bluuebunny/crossref_metadata_2025_split huggingface dataset:
EXTH-16. THE ORAL IRON-MIMETIC GALLIUM MALTOLATE SUPPRESSES TREATMENT-RESISTANT GLIOBLASTOMA – IN VIVO VALIDATION
Authors: Al-Gizawiy Mona , Wujek Robert , Prah Melissa , Connelly Jennifer , Chitambar Christopher , Schmainda Kathleen 
Published: November 2022

Abstract

BACKGROUND
We previously reported on our in vitro and in vivo studies using the metallocompound gallium maltolate (GaM) to target glioblastoma (GBM). We demonstrated a profound cytotoxic effect in vitrov and in vivo. Additionally, our preliminary in vivo data suggested a substantial inhibitory effect on tumor growth, as well as a significant extension of disease-specific survival (OS). Here, we further validate the inhibitory effects of GaM in vivo.

METHODS
In vitro irradiated adult GBM U87-MG cells were stereotactically implanted into the right striatum of male and female athymic rats. Advanced MR imaging at 9.4T was carried out weekly starting two weeks after implantation. Daily oral GaM (50 mg/kg) or vehicle were provided on tumor confirmation. Longitudinal advanced MRI parameters were processed for enhancing tumor ROIs in OsiriX 8.5.1 (lite) with Imaging Biometrics Software (Imaging Biometrics LLC,). Statistical analyses included Kaplan-Meier survival plots, linear mixed model (LMM) comparisons, and t-statistic for slopes comparison (as indicator of tumor growth rate).

RESULTS
Median OS for the male pilot cohort (5 control, 5 GaM) was 28 and 51 days, respectively; 31 and 59 days for the male replication cohort (1 control, 3 GaM); 37 and 48 days for the female replication cohort (6 control, 7 GaM). GaM-treated xenograft tumors grew significantly slower than control tumors with sex and time dependent growth rates. No significant differences were seen between male and female cohorts in both control and treatment groups at all timepoints. Hence, subsequent analyses were performed on pooled data. Median OS was 30.5 days and 48 days for control and GaM groups, respectively (p &lt; .001). A strong correlation between treatment and survival (Χ2 = 6.238187; p = .0125) and tumor growth suppression (LMM; p &lt; .0001) was evident.

CONCLUSION
We have successfully validated the inhibitory effects of GaM on GBM growth in vivo.
EXTH-19. OPTIMIZING MDM2 INHIBITION FOR THE TREATMENT OF GLIOBLASTOMA
Authors: Rendo Veronica , Lee Eudocia , Khuu Nicholas , Pelton Kristine , Lapinskas Emily , Wen Patrick Y , Ligon Keith , Beroukhim Rameen 
Published: November 2022

Abstract
Over 60% of glioblastomas retain wild-type p53, resulting in potential susceptibility to MDM2 inhibitors. These molecules disrupt the interaction between p53 and its negative regulator MDM2, allowing downstream pathway signaling and cell fate decisions including growth inhibition and death resulting from cellular stress. We have analyzed clinical samples from 10 patients newly diagnosed with glioblastoma multiforme (GBM) and treated with the MDM2 inhibitor KRT-232. We detected upregulation of CDKN1A transcript (a target of p53) in all p53 wild-type tumors (8 of 10), but not in p53-mutant tumors (2 of 10). In patient-derived cell lines, treatment with KRT-232 at the clinically detected concentration was only sufficient to stall tumor growth. Cell death via apoptosis can be achieved when MDM2 inhibition is combined with the chemotherapeutic agent temozolomide. As the effects and resistance mechanisms of MDM2 inhibition remain poorly understood in GBM, we have additionally performed genomic and transcriptomic analyses in patient-derived cell lines to better characterize sensitive tumors and identify putative biomarkers of drug response. Dose response curves and growth assays showed that tumors with inactivating p53 mutations are highly resistant to treatment, but those that retain wild-type p53 exhibit various degrees of drug sensitivity. This suggests that other factors, in addition to p53 mutational status, mediate response to MDM2 inhibition in gliomas. Transcriptional analyses of patient samples following drug treatment suggest that cell division, chromatin reorganization, cell differentiation state and immune response programs become deregulated under MDM2 inhibition and in the absence of p53-inactivating mutations.
EXTH-26. MICROGLIA-SPECIFIC DISRUPTION OF SIALIC ACID-SIGLEC-9/E INTERACTIONS: A NOVEL IMMUNOTHERAPY AGAINST GLIOBLASTOMA?
Authors: Schmassmann Philip , Roux Julien , Tatari Nazanin , Martins Tomas A , Ritz Marie-Françoise , Shekarian Tala , Laeubli Heinz , Hutter Gregor 
Published: November 2022

