bluuebunny/crossref_metadata_2025_split huggingface dataset:
DDRE-06. CELLULAR STRESS RESPONSE IN DIPG THERAPY
Authors: Sridharan Sreepradha , Harmanci Arif , Siddaway Robert , Dobson Tara , Swaminathan Jyothishmathi , Sharma Ajay , Tarapore Rohinton S , Allen Joshua , Hawkins Cynthia , Khatua Soumen , Zaky Wafik , Gopalakrishnan Vidya 
Published: December 2020

Abstract
Diffuse Intrinsic Pontine Glioma (DIPG) is an incurable pediatric brain tumor of the pons and brainstem. Therefore, there is a desperate need for new therapeutics. Genomic profiling of tumors identified a highly prevalent dominant negative somatic mutation at lysine (K)-27 in histone genes HIST1H3B and H3F3A. Clonal evolution modeling suggests these mutations are truncal, and studies have demonstrated their contribution to tumorigenesis. ONC201, a first-in-class DRD2 antagonist and ClpP agonist is an anticancer drug developed by Oncoceutics, which targets the unfolded protein response (UPR) and integrated stress response (ISR) signaling and is actively being investigated in patients with recurrent H3 K27M-mutant gliomas. In adults with recurrent glioma, single agent studies showed benign-safety, no dose-limiting toxicities and a durable objective response when administered orally. In addition, intra-tumoral drug levels exceeded therapeutic thresholds, and induced tumor cell apoptosis. Based on this and response seen in a pediatric patient with DIPG for whom compassionate use of ONC201 was approved, a multi-arm, non-randomized multi-institutional Phase I clinical trial (NCT03416530) is actively accruing patients. However, the strength of UPR and ISR in DIPGs and their effect on DIPG response to ONC201 is not known. Our group employed bulk/single cell transcriptomic and single cell proteomic approaches to demonstrate substantial heterogeneity in UPR and ISR signaling in human DIPG samples. Consistent with this, DIPG cell lines exhibited considerable variability in sensitivity to ONC201. Single cell profiling identified tumor sub-populations with significant proliferative capacity even after ONC201 exposure. Incomplete response promotes recurrence. To target these cells, we performed a synthetic lethality screen with a library of 360 FDA-approved CNS penetrant compounds, which identified HDAC inhibitors and DNA damage-inducing chemotherapy as having synergy with ONC201. Thus, we suggest that tumor heterogeneity impacts sensitivity to ONC201 and that this can be reduced by combination treatments.
DDRE-08. POTENTIAL THERAPEUTIC EFFECTS OF ETOMOXIR IN COMBINATION WITH TEMOZOLOMIDE AGAINST HUMAN GLIOBLASTOMA TUMORSPHERES
Authors: Hyun Kim Eui , Shim Jin-Kyoung , Park Jungseong , Seon Jieun , Kim Hyun Sil , Moon Ju Hyung , Chang Jong Hee , Yook Jong In , Kang Seok-Gu 
Published: December 2020

Abstract

PURPOSE
Glioblastoma (GBM) is the most common and lethal brain tumor with the median survival between 10 and 14 months. Since current treatments including surgical resection, radiation and chemotherapy fail to cure GBM, a new strategy to maximize the efficacy is needed. Here, etomoxir, an inhibitor of fatty acid oxidation, has been combined with temozolomide, a standard treatment for GBM, to examine its anti-tumor effects. Etomoxir has shown anti-cancer effects against human bladder, prostate cancers as well as GBM. We hypothesize that etomoxir inhibits fatty acid metabolism in cancer cell to suppress tumor progression while temozolomide causes cancer cell death.

METHOD
Four kinds of human GBM tumorspheres (TSs) were treated with temozolomide or etomoxir alone, or in combination with each other. Therapeutic effects of two drugs were evaluated by measuring cell viability, apoptosis, neurosphere formation, 3D-invasion using collagen/matrigel matrix, and LC/MS analysis of energy metabolism. Protein and mRNA expression profiles after drug treatment were evaluated by western blotting and RNA-sequencing.

