bluuebunny/crossref_metadata_2025_split huggingface dataset:
DDRE-27. METABOLIC SWITCHING AS A MECHANISM OF DRUG RESISTANCE AGAINST NAMPT INHIBITION IN GLIOMAS
Authors: Sharma Pratibha , Puduvalli Vinay 
Published: November 2021

Abstract

BACKGROUND
Gliomas exhibit significant heterogeneity in treatment response and characteristically deploy resistance mechanisms that render conventional therapies ineffective. Recently, novel agents have been developed that target regulators of differential energy pathways specifically utilized by gliomas. We previously reported on the targeting of Nicotinamide Phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of the NAD+ salvage pathway and its essential role in glioma cell energy metabolism. Here, we determined the mechanisms by which glioma cells bypass blockade of energy metabolism and develop resistance to NAMPT inhibitors.

METHODS
Using isogenic parental and drug-resistant patient-derived glioma stem-like cells (GSCs), we examined adaptive changes after NAMPT inhibition in glycolysis, mitochondrial function (oxidative state, basal respiration rate, spare respiratory capacity, maximum respiration capacity and proton leak) and metabolite levels using Agilent Seahorse assay and targeted metabolomics. Cross reactivity across various NAMPT inhibitors was measured using Cell Titer Glo assay.

RESULTS
GSCs exposed for an extended period to sub-lethal doses of FK866, a potent NAMPT inhibitor, acquired drug resistance to the agent which were also cross-resistant to other NAMPT inhibitors. Drug-resistant GSCs showed a decrease in extracellular acidification rate and oxygen consumption rate compared to isogenic parental lines. Further, metabolomic analysis showed a high accumulation of glutamate, creatine and histidine metabolites in these cells. These results indicate a shift in metabolism of drug-resistant GSCs from carbon metabolism to nitrogen metabolism.

CONCLUSIONS
GSCs resistant to the NAMPT inhibitor, FK866 showed cross resistance to other NAMPT inhibitors indicating specificity of this effect. The resistance mechanism involves a shift of preferential energy generation from glycolysis to amino acid metabolism which allows the cells to use alternative methods to generate NAD. Additional results from ongoing studies to delineate the mechanisms of metabolic switch in the drug resistance lines will be presented that will help develop strategies to combat resistance to NAMPT inhibitors.
DDRE-30. CELL-PENETRATING PEPTIDE ANTAGONIST OF CCAAT/ENHANCER BINDING PROTEIN ß DISPLAYS POTENT ANTI-GLIOBLASTOMA ACTIVITY
Authors: Rotolo Jim , Ghamsari Lila , Ramierez Ricardo , Koester Mark , Leong Siok , Gallagher Erin , Darvishi Emad , Merutka Gene , Kappel Barry 
Published: November 2021

Abstract
CCAAT/Enhancer Binding Protein Beta (C/EBPß) is a transcription factor overexpressed in glioblastoma (GBM). Mechanistically, C/EBPß is a master regulator of mesenchymal transition in GBM, and its increased expression correlates with mesenchymal differentiation and predicts poor clinical outcome. C/EBPß activity requires dimerization with co-factors such as CREB/ATF family members via leucine zipper interactions. ST101 is a novel peptide antagonist of C/EBPß currently being evaluated in a Phase 1/2 clinical study in patients with advanced unresectable and metastatic solid tumors. ST101 binds to the C/EBPß leucine zipper, thereby preventing dimer formation and inhibiting its transcriptional activity, resulting in selective tumor cell cytotoxicity. Here, we describe ST101 non-clinical anti-tumor activity against GBM. In vitro studies in T98G and U251 cells demonstrate ST101 dose-dependent impact of cell viability (EC50 of 2.2 and 1.2 μM, respectively), accompanied by significant impact on C/EBPß-mediated gene expression as determined by qPCR analysis. In contrast, normal human mononuclear and epithelial cells were not sensitive to ST101 (EC50 &gt; 80 μM). In vivo, ST101 displayed significant anti-tumor activity in a U251 GBM subcutaneous xenograft model, resulting in 81.4% tumor growth inhibition (TGI) vs. control and undetectable tumors in 50% of animals. Following ST101 exposure tumors displayed reduced BIRC3 and ID2 gene expression, and significantly increased cleaved caspase 3 immunostaining indicative of cell death induction. In U251 tumors, subtherapeutic ST101 (&lt; 5% TGI) in combination with temozolomide (&lt; 5% TGI) resulted in 52.8% TGI, significantly greater than either single-agent alone. Similarly, in a temozolomide-refractory T98G GBM subcutaneous xenograft model, ST101 (41.6% TGI) in combination with TMZ (&lt; 5% TGI) resulted in significant anti-GBM response (72.4% TGI). These data emphasize the potential of ST101 as a potent peptide therapeutic for GBM.
DDRE-34. RIBONUCLEOTIDE REDUCTASE REGULATORY SUBUNIT M2 AS A DRIVER OF GLIOBLASTOMA TMZ-RESISTANCE THROUGH MODULATION OF dNTP PRODUCTION
Authors: Perrault Ella , Shireman Jack , Lin Peiyu , Ali Eunus , Zolp Andrew , Budhiraja Shreya , Park Cheol , Baisiwala Shivani , James David , Ben-Sahra Issam , Pott Sebastian , Basu Anindita , Ahmed Atique 
Published: November 2021

