing of drug product. A crucial consideration for our proposed Phase 1 dose escalation trial is the starting dose in humans. To this end, we utilized the FDA-recommended minimum anticipated biological effect level (MABEL) of BRITE – a holistic approach that considers all available in vitro and in vivo data – to calculate the first-in-human starting dose of BRITE.
EXTH-16. HUMAN PLACENTAL HEMATOPOIETIC STEM CELL DERIVED NATURAL KILLER CELLS FOR GLIOBLASTOMA IMMUNOTHERAPY
Authors: He Shuyang , Gleason Joseph , Habboubi Nassir , Hariri Robert , Zhang Xiaokui
Published: November 2019

Taniraleucel (CYNK-001) is an allogeneic, off-the-shelf cell therapy enriched for CD56+/CD3- NK cells expanded from placental CD34+ cells. CYNK-001 exhibits in vitro cytotoxicity against various cancer cell types, including glioblastoma multiforme (GBM), and secretes cytokines during co-culture with cancer cells. To evaluate in vivo anti-GBM activity, safety and persistence of CYNK-001, we conducted two studies in the non-obese diabetic (NOD)-scid IL2Rgammanull (NSG) immune deficient mouse models. First, CYNK-001 in vivo anti-GBM activity was assessed in a U-87MG orthotopic NSG mouse model. Luciferase-expressing U-87MG cells were stereotactically injected into the cranium of NSG mice at Day 0. Repeated dosing of 0.5x106 CYNK-001 cells at Day 14 and Day 25 by intracranial (IC) injection showed a statistically significant reduction of Bioluminescence Imaging (BLI) compared to the PBS control. Furthermore, intravenous (IV) and intracerebroventricular (ICV) routes of administration were evaluated compared to IC. CYNK-001 administered with IC resulted in a greater reduction of BLI than IV and ICV. Second, a single-dose toxicity study was conducted in naïve NSG mice to assess the safety and persistence of CYNK-001 following an IC injection. IC administration of 1×106 CYNK-001 was well tolerated, and no adverse clinical symptoms were observed. Quantitative polymerase chain reaction (qPCR) analysis for the human telomerase reverse transcriptase (hTERT) gene revealed that CYNK-001 persisted in the brain up to seven days. Our studies demonstrated that CYNK-001with IC administration appears safe and well tolerated in naïve as well as U-87MG tumor bearing NSG mice. Furthermore, CYNK-001 anti-tumor activity was exhibited in a GBM orthotopic NSG mouse model. Taken together, our data support a safety and efficacy evaluation of CYNK-001 in patients with GBM. A Phase 1 study in adult patients with recurrent/refractory GBM is planned to start this year evaluating the safety and efficacy of CYNK-001 with both IV and IC administrations.
EXTH-20. HYPERPOLARIZED [2-13C] PYRUVATE TO [5-13C] GLUTAMATE AS BIOMARKERS OF IDH1 MUTANT GLIOMA RESPONSE TO TEMOZOLOMIDE THERAPY
Authors: Subramani Elavarasan , Najac Chloe , Batsios Georgios , Viswanath Pavithra , Radoul Marina , Marie Gillespie Anne , Pieper Russell O , Ronen Sabrina
Published: November 2019

