BackgroundBRAF inhibitor/MEK inhibitor treatment is now approved for the treatment of BRAF V600E altered malignant gliomas, but its optimal timing of use, whether upfront in combination with radiation treatment or at relapse after concomitant and adjuvant temozolomide is better, remains unresolved. We aimed to solve this question using BRAF-altered malignant glioma cell lines.MethodsWe established the NGT41 line harboring BRAF V600E, pTERT C250T, CDKN2A loss from an epithelioid glioblastoma patient, and the NGT245 line harboring KIAA1549::BRAF fusion and CDKN2A loss from a spinal malignant astrocytoma patient. YMG62, YMG89, AM38, DBTRG-05MG cell lines harboring BRAF V600E mutations were also used. The BRAF inhibitors dabrafenib and encorafenib, and MEK inhibitors trametinib and binimetinib were used for in vitro experiments.ResultsNGT41 and NGT245 were MGMT positive and negative, respectively, but both cell lines were resistant to temozolomide treatment. Both cell lines were sensitive to BRAF inhibitor and/or MEK inhibitor treatment. Inhibition of phosho-ERK1/2 and phospho-MEK1/2 were observed after combined encorafenib/binimetinib treatment.DiscussionThese preliminary results suggest that BRAF/MEK inhibitors sensitize BRAF-altered glioma cell lines to radiation treatment and thus should be used upfront in conjunction with radiation. This project was funded by JSNO Research Grant for fiscal year 2023.

SummaryBackgroundIntraspinal tumors (ISTs) pose diagnostic challenges due to their complex anatomy and reliance on subjective clinical imaging interpretation, while artificial intelligence-based methods offer significant potential for non-invasive ISTs diagnosis. We aimed to develop and validate an MRI-based deep learning model for IST differentiation.MethodsWe conducted a retrospective study across three hospitals in China between January 2010 and July 2025. This retrospective study included 1004 patients diagnosed with ISTs, categorized into Schwannoma (SCN), Meningioma (MNG), Astrocytoma (AST), Ependymoma (EPN), and Metastasis (MET). Patients from Center 1 (n = 723) formed the internal dataset, which was randomly divided into training, validation and internal test sets at a 7:1:2 ratio. Additionally, 281 patients from Centers 2 and 3 were used as an external test set. All patients underwent preoperative spinal MRI, including sagittal T1-weighted (T1W), T2-weighted (T2W), T2 fat-suppressed (T2FS) and axial T2W sequences. We proposed the ISMF-Net that integrates features from sequences and clinical data to differentiate ISTs. Diagnostic improvements with model assistance were evaluated through an observer study involving radiologists of different levels of experience.FindingsAmong 1004 patients, 22.6% had SCN, 21.8% had MNG, 14.9% had AST, 18.2% had EPN, and 22.5% had MET. The proposed ISMF-Net achieved micro-ACC of 0.859 [0.827, 0.889], 0.849 [0.826, 0.874], and 0.821 [0.801, 0.841] on the validation, internal test, and external test sets, respectively, outperforming existing methods. The highest performance was observed for SCN (F1: 0.905 [0.879, 0.930]–0.940 [0.910, 0.968]), while MET showed lower performance (F1: 0.757 [0.724, 0.790]–0.804 [0.746, 0.858]). Model assistance significantly improved diagnostic performance across all radiologists, with junior radiologists benefiting the most, showing increases of 7.9%, 20.1% and 4.9% in accuracy, sensitivity, and specificity, respectively. Additionally, preference analysis confirmed strong alignment between the model's predictions and radiologists' diagnostic tendencies.InterpretationThis study proposes a multi-modal DL approach integrating MRI and clinical data to improve IST diagnosis, providing a valuable tool for enhancing diagnostic accuracy in clinical practice.FundingThis study was funded by the General Program from Department of Education of Liaoning Province (JYTMS20230132), the National Natural Science Foundation of China (82304235) and the 10.13039/501100002858China Postdoctoral Science Foundation (2024M753641).

