bluuebunny/crossref_metadata_2025 huggingface dataset:
NCOG-16. A PROSPECTIVE OBSERVATIONAL STUDY OF CLINICAL PROFILE, COURSE AND OUTCOME OF PRIMARY BRAIN TUMOR AT A TERTIARY CARE CENTER
Authors: Patel Monik , patel Vivek , Parikh Ankita
Published: November 2024

Primary brain tumors include tumor arising from neuro-epithelial cells, cranial nerves, meninges, germ cells, pituitary gland, and blood-forming organs. These tumors can present with either generalized or focal signs and symptoms.General symptoms are due to raised intracranial pressure (headache, vomiting). Focal symptoms are due to the compression of a structure or destruction (focal neurological deficits). The aim of this study is to analyze the clinical profiles of pediatric and adult brain tumor patients. Data of primary brain tumor patients who were diagnosed from 1st December 2019 to December 2021 were prospectively collected and analysed. In our study of 61 patients, the majority of patients had GBM (32.8%) and astrocytoma (31.1%) and medulloblastoma (11.5%). Less common histologies ependymomas (9.8%), meningioma (6.6%), brain stem glioma (3.3%), oligodendrogliomas (3.3%) and germinoma (1.6%). Out of 19 astrocytomas, 10 were of low grade (1 or 2), while 9 were of high grade (3 or 4).The majority (61.7%) of gliomas were of high grade, while the remaining 38.3% were of low grade. The majority (57.5%) of patients received multimodal treatment,26.2%received dual modality (surgery and RT), while the remaining 16.3% received single modality, either surgery or RT. Most (86.9%) of the patients treated with radiotherapy as a part of a single or multimodal treatment. A significant percentage of patients (77.1%) received concurrent and adjuvant temozolamide-based chemotherapy. Primary brain tumors have a different profile in pediatric patients. Among pediatric patients, the median age was 11.8 years, with male predominance. This study concludes that primary brain tumors have a different profile among adults and pediatric patients, with the majority of patients achieving a response to the first line therapy with an overall good tolerance for therapy.
NCOG-26. THERAPEUTIC POTENTIAL OF FECAL MICROBIOME TRANSPLANT TO IMPROVE COGNITIVE DYSFUNCTION INDUCED BY CRANIAL IRRADIATION IN MICE
Authors: Bekal Mahesh , Das Tushar , Blasco-Conesa Maria P , Jagadeesan Gayathri , Ballester Leomar , Ganesh Bhanu Priya , Esquenazi Yoshua
Published: November 2024

Radiation therapy (RT) is a crucial treatment for brain tumors, but radiation-induced cognitive dysfunction (RICD) affects 50-90% of patients, significantly impacting their quality of life. Evidence suggests that gut microbiome dysfunction may contribute to progressive cognitive dysfunction (CD). Prior studies in aging and stroke models show that fecal microbiome transplants (FMT) from healthy hosts can promote recovery and improve cognition. To investigate the link between RICD and the gut microbiome, we subjected mice to Sham/9Gy/15Gy cranial irradiation, followed by cognitive tests using the Y-maze and Novel Object Recognition Test (NORT) at various time points. Both 9Gy and 15Gy irradiation resulted in significant cognitive dysfunction, as indicated by altered performance in both tests at 7 and 30 days post-irradiation. Fecal samples were collected before irradiation and at 10 and 30 days post-RT. Microbial DNA was extracted, and the 16S rRNA gene was sequenced and analyzed using the bioinformatics visualization toolkit, ATIMA. Significant gut dysbiosis was observed in both 9Gy and 15Gy irradiated mice compared to pre-irradiation samples, with the 15Gy group showing more pronounced and consistent changes in fecal microbiome diversity, particularly at 30 days post-RT. We hypothesized that FMT from healthy hosts (non-radiated mice) could prevent or ameliorate RICD by modulating microbial, metabolomic, and immunologic profiles. To test this, a separate cohort of mice received 15Gy cranial irradiation and FMT via oral gavage. After a 20-day post-irradiation period, cognitive and gut permeability tests were conducted. The FMT group exhibited significantly improved gut permeability and cognitive performance compared to controls. Our findings suggest that gut dysbiosis plays a crucial role in RICD and that FMT may be a potential strategy to mitigate RICD and improve the quality of life in brain tumor patients undergoing cranial RT.
NCOG-38. LAMOTRIGINE MONOTHERAPY ASSOCIATES WITH IMPROVED PROGRESSION-FREE AND OVERALL SURVIVAL IN HIGH-GRADE GLIOMA
Authors: Rilinger Ryan , Sharma Akshay , Feldman Marina , Guo Lydia , Volovetz Josephine , Grabowski Matthew , Lobbous Mina
Published: November 2024

BACKGROUND

High-grade gliomas (HGG) are aggressive brain tumors with notoriously poor prognoses and high symptomatic burden, including seizures in 30-60% of HGG cases. Despite negative impacts to quality of life, positive seizure history at presentation and during the disease course has been shown to associate with improved overall survival. Further, recent preclinical studies have suggested a link between neuronal hyperexcitation and more rapid glioma progression. We hypothesized anti-seizure medication (ASM) therapy may suppress neuronal excitation and therefore help prolong survival. To this aim, we characterized the association of various ASM therapies with survival and seizure control.

METHODS

Retrospective review of 413 patients with co-occurring HGG and clinically diagnosed epileptic activity. Multivariable linear regression was used to assess the impact of ASM quantity (monotherapy versus polytherapy) and type (specific ASMs as well as ASM class) on progression-free survival (PFS) and overall survival (OS). Logistic regression was used to assess the impact of ASM quantity and type on likelihood of achieving seizure remission. Additional variables in the regressions included age, treatment exposure (radiation therapy, cytotoxic chemotherapy, or targeted chemotherapy), and extent of surgical resection (gross total resection versus all other surgeries). Kruskal-Wallis tests were used to compare median survival between multiple groups.

RESULTS

ASM monotherapy and polytherapy demonstrated comparable survival outcomes. Among patients who received ASM monotherapy, only lamotrigine demonstrated a significant association with improved survival with PFS and OS (P = <0.001 for both). No specific drug or drug class demonstrated greater likelihood of achieving seizure remission.

