bluuebunny/crossref_metadata_2025_split huggingface dataset:
EXTH-63. COMBINED INHIBITION OF TOP1 AND PARP: A NOVEL THERAPEUTIC STRATEGY FOR GBM WITH PTEN DEFICIENCY
Authors: Kim Olga , Butler Madison , Robey Robert , Chari Raj , Sergi Zach , Zhang Meili , Pang Ying , Yu Guangyang , Zhang Wei , Song Hua , Davis Dionne , Wang Herui , Merchant Mythili , Ranjan Alice , Gilbert Mark , Gottesman Michael , Pommier Yves , Wu Jing 
Published: November 2022

Abstract

BACKGROUND
Glioblastoma (GBM) is the most aggressive and lethal type of brain tumor. Activation of PI3K/mTOR pathway along with the loss of its primary negative regulator, phosphatase and tensin homolog (PTEN), occurs in nearly 50% of GBM patients. As PTEN is known to promote DNA damage repair deficiency, here we investigated whether PTEN deficiency presents a vulnerability to a simultaneous induction of DNA damage and suppression of repair mechanisms by combining topoisomerase I (TOP1) and PARP inhibitors.

METHODS
We used patient-derived GBM cells and stem-like cells to determine response to LMP400 (Indotecan), a novel non-camptothecin TOP1 inhibitor, and the PARP inhibitors Olaparib or Niraparib. Treatment efficacy was also determined using cell viability, cell cycle, DNA damage, repair, and apoptosis assays in a pair of isogenic PTEN-null and PTEN-WT glioma cell lines derived from a genetically engineered mouse GBM model. RNAseq analysis was performed to identify treatment-induced dysregulated pathways.

RESULTS
PTEN-deficient cells are highly sensitive to LMP400 and PTEN rescue lessens sensitivity to the treatment. Combining LMP400 with PARP inhibitors, Olaparib or Niraparib, leads to synergistic cytotoxicity. LMP400/Niraparib combination induces G2/M cell cycle arrest, DNA damage, suppression of homologous recombination (HR)-related proteins and activation of caspase 3/7 activity significantly more in PTEN-null cells compared to isogenic PTEN-WT cells. Gene set enrichment analysis revealed suppression of cell cycle and DNA damage repair as well as activation of cell death pathways. Finally, CRISPR-Cas9 KO screening suggests that LMP400 is not likely to be a substrate for ABC transporters, suggesting the brain penetration and supporting the use in brain tumor patients.

CONCLUSION
Combined inhibition of TOP1 and PARP induces synergistic antiglioma effects selectively in PTEN-null glioblastoma cells, providing a strong scientific premise for a clinical trial of combined treatment with LMP400 and Niraparib in a subset of GBM with PTEN deficiency.
EXTH-65. SYNERGISTIC ONCOLYTIC EFFECTS OF TEMOZOLOMIDE AND ONCOMAGNETIC THERAPIES IN GLIOBLASTOMA
Authors: Pandey Arvind , Hambarde Shashank , Baskin David , Helekar Santosh 
Published: November 2022