Abstract Oligodendrogliomas (OL) and Astrocytomas (AS), typically affect young adults and are characterized by the mutation of the isocitrate dehydrogenase genes (IDH1/2). While IDH-mutant gliomas are of good initial prognosis, they relapse almost systematically in higher-grade gliomas. These tumors display large intra- and inter-patient heterogeneity hallmarked by dynamic adaptation of tumor cell phenotypes and microenvironment across tumors and grades. However, the spatial organization and interactions between cell-types from the brain tumor microenvironment remain elusive and is required to better understand tumor growth and relapse. Here, we profiled in-depth IDH-mutant gliomas with Visium spatial transcriptomics across 32 areas from 20 patients that underwent surgical resection. Our cohort spans tumors of grade II to IV in WHO 2021 classification. We implement state-of-the art bio-informatics methods to decipher spatial heterogeneities such as chromosomal alterations, spatial domains, cell-type distribution and cell-cell interactions. With copy number variation inference, we retrieve stereotypical chromosomal alteration describe in the literature and classify spot according to their malignant content to identify tumor core areas compare to infiltrated cortex. By performing cell-type deconvolution with cell2location, we provide a map of IDH-mutant tumors microenvironment showing tumor cell states and brain tumor microenvironment cell spatial distribution and relationships. We then use machine learning and spatial statistics to identify recurrent patterns across samples and compare their spatial distribution across IDH-mutant subtypes and grades. With matrix factorization technique, we identify cellular niches defined by recurrent cell-type co-localizations found across IDH-mutant gliomas. We also identify clusters enriched in hypoxia programs that are linked to the specific cell-type compositions uncovered with deconvolution. Finally, we provide a spatially resolved landscape of the cell-cell interaction of IDH-mutant gliomas where we identify communication patterns between cellular niches. To summarize, our study provides a novel comprehensive landscape of IDH-mutant glioma spatial organisation across subtypes and grades.

Abstract Tuberous sclerosis complex (TSC) is a genetic disorder resulting from mutations in the TSC1/TSC2 tumor suppressor genes. It causes benign tumors in multiple organs including the brain with cortical tubers, subependymal nodules, white matter abnormalities, and low-grade subependymal giant cell astrocytomas (SEGAs). Reported cases of malignant gliomas in TSC patients, with two new cases, are presented below. A 49-year-old woman, with TSC, cortical tubers, epilepsy, and taking everolimus for renal angiomyolipoma, presented with new headaches; a glioblastoma was resected. She underwent radiation, temozolomide, and bevacizumab. She is stable 12 months after diagnosis. A 57-year-old male, with a history of TSC, epilepsy, and cortical tubers, presented with new headaches. An enhancing brain mass was resected as a glioblastoma. He experienced mesenteric ischemia and bowel infarction and died three weeks later. A 22-month-old male, with a malignant gemistocytic astrocytoma, diagnosed after presenting with lethargy and vomiting, survived five months after surgery and radiotherapy. A 17-year-old male had upper motor neuron signs, from a glioblastoma, which was resected and radiated. A 26-year-old male developed glioblastoma eight years after radiation and excision of a SEGA. He died four months after surgery and chemotherapy. A 5-year-old male, with TSC2, lived three years following surgery, chemotherapy, radiotherapy, and mTOR inhibition for glioblastoma. A 33-year-old female presented with behavioral changes and hemiparesis; a glioblastoma was resected. A 58-year-old male, with confusion, dysphasia, and hemiparesis, had a glioblastoma and survived one month. An 11-month-old male had a SEGA resected which recurred as a malignant SEGA; he remained recurrence-free five years after chemotherapy. A 54-year-old male, with TSC1, developed visual loss secondary to a glioblastoma. He received surgery, radiotherapy, chemotherapy, bevacizumab, and anti-PD-L1 antibody, surviving 12 months post-surgery. These cases raise the question of whether malignant gliomas, in patients with TSC, may be more frequent and appear earlier.