Abstract
Glioblastoma (GBM) remains one of the most resistant and fatal forms of cancer. Previous studies examine pre- and post-tumor recurrence; however, it is incredibly difficult to study tumor evolution during therapy where resistance develops. To investigate this, our lab performed a single-cell RNA-sequencing screen before, during, and after temozolomide-based (TMZ) chemotherapy in a patient-derived xenograft (PDX) model in vivo. Our analysis found 149 genes uniquely expressed during TMZ-therapy compared to pre- and post-therapy (p&lt; 0.0001). Of these, the ribonucleotide reductase (RNR) gene family stood out due to the preferential switch to Ribonucleotide Reductase Regulatory Subunit M2 (RRM2) during therapy. Classically, RRM2, or its isoform RRM2B, forms a complex with RRM1 to create an RNR, mediating deoxynucleoside triphosphate (dNTP) production. Our single-cell data revealed that GBM cells rely on RRM1-RRM2 interaction during therapy, but switch to RRM1-RRM2B in post-therapy recurrent GBM. In vitro, RRM2-knockdown cells increased TMZ susceptibility, whereas RRM1- and RRM2B-knockdowns were more resistant to TMZ (p&lt; 0.001). Immunocytochemistry found elevated yH2AX fluorescence in RRM2-knockdowns after TMZ treatment, signifying reduced DNA repair capacity compared to the control (p&lt; 0.001). To understand the mechanism of RRM2-mediated chemoresistance, targeted metabolomics was applied to quantify dNTP signatures during TMZ-therapy. In response to TMZ, dCTP and dGTP production in GBM cells increased 100-fold and 80-fold respectively (p&lt; 0.001). RRM2-knockdowns produced significantly less dCTP and dGTP (p&lt; 0.0001). By supplementing RRM2-knockdowns with dCTP and dGTP, TMZ-susceptibility was rescued, suggesting that RRM2 drives chemoresistance by promoting production of these two nucleotides. In vivo, following intracranial injection of GBM cells, mice treated with the RRM2 inhibitor Triapine with TMZ survived longer than those treated with TMZ alone, indicating promising clinical opportunities in targeting RRM2 (p&lt; 0.0001). Overall, our data present a novel understanding of how RRM2 activity is altered during therapeutic stress to counteract TMZ-induced DNA damage.
DDRE-37. YB-1 AS A BIOMARKER FOR DRUG RESISTANCE AND TUMOUR PROGRESSION IN MEDULLOBLASTOMA
Authors: Taylor Louisa , Kerr Ian , Coyle Beth 
Published: November 2021

