bluuebunny/crossref_metadata_2025 huggingface dataset:
CNSC-04. UNDERSTANDING PEDIATRIC BRAIN TUMOR CHEMOTHERAPY INDUCED LONG-TERM DEFICITS IN HIGH-ORDER NEUROCOGNITIVE AND SENSORIMOTOR FUNCTION
Authors: Singh Anand , Harris Momo , Mahalingam Rajasekaran , Ban Kechen , Bertrand Renae , Zimbwa Shungu , Kasm Khalil Ali Ahmad , Pan Yuan
Published: November 2024

Because of major advancements in cancer treatment especially chemotherapy, 85% of children with cancer are predicted to survive for 5 years or more. However, chemotherapy can cause long-term health problems when childhood cancer survivors enter adulthood (known as late effects). The neurocognitive features of these late effects (chemobrain) include trouble in concentrating, memorizing, and decreased processing speed, and results in lower IQ and academic achievement, poor hand-eye coordination, and slower development over time. Despite such a negative impact on the quality of life of cancer-surviving children, the mechanism is poorly understood and there is no FDA-approved drug to prevent or cure these side effects. To gain a better understanding of the mechanism underlying chemotherapy-induced cognitive impairments, we developed a pre-clinical model using carboplatin in juvenile mice to study long-term neurological defects. Carboplatin is commonly used chemotherapy drug in pediatric brain tumor patients. We have tested the capacity of different doses of carboplatin and its long-term effect on cognitive and sensorimotor function and performed single nuclear RNA sequencing (snRNAseq) of the hippocampus. Our preliminary data demonstrated dose-dependent deficits in executive and sensorimotor function 7-9 weeks after carboplatin administration in the mice of both sexes. snRNAseq of the hippocampus showed changes in the glial cell number as well as genes associated with oxidative phosphorylation and neurodegeneration at early and late time points. Bioenergetics using Seahorse in the brain synaptosomes revealed mitochondrial dysfunction in the form of decreased maximum respiratory capacity long after carboplatin treatment. This study established a preclinical model that can be leveraged to mechanistically understand the long-term neurocognitive side effects of brain tumor chemotherapy during childhood. Future studies will aim to identify potential targets to prevent and/or treat the neurotoxic effects of cancer treatment in pediatric patients.
CNSC-12. IMMUNOLOGICALLY TARGETING U1 MUTANT SHH MEDULLOBLASTOMA
Authors: Kameda Michelle , Zheng Rong , Ahmed Nabil , Cheng Chonghui , Taylor Michael
Published: November 2024

OBJECTIVES

Medulloblastoma (MB) is the most common malignant pediatric brain tumor representing a significant burden of morbidity and mortality in the US. MB is comprised of four subgroups: Wnt, Shh, Group 3, and Group 4. Shh tumors represent 25% of cases and subdivides into Shh-beta and Shh-gamma, Shh-alpha, and Shh-delta. Half of Shh MB carry an identical somatic point mutation in a non-coding small nuclear RNA (snRNA) called U1 (r.3A>G) which is found in 97% of Shh-d tumors, and in most Shh-alpha tumors with TP53 mutations. Current therapies for patients with TP53 and U1 mutant Shh-alpha MB observe rare survivors, and adult Shh-delta patients continue to experience significant morbidity and mortality calling for urgent prioritization of these tumors for targeted therapy.

METHODS

Cryptic exons were identified in both Shh-delta U1 snRNA mutant samples and Shh-delta U1 wildtype (WT) samples using CryEx pipeline. In-house scripts were utilized for selecting for cryptic exons that are uniquely expressed in Shh-delta U1 snRNA mutant compared to wildtype (WT) samples.

RESULTS

Analyzing 180 Shh MB RNA-seq samples, we identified 23% Shh-alpha, no Shh-beta, 97% of Shh-delta and 3% Shh-gamma harbored the U1 mutation. The splicing landscape was then interrogated comparing Shh-delta U1 snRNA mutant samples to WT samples. Expressed exons were filtered to exclude known exons to identify novel or cryptic exons. To select for Shh-delta U1 snRNA mutant induced cryptic exons, CryEx arising from introns, not identified in Shh-delta U1 WT and included >10% of their inclusion rates measured by percent spliced in (PSI) in Shh-delta U1 snRNA mutant samples were filtered. Of the middle CryEx, we identified 43,188 that were U1 mutant induced. Further filtering for cell surface Middle CryEx, three of the 75 middle CryEx overlapped.

CONCLUSION

The PTCH1 neoantigen formed from the CryEx insertion translates a protein that is unique to the tumor cells (i.e., not in normal tissue) was identified as a juxtamembrane for therapeutic drug discovery.
CNSC-13. CROSSTALK BETWEEN SENSORY NEURONAL ACTIVITY AND TUMOR CELLS PROMOTES MALIGNANCY AND CANCER PAIN
Authors: Ahmad Kasm Khalil Ali , Ban Kechen , Irshad Khushboo , Cortez Ibdanelo , Shen Cheng-En , Singh Anand , Rasheed Sami Mohd , Willcox Kendal , Grace Peter M , Hirbe Angela , Shepherd Andrew J , Pan Yuan
Published: November 2024

BACKGROUND

Nerve infiltration of solid tumors is associated with poor prognosis in multiple cancer types. Understanding the role of neuronal activity in cancer progression offers innovative approaches for treating malignancies and cancer-associated neurological issues such as pain. Pain perception is mediated by the activity of peripheral sensory neurons. Many cancer types induce pain, and sensory innervation could support tumor growth, raising the interesting hypothesis that cancer pain-associated neuronal activity promotes malignancies. Our study aims to test the hypothesis using malignant peripheral nerve sheath tumor (MPNST) as the experimental platform.

METHODS

in vivo allograft models were established by implanting mouse MPNST cells into the sciatic nerves of male and female mice, followed by performing pain behavior assays (von Frey, Hargreaves, and conditioned place preference tests) and tumor growth measurements. Primary mouse dorsal root ganglion (DRG) sensory neuron cultures were prepared for calcium imaging and neuron-tumor co-culture experiments.