Abstract BACKGROUND Isocitrate dehydrogenase-mutated (IDHmut) gliomas, frequently diagnosed at stage II, often recur at higher stages with increased aggressiveness. However, the molecular mechanisms driving these recurrences remain poorly understood, particularly given their highly variable timeline—occurring within months in some cases and years in others. This study aims to analyze the transcriptomes and methylomes of primary and recurrent tumors to identify patterns that could provide insight into the factors influencing tumor progression. MATERIAL AND METHODS To date, our study has included six astrocytomas (AC) and 24 oligodendrogliomas (ODG), all exhibiting at least one recurrence (19 patients). Among them, eight patients experienced two recurrences, while three had three recurrences. DNA and RNA were extracted from formalin-fixed, paraffin-embedded tumor sections marked by a pathologist to ensure a high tumor cell content (>70%). IDH status was determined using Sanger sequencing. RNA samples underwent transcriptome analysis using Clariom D microarrays, followed by processing with TAC 4.0 software for data analysis. Additionally, methylome profiling is currently being conducted using Illumina 935k methylation arrays, with findings to be presented at a later stage. RESULTS IDH mutation was detected in all primary tumor samples; however, in two ODG cases, the mutation was lost at the second recurrence. Differential gene expression analysis and unsupervised hierarchical clustering of all primary and recurrent samples identified four distinct clusters—two corresponding to primary tumors and two to recurrent cases. When analyzed by diagnosis, AC exhibited a clear separation between primary and recurrent tumors, with an increasing number of differentially expressed genes as recurrence progressed. Approximately 50% of differentially expressed genes were non-coding, with 3.46% belonging to miRNA precursors and 2.69% being small RNAs. In contrast, oligodendrogliomas showed no distinct differences in expression pattern when comparing primary and recurrent samples. CONCLUSION Transcriptome profiling revealed progressive alterations in recurrent AC cases, while ODG recurrence appears to follow a different trajectory. Further methylome analysis may offer deeper insights into the mechanisms driving glioma progression, and the inclusion of additional samples and treatment data could further enhance these findings.

Spinal cord astrocytoma (SCA) is the most common type of spinal glioma in children and the second most common in adults. The standard treatment involves surgical resection, with adjuvant radiotherapy and chemotherapy being considered depending on the degree of malignancy. However, for malignant SCA, especially diffuse midline gliomas (DMG) with H3 K27M alterations, the relationship between resection extent and patient prognosis remains a topic of debate. The primary goal of surgery is to maximize tumor removal while minimizing damage to spinal cord function. Due to the complexity of spinal structures and the diffuse nature of these tumors, complete resection is often challenging. The choice of surgical strategy significantly impacts long-term survival and quality of life, highlighting the importance of in-depth studies on surgical approaches and tumor biology. This review provides an overview of recent advancements in understanding the role of surgical resection extent in malignant SCA, with a focus on the underlying biological factors, aiming to guide clinicians in practice. Additionally, we emphasize the importance of comprehensive treatment, including postoperative radiotherapy, chemotherapy, and novel therapies, to improve survival rates and overall clinical outcomes.

Tissue hypoxia is commonly observed in head cancers and contributes to both molecular and functional changes in tumour cells. It is known to stimulate erythropoiesis, angiogenesis, and metabolic alterations within tumour cells. Glioblastoma, a type of brain tumour, is characterized by rapid proliferation and aggressive growth. Recent studies have indicated that natural products may hold potential as components of cancer therapy. Among these, Polish propolis and its active compound, quercetin, have demonstrated promising anti-cancer properties. The aim of this study was to evaluate the concentrations of selected cytokines—specifically IL-6, IL-9, vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF-BB), interferon gamma-induced protein 10 (IP-10), and monocyte chemoattractant protein-1 (MCP-1)—produced by astrocytes of the CCF-STTG1 cell line. The cytotoxic effects of ethanolic extract of propolis (EEP) and quercetin were assessed using the MTT assay. Astrocytes were stimulated with lipopolysaccharide (LPS, 200 ng/mL) and/or IFN-α (100 U/mL), followed by treatment with EEP or quercetin (25–50 µg/mL) under hypoxic conditions for two hours. Cytokine concentrations were measured using the xMAP Luminex Multiplex Immunoassay and the Multiplex Bead-Based Cytokine Kit. Our study demonstrated that Polish propolis and its component quercetin modulate the tumour microenvironment in vitro, primarily by altering the levels of specific cytokines. The HCA analysis revealed that IL-6 and MCP-1 formed a distinct cluster at the highest linkage distance (approximately 100% of Dmax), suggesting that their expression patterns are significantly different from those of the other cytokines and that they are more similar to each other than to the rest. PCA analysis showed that EEP-PL (50 μg/mL) with IFN-α and EEP-PL (50 μg/mL) with LPS exert similar activities on cytokine secretion by astrocytes. Similar effects were demonstrated for EEP-PL 50 μg/mL + LPS + IFN-α, EEP-PL 25 μg/mL + IFN-α and EEP-PL 25 μg/mL + LPS + IFN-α. Our findings suggest that Polish propolis and quercetin may serve as promising natural agents to support the treatment of stage IV malignant astrocytoma. Nonetheless, further research is needed to confirm these results.