RESULTS
Combination treatment of temozolomide and etomoxir significantly inhibited the cell viability, stemness, and invasiveness in GBM TSs. Expression levels of stemness-, invasiveness-associated markers were also decreased by the combined treatment. The combined treatment also significantly inhibited ATP production in TCA cycle.

CONCLUSIONS
Our findings suggest that combined treatment of etomoxir and TMZ may be therapeutically effective in the treatment GBM
DDRE-09. DEVELOPING IDO-PROTACS TO IMPROVE IMMUNOTHERAPEUTIC EFFICACY IN PATIENTS WITH GLIOBLASTOMA
Authors: Bollu Lakshmi , Wainwright Derek , Zhai Lijie , Ladomersky Erik , Lauing Kristen , Bell April , Schlitz Gary 
Published: December 2020

Abstract

INTRODUCTION
Indoleamine 2,3-dioxygenase 1 (IDO; IDO1) is a rate-limiting enzyme that metabolizes the essential amino acid tryptophan into kynurenine. Recent work by our group has revealed that IDO promotes tumor development and suppresses immune cell functions independent of its enzyme activity. Moreover, pharmacologic IDO enzyme inhibitors that currently serve as the only class of drugs available for targeting immunosuppressive IDO activity, fail to improve the survival of patients with GBM. Here, we developed IDO-Proteolysis Targeting Chimeras (IDO-PROTACs). PROTACs bind to a specific protein and recruit an E3 ubiquitin ligase that enhance proteasome-mediated degradation of the target protein.

METHODS
A library of ≥100 IDO-PROTACs were developed by joining BMS986205 (IDO binder) with a linker group to various E3-ligase ligands. Western blot analysis of PROTAC-induced IDO degradation was tested in vitro among multiple human and mouse GBM cell lines including U87, GBM6, GBM43 and GL261 along a time course ranging between 1–96 hours of treatment and at varying concentrations. The mechanism of IDO protein degradation was investigated using pharmacologic ligands that inhibit or compete with the proteasome-mediated protein degradation pathway.

RESULTS
Primary screening identified several IDO-PROTACs with IDO protein degradation potential. Secondary screening showed that our lead compound has a DC50 value of ~0.5µM with an ability to degrade IDO in all GBM cells analyzed, and an initial activity within 12 hours of treatment that extended for up to 96 hours. Mutating the CRBN-binding ligand, pretreatment with the ubiquitin proteasome system inhibitors MG132 or MLN4924 or using unmodified parental compound all inhibited IDO protein degradation.

CONCLUSIONS
This study developed an initial IDO-PROTAC technology that upon further optimization, can neutralize both IDO enzyme and non-enzyme immunosuppressive effects. When combined with other forms of immunotherapy, IDO-PROTACs have the potential to substantially enhance immunotherapeutic efficacy in patients with GBM.
DDRE-13. DECONVOLUTING MECHANISMS OF RESISTANCE TO BRAF INHIBITORS IN BRAF V600E HUMAN GLIOMA
Authors: Schreck Karisa , Morin Andrew , Zhao Guisheng , Sanford Bridget , Green Adam , Jones Kenneth , Banerjee Anurhada , Nazemi Kellie , Samuel David , Kilburn Lindsay , Solomon David , Pratilas Christine , Nicolaides Theodore , Levy Jean Mulcahy 
Published: December 2020

Abstract

BACKGROUND
While BRAF-targeted therapy can be effective in a subset of patients with glioma, resistance to treatment can emerge over time. The description and validation of mechanisms of resistance in BRAF-mutant glioma are not previously described.

METHODS
Pre- and post- BRAF inhibitor (BRAFi) or BRAFi/MEK inhibitor (MEKi) treated patient samples were obtained under IRB-approved protocols at University of Colorado Denver, UCSF, and Johns Hopkins. Targeted DNA sequencing or whole exome sequencing (WES), and RNA-seq were conducted on paired samples. Functional validation of putative resistance mechanisms was performed using established glioma cell lines with BRAF V600E mutation (DBTRG-5MG, AM38, B76).