Abstract
The noninvasive Oncomagnetic device developed in our laboratory selectively kills glioblastoma (GBM) and other cancer cells while sparing normal developing neurons and astrocytes in vitro. We have reported that brief 2 – 6 h of daily Oncomagnetic brain stimulation causes &gt;30% reduction of contrast-enhanced tumor (CET) volume in an end-stage recurrent GBM patient after a ~30-day treatment. We have evidence that the spinning oscillating magnetic fields (sOMF) generated by this device disrupts electron transport in the mitochondrial respiratory chain, at least in part by inhibiting the activity of Complex II succinate dehydrogenase, leading to a marked increase in reactive oxygen species (ROS) and consequent cancer cell death. Here, we further studied the cellular effects of sOMF treatment alone and in combination with Temozolomide (TMZ) on GBM cell lines with other methods and investigated the response to Oncomagnetic monotherapy (OMT) in a mouse GBM model. We treated LN229 and U87 GBM cells with sOMF with and without a sub-therapeutic dose of TMZ. To study the anticancer effect of sOMF in vivo, we developed syngeneic GBM tumors in BALB/c mice by stereotactic intracranial injection of GL261WT cells. Our results show that cytotoxic effects of sOMF or TMZ alone, as measured by the MTT assay and reduced cell survival, are significantly potentiated by combining the two treatments. OMT of tumor-bearing mice using a whole-body sOMF stimulation method causes substantial retardation of tumor growth and reduction of the CET volume in 9.4 T MRI scans. To study the molecular pathways involved in the treatment response we are mapping alterations in various key biomarkers in treated tumor tissues and comparing them with those in untreated controls. These experiments will unravel the molecular mechanism of action underlying the response to OMT in GBM and help develop a sound rationale for an effective therapeutic protocol.
EXTH-70. IMMUNOTHERAPY REVERSES GLIOMA-DRIVEN DYSFUNCTION OF IMMUNE SYSTEM HOMEOSTASIS
Authors: Dean Bayli , Wildes Tyler , Dean Joseph , Shin David , Francis Connor , Sebastian Mathew , Font Laura Falceto , Moore Ginger , Wummer Brandon , Flores Catherine 
Published: November 2022

Abstract

BACKGROUND
Glioma-induced immune disfunction has been described in a limited number of studies, and here we further demonstrate that gliomas also interrupt the cellular differentiation programming and outcomes of hematopoietic stem cells (HSC) in the bone marrow. HSCs from glioma-bearing mice are re-programmed and driven towards expansion of myeloid lineage precursors myeloid-derived suppressor cells (MDSC) in secondary lymphoid organs. However, we found this is reversed by immunotherapy. Adoptive cellular therapy (ACT) has been demonstrably efficacious in multiple preclinical models of CNS malignancies, and here we describe how glioma-induced disfunction is reversed by this immunotherapeutic platform.

METHODS
The impact of orthotopic KR158B glioma on HSCs was evaluated in an unbiased fashion using single cell RNAseq of lineage- cells and phenotypically using flow cytometry. Mature myeloid cell frequencies and function were also evaluated using flow cytometry. Finally, ACT containing total body irradiation, tumor-specific dendritic cells, tumor-reactive T cells, and HSCs isolated from glioma-bearing or non-tumor-bearing mice was used to evaluate cell fate differentiation and survival.

RESULTS
We observed differential gene expression of HSCs in tumor-bearing versus healthy mice coupled with an expansion of myeloid lineage subsets in glioma-bearing mice. Interestingly, MDSCs from glioma-bearing mice demonstrated hyper suppressive capacity as compared to MDSCs from non-tumor-bearing hosts. Interestingly, treatment with ACT overcame the suppressive properties of glioma-bearing HSCs. When HSCs from tumor-bearing mice were transferred with ACT, we observed significant survival benefit and long-term cures in orthotopic glioma models compared with mice treated with ACT using non-glioma-bearing HSPCs.

CONCLUSIONS
These findings demonstrate the suppressive disposition in HSCs from glioma-bearing hosts can be redirected using ACT for significant survival benefit. Collectively, these data demonstrate gliomas impact the hematopoietic compartment at the progenitor level to promote expansion of suppressive myeloid cells and their progenitors. However, ACT can overcome this bias and provide lasting anti-tumor effects.
EXTH-75. INTEGRATED STRESS RESPONSE ACTIVATORS SYNERGISTICALLY INDUCE APOPTOSIS AND SUPPRESS PROLIFERATION IN DIFFUSE INTRINSIC PONTINE GLIOMA
Authors: Novak Orlandi , Arnold Antje , Eberhart Charles , Raabe Eric 
Published: November 2022