CONCLUSION

Lamotrigine demonstrates a unique association with improved outcomes that is neither shared by other ASMs nor explained by ASM drug class, without any decline in likelihood of achieving seizure remission. Optimization of ASM therapy may enhance survival outcomes without compromising seizure control.
EXTH-03. CAR T-CELLS TARGETED TO B7-H3 OR HER2 FUNCTION INDEPENDENTLY OF ANTIGEN DENSITY IN XENOGRAFT MODELS OF EPENDYMOMA
Authors: Mehta Sanya , Ibanez Jorge , Houke Haley , Ippagunta Siri , Emanus Erik , Mack Stephen , Krenciute Giedre
Published: November 2024

BACKGROUND

Targeted treatment options are desperately needed for ependymomas (EPN). Chimeric antigen receptor (CAR) T-cells have immense potential to positively transform treatment outcomes; however, little is known regarding antitumor efficacy of CAR T-cells against EPNs. Specifically, antigen density has emerged as a major influencer of CAR T-cell potency. However, the specific high and low antigen density thresholds governing CAR T-cell efficacy for EPN are unknown. The goal of this project is to determine the role of antigen density in CAR T-cell potency against EPN.

METHODS

Using quantitative flow cytometry, we determined antigen density of B7-H3 and HER2 (the two CAR targets currently in pediatric EPN clinical trials), on EPN patient derived cell lines (1425, ST1, CPITT, ST2, EPI, L46SJ). We generated B7-H3 and HER2-CAR T-cells with CD28z signaling domain and compared long-term cytolytic activity, expansion, and cytokine production against EPNs.

RESULTS

We found that all EPN cell lines express remarkably high yet variable density of B7-H3 (62,700 – 335,440 molecules/ cell). In contrast, surface density of HER2 was consistently and significantly lower (860 – 24,488 molecules/ cell). In repeated-stimulation assays, B7-H3-CAR T-cells killed 7-10 times and expanded up to 325,360-fold when cultured against EPN. However, we observed no significant difference in total expansion or correlation with antigen density against EPNs. Surprisingly, expansion of HER2-CAR T-cells against EPNs was drastically higher and greatly exceeded that of B7-H3-CAR-T cells against the same EPN cells despite much lower antigen density.

CONCLUSIONS

Our work shows that both B7-H3 and HER2 are good targets against EPN, despite drastic differences in antigen density. Results suggest that lower antigen density of HER2 may be superior for CAR T-cell activity. Future work will validate whether HER-CAR T-cells have superior antitumor efficacy in vivo to further delineate role of antigen density thresholds in CAR T-cell potency.
EXTH-18. ADAPTER CHIMERIC ANTIGEN RECEPTOR T CELL THERAPY TARGETING SSTR2 IN MENINGIOMA
Authors: Chen Jiawei , Pellegrino Christian , Mastall Maximilian , Szulzewsky Frank , Bijnen Mitchell , Van Hove Hannah , Favalli Nicholas , Bassi Gabriele , Moisoiu Vlad , Vasella Flavio , Padevit Luis , Neidert Marian , Cimino Patrick , Reimann Regina , Roth Patrick , Manz Markus , Greter Melanie , Holland Eric , Neri Dario , Weller Michael , Wirsching Hans-Georg
Published: November 2024

Effective treatment options for meningioma patients beyond surgical resection and radiotherapy are limited. This study presents preclinical and translational evidence supporting the efficacy of an adaptor CAR-T cell system targeting Somatostatin Receptor (SSTR) 2 in otherwise untreatable meningiomas. Tissue microarray analysis revealed that SSTR2 expression was generally heterogeneous but high or intermediate in most World Health Organization (WHO) grade 2 (87.8%) and grade 3 (87.5%) meningiomas. The fluorescein-linked, SSTR2 antagonist peptide octofluo was used in conjunction with adaptor FITC (AdFITC) CAR-T cells to treat experimental meningiomas. In vitro, 10 nM octofluo induced tumor cell killing within 72 hours at effector-target cell ratios (E:T) as low as 1:100. This was observed in two human meningioma cell lines, Ben-Men-1 (CAR-T cells vs. untransduced T-cells [UTT]: 47.9% vs. 4.7%, P < 0.001) and IOMM-Lee (CAR-T cells vs. UTT: 40.2% vs. 4.9%, P < 0.001). In vivo, the AdFITC CAR-T cell system inhibited meningioma growth (P = 0.002) and prolonged survival (P = 0.003) in the IOMM-Lee orthotopic model compared to PBS. In a genetically engineered murine meningioma model, the AdFITC CAR-T cell system not only restricted tumor growth (P = 0.0018) and improved survival (P < 0.0001), but cured a substantial proportion of meningioma bearing mice. This treatment also induced the expansion of both CD8+ CAR-T cells (P = 0.0041) and a host T-cell response. Preliminary ex vivo killing assays, involving co-culture of the AdFITC CAR-T cell system with patient-derived meningioma tissue, showed specific lysis rates of 15-20% (ET 1:1) within 12 hours. Targeting SSTR2 with the AdFITC CAR-T cell system emerges as a promising therapeutic approach for meningioma, an early phase clinical trial is warranted.
EXTH-23. NEW DNA-CROSSLINKING CHEMOTHERAPY IS EFFECTIVE AGAINST POST-TEMOZOLOMIDE MISMATCH REPAIR-DEFICIENT PATIENT-DERIVED HYPERMUTANT GLIOMAS
Authors: McCord Matthew , Wang Wenxia , An Shejuan , Sears Thomas , Sarkaria Jann N , James C David , Ruggieri Bruce , Bindra Ranjit S , Horbinski Craig
Published: November 2024

