bluuebunny/crossref_metadata_2025 huggingface dataset:
CNSC-21. THE EFFICACY OF TUMOR TREATING FIELDS IN TREATING IDH-MUTANT ASTROCYTOMA, WHO GRADE 4: AN EARLY RESULT FROM SHANGHAI HUASHAN HOSPITAL
Authors: Qiu Xianxin , Chen Lingzhao , Liang Liping , Zhou Zhirui , Liu Jiabing , Zhu Wenjia , Wu Tianqi , Pan Mingyuan , Qin Zhiyong , Wang Yang
Published: November 2024

OBJECTIVES

There is ongoing debate regarding the efficacy of Tumor Treating Fields (TTFields) for treating IDH-mutant grade 4 astrocytoma (IDHmA4). In fact, the evidence supporting TTFields in treating IDHmA4 is largely extrapolated from EF-14, of which the results stem form heterogeneous entities of glioblastoma lack of IDH status. This study was conducted by reviewing the database in our center following the release of WHO CNS 5, aiming to preliminarily explore the efficacy of TTFields and prognosticators of newly-diagnosed IDHmA4.

METHODS

This retrospective analysis included 53 consecutive patients with newly-diagnosed IDHmA4, who underwent radiotherapy at Huashan Hospital, Fudan University between September 2021 and December 2023. All patients were administered with concurrent and adjuvant temozolomide. Eleven patients received adjuvant TTFields after surgery. Information regarding patient baseline characteristics, treatment approaches and molecular markers were collected with the purpose of analyzing prognostic factors.

RESULTS

The median follow-up was 15.7 months. At the time of data cutoff of this analysis, 20 patients had tumor relapse; 3 patients died, all of them were without TTFields therapy. The most common tumor failure pattern was local recurrence (80%, 16/20). The median PFS for the entire cohort was 19.3 months, the median OS was not reached. Univariate analysis indicated that patients who received TTFields therapy tended to have longer median PFS than that of patients without TTFields therapy (24.4 months vs. 18.5 months, P=0.097). Additionally, patients younger than 40 years (24.4 vs. 18.5 months, P=0.107) or without homozygous deletion of CDKN2A/B (23.7 vs. 18.0 months, P=0.108) tended to have better median PFS. No significant independent prognostic factor was found in the multivariate analysis.

CONCLUSIONS

The overall prognosis of IDHmA4 is poor. TTFields may help to improve the outcome of patients with newly-diagnosed IDHmA4. Longer follow-up, larger sample size and prospective clinical trials are warranted for deeper comprehension.
CNSC-22. GLIOBLASTOMA CELLS EXHIBIT NEURON-LIKE EXCITABILITY IN BOTH ACUTE AND ORGANOTYPIC HUMAN BRAIN SLICES
Authors: Tong Tong , Elbæk Kirstine Juul , Eschen Jens , Ozsvar Attila , Cortnum Søren Ole Stigaard , Sindby Ann Kathrine , Kristensen Bjarne Winther , Meier Kaare , Mikic Nikola , Sørensen Jens Christian Hedemann , Capogna Marco , Ting Jonathan , Hou Wen-Hsien , Korshøj Anders Rosendal
Published: November 2024

Glioblastomas (GBM) are known for their significant intratumor heterogeneity, featuring a variety of plastic cell types that make effective treatment challenging. Recent studies have shown that neuronal-progenitor-like transcriptomic cell states at the leading edge of the tumor receive synaptic input from nearby neurons, which drives disease proliferation. However, the excitability of GBM cells remains controversial, with observations ranging from non-excitable to neuron-like excitability, complicating our understanding of their pathophysiology. In this study, we developed a novel experimental approach to study glioblastoma cells in both acute and cultured brain slices infiltrated with cancer from GBM patients. Using an adeno-associated virus for gene delivery, we selectively expressed fluorescent proteins in specific cell types. Fluorescence-guided whole-cell patch-clamp recordings were then used to analyze the electrophysiological properties of GBM cells and neurons within the tumor microenvironment. Our findings show that GBM cells have distinct electrophysiological properties, including a depolarized resting membrane potential (-31.95 ± 2.18 mV, n = 55 cells) and high membrane resistance (1.27 ± 0.19 GΩ, n = 62 cells). Approximately 56% of GBM cells at the tumor’s leading edge exhibited neuron-like excitability, generating aberrant action potentials (aAPs) upon depolarization. Collectively, our study provides direct evidence of the intrinsic excitability of GBM cells and a detailed characterization of their electrophysiological properties in the cancer-infiltrated human cortex. These insights shed new light on tumor heterogeneity and cell-cell interactions in glioblastoma, potentially guiding the development of targeted therapies.
CNSC-24. REAL-TIME HIGH-DENSITY ECOG MAPPING OF SENSORIMOTOR REGIONS AND CONSCIOUSNESS DIFFERENTIATION IN PERI-ROLANDIC GLIOMA SURGERY
Authors: Asman Priscella , Prabhu Sujit , Hall Mathew , Tasnim Israt , Pellizzer Guiseppe , Bhavsar Shyreyas , Tummala Sudhakar , Ince Nuri
Published: November 2024

INTRODUCTION

Accurately mapping sensorimotor regions is crucial for preserving motor and sensory functions in the treatment of gliomas located in the peri-Rolandic areas of the brain.

OBJECTIVE

We examined the use of high-density electrocorticography (ECoG) for passive mapping of sensorimotor regions in treating peri-Rolandic gliomas by analyzing the spatial-temporal and spectral features of real-time somatosensory evoked potentials (SSEPs), and their spectral patterns in differentiating states of consciousness.

