bluuebunny/crossref_metadata_2025 huggingface dataset:
CNSC-39. INTEGRATED CLINICAL GENETIC ANALYSIS REVEALS NEUROTRANSMITTER RECEPTOR DYSREGULATION IN MENINGIOMAS CAUSING SEIZURE
Authors: Basit Khan A , McDonald Malcolm , Harmanci Akdes , English Collin , Harmanci Arif , Klisch Tiemo , Patel Akash
Published: November 2024

Molecular correlates of seizures in meningioma remain unexplored. Previously, we identified MenG molecular grouping, wherein MenG C meningiomas recur more than MenG A or B. We therefore sought to identify molecular and clinical drivers of seizures in meningioma. We identified 144 primary supratentorial meningiomas, excluding those with pre-existing epilepsy. Whole exome sequencing assessed somatic mutation burden. Bulk RNA-sequencing identified differentially expressed genes and gene ontologies (GO). Immunohistochemistry confirmed protein levels. No differences in canonical gene mutation burden (NF2, TRAF7, AKT1, KLF4, SMO, SMARC) was found between seizure and non-seizure groups. MenG C tumors had higher seizure incidence compared to MenG A or B (p=0.03). Seizure causing meningiomas, though extra-axial, exhibited dysregulated neuronal signaling genes. GABAA receptor subunit genes GABRA3 and GABRG1 were downregulated in tumors causing seizure (Log2FC=-1.67, padj=0.014; Log2FC=-2.24, padj=0.009). Immunohistochemistry confirmed expression of GABRB2 subunit, the first documentation of GABA receptor expression in meningiomas. Neuropeptide Y Receptor Y1 (NPY1R) is downregulated in seizure causing meningiomas (Log2FC=-1.64, padj=0.002). NPY1R loss correlates is observed in mesial temporal lobe epilepsy and post-electroconvulsive shock mouse brains. In GO analysis, the terms “GABA signaling pathway,” “neuropeptide signaling,” “excitatory postsynaptic membrane potential,” and “ionotropic glutamate pathway,” were downregulated in meningiomas with seizure (padj<0.05). We assessed which alterations within MenG C tumors caused seizures by identifying genes associated with both seizure presentation and MenG C classification. Glutamate ionotropic receptor AMPA type subunit 1 (GRIA1) is downregulated in MenG C tumors (Log2FC=-2.29, padj=6.02E-07) and seizure causing tumors (Log2FC=-1.75, padj=0.03). Clinically, patients experiencing pre-operative seizures more frequently had cerebral edema, non-homogenous enhancement, intratumoral calcification, higher MIB-1, atypical grade 1, reduced GCS, and ER presentation; they were less likely to have incidental or headache presentation (p<0.05 for all). MenG classification predicts seizure presentation whereas somatic mutation status does not. Meningiomas causing seizures show pathologic neurotransmitter receptor dysregulation.
CNSC-42. PROGNOSTIC VALUE OF INTERLEUKIN-6 IN PATIENTS WITH GLIOBLASTOMA
Authors: Kim Kyung Hwan
Published: November 2024

Interleukin-6 (IL-6), a pro-inflammatory cytokine, has been implicated in the invasiveness and progression of glioma. However, the association between serum IL-6 levels at specific time points during treatment and patient prognosis remains unclear. This study was aimed to investigate the prognostic value of IL-6 measured at milestones in the treatment of patients with glioblastoma. Between January 2021 and December 2022, consecutive patients with newly diagnosed glioblastoma were enrolled. Serum IL-6 concentrations were measured at different time points, including preoperative, pre- and post-radiation period, and two-month intervals thereafter. Patients with incomplete data were excluded, and increase of IL-6 values due to the overlapping with systemic infection were also excluded from the analysis. During the study period, 26 patients and 270 IL-6 levels at different time points were evaluated. The median follow-up time was 11 months. Tumor progression was evident in 19 patients (73.1%) and 13 patients (50%) were expired. Preoperative and pre-radiation IL-6 values were available in 20 and 23 patients with the median 5.25 and 4.5 pg/mL, respectively. With the cut-off value of pre-radiation IL-6 at 4.5 pg/mL, high IL-6 group showed significantly worse progression-free survival and overall survival than low IL-6 group (p = 0.027 and 0.008, respectively). However, IL-6 levels at other milestone were not related to the patient prognosis. Serum IL-6 elevation in pre-radiation period is an unfavorable prognostic factor in tumor progression and patient survival. Further research is necessary to validate the prognostic role of IL-6 and explore the underlying mechanisms.
CNSC-45. EXTRINSIC ELECTRICAL MODULATION IMPACTS GLIOBLASTOMA TUMOR GROWTH BY DISRUPTING ITS INTERCELLULAR COMMUNICATION
Authors: Aliana Irina Palacin , Eshac Yasmina , Perez Alicia Casanova , Cerda Elian Saiz , Tripathi Shashwat , Najem Hinda , Heimberger Amy , Lesniak Maciej , Sita Timothy
Published: November 2024