RESULTS

MPNST tumor-bearing mice exhibited hypersensitivity to noxious and non-noxious stimuli (evoked pain) and ongoing pain, compared to the sham controls. MPNST-conditioned media increased intracellular calcium concentration and ATF3 (indicator for nerve injury/stress) expression in primary sensory neuron culture, suggesting that MPNST tumor cell secretory factors may induce pain by triggering sensory neuron injury/stress responses that increase sensory neuron activity/sensitivity. Reciprocally, we found that stimulation of sensory neuron activity accelerates MPNST tumor growth. The conditioned media from stimulated sensory neurons increased tumor proliferation (EdU assay) in vitro, suggesting that sensory neuron activity-induced paracrine factors increase MPNST cell growth.

CONCLUSIONS

MPNST is a devastating cancer that grows within peripheral nerves which induce intractable pain. Our findings demonstrate a feedforward cycle where the cancer cells induce sensory neuron hypersensitivity/hyperactivity (pain) which in turn further accelerates tumor growth. Future studies will identify the molecular mechanisms underlying this crosstalk between MPNST and sensory neuron activity.
CNSC-16. ASSOCIATION BETWEEN RESTING-STATE-NETWORK FUNCTIONAL CONNECTIVITY AND SURVIVAL IN RECURRENT GLIOMAS DIAGNOSED USING FET PET
Authors: Friedrich Michel , Werner Jan-Michael , Steinbach Joachim P , Sabel Michael , Herrlinger Ulrich , Piroth Marc , Stoffels Gabriele , Filss Christian P , Lohmann Philipp , Shah Nadim J , Ruge Maximilian I , Mottaghy Felix M , Goldbrunner Roland , Langen Karl-Josef , Fink Gereon R , Kocher Martin , Galldiks Norbert
Published: November 2024

BACKGROUND

Functional connectivity between glioma-infiltrated brain tissue and remote cortical regions has been linked to overall survival (OS) in patients with newly diagnosed glioblastoma. We studied the association of functional connectivity between tumor and resting-state networks and OS in patients with recurrent gliomas.

PATIENTS AND METHODS

The study included 82 patients (26-81 years; median ECOG performance score, 0) with recurrent gliomas (grade 4 glioblastoma, n=57; grade 3 and 4 astrocytoma, n=12; grade 2 and 3 oligodendroglioma, n=13) who had undergone first-line therapy. Diagnosis of recurrence was confirmed by amino acid PET using the tracer O-(2-[18F]-fluoroethyl)-L-tyrosine (FET). FET PET and resting-state functional MRI were simultaneously acquired on a 3T hybrid PET/MR scanner. We performed a seed-based dual regression analysis to determine the functional connectivity between metabolically active tumors and seven canonical resting state networks.

RESULTS

Average functional connectivity was highest in oligodendrogliomas (z-score, 6.9±1.9) and was inversely related to the tumor grade (p=0.031). Univariate Cox regression analysis revealed a significant (p<0.05) positive association between OS and tumor connectivity with the visual, somatomotor, and dorsal attention networks. Subsequent stepwise multivariate Cox regression analysis refined this association to the dorsal attention network alone (HR, 0.88; 95% CI, 0.80-0.97; p=0.007). Patients with the highest functional connectivity (z-score>8.3, n=21) had a median OS of 31.4 months, while those with the lowest functional connectivity (z-score<4.3, n=21) had 10.6 months. Functional connectivity between tumors and the dorsal attention network showed an independent association with OS (HR, 0.90; 95% CI, 0.81-0.99; p=0.033) in a multivariate model, including various prognostic factors.

CONCLUSION

Recurrent gliomas exhibit significant functional connectivity to most of the major known resting-state networks, highest in oligodendrogliomas. The data suggest that high functional connectivity between the tumor and the dorsal attention network is an independent prognostic factor for improved OS.
CNSC-25. CONCURRENT IMMUNE CHECKPOINT BLOCKADE ENHANCES THE SURVIVAL BENEFIT OF CLINICALLY RELEVANT MAPK PATHWAY INHIBITORS IN A T CELL-DEPENDENT MANNER
Authors: Xing Yao Lulu , Park Jong-Whi , Grossauer Stefan , Panovska Dena , Bui Brandon , Morales Daniella , Nirschl Jeffrey , Feng Zhi-Ping , Anderson Wes , Levy Jean Mulcahy , Schreck Karisa , Prolo Laura , Hambardzymyan Dolores , Petritsch Claudia
Published: November 2024

BACKGROUND

Despite the availability of targeted therapies, gliomas carrying the BRAFV600E mutation remain challenging to treat. Combined pharmacologic BRAFV600E and MEK inhibition is clinically used in patients with BRAFV600E mutant gliomas, but primary and acquired resistance is reported in ~70% of high-grade glioma patients.

OBJECTIVES

To gain mechanistic insights into therapy adaptation and escape for developing combination therapies that enhance clinical effects of combined BRAFV600E inhibition with Dabrafenib and MEK inhibition with Trametinib (BRAFi+MEKi) in high-grade gliomas.

APPROACH

Patients’ pre- and post-treatment glioma tissues, patient-derived and mouse cell lines, and two novel immunocompetent mouse models for BRAFV600E mutant high-grade gliomas were analyzed for the effect of BRAFi+MEKi using a range of techniques including bulk and single-cell RNA sequencing, immunofluorescence staining, flow cytometry, and mass cytometry.

RESULTS

We present new data showing that the BRAFi+MEKi combination significantly reduced glioma cell viability while inducing glial differentiation programs, potentially associated with programmed death receptor (PD-1) signaling. This suggests a profound shift in the glioma cell differentiation state that is linked to an inclination toward T cell inhibition. This prompted us to combine BRAFi+MEKi with immune checkpoint inhibitors targeting PD-L1 and CTLA-4, which significantly decreased T cell inhibition. Furthermore, from mouse studies, this combination therapy conferred a survival benefit over single BRAFi+MEKi combination therapy alone. Additionally, BRAFi+MEKi treatment triggered an interferon-gamma response, indicative of cytotoxicity, and enhanced the expression of MHC molecules associated with antigen presentation, only in drug-sensitive but not drug-resistant gliomas. The lack of improved therapeutic efficacy of immune checkpoint blockade in athymic mice, which lack T cells, emphasized the critical role of T cell activity in driving the success of the combination treatment.