METHODS

During surgery, SSEPs were recorded using high-density ECoG on fourteen patients (n=14), both in anesthetized and awake states. Neural data from 0.6Hz median nerve stimulation were captured at 2.4kHz and processed in real-time using MATLAB Simulink. The system displayed SSEPs’ peak activations as a 2D heat map on a screen, particularly around the 20ms time point (N20), and generated the spectral power in the gamma range using the Stockwell transform. Accuracy in delineating the central sulcus (CS) was assessed using the ROC curve, and paired t-tests compared gamma oscillations between states of consciousness.

RESULTS

Patients consistently showed clear discrimination between anterior and posterior channels at the 20ms time point, with 93.6±14.9% accuracy. Color contrast delineated the CS, correlating with the sulcus in the 3D reconstructed magnetic resonance imaging of each patient. Late gamma (60–250 Hz) modulation occurred 50 ms after stimulation onset, extending up to 250 ms in the primary somatosensory area. It was suppressed in the anesthetized state and significantly increased in the awake state (delineation accuracy: 81±10.3% and 91±13.4%, respectively).

CONCLUSIONS

These results demonstrate that SSEPs and gamma modulations can delineate sensorimotor areas and assess consciousness, significantly impacting neurosurgical planning.
CNSC-28. BRAINSTEM NEUROMODULATORY NEURONS PROMOTE GLIOMA GROWTH LOCALLY AND VIA LONG-RANGE PROJECTIONS TO MIDLINE AND CORTICAL STRUCTURES
Authors: Drexler Richard , Drinnenberg Antonia , Gavish Avishai , Yalcin Belgin , Shamardani Kiarash , Rogers Abigail , Mancusi Rebecca , Taylor Kathryn , Kim Yoon Seok , Woo Pamelyn , Ravel Alexandre , Tatlock Eva , Jokhai Rayyan , Ayala-Sarmiento Alberto , Rincon-Fernandez David , Ramakrishnan Charu , La Siverts ’Akea , Daigle Tanya , Tasic Bosiljka , Zeng Hongkui , Breunig Joshua , Loh Kyle , Deisseroth Karl , Monje Michelle
Published: November 2024

Neuronal activity robustly drives glioma progression, mediated through paracrine and synaptic neuron-to-glioma interactions. Recent research has focused on glutamatergic and GABAergic neurons, while the impact of neuromodulatory neuron subpopulations and their long-range projections remain unexplored. Here, we explore the glioma-promoting effects of serotonergic and cholinergic brainstem neurons, which project to defined regions throughout the brain. By employing optogenetic stimulation of midbrain serotonergic or cholinergic neurons in mice bearing high-grade glioma allografts or xenografts, we observed robust, circuit-specific effects of each neuromodulatory neuronal subtype on proliferation. Concordant with the anatomy of serotonergic projections, we found that serotonergic neurons of the dorsal raphe nucleus promoted glioma proliferation in the neocortex and pons, while those from the median raphe nucleus increased proliferation in the thalamus. Similarly, stimulation of cholinergic neurons in the laterodorsal tegmentum nucleus enhanced thalamic glioma growth, and stimulation of the pedunculopontine nucleus promoted pontine tumor growth. The long-range neuronal activity-regulated effects on glioma cells were mediated by neurotransmitter secretion at axon terminals, and paracrine signalling protein release locally in the brainstem. The activity-regulated paracrine factor profiles are distinct between serotonergic and cholinergic neurons, illustrating neuron subtype-specific mechanisms affecting glioma cells beyond neurotransmitter differences. Co-culture with hESC/hiPSC-derived cholinergic or serotonergic neurons demonstrated synaptic structures between both neuromodulatory subpopulations and glioma cells, indicating a synaptic component to these neuron-glioma interactions. ScRNA-seq data integration revealed distinct receptor abundances between DMGs and IDH-WT glioblastomas correlating with specific cellular states. Inhibition of these targets – such as M1 or M3 cholinergic receptors in DMG – mitigated the proliferation-inducing effects of the relevant neuron subtype on glioma cells. In summary, these findings introduce brainstem cholinergic and serotonergic neuromodulatory neurons as drivers of high-grade glioma growth in a circuit-specific manner in midline structures and in neocortex, adding to the complexity with which gliomas integrate into brain-wide neural circuitry.
CNSC-29. CIRCADIAN SIGNALING IN GLIOBLASTOMA SYNCHRONIZES TUMOR DAILY RHYTHMS AND REGULATES TUMOR PROGRESSION
Authors: Gonzalez-Aponte Maria , Damato Anna , Simon Tatiana , Aripova Nigina , Rubin Joshua , Herzog Erik
Published: November 2024

Glioblastoma (GBM) is the most common primary brain tumor in adults with a poor prognosis despite aggressive therapy. A recent, retrospective clinical study found that administering Temozolomide in the morning increased patient overall survival by 6 months compared to evening. Previous work has shown that murine and human models of GBM have cell-intrinsic circadian rhythms in expression of the core clock genes Bmal1 and Per2. This suggests that GBM has circadian rhythms that entrain to the hosts’ central clock. Understanding the mechanisms underlying circadian entrainment and tumor growth in GBM is essential to determine whether regulation of tumor biology and susceptibility to therapies varies with time of day. Here, we tested the hypothesis that daily host signaling regulates tumor growth and synchronizes circadian rhythms in GBM. We found that GBM cells transduced with luciferase reporters to record clock gene expression have intrinsic circadian rhythms, with Bmal1 peaking 8-12 h before Per2 in murine and human cell lines in vitro and in vivo. Further, intrinsic circadian rhythms in clock gene expression in GBM entrain to the host through glucocorticoid signaling, regardless of tumor type or host immune status. We found daily glucocorticoids (i.e., Dexamethasone) promoted or suppressed GBM growth depending on time of day of administration and on the clock gene, Bmal1. Blocking circadian signals, like VIP or glucocorticoids, dramatically slowed GBM growth and disease progression. Our results suggest that GBM tumors entrain to the circadian circuit of the brain and depend on clock-controlled cues like VIP and glucocorticoids to grow at specific times of day. This work may inform personalized circadian medicine to improve individual GBM patient outcomes.
CNSC-30. DETERMINING THE REGULATION AND FUNCTION OF ANGPT1 HIGH-GRADE GLIOMAS
Authors: Langhnoja Jaldeep , Wei Xin , Arounleut Phonepasong , Kundu Ipsita , Phoenix Timothy
Published: November 2024

