bluuebunny/crossref_metadata_2025_split huggingface dataset:
EXTH-03. IODINE NANOPARTICLE RADIOTHERAPY OF HUMAN BREAST CANCER GROWING IN THE BRAINS OF ATHYMIC MICE
Authors: Hainfeld James , Ridwan Sharif M , Stanishevsky Yaroslav , Smilowitz Henry 
Published: December 2020

Abstract
About 30% of breast cancers metastasize to brain; those widely disseminated are fatal typically in 3–4 months, even with the best available surgery, drugs, and radiotherapy. To address this dire situation, we have developed iodine nanoparticles (INPs) that target brain tumors after intravenous (IV) injection. The iodine then absorbs X-rays during radiotherapy (RT), creating free radicals and local tumor damage, effectively boosting the local RT dose at the tumor. Efficacy was tested using the very aggressive human triple negative breast cancer (TNBC, MDA-MB-231 cells) growing in the brains of athymic nude mice. With a well-tolerated non-toxic IV dose of the INPs (7 g iodine/kg body weight), tumors showed a heavily iodinated rim surrounding the tumor having an average uptake of 2.9% iodine by weight (peaks at 4.5%), calculated to provide dose enhancement factors of ~5.5 (peaks at 8.0) -- the highest ever reported for any radio-sensitizing agents. With 15 Gy, single dose RT, all animals died by 72 days; INP pretreatment resulted in longer-term remissions with 40% of mice surviving 150 days and 30% surviving &gt; 280 days. Fluorescence confocal microscopy revealed most INP staining co-localized with CD31in the tumor center and periphery. Greatest INP/CD31 staining was in the tumor periphery, the region of increased MicroCT contrast. Tumor cells line irregularly-shaped spaces (ISS) with INP, CD31 staining very close to or on the tumor cell surface and PAS stain on their boundary and may represent a unique form of CD31-expressing vascular mimicry in intracerebral 231-tumors. INP/CD31 co-staining is also seen around ISS formed around tumor cells migrating on CD31+blood-vessels. The significant radiation dose enhancement to the prolific INP-binding ISS found throughout the tumor but concentrated in the tumor rim, may contribute significantly to the life extensions observed after INP-RT; VM could represent a new NP, particularly INP, tumor-homing target.
EXTH-06. INTEGRATED MOLECULAR PROFILING REVEALS TARGETABLE MOLECULAR ABNORMALITIES SHARED ACROSS MULTIPLE HISTOLOGIES OF BRAIN METASTASIS
Authors: Fukumura Kazutaka , Malgulwar Prit Benny , Fischer Grant , Hu Xiao Ding , Debeb Bisrat Godefay , Yu Dihua , Davies Michael , Huse Jason 
Published: December 2020

Abstract
Brain metastases (BMs) occur in approximately 20–40% of patients with advanced cancer, and the estimated prevalence of new BMs in United States is between 200,000–300,000 per year. While the incidence of BM has increased over the past decades due to improvements in brain tumor detection technology, the prognosis is still very poor with the median overall survival times from weeks to few months. Therefore, identification of the precise molecular landscape and therapeutic targets for BMs is absolutely essential in tangible improvement of patient management. Here, we performed integrated genomic, transcriptional, and proteomic profiling in a cohort of lung, breast, and renal cell carcinomas consisting of both BMs and patient-matched primary or extracranial metastatic tissues to identify shared cellular and molecular factors driving BMs across distinct primary tumor histologies. Although the comprehensive analysis identified the unique genomic, transcriptional and proteomic landscapes according to the different histopathologies, elevated PI3K/AKT and RAS/MAPK signaling was observed as a generalizable feature across the entire specimen cohort, along with relative immunosuppression and metabolic upregulation of the electron transport chain (ETC). Interestingly, immunosuppression via T cell depletion was significantly associated with unfavorable prognosis of patients with BMs, and ETC inhibition as the prospective therapeutic target for BM patients was demonstrated using in vitro and in vivo disease models. Taken together, our findings suggest that abnormalities involving oncogenic signaling, metabolism, and the immune microenvironment are shared across multiple histologies of BMs, and may be amenable to therapeutic targeting.
EXTH-08. MINIPIG MODELS OF NEUROFIBROMATOSIS TYPE 1 FOR THERAPEUTIC DEVELOPMENT
Authors: Watson Adrienne , Osum Sara , Taisto Mandy , Tschida Barbara , Duerre Dylan , Moertel Christopher , Kirstein Mark , Largaespada David , Oribamise Eunice 
Published: December 2020