CLINICAL IMPACT

Our preclinical findings highlight the potential of concurrent BRAFi+MEKi treatment and immune checkpoint blockade for overcoming therapy resistance in BRAF mutant high-grade glioma patients.
CNSC-27. INTRATUMORAL CANCER CELL NETWORKS IN BRAIN METASTASES
Authors: Olshausen Niels , Hebach Nils R , Schlag Joana S , Thommek Calvin , Yang Yvonne , Hoffmann Dirk C , Mayer Chanté , Westphal Dana , Breckwoldt Michael O , Wick Wolfgang , Winkler Frank , Karreman Matthia A
Published: November 2024

Recently, we have shown that primary brain tumors form highly organized, small-world scale-free networks, reminiscent of early networks in neurodevelopment and highly resistant to therapy. Such putative cancer-cell intrinsic neural mechanisms are becoming an increasing focus in the field of Cancer Neuroscience, but it has not yet been shown whether tumors of non-CNS origin also have the ability to form multicellular networks which sustain proliferative signaling and increase resistance to therapy. We observed synchronized calcium activity using longitudinal microscopy both in vivo and in vitro that were reminiscent of gap junction coupled networks. Indeed, dye transfer experiments verified functional coupling of brain metastases cells in vitro. Similarly, inhibition of gap junctions with different pharmacological agents significantly reduced calcium oscillations and tumour proliferation in vitro. Furthermore, gap junctions are significantly upregulated in brain-tropic sublines compared to parental cells. To understand the functional relevance of these gap-junction coupled tumor cell networks, we performed bulk RNA-Sequencing of two melanoma metastasis models in monoculture under gap junction inhibition and control: We observed reduced calcium communication and a concordant downregulation of neurodevelopmental and synaptic pathways within the tumor cells upon network disconnection, highlighting a potential recapitulation of neural-like features in metastases to the brain. To investigate the therapeutic potential of targeting these networks, we treated mice with brain metastases with two brain-penetrant gap junction blockers and observed significantly reduced tumor burden. Finally, we investigated the presence of heterotypic networks between brain metastases cells and the brain microenvironment with our SR101 dye transfer pipeline. Contrary to our findings in primary brain tumors, no gap junction connections to cells of the brain microenvironment in those models with reduced tumor growth upon network inhibition could be detected, supporting a cancer cell intrinsic gap junction mediated network and highlighting a selectivity of these homogenous tumor networks and potential therapeutic vulnerability.
CNSC-32. CHARACTERISTIC ANALYSIS OF SPREAD AND METASTASIS OF HIGH-GRADE GLIOMA
Authors: Li Shaoqun , Lai Mingya , Wang Lichao , Zhang Yangqiong , Ye Minting , Li Juan , Ai Ruyu , Cai Linbo
Published: November 2024

OBJECT

Exploring the clinical characteristics of spread and metastasis of high-grade glioma is helpful for clinicians to further understand high-grade glioma, optimize clinical decision-making, and make treatment plans.

METHOD

Clinical data of patients diagnosed with WHO Grade 4 glioma with spread and metastasis in the course of disease in Guangdong Sanjiu Brain Hospital from January 1, 2017 to December 31, 2020 were collected and analyzed.

RESULTS

93 patients were included in the analysis, 59 males and 34 females, median age of 42 years (3-71 years). Tumors were located supratentorial in 78 patients (83.9%). Most patients (70, 75.3%) had tumors adjacent to the ventricular system. 28 patients (30.1%) had tumor spread at first diagnosis. All patients received surgical at first diagnosis, including total resection in 36 cases (38.7%), partial resection in 42 cases (45.2%), and biopsy in 15 cases (16.1%). In 48 patients (51.6%), ventricles were opened during operation. 69 cases (74.2%) were pathologically diagnosed with glioblastoma, 81 cases (92.0%) were IDH wild-type. MRI findings of dissemination were linear in 50.0% (46 cases), nodular type in 25.0% (23 cases), mixed type in 25.0% (23 cases), and the remaining 1 case was undetermined. Cerebrospinal fluid examination was performed in 37 cases, which 11 cases were cytological positive (29.7%). Median OS for patients with initial dissemination was 338 days. Of the 68 patients developed transmission after treatment, median OS fro initial diagnosis to transmission was 254 days, the overall median OS was 409 days. The overall median OS for all patients was 403 days. The median OS of newly diagnosed patients with tumor spread was lower than that of patients with tumor spread after treatment, but there was no statistical difference (p=0.05).

CONCLUSION

Most high-grade glioma patients develop tumor spread within 1 year, and these patients have unique clinical characteristics. The positive rate of cerebrospinal fluid tumor cells is low, MRI imaging is still the main diagnostic option.
CNSC-41. DABRAFENIB AND TRAMETINIB AS A PROMISING TREATMENT OPTION FOR PEDIATRIC POPULATION WITH LOW-GRADE GLIOMAS THAT HAVE BRAF V600E MUTATION:A BREAKTHROUGH IN THE FIELD OF NEURO- ONCOLOGY
Authors: Mughal Zaib Un Nisa , Ahmad Tagwa Kalool Fadlalla , Haseeb Abdul , Shafique Muhammad Ashir , Ahmdon Ola Elhadi Abbas , Mahgoub Abdulhadi Mohamed Ahmed
Published: November 2024