The DNA mismatch repair (MMR) pathway triggers glioblastoma (GBM) apoptosis when base mismatches induced by the alkylating agent temozolomide (TMZ) cannot be repaired. GBMs often develop hypermutation and resistance to TMZ through acquired inactivation of DNA MMR enzymes (MSH2, MSH6, MLH1, PMS2). A newly developed therapeutic, KL-50, fluoro-ethylates DNA bases, leading to DNA inter-strand cross-links. This form of DNA damage triggers MMR-independent apoptosis. Thus, KL-50 can target MMR-deficient tumor cells. Previous work showed that KL-50 is effective against GBM cell lines that were rendered TMZ-resistant through shRNA knockdown of MMR genes (PMID 35901163). In those studies, KL-50 was most effective when used in combination with an MGMT enzyme inhibitor, or in MGMT-deficient cells. Here, we extend those findings with a preclinical trial of KL-50 in GBM patient-derived xenografts (PDX), including PDX models of post-TMZ GBM that acquired MMR mutations and hypermutation through serial TMZ exposure (PMID 31852831). Among TMZ-naïve PDX, KL-50 extended survival of engrafted mice by 24 days for GBM6 (partially MGMT-deficient), and by 38 days for GBM12 PDX (fully MGMT-deficient) compared to vehicle (p<0.0001, Log-Rank). Combining KL-50 with 4.0 Gy radiation further extended survival of GBM12 mice (9 days, p=0.02), but not GBM6 mice. With engraftments of GBM6R-m185, a post-TMZ, MMR-deficient derivative of GBM6, 14/14 (100%) of KL-50 treated mice are still alive 60 days post-engraftment compared to 0/13 (0%) of vehicle control mice (median survival 37 days, p<0.0001, experiment ongoing). Complementary in vitro studies showed that GBM6R-m185 cells are more sensitive to KL-50 than TMZ at matched concentrations of 50µM (p=0.001, one-way ANOVA) and 100µM (p=0.047). These data demonstrate the potential of KL-50 in treating post-TMZ MMR-deficient recurrent gliomas.
EXTH-26. EXPLORING THE ROLE OF ANDROGEN RECEPTOR SIGNALING IN GLIOBLASTOMA IN AN ORTHOTOPIC ANIMAL MODEL
Authors: Mason Sofia R E , Chung Sylvia , Satgunaseelan Laveniya , McCool Cerys , Juan Beatriz Perez-San , Gupta Shabarni , Zaman Ashraf , Day Bryan W , Dear Rachel , Sim Hao-Wen , Holst Jeff , Chaffer Christine L
Published: November 2024

OBJECTIVE

Gliomas, particularly glioblastoma which is the most common and deadly type, frequently express androgen receptors (AR). We systematically characterized AR expression in low- and high-grade gliomas to investigate whether disrupting AR signaling with readily available blood-brain-barrier penetrant drugs could improve treatment.

METHODS

Low- and high-grade glioma samples were stained for AR by immunohistochemistry, with AR-expression correlated to grade and sex. Localization of AR and the influence of dihydrotestosterone (DHT) and anti-androgens in glioblastoma cell line (U251) were determined by immunofluorescence and immunoblot. Building on previous in vitro data, we used an orthotopic AR-positive patient-derived model (RN1) to test the efficacy of seviteronel, a blood-brain-barrier penetrant anti-androgen.

RESULTS

Two thirds of biopsy samples were positive for AR expression by IHC (n=25/39). AR expression correlated with increasing tumor grade (p<0.05) but was similar between sexes (p=0.94). Anti-androgens enzalutamide and seviteronel prevented DHT-induced nuclear translocation of AR; however, seviteronel did so to a lesser extent, as measured by immunofluorescence and immunoblot. In the mouse model, seviteronel significantly improved survival compared to vehicle (n=12, 36.0 vs 27.5 days, p=0.03), and demonstrated reduced Ki67 expression in tumors at the endpoint (68.9% vs 85.0%, p<0.001). Combining seviteronel with temozolomide limited tumor growth as measured by bioluminescence imaging, but did not significantly extend survival compared to temozolomide alone (n=16, 63.5 vs 56.5 days, p=0.37). Adding seviteronel to radiotherapy did not extend survival compared to radiotherapy alone (n=16, 33.0 vs 39.0 days, p=0.19).

CONCLUSIONS

Targeting AR signaling with blood-brain-barrier penetrant anti-androgens may represent a promising biomarker-directed therapeutic strategy. The mechanisms underlying the effects of seviteronel are being further investigated through affinity-purification mass spectrometry analysis and CUT&RUN sequencing of untreated and treated glioma cells. Additional animal experiments are underway to examine the role of biological sex and the glioma immune microenvironment on the efficacy of anti-androgens in vivo.
EXTH-29. EVALUATION OF THE ANTITUMOR EFFECT OF A CHEMOTHERAPY-LOADED DEVICE FOR THE TREATMENT OF PRIMARY BRAIN TUMORS
Authors: Déry Laurence , Charest Gabriel , Guérin Brigitte , Akbari Mohsen , Fortin David
Published: November 2024

Glioblastoma (GBM) is the most frequent and aggressive primary brain tumor in adults. Tumor recurrence is therefore inevitable, and median survival is just over 14 months. Currently available treatments are inadequate and do not provide optimal tumor control. We believe that treatment localized directly at the tumor site will eliminate a greater number of infiltrating tumor cells while significantly reducing systemic toxicity. For this project, we are collaborating with a team specializing in bioengineering, who have produced a biomaterial enabling the gradual release of various chemotherapeutic agents. Our aim is to use this biomaterial to deliver chemotherapeutic agents to the tumor site through the surgical cavity. Cell-based assays were carried out using glial tumor cells in the presence of the biomaterial containing chemotherapeutics. A survival study was realized with the Fischer F98 rat model, which underwent partial tumor resection followed by injection of biomaterial containing chemotherapy. Histological studies of brains and resected tissues were also carried out to assess the effect of the biomaterial on the brain environment. In vitro assays showed a strong cytotoxic effect against glial tumor cells at 24h, 48h and 72h of biomaterial-drug incubation. The combination of two chemotherapeutic agents showed the best cytotoxic effect on glial tumor cells. We also performed a partial tumor resection and insertion of the chemotherapy-loaded biomaterial into the surgical cavity of the F98 glioma bearing rat. Similar to in vitro studies, the combination of two antineoplastic agents shows a significant improvement in animal survival. In conclusion, the in vitro and in vivo results of this study show that the combination of chemotherapy has the greatest antitumor effect. We hope that these exciting results will lead to the development of a new treatment for patients with glioblastoma and potentially other diseases where complete tumor resection is impossible.
EXTH-37. ALLOSTERIC MITOCHONDRIAL CLPP AGONIST ONC206 ALTERS STRESS RESPONSE, METABOLIC AND EPIGENETIC PROFILES TO ELICIT ANTI-CANCER EFFICACY IN HIGH-GRADE GLIOMAS
Authors: Prabhu Varun V , Maranto Cristina , Lee Andrew , Foster Scott , Allen Joshua E
Published: November 2024