RESULTS
Analysis of 15 tissue sample pairs identified point mutations in 15 genes (including CBL, NF1, PTEN, and MAP2K1) and expression changes in RAF1 leading to putative mechanisms of resistance. We performed functional validation of loss of NF1 and CBL as resistance mechanisms and demonstrated growth inhibition and cell death in response to BRAFi with siRNA/sgRNA-mediated knockdown of each gene. Knockdown of CBL resulted in increased EGFR expression and phosphorylation, a possible mechanism for maintaining ERK signaling within the cell. Combination therapy with a MEKi or EGFR inhibitor was able to overcome resistance to BRAFi, in NF1 knockdown and CBL knockdown, respectively. Restoration of wild-type PTEN in B76 cells (PTEN-/-) restored sensitivity to BRAFi. Ingenuity pathway analysis suggested that a switch from BRAF to CRAF dependence mediated resistance in some tumors. Indeed, inhibition of CRAF expression using siRNA in a patient-derived glioma cell line re-sensitized cells to BRAFi.

CONCLUSIONS
Analysis of pre-/post-treatment BRAF mutant glioma sample pairs, primarily from pediatric patients, identified a variety of putative resistance mechanisms, some of which have been validated in vitro. Resistance mechanisms to BRAFi in glioma are varied and may be susceptible to different combinations of targeted therapy, highlighting the importance of a personalized approach.
DDRE-20. GENERATION OF A HIGH-AFFINITY EGFR/EGFRvIII-TARGETED D2C7 CAR-T CELL
Authors: Ryan Katherine , Wilkinson Daniel , Landi Daniel , Fecci Peter 
Published: December 2020

Abstract

BACKGROUND
The intent of this investigation is to validate a novel, high-affinity epidermal growth factor receptor (EGFR) chimeric antigen receptor (CAR) T-cell product for adoptive immunotherapy of EGFR-expressing malignancies of the central nervous system (CNS). Wild type EGFR is ubiquitously expressed on glial tumors in both children and adults, and the majority of solid tumors that metastasize to the CNS but is not expressed on healthy CNS tissues. EGFR and its isoform mutant, EGFRvIII, are hyperactivated or overexpressed receptor tyrosine kinases described in many human cancers. D2C7 is a recombinant monoclonal antibody short chain variable fragment (scFv) that binds to both wild type EGFR and EGFRvIII. We hypothesize that D2C7 adapted as a CAR on primary human T cells will generate potent, cytotoxic activity against EGFR-expressing tumors in vivo.

METHODS
In vitro interferon gamma release assays comparing the D2C7 CAR to the EGFRvIII CAR have proven that D2C7 CAR-T cells have high specificity and potent cytotoxicity against established murine glioblastoma (GBM) tumor cell lines, expressing both EGFR and EGFRvIII. Next steps include pre-clinical in vivo testing of the D2C7 CAR-T cells in murine models of CNS tumors expressing EGFR/EGFRvIII such as GBM, non-small cell lung carcinoma (NSCLC), breast carcinoma, and melanoma.

CONCLUSIONS
To improve and validate the effectiveness of CAR T-cell therapy for EGFR-expressing CNS tumors, our team has designed a high-affinity CAR-T cell that targets both EGFRvIII and wild-type EGFR, known as a D2C7 CAR-T cell. This investigation has established pre-clinical anti-tumor activity of D2C7-CAR T cells in vitro and we plan to present more mature data regarding efficacy in orthotopic murine models of GBM, NSCLC, breast carcinoma, and melanoma at the meeting this Fall.
DDRE-22. NOVEL LonP1 INHIBITORS FOR TARGETING GLIOMA STEM CELLS
Authors: Douglas Christopher , Di Kaijun , Lomeli Naomi , Bota Daniela 
Published: December 2020