Abstract
Neurofibromatosis Type 1 (NF1) is a genetic disease caused by mutations in the neurofibromin 1 (NF1) gene. NF1 patients present with a variety of clinical manifestations and are predisposed to cancer development. Many NF1 animal models have been developed, yet none display the spectrum of disease seen in patients and the translational impact of these models has been limited. Using gene-editing technology, we have developed a minipig model of NF1 that exhibits clinical hallmarks of the disease, including café au lait macules, neurofibromas, and optic pathway glioma. We have conducted pharmacological studies in our NF1 minipigs to assess the pharmacokinetic and pharmacodynamic properties of MEK inhibitors for NF1. We have demonstrated that oral administration of several MEK inhibitors results in clinically relevant plasma concentrations and consequent inhibition of Ras signaling in immune cells, and certain MEK inhibitors can cross the blood brain barrier and have a pharmacodynamic effect, suggesting that they may be effective in treating NF1-associated brain tumors. Because over 20% of NF1 patients harbor NF1 nonsense mutations, we are assessing safety and efficacy of nonsense mutation suppressors that may be effective in treating NF1. We evaluated six drugs known to induce nonsense mutation suppression in several primary cell types isolated from NF1 minipigs and show that several of these drugs have the propensity to induce the production of full length neurofibromin protein, leading to a subsequent reduction in MAPK signaling. Information acquired from this NF1 minipig preclinical model will be leveraged towards initiating a clinical trial in NF1 patients. The NF1 minipig provides an unprecedented opportunity to study the complex biology and natural history of NF1 and could prove indispensable for development of imaging methods, biomarkers, and evaluation of safety and efficacy of NF1 therapies.
EXTH-09. NEO-ADJUVANT TEMOZOLOMIDE INCREASES THE EFFICACY OF SUBSEQUENT CONCURRENT CHEMORADIATION IN A TRANSGLUTAMINASE-2 DEPENDENT MANNER
Authors: Daniel Paul , Meehan Brian , Sabri Siham , Shenouda George , Sarkaria Jann , Rak Janusz , Abdulkarim Bassam 
Published: December 2020

Abstract
Glioblastoma (GBM) is invariably fatal due to failure of current chemoradiation (Stupp) regimes. Biomarkers such as MGMT have proven to predict response to Temozolomide (TMZ). An equivalent biomarker for radiation (RT) has not yet been identified. Transglutaminase-2 (TGM2) has been implicated in driving radiation resistance; but the mechanism is poorly understood. We have investigated how exposure to neoadjuvant TMZ in glioma stem cells (GSCs) with different levels of TGM2 would affect the response to RT. MATERIALS/METHODS: Primary GSCs lines with different TGM2 levels (high: 1123, 83; low: 528, OPK49) were used to explore the role of TGM2 in RT response and modulation of expression by TMZ in vitro and in-vivo. RESULTS: We showed that TGM2 drives radioresistance in GSCs through restriction of p53 mediated repression of RAD51 expression. We demonstrate that exposure of GSCs to TMZ drives rapid downregulation of TGM2 in vitro and this phenomenon is recapitulated in vivo. Interestingly, we confirm that RT is able to drive reciprocal changes in TGM2 and promotes reactivation of TGM2 in TGM2-high tumours but not TGM2-low tumours. Given these observations, we hypothesized that exposure to neoadjuvant TMZ in TGM2-low tumours would increase the efficacy of subsequent RT in these tumours. Comparison of the effect of standard treatment consisting of 3 weeks of concurrent TMZ and RT (Stupp) to a novel regime (neo-Stupp) consisting of 1 week of neoadjuvant TMZ followed by two weeks of TMZ and hypofractionated RT revealed a superior survival benefit of this novel regime in TGM2-low tumours but not in TGM2-high tumours. Utilization of the TGM2 inhibitor GK921 in combination with neo-Stupp prevented rapid relapse previously observed in TGM2-high tumours. CONCLUSION: We provide evidence that TGM2 is a biomarker of RT response and can be used to tailor chemoradiation protocols to the unique biology of each individual GBM patient.
EXTH-12. INHIBITION OF CBP/p300 HISTONE ACETYLATION ACTIVITY ENHANCES TEMOZOLOMIDE ACTIVITY IN GLIOBLASTOMA PATIENT DERIVED XENOGRAFTS
Authors: Kitange Gaspar J , Burgenske Danielle M , Bakken Katrina K , Hu Zeng , He Lihong , Carlson Brett L , Wilson Jonathan , Bommi-Reddy Archana , Conery Andy , Sarkaria Jann 
Published: December 2020