Glioblastoma (GBM) is an incurable primary malignant neoplasm of the central nervous system. GBM as an electrically active neoplasm diffusely colonizes healthy brain tissues, disrupting the neurotransmission balance and causing glioma-related epilepsy (GRE) in up to 50% of patients. Interestingly, GRE is an independent favorable prognostic factor for survival in GBM. The therapeutic induction of seizure may have a previously unexplored oncologic value in GBM. We have previously reported in CT-2A-bearing mice subjected to daily extrinsic electrical modulation (EEM) diminished tumor progression and increased overall survival relative to sham-treated mice, but the mechanism by which EEM produces its anti-tumor effect remains uncertain. Therefore, GBM-bearing mice (CT-2A cells xenografted into 5-7 weeks old C57BL/6 female mice, n=5/group) received either a single EEM of 2.0 millicoulombs (mC) or sham treatment. The mice were terminated at 3 hours, 24 hours, 4, 7, and 10 days post-EEM, and tumors and contralateral brain cortex were analyzed using bulk RNA-sequencing and Sequential immunofluorescence (SeqIFTM). SeqIFTM revealed how EEM activates neuronal activity via cFOS expression and induces tumor-specific cell damage through cleaved caspase-3 expression, without affecting healthy brain tissue. Furthermore, RNA-seq performed post-EEM revealed gene expression changes of not only synapse organization markers but also of several tumor-tumor and tumor-neuron connectivity key markers, such as growth-associated protein 43 (GAP43), neuroligin-3 (NLGN3), and glutamate receptors such as GRIA4 and GRIN1 between others. However, the expression of these markers diminished significantly 96h after-EEM, indicating a reduction in intercellular electrical communication by the inhibition of the neoplasm cells electrical integration with neuronal circuits by downregulating glutamatergic receptor expression, blocking the synapse-forming protein NLGN3, and the network-connecting protein GAP43. Taken together, our findings reveal how by the disruption of these critical interactions within the tumor microenvironment though EEM impacts on GBM growth making it more susceptible to therapeutic interventions.
CNSC-48. DIFFERENTIAL GENE EXPRESSION UNDERLYING EPILEPTOGENICITY IN PATIENTS WITH GLIOMAS
Authors: Mortazavi Armin , Khan Anas , Nieblas-Bedolla Edwin , Boddeti Ujwal , Bachani Muzna , Ksendzovsky Alexander , Johnson Kory , Zaghloul Kareem
Published: November 2024

BACKGROUND

Seizures are a common sequela for patients suffering from gliomas. Molecular properties are known to influence the initiation of seizures that may influence tumor growth. Different levels of gene expression associated with seizures related to gliomas remain unclear. We analyzed RNA sequencing of gliomas to further probe these differences.

METHODS

Total RNA sequencing was obtained from The Cancer Genome Atlas - Lower Grade Glioma project, comprised of 2021 WHO classification low grade gliomas, including IDH-mutant and IDH-wild type, to distinguish differential expression in patients who did and did not experience seizures. Utilizing QIAGEN Ingenuity Pathways Analysis, we identified canonical and functional pathways to further characterize differential expression.

RESULTS

Of 289 patients with gliomas, 83 (28.7%) had available information regarding seizure occurrence prior to intervention and other pertinent variables of interest. Of these, 50 (60.2%) were allocated to the seizure group. When comparing the level of RNA expression from these tumors between the seizure and non-seizure groups, 52 genes that were significantly differentially regulated were identified. We found canonical pathways that were altered, most significantly RhoGDI and Semaphorin Neuronal Repulsive signaling. Functional gene analysis revealed tumors that promoted seizures had significantly increased functional gene sets involving neuronal differentiation and synaptogenesis.

CONCLUSIONS

In the setting of gliomas, differences in tumor gene expression exist between individuals with and without seizures, despite similarities in patient demographics and other tumor characteristics. There are significant differences in gene expression associated with neuron development and synaptogenesis, ultimately suggesting a mechanistic role of a tumor-neuron synapse in seizure initiation.
CNSC-50. PRIMARY INTRACRANIAL CONGENITAL GLIOBLASTOMA (PICG): A SYSTEMATIC REVIEW OF CASE REPORTS FROM 2000 TO 2023
Authors: Qadri Haseeb Mehmood , Bashir Asif
Published: November 2024

BACKGROUND AND OBJECTIVE

The most commonly reported congenital intracranial space occupying lesions are teratoma, glioma and neuroblastoma. Primary intracranial congenital glioblastoma (PICG) is one of the most lethal and extremely rare neoplasms. Most pediatricians and gynecologists are unable to detect it congenitally, posing an ominous risk of spread and disease severity. We aim to determine the clinical manifestations, number of reported cases, radiological findings and neuro-oncological management of PICG.

MATERIALS AND METHODS

A comprehensive literature search using PubMed Central and Google Scholar was done, retrieving 17 case reports and five case series of 31 patients with PICG and included using the Preferred Reporting items for Systematic Reviews and Meta-Analyses guidelines, published between 2000 and 2023.

RESULTS

The mean age at presentation was 86.00 ± 88.36 days, with both genders affected equally, i.e. 45.16%. The most common symptoms and signs at presentation were seizures (38.70%) and hydrocephalus (51.61%), respectively. Left hemispheric (48.38%), with frontoparietal involvement (16.12%) was the frequently affected site. MRI findings were suggestive of low intensity signal significant of hemorrhage or calcification and a heterogenous mass in 35.58% and 32.25% cases, respectively. Gross total resection (GTR) was achievable in 48.38% patients. Glial fibrillary acid protein and vimentin were positive in 45.16% and 29.03% cases, respectively. Intraoperative mortality and recurrence were noted in 25.80% and 9.68% of patients, respectively. The average follow up duration was 20.57 months.

CONCLUSION

PICG has an extremely aggressive course of natural progression. Congenital presentation and its lack of awareness among clinicians is itself a challenge for disease management. Adjuvant chemo-radiotherapy has proven fruitful along with GTR. Post-operative CSF diversion is warranted.
CNSC-53. SHH ACTIVATION IN DEDIFFERENTIATION DURING TUMOR PROGRESSION IN MPNST
Authors: Yakubov Rebeca , Bunda Severa , Zadeh Gelareh
Published: November 2024

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are highly aggressive sarcomas with little progress on outcomes and treatment strategies. Previously, unsupervised analyses of methylome and transcriptome profiles of 108 peripheral nerve sheath tumors uncovered two subgroups of MPNSTs that predict progression-free survival, MPNST-G1 (characterized by SHH-pathway activation) and MPNST-G2 (characterized by WNT/ß-catenin/CCND1-pathway activation). Further, single nuclear RNA sequencing revealed that MPNST-G1 and MPNST-G2 cells resemble neural crest-like and Schwann cell precursor-like cells, respectively.