Dordaviprone (ONC201) is a dopamine receptor D2/3 (DRD2/3) antagonist and allosteric ClpP agonist that has demonstrated durable responses in recurrent H3 K27M-mutant glioma patients. ONC206, a derivative of ONC201 with nanomolar potency that also targets DRD2/3 and ClpP, is in Phase I trials for central nervous system tumors. We characterized target relevance, human ClpP binding, in vitro efficacy, downstream signaling and response determinants associated with ONC206 in high-grade gliomas (HGG). Co-crystallization with ClpP that assembles as a tetradecameric complex revealed an allosteric ligand interaction with distinctions in the ONC206-ClpP overall conformation relative to the ONC201-bound or apo complex, including an increase in the resolved pore size and decreased complex height. ONC206 was more potent than ONC201 in cell-free human ClpP casein/peptide degradation assays). Accordingly, HGG cell lines and patient-derived cells exhibited increased sensitivity to ONC206 relative to ONC201 and generally required a shorter duration of exposure. Unlike DRD2, CRISPR-mediated ClpP knockout in HGG cell lines blunted ONC206 sensitivity. Metabolomics revealed elevated α-ketoglutaric acid, α-hydroxyglutaric acid, and glutaric acid. Proteomics indicated inhibition of multiple mitochondrial pathways including OXPHOS and TCA cycle. TCA cycle enzyme α-ketoglutarate dehydrogenase (KGDH) was inhibited in a ClpP-dependent manner. Western blotting showed downregulated ClpX, and upregulated ATF4/CHOP, H3 K27me3 and H3 K36me3. Next-generation sequencing of acquired resistance cell lines, which exhibited cross-resistance to ONC201 and ONC206, revealed diverse ClpP missense mutations distributed across various monomer interfaces. Both intrinsic and well as ONC206-stimulated ClpP proteolysis were mitigated by these mutations, which was congruent with an absence of the tetradecameric assembly. These ClpP mutations recapitulated resistance and, conversely, wildtype ClpP overexpression restored sensitivity. Thus, allosteric ClpP agonism is a key determinant of ONC206 activity in HGG by altering stress response, metabolic, and epigenetic profiles.
EXTH-38. EVALUATION OF STORAGE CONDITIONS ON SERUM-DERIVED EXTRACELLULAR VESICLES IN BRAIN TUMOR SAMPLES
Authors: Goel Pallavi , Kumari Neha , Kaur Inderjeet , Ghanekar Yashoda , Sadasivam Subhashini , Pawar Vikas , Madiraju Surya , Ray Amit
Published: November 2024

Tumor-derived Extracellular Vesicles (EVs) are emerging as potential liquid biopsy tool in the field of cancer diagnosis and therapeutic targets. The functionality of EVs depends on its diverse cargo, which is known to alter host-receipient cells. Nevertheless, extracting EVs while preserving its integrity and functionality of its contents is challenging, specifically in Low-middle Income countries (LMIC) countries. Our study focussed on extraction of serum derived EVs analysis from brain-tumor samples encompassing Oligodendrogliomas, Astrocytomas and Glioblastomas. The stability of EVs were examined in serum stored for 2 years at -80°C to understand the effect of preservation and storage in different conditions, that were left exposed to room temperature for variable periods of time before freezing. To explore the optimal suitable conditions, EVs were isolated from serum samples using IZON column size-exclusion based-method, and evaluated for structural integrity and stability through nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM) technology. Interestingly, the majority of isolated vesicles exhibited round, intact structure with bilayer membrane of size varying between 30 - 250nm. Moreover, protein content of EVs positive markers (CD63, CD81 and CD9) was also detected with minimal contaminations evidenced by weak bands for negative marker (ApoB), as determined by Western blot analysis. Further, column-based EV-derived RNA demonstrated optimal yield and purity was confirmed by RNA integrity number (RIN) using Qubit. While cryopreservation had minimum detrimental effects on mRNA sample quality, leaving it exposed to room temperature before freezing had a significant effect on EV isolation, as samples were often haemolyzed. This will provide insights in optimizing pre-analytical and analytical procedures for more effective outcomes in the clinical setting
EXTH-40. IMMUNOPHENOTYPING OF RWTC-MBTA AUTOLOGOUS CANCER VACCINE IN PRECLINICAL GLIOBLASTOMA MODELS
Authors: Wang Herui , Ye Juan , Medina Rogelio , Zhang Yaping , Chakraborty Samik , Uher Ondrej , Vanova Katerina Hadrava , Zenka Jan , Pacak Karel , Zhuang Zhengping
Published: November 2024

Despite advances in immunotherapy, glioblastoma multiforme (GBM) remains challenging to treat due to its low inherent immunogenicity and a suppressive tumor microenvironment. Converting “cold” GBMs to “hot” tumors is crucial for effective immune activation and improved patient outcomes. We comprehensively characterized the rWTC-MBTA autologous cancer vaccine, consisting of Mannan-BAM-anchored irradiated whole tumor cells, Toll-like receptor ligands (LTA, Poly(I:C), R-848), and an anti-CD40 agonistic antibody, in preclinical GL261 and SB28 GBM models. A substantial number of vaccinated mice exhibited complete regression of GBM tumors in a T-cell-dependent manner, with no significant toxicity. Long-term tumor-specific immune memory was confirmed upon tumor rechallenge. In the vaccine-draining lymph nodes of the SB28 model, rWTC-MBTA vaccination triggered a major rise in cDC1 12 hours post-treatment, followed by an increase in cDC2, moDC, and pDC on Days 5 and 13. Enhanced cytotoxicity of CD4+ and CD8+ T cells in vaccinated mice was verified in co-culture with tumor cells. Comprehensive immunophenotyping in the GL261 and SB28 GBM microenvironments confirmed decreased regulatory T cells and increased CD4+ and CD8+ T cell infiltration in vaccinated mice. T-cell exhaustion analyses revealed an increase in the Tim3+CD8+ T cells. No significant differences were observed in the quantification of M-MDSC and PMN-MDSC between control and vaccinated mice, but PD-L1 expression significantly increased in M2 macrophages in vaccinated mice. Our findings demonstrate that rWTC-MBTA induces potent and long-term adaptive immune responses against GBM, warranting further investigation of combinations with other immunotherapies for enhanced efficacy.
EXTH-41. COMBINATION TREATMENT WITH RAF/MEK AND FAK INHIBITION ENHANCES TUMOR GROWTH INHIBITION IN MENINGIOMA
Authors: Ijad Nazanin , Waller Katie L , Yamazawa Erika , Nayyar Naema , Summers Elizabeth J , Migliarese Christian , Galanis Evanthia , Carlson Brett L , Sarkaria Jann N , Wakimoto Hiroaki , Vaubel Rachael A , Brastianos Priscilla K
Published: November 2024