Two-thirds of all pediatric malignant central nervous tumors, including high-grade (glioblastoma, anaplastic astrocytoma) and low-grade (ganglioglioma, pilocytic astrocytoma) carcinomas, are gliomas. Low-grade glioma(LGG) exhibits genetic alterations caused by the BRAF kinase mutation, such as replacing glutamic acid (E) in place of valine (V) at the 600 positions, known as the V600E point mutation. Pediatric low-grade gliomas (PLGGs) also comprise around one-third of juvenile brain tumors and are the most frequent central nervous system tumors. Patients were randomized 2:1 to dabrafenib plus trametinib (D+T) or carboplatin plus vincristine (C+V). Where possible, complete surgical removal is the mainstay of treatment for progressing or symptomatic PLGG.Radiation therapy has historically been used to treat PLGG in both up-front and salvage scenarios. To delay or avoid the necessity for radiation therapy in young children with advancing or incompletely resected PLGG, chemotherapy was created in 1980. On March 16, 2023, the Food and Drug Administration approved the use of trametinib (Mekinist, Novartis) with dabrafenib (Tafinlar, Novartis) in pediatric patients suffering from low-grade glioma (LGG) who require systemic therapy and are at least one year old. Nevertheless, early-stage clinical trials have produced encouraging results that may revolutionize the treatment of LGG in the near future.
CNSC-43. NEUROTRANSMITTER DEPENDENCY UNDERLIES TUMOR GROWTH IN HUMANIZED PEDIATRIC LOW-GRADE GLIOMA MODELS
Authors: Anastasaki Corina , Barakat Rasha , Mu Rui , Koleske Joshua P , Kernan Chloe M , Gao Yunqing , Cobb Olivia M , Gardner Corrine , Shu Hongjin , Nair Lakshmi Ramachandran , Dahiya Sonika , Eberhart Charles G , Phillips Joanna J , Mennerick Steven J , Strahle Jennifer M , Rodriguez Fausto J , Gutmann David H
Published: November 2024

Brain tumors arise in close association with neurons, suggesting that these non-neoplastic cells may be critical stromal drivers of brain tumor initiation and growth. Previously, we have shown that murine low-grade optic glioma formation and progression in the setting of Neurofibromatosis type 1 (NF1) is dictated by neurons and neuronal activity. In these studies, these neuronal dependencies reflected neuronal activity-driven enzymatic cleavage of a growth factor (neuroligin-3) from oligodendrocyte precursors cells (tumor initiation) or neuronal production of a paracrine factor to stimulate T cell support of optic glioma growth (tumor progression). Since neurons typically communicate with other neurons through neurotransmitters, we sought to explore the possibility that neurotransmitters operate to modulate low-grade glioma growth using humanized mouse models of pilocytic astrocytoma (PA). Leveraging single cell RNA sequencing of three independent sets of pediatric PAs, we identified neurotransmitter pathway enrichment in the tumor cells. This neurotransmitter pathway enrichment reflected aberrant expression of specific neurotransmitter receptors, which we confirmed in three independently generated PA tissue microarrays and in five distinct primary PA cell lines grown in vitro. Moreover, this aberrant neurotransmitter receptor expression established differential neurotransmitter PA growth dependencies in vitro. Importantly, interruption of neurotransmitter signaling in human PA xenografts attenuated tumor growth and ERK activation in Rag1-/- mice in vivo. Finally, we discovered crosstalk between neurotransmitter receptor and receptor tyrosine kinase signaling that revealed another target for therapeutic inhibition. Taken together, these findings elucidate a previously unknown neurotransmitter PA growth dependency amenable to therapeutic targeting.
CNSC-46. GLIOBLASTOMA INITIATION, MIGRATION, AND CELL TYPES ARE REGULATED BY CORE BHLH TRANSCRIPTION FACTORS ASCL1 AND OLIG2
Authors: Myers Bianca , Brayer Kathryn , Paez-Beltran Luis , Keith Matthew , Suzuki Hideaki , New Jessie , Anderson Rebekka , Lo Yunee , Mertz Conner , Kollipara Rahul , Borromeo Mark , Lu Richard , Bachoo Robert , Johnson Jane , Vue Tou Yia
Published: November 2024

Glioblastomas (GBMs) are highly aggressive, infiltrative, and heterogeneous brain tumors driven by complex genetic alterations. The neurodevelopmental transcription factors ASCL1 and OLIG2 are highly co-expressed in GBMs. However, their combinatorial roles in regulating the hierarchy and heterogeneity of GBM cells are unknown. Here, we show that induction of somatic mutations in neural progenitor cells lead to the dysregulation of ASCL1 and OLIG2, which then function redundantly and are required for brain tumor formation in a mouse model of GBM. Subsequently, the binding of ASCL1 and OLIG2 to each other’s loci and to downstream target genes then determine the cell types and degree of migration of tumor cells. Notably, single-cell RNA sequencing (scRNA-seq) reveals that a high level of ASCL1 is key in promoting neural stem cell (NSC)/astrocyte-like tumor cell types, which are highly proliferative, migratory, and are marked by upregulation of ribosomal protein, oxidative phosphorylation, cancer metastasis, and therapeutic resistance genes.
CNSC-49. ELUCIDATING THERAPEUTIC POTENTIAL OF USP1 INHIBITION IN DIFFUSE MIDLINE GLIOMAS
Authors: Yadav Monika , Klinestiver Adora , Gibson Garrett , Faisal Syed M , Messinger Dana , Koschmann Carl , Yadav Viveka Nand
Published: November 2024