PURPOSE & HYPOTHESIS

To examine whether the activation of the SHH pathway in MPNST-G1 cell lines induces overexpression of factors known to play canonical roles in early neural crest cell specification (TWIST1, SNAI2, PAX3, PAX6, SOX9, OTX2) and to investigate the role of Src activation on SHH pathway-induced dedifferentiation. We hypothesize that MPNST-G1 cells will exhibit SHH pathway activation, synergizing with Src to induce the overexpression of early neural crest cell (ENCC) transcription factors.

METHODS

SHH pathway activation, expression of ENCC transcription factors, and effects of inhibitors were analyzed in MPNST-G1 cells using RT-PCR, western blotting, Alamar Blue assay, Trypan Blue assay, and Soft Agar Transformation assay.

RESULTS

Compared to MPNST-G2 cells, MPNST-G1 cells displayed SHH-pathway activation, SMO-dependent activation of Src, and elevated expression of the ENCC transcription factors. Sonidegib (SMO inhibitor) and Dasatinib (Src inhibitor) were able to revert dedifferentiation.

CONCLUSIONS

The SHH-pathway cooperates with Src to promote expression of important transcription factors in dedifferentiation. This finding provides insights into the transformation process of MPNST and novel therapeutic options.
CNSC-54. CENTRAL AND BOUNDARY-DRIVEN GROWTH PATTERNS DOMINATE RESPECTIVELY IDH WILD-TYPE AND MUTANT GLIOMAS
Authors: Kyriakidou Maria , Urbaniak Konnie , Mbegbu Mimi , Rockne Russell , Wesseling Pieter , Eijgelaar Roelant , Anderson Kevin J , Verhaak Roel , de Witt-Hamer Phillip , Verburg Niels , Branciamore Sergio , Barthel Floris P
Published: November 2024

Diffuse gliomas are the most prevalent primary malignant brain tumors in adults and are characterized by invasive growth and poor prognosis. Tumor cells infiltrate the brain parenchyma and spread to distant sites. The aim of this study is to characterize the spatial heterogeneity, mode, and direction of tumor development to identify key areas for localized treatment. Neuronavigation was employed to collect n=134 image-guided samples from n=16 adult patients with diffuse gliomas, including n=7 IDH wild-type (IDHwt) and n=9 IDH mutant (IDHmut) tumors from regions with and without MRI abnormalities. Collected samples were subjected to targeted and shallow whole-genome sequencing. Somatic variants were used to determine the evolutionary processes governing heterogeneity. Examination of the dN/dS ratio, Tajima’s D score, and MOBSTER model suggested that all tumors are consistent with neutral evolution, as previously reported. Considering that genetic heterogeneity was a result of stochastic mutations, we used phylogeographic relationships between samples to dissect the spatiotemporal development of these tumors. Evolutionary (patristic) and cartesian (Euclidean) distances between sample pairs from the same patient were correlated in n=2/9 IDHmut and n=2/7 IDHwt patients, suggesting that migratory or punctuated evolutionary processes play a major role in tumor diffusion. An examination of spatial diffusion revealed that the latest descendant appeared peripherally in n=5/9 IDHmut patients, suggesting boundary-driven growth. In the remaining cases, three patients exhibited centrally-driven growth, whereas a fourth patient displayed a mixed pattern. In contrast, in n=4/7 IDHwt patients, descendants appeared closer to the tumor center, suggesting centrally-driven growth. In the remaining three IDHwt patients, one patient showed a diffusion that was consistent with boundary-driven growth, while the other two patients showed a mixed pattern. Taken together our data suggest that IDHwt tumors tend to develop centrally, whereas IDHmut tumors preferably develop outward. Our data could aid in tailoring localized treatment based on projected growth patterns.
CNSC-56. DIVERSE, FUNCTIONAL NEUROTRANSMITTER RECEPTOR EXPRESSION ON GLIOBLASTOMA CELLS ENABLES EXTENSIVE NEURON-TO-GLIOMA COMMUNICATION
Authors: Wagner Julia , Tetzlaff Svenja , Reyhan Ekin , Venkataramani Varun
Published: November 2024

Glioblastomas are invasive yet incurable brain tumors. Recent data have shown that glutamatergic neuron-to-glioma synapses drive glioblastoma proliferation and invasion. In this study, we set out to investigate whether glioblastoma could communicate with neurons via various neuron-derived neurotransmitters through a functional neurotransmitter receptor screening. For this purpose, we stably transduced glioblastoma cells with a genetically encoded calcium indicator and sequentially and locally applied eight different neurotransmitters to glioblastoma cells in neuron-glioma co-cultures. These neurotransmitters included acetylcholine, ATP, dopamine, glutamate, GABA, adrenaline, serotonin, and glycine. We observed functional responses to acetylcholine, glutamate, ATP, dopamine, indicating a potential role for diverse neuron-to-glioma communication. Further, we investigated in patient-derived xenograft models and human tissues the existence of putative neuron-to-glioma synapses that could signal via acetlycholine, ATP and dopamine. In conclusion, this study reveals that glioblastoma cells express a heterogeneous set of functional neurotransmitter receptors, which may facilitate neuron-to-tumor communication across broad neuronal populations and warrant further investigation into their role for tumor biology.
CNSC-66. STRUCTURAL AND ELECTROPHYSIOLOGICAL CONNECTIVITY IN GLIOBLASTOMA IS MEDIATED BY TUMOR AND IMMUNE DERIVED CYTOKINES
Authors: Picart Thiebaud , Krishna Saritha , Daniel Andy , Dada Abraham , Oten Sena , Jeanette Hyer , Hervey-Jumper Shawn
Published: November 2024

BACKGROUND

In glioblastomas (GBM), the pleiotropic cytokine interleukin-6 (IL-6) upregulates PD-L1 expression. This results in local immunosuppression favorable to tumor progression, and may account for the limited efficacy of immune checkpoint inhibition. Additionally, IL-6 increases synaptogenesis during development, and contributes to neuronal network remodeling following focal brain or spinal cord injury. Therefore, the aim was to determine whether IL-6 contributes to GBM-induced circuit remodeling from a structural and electrophysiological perspective.