BACKGROUND

Patients with meningiomas who have progressed after multimodal treatments face a significant shortage of viable therapeutic options. Recent advancements in the molecular understanding of meningiomas have identified the FAK and RAF/MEK signaling pathways as potential promising targets for progressive meningiomas.

METHODS

In vitro, we tested two human meningioma cell lines, IOMM-Lee (NF2 wild-type and CDKN2A loss) and CH157-MN (NF2 mutant). The cells were plated in Matrigel-coated wells, treated with defactinib (FAK inhibitor), VS-6766 (RAF/MEK inhibitor, avutometinib) and the combination over a 7-day period and assessed for cell viability using the CellTiter-Glo 3D assay. In vivo, we tested the efficacy of the FAK inhibitor VS-4718 (possessing favorable pharmacokinetic properties in mice) and RAF/MEK inhibitor VS-6766, both given daily via oral gavage, in athymic nude mice bearing IOMM-Lee or CH157-MN tumors.

RESULTS

In the matrigel assay, VS-6766 suppressed IOMM-Lee and CH157-MN cells in a dose dependent manner. The drug combination was mostly additive in IOMM-Lee cells. However, CH157-MN cells showed a strong synergistic response across all drug concentrations tested. In the IOMM-Lee flank tumor model, VS-4718 alone had no effect, while VS-6766 alone or in combination significantly reduced tumor growth and extended median survival from 25 days to 47 days (p < 0.05). In the CH157 flank tumor model, VS-4718 monotherapy did not affect tumor growth or survival, but VS-6766 monotherapy slowed tumor growth and increased median survival from 10 days to 31 days (p < 0.001). Combining both drugs further reduced tumor growth and extended median survival to 42 days (p < 0.001).

CONCLUSION

Treatment with FAK and RAF/MEK inhibitors showed synergistic or combination effects in the NF2 mutant CH157-MN model in vitro and in vivo. RAF/MEK inhibitor monotherapy was effective for the IOMM-Lee model (NF2 wild-type), without clear benefit of combining with the FAK inhibitor. Investigations in intracranial tumor models are underway.
EXTH-43. ANTI-GLIOMA ACTIVITY OF BIMODAL CGAS-AGONISTIC AND STAT3-INHIBITORY SPHERICAL NUCLEIC ACIDS
Authors: Mahajan Akanksha , Dussold Corey , Kim Seunghyun , Jarvis Rachel , Tommasini Serena , Forsyth Connor , Hurley Lisa , Mirkin Chad , Stegh Alexander
Published: November 2024

Activation of the cGAS-STING (cyclic GMP-AMP synthase-stimulator of Interferon Genes) pathway enhances T cell activation and infiltration into tumors, reversing the immunosuppressive phenotype of myeloid cells. Targeting the STING receptor with synthetic cyclic dinucleotide (CDN) ligands offers a promising immunotherapeutic strategy for lymphocyte-depleted, myeloid cell-enriched tumors like Glioblastoma (GBM). However, this approach is constrained by the structural instability of CDNs and the presence of immune-evasive, STING-inhibitory mechanisms in the tumor microenvironment (TME), particularly those driven by the master transcriptional regulator STAT3 (Signal Transducer and Activator of Transcription 3). To activate cGAS anti-tumor responses and simultaneously inhibit STAT3-driven immunosuppression in the GBM TME, we developed Spherical Nucleic Acids (SNAs) consisting of a nanoparticle core densely functionalized with radially oriented stem-loop dsDNA oligonucleotides containing a guanine repeat element flanked by palindromic STAT3 decoy sequences. In vitro studies demonstrated that these SNAs effectively activate cGAS and inhibit STAT3 in reporter cell lines, exhibit high-affinity binding to both the cGAS enzyme and STAT3 proteins, and downregulate IL-6-induced STAT3 transcriptional targets. Furthermore, intratumoral injection of these bimodal SNA architectures induced type I interferon (IFN) and proinflammatory cytokines, activated T cells and B cells, and natural killer cells; and reprogrammed immunosuppressive tumor-associated macrophages (TAMs). Importantly, bimodal SNAs showed profound sex-based differential pharmacological action with therapeutic benefits seen in females but not in male mice in aggressive immune checkpoint-resistant murine glioma models. In the absence of cGAS transcriptional changes, western blot and flow cytometry analysis revealed that cGAS protein levels were approximately twice as high in female BMDMs (bone marrow-derived macrophages) and TAMs than males. In summary, our study establishes bimodal SNAs as a first-in-class, single-entity nucleic acid therapeutic capable of targeting multiple pathways for the immunological reprogramming of the GBM TME.
EXTH-44. ENHANCING THERAPEUTIC APPROACHES IN HIGH-GRADE GLIOMAS: SYNERGISTIC EFFECTS OF LSD1 AND KINASE INHIBITION
Authors: Stitzlein Lea M , Hernandez Faith A , Nam Deokhwa , Patel Kareena , Impelman Katie , Poche Alaina L , Su Xiaoping , Gumin Joy , Sareddy Gangadhara R , Lang Frederick F , Chandra Joya
Published: November 2024

BACKGROUND

Glioblastoma (GBM) and Diffuse Intrinsic Pontine Glioma (DIPG) are devastating high-grade gliomas (HGGs) with poor prognoses. Lysine-specific demethylase 1 (LSD1) is a promising therapeutic target and a key regulator in tumor initiation and recurrence. Crosstalk between LSD1 and other signaling pathways, such as the MAPK pathway, frequently hyperactivated in HGG, offers an opportunity to enhance the efficacy of LSD1 inhibitors. This study investigates the combined inhibition of LSD1 and kinase signaling to improve therapeutic outcomes in HGG.