Abstract
Glioblastoma (GBM) has an exceptional high rate of reoccurrence that largely explains its &lt; 15 months median survival. LonP1 is a serine protease that degrades misfolded proteins and regulates mitochondrial DNA replication. It drives tumor progression towards a malignant cancer phenotype in colorectal cancer, melanoma, oral cancer and cervical cancer. Dr. Daniela Bota has previously shown that LonP1 is overexpressed in human malignant gliomas and is associated with higher tumor grade and poor survival prognosis. In collaboration with Professor Bhaskar Das, we have used structure activity Relationship (SAR) analysis to generate compounds with on-target inhibition of LonP1 protease activity. Preliminary work on these novel compounds shows that these proprietary inhibitors can drastically decrease cell viability in the established D54 and U251 GBM lines. The lead compound BT317, shows on-target LonP1 and exceptional chymotrypsin-like proteasome inhibition. This has led to further testing, which has shown that BT317 has enhanced activity against glioma stem cell lines (GSC) and can cause global downregulation of hypoxia inducible factor 1 alpha (Hif1α) in a heterogenous GSC-derived organoid model. Finally, we have demonstrated that BT317 has less activity against differentiated GSC lines (e.g. through successive passages) and appears to have enhanced activity against TNFa-induced, differentiated GSC. This preliminary data highlights combinatorial, pharmacological LonP1 and proteasome inhibition as a novel strategy for targeting GSC in GBM.
DDRE-23. THE COMBINATION PARP INHIBITOR OLAPARIB WITH TEMOZOLOMIDE IN AN EXPERIMENTAL GLIOBLASTOMA MODEL
Authors: Hwang Kihwan , Go Kyeong-O , Kim Sang Ho , Lee Hyunwoo , Han Jung Ho , Kim Chae-Yong 
Published: December 2020

Abstract
Poly (ADP-ribose) polymerase (PARP) inhibition could enhance the efficacy of temozolomide and prolong survival in patients with glioblastoma. The aim of this study was to evaluate the combination of the PARP inhibitor olaparib with temozolomide in the treatment of glioblastoma by evaluating in vitro and in vivo antitumor effects in an experimental glioblastoma model. The authors investigated antitumor effects of olaparib on temozolomide-induced cytotoxicity on O6-methylguanine methyltransferase (MGMT) promotor methylated (U87MG, U251MG) and MGMT promotor unmethylated (T98G) glioblastoma cell lines using in vitro cell viability and apoptosis assay. We found that the combination of olaparib with temozolomide enhanced temozolomide-induced cytotoxicity in all glioblastoma cell lines regardless of the status of MGMT promotor methylation. For in vivo studies, nude mice bearing orthotopically xenografted glioblastoma cell lines (U87MG) were randomized to four experimental groups: (i) untreated, (ii) temozolomide alone, (iii) olaprib alone and, (iv) olaparib+temozolomide. Mice were treated daily for 4 weeks and monitored for tumor growth, and survival. However, the addition of olaparib had no impact on the efficacy of temozolomide. The combination of PARP inhibitor olaparib with temozolomide could be an effective therapeutic approach for treatment of glioblastoma regardless of MGMT promotor methylation status, although the efficacy still should be evaluated by in vivo and clinical studies.
DDRE-24. ACQUIRED RESISTANCE TO TARGETED INHIBITORS IN EGFR-DRIVEN GLIOBLASTOMA: IDENTIFICATION OF DUAL KINASE TARGETS
Authors: Shelton Abigail , Smithberger Erin , Butler Madison , Stamper Allie , Bash Ryan , Angus Steven , East Mike , Johnson Gary , Berens Michael , Furnari Frank , Miller C Ryan 
Published: December 2020