Abstract
Recently, ‘don’t eat me’-signals like CD47 have emerged as novel innate immune checkpoints, enabling cancer cells to evade clearance by phagocytes such as microglia (MG) or monocyte-derived cells (MdCs). Here, we aim at defining the role of inhibitory Siglec-9 in human and its mouse homologue Siglec-E in innate-centered immunotherapy against GBM. TCGA RNA-sequencing data revealed a significant correlation between high expression of immunoinhibitory SIGLEC9 and poor survival in GBM patients (log-rank p = 0.02). Using a CT-2A orthotopic GBM mouse model with MG-specific spatio-temporal deletion of Siglece (Sall1CreERT2 x Sigleceflox) , we observed high MG-proliferation upon Siglece knockout (Ki-67+ MG 14.8% in Crenegvs. 34.9% in Creposp &lt; 0.0001) accompanied by an enhanced microglial GBM-cell uptake (5.6% in Crenegvs. 12.3% in Crepos, p &lt; 0.001). By extending the Siglece knockout to the MdC compartment (Cx3cr1CreERT2x Sigleceflox) we observed a significantly prolonged survival in the Crepospopulation (21d in Crenegvs. 27d post-tumor injection in Crepos, p = 0.018), which could be further promoted by combining Siglece knockout with CD47 blockade (11% long-term remission in Crepos+ anti-CD47). Proteomics analysis revealed increased antigen processing and presentation capabilities of SigleceKOMdCs which was confirmed by ex-vivo OT-1 cross-presentation assays. This increased T cell priming upon MdC SigleceKOwas further boosted by addition of anti-PD1 antibody to the SigleceKO+ anti-CD47 combination. Resulting in 23% of animals experiencing long-term remission in the triple treatment arm, even after tumor re-challenge. Genetic targeting of sialic acids, the ligand for Siglec receptors, on CT-2A cells (GNE-KO), resulted in increased GBM-cell phagocytosis by MG and MdCs and less exhausted tumor-infiltrating CD8+ T cells (14.8% in WT vs. 5.9% in GNE-KO, p = 0.003). In a translational approach, we are currently testing anti-Siglec-9 treatment regimens in patient GBM explants, cultured for 5 days in perfusion bioreactors.
EXTH-35. ANTI-TUMOR AROMATHERAPY FOR MALIGNANT BRAIN TUMORS USING VOLATILE COMPONENTS OF HIBA ESSENTIAL OIL
Authors: Saito Norihiko , Hirai Nozomi , Nagata Takuya , Kushida Naoki , Sato Sho , Hiramoto Yu , Hayashi Morito , Iwabuchi Satoshi 
Published: November 2022

Abstract

INTRODUCTION
Glioblastoma is a brain tumor with a very poor prognosis that is highly resistant to treatment. Hiba (Thujopsis dolabrata) has been used as a building material because of its insect repellent effect and refreshing fragrance. In this study, we analyzed the antitumor effects of thujopsen, which is contained in the essential oil of hiba, and investigated its antitumor aroma therapy.Methods and

RESULTS
We investigated the anti-tumor aroma effect of hiba essential oil on glioblastoma cells (U251, T98G), gastric cancer cells (MKN45), and breast cancer cells (MCF7). The anti-tumor effect of hiba essential oil varied depending on the carcinoma, with strong inhibition of cell proliferation observed in MKN45, U251, and T98G cells. Hinokitiol in hiba essential oil has been reported to have antitumor effects, and we isolated and identified a new antitumor factor, thujopsene, by liquid chromatography analysis. In tumor cell proliferation assays, thujopsen inhibited tumor cell proliferation more rapidly and potently than hinokitiol. Comparing the reach of the two compounds, hinokitiol showed a broader anti-tumor effect than thujopsen. The expression of caspase-3 and caspase-9 was increased by thujopsen, and DARTS analysis identified PKM2 as an intracellular binding protein of thujopsen.