METHODS

Transcriptional changes following LSD1 knockdown in human GBM cells were analyzed using RNA-seq and GSEA. RPPA and western blotting assessed the impact of LSD1 inhibition on kinase signaling. Pharmacological LSD1 inhibition was tested using NCD38 or bomedemstat in HGG models and normal human astrocytes (NHA). The effects of combining LSD1 inhibitors with kinase inhibitors (osimertinib, afatinib, and ulixertinib) on cell viability were evaluated. Combination treatment was also assessed in orthotopic xenograft models of GBM.

RESULTS

GSEA revealed LSD1 expression was enriched for gene sets involved in kinase signaling processes. Increased phosphorylated ERK1/2 levels were observed following NCD38 treatment in MDA-GSC17, as shown by RPPA and western blot analyses. The LSD1 inhibitor, NCD38, increased phospho-ERK1/2 levels (72% increase from baseline), while co-treatment with osimertinib mitigated this effect. Combined LSD1 and kinase inhibition (EGFR and ERK inhibition) showed synergistic effects in vitro in GBM and DIPG models but not in the NHA.

DISCUSSION

Our results demonstrate that kinase activity can be modulated by inhibiting LSD1, potentially leading to a resistant subpopulation. This study underscores the potential of combining LSD1 and kinase inhibition to enhance therapeutic efficacy in HGG, including GBM and DIPG. Future research will focus on elucidating the mechanisms by which LSD1 regulates kinase signaling, aiming to optimize combination therapies.
EXTH-47. ENHANCING GD2.CART THERAPY FOR DIFFUSE MIDLINE GLIOMA WITH LSD1 AND HDAC INHIBITORS
Authors: Murdaugh Rebecca , Shekar Meghan , Eberl Brittany , Tremblay Jack , Richard Rosemary , Harmanci Akdes Serin , Omer Bilal , Anastas Jamie
Published: November 2024

Chimeric antigen receptor T cells against the glycolipid GD2 (GD2.CARTs) are showing promise in diffuse midline glioma (DMG) but are not yet curative. Since low target antigen expression is one potential mechanism by which tumor cells can escape CART therapy, we profiled GD2 expression levels on 9 different H3K27M-mutant DMG cell lines using flow cytometry. This analysis shows that only 5 of the 9 cell lines exhibit high GD2 expression while the remaining 4 lines have low GD2-expressing cells. When treating these cell lines with GD2.CARTs in co-culture assays and xenograft mice, we find that low GD2 expression on DMG cells correlates with tumor cell escape from GD2.CARTs and therapeutic resistance in vivo. Our lab previously found that simultaneous inhibition of histone deacetylases (HDACs) and lysine-demethylase 1 (LSD1) in DMG cells causes synergistic increases in gene expression and tumor cell death. Previous studies in neuroblastoma also demonstrate that HDAC inhibitor (HDACi) treatment can increase GD2 on tumor cells and improve targeting by GD2.CARTs. We therefore decided to assess whether treating GD2-low DMG cell lines with combinations of LSD1 inhibitors (LSD1i) and HDACi improves DMG response to GD2.CARTs. Immunofluorescence and flow cytometric analyses show that GD2 expression is increased on LSD1i+HDACi-treated GD2-low DMG cells and that there is enhanced tumor cell targeting by GD2.CARTs in subsequent co-culture assays. Treating mice transplanted with GD2-low DMG cells with LSD1i+HDACi followed by intravenous GD2.CART infusion also led to reduced tumor growth. These results suggest that LSD1i+HDACi pre-treatment may provide a way to improve DMG patient responses to GD2.CART therapy by increasing target antigen expression.
EXTH-53. THE PHARMACOLOGICAL ATLAS OF MENINGIOMAS
Authors: Jungwirth Gerhard , Pan Yimin , Nalcakan Derin , Warta Rolf , Abdollahi Amir , Unterberg Andreas , Krieg Sandro , Herold-Mende Christel
Published: November 2024

No systemic treatment options exist for recurrent or refractory meningioma patients. This study aimed to create a pharmacological atlas of all FDA-approved oncology drugs in a large cohort of patient-derived meningioma organoids (TOs). TOs were generated from single cell suspensions from freshly resected meningiomas and were treated with semi-logarithmic concentrations spanning from 10 nM to 30 µM by the automated liquid handler Hamilton MicroLAB STAR®. The drug library AODX from the National Cancer Institute consisted of 179 FDA-approved anticancer drugs. The viability was measured with the RealTimeGlo (Promega). Half-maximal inhibitory concentrations (IC50) were calculated by GraphPad Prism software. We created a pharmacological atlas of meningiomas by generating 8,413 dose-response curves of 179 current FDA-approved oncology drugs in patient-derived tumor organoids from 47 meningioma patients. The cohort consisted of 35 grade 1, 11 grade 2, and 1 grade 3 meningiomas, including 10 recurrent tumors. In total, 21% (n=39/179) of the drugs exhibited sensitivity (median IC50 < 30 µM), with significant enrichment for topoisomerase, RNA/protein synthesis, proteasome, and HDAC inhibitors. The top five drugs with the lowest IC50 values were romidepsin, dactinomycin, carfilzomib, plicamycin, and omacetaxine with median values of 10, 31, 145, 303, and 400 nM. Hierarchical clustering of IC50 data revealed at least two distinct drug response clusters defined by sensitivity to tyrosine kinase inhibitors. When considering the Cmax/IC50 ratio as a potential predictive marker of treatment response (>1), the HDAC inhibitors belinostat (74.5), romidepsin (69.7), the proteasome inhibitor carfilzomib (34.6), and the anthracyclines epirubicin (2.6), and doxorubicin (1.8), and the PI3K inhibitor idelalisib (1.6) are the most promising drug candidates for further in vivo evaluation. We provide the first comprehensive insight into the pharmacological landscape of meningiomas. This data might serve as the foundation for future clinical studies on the systemic treatment of aggressive meningiomas.
EXTH-58. BLOCKING IMMUNE CHECKPOINT— LAIR1: DISRUPTING THE LAIR1—FXIII-A—COLLAGEN IMMUNOSUPPRESSIVE CIRCUIT FOR ENHANCED ANTITUMOR THERAPEUTICS
Authors: Tao Haipeng , Chen Dongjiang , Yang Changlin , Nguyen Duy T , Liu Ruixuan , Liu Tianyi , Chakraborty Avirup , Hou Alicia Y , Petit Nicole A , Von Roemeling Christina , Lin Tuo , Davis Robert W , Zhang Janie , Pepe Alfonso , Pedro Diego Ivan , Mendez-Gomez Hector , Weidert Frances , Jin Dan , Long-James Kaytora , Castillo Paul C , Ligon John A , Ghiaseddin Ashley , Sayour Elias J , Rahman Maryam , Deleyrolle Loic P , Kim Betty Y S , Mitchell Duane A , Sawyer W Gregory , Huang Jianping
Published: November 2024