Low-grade gliomas, driven by mutations in the cytosolic isocitrate dehydrogenase 1 (IDH1) gene, are less aggressive than primary glioblastoma, but nonetheless always recur and ultimately lead to patient death. The treatment of IDH1 mutant patients with Temozolomide (TMZ) improves survival, but there remains a need for complementary imaging methods to assess response to therapy at an early time point. The goal of this study was, therefore, to determine the value of magnetic resonance spectroscopy (MRS)-based metabolic imaging biomarkers for detection of response to treatment. To this end we investigated NHA and U87 cells expressing IDH1 R132H mutant gene (NHAIDHmut and U87IDHmut) and first used 1H MRS combined with chemometrics to examined the metabolic alterations that occurred following treatment with the IC50 value of TMZ. We observed a significant increase in 2-hydroxyglutarate (2-HG), glutamate, and glutamine, and metabolic pathway analysis showed tricarboxylic acid (TCA) cycle and pyruvate metabolism to be significantly altered pathways following TMZ treatment compared to DMSO control. To confirm changes in TCA cycle flux and to assess the metabolic pathways contributing to the increase in 2-HG and glutamate/glutamine, cells were then labelled with [1-13C] glucose and [3-13C] glutamine. Our data indicated that both glucose flux via the TCA to glutamate and 2HG, and the contribution of glutamine to glutamate and 2HG were increased following TMZ treatment. Finally, we used hyperpolarized 13C-MRS to dynamically probe the metabolism of hyperpolarized [2-13C] pyruvate and its conversion to hyperpolarized [5-13C] glutamate via the TCA cycle. Consistent with our previous findings, we observed that hyperpolarized [5-13C] glutamate synthesis was significantly higher in TMZ-treated cells compared to controls. Collectively, our findings identify 1H MRS-detectable elevation of 2-HG and glutamate/glutamine as well as hyperpolarized 13C-MRS-detectable [5-13C] glutamate production from [2-13C] pyruvate as potentially translatable metabolic biomarkers of response to TMZ therapy in mutant IDH1 glioma.
EXTH-25. A MECHANICALLY-ENGINEERED SPRAY TO INCREASE BRAIN PENETRATION OF CHEMOTHERAPEUTIC NANOPARTICLES IN THE TREATMENT OF HIGH GRADE GLIOMAS
Authors: McCrorie Phoebe , Taresco Vincenzo , Ritchie Alison , Clarke Phillip , Scurr David , Marlow Maria , Rahman Ruman
Published: November 2019

Design and implementation of innovative local drug delivery systems (DDS) may overcome current limitations in GBM treatment, such as the lack of therapeutic drug concentrations reaching residual GBM cells following surgery. Here we describe a novel DDS which utilises a bespoke mechanically engineered spray device, designed for safe surgical use, to deliver a mucoadhesive hydrogel containing chemotherapeutic nanoparticles (NPs) into the tumour resection margins. The overall aim is to spray a NP and polymer solution onto the resection cavity and potentially increase penetration of anti-cancer drugs within the 2 cm reoccurrence zone beyond the infiltrative margin. The mucoadhesive gel of choice, pectin, is currently used in other in vivo applications; however we have repurposed this for the brain. Pectin is biocompatible with GBM and human astrocyte cells in vitro and showed neither toxicity nor inflammation for up to 2 weeks upon orthotopic brain injection. Pectin is biodegradable in artificial CSF and is capable of being sprayed from the engineered device. A panel of polymeric, oil-based and polymer-coated NPs have been developed and optimised to maximise drug encapsulation of etoposide and olaparib as proof-of-concept for combination drug delivery. Etoposide/olaparib were chosen due to cytotoxicity from 5 GBM cell lines, including primary lines isolated from the invasive tumour margin (Mean IC50 of 1.1 µM and 8.3 µM respectively). The optimal NP/drug formulation (based on drug encapsulation, spray capability and bio-adhesiveness) will ultimately be assessed for tolerability and efficacy using orthotopic allograft and xenograft high-grade glioma models, including measurement of penetration of drug/nanoparticle in ex vivo murine and porcine brain using novel hybrid time-of-flight/Orbitrap TM secondary ion mass spectrometer (orbiSIMS) technology.
EXTH-28. TARGETED POLYGIONS ENGINEERED WITH SURFACE miRNAs FOR COMBINED MULTIMODALITY IMAGING AND ENHANCEMENT OF TEMOZOLOMIDE TREATMENT: A NOVEL INTRANASALLY-DELIVERED THERANOSTIC STRATEGY AGAINST GLIOBLASTOMA
Authors: Sukumar Uday , Afjei Rayhaneh , Massoud Tarik , Paulmurugan Ramasamy
Published: November 2019

INTRODUCTION

We investigate intranasal targeted delivery of theranostic Polyfunctional Gold Iron Oxide Nanoparticles (PolyGIONs) surface loaded with therapeutic microRNAs to allow sensitizing of GBM cells to systemic temozolomide (TMZ), as well as multimodality molecular, anatomic and microscopic imaging.