Malignant astrocytomas are aggressive primary brain tumors characterized by extensive hypoxia-induced, mitochondria-dependent changes such as altered respiration, increased chymotrypsin-like (CT-L) proteasome activity, decreased apoptosis, drug resistance, stemness, and increased invasiveness. Mitochondrial Lon Peptidase 1 (LonP1) overexpression and increased CT-L proteasome activity are biomarkers of an aggressive high-grade phenotype and found to be associated with recurrence and poor patient survival. In preclinical models, small molecule agents targeting either LonP1 or the proteasome CT-L activity have anti-astrocytoma activity. Here, we present evidence that the dual inhibition of LonP1 and CT-L proteasome activity effectively induces ROS production, leading to apoptosis in malignant astrocytoma established cell lines and patient-derived glioma stem cell-like cultures. We also evaluated a novel small molecule, BT317, derived from the coumarinic compound 4 (CC4) using structure-activity modeling, which we found to inhibit both LonP1 and CT-L proteasome activity. Using gain- and loss-of-function genetic models, we discovered that LonP1 is both necessary and sufficient to drive BT317 drug sensitivity in established and patient-derived glioma stem-like cells by generating ROS and inducing apoptosis. In vitro, BT317 had activity as a single agent but, more importantly, enhanced synergy with the standard of care commonly used chemotherapeutic temozolomide (TMZ). In an orthotopic xenograft astrocytoma model, BT317 crossed the blood-brain barrier, showed selective activity at the tumor site, and demonstrated therapeutic efficacy as a single agent and combined with TMZ. BT317 defines an emerging class of LonP1 and CT-L inhibitors that exhibited promising anti-tumor activity and could be a potential candidate for malignant astrocytoma therapeutics. SIMPLE SUMMARY: Malignant astrocytoma patients have poor clinical outcomes, and novel treatments are needed to limit tumor recurrence and improve their overall survival. These tumors have a malignant phenotype mediated by altered mitochondrial metabolism, abnormal protein processing, and adaptation to hypoxia. We have previously published that astrocytomas are especially vulnerable to proteasome inhibitors as well as to inhibitors of the mitochondrial Lon Peptidase 1 (LonP1), but the effect of combining the two strategies has not been reported. Here, we present evidence that the dual inhibition of LonP1 and Chymotrypsin-like (CT-L) proteasome activity effectively induces cellular reactive oxygen species (ROS) production, leading to apoptosis in malignant astrocytoma established cell lines and patient-derived glioma stem cell-like cultures. We developed BT317, a small molecule dual inhibitor, which crosses the blood-brain barrier and shows strong synergy with the standard of care, temozolomide (TMZ), in the astrocytoma cell lines independent of their isocitrate dehydrogenase (IDH) profile and in an orthotopic glioma murine model. This preclinical study demonstrated the potential of dual LonP1 and CT-L proteasome inhibition as a novel therapeutic strategy for malignant astrocytoma and provides insight for future clinical translational studies alone or in combination with other chemotherapies.

Aim. To create a collection of plasma samples of patients with brain tumors (BTs) for the development of a diagnostic microRNA (ribonucleic acid) panel of glial tumors.Material and methods. Plasma samples of patients with benign and malignant BTs were obtained by double centrifugation of whole blood and then frozen at -75оС.Fifty-nine RNA samples isolated from blood plasma were analyzed by next-generation sequencing (NGS).Results. Currently, the biobank contains samples from 339 patients with primary and secondary BTs and 10 control group individuals (698 samples — 2 plasma aliquots per individual), including 143 men and 206 women. The age of the patients ranged from 19 to 91 years (median — 56 years). Primary BTs (41%) included two following groups: benign (33,7%) and malignant (66,3%). Meningiomas constituted the bulk (91%) of the benign BTs. Among the malignant tumors, glioblastomas (46,7%) and astrocytomas (41,6%) prevailed, while oligodendrogliomas and ependymomas accounted for only 9,1 and 2,5%, respectively. Secondary BTs (59%) are represented by recurrent glial tumors (92,5%) and metastatic tumors (7,5%) of lung cancer (71,4%) and breast cancer (28.6%). A protocol for the primary preparation of liquid biopsy samples was implemented, which made it possible to obtain high-quality deoxyribonucleic acid libraries for the selected microRNA profiling platform.Conclusion. The creation of a plasma sample collection is the basis for searching circulating biomarkers of BTs.

