tbuckley/cabot-search huggingface dataset:
DDDR-02. NOVEL MDM4 INHIBITOR CEP-1347-BASED THERAPY FOR P53 WILD-TYPE MALIGNANT MENINGIOMA
Authors: Yuta Mitobe, Shuhei Suzuki, Yurika Nakagawa-Saito, Keita Togashi, Asuka Sugai, Yukihiko Sonoda, Chifumi Kitanaka, Masashi Okada
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Although a significant proportion of meningiomas are clinically aggressive, there is currently no effective chemotherapy for them. An increasing number of studies have been conducted to develop targeted therapies, but none have focused on the p53 pathway as a potential target. In this study, we determined the in vitro and in vivo effects of CEP-1347, a novel small-molecule inhibitor of MDM4 with known safety in humans, on malignant meningioma cells, and also investigated the effects of CEP-1347 when combined with MDM2 inhibition. METHODS The effects of CEP-1347 and MDM4 knockdown on the p53 pathway in human meningioma cell lines with and without a p53 mutation were investigated using RT-PCR and Western blot analyses. The growth inhibitory effects of CEP-1347 were investigated in vitro and in a mouse xenograft model of meningioma. We also investigated the effects of CEP-1347 in combination with genetic or pharmacological inhibition of MDM2 in vitro. [Results] CEP-1347 at clinically relevant concentrations inhibited MDM4 expression, activated the p53 pathway in malignant meningioma cells with wild-type p53, and inhibited growth preferentially in cells expressing wild-type p53, which was mostly mimicked by MDM4 knockdown. CEP-1347 effectively inhibited the growth of malignant meningioma xenografts at a dose substantially lower than the maximum dose that could be safely administered to humans. The small-molecule MDM2 inhibitor RG7112 effectively cooperated with CEP-1347 to reduce MDM4 expression, activate the p53 pathway, and inhibit cell growth. [Conclusion] Our findings suggest that targeting the p53 pathway with CEP-1347 is a novel and viable approach to treating aggressive meningiomas, with even greater efficacy when combined with MDM2 inhibitors.
DDEL-18. OPTIMIZED METHOD TO QUANTIFY TTFIELDS-INDUCED PERMEABILIZATION OF CELL MEMBRANES
Authors: Melisa Martinez-Paniagua, Sabbir Khan, Chirag Patel
Journal: Neuro-Oncology (2024)

Abstract Tumor Treating Fields (TTFields) therapy is FDA-approved for glioblastoma. Using plate-based readouts of FITC-dextran fluorescent probes in U87 human glioblastoma cells, we previously reported increased uptake of FITC-dextrans (4-20kDa) post-TTFields exposure. However, this approach is unable to distinguish FITC-dextran uptake in live-vs-dead cells post-TTFields exposure. We demonstrate flow cytometry (FC) as a more robust and economical method to quantify the amount of FITC-dextrans entering the cells. We first identified the optimal [FITC-dextran] for the FC-based approach (titration 0-6.5mg/mL). Cells were then seeded onto coverslips and exposed to 200kHz TTFields, 1-3V/cm peak-to-peak (inovitro systemTM, Novocure), or no-TTFields (control), for 24-72h. Cells were harvested and stained for 1h using 4kDa or 20kDa FITC-dextrans. Cells were washed and analyzed by FC for mean±SD fluorescence intensity, and compared by unpaired t-test. Dead cells were excluded using propidium iodide staining. In the control vs. TTFields group, 4kDa FITC-dextrans had significantly increased uptake at 24h (4.9±0.3 vs. 8.0±1.7, p=0.01), 48h (6.5±0.2 vs. 8.3±1.0, p=0.01), and 72h (5.7±0.3 vs. 8.8±1.0, p=0.001). Likewise, in the TTFields group, the 20kDa FITC-dextrans had significantly increased uptake at 24h (5.6±0.3 vs. 7.5±0.9, p=0.006), 48h (4.8±0.3 vs. 6.6±0.8, p=0.006), and 72h (5.3±0.2 vs. 11.3±2.6, p=0.004). In the TTFields group, the 20kDa FITC-dextrans had significantly increased uptake between the 24h and 72h timepoints (p=0.03). The FC-based method utilized 0.36mg of FITC-dextrans/sample, much less compared to the 1-3mg recommended for plate-based methods. Another advantage of the FC-based method was exclusion of the dead cell population after TTFields exposure. We validated a FC-based-method that is economical and can reproducibly quantify the membrane permeabilization induced by TTFields. Compared to control conditions, TTFields increase membrane permeabilization of cells that remain alive after TTFields exposure, in a time-dependent manner for the 20kDa probe.