METHODS

We synthesized PolyGIONs coated with b-cyclodextrin-chitosan hybrid polymer, loaded with miR-100 and antimiR-21, and decorated with PEG-T7 peptide. We characterized the PolyGIONs for microRNA loading efficiency, particle size, PDI, and charge using dynamic light scattering analysis; and for size and polymer functionalization using TEM. We studied PolyGIONs in GBM cells (U87MG and U373MG), and in nude mice orthotopically bearing GBMs after intranasal delivery, in combination with systemic TMZ. We also imaged mice bearing tumors using CT, MRI, bioluminescence, fluorescence, and by ex vivo microscopy.

RESULTS

The optimized PolyGIONs delivered to GBM cells showed efficient cellular uptake when imaged for intracellular Cy5-microRNAs, and therapeutic effects when investigated using MTT and FACS analysis. In a co-culture model of BMVEC (brain microvascular endothelial cells) and U87MG cells, we observed significant upregulation of p53 protein expression in U87MG cells after PolyGIONs treatment. The enhanced therapeutic potential of TMZ upon miR-100 and antimiR-21 sensitization by PolyGIONs was validated in both U87MG and U373MG cells. Mouse tumors revealed specific accumulation of PolyGIONs, and the highest upregulation of p53 expression within tumors of longest surviving mice, when co-treated with TMZ. Moreover, in vivo selective accumulation of PolyGIONs conjugated to T7 peptide within GBMs acted as a useful MRI and CT dual contrast agent, providing longitudinal multimodality imaging of PolyGION effects on GBMs.

CONCLUSION

Our preliminary results indicate the potential for targeting the p53 pathway in GBM using therapeutic miR-100 and antimiR-21 via intranasally delivered PolyGIONs, to enhance the chemotherapeutic effects of systemically delivered TMZ. PolyGIONs also allow simultaneous multimodality imaging to track cancer growth in response to treatment.
EXTH-33. RECEPTOR PHARMACOLOGY OF ONC201: THE FIRST BITOPIC DRD2 ANTAGONIST FOR CLINICAL NEURO-ONCOLOGY
Authors: Benjamin Free R , Cuoco Caroline , Prabhu Varun , Willette Blair , Day Marilyn , Anantharaman Lakshmi , Sulli Chidananda , Davidson Edgar , Deacon Sean , Rucker Joseph , Charter Neil , Doranz Benjamin , Oster Wolfgang , Stogniew Martin , Robert Lane J , Sibley David , Allen Joshua
Published: November 2019

ONC201 has exhibited durable tumor regressions in midline high grade glioma patients. G protein-coupled receptor (GPCR) dopamine receptor D2 (DRD2) is overexpressed in high grade gliomas, controls several oncogenic mechanisms, and its antagonism causes tumor cell apoptosis. Using bioinformatic and GPCR screens, we previously demonstrated selective DRD2/3 antagonism by ONC201 at therapeutic concentrations that translates into a wide therapeutic window, unlike antipsychotics that also target other dopamine receptors and GPCRs (Prabhu et al. CCR 2019 and Madhukar et al. Nat Comm in press). Here, we identify hallmarks of non-competitive DRD2 antagonism by ONC201 in β-arrestin, cAMP and radioligand competition assays. ONC201 caused both a shift in the IC50 and repression of Emax in the dopamine-dose-response curves for DRD2. Schild analysis and fitting these data to an operational model of allostery were consistent with non-competitive antagonism. Alanine scanning mutagenesis of DRD2 identified 6 orthosteric and allosteric residues that are critical for ONC201-mediated antagonism. The residues identified were predominantly conserved in DRD2/3 and were not relevant for antagonism by antipsychotics further explaining the unique selectivity of ONC201. Molecular docking revealed orthosteric interactions at TM-II and an extended binding pocket into an allosteric site. Other critical residues were clustered at an allosteric area at the interface of TM-IV and –V that has been shown to mediate the DRD2 homodimer interface. Point mutations at either site decreased the affinity of ONC201 in competition assays with radiolabeled methyl-spiperone, suggesting cooperativity between these topographically distinct sites. In summary, ONC201 causes a mixed non-competitive and competitive antagonism of DRD2 consistent with a bitopic mechanism of action that may explain its unique selectivity, safety, and anti-cancer activity in clinical trials as the first compound to target this receptor for clinical neuro-oncology. Non-competitive DRD2 antagonism may be critical for ONC201 anti-tumor efficacy in dopamine-rich microenvironments such as midline gliomas.
EXTH-35. LASER INTERSTITIAL THERMAL THERAPY INCREASES BLOOD-BRAIN BARRIER AND BLOOD-TUMOR BARRIER PERMEABILITY IN A MOUSE MODEL OF GLIOBLASTOMA
Authors: Paturu Mounica , Salehi Afshin , Caine Matthew , Mahlokozera Tatenda , Yano Hiroko , Leuthardt Eric , Klein Robyn , Schmidt Robert , Kim Albert
Published: November 2019