Angiopoietin-1 (Angpt1) is a secreted protein that promotes angiogenesis and vascular stability in development and certain disease states through activation of the Tie2 receptor. However, little is known about its regulation and function in brain tumors. Angpt1 is upregulated in glial brain tumors, including high-grade gliomas and ependymomas. We find Angpt1 is expressed by specific cell populations within gliomas, along with non-tumor reactive astrocytes and perivascular mural cells. Leveraging an in vivo brain tumor modeling system we have generated glioma models to investigate how tumor cell state impacts Angpt1 expression, along with creating Angpt1 knock-out models. We find that Angpt1 expression is increased when glioma models are biased towards a more astrocytic and/or mesenchymal state, mirroring developmental expression patterns. Ongoing studies utilizing these models are being used to determine the mechanisms that regulate the dynamic expression of Angpt1 and its function in glioma pathogenesis, including tumor angiogenesis and blood-brain barrier function.
CNSC-33. GROUP3 MEDULLOBLASTOMA WITH BONE MARROW AND ABDOMINAL CAVITY METASTASIS:A CASE REPORT
Authors: Li Shaoqun , Chen Lian , Kang Haojing , Ye Minting , Lai Mingyao , Cai Linbo
Published: November 2024

Medulloblastoma is an infratentorial primitive neuro-ectodermal tumour, which is commonly occurring in childhood. It often spreads through the cerebrospinal fluid pathways with a very low rate of systemic metastases. Extra-central nervous system metastases have a poor prognosis in medulloblastoma. Here, we reported a case of Group3 medulloblastoma with bone marrow and abdominal cavity metastasis. A 10-year-old girl complained of headache, dizziness, vomiting and nausea. Magnetic resonance imaging(MRI) of the brain showed a large mass in the fourth ventricle and obstructive hydrocephalus. The surgery was performed to remove the mass and ventriculoabdominnal shunt was performed for obstructive hydrocephalus. Histological verification was proven classic medulloblastoma and next-generation sequencing confirmed molecular group of Gruop3 with MYC amplication. Radiotherapy was subsequently performed one month after the surgery. During the radiotherapy, brain MRI showed metastasis on the surface of the brain, which confer a poor prognosis. After the radiotherapy According to the therapeutic schedule, She would accept chemotherapy one month after the radiotherapy. But She suffered severe bone marrow suppression manifested as anaemia and thrombocytopenia, which can not be improved by medication and blood transfusion. A bone marrow aspiration was subsequently performed, and bone marrow smear showed large numbers of tumor cells at high magnification and was lack of normal hematopoietic cells. The girl was deteriorating rapidly with jaundice, ascites, hepatosplenomegaly and pancreatitis after the bone marrow aspiration. We found a lot of tumor cells in the bleeding tendency ascites and finally confirmed bone marrow and abdominal cavity metastasis concurrently. Eventually, She died less than a month after the metastasis and the overall survival was only 6 months. This typical case demonstrated severe bone marrow suppression of unknown origin should caused alarm and be performed bone marrow aspiration as soon as possible. The prognosis of medulloblastoma with extra-central nervous system metastases is poor and people may die in months.
CNSC-44. TARGETING OF THE YAP/TAZ-TEAD AXIS DIMINISHES VIABILITY AND DIFFERENTIATION POTENTIAL IN PEDIATRIC HIGH-GRADE GLIOMA
Authors: Macias Jorge Luis Jimenez , Oh Se-Yeong , Hu Zhengang , Yin Kevin , Sele Nisan , Boon Nikki , Sing Anson , Sloan Steven A , Read Renee D
Published: November 2024

Pediatric high-grade gliomas (pHGGs) are invasive and fast-growing brain malignancies. They account for up to 40% of all brain tumor-related deaths in childhood. Genetic alterations that characterize these gliomas include H3 onco-histone mutations and genetic alterations in receptor-tyrosine kinases (RTKs), including amplification, mutation, and gene fusions in RTKs. However, direct targeting with tyrosine kinase inhibitors (TKIs) has shown at best partial responses in patients due to the molecular heterogeneity within these tumors and the lack of pharmaceutical penetration into the central nervous system (CNS). Thus, alternative therapeutic approaches to treat pHGGs are urgently needed. The YAP/TAZ transcription factors, which cooperate with TEAD co-factors to promote target gene expression, orchestrate stem-cell fate decisions and proliferation downstream of growth factor signaling pathways, such as RTKs. We observed that YAP expression is upregulated in RTK mutant and H3 mutant pHGGs. Depletion of YAP via RNAi methods decreased proliferation, inhibited pHGG stem cell self-renewal, and induced apoptosis of pHGG cells. Use of Verteporfin (VP), a FDA-approved YAP/TAZ small molecule inhibitor, mimicked the effects seen by YAP genetic depletion. Using an in vitro human cortical organoid-tumor model in which tumor cells are engrafted to human brain cortical organoids, we screened for responses in tumor cells and in non-tumor cells in the neural microenvironment upon VP treatment, using single-cell RNA-sequencing and immunofluorescence to visualize responses. These organoid models offer improved models for modeling how the neural CNS microenvironment shapes responses of tumor cells to YAP/TAZ inhibition and VP treatments. Results from our work showing that YAP/TAZ-TEAD inhibition is a promising therapeutic avenue for management of pHGGs will be presented. Further pre-clinical work will follow to correlate observation and understand the therapeutic efficacy of YAP/TAZ-TEAD inhibition for pHGG treatment.
CNSC-59. EPIGENETIC POTENTIATION OF ANTI-TUMOR IMMUNE RESPONSES USING VIRAL MIMICRY IN GLIOMAS
Authors: Chandar Jay , Seetharam Deepa , Desgraves Jelisah , Ramsoomair Christian , Castro Jesus , Hudson Anna , Govindarajan Vaidya , Zhang Yong , Sonabend Adam , Valdez Mynor Mendez , Maric Dragan , Govindarajan Vasundara , Rivas Sarah , Lu Victor , Alvarado Alexandra , Tiwari Ritika , Sharifi Nima , DeMarino Catherine , Johnson Kory , De La Fuente Macarena , Nasany Ruham Alsiekh , Noviello Teresa , Ivan Michael , Komotar Ricardo , Iavarone Antonio , Nath Avindra , Heiss John , Ceccarelli Michele , Chiappinelli Katherine , Figueroa Maria , Bayik Defne , Shah Ashish
Published: November 2024