Abstract
DIPG has elevated baseline activation of the integrated stress response (ISR), an evolutionarily conserved system that enables cells to tolerate various forms of stress. Activation of the ISR is indicated by increased expression of activating transcription factor 4 (ATF4). Intermediate levels of ATF4 protect cells from stress, while persistent high levels result in cell death. The imipridone drug ONC201 increases mitochondrial stress and ATF4 expression by binding to and activating the mitochondrial protease ClpP. Sal003 inhibits dephosphorylation of ATF4 upstream regulator, eIF2α. The retinoic acid derivative fenretinide induces ATF4, increases reactive oxygen species, and has clinical activity in pediatric patients with neuroblastoma. Because DIPG has a high baseline level of ATF4, we hypothesized that the ISR activators Sal003, ONC201, and fenretinide would synergize to kill DIPG. After determining the IC50 of Sal003, fenretinide, and ONC201, we treated patient-derived DIPG cell lines with low micromolar doses. The combination of Sal003 and ONC201 significantly increased apoptosis as measured by CC3 immunofluorescence in comparison to DMSO and single treatment (p&lt; 0.0001, ANOVA). Western blots for cleaved PARP expression detected induction of apoptosis in DIPG treated with both Sal003 and ONC201 over DMSO and monotherapy treated cells. The combination also increased ATF4 expression. Since Sal003 is not clinically available, we treated DIPG cells with ONC201 and fenretinide. Synergy testing in JHH-DIPG1 showed an overall ZIP synergy score of 14 with inhibitory concentrations of both drugs in the nanomolar range. CC3 immunofluorescence indicated elevated apoptosis in the combination vs. DMSO (p&lt; 0.0001, ANOVA). Western blots showed increased cleaved PARP, ATF4, p-eIF2α, and CHOP expression in DIPG treated with ONC201 and fenretinide. We are currently testing the efficacy of this combination in brain organoids and orthotopic DIPG xenografts. Our results suggest the combination of ONC201 with fenretinide could potentially serve as a therapy for DIPG.
EXTH-82. THERAPEUTIC TARGETING OF EZH2 AND BET BRD4 IN PEDIATRIC RHABDOID TUMORS
Authors: Ishi Yukitomo , Zhang Yongzhan , Zhang Ali , Sasaki Takahiro , Piunti Andrea , Suri Amreena , Watanabe Jun , Abe Kouki , Natsumeda Manabu , Zou Lihua , Shilatifard Ali , Hashizume Rintaro 
Published: November 2022

Abstract

BACKGROUND
Aberrant activity of the H3K27 modifiers EZH2 and BRD4 is an important oncogenic driver for atypical teratoid/rhabdoid tumor (AT/RT), and each is potentially a possible therapeutic target for treating AT/RT. Thus, targeting distinct histone modifier activities would be an effective approach for treating AT/RT.

METHODS
The effects of EZH2 and BRD4 inhibition on histone modification, cell proliferation, and cell invasion were analyzed by immunoblotting, MTS assay, colony formation assay, and cell invasion assay. RNA- and chromatin immunoprecipitation-sequencing were used to determine transcriptional and epigenetic changes in AT/RT cells treated with EZH2 and BRD4 inhibitors. We treated mice bearing human AT/RT xenografts with EZH2 and BRD4 inhibitors. Intracranial tumor growth was monitored by bioluminescence imaging, and the therapeutic response was evaluated by animal survival.

RESULTS
AT/RT cells showed elevated levels of H3K27 trimethylation (H3K27me3) and H3K27 acetylation (H3K27ac), with expression of EZH2 and BRD4, and lack of SMARCB1 proteins. Targeted inhibition of EZH2 and BRD4 activities reduced cell proliferation and invasiveness of AT/RT in association with decreasing H3K27me3 and H3K27ac. Differential genomic occupancy of H3K27me3 and H3K27ac regulated specific gene expression in response to EZH2 and BRD4 inhibitions. Genes associated with DNA-repair pathway was downregulated upon EZH2 and BRD4 inhibition, and the sensitivity to cisplatin was elevated upon combination of EZH2 and BRD4 inhibitors in vitro. A combination of EZH2 and BRD4 inhibition increased the therapeutic benefit in vitro and in vivo, outperforming either monotherapy.