TMET-39. DUAL TARGETING OF MAP KINASE SIGNALING AND METABOLISM IS A THERAPEUTIC VULNERABILITY IN PEDIATRIC DIFFUSE MIDLINE GLIOMAS
Authors: Taylor Gatesman, Stephanie Casillo, Akanksha Chilukuri, Srinidhi Varadharajan, Daniel Premkumar, Esther Jane, Brenden Johnson, Tritan Plute, Matthew Halbert, Andrea Cruz, Taylor Abel, Stephen Mack, Ian Pollack, Sameer Agnihotri
Journal: Neuro-Oncology (2024)

Abstract Metabolic reprogramming in pediatric diffuse midline glioma is driven by gene expression changes induced by the hallmark histone mutation H3K27M, which results in aberrantly permissive activation of oncogenic signaling pathways. Previous studies of diffuse midline glioma with altered H3K27 (DMG-H3K27a) have shown that the RAS pathway, specifically through its downstream kinase, extracellular-signal-related kinase 5 (ERK5), is critical for tumor growth. However, there remains a knowledge gap in identifying effectors of ERK signaling and their roles in DMG-H3K27a. Leveraging several patient multi-omic datasets, we identified a unique relationship between ERK5 and brain tumor glycolysis. We establish that ERK5 is a critical regulator of cell proliferation and glycolysis in DMG-H3K27a, where ERK5 knockdown leads to decreases in glycolysis and increases in mitochondrial metabolism. We demonstrate through loss of function and overexpression studies that ERK5 mediates glycolysis through regulation of glycolytic enzyme Phosphofructo-2-Kinase/Fructose-2,6-Biphosphatase 3 (PFKFB3). PFKFB3 is a protein that catalyzes the synthesis or degradation of fructose-2,6-bisphosphate (F2,6BP). Furthermore, we establish a novel mechanism, in which ERK5 mediates PFKFB3 expression via activation of MEF2A, an oncogenic transcription factor. DMG-H3K27a cells are sensitive to the loss or inhibition of PFKFB3 both in vitro and in orthotopic mouse models. However, monotherapy is ineffective in heterogenous diseases such as gliomas, including DMG-H3K27a. To combat this, we show multi-targeted therapy against the ERK5-PFKFB3 axis is synergistic in vitro and in vivo. Multi-targeted drug therapy against the ERK5-PFKFB3 axis, such as with small-molecule inhibitors, may represent a promising therapeutic approach in patients with pediatric diffuse midline glioma. Moreover, we have identified resistance to our dual therapy using several systems biology approaches, which we are currently investigating and validating. Collectively, our study defines a novel, targetable axis in DMG-H3K27a and highlights the importance of tumor cell metabolism in defining therapeutic vulnerabilities.
BIOM-05. FUSION TRANSCRIPTOME LANDSCAPE IN GLIOBLASTOMA
Authors: Sonikpreet Aulakh, Joanne Xiu, Shawn Kothari, Soma Sengupta, Michael Glantz, Manmeet Ahluwalia, Theodore Nicolaides, Mark Gilbert
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND For most patients with glioblastoma (GBM), no truly effective salvage therapies exist. However, there are compelling examples in oncology where gene fusions lead to functioning oncoproteins that are highly effective targets (ie BCR-ABL1 in CML). Using a large genomic database, we sought to determine the prevalence of fusion transcripts in GBMs. METHODS A total of 4392 GBMs were tested at Caris Life Sciences (Phoenix, AZ). Mutations were detected by NextGen sequencing of DNA (592-gene panel or whole exome sequencing); gene fusions were detected by Whole Transcriptome Sequencing. All tumors were wild type for IDH1/2. Significance was tested by Fisher-Exact and ChiSquare and adjusted by Benjamini-Hochberg (q &amp;lt;0.05). RESULTS Overall, pathogenic fusions were found in 428 (9.7%). The most prevalent were FGFR3 [N=159 (37%), highest FGFR3:TACC3, N=134], MET [N=92 (21%), highest PTPRZ1:Met, N=31; ST7:MET N=25; CAPZA2: MET, N=23), EGFR [N=87(20%), highest EGFR:SETP14, N=21 and SEC61G: EGFR, N=19], NTRK2 (N=27), PDGFRA (N=23), ROS1 (N=14) and BRAF (N=10). Other actionable fusions including ALK (N=3), NTRK3 (N=3), RAF1(N=3), RET (N=3), NTRK1(N=2) were seen. Tumors with fusions were more likely to have pathogenic gene amplifications including: MET (7.5% vs. 0.7%), FGFR3 (5% vs. 0.2%), CDK4 (17% vs. 11%) and MDM2 (12% and 7.5%) but less frequent EGFR mutation (6.1% vs. 18%), amplification (6.1% vs. 18%) and EGFRvIII mutation (11.9% vs. 22.5%), RB1 (2.9% vs. 11.5%) and TP53mutation (22% vs. 30%) (all q&amp;lt;0.05). EGFR fusions are enriched with EGFR amplification (92%) and EGFRvIII mutation (51%); cMET fusion with MET amplification (40%). CONCLUSIONS Comprehensive molecular profiling reveals that approximately 10% of IDH WT GBMs carry oncogenic fusions that may be therapeutic targets. Broad spectrum of observed fusions underscores the need for novel clinical trial designs to allow efficient enrollment for prospective testing of potential targeted agents.