METHODS

In magnetoencephalography (MEG)-based intratumoral regions of High- (HFC) and Low-Functional Connectivity (LFC) from GBM patients, the expression of IL-6 and GAP43 was compared using bulk and single-cell RNA sequencing and immunofluorescence staining in biological replicates (n=44). In mouse postnatal cortical neurons and primary patient-derived GBM cell cocultures, the expression of Ki67, GAP43, tumor connectivity and neuronal activity were monitored after exogenous application of recombinant human IL-6 (rIL-6) or microglial depletion using PLX5622. Results. IL-6 and GAP43 were overexpressed in HFC compared to LFC regions. In neuron-GBM cocultures, the tumour proliferation index was significantly increased by rIL-6 and decreased by PLX5622. Morphologically, the number of microtubes per tumor cell was significantly increased by rIL-6 and decreased by PLX5622. The expression of GAP43 was inconstantly increased by rIL-6, suggesting the regulation of other pathways involved in tumour microtube formation. Multielectrode array recordings showed a significant increase or decrease in the neuronal activity, following the addition of rIL-6 or microglial depletion, respectively.

CONCLUSIONS

IL-6-signaling increases proliferation, structural and electrophysiological connectivity in gliomas and may contribute to neuronal network hyper-excitability and synchrony. Microglial depletion provided opposite effects. Additional experiments are mandatory to determine whether the effects of IL-6 on GBM cells depend on the presence of microglial cells or not. These data will be critical to design new therapeutic options, likely to improve the oncological and functional outcomes of patients treated for GBM.
CNSC-69. GLIOBLASTOMA-NETWORK CONNECTIVITY IS REGULATED THROUGH ALTERATIONS IN CHLORIDE HOMEOSTASIS AND GABAERGIC SIGNALING
Authors: Krishna Saritha , Gonzales Cesar Nava , Daniel Andy , Lee Kevin , Dada Abraham , Yamada Hunter , Ambati Vardhaan , Viswanath Pavithra , Hervey-Jumper Shawn
Published: November 2024

The specific pathophysiological mechanisms underlying glioma-related epilepsy, which presents an unfavorable clinical course, are still not well explored. To identify the candidate pathways involved in glioblastoma-induced neuronal hyperexcitability, we used high-density electrode arrays in vivo in humans to record local field potentials from cortically projecting gliomas and identified hyperexcitable intratumoral regions with elevated functional connectivity to the brain. Single-cell RNA sequencing (13,730 cells analyzed) of the functionally connected intratumoral regions identified several circuit assembly and GABAergic signaling genes elevated in glioma-intrinsic neurons, including the sodium-potassium-chloride co-transporter 1 (NKCC1), which accumulates chloride in the cells. We hypothesized that the hyperexcitable behavior of glioma-intrinsic neurons in glioblastoma is mediated by elevated NKCC1 and chloride dysregulation and that inhibiting NKCC1 would reinforce the inhibitory action of GABA and rescue the neuronal hyperresponsive phenotype. Single-nucleus (sNuc-seq) sequencing was performed on neuron-glioblastoma co-cultures (54,000 cells analyzed) to determine NKCC1-facilitated GABAergic signaling in glioblastoma-mediated neuronal responses. Mechanistic and functional studies using perforated whole-cell patch-clamp recordings, multielectrode array, calcium, and chloride imaging for validating therapeutic vulnerabilities to NKCC1 silencing by shRNA knockdown and by the FDA-approved drug bumetanide were performed using in vitro and organotypic mouse slice culture models. sNuc-seq revealed an upregulation of neuronal NKCC1 and GABAA receptors when co-cultured with NKCC1-high-expressing glioblastoma cells, indicating the strong association between neuronal NKCC1 and GABAergic signaling. Electrophysiological analysis of glioblastoma-neuron co-cultures demonstrated increased network burst synchrony and a positive shift in the GABA reversal potential (EGABA). This increase was eliminated in the presence of NKCC1 inhibition using bumetanide and shRNA knockdown, which correlated with a significant decrease in intracellular neuronal chloride. Mechanistically, glioma NKCC1 downregulation significantly decreased GAP43-mediated tumor microtube (TMT) formation. Whether this reduced TMT formation also results in decreased chloride release by glioma cells, thereby altering neuronal chloride equilibrium, is currently under investigation. Collectively, these findings aim to identify a new mechanism of glioma-associated epilepsy, which may provide a novel approach to treatment.
STEM-07. UNVEILING THE ROLE OF HYPOXIA AND TAM-SECRETED TGF-Β1 IN PROMOTING GLIOMA STEM CELL MAINTENANCE VIA YAP/TAZ ACTIVATION IN GLIOBLASTOMA PERI-NECROTIC NICHE
Authors: Shih Ling-Kai , Gruchala Tomasz , Li Jiabo , Lam Nicholas , Brat Daniel
Published: November 2024