CONCLUSION
Histone H3K27me3 and H3K27ac were elevated in AT/RT cells and distributed in distinct chromatin regions to regulate specific gene expression and to promote AT/RT growth. Targeting EZH2 and BRD4 activity is therefore a potential combination therapy for AT/RT.
EXTH-90. HDAC INHIBITOR, CAY10603, IS A POTENT RADIOSENSITIZER IN MENINGIOMAS
Authors: Hanemann Clemens Oliver , Na Juri 
Published: November 2022

Abstract
Developing and evaluating potential radiosensitisers to enhance therapeutic efficacy are urgently needed due to the lack of efficient chemotherapy for meningioma. Histone deacetylase (HDACs) expression is generally increased in many cancer types and regulate the expression of numerous proteins involved in tumorigenesis. Targeting HDAC using HDAC inhibitor (HDACi) represent promising radiosensitisers that affect various biological processes, such as cell survival, apoptosis, and DNA repair. Recently, one of the HDAC inhibitor, AR42 monotherapy trials for patients with neurofibromatosis type2 started Nov 2021. However, we were not able to detect the actual HDAC downregulation after applying AR42 (0.5-2 μM) in immortalised meningioma. Hence, we investigated whether pretreatment with the hydroxamate-based HDAC6 inhibitor, Cay10603, impacts HDAC expression, radiation-induced DNA double-strand break (DSB) induction, cell survival, and cell cycle arrest in both immortalised and human meningioma cell lines. Cay10603 at nanomolar level (100 nM) was treated prior to high energy x-ray irradiation (2 Gy) by a medical linear accelerator (LINAC). We found that surviving rate was synergistically decreased after combination treatment of Cay10603 and radiation. Combination therapy induced DNA damage with activation of histone gH2AX and increased G2/M arrest compared to drug or radiation alone. To focus on the mechanisms of action of HDAC6 inhibition followed by radiation, we further investigated nuclear localisation of beta-catenin levels. The results showed the beta-catenin in the nucleus was suppressed after combination therapy. Our findings demonstrate a potential therapeutic strategy of Cay10603 to improve the radiosensitization for meningiomas.
EXTH-92. TARGETING PRIMARY CENTRAL NERVOUS SYSTEM B CELL LYMPHOMA IGH CLONOTYPES USING NOVEL RNA-NPS
Authors: Ogando-Rivas Elizabeth , Von Roemeling Christina , Castillo Paul , Liu Ruixuan , Mendez-Gomez Hector , Thomas Nagheme , Weidert Frances , Chardon-Robles Jonathan , Qdaisat Sadeem , Cascio Matthew , Ligon John , Huang Jianping , Mitchell Duane , Sayour Elias 
Published: November 2022

Abstract

BACKGROUND
Recurrent PCNSBLs represent a therapeutic challenge. Up to 60% of PCNSBL patients relapse to later face survival rates as low as 22%. Unfortunately, tumor heterogeneity and off-target effects have limited the success of immunotherapy against PCNSBL.

METHODS
We propose a novel immunotherapy to overcome PCNSBL heterogeneity and off-target effects in an exquisitely tumor specific manner using nanoparticle vaccination, capable of delivering personalized tumor derived mRNAs, that induces systemic orchestration of innate and adaptive immunity. We target tumor antigens derived from the B cell receptor (i.e., heavy chain immunoglobulin - IgH) clonotypes. IgH clonotypes are hypervariable gene rearrangements clonally generated by B cells. Tumor IgH clonotypes are unique for each malignant B cell clone and hence attractive immune targets, not shared by normal B cell clones avoiding undesirable off-target effects.

RESULTS
RNA-NPs can reprogram tumor microenvironment while activating the innate immunity via IFN type I (i.e., IFNα) and priming of hypervariable region clonotype specific T cell responses in naïve mice. We determined the rearranged IgH sequences (predominant clone 99% and nine additional clones with frequencies &lt; 1%) of clinically relevant inbred murine PCNSBL models (BAL17 and A20) by PCR. The number of identified clonotypes confirmed the IgH variability observed in human B cell hematological malignancies. In preliminary experiments targeting lymphoma derived single clonotypes with RNA-NPs, we showed the feasibility of priming in-vivo T cells specific against hypervariable regions after 3 weekly i.v. RNA-NPs (median IFNγ: 58 pg/ml; range: 50-70 pg/ml vs controls &lt; 30 pg/ml; p=0.008). Targeting of clonotype RNA-NPs was associated with decreased tumor growth (p=0.04). Interestingly, we have observed tumor reactive lymphangiogenesis that communicates with regional skull bone marrow observed in 3D microscopy that might direct future routes of RNA-NP administration.