Clinical trials using immune checkpoint inhibition(ICI) have traditionally failed in glioblastoma (GBM). Viral mimicry, which augments anti-tumor immune responses and sensitizes response to immunotherapy in other cancers, involves the epigenetic activation of endogenous retroelements (REs). REs are silenced via the HUSH complex and H3K9me3. This process is mediated by ZNF638. We aimed to elucidate the role of viral mimicry in enhancing ICI through epigenetic reprogramming of the HUSH complex. We demonstrated that RE expression among 48 superfamilies inversely correlated with ZNF638 expression in gliomas, based on data from 71 newly-diagnosed GBMs. Using transcriptional deconvolution, we showed ZNF638 negatively correlates with innate antiviral immune response signatures(TLR3)(RTLR3=-0.300,pTLR3=0.00006). We validated these in-silico results in pure glioma cell lines, patient-derived GBM neurospheres, and syngeneic murine models. ZNF638 knockdown induced intracellular RE-mediated dsRNA signaling cascades via RIG-I and TLR3. This knockdown significantly increased PD-L1 expression(p<0.001), reduced H3K9 trimethylation, and enhanced cytoplasmic dsRNA accumulation in glioma cell lines. In patient-derived GBM neurospheres, ZNF638 knockdown upregulated immune and antiviral programs. Additionally, knockdown resulted in upregulation of several endogenous repeat elements (Alu, LTR). Single-cell RNA sequencing showed ZNF638 clustering in neural progenitor-like and oligodendrocyte-like cells, with increased retroelement expression in low ZNF638 cells. Tumors with lower ZNF638 expression showed increased CD8+ populations. Bulk RNA sequencing deconvolution revealed that ZNF638 is linked to reduced CD8 and DC infiltration in gliomas (RCD8=-0.202,RDC=-0.198;pCD8=8.79E-06,pDC=1.34E-05). In immunocompetent mice, ZNF638 KO and PD-L1 inhibition significantly improved survival (mOS >50 days, p<0.0001) and reduced tumor volume (p<0.001). Analysis of cohorts from multiple cancer types treated with anti-PD1 therapy demonstrated that ZNF638 expression predicts therapeutic response and overall survival. Our findings suggest that epigenetic reprogramming through HUSH inhibition may potentiate immunotherapy for GBM.
CNSC-60. SYNERGISTIC IMMUNOMODULATION THROUGH DUAL ANTIBODY THERAPY TARGETING CD47 AND CD24 FOR ENHANCED ANTITUMOR IMMUNITY IN GLIOBLASTOMA
Authors: Ha JongHoon , Wang Yifan , Dong Shiyan , Kim Betty Y S , Jiang Wen
Published: November 2024

Tumor cell phagocytosis by antigen-presenting cells (APCs) plays a pivotal role in fostering antitumor immunity. However, glioblastoma, known for its evasive strategies, exploits key phagocytosis checkpoints, including CD47, CD24, and beta-2-microglobulin. While mono-treatment targeting CD47 blockade has shown some antitumor responses in glioma, prolonged tumor-suppressing ability and significant extension of survival remain elusive. In this study, we combine anti-CD47 and anti-CD24 antibody treatments, unveiling a synergistic effect in promoting tumor cell phagocytosis. This enhanced phagocytosis profile triggers the activation of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway in APCs, thereby facilitating efficient T cell priming. This orchestrated interplay between innate and adaptive antitumor immunity not only attenuates glioblastoma growth and extends overall survival. These findings illuminate a promising avenue for harnessing phagocytosis modulation as a strategic approach to treat challenging tumors equipped with multiple immune checkpoints.
CNSC-62. DIFFERENTIAL SURVIVAL IMPACT OF TRASTUZUMAB DERUXTECAN IN HER2-POSITIVE VERSUS HER2-LOW BREAST CANCER PATIENTS WITH BRAIN METASTASES
Authors: Ranjan Tulika , Podder Vivek , Bardhan Mainak , McCracken Andrea , Hurmiz Charlie , Mahtani Reshma L , Ahluwalia Manmeet Singh
Published: November 2024

BACKGROUND

Brain metastases (BM) in breast cancer (BC) present significant treatment challenges, with varying outcomes based on HER2 expression. There is limited real-world evidence of outcomes with the use of trastuzumab deruxtecan (T-DXd) on survival in patients (pts) with HER2-low and HER2-positive (HER2+) MBC with BM.

METHODS

We conducted a retrospective cohort study using data from seven US-based health systems within the Guardian Research Network (GRN). We included pts treated with T-DXd from December 2019 to December 2023, classified as HER2-low (IHC 1+ or IHC 2+/HER2 FISH non-amplified) or HER2+ (IHC 3+ or HER2+ with FISH amplified). Survival analysis was performed using Kaplan-Meier curves and the log-rank test.