Glioblastoma (GBM) is a highly malignant brain tumor with rapid growth and poor outcomes. In the tumor microenvironment (TME), necrosis triggers significant reshaping and rapid progression, marked by tumor-associated macrophages (TAMs) and glioma stem cells (GSCs) accumulation in peri-necrotic zones. Analysis of Ivy-GAP and single-cell RNA-Seq data revealed consistent Hippo pathway activation in the hypoxic peri-necrotic zone, despite canonical stem-cell transcription factors such as SOX2, OLIG2, and FOXM1 not being upregulated. We hypothesize that Hippo transcription activation may promote GSC stemness via direct effects of hypoxia and/or TAM-secreted cytokines. Exposing patient-derived GBM neurospheres to 1% hypoxia increased nuclear YAP1 and TAZ expression, along with CYR61, a Hippo pathway readout, compared to normoxia at 48 hours. Single-cell RNA-Seq identified potential hypoxia-regulated genes upstream of YAP/TAZ, including Zyxin, upregulated in 1% hypoxia-treated cultures, possibly facilitating nuclear YAP/TAZ transport. Culturing GBM cells with primary macrophage-conditioned media activated Hippo transcription, with TGF-β1 identified as a hypoxia-specific driver of malignant cell gene expression with single-cell RNA-Seq analysis using NichenetR. Treating GBM cells with TGF-β1 increased CYR61 expression, signifying Hippo transcription activation. Furthermore, we showed that hypoxia and TGF-β1 synergistically maintained GSCs with extreme limiting dilution assays. In the immunocompetent RCAS/tv-a mouse model, Verteporfin, a YAP/TAZ inhibitor, significantly reduced tumor size and prolonged mouse lifespan. TAZ knockdown similarly extended lifespan and reduced tumor growth, with flow cytometry showing a decrease in CD133/CD44 positive GSC populations in knockdown mice. These findings suggest the conclusion that hypoxia and TAM-secreted TGF-β1 directly stimulate YAP/TAZ activation and potentially promote GSC stemness in the GBM peri-necrotic niche.
STEM-11. MULTIDIMENSIONAL PROFILING OF TUMOR CELL HETEROGENEITY REVEALS CELL-LINEAGE SPECIFIC FUNCTIONS IN SUPRATENTORIAL EPENDYMOMAS
Authors: Jeong Daeun , Danielli Sara G , Maaß Kendra , Ghasemi David R , Tetzlaff Svenja K , Reyhan Ekin , de Biagi-Junior Carlos Alberto Oliveira , Cascio Costanza Lo , Neyazi Sina , Nascimento Andrezza , Haase Rebecca , Englinger Bernhard , Jiang Li , Nguyen Cuong M , Baumgartner Alicia-Christina , Castellani Sophia , Rozowsky Jacob S , Hack Olivia A , Shaw McKenzie L , Lotsch-Gojo Daniela , Bruckner Katharina , Pfister Stefan M , Kool Marcel , Nowakowski Tomasz , Gojo Johannes , Baird Lissa , Alexandrescu Sanda , Pajtler Kristian W , Venkataramani Varun , Filbin Mariella G
Published: November 2024

Supratentorial ependymomas (ST-EPN) are aggressive pediatric brain tumors that are categorized into distinct molecular subgroups. However, the developmental origins, tumor microenvironment, and phenotypic characteristics of tumor subpopulations across these subgroups are still poorly understood. In this study, we explored the human developmental signatures, global spatial organization, and the morphological and migratory tumor cell state behaviors in ST-EPN tumors at unprecedented resolution. We profiled 42 ST-EPN patients encompassing ZFTA-RELA (n = 20), ZFTA-Clusters 1 to 4 (n=20), and ST-YAP1 (n=4) subgroups by single-cell RNA sequencing (scRNA-seq), spatial transcriptomics, and live-cell imaging. We identified recurrent tumor cell states across tumors, that cover both generic cell processes (including cycling and mesenchymal/hypoxia) and human embryonic and fetal brain developmental signatures. ST-EPN subgroups displayed distinct developmental signatures, mapping to two separate temporally restricted progenitors-neuroepithelial-like and embryonic-like cells. Additionally, tumors showed diverging patterns of neuronal or ependymal differentiation, with ZFTA-Cluster 3 tumors as especially distinct from other subgroups in both developmental origin and differentiation. Furthermore, by utilizing 10X Xenium and novel algorithms we discovered that mesenchymal/hypoxia is critical for driving global tissue architecture to become more organized. Notably, recurrent tumors exhibited higher proportion of mesenchymal/hypoxia cells and greater structure than primary tumors. Lastly, by superimposing molecular and functional assays in both in vivo and in vitro models, we found that cell states exhibit distinct morphological and migratory behaviors, with neuronal-like cells being the most invasive. Neuronal-like cells especially exhibited distinct behavioral patterns reminiscent of neuronal migration during development. Moreover, we demonstrated the crucial role of neuronal microenvironment in promoting plasticity of cells toward this neuronal lineage. Taken together, we present a multidimensional framework for investigating cellular states within ST-EPN tumors, offering novel insights into their developmental origins, patterns of spatial organization, and cellular behavioral characteristics.
STEM-13. NUCLEAR LOCALIZATION OF ALPHA-1-ANTICHYMOTRYPSIN INCREASES IN GLIOBLASTOMA FOLLOWING STANDARD OF CARE TREATMENT
Authors: González Aura Figueroa , Carrano Anna , Norton Emily S , Russo Marissa , Quiñones-Hinojosa Alfredo , Guerrero-Cázares Hugo
Published: November 2024

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults with a median survival of 8-14 months and 5-year survival rate of 6.9%. Its aggressive nature arises mostly from molecular heterogeneity and resistance to standard of care (SOC), including radiation and temozolomide (TMZ). Recurrence is nearly inevitable, driven by highly invasive brain tumor initiating cells (BTICs). Our previous studies revealed that exposing BTICs to cerebrospinal fluid (CSF) from GBM patients increases cell migration and proliferation compared to non-cancer CSF. Transcriptomic analysis identified the upregulation of the SERPINA3 gene, which encodes alpha-1-antichymotrypsin (ACT). Silencing of SERPINA3 reduces BTIC migration and proliferation and abolishes the promigratory response to GBM-derived CSF, highlighting SERPINA3 as a potential therapeutic target. ACT has been reported to bind to DNA, although the implications of this interaction are unknown. We have previously observed higher levels of intranuclear ACT in human GBM compared to non-cancer brain tissues. We hypothesize that the nuclear localization of SERPINA3 in GBM contributes to increased malignancy, opening the possibility of therapeutically targeting its intranuclear transport. Here, we determined the intracellular localization of ACT in BTICs and GBM and compared it to non-cancer tissues. Additionally, we evaluated whether SOC affected intranuclear localization of ACT. Patient-derived BTICs were treated with TMZ, radiation, and a combination of both, to assess changes in ACT expression via Western Blot, PCR, and ICC. A decrease in cell confluency was correlated with a significant decrease (p<0.05) in SERPINA3 mRNA and overall protein expression when BTICs were treated with TMZ alone or in combination. Interestingly, confocal microscopy revealed a significant increase (p<0.05) in its nuclear localization, particularly with TMZ treatment, indicating a change in its intracellular distribution. Overall, nuclear translocation of SERPINA3 increases in response to SOC with potential implications as a treatment resistance mechanism.
STEM-14. INTEGRATED ANALYSIS OF GLIOBLASTOMA PROGENITOR SUBTYPES REVEALS A TUMOR-DERIVED STEM CELL POPULATION WITH NEURAL AND VASCULAR POTENTIAL
Authors: Fazzari Elisa , Azizad Daria , Li Matthew , Yu Kwanha , Ge Weihong , Nano Patricia , Kan Ryan , Soto Jose , Crouch Elizabeth , Raleigh David , Cadet Dimitri , Tse Christopher , Tum Andrew , Bayley Nicholas , Deneen Benjamin , Patel Kunal , Nathanson David , Bhaduri Aparna
Published: November 2024