Abstract
There is an unmet need to identify novel targets that can sensitize temozolomide (TMZ) or prevent resistance in GBM. We have demonstrated that retinoblastoma binding protein 4 (RBBP4) interacts with p300 to modulate expression of genes involved in homologous recombination (HR), including RAD51. In vitro, RBBP4- or p300-shRNA significantly sensitized TMZ in patient derived xenograft (PDX) GBM43 cells (relative fluorescence for 100µM TMZ treated control shNT cells was 0.89 ± 0.1 vs 0.47± 0.09 and 0.39 ± 0.01 for shRBBP4 and shp300, respectively (p&lt; 0.01)). TMZ sensitization increased DNA damage signaling through phosphorylation of KAP1 (p-KAP1) and p-CHK1. Moreover, RBBP4- or p300-shRNA delayed the repair of TMZ-induced DSBs evidenced by persistent gH2AX. Silencing RBBP4 or p300 reduced acetylation of lysine 27 of histone H3 (H3K27Ac) within promoters of HR genes regulated by RBBP4/p300 complex. Thus, RBBP4/p300 complex controls gene expression through p300-mediated histone acetyltransferase (HAT) activity, suggesting that p300 inhibitors could sensitize GBM to TMZ. Accordingly, CBP/p300 inhibitor CPI1612 significantly suppressed H3K27Ac and HR repair genes, including RAD51. Moreover, CPI1612 sensitized TMZ in GBM43 (synergy score = 258), and TMZ/CPI1612 significantly suppressed growth of GBM39 PDX cells compared with either drug alone (confluence (%) was 92 ± 1.0 (DMSO), 76.5 ± 4.6 (10 µM TMZ), 62 ± 3.4 (10 nM CPI1612) and 21.9 ± 3.2 (TMZ 10 µM/CPI-CPI1612 10 nM). CPI1612 enhanced TMZ-induced DSBs with increased damage signaling through p- KAP1 and persistent gH2AX. Pharmacodynamics studies in GBM39 orthotopic mice models revealed that oral CPI1612 penetrates the brain and accumulate in tumor regions and suppresses H3K27Ac without significant weight loss in mice that received placebo, TMZ, CPI1612 alone or combined TMZ/CPI-1612, demonstrating good animal tolerability. Collectively, these findings are encouraging that CBP/p300 inhibition by the brain penetrant CPI-1612 is a potential strategy for enhancing the efficacy of TMZ in GBM.
EXTH-14. A NOVEL LONG-ACTING INTERLEUKIN-7 AGONIST, NT-I7, INCREASES CYTOTOXIC CD8 CELLS AND ENHANCES SURVIVAL IN MOUSE GLIOMA MODELS
Authors: Ghosh Subhajit , Yan Ran , Thotala Sukrutha , Jash Arijita , Mahadevan Anita , Hu Tong , Lee Byung Ha , Yang Se Hwan , Hallahan Dennis , Chheda Milan , Thotala Dinesh , Campian Jian 
Published: December 2020

Abstract

BACKGROUND
Patients with glioblastoma (GBM) are treated with radiation (RT) and temozolomide (TMZ). These treatments can cause prolonged severe lymphopenia, which is associated with shorter survival. NT-I7 (efineptakin alfa) is a long-acting recombinant human IL-7 that supports the proliferation and survival CD4+ and CD8+ cells in both human and mice. We tested whether NT-I7 would protect T cells from treatment-induced lymphopenia and improve survival.