INTRODUCTION

A central challenge in glioblastoma treatment is the presence of the blood-brain barrier (BBB) and blood-tumor barrier (BTB), which prevent access of drugs to the brain and tumor respectively. Recent evidence in patients suggests laser interstitial thermal therapy (LITT), used clinically for tumor ablation, locally disrupts BBB integrity, potentially creating a therapeutic window to deliver otherwise brain-impermeant agents.

METHODS

A mouse model for LITT, established using a Nd-YAG laser coupled to a 600 mm fiber optic and thermocouple probe, was inserted via burrhole to target the somatosensory cortex. Syngeneic GL261 tumor cells were stereotactically implanted prior to LITT. BBB and BTB permeability were assessed through measurement of fluorescein and doxorubicin after IV injection. Permeability of IV dextran (10 and 70 kDa) and human IgG was monitored by immunohistochemistry (IHC) analysis. Mechanisms of BBB breakdown in vivo were explored utilizing electron microscopy and IHC.

RESULTS

By fluorescein assay, LITT-induced BBB and BTB permeability began one day post-treatment and was sustained for at least 2 weeks. Additionally, both normal brain and brain tumors demonstrated an increase in Dextran 10 kDa, Dextran 70 kDa, and human IgG extravasation after IV injection in vivo. Mechanistically, we provide evidence that LITT triggers both a decrease in tight junction integrity and an increase in brain endothelial cell transcytosis. As proof-of-concept that LITT can enhance tumor delivery of systemic drugs, LITT increased IV doxorubicin permeability in brain in vivo. Moreover, LITT plus doxorubicin significantly increased survival in brain tumor-bearing mice compared to doxorubicin or LITT alone.

CONCLUSIONS

Our data suggest that LITT increases BBB and BTB permeability over a defined time window to large molecular weight agents, including antibodies, through multiple cellular mechanisms. Our preclinical results with LITT plus doxorubicin, which mirror a current clinical trial, indicate LITT can enhance the efficacy of systemically delivered drugs.
EXTH-40. SPECIFIC DENDRIMER-MEDIATED DELIVERY OF IMMUNOTHERAPY BLZ945 TO TUMOR-ASSOCIATED MACROPHAGES IMPROVES THERAPEUTIC EFFICACY IN GLIOBLASTOMA
Authors: Liaw Kevin , Reddy Rajsekhar , Sharma Rishi , Salazar Sebastian , Jinemez Ambar , Kannan Sujatha , Kannan Rangaramanujam
Published: November 2019