BACKGROUND

Recent evidence indicates that tumor-associated myeloid cells (TAMCs), including tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs), play a crucial role in glioblastoma (GBM) immunosuppression and progression. These cells can constitute up to 50% of the total mass in GBM tumors and are pivotal in dampening the immune response, which negatively impacts patient survival. Targeting TAMCs represents a promising strategy to overcome the limitations of current cancer treatments. However, drug development in this area remains limited. Our study focuses on Leukocyte-Associated Immunoglobulin-like Receptor 1 (LAIR1), a novel immune checkpoint overexpressed on TAMCs within GBM. We comprehensively analyze LAIR1’s inhibitory role in cancer progression, highlighting its potential as a therapeutic target.

METHODS

Both in vitro and in vivo experiments were conducted. LAIR1 wild-type (LAIR1+/+) and knock-out (LAIR1-/-) tumor models were tested for antitumor response and intratumoral immune landscape. We also utilized 2D and 3D cultures to evaluate the effects of antibody blockade (aLAIR1) alone and in combination with CAR-T therapy (8R-70CAR) in both human and mouse GBM models.

RESULTS

We have uncovered a previously unrecognized immunosuppressive LAIR1→ Factor XIII A (FXIII-A)→ Collagen IV circuit across cancer types. Inhibiting LAIR1, either through genetic LAIR1-/- or aLAIR1, effectively disrupts this immunosuppressive pathway and results in enhanced peripheral and tumor-infiltrating memory CD8 T cell populations, a phenotypic shift of TAMs towards an M1 profile, and a decrease in tumor collagen deposition. These collective effects contribute to the normalization of the TME and facilitate improved interactions between T cells and tumor cells, leading to a more effective antitumor response. Notably, using aLAIR1 as a standalone intervention or combined with CAR T cell therapy demonstrates enhanced antitumor efficacy in preclinical models resistant to chemo-radiation and anti-PD-1 treatments.

CONCLUSIONS

We discovered a novel mechanism by which LAIR1 contributes to GBM progression. LAIR1 blockade holds promise in reversing suppressive TME and serving as a therapeutic strategy.
EXTH-59. ESTABLISHING GAUSSIA LUCIFERASE REPORTER AS A BIOMARKER FOR ESTIMATING THERAPEUTIC RESPONSE AND PROGRESSION-FREE SURVIVAL IN PATIENT-DERIVED XENOGRAFT MODELS OF GLIOBLASTOMA
Authors: McKinney K’Ashé , Tse Christopher , Wang Chencai , Sanvito Francesco , Nathanson David , Ellingson Benjamin M
Published: November 2024

Serial monitoring of tumor burden in patient-derived xenograft (PDX) models used for testing new cancer drugs via MRI and other imaging techniques can be costly. We theorized that transducing the Gaussia luciferase (GLuc) reporter gene into glioma PDX models (GliomaPDOX) allows for GLuc to be used as a biomarker for tumor burden. This current study investigates whether changes in the rate of GLuc secretion over time (i.e., “growth rate” changes) can predict survival in GliomaPDOX. Optimal cutoff values to define disease progression via GLuc measurements were established resulting in a strong association between progression-free survival (PFS) and overall survival (OS). The pLenti-CMV-sGluc-T2A-EGFP plasmid was packaged into a second-generation lentiviral system via HEK293FT cells, and the resulting virus transduced into directly-isolated glioma patient cells to establish the MGMT-Unmethylated and MGMT-Methylated GliomaPDOX. MGMT-Unmethylated GliomaPDOX were treated with placebo or Temozolomide (TMZ) until endpoint. MGMT-Methylated GliomaPDOX were treated with placebo or TMZ for three weeks or TMZ for six weeks until endpoint. Treatment response was monitored through GLuc measurements obtained via tail blood collection. The optimal cutoff for time to progression was a 30% increase in GLuc, which yielded a significant positive association between PFS and OS across all models and treatments (R2 = 0.8177, p<0.0001). Compared to the MGMT-Methylated placebo and MGMT-Unmethylated groups, the MGMT-Methylated treatment groups exhibited substantial changes in GLuc growth rates and significantly longer PFS and OS (p<0.0001). More specifically, the six-week MGMT-Methylated TMZ-treated group demonstrated a significant difference in GLuc growth rates and a considerable PFS (p<0.0038) and OS increase (p<0.0049) when compared to the three-week MGMT-Methylated TMZ-treated group. Therefore, GLuc measurement is a valuable biomarker for PDX tumor burden and can be used to estimate treatment response and PFS.
EXTH-65. EXPLORING ANTIHISTAMINES TO TREAT GLIOBLASTOMA
Authors: Yadav Poonam , Vengoji Raghupathy , Doss David , Jain Maneesh , Batra Surinder , Shonka Nicole
Published: November 2024

BACKGROUND

Glioblastoma (GBM) is an aggressive and lethal primary malignant brain tumor with a 5-year survival of 6.8%. Interestingly, people with allergies, atopy, or asthma are less likely to develop GBM. A recent study recognized that high histamine receptor 1 (HRH1) expression is inversely related to overall and progression-free survival.