BIOM-34. INTRACRANIAL MANAGEMENT OF HER-2 OVEREXPRESSION BREAST CANCER WITH EXTENSIVE VOLUME OR SYMPTOMATIC BRAIN METASTASES
Authors: Juan Li, Junjie Zhen, Ruyu Ai, Mingyao Lai, Hui Wang, Linbo Cai
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND HER-2 overexpression in breast cancer often leads to brain metastases, necessitating effective intracranial control strategies. This study aimed to evaluate the correlation between intracranial disease volume, symptomatic presentation, and treatment outcomes in HER-2 overexpressing breast cancer patients with brain metastases. METHODS A retrospective analysis was conducted on cases of HER-2 overexpressing breast cancer patients with brain metastases. Clinical records were reviewed to extract patient demographics, treatment modalities, and intracranial disease characteristics. Intracranial tumor burden was quantified at diagnosis and post-initial treatment. High intracranial tumor burden was defined as either total metastatic volume &amp;gt;15 cc, or the largest lesion &amp;gt;3 cm. Responses were assessed using established criteria. The correlation between intracranial disease parameters and intracranial progression-free survival (PFS) and overall survival (OS) was determined. RESULTS The study comprised 65 patients with HER-2 overexpression breast cancer and brain metastases. Symptomatic presentation was observed in 69.2% of patients at the diagnosis of brain metastases. Treatment with HER-2 target therapy alone or in combination with other modalities resulted in substantial intracranial responses, with 81.5% achieving at least a partial response at 3 months from therapy initiation. Median intracranial PFS and OS for patients with high intracranial burden were 9 and 22 months, respectively. Patients with high intracranial burden and symptomatic presentation at diagnosis demonstrated worse PFS and OS to those with lower burden and absence of symptoms (p &amp;lt; 0.05 for each). CONCLUSION Intracranial control in HER-2 overexpressing breast cancer patients with large volume or symptomatic brain metastases appears promising with combination with HER-2 targeted therapy and radiotherapy. Despite the varying intracranial disease burdens and symptomatic presentations, the use of HER-2 targeted therapy combined with radiotherapy demonstrates favorable intracranial responses, highlighting their potential in managing such cases.