DISCUSSION
The present study revealed that thujopsen induces apoptosis via caspase-3 and caspase-9. Furthermore, unlike hinokitiol, thujopsen was suggested to exhibit antitumor effects mediated by PKM2.

CONCLUSION
Thujopsen is a low molecular weight compound and easily evaporates into the air, it is expected to be applied to a new glioblastoma therapy using "aroma".
EXTH-40. DIPGS SUPPRESS THE EFFICACY OF T CELL THERAPIES THROUGH DYSFUNCTIONAL IMMUNE SYNAPSE FORMATION
Authors: Ibanez Jorge , Houke Haley , Elayan Abdul , Ocasio-Adorno Jennifer , Hebbar Nikhil , Velasquez Paulina , Baker Suzanne , Krenciute Giedre 
Published: November 2022

Abstract
Diffuse intrinsic pontine gliomas (DIPGs) are highly lethal pediatric brain tumors. Thus, there is an urgent need for novel therapeutics. While chimeric antigen receptor (CAR) T-cell therapy has the potential to meet this need and early phase clinical studies with CAR T cells have shown safety and some efficacy, additional studies are needed to understand the lack of efficacy of CAR T cells against DIPGs. The goal of this study was to identify CAR T cell efficacy limiting factors in DIPG setting. To study that, we focused on targeting GRP78, an endoplasmic reticulum chaperone protein that is broadly expressed on the cell surface of DIPGs. We generated GRP78-specific CAR T cells and compared their effector function against U87 glioma and the patient-derived DIPG007 cell line. Despite that GRP78-CAR T cells recognize and kill U87 and DIPG007 tumor cells in vitro, they were only effective against U87 in vivo. In addition, in vitro cytokine production and T cell proliferation were heavily diminished in DIPG007, compared to U87. For full activation, T cells require a cell-to-cell interaction and the formation of a highly organized structure called immune synapse (IS). Experiments using confocal microscopy showed that the IS quality, measured as lytic granule accumulation and cytoskeleton organization at the IS, was impaired in DIPG007 when compared to U87. This dysfunctional IS correlated with poor T cell activation (calcium flux) as determined by live cell imaging. We observed the same dysfunctional IS formation regardless of CAR T cell specificity and targeted antigen expression level, indicating that the suppressive effect is DIPG tumor mediated. In summary, we demonstrate that DIPGs suppress CAR T cell effector function through dysfunctional IS formation. We are now testing genetic engineering approaches directed at improving IS formation to overcome the suppressive effects of DIPGs.
EXTH-43. XPO1 INHIBITOR SELINEXOR SENSITIVITY IN GLIOBLASTOMA: POTENTIAL ROLE OF MGMT ACTIVATION THROUGH PKA-CREB PATHWAY
Authors: Suzuki Yuta , Gupta Shiv , Sarkaria Jann , Kitange Gaspar 
Published: November 2022

Abstract

INTRODUCTION
Glioblastoma (GBM) is the most common and aggressive form of adult brain tumor and is an incurable disease due to primary and secondary resistance to therapy. We recently examined the candidate genes modulating temozolomide (TMZ) resistance using genome-wide shRNA screening in TMZ-resistant U251 (U251TMZ) model. We identified a total of 134 TMZ-resistant candidate genes, including Karyopherin A1 (KPNA1) and Exportin 1 (XPO1), the genes critical for nucleocytoplasmic (NC)-transport. Interestingly, XPO1 inhibitor Selinexor is an FDA-approved agent for refractory multiple myeloma, and there is an ongoing interest in evaluating Selinexor for GBM therapy. Therefore, we hypothesized that Selinexor is a promising drug for overcoming TMZ resistance. METHODS and