Glioblastoma (GBM) exhibits a vast heterogeneity in cell types and states. Recent research highlights the reactivation of neurodevelopmental programs in GBM, contributing to this heterogeneity and, ultimately, therapy resistance. To characterize the landscape of progenitor cell types in human primary GBM, we compiled a meta-atlas of single-cell transcriptomes from seven published studies. Using a novel bioinformatic method for gene program analysis, we derived GBM gene expression meta-modules represented across multiple tumors. Our analyses validated previously described GBM gene programs and revealed novel tumor progenitor subtypes. Among these subtypes, we identified a tumor-derived stem cell population exhibiting a mixed vascular identity and transcriptional programs reminiscent of neural stem cells, which we identified as a putative neurovascular progenitor (NVP). To our knowledge, this population has not been previously described in GBM. We validated the existence of NVPs in situ using immunofluorescence from primary patient GBM samples. We then performed an enrichment for NVPs using fluorescence-activated cell sorting direct from patient tumors, followed by single-cell RNA sequencing. Examination of data from traditional model systems, including gliomaspheres and mouse GBM models, confirmed the preservation of NVP identity across systems. In vivo analysis of NVPs in multiple mouse models of GBM elucidate the influence of NVPs on GBM cell type composition, highlighting their role as multipotent progenitors. Finally, we utilized single-cell lineage barcoding to trace the progeny of patient-derived NVP cells in a novel organoid transplantation model, revealing NVP differentiation into vascular-like and neural-like cells. These data indicate that NVP cells play crucial roles in tumor plasticity and may represent a valuable therapeutic target for future exploration.
STEM-15. THE IMPACT OF TUMOR TREATING FIELDS (TTFIELDS) ON CANCER STEM-LIKE CELLS ISOLATED FROM THE SUB-VENTRICULAR ZONE OF GLIOBLASTOMA PATIENTS
Authors: Muñoz Yamhilette Licón , Sidebottom Rachel B , Varela Samantha , Bowers Christian A , Piccirillo Sara G M
Published: November 2024

Treatment of glioblastoma (GBM) is challenging due to its heterogeneous nature, invasive potential, and poor response to standard-of-care treatments. Areas of residual disease represent the source of the recurrent tumor that is fatal for GBM patients. However, targeting the residual disease is not offered as part of the standard of care because these areas are difficult to identify. Our laboratory was the first to identify and characterize residual disease in the sub-ventricular zone (SVZ) of the lateral ventricles of GBM patients. In this study, we are examining the impact of Tumor Treating Fields (TTFields) on treatment-resistant cancer stem-like cells (CSCs) isolated from the SVZ of 12 GBM patients using single-cell transcriptomics and functional phenotyping analysis. These cells are maintained in conditions that preserve the molecular profile of the original patient tumor, thus representing bona fide models to study the impact of TTFields on GBM residual disease. Our results show that: CSCs isolated from the SVZ from different individuals show different sensitivity to TTFields, the anti-proliferative effects of TTFields are maintained at different plating cell densities, and when the frequency of TTFields increase from 50 kHz to 200 kHz, CSCs undergo morphological changes (e.g., fewer spheres and fewer connections between cells). We used 100 μM Temozolomide and ionizing radiation (10 Gy) mimicking the standard of care of GBM patients, and the growth of the treatment-resistant CSCs was inhibited by TTFields (200 kHz). To elucidate how TTFields impact the cellular and molecular characteristics of CSCs in their microenvironment, ongoing work focuses on single-cell transcriptomics and functional phenotyping analysis. These results extend our understanding of the mechanisms of action of TTFields, specifically on how TTFields have the potential to alter the cytokine-mediated cross-talk between CSCs of the SVZ and their microenvironment.
STEM-18. A HIGH THROUGHPUT NEUROSPHERE BASED COLONY FORMATION ASSAY TO VALIDATE DRUG AND RADIATION EFFECTIVENESS IN PATIENT DERIVED XENOLINES
Authors: Kumar Manoj , Anderson Joshua , Alrefai Hasan , Nassour Lauren , Schanel Taylor , Hicks Patricia , Willey Christopher
Published: November 2024