Diffuse midline gliomas (DMGs) are aggressive childhood brain tumors with the H3K27M mutation in the H3F3A or H3C2 gene. Despite treatment advances, radiotherapy is the only viable option, but 99% of patients die within 1.5-2 years. Therefore, there is an urgent need to identify potential novel therapeutic targets for the treatment of DMGs. Ubiquitin-specific protease 1 (USP1) is a key deubiquitinating enzyme involved in genome integrity, cell cycle regulation, and cell homeostasis. USP1 is overexpressed in various cancers, including gliomas, is linked to poor prognosis. It promotes glioma stem cell (GSC) self-renewal and radio-resistance by regulating ID1 and CHEK1. Our recent findings show that ID1 is crucial for DMG invasion and migration. Inhibiting USP1 suppresses malignant growth, enhances radiation sensitivity, and improves chemotherapy response, highlighting its potential for combined therapies. However, USP1’s role in DMGs and its feasibility as a therapeutic target remain poorly understood. In this study, we investigated USP1 in DMGs for the first time. RNA sequencing revealed high USP1 expression in DMG patient samples and cell lines, directly linked to the H3K27M mutation. Correcting this mutation reduced USP1 expression in DMG cell lines. Pharmacologic inhibition of USP1 with the specific inhibitor SJB3-019A significantly reduced DMG cell proliferation, triggered apoptosis, and altered cell cycle profile. SJB3-019A-mediated USP1 inhibition decreases migration and invasion in multiple patient-derived DMG cell lines. Additional in vitro experiments revealed that USP1 inhibition leads to a significant decrease in the expression of ID1 and pAKT, suggesting the ID1/AKT pathway as a potential mechanism underlying the observed effects. H3K27M-mediated activation of USP1 in DMG is a promising therapeutic target, with inhibition by SJB3-019A reducing tumor aggressiveness by inhibiting invasion and migration. We will next assess SJB3-019A’s efficacy in vivo using genetically engineered isogenic mouse models (GEMM) with DNp53/PDGFRA/H3.3K27M (PPK) alterations and evaluate USP1 inhibition combined with radiation therapy as a potential radiosensitizer in DMGs.
CNSC-58. BIOPROCESSING OF VIABLE SURGICAL PEDIATRIC BRAIN TUMOR SPECIMENS FOR GENOME-GUIDED PERSONALIZED DRUG TESTING
Authors: Nasajpour Emon , Tran Caitlynn , Garcia Cesar , Xing Lulu , Lyle Geoff , Guinle Maria Isabel Barros , Bagley Bryce , Mahaney Kelly , Vogel Hannes , Learned Katrina , Vaske Olena , Grant Gerald , Prolo Laura , Maher Cormac , Petritsch Claudia
Published: November 2024

Novel treatment approaches are urgently needed for pediatric central nervous system (CNS) tumors as they are the leading cause of cancer-related deaths in children. A lack of research materials impedes progress towards developing such therapies. Although various brain cancer biobanks exist, these rarely store viable patient-derived tissue and cells for live cell analyses, including cell fate assays and testing for drug sensitivities. We propose that a biorepository of viable cell dissociates and tissue broadly representing CNS tumor entities overcomes these limitations. From a combination of molecular diagnoses and histopathologic assessment of over 120 samples collected, we generated a biorepository of roughly 35 distinct entities of pediatric CNS tumors in our Stanford neuro-bioprocessing cohort. Based on the Central Brain Tumor Registry of the United States, the proportion of subtypes represented in our cohort match that of the general population with exceptions. We established a standardized bioprocessing pipeline that can be used as a template for tissue collection and model development in the broader disease context and for multiple downstream applications. Our emphasis on cryostorage of viable cells and tissue facilitates ad hoc live cell analyses. In addition to gaining a better understanding of tumor pathophysiology, we attempted a rapid bed-to-bench-to-bedside approach using comparative RNA expression profile analyses in an individual patient’s pilocytic astrocytoma. Novel drug targets were identified by analyzing RNA transcripts that are highly expressed (outliers) compared with a compendium of 12,747 brain and non-brain tumor samples. We validated outliers as drug targets using acute cell isolates, and identified a novel target in recurrent low-grade glioma. These studies illustrate that biobanking of viable patient-derived material enables developing personalized therapies with the goal of improving patient outcomes. As demonstrated here, patient-derived acute cell isolates facilitate identifying drug vulnerability, creating an opportunity for more personalized treatment of patients with CNS tumors.
CNSC-70. THE ROLE OF MAP4K4 IN TUMOR CELL INVASION OBSERVED IN A 3D IN VITRO MODEL OF PEDIATRIC GLIOBLASTOMA
Authors: Garcia Cesar , Nettnin Ella , Arana Sophia , Nguyen Thien , Guinle Maria Isabel Barros , Wilson Christy , Petritsch Claudia K , Bassik Michael C , Prolo Laura M
Published: November 2024

Several CNS tumors such as pediatric glioblastoma (pGBM), diffuse midline glioma (DMG), and medulloblastoma (MB) are characterized by local invasive spread and dissemination of tumor cells into surrounding brain tissue. As identified by our group in a genome-wide CRISPR screen and several others, MAP4K4 is a mediator of cell invasion in several cancers, including glioblastoma and medulloblastoma. Recently, we validated the pro-invasive role of MAP4K4 in a panel of pGBM cell lines. To further validate this finding in the context of pGBM cellular invasion, we performed 3D Matrigel timelapse invasion assays. We performed single- and multi-spheroid encapsulation to track spheroid invasion and cell-to-cell interactions between multiple spheroids. Tumor spheroids were cultured in a round-bottom, non-adherent well plate encapsulated in a Matrigel matrix and treated with a MAP4K4 small molecule inhibitor (PF06260933 dihydrochloride) or had a MAP4K4 knockout performed with Cas9 editing. Cell invasion was recorded over 72 hours and three-dimensional structures were stained for actin and imaged 10 days post-initial seeding. We show that MAP4K4 KO (p ~ 0.00033), small-molecule inhibition in the presence of a TGFB receptor agonist (SRI-011381), (p ~ 0.001) and with drug alone (p ~ 0.013) decreased spheroid invasion and prevented single-cell invasion of pGBM cells (SF188) into the matrix. More surprisingly, abrogation of MAP4K4 prevented individual spheroids in a multi-spheroid co-culture, from forming integrated glioma networks through the formation of tube-like structures in the matrix. Based on our initial findings, it appears that MAP4K4 is necessary for single-cell invasion into a three-dimensional matrix. It also appears that MAP4K4 is required for cell-to-cell connections to form between spheroids in the 3D environment to allow for the formation of higher-ordered and spatially organized structures. Future directions include studying how MAP4K4 allows for the formation of glioma tumor networks in pediatric GBM.
STEM-02. INSIGHTS INTO STEM CELL THERAPIES FOR GLIOBLASTOMA: A SYSTEMATIC REVIEW
Authors: UWISHEMA Olivier
Published: November 2024

BACKGROUND

Glioblastoma accounts for the majority of gliomas, which are the most common brain tumors. Classified as grade 4 by the WHO, it carries a poor prognosis. Various stem cell therapies have been tested and analyzed for their efficacy in treating glioblastoma. The aim of this review is to examine the type, efficacy, and future considerations for different stem cell therapies in glioblastoma treatment.