Abstract
Glioblastoma (GBM) is a devastating primary brain tumor with 5-year survival &lt; 5%. CDKN2A deletion (~60%) and EGFR amplification (55–60%) mutations frequently co-occur in these tumors. EGFR is an attractive therapeutic target due to its mutational frequency and availability of multiple brain-penetrant tyrosine kinase inhibitors (TKI). Several EGFR TKI have failed clinically, due in part to acquired resistance. To mechanistically examine this type of resistance, we used genetically engineered mouse astrocytes harboring Cdkn2a deletion and EGFRvIII, a common (35%) activating mutation. Resistant cells were generated via chronic exposure to gefitinib or erlotinib, either in vitro or in vivo. Resistance to these first-generation EGFR TKI conferred cross resistance (up to 36-fold ΔIC50) to a panel of second- and third-generation TKI relative to sensitive parental lines. Moreover, integrated RNA sequencing (RNA-seq) and chemical proteomics (multiplexed inhibitor beads and mass spectrometry (MIB-MS)) showed that the kinase transcriptome and proteome were rewired in resistant cells: 113 of ~300 detected kinases were differentially expressed (p&lt; 0.05). We then used these techniques to examine acute (≤ 48 h) kinome changes in both sensitive and resistant cells upon treatment with a CNS-penetrant, second-generation EGFR TKI, afatinib. Whereas exposure of treatment-naïve, sensitive cells to afatinib significantly rewired the kinome (120 differentially expressed kinases), the response of resistant cells to drug re-challenge was significantly blunted (13 differentially expressed kinases). A subset of expressed kinases (35 of 263) dynamically responded to afatinib in both sensitive and resistant cells. Overall, upregulated kinases include those implicated in the biology of gliomas (Bmx, Fgfr2) and of other cancers (Pdgfrb, Mapk3/4, Ddr1/2, Pdk2). These kinases thus represent putative druggable targets for dual inhibition therapy. Integrated kinome profiling using MIB-MS and RNA-seq in GBM models with defined mutational profiles provides a powerful framework to identify novel therapeutic targets that could significantly alter current treatment paradigms.
DDRE-26. TARGETING THE UNFOLDED PROTEIN RESPONSE POTENTIATES MARIZOMIB ANTITUMOR ACTIVITY IN GLIOBLASTOMA
Authors: Severin Christophe , Benitez-Hernandez Jorge , Dumitru C Dan , Beltran-Raygoza Nishdallyh , Flandin-Blety Pierre , Escoubet Laure , Rolfe Mark 
Published: December 2020

Abstract
Glioblastoma (GBM) is the most prevalent and aggressive malignant tumor of the central nervous system in adults. Patients with GBM have a poor prognosis, with a median survival of 15 months with current standard-of-care treatment, consisting of surgery followed by radiotherapy with concomitant and adjuvant temozolomide. Marizomib is an irreversible, pan-proteasome inhibitor that crosses the blood–brain barrier, currently under investigation in a phase 3 trial for newly diagnosed GBM. This preclinical study investigated the mechanism of action of marizomib in patient-derived GBM spheres and explored a series of combination treatments to further enhance its antitumor potency. Marizomib inhibited the 3 proteolytic subunits of the 20S proteasome in a dose-dependent manner, and this correlated with reduced cell proliferation compared with vehicle control (dimethyl sulfoxide). Marizomib induced transient expression of unfolded protein response (UPR) pathway genes, with a sustained upregulation of the SQSTMI gene. Combining marizomib with the histone deacetylase (HDAC) inhibitors panobinostat and vorinostat demonstrated cooperative upregulation of UPR genes and enhanced inhibition of cell proliferation. Furthermore, marizomib treatment upregulated survivin, an inhibitor of apoptosis protein (IAP). Compared with marizomib alone, addition of the IAP inhibitors AZD5582 and LCL161 increased marizomib antiproliferative activity in GBM spheres. In conclusion, these findings indicate that combining marizomib with HDAC or IAP inhibitors can enhance the overall antitumor activity of marizomib in patient-derived GBM spheres. Additional studies in preclinical models of GBM are needed to corroborate these findings.
EPCO-01. LUNG ADENOCARCINOMA BRAIN METASTASIS PREDICTION, PREVENTION, AND NON-INVASIVE DIAGNOSIS USING METHYLATION SIGNATURES WITHIN TISSUE AND CIRCULATING TUMOUR DNA
Authors: Zuccato Jeffrey , Mamatjan Yasin , Patil Vikas , Nassiri Farshad , Voisin Mathew , Aldape Kenneth , Zadeh Gelareh 
Published: December 2020