Abstract
Medulloblastoma (MB) relapse is the most significant unmet clinical challenge in childhood cancer. Recently it has become evident that MBs display altered biology at relapse, indicative of the emergence and expansion of a minor, therapy resistant cancer cell population. Thus, the examination of mechanisms underlying therapy resistance is of critical importance. Y-box binding protein 1 (YB-1) is a multi-functional oncoprotein whose elevated expression and nuclear accumulation correlate with drug resistance, metastasis and disease progression in numerous cancers, although little is known about the functional role of YB-1 in MB. Genomic analysis of large-scale publicly available patient datasets revealed YB-1 expression is significantly elevated across MB molecular subgroups and high expression correlates with poor overall survival. Immunohistochemical analysis of YB-1 localisation in patient TMAs revealed significant YB-1 nuclear accumulation, suggestive of elevated YB-1 nuclear activity in these patients. Treatment of Group 3 MB cell lines (D283MED and HDMB-03) with cisplatin and subsequent analysis by nuclear/cytoplasmic fractionation and confocal microscopy revealed significantly increased nuclear and overall YB-1 expression, indicating a role for YB-1 in cellular stress response. In support of this, ChIP analysis in D283MED and HDMB-03 cell lines confirmed YB-1 interaction with multi-drug transporter gene ABCB1, while stable YB-1 knockdown resulted in significantly reduced ABCB1 expression. Likewise, knockdown of YB-1 expression in D283MED cells results in increased susceptibility of cells to vincristine, supporting a role for YB-1 in the acquisition of drug resistance in MB cell lines. Finally, whole transcriptome sequencing of YB-1-knockdown HDMB-03 and D283MED cell lines indicated YB-1 regulation of a variety of cell death, survival and metabolic pathways. We are currently using ChIP-Seq analysis to identify targetable YB-1 downstream “hits” which drive these processes. Ultimately, we aim to identify druggable targets of YB-1 allowing us to establish more effective therapeutic options for the treatment of high-risk MB.
EPID-02. COUNTY MEDIAN FAMILY INCOME AS PROGNOSTIC FACTOR IN NON-SMALL-CELL LUNG CANCER WITH BRAIN METASTASES AT PRESENTATION: A POPULATION-BASED STUDY
Authors: Jusue-Torres Ignacio , Hulbert Alicia , Zakaria Jehad , Albain Kathy S , Hentz Courtney , Melian Edward , Thakkar Jigisha P , Prabhu Vikram C 
Published: November 2021

Abstract

INTRODUCTION
The purpose of this study was to characterize the impact of household income disparities in the survival of patients with non-small cell lung cancer (NSCLC) presenting with brain metastasis on a population-based level.

METHODS
This is a population-based cohort study using the SEER database from 2010-2016 including 15,808 NSCLC patients presenting with brain metastasis. Two-tailed log-rank test was used to compare overall survival between groups and association with survival was quantified using hazard ratios (HR) with 95 % confidence intervals (CI) assessed with univariate and multivariate Cox proportional hazard models.

RESULTS
Patients living in low-income counties had a median survival of 4 months when compared to 5 months for patients living in high-income counties respectively (p&lt; 0.0001). Patients living in first and second bottom quartiles had a median survival of 4 months and 5 months and 6 months for the third and fourth top quartiles, respectively (p&lt; 0.0001). The 1-, 2- and 5-year survival rates for living in the lower household income quartile were 21, 10 and 3% respectively, for the second quartile 24, 10 and 3%; for the third quartile 28, 14 and 4% and for the top fourth quartile 31, 17 and 4% respectively. Multivariate cox proportional hazard analysis adjusted for age, gender, race, hispanic ethnicity, marital status, insurance status, percentage of high school education in the patient’s county, histology, presence of lung metastasis, bone metastasis, liver metastasis, radiation received, surgery performed, and chemotherapy received showed that living in higher quartile household income county is associated with decrease mortality risk (p &lt; 0.0001) HR 0.87 95% CI (0.82-92).