IMMU-58. BCAT1 TARGETED METABOLIC REPROGRAMMING PLAYS CRITICAL ROLES IN MODULATING MYELOID DERIVED SUPPRESSOR CELL FUNCTION IN GLIOBLASTOMA
Authors: Christina Jackson, Yi Ning, Kate Jones, Celeste Simon, Will Bailis
Journal: Neuro-Oncology (2024)

Abstract A key component that has limited the efficacy of immunotherapy in glioblastoma (GBM) is the significant infiltration of immunosuppressive myeloid cells. Our previous work characterized myeloid derived suppressor cells (MDSCs) unique to GBM that drive tumor growth and immune suppression. Transcriptomic and flow cytometric analyses demonstrated that the most induced programs in these MDSCs are dominated by metabolic and mTOR pathways. Therefore, we aimed to understand the role of metabolic reprogramming in MDSC differentiation and immunosuppressive function. Using single cell RNA sequencing, we identified overexpression of enzymes and transporters involved in branched-chain amino acid (BCAA) metabolism, notably branched chain aminotransferase 1 (BCAT1), the first enzyme in the metabolic pathway. Intriguingly, this was only found in specific populations of early and monocytic MDSCs (E-MDSCs, M-MDSCs), and not polymorphonuclear MDSCs (PMN-MDSCs). Using established MDSC modeling systems, we found that M-MDSC differentiation and T cell suppressive function are dependent on BCAAs and can be hindered by pharmacological inhibition of BCAT1 activity or genetic knockout of BCAT1. We also establish that the influence of BCAA on M-MDSC function is specifically reliant on the BCAT1-mediated step of BCAA metabolism. To determine the underlying mechanism driving BCAT1’s impact on M-MDSC function, we evaluated the activity of signaling pathways known to be critical to M-MDSCs including the mTORC1 pathway. We found that the impact of BCAA and BCAT1 activity on M-MDSC function is abrogated by inhibition of mTORC1 pathway with reduction in M-MDSC differentiation and activity. Consistent with our single cell RNA sequencing analysis, modulation of BCAA levels and BCAT1 activity had no impact on PMN-MDSCs. Our results underscore the critical role of BCAT1 in preferentially modulating M-MDSC activity through mTORC1 signaling. Our finding paves the way for discovery of a targetable therapeutic approach to harness immunometabolism in myeloid cells to develop novel immune therapies.
DDDR-03. DEVELOPMENT OF ANTI-TUMOR AROMA THERAPY FOR GLIOBLASTOMA WITH LEMONGRASS ESSENTIAL OIL
Authors: Norihiko Saito, Nozomi Hirai, Yuki Koyahara, Yu Hiramoto, Satoshi Fujita, Haruo Nakayama, Morito Hayashi, Keisuke Ito, Satoshi Iwabuchi
Journal: Neuro-Oncology (2024)

Abstract INTRODUCTION Aroma essential oils apply to cancer therapy because of their immune-enhancing and sedative effects, and their ability to reduce the side effects of chemotherapy. Recently, aroma essential oils have also been reported to have anti-tumor effects. We investigate the anti-tumor effects of aromatic compounds contained in essential oils as a novel treatment for glioblastoma. In this study, we analyzed the antitumor effect of lemongrass essential oil and investigated its antitumor aroma therapy for glioblastoma. methods and RESULTS Human glioblastoma cells (U87, T98G) and mouse brain tumor cells (RSV-M) were used in the study. Tumor cells were cultured in the presence of lemongrass essential oil for 72 hours, and the growth inhibitory effect was observed, suggesting that the evaporated lemongrass essential oil components acted on tumor cells in the vicinity. In addition, a similar effect was observed with citral alone, which is the main component of lemongrass. Analysis of the effects of citral revealed that citral strongly binds to MARK4 and inhibits its enzyme activity, and that citral decreases the phosphorylation of tau protein. Next, a mouse brain tumor model with RSV-M was established, and the anti-tumor effect of lemongrass essential oil was studied. The results showed that the mice that inhaled lemongrass essential oil for 12 h/day had a significantly prolonged survival period compared to the control group. DISCUSSION Citral is the main component of lemongrass essential oil, which contains 70-80% of lemongrass essential oil. This study suggests a mechanism of inhibition of tumor cell proliferation by citral in malignant gliomas. Citral is a volatile monoterpene, and its anti-tumor effect was demonstrated by diffusion through evaporation. CONCLUSION Citral in lemongrass essential oil shows anti-tumor effects and is expected to be applied to a new glioblastoma therapy using “aroma”
CTNI-16. MONOGERM, A NOVEL PROOF-OF-PRINCIPLE BAYESIAN PHASE II TRIAL DESIGN OF CARBOPLATIN OR VINBLASTINE MONOTHERAPY INDUCTION PRIOR TO RADIOTHERAPY FOR INTRACRANIAL GERMINOMA
Authors: Laura Kirton, John Apps, Anna Lawson, Theodoros Arvanitis, Dipayan Mitra, Richard Gagan, Hiten Patel, Andrew Peet, Lorna Fern, Emma Williams, Nicholas Coleman, Thankamma Ajithkumar, Brigitte Bison, Gareth Veal, Daniel Stark, Giovanni Morana, James Nicholson, Lucinda Billingham, Matthew Murray