CONCLUSION
Our RNA-NP systemic vaccination platform can induce PCNSBL clonotype specific T cell responses, sparing normal tissues.
EXTH-93. THE IRAK-4 INHIBITOR EMAVUSERTIB (CA-4948) FOR THE TREATMENT OF PRIMARY CNS LYMPHOMA
Authors: von Roemeling Christina , Doonan Bently , Klippel Kelena , Hoang-Minh Lan , Ogando-Rivas Elizabeth , Martinez Elizabeth , Castillo Paul , Iqbal Madiha , Tun Han , von Roemeling Reinhard , Mitchell Duane 
Published: November 2022

Abstract

BACKGROUND
PCNSL is an aggressive brain tumor accounting for 3% of all CNS malignancies and is associated with poor prognosis. Standard of care treatment includes induction with high-dose methotrexate based chemoimmunotherapy followed by consolidation with autologous stem cell transplant or whole brain radiation. However, more than half of PCNSL patients cannot tolerate this intensive therapeutic intervention. Novel treatments are urgently needed. Toll-like receptor signaling pathway via MyD88/IRAK-4 signalosome is constitutively active in PCNSL secondary to MYD88 L265P mutation and represents an excellent therapeutic target. Emavusertib (CA-4948) is an oral first-in-class small molecule inhibitor of IRAK-4 that demonstrates clinical activity in patients with systemic Non-Hodgkin’s Lymphoma, however it has not been evaluated in the CNS space. HYPOTHESIS: Emavusertib has anti-tumor activity against preclinical PCNSL.

METHODS
Using multiparameter immunohistochemistry (IHC) and proteomics analysis, IRAK-1, IRAK-4, and NF-κB pathway activation were examined in patient PCNSL tissues as compared to normal controls. Plasma, cerebrospinal fluid, and brain tissue were assessed via UPLC-MS/MS for emavusertib drug concentration following single oral high dose in a murine model. Survival responses in preclinical PCNSL models were measured in response emavusertib treatment, along with in vivo tumor proliferation and downstream biomarker expression by multi-parameter IHC.

RESULTS
Our data confirm elevated IRAK-1, IRAK-4, and NF-κB signaling in patient PCNSL. We show that emavusertib can achieve therapeutically relevant concentrations in the brain and CSF. Emavusertib impairs tumor cell proliferation in vitro and in vivo, and shows dose-dependent single-agent activity in preclinical PCNSL models. We confirm decreased ERK1/2, MAPK and NF-κB activation, indicative of downstream IRAK-4 inhibition.

CONCLUSIONS
Our data supports that emavusertib demonstrates anti-tumor activity in the CNS space, warranting further preclinical and clinical evaluation of this agent for the treatment of PCNSL.
EXTH-94. LOCALIZED INTRATUMORAL TREATMENT WITH ADOPTIVE T CELL THERAPY FOLLOWED BY ONCOLYTIC ADENOVIRUS DELTA-24-RGDOX INDUCES SUSTAINABLE REGRESSION OF DISSEMINATED SOLID TUMORS THROUGH ANTIGEN SPREAD
Authors: Jiang Hong , Shin Dong Ho , Yi Yanhua , Fan Xuejun , Gumin Joy , Gillard Andrew , Alonso Marta M , Lang Frederick , Gomez-Manzano Candelaria , Fueyo Juan 
Published: November 2022