CONCLUSION
This population-based study suggests that living in higher median household income counties is associated with increased survival time and reduced risk of mortality for patients with NSCLC who have brain metastases present at diagnosis, independent of other factors.
EPID-21. EPIDEMIOLOGY AND RISK FACTORS OF PRIMARY CENTRAL NERVOUS SYSTEM (CNS) TUMORS IN CHILDREN AND ADULTS IN THE MIAMI CANCER INSTITUTE (MCI) COHORT
Authors: Ramirez-Menendez Miguel , Israel Shirlinka , Rubens Muni , Fernandez Alejandra , Diaz Zuanel , Hall Matthew , Mohler Alexander , Kotecha Rupesh , Odia Yazmin 
Published: November 2021

Abstract

BACKGROUND
Many epidemiological studies assess risk factors and incidence of primary CNS tumors in the United States; few describe the incidence in specific geographic locations. Environmental or ethnic/racial factors may affect the incidence of primary CNS tumors. Miami-Dade County (MDC) is an ethnically-diverse US county, with 69.4% Hispanic, 12.9% White Non-Hispanic, 15.5% Black Non-Hispanic, Asian 1.6%, 0.3% Native, and 0.3% other. We characterized primary CNS tumors at Miami Cancer Institute (MCI) relative to national reports.

METHODS
We reviewed electronic medical records for all patients (n=1221) diagnosed with CNS tumors at MCI from 2017 to 2021. Descriptive and statistical analyses assessed environmental and clinical variables.

RESULTS
Malignant CNS tumors account for 74% of MCI primary CNS tumors. Diffuse gliomas (41%), meningiomas (26%), and embryonal tumors (5%) were the most common histologies; embryonal tumors most common at younger ages (median: 18 years). The most abundant histological subtypes were glioblastoma (54%), benign meningioma (92%), and medulloblastoma (73%), respectively. Ethnic/racial composition of glioma patients at MCI was 55.9% Hispanic, 24.6% White Non-Hispanic, 6.4% Black Non-Hispanic, 1.8% Other Non-Hispanic, 1.3% Asian, 10% unreported, comparable to MDC. Compared to national averages, the age distribution at MCI was higher among lower grade gliomas (range: 15-96, Median: 61 years), yet lower for malignant gliomas (range: 1-93, median: 47 years). The incidence of malignant CNS tumors did not differ by gender; benign primary CNS tumors were significantly more frequent in females (245/324, 76%; p&lt; 0.001). Smoking history did not associate with incidence of primary CNS tumors; 793/1221 (65%) self-reported as non-smoker.

CONCLUSION
The ethnic/racial composition and incidence of primary CNS tumors by histology at MCI significantly differs from national CBTRUS database (Ostrom et al). This cohort will be further characterized by genetic profiles, race, diet, allergies, family history, substance use, clinical trial enrollment, therapeutic modalities, and overall survival rate.
IMMU-19. EVALUATING EFFECTS OF REVERSING DISTINCT FACETS OF IMMUNOSUPPRESSION IN EXPERIMENTAL GBM
Authors: Ayasoufi Katayoun , Tritz Zachariah , Fain Cori , Khadka Roman , Jin Fang , Hansen Michael , Johnson Aaron 
Published: November 2021

Abstract
Glioblastoma is associated with severe and multifaceted immunosuppression affecting all immune organs. Immunosuppression in GBM is a critical barrier to the success of immunotherapies and patient survival. We demonstrated that immunosuppression in the GL261-model of experimental GBM presents with significant thymic and spleen atrophy, MHCII downregulation, presence of potent immunosuppressive factors in serum, and sequestration of T-cells in the bone marrow. Parabiosis studies determined that soluble factors mediate immunosuppression by inhibiting T-cell proliferation, thymic involution, and loss of peripheral T-cells. In contrast, bone marrow T-cell sequestration was not mediated through soluble factors. While the immunosuppression in GBM is severe, a causative link between each facet of immunosuppression and overall survival is lacking. We used two strategies to block T-cell sequestration into the bone marrow and evaluated the extent survival was impacted in experimental GBM. First, we evaluated the extent a novel and off-the-shelf combination immunotherapy that uses extended 1/2-life IL-2 and anti-PD-1 reverses bone marrow T-cell sequestration. Sham treatment or anti-PD1 monotherapy did not alter T-cell sequestration in the bone marrow and animals had no enhanced survival. Extended 1/2-life IL-2 monotherapy and combination strategy both prevented T-cell sequestration into the bone marrow. However, only combined therapy, which also prevented MHC class II downregulation, improved survival. Second, we determined that glioma-bearing adrenalectomized mice do not present with bone marrow T-cell sequestration. However, sera of glioma-bearing adrenalectomized mice is as immunosuppressive as glioma-bearing controls. Blocking bone marrow T-cell sequestration in the presences of serum immunosuppression led to no survival benefit in glioma-bearing adrenalectomized mice compared to controls. In short, bone marrow T-cell sequestration alone does not correspond with overall survival in experimental glioma. Importantly, a concerted effort to reverse MHC class II downregulation and define inhibitory circulating factors may have the highest impact in immunotherapeutic efficacy and improving patient survival.
IMMU-25. SYNERGY BETWEEN TMZ AND INDIVIDUALIZED MULTIMODAL IMMUNOTHERAPY TO IMPROVE OS OF IDH1 WILD TYPE MGMT PROMOTOR UNMETHYLATED GBM PATIENTS
Authors: Van Gool Stefaan , Makalowski Jennifer , Schirrmacher Volker , Stuecker Wilfried 
Published: November 2021