RESULTS

125 pts with BCBM treated with T-DXd were included in the final analysis, of which 70 (56%) were HER2+ and 55 (44%) were HER2-low. The median age at BM diagnosis was 60.5 years (range 21.6 to 87.1 years). HER2 low pts had a higher prevalence of ER+ disease than HER2+ pts (81.9% vs. 55.7%, p=0.01). Most of these pts (≥75%) had received multiple prior lines of therapy. HER2+ pts with BM had a median overall survival (mOS) of 9.3 months (95% CI: 6.79-11.88), significantly longer than 4.3 months (95% CI: 1.89-6.82) in HER2-low pts (p < 0.001). At 6 months, OS for HER2+ pts with BM was 40% compared to 25% in HER2-low pts. At 12 months, OS for HER2+ pts was 20% compared to 10% in HER2-low pts.

CONCLUSIONS

This study represents the largest real-world evidence to date on the effectiveness of T-DXd in treating BM from breast cancer. HER2+ BCBM exhibited longer mOS and 12-month survival rates than pts with HER2-low disease, suggesting HER2 expression is crucial in determining T-DXd’s effectiveness. Future research should explore combination therapies and identify predictive biomarkers to optimize treatment strategies through clinical trials.
CNSC-63. THE COMPLEX RELATIONSHIP BETWEEN GENETIC ETIOLOGIES OF GLIOBLASTOMA AND PATIENT SURVIVAL: A RETROSPECTIVE ANALYSIS
Authors: Nashman Zarrar , Ullah Tasfiq , Hoffman Pauline
Published: November 2024

Data Analysis was done using the NIH GDC Data Portal with glioblastomas being the only selected primary diagnosis (n=1381). Kaplan Meier plots were generated for various genes and mutations and the survival data was compared between carriers and non-carriers. Median survival was 14 months post diagnosis when all patients are clustered together. Survival Plot of patients with IDH1 R132H mutation (n=35) vs without IDH1 R132H mutation (n=538) reveals that carriers have longer survival compared to non-carriers. The next seven cases with the highest number of specific mutations were a variation between TP53 and EGFR, both genes implicated in various cancers due to their roles in cancer suppression and proliferation respectively. The ten most frequent specific mutations observed were all missense mutations. Furthermore, patients without PTEN mutations (n=98) had better survival compared to patients who had PTEN mutations (n=623), particularly observed after one year. For specific mutations, IDH1 R132H was detected in 35 patients. All other specific mutation groups had less than 30 patients, therefore, a larger cohort would be beneficial in understanding the survival outcomes of various specific mutations. In terms of total number of mutations per gene, PTEN had the highest followed by TP53 and EGFR. In understanding the survival data, the best target for therapies can be narrowed, regardless of the increasingly evident polygenic pathology of glioblastoma.
CNSC-65. ELECTROPHYSIOLOGICAL AND SPATIAL TRANSCRIPTOMIC PROFILING OF GLIOMA-INFILTRATED CORTEX REVEAL LAYER SPECIFIC ALTERATIONS
Authors: Daniel Andy , Aabedi Alexander , Umbach Gray , Negussi Mikias , Herr Sanjeev , Gonzales Cesar Nava , Krishna Saritha , Kaur Jasleen , Fazzari Elisa , Nejo Takahide , Raleigh David , Bhaduri Aparna , Joseph Kevin , Ravi Vidhya , Brang David , Hervey-Jumper Shawn
Published: November 2024

Specialized neocortical circuits selectively organize neuronal signals and encode features of cognitive processing via local and long-range connections. Since glioma-infiltrated cortex is excitable and can participate in cognitive processing, the underlying laminar structure and functionality may still be preserved despite infiltration. Moreover, since glioma cells remodel existing neural circuits and microenvironmental factors drive invasion and proliferation, neuron-glioma interactions may demonstrate layer specificity. As glioma-infiltrated cortex remains poorly understood, we sought to characterize these regions using electrophysiological, structural, and genomic approaches. We assessed the power spectra of normal-appearing and glioma-infiltrated cortex using magnetoencephalography and subdural high-density electrode arrays. Immunohistochemistry of formalin-fixed paraffin-embedded (FFPE) samples of infiltrated cortex enabled protein-level neuronal and glioma identification to determine laminar preservation and spatial invasion patterns. Spatial transcriptomics of FFPE tissues and single-nucleus RNA-sequencing were used to identify cell populations, genomic alterations, and cell-cell communication within and across samples at testing and validation sites across the US and Europe. Increased delta range (1-4 Hz) power and decreased power in the beta range (12-20 Hz), activity thought to originate from deep layers, were identified as robust features of infiltrated cortex which were maintained across glioma subtypes (n = 139 patients) and preserved in a validation cohort (n = 8 patients). Immunohistochemistry revealed greater tumor burden within deep laminae regardless of glioma subtype (n = 20 samples). Tissue proteomics and spatial genomics analyses performed using glioma-infiltrated cortical samples (n = 10 samples; 29,011 spots) confirmed routine preservation of laminar organization, greater tumor burden in deep layers, as well as layer specific differences in glioma-related expression programs. Cell-cell communication analyses demonstrated increased interactions in glioma-infiltrated cortex across layers. These findings suggest that laminar structure may be preserved in glioma-infiltrated cortex while remodeling of neural circuits alters spatiotemporal activity in a predictable manner and support a deep to superficial invasion pattern. Thus, investigating glioma infiltration using layer-centric approaches may facilitate novel insights into neuron-glioma interactions.
CNSC-67. ANATOMICAL ORGANIZATION AND ELECTRICAL PROPERTIES OF GLIOMA-INNERVATING NEURONS
Authors: Hsieh Annie , Ganesh Sanika , Kula Tomasz , Irshad Madiha , Ferenczi Emily , Wang Wengang , Chen Yi-Ching , Hu Song-Hua , Li Zongyu , Joshi Shakchhi , Haigis Marcia , Sabatini Bernardo
Published: November 2024