Abstract

BACKGROUND
One quarter of lung adenocarcinoma (LUAD) patients develop brain metastases (BM) and experience a poorer median survival of 12 months despite treatment. Clinical variables do not robustly predict who will develop BM and targeted preventative treatments are limited. Tumour DNA methylation signatures predict outcomes in other cancers and can be detected in circulating tumour DNA (ctDNA). This work predicts BM development from LUAD using methylation data, identifies novel potential treatment targets to prevent metastases, and detects LUAD-BM ctDNA non-invasively.

METHODS
DNA methylation profiling was undertaken on N=124 LUAD tumours. A gradient boosted regression model built on differentially methylated CpGs (DMCs) between tumours with and without BM in 70% of samples was validated in an independent 30% testing cohort. Nine paired BM samples were profiled and DMCs between their corresponding LUAD tissue were identified along with copy number (CN) alterations. A total of 47 LUAD-BM plasma samples underwent sequencing of immunoprecipitated methylated ctDNA and differentially methylated regions (DMRs) between LUAD-BM and intrinsic brain lesions were identified.

RESULTS
The methylation-based model significantly predicted time to brain metastasis development within the testing cohort independently from cancer stage in a multivariate analysis (HR=4.3, 95%CI 1.1–17, p=0.038). Genes/pathways involved in the process of brain metastasis were identified through assessment of 83K DMCs (FDR&lt; 0.2, mean difference &gt;|0.1|) between paired samples as well as the CN losses found in chromosome 12q/19 of BM samples. A total of 5.5K DMRs were identified that distinguish BM samples from gliomas or primary CNS lymphomas (FDR&lt; 0.05, logFC &gt;1).

CONCLUSIONS
DNA methylation signatures in lung adenocarcinomas predict brain metastasis development independently from prognostic clinical factors. Genes and pathways involved in metastasis were identified as novel potential therapeutic targets. Methylated circulating tumor DNA signatures differentiate lung brain metastases from other ring-enhancing brain lesions and may have potential for non-invasive diagnosis.
EPCO-06. MOLECULAR DETERMINANTS OF EVOLUTION AND PROGNOSIS AMONG DIFFUSE LOWER GRADE ASTROCYTOMAS
Authors: Kumar Mehul , Cairncross Gregory , Blough Michael , Bose Pinaki 
Published: December 2020

Abstract
Gliomas with wild type (WT) isocitrate dehydrogenase (IDH) are considerably more aggressive than those with mutant IDH. To identify putative drivers of the distinct progression trajectories of IDH WT and mutant disease, we analyzed transcriptomes of lower grade astrocytomas (LGAs; grade 2–3) with retention of 1p and 19q from The Cancer Genome Atlas (TCGA; n = 347). Compared to IDH mutant LGAs, we found that PDGF signaling was significantly enriched in IDH WT LGAs and that PDGFA was the top overexpressed gene in this pathway. We identified copy number gains of chromosome 7 in WT LGAs, and methylation of the PDGFA promoter in mutant LGAs, as candidate mechanisms for the differential expression of PDGFA. High PDGFA expression and low PDGFA promoter methylation were significantly associated with poor survival in all LGAs. We also found that PDGFA expression was positively associated with aneuploidy and extracellular matrix-related immunosuppressive features in WT LGAs, underscoring the role of PDGFA as a secreted mitogen. Finally, we show that the proportion of p53 pathway mutations increase significantly with grade in IDH WT gliomas. Taken together, our findings suggest that IDH WT LGAs evolve to higher grades, and ultimately to GBM, by progressive inactivation of the p53 pathway - functioning in concert with a background of increased PDGFA expression. These data emphasize the scope of genomic reprogramming that occurs in gliomas in relation to IDH mutations and further highlight the role of PDGFA in glioma formation, progression, and prognosis. Going forward, this work provides critical biological insight that may inspire new therapeutic strategies to suppress the transformation of IDH WT LGAs to higher-grade cancers.