RESULTS
We conducted a series of experiments in vitro using Selinexor with and without TMZ. Selinexor and TMZ alone didn’t significantly block the growth of U251TMZ cells. In contrast, Selinexor significantly re-sensitized resistant U251TMZ cells to TMZ. Interestingly, MGMT-methylated GBM39 cells were sensitive to Selinexor alone, TMZ alone, and to combined Selinexor/TMZ treatment. Contrarily, MGMT-unmethylated GBM43 cells were only sensitive to combined Selinexor/TMZ treatment. These findings suggested that similar to TMZ, Selinexor sensitivity may be influenced by MGMT expression status, with MGMT expressing cells showing resistance. In line with this notion, re-expression of exogeneous MGMT blocked sensitivity of MGMT-methylated U251 cells to Selinexor and TMZ, but such inhibition was not observed in U251 expressing vector alone. Interestingly, the concentration-dependent experiments demonstrated that Selinexor can induce MGMT expression in unmethylated T98G, GBM6, GBM14, and GBM43 cells. Selinexor-induced MGMT expression was accompanied with increased phosphorylation of CREB protein.

CONCLUSION
These results suggest that Selinexor sensitivity alone and with TMZ may be limited to MGMT-methylated GBM cells and may increase MGMT expression in unmethylated cells through activation of PKA-CREB pathway. Future studies will evaluate how MGMT may impact the sensitivity of GBM cells to Selinexor.
EXTH-48. INHIBITION OF SREBP-1 IS SYNTHETICALLY LETHAL WITH BCL-XL/BCL-2 INHIBITION IN GLIOBLASTOMA IN VITRO
Authors: Tosin Davide , Schlotter Dominik , Hajosch Annika , Hlavac Michal , Westhoff Mike-Andrew , Siegelin Markus , Wirtz Christian Rainer , Karpel-Massler Georg 
Published: November 2022

Abstract

OBJECTIVE
A cellular homeostasis that is shifted away from apoptosis and a reprogramming of the lipid metabolism are both, features that are frequently encountered in glioblastoma. This study aimed at investigating whether interference with the lipid metabolism is synthetically lethal with inhibition of anti-apoptotic Bcl-2 family proteins in glioblastoma in vitro.

METHODS
Established (U251) and primary-cultured glioblastoma cells (PC38, PC40 and PC128) as well as glioblastoma stem-like cells (SC38 and SC40) were treated with the Bcl-xL/Bcl-2 inhibitor ABT-263 (navitoclax) and/or the SREBP-1 inhibitor Fatostatin. MTT-assays were performed to assess effects of the combination therapy on the cell viability. Isobolograms were calculated to characterize the drug-drug interaction. Spheroids were used to determine anti-proliferative effects in a 3-dimensional setting. Staining with annexin V/propidium iodide and flowcytometric analysis were performed to assess pro-apoptotic effects. For molecular analyses, Western blots and specific knock-down experiments with siRNA were performed.

RESULTS
Combined targeting of SREBP-1 and Bcl-xL/Bcl-2 led to a synergistic inhibitory effect on the cellular viability of established, primary-cultured and glioblastoma stem-like cells as well as spheroids. This effect was shown to be at least in part mediated by enhanced apoptosis and to occur in a caspase-dependent manner. On the molecular level, treatment with increasing concentrations of Fatostatin led to a downregulation of Mcl-1.

CONCLUSION
Our study indicates that combined inhibition of Bcl-xL/Bcl-2 and interference with the lipid metabolism targeting SREBP-1 synergistically induces caspase-dependent apoptosis in glioblastoma cells. This effect can also be observed in more complex 3-dimensional glioblastoma cell formations. Further studies will focus on deciphering the drug-induced alterations of the metabolic pathways that are responsible for the synergistic effect of this therapeutic strategy.
EXTH-49. A NOVEL THERAPEUTIC ANTIBODY TARGETING DIFFUSE MIDLINE GLIOMA
Authors: Balakrishnan Illango , Madhavan Krishna , Pierce Angela , Venkataraman Sujatha , Vibhakar Rajeev 
Published: November 2022