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Current European standard-of-care for localised intracranial germinoma is multi-agent chemotherapy (carboPEI: carboplatin/etoposide/ifosfamide) followed by definitive radiotherapy, with excellent survival. MonoGerm is a de-escalation, non-inferiority trial aiming to reduce toxicity. Twelve-week carboplatin (PMID:8039122) AUC10 or vinblastine (PMIDs:32642701/34520101) induction will be evaluated to test if as effective as carboPEI from SIOP-CNS-GCT-II. A novel trial design was required to answer this question pragmatically/safely. METHODS Clinical trials in rare diseases recruit slowly, allowing continuous monitoring of efficacy outcomes. Efficacy-transition-pathways (ETP) are innovative visual tools to aid determination of trial design parameters, and an extension of the dose-transition-pathways concept introduced for dose-finding trials (PMID:28733440). RESULTS MonoGerm includes two monotherapies, with each single arm recruiting six cohorts of three patients, with interim assessment after each recruited cohort and final analysis at 18 patients (total n=36). Insufficient tumour volume response (&amp;lt;30%) at 6-week safety MRI results in 12-weeks carboPEI. Primary outcome is radiological complete response (CR) by 12-weeks of induction monotherapy. A beta-binomial conjugate analysis will generate posterior probability distributions, combining observed trial data as realisations from a binomial distribution with a minimally informative Beta (1,1) prior. Decision criteria to allow early stopping at interim analyses and go/no-go decisions at final analysis are based on probabilities from these posterior distributions. ETP visually maps out parameters used to assert decisions after each interim assessment as a pyramid decision tree. For each recruited cohort and every CR outcome, estimates of the true CR rate and probabilities with associated decisions are mapped out. ETP allows clear communication between statisticians, clinicians, and patient-public-involvement (PPI) teams, facilitating informed decisions in an efficient/realistic trial design. CONCLUSION MonoGerm, a novel Bayesian de-escalation trial, funded by Little Princess Trust (https://www.littleprincesses.org.uk/), uses ETP and continuous monitoring with built-in stopping rules to ensure patient safety in this treatment de-escalation trial.
RADT-16. ADJUVANT CHEMO-RADIATION THERAPY AS A RISK FACTOR FOR POSTOPERATIVE HYDROCEPHALUS FOLLOWING RESECTION OF HIGH-GRADE GLIOMA: A PROPENSITY-MATCHED CASE SERIES
Authors: Nikita Das, Ravi Dhamija, Preety Sridharan, Joseph Swetz, Elleson Harper, Jaime Perez, Herbert Newton, Prashant Vempati, Tiffany Hodges
Journal: Neuro-Oncology (2024)

Abstract The discovery of the neural glymphatic network in the past decade has significant implications for clinical investigations on hydrocephalus. With emerging understanding of how meningeal lymphatics and perivascular pathways impact cerebrospinal fluid dynamics, it is conceivable that inflammatory and fibrotic changes induced by radiation and chemotherapy may contribute to the pathogenesis of postoperative hydrocephalus, a well-documented sequela of resective neurosurgery. This study investigates differences in adjuvant chemo-radiation therapy patterns between patients who develop hydrocephalus following high-grade glioma resection and those who do not experience this postoperative complication. A retrospective chart review identified 328 adult patients who underwent tumor resection at our institution between 2010-2020, of which 257 had high-grade gliomas. Demographic and clinical data were collected, including resection history and adjuvant chemotherapy and radiation history. Propensity Score Matching generated comparative cohorts (n=27) using covariates sex, age at first surgery, surgery type, tumor location, extent of first resection, tumor-associated seizures, ventricular opening, number of additional resective surgeries, and pre-surgical Karnofsky Performance Scale score. Independent t-tests assessed differences in adjunctive chemo-radiation trends between patients who developed hydrocephalus within 3 years postoperatively and those who did not. 27 of 257 patients (10.5%) who underwent resection for high-grade glioma developed hydrocephalus within 3 years of their first surgery. Patients who developed hydrocephalus were more likely to have initiated the Stupp protocol(P=0.004), completed the Stupp protocol(P=0.02), and undertaken multiple cycles of the Stupp protocol(P=0.0004). Additionally, these patients had a smaller time window between surgery and adjuvant chemo-radiotherapy initiation than patients who did not develop hydrocephalus (P=0.02). Importantly, engagement in other clinical trial regimens with chemotherapy or radiation therapy did not differ significantly between groups(P=0.08, P=0.49, respectively). Shortened time to initiation of chemo-radiation therapy postoperatively and increased number of chemo-radiation cycles may increase a patient’s susceptibility to develop postoperative hydrocephalus following resection of high-grade glioma.