Patients with glioblastoma have failed to see improved outcomes despite the discovery of powerful anti-cancer drugs because such therapies do not adequately cross the blood-brain barrier and penetrate into solid tumors to access pathological cells. In addition to these delivery challenges, tumors polarize host macrophages into tumor-associated macrophages (TAMs), which suppress the tumor-killing response and create a growth-conducive immune environment for cancer cells. As a result, TAMs are promising therapeutic targets but translational efforts targeting them have largely failed due to low response rates and high systemic toxicities. Therefore, a vehicle that carries immunotherapies into the brain, deep into solid tumors, and specifically to TAMs while remaining inactive in the body provides a promising clinical strategy. Here, we present hydroxyl-terminated polyamidoamine (PAMAM) dendrimers as novel targeted drug delivery systems to overcome these delivery challenges in the GL261 mouse model of glioblastoma. Upon systemic administration, these dendrimers, without any targeting ligands, are able to cross the blood-brain barrier, distribute uniformly throughout the solid glioblastoma tumor, and localize specifically within TAMs. Dendrimers display high tumor specificity (>5-fold compared to the contralateral hemisphere) and minimal systemic accumulation (< 5% initial dose remaining in livers or kidneys after 24 hours). We then conjugated BLZ945, a potent immunotherapy that prevents tumors from recruiting TAMs, to the dendrimer via pH-sensitive linkers for triggered intratumoral and intracellular release. We find that a single systemic dose of dendrimer-delivered BLZ945 halfway through disease progression prolongs survival by >30% compared to free BLZ945 and untreated cohorts. These survival benefits were accompanied by amelioration of disease progression and improved motor function. Finally, we demonstrate that repeat dosing of dendrimer-delivery BLZ945 in combination with current standard of care temozolomide provides robust, synergistic improvements to survival and disease severity. These studies validate the potential of dendrimers for localized immune manipulation in glioblastoma.
EXTH-47. THERAPEUTIC REVERSAL OF PRENATAL PONTINE ID1 SIGNALING IN DIPG
Authors: Harris Micah , Yadav Vivekanand , Stallard Stefanie , Woo Rinette , Siddaway Robert , Qin Tingting , Mullan Brendan , Miklja Zachary , Siada Ruby , Ravindran Ramya , Cao Xuhong , Pasternak Amy , Castro Maria , Lowenstein Pedro , Mody Rajen , Chinnaiyan Arul , Hawkins Cynthia , McAllister Sean , Desprez Pierre , Venneti Sriram , Koschmann Carl
Published: November 2019

Diffuse intrinsic pontine gliomas (DIPGs) are lethal brain tumors with no effective therapies other than radiation. Inhibitor of DNA binding (ID) proteins are key regulators of tissue and lineage-specific gene differentiation during embryogenesis. Previous work has shown that H3F3A and ACVR1 mutations increase ID1 expression in cultured astrocytes, but this has not been validated in human DIPG, nor has the regulation and targetability of ID1 been explored in DIPG. Analysis of multi-focal post-mortem tumor and normal brain tissue (n=52) as well as multiple human datasets revealed ID1 to be elevated in DIPG. Elevated ID1 was found to correlate with reduced survival in DIPG. In a multi-focal autopsy DIPG case, we found ID1 expression to be heterogeneous and to correlate with tumor invasion. Chromatin immunoprecipitation-qPCR (ChIP-qPCR) was used to quantify H3K27ac and H3K27me3 at ID1 gene regulatory regions (promoters/enhancers) in multi-focal post-mortem tissue. The ID1 loci was found to be epigenetically poised for up-regulation (elevated H3K27ac and low H3K27me3) in DIPG tissue, regardless of H3 or ACVR1 mutation status, compared to normal brain. Analysis of publically-available ISH and ChIP-sequencing data revealed elevated ID1 expression and ID1-enhancer H3K27ac in prenatal mouse hindbrain compared to prenatal forebrain, prenatal midbrain, and all postnatal brain regions. ID1 shRNA-mediated knockdown of primary human H3K27M DIPG cells (DIPG007) resulted in significantly reduced invasion and migration. As cannabidiol (CBD) has successfully been used to therapeutically target ID1 in pre-clinical models of adult human cancers, we treated DIPG007 cells with CBD and found reduced viability at clinically relevant dosing (IC50=2.4 uM) with dose-dependent reduction in ID1 protein. ID1 knockdown and CBD treatment studies in murine models of DIPG are ongoing. These findings indicate that a multifactorial (genetic and regionally-based) epigenetic upregulation of ID1 drives DIPG invasiveness and is targetable with CBD.
EXTH-48. GALECTIN-1 INHIBITION SENSITIZES RADIATION TREATMENT IN A PRE-CLINICAL MODEL OF GLIOBLASTOMA
Authors: Henderson Fraser , Das Arabinda , Kanginakudru Indira , McDonald Daniel G , Kosnik Infinger Libby , Vandergrift III William , Varma Abhay , Vanek Kenneth N , Lindhorst Scott , Patel Sunil , Cachia David
Published: November 2019