METHODS
C57BL/6 mice bearing intracranial tumors (GL261 or CT2A) were treated with RT (1.8 Gy/day x 5 days), TMZ (33 mg/kg/day x 5 days) and/or NT-17 (10 mg/kg on the final day of RT completion). We followed for survival and profiled CD3, CD8, CD4, FOXP3 in peripheral blood over time. In parallel, we assessed cervical lymph nodes, bone marrow, thymus, spleen, and the tumor 6 days after NT-I7 treatment.

RESULTS
Median survival in mice treated with NT-I7 combined with RT was significantly better than RT alone (GL261: 40d vs 34d, p&lt; 0.0021; CT2A: 90d vs 40d, p&lt; 0.0499) or NT-I7 alone (GL261: 40d vs 24d, p&lt; 0.008; CT2A: 90d vs 32d, p&lt; 0.0154). NT-17 with RT was just as effective as NT-I7 combined with RT and TMZ in both GL261 (40d vs 47d) and CT2A (90d vs 90d). NT-I7 treatment significantly increased the amount of CD8+ cells in the peripheral blood and tumor. NT- I7 rescued CD8+ T cells from RT induced lymphopenia in peripheral blood, spleen, and lymph nodes. NT-I7 alone or NT-I7 in combination with RT increased the CD8+ T cells in peripheral blood and tumor while reducing the FOXP3+ T-reg cells in the tumor microenvironment.

CONCLUSIONS
NT-I7 protects T-cells from RT induced lymphopenia, improves cytotoxic CD8+ T lymphocytes systemically and in the tumor, and improves survival. Presently, a phase I/II trial to evaluate NT-I7 in patients with high-grade gliomas is ongoing (NCT03687957).
EXTH-17. LOCAL DELIVERY OF CYTOKINES AND SYNTHETIC IMMUNOMODULATORS INCREASES T CELL INFILTRATION AND SIGNIFICANTLY IMPROVES SURVIVAL IN A POORLY IMMUNOGENIC MODEL OF GLIOBLASTOMA
Authors: Haddad Alexander , Spatz Jordan , Collins Sara , Pereira Matheus , Gill Sabraj , Montoya Megan , Chuntova Polly , Young Jacob , Mummaneni Nikhil , Kasahara Noriyuki , Aghi Manish 
Published: December 2020

Abstract

BACKGROUND
Severe local and systemic immune suppression in glioblastoma (GBM) contributes to the failure of single-agent immunotherapies in clinical trials. In this study, we evaluated the efficacy of locally delivered combination immunotherapy in a poorly immunogenic murine GBM model.

METHODS
Immunomodulators used in these studies included: IL-15 and IL-7 (T cell activation), LIGHT (T cell tumor infiltration), FLT3L (dendritic cell maturation/proliferation), a surface T cell engager (T cell killing of tumor cells), and a bispecific PD-L1/T cell engager (T cell killing targeted to PD-L1-expressing cells). We first assessed T cell-mediated cytotoxicity in vitro against SB28, a poorly immunogenic murine GBM cell line, after expressing these immunomodulators in combination. Next, tumor growth inhibition in vivo was evaluated in syngeneic C57BL/6 mice, initially by establishment of intracranial tumors with pre-transduced SB28 cells, and subsequently by delivering these immunomodulators to pre-established naïve SB28 tumors using neural stem cells (NSCs) and retroviral replicating vectors (RRV).