MATERIALS AND METHODS

A literature review was conducted using Boolean operators in the form of Stem Cell Therapy AND Glioblastoma; Neural Stem Cells AND Glioblastoma; Cord Blood AND Glioblastoma. Electronic databases including Cochrane Library, PubMed, and Scopus were searched. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 Statement.

RESULTS

Targeting Cancer Stem Cells (CSCs) may be crucial for effective GBM treatment, as these cells are considered key drivers of tumor initiation, progression, and therapeutic resistance. Future research and clinical trials in this area are necessary to fully understand the potential of stem cells in combating glioblastoma.

CONCLUSIONS

While some stem cell therapies have shown promising initial results, it is important to consider the complexity of targeting Glioblastoma Stem Cells (GSCs), including malignant transformation, the heterogeneity of glioblastoma, and glioma-associated mesenchymal stem cells.
STEM-04. UNVEILING GLIOBLASTOMA ORIGIN-CELLS: ISOLATION AND CHARACTERIZATION FROM THE SUBVENTRICULAR ZONE
Authors: Choi Ran Joo , Jo Se-Young , Yeo Eunchae , Oh Hyeong-Cheol , Jo Euna , Shim Jin-Kyung , Kim Hyun Jung , Lee Joo Ho , Yoo Jihwan , Choi Seonah , Moon Ju-Hyung , Kim Eui-Hyun , Kim Se Hoon , Chang Jong Hee , Kim Hyun Seok , Lee Jeong Ho , Kim Hoon , Kim Sangwoo , Kang Seok-Gu
Published: November 2024

Glioblastoma (GBM) may originate from somatic mutations within the subventricular zone (SVZ). We investigated putative GBM origin-cells in the SVZ with somatic mutations implicated in GBM development. We hypothesized these origin-cells have unique properties compared to tumor-derived GBM tumorspheres (TSs). We isolated, characterized, and analyzed mouse transcriptomes of GBM origin-cells and GBM TSs, and sought to identify potential human GBM origin-cells within the SVZ. Using a mouse model with somatic mutations (Trp53/Pten/hEGFRvIII) induced within the SVZ, we demonstrated that mutated cells in the SVZ migrate to the cortex and form GBM. We isolated mouse GBM (mGBM) origin-cells from the SVZ and mGBM TSs from the tumors, comparing their characteristics, transcriptome, and tumorigenic potential upon orthotopic or SVZ injection. To identify potential human GBM origin-cells, single-nucleus RNA sequencing (snRNAseq) was performed on human GBM SVZ specimens. Our investigation revealed intriguing properties and distinct gene expression patterns in GBM origin-cells. mGBM origin-cells from the SVZ somatic mutation model demonstrated enhanced stemness and invasiveness compared to control SVZ cells. These cells exhibited site-specific tumorigenic capacity: cortical injection of mGBM origin-cells failed to induce tumor formation, while re-injection into the SVZ led to migration to the cortex and tumor development. RNA sequencing revealed significant gene expression differences between mGBM origin-cells and mGBM TSs despite similar mutation profiles, suggesting distinct identities. snRNAseq analysis of human GBM SVZ specimens (pathologically tumor-free) identified cells with chromosomal aberrations characteristic of early GBM development, including chromosome 7 gain / 10 loss. These findings suggest potential human GBM origin-cells within the SVZ. This study describes a distinct population of GBM origin-cells within the SVZ, different from tumor-derived cancer stem cells. These GBM origin-cells exhibit unique properties, including enhanced stemness and invasiveness, and display site-specific tumorigenic capacity, forming tumors only in the SVZ environment. Further research into the factors that cause GBM origin-cells in the SVZ to migrate and form tumors in the cortex is crucial.
STEM-10. NEURAL PROGENITOR CELL MARKERS IN IDH MUTANT AND IDHWT GLIOMAS
Authors: Alnahhas Iyad , Kayne Allison , Khan Mehak , Shi Wenyin
Published: November 2024

INTRODUCTION

Single-cell RNA sequencing (scRNA-seq) has helped to elucidate the cellular composition of cancer and its microenvironment. Recent scRNA-seq studies have highlighted the heterogeneity of glioblastoma (GBM). Moreover, single-cell GBM analyses have proposed resemblance of GBM cells to radial glia and outer radial glia, supporting the hypothesis that remnants of developmental tissue get reactivated in cancer. A recent study isolated neural progenitor cells (NPCs) from developing fetal human brain (gestational week 17–19) and classified NPCs based on their expression of THY1, CD24 and EGFR. Ventricular radial glia are THY1- CD24-EGFR+ whereas outer radial glia are THY1- CD24-EGFR-. Early neuron precursors are CD24+THY1-EGFR+ and glial progenitor cells (GPCs) are THY1+EGFR+. GPCs give rise to THY1+EGFR+PDGFRA+ pre-oligodendrocyte progenitor cells. The importance of EGFR in NPCs again highlights the resemblance to glioma.

METHODS

We aimed to apply the classification above to IDH mutant astrocytoma and oligodendroglioma as well as IDHwt glioblastoma samples. We used three publicly available datasets: Wang (paired 74 IDHwt primary and recurrent samples), Tirosh (6 primary oligodendroglioma samples) and Venteicher (10 primary IDH mutant astrocytoma).