METHODS

We used a bioinformatics tool, iLINCS, which, after analyzing 99 GBM and 38 healthy samples, identified 36 drugs that can reverse GBM signatures. Based on the concordance score and blood-brain barrier permeability, we selected brompheniramine (Brom), a first-generation HRH1 antagonist, as a potential candidate. HRH1 expression analysis was done on human and mouse GBM cell lines by immunoblotting. The effect of Brom alone or in combination with temozolomide (TMZ) was investigated on proliferation, DNA damage and apoptosis in human (U118 and U251) and three syngeneic (EGFRvIII, p16-/- & GFAP Cre, PTEN+/-, p53R172H+/-, EGFRvIII & GFAP Cre, PTEN-/-, p53R172H-/- & GFAP Cre) cell lines. GBM orthograft mouse models were used to test the efficacy of combination therapy.

RESULTS

HRH1 is highly expressed in human and syngeneic GBM cells. This expression is further increased in TMZ-resistant cells. Interestingly, the addition of histamine, induced TMZ resistance in GBM cells. TMZ with Brom decreases proliferation in mouse and human GBM cells, and Brom is non-toxic to non-transformed cells. Combination treatment increases DNA damage and decreases the DNA repair mechanism, possibly by downregulating the expression of O6methylguanine-DNA methyltransferase (MGMT). In the GBM orthograft mouse model, the combination therapy reduced tumor volume and significantly increased survival compared to single-agent treatment.

CONCLUSIONS

Brom is non-toxic; Brom, in combination with TMZ, enhanced the anti-tumor efficacy of TMZ both in in vitro and in vivo GBM models. Further studies in spontaneous mouse models are planned.
EXTH-72. INTEGRATED MULTIOMIC ANALYSIS OF ISOGENIC EGFRVIII MODELS OF GBM REVEALS EXPLOITABLE THERAPEUTIC VULNERABILITIES
Authors: Lin Benjamin , Shelton Abigail , Skinner Kasey , Smithberger Erin , Ziebro Julia , Bash Ryan , Angus Steven , East Michael , Johnson Gary , Furnari Frank , Miller C Ryan
Published: November 2024

Glioblastoma (GBM) is the most common primary malignant brain tumor with an abysmal 15-month median survival. Therefore, novel therapeutic interventions are urgently needed. EGFR is a receptor tyrosine kinase that is mutated in over 50% of GBM and is a logical target for precision oncology approaches. While aberrant EGFR signaling has been successfully targeted in other cancers, early attempts to target EGFR in GBM clinical trials have not been successful. Since these early trials, several studies have revealed that GBM EGFR biology is unique and cannot be generalized from other EGFR-driven neoplasms. To better understand EGFR biology in a GBM-specific context, we have characterized the GBM transcriptome with RNAseq, the epigenome with CUT&RUN, and the kinase proteome with Multiplexed inhibitor beads with Mass Spectrometry (MIB-MS), collectively referred to as ‘multiomics’, after modeling EGFR resistance. An isogenic mouse astrocyte (mAc) model of GBM was genetically engineered to overexpress EGFRvIII (CEv3), the most common EGFR mutation in GBM. Expression of EGFRvIII induces a unique multiomic profile that mediates many hallmark cancer phenotypes including proliferation and stemness. Chronic EGFR resistance was modeled both in vitro and in vivo through continuous exposure to erlotinib or gefitinib, EGFR tyrosine kinase inhibitors (TKI). Additionally, acute EGFR resistance was modeled using a single exposure to EGFR TKI afatinib or neratinib in vitro over a 48-hour time course. Preliminary multiomic characterization of these data has revealed several targets that can be further investigated for therapeutic exploitation. Further investigation into these targets using orthotopic allografts with CEv3 cells shows that combinatorial therapy with neratinib and abemacilib, a CDK inhibitor, significantly (p < 0.001, n= 20 mice per group) extends survival (56 days) compared to neratinib alone (31.5 days). Future integrated multiomic analysis aims to elucidate the synergistic relationship between neratinib and abemacilib.
EXTH-82. TUMOR ORGANOID PREDICTED THERAPEUTIC RESPONSES TO NOVEL EPIGENETIC DRUGS VIA HIGH-THROUGHPUT SCREENING
Authors: Bae Goeun , Palacios Milagros Suarez , Powell Reid T , Stephan Clifford C , Li Xiaonan , Du Yuchen
Published: November 2024

INTRODUCTION

The treatment choices for pediatric brain tumors are still very limited. Epigenetic therapy emerges as a promising option recently. The lack of in vitro models that represent tumors in vivo and can be scalable for large scale drug screening is major barrier. We have developed tumor organoids from patient-derived orthotopic xenograft and performed a multi-stage high throughput screening for single or combined epigenetic agents and radiation therapy in tumor organoids.

METHOD

Primary xenograft tumor cells were cultured in matrix and cancer stem cell culture medium in 384-well plates. Radiation sensitivity was examined at 5 different doses. Epigen40 (40 drugs/compounds) targeting various epigenetic modifications was used alone to identify agents with the most cell killing (4 doses for up to 19 days). The drugs that showed partial activity were combined with radiation (at 5 doses) to evaluate additive or synergistic effects. The anti-tumor efficacy of selected drug was then evaluated in vivo.

RESULTS

The conditions of organoid growth and screen variability were optimized. 7 tumor organoids including 4 glioblastomas and 3 medulloblastomas were successfully established and characterized. The different radio-sensitivities were observed among these models. 7 compounds (JIB-04, SP2509, AS-8351, GSK J4 HCI, 3-Deazaneplanocin A HCL, Chaetocin, TC-E-5003) were shown to effectively suppress organoid growth. Chaetocin, methyltransferase SUV39H inhibitor, demonstrated broadly active and highly potent inhibition across all 7 tested organoids. In addition, bioinformatic analysis identified a subset of epigenetic inhibitors combined with radiation that produced additive anti-tumor activities in vitro. Unfortunately, in vivo treatment of Chaetocin (0.25mg/kg) didn’t convey consistent anti-tumor effects as shown in vitro whereas a high risk of drug toxicity to the mice.

CONCLUSION

Tumor organoids were successfully developed from primary tumors. With our optimized assay using primary tumor organoids and a multi-stage high throughput drug screening, a novel panel of epigenetic drugs that effective alone or additively with radiation was identified.