RESULTS
SB28 cells transduced with immunomodulators activated dose-dependent T cell-mediated cytotoxicity in vitro. Mice with pre-transduced intracranial SB28 gliomas showed significantly longer survival (minimum survival: 60 days, long-term survival in 57% of mice) vs. control mice (median survival: 20 days) (p&lt; 0.001), and significantly increased tumor infiltration of CD4+ and CD8+ T cells. NSC- and RRV-mediated immunomodulator delivery to pre-established SB28 gliomas also resulted in significantly increased survival of treated mice vs. controls (median survival: 31 days vs. 22 days, p&lt; 0.001). Immunomodulator-treated tumors again showed significantly increased infiltration of CD4+ and CD8+ T cells, along with decreased CD11b+ cell infiltration.

CONCLUSIONS
A novel combination therapy for GBM immunotherapy activated T cell killing of SB28 GBM cells in vitro and achieved a significant survival benefit in vivo, associated with anti-tumor alterations to the GBM tumor microenvironment. Further studies to optimize the efficiency of combinatorial immunomodulator delivery are currently underway.
EXTH-20. SYNGENEIC B7-H3-SPECIFIC CAR T-CELLS HAVE POTENT ANTI-BRAIN TUMOR ACTIVITY VIA LOCAL OR SYSTEMIC DELIVERY
Authors: Haydar Dalia , Yi Zhongzhen , Houke Haley , Roussel Martine F , DeRenzo Chris , Gottschalk Stephen , Krenciute Giedre 
Published: December 2020

Abstract

BACKGROUND
We and others have identified B7-H3 (CD276) as a promising target for CAR T-cell-based immunotherapies for pediatric brain tumors. So far, B7-H3-CAR T cells have only been studied in xenograft models for brain tumors, which do not recapitulate the immunosuppressive tumor microenvironment (TME). To overcome this obstacle, we decided to adapt the immune competent GL261 murine glioma model which mimics human disease and host immune barriers.

METHODS
To evaluate their safety and efficacy, murine B7-H3-CAR T-cells were generated using retroviral particles encoding a 2nd generation B7-H3-CAR with a CD28.z signaling domain. Expansion, persistence, and anti-tumor activity were evaluated in vitro and in vivo. Components of the brain TME were then evaluated using flow cytometry and immunostaining.

RESULTS
B7-H3-CAR T cells only killed B7-H3+ tumor cells, secreted significant levels of IFNγ and IL-2 in an antigen-dependent manner and expanded an average of 85-fold in repeat stimulation assay with B7-H3+ tumor cells in contrast to control CAR T-cells. In vivo, intratumoral (2x106) or systemic (3x106) injection of syngeneic B7-H3-CAR T-cells into mice with orthotopic GL261 glioma induced complete regression in 60% of treated mice resulting in a significant survival advantage. Mice showed no evidence of acute or long-term toxicities related to CAR T-cell infusions. We confirmed this encouraging safety profile by systemic administration of a high dose (1x107) B7-H3-CAR T-cells and performing histological analyses of all major organs on day 14 post T-cell injection, which showed no notable signs of injury or on-target/off-tumor toxicities.

CONCLUSIONS
We successfully generated syngeneic B7-H3-CAR T-cells and have demonstrated that these cells have potent anti-tumor activity in the immune competent GL261 glioma model via local or systemic delivery without apparent toxicities. Our study paves the way for future testing of B7-H3-CAR T-cells in early phase clinical studies.
EXTH-36. PHARMACEUTICAL INHIBITION OF CYCLIN DEPENDENT KINASE 4/6 (CDK4/6) IN GLIOBLASTOMA
Authors: Nuga Oluwademilade , Meng Yuling , Berezovsky Artem , Nelson Kevin , de Carvalho Ana 
Published: December 2020