Radioresistance remains a major clinical challenge in glioblastoma (GB) therapy. However, the mechanism for the development of radioresistance in GB is unclear. Mounting evidence suggests that Galectin-1 (Gal1: a carbohydrate-binding protein galectin-1) contributes to the radioresistance of GB tumors. Recently, several Gal1-targeting compounds have emerged. OTX008 is a calixarene derivative designed to bind the Gal1 amphipathic β-sheet conformation. Our study aimed to reduce galectin-1 expression using OTX008 in a human GB pre-clinical model. For these studies an in vivo GL261 murine models of GB were utilized to assess efficacy of treatment with radiation plus OTX008. Our results demonstrated that inhibition of Gal-1 with OTX008 plus radiation showed significantly decrease in GB growth rate and improved survival in in vivo. OTX008 treatment plus radiation was associated with downregulation of Gal1 and Ki67 in treated tumors, as well as decreased microvessel density and VEGFR2 expression. Finally, combination studies showed OTX008 synergy with radiation therapies, principally when OTX008 was administered first. This study provides insights of Gal-1inhibitory effects of OTX008 and its enhancement of the efficacy of radiotherapy in mouse models of GB suggest that further studies are warranted.
EXTH-52. CO-TARGETING ONCOSTATIN M RECEPTOR USING MONOCLONAL ANTIBODIES IN COMBINATION WITH PRESENT STANDARDS OF CARE FOR GLIOBLASTOMA
Authors: Burban Audrey , Sharanek Ahmad , Jahani-Asl Arezu
Published: November 2019

Glioblastoma Multiform (GBM) is the most aggressive primary tumor in the adult brain. The present standard of care includes surgical removal of the tumors followed by treatment with Temozolomide (TMZ) and radiation therapy. Despite intense efforts and advances in surgery and combination therapy, the median survival rate for GB patients remain 16 months following diagnosis. EGFRvIII/STAT3 signaling plays critical roles in GBM pathogenesis. We have recently discovered that the tumorigenic capacity of EGFRvIll/STAT3 pathway crucially depends on the cytokine receptor for Oncostatin M (OSMR). OSMR is a required co-receptor of EGFRvIII and a direct transcriptional target of STAT3. Strikingly, OSMR is highly expressed in brain tumor stem cells (BTSCs), a population of self-renewing malignant stem cells within GBM that contribute to tumor growth, recurrence and therapeutic resistance. We have generated therapeutic monoclonal antibodies against OSMR (OSMR mAb) that function as powerful inhibitors of OSMR. Treatment of BTSCs with OSMR mAb resulted in inhibition of OSMR-mediated signaling pathways and significantly impaired the phosphorylation of STAT3. Strikingly, treatment of BTSCs with OSMR mAb significantly attenuated BTSC self-renewal in limiting dilution assay and sensitized their response to tyrosine kinase inhibitors (TKI), ionizing radiation and TMZ. Using patient derived stem cell tumor xenografts, we have shown that OSMR mAb significantly reduced tumor growth compared to IgG control. Together, our findings suggest that targeting OSMR using therapeutic monoclonal antibodies in combination with EGFR inhibitors and/ or the current standard of care may provide a promising therapeutic strategy for glioblastoma.
EXTH-57. PRECLINICAL COMBINATION OF ONC201 WITH RADIOTHERAPY OR TEMOZOLOMIDE IN GBM, DIPG AND ATRT CELL LINES RESULTS IN DOPAMINE RECEPTOR ANTAGONISM, ATF4 INDUCTION AND CELL DEATH
Authors: Zhou Lanlan , El-Deiry Wafik
Published: November 2019