Abstract
The prognosis of IDH1 wild type MGMT promotor unmethylated (MGMT-p-UM) GBM patients remains poor. Addition of TMZ to radiotherapy shifted the median OS from 11.8 to 12.6 months (Stupp, Lancet Oncol 2019). We retrospectively analysed the value of individualized multimodal immunotherapy (IMI) to improve OS in these patients. Adults with first event of IDH1wt GBM and documented status of MGMT-p-UM, and treated with IMI in the period June 2015 till July 2020, were selected. IMI consisted of 1/ immunogenic cell death (ICD) therapy (NDV injections + modulated electrohyperthermia), 2/ active specific immunotherapy with autologous mature dendritic cells loaded with tumor lysate or ICD therapy-induced serum-derived antigenic extracellular microvesicles and apoptotic bodies (IO-Vac® is an approved advanced therapy medicinal product since 27/05/2015), 3/ modulatory immunotherapy adapted to the patient, and 4/ complementary medicines. Twenty-eight patients (11f, 17m) had a median age of 48y (range 18-69) and a KPI of 90 (50-100). Extent of resection was complete (11), &lt; complete (9) or not documented (8). Seven patients were treated with surgery/radio(chemo)therapy and subsequent IMI (Group-1); 21 patients were treated with radiochemotherapy followed by maintenance TMZ + ICD therapy, followed by DC vaccines (Group-2). Both groups received further maintenance ICD therapy. Age, KPI and extent of resection were not different amongst both groups. PFS was not assessed because of challenges about pseudoprogression. The median OS of group-1 patients was 11m (2y OS: 0%). Surprisingly the median OS of group-2 patients was 18m with 2y OS of 17% (CI95%: +31, -15), which was significantly (Log-rank: p = 0.027) different from group-1. The data suggest that addition of IMI after local therapy on its own has no relevant effect on OS in IDH1 wild type MGMT-p-UM GBM patients, similar to maintenance TMZ. However, the combination of both TMZ + IMI significantly improves median OS.
IMMU-31. TUMOR-SPECIFIC ALTERNATIVE SPLICING GENERATES SPATIALLY-CONSERVED HLA-BINDING NEOANTIGEN TARGETS DETECTED THROUGH INTEGRATIVE TRANSCRIPTOMIC AND PROTEOMIC ANALYSES
Authors: Kwok Darwin , Nejo Takahide , Costello Joseph , Okada Hideho 
Published: November 2021

Abstract

BACKGROUND
While immunotherapy is profoundly efficacious in certain cancers, its success is limited in cancers with lower mutational burden, such as gliomas. Therefore, investigating neoantigens beyond those from somatic mutations can expand the repertoire of immunotherapy targets. Recent studies detected alternative-splicing (AS) events in various cancer types that could potentially translate into tumor-specific proteins. Our study investigates AS within glioma to identify novel MHC-I-presented neoantigen targets through an integrative transcriptomic and proteomic computational pipeline, complemented by an extensive spatiotemporal analysis of the AS candidates.