Abstract
Potent and selective CDK4/6 inhibitors (CDK4/6i) have potential for treating glioblastoma. Although genomic abnormalities affecting CDK4/6-RB1 signaling axis, such as CDK4 or CDK6 amplification and CDKN2A deletion, which are frequent in GBM, have been proposed to predict response of RB1-wildtype GBM to CDK4/6i, there is not enough data validating these biomarkers as sufficient for patient selection. Here we employ a panel of GBM patient derived cancer stem cells (CSC) representing the most frequent somatic genomic alterations in GBM to test their response to CDK4/6i. Twelve CSC lines were treated in quintuplicate for 4–7 days with 0–10 mM Abemaciclib, Ribociclib or vehicle control. Cell viability was measured using CellTiterGlo and dose response curves were analyzed using GRmetrics in R to determine Area Above the Curve (AAC) and IC50, factoring variable growth rates among cell lines. Experiments were repeated 2–4 times. Abemaciclib was more potent in reducing cell viability, based on the RB1-null CSC line measured resistance (mean AAC = 0.3 +/- 0.06), ribociclib was more specific (mean AAC = 0.05 +/-0.01). 4/7 CSCs with CDKN2A homozygous deletion were sensitive (mean AAC &gt; 0.7) while 3/7 were resistant (mean AAC &lt; 0.33) to 4 and 7-day treatments of abemaciclib. One CSC from a newly diagnosed GBM bearing CDK4, MYC and EGFR amplifications was sensitive to both inhibitors (mean AAC = 0.5 abemaciclib and ribociclib), while CSC from the matched recurrent tumor presenting the same driver genomic alterations was significantly more resistant (mean AAC = 0.2 for abemaciclib and ribociclib) (p &lt; 0.05, t-test). Additionally, we exposed a sensitive cell line to conditioned media from a resistant cohort, resulting in significantly reduced proliferation and increased resistance to CDK4/6i (p&lt; 0.05, Dunn). These findings underscore the importance of a utilizing a robust molecular profiling approach in evaluating which patients will benefit from CDK4/6i therapy.
EXTH-38. ORTHOGONAL IN VIVO MODELS WERE THE SOLE PRECLINICAL PREDICTOR OF CLINICAL EFFICACY IN PHASE 1 TRIALS OF TARGETED THERAPIES FOR GLIOBLASTOMA: RESULTS OF A SYSTEMATIC REVIEW
Authors: Gunjur Ashray , Balasubramanian Adithya , Hafeez Umbreen , Menon Siddharth , Cher Lawrence , Parakh Sagun , Gan Hui 
Published: December 2020

Abstract

INTRODUCTION
No drug has improved survival in recurrent glioblastoma despite encouraging activity preclinically. We undertook a systematic review of matched preclinical and Phase 1 trials (P1Ts) of targeted agents to investigate potential preclinical predictors of clinical efficacy.

METHODS
We identified all adult glioblastoma monotherapy P1Ts of targeted agents & preceding preclinical data published between 2006–2019 via structured searches of EMBASE/MEDLINE/PUBMED. For preclinical studies, data regarding in vitro models, in vivo models (species, implantation site, cell-line type) and efficacy (growth inhibition, regression rate, survival) were extracted. For P1T, response rate (RR) data were collected as absolute (%) and categorical (RR&lt; 5% vs. RR≥ 5%) variables. Associations were compared by chi-square/Fisher’s exact test, Kruskal-Wallis or Mann-Whitney U testing as appropriate with 2-sided p-values.

RESULTS
We found 28 P1Ts with median RR 2.9% (range 0.0–33.3%) and mOS 8.0mo (range 4.6–13.0mo). Seven (25%) had ‘minimal’ published pre-clinical data (5 missing entirely; 2 in vitro only); 12 (43%) utilised one cell line in vivo (‘single model’ group); and 9 (32%) used 2+ biologically distinct in vivo models (‘orthogonal’ group). There was strong reliance on U87-based cell lines (14/21 (71%)) in the latter groups. None of the variables tested were associated with RR except for use of ‘orthogonal models’. Compared to the ‘orthogonal’ group, the P1T RR rate was lower in ‘single’ and ‘minimal’ groups (6.8% vs 1.2%, p= 0.043 and 6.8% vs 0.0%, p= 0.026 respectively). The frequency of P1T with a RR &gt; 5% was also higher in the ‘orthogonal’ compared to the same two groups (78% vs 20%, p= 0.042 and 78% vs 17%, p= 0.041).

CONCLUSION
The availability of good quality pre-clinical data, especially the use of orthogonal models in vivo, was significantly associated with P1T response rates and warrants further investigation as a minimal threshold of evidence in future drug development.