RESULTS

In IDH mutant astrocytoma, 82.63% of cells express THY1+ (mostly EGFR+PDGFRA+) and 10.76% of cells are THY1-CD24-EGFR+. In oligodendroglioma, 75% of cells are THY1+ (mostly EGFR+PDGFRA+) and 12.07% are THY1-CD24-EGFR+. In IDHwt EGFR amplified primary GBM samples, 87.5% of cells are THY1-CD24-EGFR+. This percentage drops to 70.4% in the recurrent setting. THY1-CD24-EGFR- cells increase from 9.7% to 23.1% at recurrence. In IDHwt EGFRwt primary GBM samples, 48.6% of cells are THY1-CD24-EGFR+ and 44.15% are THY1-CD24-EGFR-. In the recurrent setting, 43.26% of cells are THY1-CD24-EGFR+ and 49.58% are THY1-CD24-EGFR-.

CONCLUSION

IDH mutant gliomas and IDHwt glioblastoma express different progenitor cell markers and may have a different cell of origin. THY1 is highly expressed in IDH mutant gliomas.
STEM-19. TARGETINGGIHCG LNCRNA IN GLIOBLASTOMA STEM CELLS: A POTENTIAL THERAPEUTIC STRATEGY
Authors: Hazra Rasmani
Published: November 2024

Glioblastoma multiforme (GBM) remains the most lethal and prevalent primary brain tumor worldwide. Despite advances in understanding its biology and multimodal therapy options, the overall prognosis for GBM patients remains bleak, primarily due to the high recurrence rate, which is intimately linked to tumor resistance against standard therapeutic interventions. Glioblastoma stem cells (GSCs) contribute to therapeutic resistance and cellular heterogeneity through their self-renewal properties and ability to adapt. Thus, identifying new molecular targets driving GBM progression is crucial for developing effective therapies. Recent advancements in genome biology have revealed that long non-coding RNAs (lncRNAs) play roles in various biological functions, and the dysregulation of numerous lncRNAs has been shown to be associated with specific cancers. To identify GSC-associated lncRNAs, a comprehensive analysis was performed using single-cell RNA sequencing datasets from GBM tumors, GBM organoids, GSC-enriched GBM tumors, as well as normal human brain samples. A chromatin-enriched lncRNA, GIHCG, was identified as being highly expressed in GSCs compared to non-neoplastic neural stem cells. The GIHCG gene, located on human chromosome 12q14.1, is frequently amplified in glioblastoma and impacts overall survival. Bioinformatic and functional analyses revealed that GIHCG is amplified in 13% of GBM patient samples, and high expression of GIHCG is a negative prognostic marker for GBM patients, with significantly reduced overall survival compared to the low expression group. In addition, the depletion of GIHCG significantly reduced GSC proliferation and migration. Further, the knockdown of GIHCG decreased both mRNA and protein expression levels of critical GSC stemness factors, including SOX2, NESTIN, and OLIG2. Moreover, GIHCG depletion reduced the sphere formation capacity of GSCs, demonstrating the functional importance of GIHCG in the maintenance of GSC stemness. These results indicate that GIHCG is essential for GSC proliferation, migration, and stemness, underscoring its potential therapeutic value in RNA-based therapies for combating glioblastoma malignancy.
CSIG-12. YAP1-TEAD SIGNALING CONTRIBUTES TO LUNG CANCER COLONIZATION OF THE BRAIN
Authors: Torrini Consuelo , Nayyar Naema , Summers Elizabeth , Sasisekharan Varun , Wakimoto Hiroaki , Brastianos Priscilla
Published: November 2024

BACKGROUND

Lung cancer is the most common primary tumor to metastasize to the brain. Poor understanding of the brain metastasis process limits therapeutic options. Despite emerging data on the role of YAP signaling pathway in the development of brain tumors, a gap in knowledge remains regarding its role in brain colonization. We hypothesize that YAP1 and the associated TEAD transcriptional factors are responsible for lung cancer progression and that intervention with YAP/TEAD-targeted therapy will prevent brain dissemination.

METHODS

Lung cancer cells at different stages of cancer progression (VMRC-LCD and NCI-H1975, lung cancer cell lines; NCI-H1915 and LN001, brain metastatic cancer cells) were genetically engineered to overexpress or silence/knockout YAP1 using lentiviral transduction of constructs expressing shRNA/sgRNA or YAP1. We tested several tumor cell capabilities using well-established in vitro assays, including invasion and migration assays, and an in vivo brain metastasis (BM) model to determine the biological effects of YAP1/TEAD suppression at different stages of lung cancer progression. Dose-response assays were performed to determine IC50 of the TEAD inhibitor, verteporfin.

RESULTS

YAP overexpression enhances the proliferative phenotype in metastatic and BM cell lines but not in non-metastatic cells. However, YAP overexpression only increases the migration ability of BM cell lines such as LN001 and NCI-H1915 compared to the metastatic NCI-H1975 and non-metastatic lung cancer cells. Moreover, we showed the efficacy of the YAP1/TEAD inhibitor in patient-derived lung BM cells. Finally, our in vivo preliminary data showed YAP1 involvement in lung cancer cell colonization of the brain but not in sustaining brain metastasis growth.