Abstract
Tumor-targeting biological therapies, including adoptive T cell therapy (ACT) and oncolytic viruses, are being tested clinically to address the challenges in treating advanced solid tumors with heterogeneity and immune suppressive microenvironment (TME). Since complementary properties of these two approaches have been observed, we hypothesize that localized intratumoral treatment with combination of ACT and Delta-24-RGDOX (third generation oncolytic adenovirus developed by our group) induces not only potent therapeutic effect in treated tumor but also abscopal benefit to eliminate distant disseminated tumors. Using a B16-C57BL/6 melanoma model with disseminated tumors in C57BL/6 mice, we found gp100-specific CD8+ T cells injected into the first subcutaneous (s.c.) tumor showed tropism for distant s.c. and intracranial tumors, tumor draining lymph nodes, compared to spleen, blood and normal brain hemisphere. In a B16-OVA-C57BL/6 s.c./s.c. tumor model, Delta-24-RGDOX injections following gp100-specific T cells in the first tumor increased total cytotoxic T cell presence within both tumors, including gp100- and OVA- specific T cells. Further analysis revealed that Delta-24-RGDOX reduced the exhaustion of OVA-specific T cells while that of gp100-specific T cells kept at a low level. Moreover, Delta-24-RGDOX augmented the activity of the splenocytes against the tumor cells and other tumor-associated antigens (OVA, TRP2) than gp100. Consequentially, the combination of OVA-specific T cells and Delta-24-RGDOX was more potent to inhibit the injected and untreated distant tumor growth and caused improved survival rate than either of the agent alone (p &lt; 0.05). Importantly, we observed relapse of the regressed tumors in the T cell treatment group, but not in the combination group. The survivors developed immune memory against rechallenging with B16-OVA cells. Collectively, our data demonstrate that localized treatment with intratumoral ACT followed by Delta-24-RGDOX induces global immune activation and antigen spread to expand antitumor T cell repertoire, leading to efficacious systemic anti-tumor immunity and sustainable tumor regression.
EXTH-96. BIOPROCESSING OF SURGICAL PEDIATRIC BRAIN TUMOR SPECIMENS FOR GENOME-GUIDED PERSONALIZED DRUG TESTING
Authors: Nasajpour Emon , Lyle Geoff , Lancero Hope , Garcia Cesar , Learned Katrina , Gibson Eden , Tran Caitlynn , Schouten Troy , Vogel Hannes , Mahaney Kelly , Prolo Laura , Vaske Olena , Grant Gerald , Petritsch Claudia 
Published: November 2022

Abstract
Novel treatment approaches for pediatric central nervous system (CNS) tumors are urgently needed. A lack of patient-derived tumor cells impedes progress towards developing such new therapies. We intended to overcome this challenge by establishing methods to create a biorepository of viable single cell suspensions of pediatric brain tumor surgical specimens. Quantitative and qualitative comparisons of tissue processing strategies were performed to preserve viability of heterogeneous tumor and immune cells. Novel drug targets were identified by analyzing pathways affected by RNA transcripts that are highly expressed (outliers) in a patients’ tumor; outliers for each patient were determined by RNA-seq data from individual patients’ tumors compared with a compendium of 12,747 pediatric and adult samples harmonized by the Treehouse Childhood Cancer Initiative at the UCSC Genomics Institute. The predicted anti-tumor efficacy of small molecule inhibitors of the outlier pathways was tested in cell viability assays against short-term cultured cells from matched patients. Successful tissue collection required obtaining informed consent, standard operating procedures, and sample recording using a Laboratory Inventory Management Software (LIMS). Since 2020 we have banked 67 pediatric CNS brain tumor specimens at Stanford. Amongst those, 51 cases yielded sufficient tissue for RNA-seq and cryoprotection. The most common tumor histology was low-grade glioma (LGG, 26 of 67), the majority of which were pilocytic astrocytoma (18 of 26). The second and third most common tumor types are embryonal tumors (6 medulloblastoma, 3 AT/RT) and ependymoma (4), respectively. We identified significant differences in cell viability with different preservation media. An outlier pathway previously not implicated in LGG was identified and sensitivity to a small molecule inhibitor of this outlier pathway was demonstrated. Taken together, we established feasibility for validating therapeutic vulnerabilities identified by a genome-guided approach in short-term cultures from surgical specimens. This works facilitates the rapid development of personalized CNS tumor treatment.