Gliomas are the most common malignant primary brain tumors and are often associated with severe neurological deficits and mortality. Unlike many cancers, gliomas rarely metastasize outside the brain, indicating a possible dependency on the brain’s unique microenvironment. Recent discoveries have highlighted the existence of neuron-glioma synapses, suggesting that glioma cells depend on neuronal inputs and AMPA-receptor-mediated glutamate signaling for their proliferation. Yet, the specific locations and properties of the neurons that innervate gliomas remain elusive. In this study, we utilized transsynaptic tracing with a pseudotyped, glycoprotein-deleted rabies virus to specifically infect TVA and glycoprotein-expressing human glioblastoma cells in an orthotopic xenograft model. This approach allowed us to identify the presynaptic neuronal inputs to the glioma. Comprehensive whole-brain mapping and quantification revealed that these glioma-innervating neurons, predominantly glutamatergic, exhibit a consistent input pattern influenced by the tumor’s locations and engage selective neuromodulatory pathways. Notably, the electrophysiological properties of these neurons mirror those innervating the cortex in vivo. Our study introduces a novel method for investigating glioma-innervating neurons and reveals that these neurons are consistently integrated into the glioma network, displaying distinctive location-dependent neuromodulatory patterns. Our findings offer a promising scaffold for future interventions aimed at disrupting these critical neuronal inputs, potentially redefining therapeutic strategies against brain tumors.
CNSC-68. SEX DIFFERENCES IN GLYCINE BIOSYNTHESIS DRIVE RESPONSES TO COMBINED NUTRIENT DEPRIVATION AND PHARMACOLOGICAL INHIBITION IN PEDIATRIC HGG
Authors: Lu Jianyun , Marquez Camryn , Cho Kevin , Patti Gary , Rubin Joshua , Ippolito Joseph
Published: November 2024

In children and adults, high-grade gliomas (HGGs) are the most common and deadly primary brain malignancies. Generally, male HGGs occur at higher incidence and demonstrate more rapid proliferation, resulting in shorter overall male survival. Obscurity of molecular mechanisms driving this phenomenon prevents implementation of clinically effective treatments. Recently, a positive correlation between HGG cellular proliferation and metabolic reprogramming toward glycine biosynthesis was identified. By analyzing pediatric and adult HGG patient data, we discovered significantly worse outcomes unique to pediatric males bearing upregulation of serine and glycine biosynthesis transcripts. Previously, we have identified differential flux of glucose into serine and glycine biosynthesis drives sex differences in lung cancer. Therefore, we sought to confirm and target this paradigm in our NF1-/- DNp53 model of HGG. By performing metabolic tracing with [13C]-labeled glucose in male and female cells, we identified higher enrichment of [13C]-labeled serine and glycine in male cells relative to female cells. Through Western blotting, we identify male-specific upregulation of serine and glycine biosynthetic pathway enzymes in transformed cells, supporting our labelling results. Next, we sought to determine if inhibition of de-novo serine and glycine biosynthesis was similarly sex-biased. Utilizing serine-and-glycine-deprived media conditions, we identified a male-biased decrease in proliferation following pharmacological inhibition of de-novo serine and glycine biosynthesis. More precisely, in the absence of exogenous glycine, we discovered that inhibition of de-novo synthesis of glycine from serine drove male-specific decreases in proliferation. Additionally, we identified that transformed female cell robustness against inhibition of glycine biosynthesis is driven by the uptake of exogenous nucleotide precursors. These data confirm that sex differences in de-novo glycine biosynthesis drive sex differences in HGG cellular proliferation. As well, our work suggests that dietary restriction of serine and glycine, in-combination with pharmacological inhibition of de-novo glycine biosynthesis, represents a novel treatment paradigm.
STEM-01. SHARED ASTROCYTE-LIKE GLIOMA STEM CELLS DRIVE HETEROGENEITY AND IMMUNE DYNAMICS IN ADULT-TYPE DIFFUSE GLIOMAS
Authors: Zaman Ashraf , Muskovic Walter , Holton Emily , Pandya Madhavi , Zekanovic Rachael , Chin Venessa , Lam Eric , Moutinho Catia , Yeung Jacky , Teo Charlie , Sughrue Michael , Powell Joseph
Published: November 2024