CNS tumors are one of the most lethal cancers in children and young adults. We previously reported that first-in-class small-molecule imipridone ONC201 can antagonize dopamine receptor D2 (DRD2), inactivate ERK/AKT, induce the integrated stress response (ISR), upregulate pro-apoptotic TRAIL receptor DR5, deplete cancer stem cells, and induce growth arrest or cell death in tumor cells. ONC201 crosses the blood-brain barrier and has induced durable tumor regressions in adult and pediatric H3K27M-mutant glioma patients. We hypothesized that ONC201 may synergize with radiotherapy or temozolomide in brain tumors. Glioblastoma (GBM: SNB19, T98G and U251), diffuse intrinsic pontine glioma (DIPG: SF8628) and atypical teratoid rhabdoid tumor (ATRT: BT-12, BT-16) cell lines were tested using cell viability or colony formation assays with ONC201 up to 20 μM alone or in combination with radiotherapy up to 8 Gy or temozolomide up to 100 μM. We observed synergy between ONC201 and radiation or temozolomide by multiple assays. We observed induction of PKA substrate phosphorylation as a marker of DRD2 antagonism, induction of ATF4 as a marker of ISR activation, and multiple markers of cell death in treated brain tumor cells. We are evaluating the relevance of mitochondrial protease ClpP, a recently described binding target of ONC201, in ONC201-induced glioma cell death. We have observed that knockdown of ClpP strongly protects multiple human cancer cell lines from ONC201-mediated cytotoxicity. Thus, we are exploring the potential interplay between ClpP, dopamine receptors, the ISR and TRAIL signaling pathways after single agent or combinatorial treatments. Our data suggests that ONC201 may be combined synergistically with temozolomide or radiation to address gliomas, along with potential pharmacodynamic biomarkers.
EXTH-62. STEM CELL DELIVERY OF ONCOLYTIC ADENOVIRUS DNX-2401 FOLLOWING SURGICAL RESECTION FOR THE TREATMENT OF GLIOBLASTOMA
Authors: Gopakumar Sricharan , Gumin Joy , Daou Marc , Ledbetter Daniel , McDonald Malcolm , Hossain Anwar , Hingtgen Shawn , Ewend Matthew , Lang Frederick
Published: November 2019

BACKGROUND

The oncolytic virus DNX-2401 (Delta-24-RGD) is a novel treatment of GBM. While prior studies have examined intratumoral injection of DNX-2401 into recurrent GBM, the potential of delivering DNX-2401 into the surgical resection cavity using tumor-tropic human mesenchymal stem cells (MSCs) has not been evaluated. We hypothesize that exploiting a fibrin-based scaffold for transplanting MSCs loaded with DNX-2401 (MSCs-DNX-2401) into the resection cavity will improve viral delivery, decrease GBM recurrence, and extend overall survival.

METHODS

MSCs-DNX-2401 were seeded in a fibrin matrix or suspended in PBS and placed in the upper wells of transwell plates with U87 cells placed below. After one week, U87 cells were counted to compare rates of cellular killing and confirm release of DNX-2401 from fibrin-seeded MSCs. U87 cells were transduced with mCherry-Luciferase and implanted into the brains of athymic mice (N=16). After fluorescence-guided surgical resection of glioma xenografts, MSCs (control) or MSCs-DNX-2401 were delivered in the resection cavity using a fibrin scaffold. Serial bioluminescence imaging (BLI) was used to monitor tumor recurrence.

RESULTS

In transwell experiments, MSCs-DNX-2401 seeded in fibrin were as effective as MSCs-DNX-2401 without the scaffold, indicating that fibrin did not negatively impact cell viability or viral release. In in vivo studies mimicking residual tumor after surgical resection, treatment of the post-resection cavity with MSCs-DNX-2401 suspended in fibrin permitted retention of MSCs-DNX-2401 within the tumor bed. Kaplan-Meier survival analyses revealed statistically significant improved survival after treatment with MSC-DNX-2401 in fibrin compared to controls with 50% of animals demonstrating complete responses according to BLI (p < 0.05).