CONCLUSIONS

Our findings showed YAP1 involvement in lung cancer cell colonization of the brain, suggesting YAP1 inhibition is a clinically actionable target for preventing lung cancer dissemination and providing a strong rationale to further evaluate the benefit of a YAP1/TEAD-targeted therapy in in vivo models of BM.
CSIG-16. A CX43-WNK1-C-MYC SIGNALING AXIS DRIVES GLIOBLASTOMA CANCER STEM CELL SURVIVAL
Authors: Mulkearns-Hubert Erin , Hajdari Nicole , Hong Ellen , Silver Daniel , Lathia Justin
Published: November 2024

Tumors represent a highly dynamic system that relies on coordinated signaling to drive growth and adapt to selective pressures, including those induced by anti-cancer therapies. Given the need for tumors to engage in rapid and coordinated cell-cell communication, mechanisms such as gap junction intracellular communication (GJIC) should be essential. However, the connexin proteins that make up gap junctions have traditionally been considered tumor suppressors based on the frequent loss of GJIC and lower connexin expression in tumor cells compared to non-neoplastic tissue. For this reason, connexin 43 (Cx43) has been proposed to suppress the growth of glioblastoma (GBM), the most common primary malignant brain tumor. However, recent data suggest that this tumor-suppressive effect is context dependent and that connexins can also function in a tumor-promoting role. Using next-generation sequencing techniques, we found Cx43 expressed at high levels in a panel of GBM patient-derived xenograft (PDX) CSCs and that these models rely on Cx43 for their survival and self-renewal. Mechanistically, depletion of Cx43 led to a dramatic loss of c-MYC expression through reduced phosphorylation of its upstream mediator WNK lysine-deficient protein kinase 1 (WNK1). Depletion of WNK1 phenocopied knockdown of Cx43 and reduced MYC protein and mRNA as well as tumor growth in vivo. Together, this work defines a novel signaling axis downstream of gap junction protein expression that promotes tumor growth and cancer stem cell phenotypes in GBM. Due to the difficulty in targeting both Cx43 and MYC, the identification of intermediate targetable signaling nodes may lead to improved therapies for patients with GBM.
CSIG-17. ADHESION GPCR BAI1/ADGRB1 CAN BLOCK IGF1R-MEDIATED GROWTH SIGNALLING, INCREASE RADIOSENSITIVITY AND AUGMENT SURVIVAL IN MEDULLOBLASTOMA
Authors: Yamamoto Takahiro , De Farias Virginea Araujo , Kuranaga Yuki , Zhu Dan , Parag Rashed R , Osuka Satoru , Van Meir Erwin G
Published: November 2024

Medulloblastoma (MB) is an aggressive pediatric brain tumors and increased knowledge about the disease mechanisms is needed to develop new therapeutic approaches. Brain-specific Angiogenesis Inhibitor 1 (BAI1/ADGRB1) is an adhesion GPCR receptor and tumor suppressor epigenetically silenced in MB. Our prior studies showed that BAI1 can bind the MDM2 E3 ubiquitin ligase and relocate it to the cell membrane, thereby preventing it from degrading p53 in the nucleus (Zhu et al, Cancer Cell, 2018). Whether other MDM2 targets are affected by this relocation that may be functionally important in MB development is unknown. We hypothesized that BAI1-mediated relocation of MDM2 might destabilize cell surface oncogenic receptors and found that BAI1 stimulates IGF1R poly-ubiquitination and degradation. Mechanistically, BAI1 fosters MDM2-IGF1R interaction through beta-arrestins, adaptor proteins connecting MDM2 to IGF1R. Epigenetic reactivation of BAI1 expression suppressed Stat3 and Akt signaling, and radio-sensitized MB cells, leading to significantly improved survival in orthotopic MB xenograft models in mice regardless of tumor p53 mutation status. These findings are important as they demonstrate that BAI1 has dual anti-tumor effects in MB through MDM2 membrane re-localization, stabilizing p53 and blocking IGF1R signaling. They further suggest that epigenetic targeting of BAI1 is a promising therapeutic approach for clinical translation.
CSIG-25. MAPK/ERK SIGNALING IN GLIOMAS MODULATES INTERFERON RESPONSES, PROMOTES TUMOR-MICROGLIA CROSSTALK, AND CONFERS SUSCEPTIBILITY TO ANTI-PD-1 AND ANTI-CTLA-4 IMMUNOTHERAPY
Authors: Kim Kwang-Soo , Zhang Junyi , Dmello Crismita , Grabis Elena , Arrieta Victor , Habashy Karl , Zhao Junfei , Duffy Joseph , Gould Andrew , Chen Li , Balyasnikova Irina , Canoll Peter , Sims Peter , Rabadan Raul , Lee-Chang Catalina , Heiland Dieter Henrik , Sonabend Adam
Published: November 2024

While immune checkpoint blockade (ICB) is not effective in unselected glioblastoma (GBM) patients, we previously established that MAPK/ERK signaling is associated with overall survival following anti-PD-1 and anti-CTLA-4 treatment in recurrent GBM. However, the causal relationship between MAPK/ERK signaling and susceptibility to ICB, as well as the mechanisms underlying this association, remain to be determined. We conducted in vivo kinome-wide CRISPR/Cas9 screenings in murine gliomas to identify key regulators of susceptibility to anti-PD-1 and CD8+ T-cell response and performed survival studies to validate the most relevant hits. Additionally, paired scRNA-seq with p-ERK staining, spatial transcriptomics, and ex-vivo slice culture of BRAFV600E mutant GBM tumors treated with BRAFi/MEKi were used to determine the causal relationship between MAPK signaling, tumor cell immunogenicity, and modulation of microglia phenotype. Our CRISPR/Cas9 screening results identified the MAPK pathway, particularly the RAF-MEK-ERK pathway, as the most critical modulator of glioma susceptibility to anti-tumoral immunity across all kinases. Survival studies showed that mice bearing high p-ERK gliomas exhibited prolonged survival with anti-PD-1 treatment, which was not seen when ERK phosphorylation diminished. MAPK activation in murine gliomas led to durable anti-tumoral immunity upon implant re-challenge, with memory T cell infiltration in long-term survivors. Elevated p-ERK in glioma cells was associated with interferon responses and antigen presentation. Moreover, in BRAFV600E human GBM cells with ERK1/2 knockout and in slice cultures of human BRAFV600E GBM tissue analyzed by spatial transcriptomics, we observed modulation of interferon responses by the MAPK/ERK pathway. Notably, in slice cultures from BRAFV600E mutant GBM, BRAFi/MEKi treatment disrupted the interaction between tumor cells and tumor-associated macrophages/microglia. In conclusion, the MAPK/ERK pathway is a critical driver of GBM susceptibility to anti-tumoral immunity, modulating the interferon responses and antigen-presenting machinery in glioma cells, as well as tumor cell interaction with the microenvironment.