Glioblastoma (GBM) is a primary malignant brain tumor developed from normal astrocytes. GBM patients’ median survival is less than 2 years despite safe surgical resection, fractionated conventional radiation, and temozolomide (TMZ) therapy. Few currently used drugs are successful in GBM although there are many FDA approved blood-brain barrier (BBB) penetrant drugs, for other uses that have not been screened in GBM. We utilized a panel of 734 of these BBB penetrant drugs in different GBM patient derived xenolines (PDX) along with acquired radio-resistant derivatives (-RT) including X1441, JX14P, JX14P-RT, JX39P, JX39P-RT and normal human astrocytes (NHA) as control and screened for viability with Cell Titer-Glo. We identified multiple candidate drugs that preferentially killed GBM PDX cells at 10 µM relative to NHA control. As we used stem cell media (serum free) in our drug screening study, it indicates that the potent drugs are also effective in killing cancer stem cells or brain tumor initiating cells. These drugs had targets ranging from PDGFR, DNA/RNA synthesis, as well as other kinase inhibitors. We developed a high throughput (HT), neurosphere based colony formation assay (CFA) in 96-well plate to screen multiple drugs and doses in combination with radiation. For visualizing the colonies, we use a Cytation 5 imager at 4X resolution and count the colonies based on parameters including object size, width, intensity and others. We plan on validating our drug screen and HT-CFA assay with high throughput PamChip kinase activity assays and with in vivo orthotopic tumor PDX models.
CCRG-01. MYT1 BLOCKADE AS A NOVEL GLIOMA THERAPEUTICS THROUGH ABROGATIING OF THE G2/M CELL CYCLE CHECKPOINT
Authors: Lang Fengchao , Cornwell James , Zhang Wei , Zhang Meili , Song Hua , Aladjem Mirit , Aregger Michael , Cappell Steven , Yang Chunzhang
Published: November 2024

BACKGROUND

The cell cycle is tightly regulated by checkpoints, which play a vital role in controlling its progression and timing. Cancer cells exploit the G2/M checkpoint, which serves as a resistance mechanism against genotoxic anticancer treatments, allowing for DNA repair prior to cell division. Manipulating cell cycle timing has emerged as a potential strategy to augment the effectiveness of DNA damage-based therapies.

METHODS

In this study, we conducted a forward genome-wide CRISPR/Cas9 screening with repeated exposure to the alkylating agent temozolomide (TMZ) to investigate the mechanisms underlying tumor cell survival under genotoxic stress. The screening hits were validated through in patient derived glioma cells and xenografts.

RESULTS

Our findings revealed that canonical DNA repair pathways, including the Ataxia–telangiectasia mutated (ATM)/Fanconi and mismatch repair, determine cell fate under genotoxic stress. Notably, we identified the critical role of PKMYT1, in ensuring cell survival. Depletion of PKMYT1 led to overwhelming TMZ-induced cytotoxicity in cancer cells. Isobologram analysis demonstrated potent drug synergy between alkylating agents and a Myt1 kinase inhibitor, RP-6306. Mechanistically, inhibiting Myt1 forced G2/M-arrested cells into an unscheduled transition to the mitotic phase without complete resolution of DNA damage. This forced entry into mitosis, along with persistent DNA damage, resulted in severe mitotic abnormalities. Ultimately, these aberrations led to mitotic exit with substantial apoptosis. Preclinical animal studies demonstrated that the combination regimen involving TMZ and RP-6306 prolonged the overall survival of glioma-bearing mice.
CSIG-01. DECREASING EXPRESSION OF TRAF PROTEINS WITH INCREASING MALIGNANCY WITH LOWEST EXPRESSION IN IDH-WILDTYP GLIOBLASTOMA
Authors: Timmer Marco , Kuhl Saskia , Goldbrunner Roland
Published: November 2024

The tumor necrosis factor receptor-associated factors (TRAF) are cytoplasmatic adapter proteins that can interact directly with the intracellular domains of cell surface receptors, such as the TNF receptor superfamily. TRAFs are thus involved in cellular processes like proliferation or apoptosis. Seven members are known; all expressed in the cytosol of various cell and tissue types. Increased levels of TRAF4 in GBM tissue are related to cell proliferation and migration. About 25 % of grade I meningioma show mutations in TRAF7, which are associated with a lower risk of malignant transformation. Therefore expression patterns of all seven TRAF members are evaluated in different glioma grades. Following tumor samples were obtained during neurosurgery and shock frozen in liquid nitrogen: peritumoral tissue, astrocytoma and oligodendroglioma (G2, G3) and glioblastoma (primary and recurrent). Transcription rate of TRAF1-7 was measured via qPCR. Correlation of TRAF expression level and patient overall survival was evaluated using TCGA datasets of the TCGA-LGG” and “TCGA-GBM” projects. With the exception of TRAF5, a decreased mRNA level with increasing malignancy could be found for all TRAFs (TRAF1 p=n.s.; TRAF2 p=0.0026; TRAF3 p<0.0001; TRAF4 p=0.0021; TRAF6 p<0.0001; TRAF7 p<0.0001). IDHwt glioblastoma showed significant lower expression level compared to IDHmut glioblstoma in all TRAFs except for TRAF1 (TRAF2 p<0.0001; TRAF3 p=0.0346; TRAF4 p<0.0001; TRAF6 p=0.0447; TRAF7 p=0.0081). TRAF5 again showed a reverse effect (p=0.0065). Correlation of TRAF expression level in low grade glioma and patient survival revealed longer overall survival with low TRAF1,2,4 and TRAF5 expression (p<0.0001, p= 0.0178, p=0.0307, p<0.0001). No difference in survival rate in high grade glioma could be found.
CSIG-03. MT-125 INHIBITS NON-MUSCLE MYOSIN IIA AND IIB, SYNERGIZES WITH ONCOGENIC KINASE INHIBITORS, AND PROLONGS SURVIVAL IN GLIOBLASTOMA
Authors: Rosenfeld Steven , kenchappa rajappa , Radnai Laszlo , Zarco Natanael , Dovas Athanassios , Haddock Ashley , Canoll Peter , Rumbaugh Gavin , Griffin Patrick , Kamenecka Theodore , Miller Courtney
Published: November 2024