METHODS
Bulk RNA-seq of high tumor purity TCGA-GBM/LGG (n=429) were analyzed through a novel systematic pipeline, and tumor-specific splicing junctions (neojunctions) were identified in silico by cross-referencing with bulk RNA-seq of GTEx normal tissue (n=9,166). Two HLA-binding prediction algorithms were subsequently incorporated to predict peptide sequences with high likelihood for HLA-presentation. Investigation of the tumor-wide clonality and temporal stability of the candidates was performed on extensive RNA-seq data from our spatially mapped intratumoral samples and longitudinally collected tumor tissue RNA-seq. Proteomic validation was conducted through mass-spec analysis of the Clinical Proteomic Tumor Analysis Consortium (CPTAC)-GBM repository (n=99).

RESULTS
Our analysis of TCGA-GBM/LGG bulk RNA-seq identified 249 putative neojunctions that translate into 222 cancer-specific peptide sequences which confer 21,489 tumor-specific n-mers (8-11 amino acids in length). Both prediction algorithms concurrently identified 271 n-mers likely to bind and be presented by HLA*A0101, HLA*A0201, HLA*A0301, HLA*A1101, or HLA*A2402. We confirmed the expression of 15 out of 58 HLA*A0201-binding candidates in HLA*A0201+ patient-derived glioma cell line RNA-seq with a subset of candidates conserved spatially. Analysis of CPTAC-GBM mass-spec data detected 23 tumor-specific peptides with 5 containing detected n-mers highly predicted to be HLA-presented.

CONCLUSION
Tumor-specific neojunctions identified in our unique integrative pipeline present novel candidate immunotherapy targets for gliomas and offer a new avenue in neoantigen discovery across cancer types.
INNV-03. DEVELOPMENT OF A NOVEL DUAL-MODALITY BALLOON IMPLANT FOR SIMULTANEOUS HIGH-DOSE-RATE BRACHYTHERAPY AND MAGNETIC NANOPARTICLE HYPERTHERMIA OF BRAIN TUMOR RESECTION CAVITIES
Authors: Wan Shuying , Rodrigues Dario , Stauffer Paul , Kwiatkowski Janet , Khanna Omaditya , Judy Kevin , Yu Yan , Shi Wenyin , Hurwitz Mark 
Published: November 2021

Abstract

PURPOSE
To develop a novel thermobrachytherapy (TBT) balloon implant that delivers hyperthermia and radiation simultaneously, with three specific aims: 1) to fabricate a prototype TBT balloon device; 2) to verify compatibility of all heating and radiation delivery components and evaluate heat and radiation dosimetry in full size skull/brain phantom models; and 3) to characterize in vivo heating patterns in pig brain.

METHODS
Five 3cm diameter TBT balloons were fabricated. Each balloon has two layers: an inner layer to be filled with saline to expand the resection cavity, and an outer layer to be filled with magnetic nanoparticle (MNP) solution to absorb energy from an external magnetic field hence generate heat. The balloon shaft houses 4 ports to fill inner and outer layers, insert a high-dose-rate brachytherapy source into the balloon center, and a fiber optic sensor into the outer layer to monitor and control balloon temperature. A 3D-printed skull phantom was filled with brain tissue-equivalent gel for in-phantom measurements of heating around a TBT balloon. Optically stimulated luminescent dosimeters and Gafchromic film were used to measure radiation dose; while motorized temperature probes placed in catheters were inserted in surrounding gel for thermal mapping. For in vivo experiments, a 1cm balloon was specifically fabricated for pigs 40-50 kg.

RESULTS
The presence of MNP, magnetic field, and 43-55°C heating did not affect radiation dose significantly. Thermal mapping demonstrated spherically symmetric heating in both phantom and in vivo brain tissue, where a higher concentration of MNP and stronger magnetic field of 1.6-4.5 kA/m at 133 kHz was used to achieve temperatures of 55°C in the much smaller balloon.

CONCLUSION
Novel dual-modality balloons have been fabricated and tested successfully in the lab and in vivo, hence providing crucial information to validate thermal modeling for combined heat and radiation treatment of brain tumor resection cavities.