CONCLUSION

Delivering DNX-2401 into the post-resection surgical cavity using MSCs seeded in fibrin is capable of eradicating residual GBM and prolonging overall survival. These studies support the clinical translation of this approach in newly diagnosed patients undergoing surgical resection of GBM.
EXTH-66. THERAPEUTIC VULNERABILITIES AND RADIOSENSITIZATION INDUCED BY IDH MUTANT DEPENDENT SUPPRESSION OF DNA DAMAGE REPAIR IN GLIOMA AND CHOLANGIOCARCINOMA
Authors: Wang Yuxiang , Wild Aaron , Chan Timothy
Published: November 2019

Mutations in isocitrate dehydrogenase (IDH) identified across cancer types lead to global changes to the epigenome that drive tumorigenesis. Yet, effectiveness of targeted therapies against mutant IDH remains unclear. Here we demonstrate that IDH-mutant glioma and cholangiocarcinoma patient specimens display elevated overall DNA damage responses. With tissue culture and multiple preclinical animal models of glioma and cholangiocarcinoma, we report that the reduced efficiency of DNA damage repair conferred by mutant IDH can be exploited by PARP inhibitors. Moreover, pharmacological effects of PARP inhibitors are dramatically enhanced by introducing concurrent, local ionizing radiation treatment to the animals. Thus, our study characterized the synergy of PARPi and radiation specifically towards IDH-mutant tumors, pointing out that in addition to ongoing trials using PARPi as mono agent, clinical trials that combine PARPi and radiation should be specifically considered. Furthermore, PARPi + RT may represent a readily translatable approach that is selective for tumor cells, transcends histologic origin, and has potential to improve outcomes in multiple diseases.
EXTH-69. NANOTHERAPEUTICS FOR NEUROSURGICALLY-APPLIED DRUG DELIVERY
Authors: Vasey Catherine , Taresco Vincenzo , Smith Stuart , Alexander Cameron , Rahman Ruman
Published: November 2019

Despite multimodal treatment, the median survival of Glioblastoma multiforme (GBM) patients remains less than 15 months, in considerable part due to diffusely infiltrative disease. Better treatment methods are necessary to eradicate residual tumour burden remaining beyond the resection cavity boundary. It is hypothesised that incorporating drug-loaded polymer pro-drug nanoparticles into a biodegradable microparticulate paste will lead to efficacious local delivery. We report the formulation of numerous self-assembling cytocompatible nanoparticles, based on different linear and branched polymeric architectures, amenable for localised intra-cavity delivery post-surgery. The polymers were synthesised by ring-opening polymerisation with organic catalysts, leading to controlled reaction kinetics and greater potential biomedical applicability. A simple nanoprecipitation technique was employed to gain nanoparticles with the size range of 60–130 nm, depending on the initial monomer ratios and polymeric architectures. Successful biocompatibility studies of the self-assembling nanoparticles have been carried out in vitro on the U87 glioma cell line. We demonstrated that copolymerisation of a monomer with functional capability enabled the successful conjugation of doxorubicin to the polymer chain. We will discuss strategies to incorporate pH-sensitive linkers to the polymeric backbone, which would allow controlled drug release in acidic microenvironments. Based on an increasing understanding of GBM intra-tumour heterogeneity, the capability to deliver multiple therapeutic moieties from single formulations is clinically-relevant. Thus, we hypothesised that polymers with a greater degree of branching over traditional linear structures would lead to greater drug loading, and successfully tested this hypothesis through the encapsulation of olaparib. Future work will assess the efficacy of the polymer pro-drug nanoparticles against both commercial and primary cell lines, and safety/efficacy of intra-cavity delivery using orthotopic syngeneic allografts, thus giving a more therapeutically-relevant insight into the activity of the formulations. This is the first study incorporating polymer pro-drugs of this type into an existing localised micro-scale delivery system for GBM therapies.