Abstract
There is an unmet need to identify novel targeted therapies for H3K27M mutated Diffuse Midline Gliomas. (DMG) Using genetic overexpression and deletion of H3K27M in model cells we identified high expression of CD99 mRNA in H3K27M-mutant expressing DIPGs compared to other normal brain counterparts. A cell surface antigen screen confirmed that CD99 was highly expressed in DMG compared to normal tissues. We then developed a novel chimeric CD99 antibody based on a human IgG4 scaffold and tested the anti-tumor efficacy of this antibody in vitro and in vivo DMG xenografts. Our new CD99 antibody (10D1) significantly reduced DIPG tumor cell proliferation in vitro. In vivo intravenous administration of the antibody in orthotopic DMG tumor bearing mice showed complete clearance of tumor with prolonged animal survival establishing anti-tumor efficacy of 10D1 and demonstrating its ability in crossing the blood-brain-pons barrier. Loco-regional administration of 10D1, intratumorally or to the lateral ventricle, showed similar anti-tumor effects at reduced antibody concentrations while limiting systemic effects on normal T cells. 10D1 combined with radiation to further prolong the survival of orthotopic xenograft-bearing animals. In conclusion, we have identified a novel therapeutic for DMG which is now in further development.
EXTH-51. HSV-PTENΑ TREATMENT TARGETS GLIOMA STEM CELLS TO REDUCE STEMNESS AND SENSITIZES GLIOBLASTOMA TO IRRADIATION
Authors: Mullarkey Matthew P , Sahu Upasana , Hong Bangxing , Kaur Balveen 
Published: November 2022

Abstract
Glioblastoma is one of the most lethal and treatment-resistant tumors of the central nervous system. Despite maximal surgical and medical therapy, survival remains dismal with a median of 21 months. Despite advances in treatment, this has only led to modest survival benefit. A significant challenge in treatment of glioblastoma is targeting glioma stem cells (GSCs) which are a source of therapy resistance. Oncolytic viral (OV) therapy is a promising therapy for solid tumors that preferentially targets tumor cells for lysis and an anti-tumor immune response while sparing normal cells. Among all OVs, oncolytic Herpes Simplex Virus (oHSV) is substantially ahead in the clinic, with an oHSV T-VEC approved by the FDA for metastatic melanoma treatment and G47∆ which received conditional approval for the treatment of GBM in Japan. In prior work, our group has demonstrated that PTENα expression by an oHSV (HSV-P10) results in improved long-term survivors in intracranial tumor-bearing mice compared to HSVQ treatment. We aim to elucidate the mechanism of improved therapeutic efficacy of HSV-P10 against GBM and evaluate if HSV-P10 may overcome radio-resistance. RNA sequencing and GSEA analysis of primary human GBM cells infected with control HSVQ or HSV-P10 reveals that while HSVQ virus infection leads to an increase in genes regulating IL6-STAT3 pathway, pivotal in maintaining stemness properties, HSV-P10 infection leads to a reduction. HSV-P10 reduces CD133+/CD44+ stem cells, induces DNA damage and sensitizes the GBM cells to irradiation. Our findings reveal a novel mechanism induced by HSV-P10 in combination with irradiation where HSV-P10 modulates IL6-STAT3 signaling downregulating genes associated with stemness (Nestin, Sox2). HSV-P10 infection in combination with irradiation reduces GSC tumor sphere formation in vitro and sensitizes GBMs to radiotherapy in an intracranial mouse xenograft model. Our findings uncover a possible mechanism to overcome GSC-mediated therapy resistance to improve the therapeutic efficacy for GBM.
EXTH-61. RPP25L IS A NOVEL DEPENDENCY IN GLIOBLASTOMAS WITH LOW RPP25 EXPRESSION
Authors: Aquilanti Elisa , Chen Rebecca , Hui Keliana , Kageler Lauren , Prensner John , Wen Patrick Y , Meyerson Matthew , Huang Franklin 
Published: November 2022