We have shown that members of the non-muscle myosin II (NMII) family of molecular motors are non-redundant drivers of both invasion and proliferation in glioblastoma (GBM), consistent with the canonical roles NMII isoforms play in cell motility and cytokinesis. However, we have also found that NMII also has a non-canonical role by regulating oncogenic signaling pathways relevant to GBM pathogenesis. This unexpected finding has led us to identify and characterize MT-125, a highly specific small molecule inhibitor of the two predominant NMII isoforms in GBM (NMIIA and NMIIB), and we have studied its effects in pre-clinical GBM models. MT-125 has high brain penetrance and retention; an excellent safety profile in rodents and canines with no changes in metabolic or hematologic indices after prolonged administration; is well-tolerated with daily dosing for at least 85 consecutive days; blocks GBM invasion and cytokinesis, consistent with the canonical roles of NMII; and prolongs median survival by 35% as a single agent in murine GBM models. MT-125 increases signaling along both the PDGFR- and MAPK-driven pathways through a mechanism that involves the upregulation of reactive oxygen species, leading to oncogene addiction to these pathways. As a consequence, MT-125 is synthetically lethal when combined with FDA-approved, CNS-permeant inhibitors of PDGFR and mTOR in vitro. Combining MT-125 with sunitinib, a PDGFR inhibitor, or paxalisib, a combined PI3 Kinase/mTOR inhibitor, in vivo doubles median survival in a highly aggressive murine orthotopic GBM model. Furthermore, combining MT-125 with sunitinib produces tumor free remissions of >100 days--2.5-fold greater than median survival of either drug alone—in approximately 40% of mice. Our results provide a powerful rationale for developing NMII targeting strategies to treat cancer and demonstrate that MT-125 has strong clinical potential for the treatment of GBM.
CSIG-05. IS THERE ANY BRAIN TUMOR PREDISPOSITION IN RELATED PALLISTER-HALL SYNDROMES AT THE NEW GENOMICS ERA
Authors: Abdelmoula Nouha Bouayed , Kammoun Sonda , Rekik Mona , Amor Saloua Ben , Fatma Mzid Abid , Sellami Sahla , Sehli Mariem , Mrad Aymen Ben , Chaabouni Karim , Trigui Amira
Published: November 2024

Pallister-Hall Syndrome (PHS) and its related syndromes are a spectrum of congenital malformations. They are associated to GLI3 mutations and specific brain tumors. Considered as lethal, it is now well established that this disease may be miss-diagnosed with the report of adult cases. Here, we discuss the management of the genetic counselling and the risk of neurologic tumor predisposition in GLI3-related PHS. We comprehensively reviewed the scientific literature using various databases to explore the risk of neurologic tumors and evolving practice of neuro-cancer genetic counseling in GLI3-related PHS. The review of literature showed that GLI3 is involved in tissue development as well as in cancer. GLI3 was identified as either a pro or anti-cancerous protein. In fact, GLI3 is described as upregulated in multiple cancers and is found to positively regulate malignant behavior. In neuro-oncology GLI gene was first identified as a highly expressed gene in human glioma and then as having an anti-cancerous role in medulloblastoma where GLI3 seems act as a tumor suppressor. In mutational studies, GLI3-germinal mutations are characterized by a high recurrence of hypothalamic hamartoma in syndromic patients. GLI3-somatic alterations have been also demonstrated in cell samples of patients with non-syndromic hypothalamic hamartoma. In addition, while inactivation of GLI3 is suggested to be associated with medulloblastoma, mutations are not common in sporadic medulloblastoma. The association of germinal GLI3 variants in syndromic patients with medulloblastoma has been identified in only one patient harboring GLI3 H302X variant. Our review permitted us to conclude that germline GLI3 mutations may predispose to a specific non-severe form of delayed hypothalamic hamartoma, which can be revealed in pauci or asymptomatic and unrecognized mutated individuals. The likelihood of having a neuro-cancer predisposition in GLI3 mutated families seems to be insignificant.
CSIG-07. JAK1/STAT1/3 COOPERATES WITH THE CIC-FUSIONS TO DRIVE CIC-REARRANGED SARCOMAS
Authors: Kaloti Ramneet , Bunda Severa , Zadeh Gelareh
Published: November 2024

CIC-rearranged sarcoma (CRS) is an rare disease driven by a specific fusion protein involving the CIC gene. Occurrence in the brain is 3% in all CRS patients. The native CIC protein is a transcriptional repressor of the (RTK)/Ras/ERK signaling pathway, which is one of the most tumorigenic pathways in cancer. The most common rearrangement is with the double homeobox 4 (DUX4) transcription factor (CIC-DUX4), and others, such as CIC-NUTM1 fusions, have been identified in a subset of pediatric primitive neuroectodermal tumors. However, the molecular mechanisms by which CIC-fusions drive CRS remain unknown. Preliminary data shows that CIC-DUX4/NUTM1 fusions activate JAK and its downstream effector STAT1/3. We hypothesize that the JAK/STAT1/3 signal transduction pathway cooperates with CIC-fusions to induce the expression of oncogenic transcription factors ETV1/4/5 and drive these sarcomas. We show high levels of JAK1/STAT1/3 activation in patient-derived CRS cell lines (NCC-SCC-89/C) as compared to other sarcoma cell lines without the fusion. JAK1 inhibition using Solicitinib and Ruxolitinib reduced phosphorylation of STAT1/3 as well as protein and mRNA expression of ETV1/4/5, promoter activity of ETV5, cell proliferation and tumorgenicity. Interestingly DUX4 is involved in histone acetylation and STAT1 has been shown to activate p300/CBP complex which lead us to evaluating the role of STAT1 in the gene activation CRS. We elucidate mechanistically that the fusion proteins increase binding of STAT1/3 at the promoters of ETV 1/4/5. Importantly, JAK1 inhibition effectively reduces histone acetylation induced by CIC-fusions at the promoters of ETV1/4/5. To evaluate the pre-clinical effect of targeting the JAK1/STAT1/3 pathway, A CRS cell line (NCC-SCC-89/C) were grafted into NSG mice. Ruxolitinib treatment significantly reduced tumor volume, STAT activation, and ETV1/4/5. In conclusion, we show that the JAK1/STAT1/3 pathway plays a critical role in cooperating with CIC-fusions to drive CRS, providing insight into potential therapeutic avenues for these aggressive tumors.