Adult-type diffuse gliomas present significant treatment challenges due to their complex cellular composition and evolving nature. Understanding this heterogeneity is critical for the development of effective, targeted therapies. We conducted single-cell and single-nucleus RNA sequencing on a unique cohort of 66 tumours (single surgery) and 54 paired samples (two surgeries). This comprehensive dataset of approximately 900,000 cells allows us to dissect conserved cellular landscapes and dynamic evolution across diverse glioma subtypes. Using a novel phylogeny-based approach, we identified an astrocyte-like glioma stem cell (GSC) as the root of diverse glioma lineages. This discovery transforms our understanding of glioma development, pinpointing the GSC as a potential therapeutic target. The GSC’s similarity to healthy adult neural stem cells provides clues as to the origin of glioma heterogeneity and the shared basis of intratumoural diversity. Our analysis uncovered a shared cellular architecture across astrocytomas, oligodendrogliomas, and glioblastomas (GBMs). This architecture encompasses seven recurring malignant cell states: neuro-, oligo-, neuro-oligo-lineage, cycling (G1/S, G2/M), hypoxia-associated, and a quiescent astrocyte-like GSC. Importantly, these cell state proportions vary significantly between glioma subtypes. Additionally, we demonstrate that GBMs display substantially higher T-cell and myeloid cell infiltration than IDH-mutant gliomas. Counterintuitively, this correlates with a poorer prognosis, implying profound T-cell dysfunction and intricate myeloid cell-tumour interactions. Longitudinal analysis further highlights the dynamic nature of glioma cell populations and the immune landscape. Subtype-specific T-cell and myeloid gene expression profiles were identified, including potential targets such as PARD6G (GBM) and CXCL13 (IDH-mutant-astrocytoma), laying the groundwork for tailored immunotherapies and prognostic biomarkers. This study presents a comprehensive model of glioma heterogeneity and evolution. The model reveals a shared astrocyte-like GSC that fuels cellular diversity, coupled with distinct, dynamic immune landscapes in different glioma subtypes. These findings hold extraordinary potential for developing transformative treatment strategies. Future research functionally validating the GSC and its impact on tumour dynamics will be essential for translating these insights into improved patient outcomes.
STEM-05. SHARED ONCOGENIC MUTATIONS IN THE SUBVENTRICULAR ZONE AND GLIOBLASTOMA: GENETIC AND CLINICAL IMPLICATIONS
Authors: Lee Joo Ho , Kim Hyun Jung , Yoo Jihwan , Shim Jin Kyoung , Kim Eui-Hyun , Chang Jong Hee , Park Jung Won , Li Xue , Lee Jeong Ho , Kang Seok-Gu
Published: November 2024

The subventricular zone (SVZ), a neurogenic niche in the adult brain, is suspected to harbor neural stem cells (NSCs) that can acquire cancer-driving mutations and give rise to glioblastoma (GBM). Nevertheless, the corroborating genetic data are restricted to a small patient cohort. This study aimed to validate the presence of low-level oncogenic mutations in the SVZ of GBM patients and assess their clinical implications.. We performed deep hybrid capture sequencing of 15 GBM-associated genes and TERT promoter amplicon sequencing on triple-matched samples from the SVZ, primary tumor, and blood of 60 GBM patients. Approximately 62% of patients (40 of 61 patients) showed shared oncogenic mutations between the tumor and tumor-free SVZ, including TERT promoter, PTEN, and TP53. While shared mutations did not affect overall clinical profiles, TERT promoter mutations were significantly enriched in the shared group (94.9% of patients, p ≤ 0.001). RNA sequencing revealed upregulation of proliferation-related genes in tumors with shared SVZ mutations, and these patients had worse progression-free and overall survival (p = 0.038 and 0.031, respectively). This study provides the largest-scale genetic validation of the SVZ as a potential cellular origin of GBM, highlighting the distinct genetic and clinical features associated with shared oncogenic mutations. These findings warrant further investigation into the role of SVZ mutations in GBM genesis and their potential as therapeutic targets.
STEM-08. LIPID SATURATION HOMEOSTASIS PRESENTS A TARGETABLE VULNERABILITY IN MYC-AMPLIFIED GROUP 3 MEDULLOBLASTOMA
Authors: Custers Stefan
Published: November 2024

Medulloblastoma (MB) is the most common malignant pediatric brain cancer, originating from the cerebellum. Despite advancements in standard of care (SoC), MB remains fatal for 30% of patients. Tumor relapse, spinal metastasis and treatment resistance are the most prevalent in MYC-driven Group 3 MB (G3-MB). Patients surviving SoC are faced with life-long neurocognitive and neurodevelopmental deficits. These issues highlight the urgent need for improved treatment modalities. Reprogramming of cellular lipid metabolism is an emerging hallmark of cancer and may yield novel cancer-specific therapeutic options. Here we explore the lipidome of both G3-MB and its proposed cell of origin, human neural stem cells (hNSCs) by comparing untargeted lipidomics using Liquid-Chromatography-Mass Spectrometry (LC-MS). Comparative analyses revealed a differential abundance of distinct lipid species in G3-MB, with an overall reduced saturation level of fatty acids (FAs). These findings implicate the de novo lipid synthesis (DNL) pathway. We identified the enzymes involved in DNL to be essential for MB survival in our genome-wide CRISPR KO screen. Additionally, mRNA expression of the DNL enzymes increases at relapse in our SoC-adapted murine patient-derived xenograft (PDX) model. Pharmacological and genetic targeting of the DNL enzyme Stearoyl-CoA Desaturase 1 (SCD1) selectively targets G3-MB. Furthermore, small molecule treatment of SCD1 demonstrates efficacy against G3-MB PDX models in vivo. We identified SCD expression as a prognostic marker in Group 3 and 4 MB patients and identified possible pathways for MB treatment. Overall, these findings indicate that SCD1 is a potent target for the treatment of G3-MB.
STEM-09. A GROUP 3 MEDULLOBLASTOMA STEM CELL PROGRAM IS MAINTAINED BY OTX2-MEDIATED ALTERNATIVE SPLICING
Authors: Saulnier Olivier , Zagozewski Jamie , Liang Lisa , Hendrikse Liam , Layug Paul , Gordon Victor , Aldinger Kimberly , Haldipur Parthiv , Borlase Stephanie , Coudière-Morrison Ludivine , Cai Ting , Martell Emma , Gonzales Naomi , Palidwor Gareth , Porter Christopher , Richard Stephane , Sharif Tanveer , Millen Kathleen , Doble Brad , Taylor Michael , Werbowetski-Ogilvie Tamra
Published: November 2024