Abstract
Genetic redundancy is a property whereby two or more genes encode for the same biological function, and inactivation of one redundant gene has little effect on the overall phenotype. In recent years, genetic redundancy has been exploited as a cancer therapeutic strategy, as individual paralogs of essential genes are occasionally lost in cancers because of genomic deletions. Inactivation of the non-deleted paralog can therefore be selectively toxic to tumor cells. To identify cancer cells that may become reliant on the non-methylated paralog of essential genes, we performed an in-silico analysis of the correlation between DNA methylation and genetic dependency across large scale CRISPR knockout screens that revealed novel paralog dependencies. Through this analysis, we identified glioblastoma cell lines with hypermethylation of the RPP25 promoter and with sensitivity to loss of RPP25L. RPP25 is a known structural component of RNAse P, a key enzyme involved in tRNA maturation. While the biological function of RPP25L is unknown, it has significant sequence homology to RPP25. We used CRISPR editing and CRISPR interference to inactivate RPP25L in a panel of glioblastoma cell lines and demonstrated that cell lines that do not express RPP25 (SF295, GB1, LN18) exhibit a rapid reduction in viability upon RPP25L loss, whereas cell lines with retained RPP25 expression or re-expressed RPP25 are not affected. RPP25L dependency is associated with a marked reduction in nascent polypeptide formation as determined by click chemistry. Lastly, we validated RPP25L dependency in glioblastoma patient-derived neurospheres with loss of RPP25 expression. These results indicate that RPP25L is a promising novel therapeutic target in glioblastomas with hypermethylation of the RPP25 promoter.
EXTH-67. PRECLINICAL ASSESSMENT OF THE EFFICACY OF MPT0B640, AN ORALLY BIOAVAILABLE SMALL MOLECULE HSP90 INHIBITOR, AGAINST GLIOMAS
Authors: Sharma Pratibha , Xu Jihong , Chen Xiaohua , Huo Longfei , Ju Zhenlin , Li Ziyi , Ban Kechen , Seah Ethan , Sampath Deepa , Puduvalli Vinay 
Published: November 2022

Abstract

BACKGROUND
Heat-shock protein 90 (HSP90), an evolutionary conserved protein, is a key member of the epichaperome complex involved in maintenance of protein homeostasis during non-stress and stress conditions. It is overexpressed in gliomas and supports tumor cell survival and resistance. Hsp90 inhibition can impact several pathways essential for glioma cell survival and overcome tumor heterogeneity. Here, we examined the activity and toxicity profile of MPT0B640, an orally bioavailable Hsp90 inhibitor, against gliomas and its ability to cross the blood-brain barrier (BBB).

METHODS
Using genetically heterogeneous glioma stem-like cell (GSC) lines, we determined the effects of MPT0B640 on cell proliferation (Cell Titre Glo assay), apoptosis induction and cell cycle changes (flowcytometry; AnnexinV/PI staining), and alterations in protein expressions (western blot and reverse-phase protein array, RPPA assays). Pharmacokinetic and pharmacodynamic (PK/PD) studies were performed in non-tumor bearing mice to assess BBB permeability and antitumor effects of MPT0B640.

RESULTS
MPT0B640 inhibited proliferation of both adherent (LN229, A172, U251-HF) and patient-derived GSCs (GSC262, GSC811, GSC11, GSC23, GSC20 and GSC272) in a dose- and time-dependent fashion with an IC50 range of 50-1000 nM. MPT0B640-treated cells underwent apoptosis and/or cell cycle arrest with downregulation of pro-survival signal kinases, phospho-Akt, p-ERK1/2 and p-S6. PK/PD studies showed increased HSP70 expression (a marker of Hsp90 inhibition) and detectable levels of drug in brain specimens from non-tumor bearing mice after a single dose of MPT0B640, indicating BBB permeability and target inhibition of the agent. Results of ongoing animal studies assessing drug toxicity and animal survival with MPT0B640 will be presented.

CONCLUSIONS
MPT0B640 is a potent HSP90 inhibitor that has potent antitumor activity against genetically heterogeneous gliomas in vitro, effectively crosses the intact BBB and demonstrates target inhibition warranting further investigation for treatment of gliomas.