Group 3 medulloblastomas (MBs) are highly metastatic pediatric brain tumors with limited therapeutic options. The transcription factor orthodenticle homeobox 2 (OTX2) is a known driver and molecular hallmark of Group 3 MB. We previously demonstrated that OTX2 regulates Group 3 MB cell fate decisions that favor self-renewal or stemness and the retention of a primitive cerebellar rhombic lip signature. Here, we show that OTX2-regulated alternative splicing (AS) is a major driver of Group 3 MB progression. Surprisingly, the functional role of post-transcriptional events, such as AS, in Group 3 MB development has never been explored. This gene regulatory layer represents an untapped source of therapeutic targets. Using a combination of TurboID, RNA-sequencing and single cell RNA-seq, we characterized the Group 3 primary MB AS landscape with a focus on genes that control MB stem cells. OTX2 associates with the multimeric Large Assembly of Splicing Regulators (LASR) complex through protein-protein interactions and can directly or indirectly bind RNA. Together, OTX2 and LASR complex proteins oversee a pro-tumorigenic splicing program that is mirrored in the human cerebellar rhombic lip origins and is associated with Group 3γ MBs that exhibit the worst prognosis. Among our core set of OTX2-regulated spliced genes, periphilin 1 (PPHLN1) is expressed in the most primitive cerebellar rhombic lip stem cells, and mimicking PPHLN1 AS by pre-treating cells with a splice blocking antisense morpholino reduces tumor growth while increasing survival in vivo. We propose that OTX2-mediated AS is a key determinant of cell fate decisions favoring the maintenance of the stem cell state. Targeting transcription factors like OTX2 is notoriously difficult; thus, our work offers fresh opportunities to exploit MB-specific AS events therapeutically to abrogate tumor progression.
STEM-17. THE UROKINASE RECEPTOR AS A NOVEL IMMUNOTHERAPEUTIC TARGET IN BRAIN CANCERS
Authors: Maich William , Shaikh Muhammad Vaseem , Puri Anish , Mobilio Daniel , Ananda Alisha , Venugopal Chitra , Rossotti Martin , Mikolajewicz Nick , Chokshi Chirayu , Salim Sabra , Savage Neil , Kislinger Thomas , Henry Kevin , Singh Sheila
Published: November 2024

Glioblastoma (GBM) is the common malignant brain tumor in adults, accounting for approximately 15% of all CNS tumors, and 48.6% of malignant brain tumors, with a median survival of approximately 15 months. GBM is characterized by extensive inter- and intra-tumoral heterogeneity and an extremely immunosuppressive tumor microenvironment. Following Standard-of-Care surgical resection and chemoradiotherapy, patients inevitably relapse, at which point few therapeutic avenues exist, owing in part due to a lack of clinically relevant targets. Data from our target identification pipeline shows the urokinase plasminogen activator receptor (uPAR) is significantly upregulated at recurrence on putative GBM brain tumor initiating cells (BTICs), which are believed to drive de novo tumor formation, recurrence, and therapeutic resistance. uPAR plays an important role in the plasminogen activation system, and in the context of cancer, has been implicated in numerous pro-tumorigenic processes such as invasion, proliferation, and therapy resistance. We used CRISPR-Cas9 to genetically delete uPAR from our in-house patient-derived GBM cell lines, and found that knockout of uPAR in recurrent GBM cells significantly reduces various functional characteristics of BTICs in vitro. In our patient-derived mouse model of GBM, we found that knockout of uPAR significantly increases survival, and decreases tumor burden. Further, we generated novel anti-uPAR single domain antibodies (sdAbs) which specifically and efficiently bind uPAR at low nanomolar concentrations in vitro. We developed anti-uPAR CAR Ts using the binder sequence of the sdAbs, which showed potent cytotoxicity in vitro, and drastically reduced tumor burden and extended survival in vivo. Further, we identified uPAR as being highly expressed on brain metastases from multiple origins (lung-to-brain, melanoma-to-brain, etc.), and demonstrate that anti-uPAR CAR Ts effectively kill brain metastases in vitro, and significantly extend survival using in vivo brain metastasis models. From this work we believe uPAR to be a clinically relevant target in both recurrent GBM and brain metastases, and investigation into therapeutic strategies targeting uPAR-positive brain cancers should be explored further.
CSIG-06. BRAF GERMLINE MUTATIONS AND PREDISPOSITION TO BRAIN TUMORS
Authors: Abdelmoula Nouha Bouayed , Abdelmoula Balkiss , Smoui Walid , Trigui Khaled , Louati Rim
Published: November 2024

We report on two BRAF-mutated children and discuss genetic counseling regarding predisposition to brain tumors. Molecular analysis of the PTPN11 gene and twelve other genes in the RAS-MAPK pathway was carried out in a series of 54 dysmorphic patients with suspected Rasopathies. Two heterozygous BRAF germline mutations were detected in two 7-year-old girls, at exon 6 and 12 respectively. Both patients had the distinctive facial appearance of cardio-facio-cutaneous syndrome (CFC) type 1. Patients with CFC are rare and characterized by phenotypic and genetic heterogeneity, with overlaps with Noonan syndrome. While nearly 75% of CFC cases have germline BRAF mutations, the frequency of BRAF mutations is inferior in Noonan and LEOPARD syndromes. BRAF mutations in CFC are often found in the cysteine-rich domain of the BRAF protein (exons 6, 11, 12, 13, 14, 15 and 16). Conversely, somatic BRAF mutations are more common, grouped into classes according to their kinase activity level, and have been associated with a variety of malignancies, including pediatric and adult brain tumors (low- and high-grade gliomas, glioblastomas and low-grade astrocytomas). BRAF V600E is the most common somatic mutation, but other mutations are currently being identified. Many of these mutations are within the kinase domain, while others are located across the gene and have less well-understood functional consequences. Germinal V600E mutation has been described once, in a CFC patient having a severe phenotype. Nevertheless, it seems that patients with germline BRAF mutations and gliomas have not yet been reported. Given the rarity of CFC, it is unclear whether there is a high risk of brain tumors. Further molecular studies will enable us to refine recommendations for the prevention, monitoring and care of people with germline BRAF mutations, given the success of BRAF inhibitors in certain cancers, with encouraging results in gliomas.