Our extensive basic research on photodynamic therapy (PDT) application in models of intracranial malignant astrocytoma led to its clinical application for intracranial malignant astrocytoma in Japan. Having considered the safety and effectiveness of this pathology, we initiate a first-in-human clinical study of PDT for spinal cord malignant astrocytoma. This study has an open-label, single-arm design. The initial follow-up period is 12 months, at the end of which we will quantify survival after PDT for spinal cord malignant astrocytoma as primary objective. The secondary objective is to quantify the overall progression-free survival of treated patients and the percentage of patients surviving 6 months after PDT without recurrence. Twenty patients suffering from spinal cord malignant astrocytoma will be recruited. In particular, 10 of those should be newly diagnosed World Health Organization grade 4. After obtaining consent, each patient will receive a single intravenous injection of talaporfin sodium (40 mg/m2) 1 day before tumor resection. One day after completing tumor removal, the residual lesion and/or resection cavity will be irradiated using a 664-nm semiconductor laser with a radiation power density of 150 mW/cm2 and a radiation energy density of 27 J/cm2. The procedure will be performed 22–26 hours after talaporfin sodium administration. This study protocol has been reviewed and approved by the Certified Committee in the Japanese Ministry of Health, Labor, and Welfare University Hospital Medical Information Network Clinical Trials Registry (Japan Registry of Clinical Trials number, jRCT2021220040).

Objectives We present the case of a 37-year-old female who underwent partial resection in 2018 for a diffuse fibrillary astrocytoma (WHO II) that invaded almost the entire right cerebral hemisphere. The patient followed conventional radiotherapy and chemotherapy. She presents after 6 years of regularly follow-ups with left hemiparesis, intracranial hypertension syndrome and tumor recurrence on MRI. The patient underwent another surgical intervention and the new histopathological diagnosis was diffuse astrocytoma grade IV. Therapeutic options for these patients are limited considering the fact that a gross total resection or a conventional re-irradiation could impact the quality of life. Therefore, exploring new therapeutic methods, such as targeted molecular therapy like EGFR antagonists or proteasome inhibitors, or proton therapy, should be considered. Material and Methods We conducted extensive research in two public medical databases for information related to the molecular pathways and management of primary and recurrent malignant astrocytoma and relevant articles were selected. Subsequently, we correlated this information with our direct experience in our case and discussed the observed results. Results Treatment modalities for these patients include reintervention, re-irradiation and second line chemotherapeutics. In relapsing cases the goal of reintervention is both to alleviate symptoms and obtain tumoral tissue for immunohistochemical analysis for identification of the new mutations. Conventional re-irradiation for large lesions carries high risks of producing both short-term and long-term side effects, impacting the quality of life. Alternatively, proton therapy minimizes the risk of adverse events due to Bragg peak reducing the irradiation of the surrounding tissue. Conclusions Genetic characterization of these lesions can facilitate targeted molecular therapy and help in establishing the prognosis. Re-irradiation of malignant astrocytomas with proton therapy is an effective treatment measure allowing for comparable tumor control to conventional radiotherapy.

Objectives: The recent World Health Organization classification has recommended the usage of surrogate immunohistochemical markers for molecular classification of gliomas. However, only a few studies have attempted to study the expression of the entire panel of markers. The current study was undertaken to study the association of recognized surrogate immunohistochemical markers (isocitrate dehydrogenase 1 [IDH-1], alpha-thalassemia mental retardation X-linked [ATRX] and p53) in different histological lineages and grades of adult gliomas. Materials and Methods: This study was conducted on 118 cases of adult gliomas diagnosed on histopathology over a 2-year duration in a tertiary care hospital. The expression of surrogate immunohistochemistry markers (IDH-1, ATRX, and p53) in these cases was studied. Statistical analysis: Descriptive statistical analysis with the Statistical Package for the Social Science system version 17.0. Results: The frequency of IDH-1 positivity was significantly higher in oligodendrogliomas (OG: 76.5%; oligoastrocytoma: 100%) versus astrocytoma (AS) (grades 2 and 3: 48.1%). It was also significantly higher in diffuse gliomas (grades 2 and 3) versus glioblastomas (64% vs. 16.9%). Among IDH-mutant diffuse gliomas, ATRX loss was significantly higher in AS versus OGs (84.6% vs. 7.7%). P53 overexpression correlated significantly with histological subtype (AS 2,3: 55.6% vs. OG: 5.9%). Conclusions: The surrogate immunohistochemical panel of IDH-1, ATRX, and p53 showed significant association with distinct histopathological subtypes and is helpful in molecular stratification. Cut-offs of ≥ 10% nuclear positivity for p53 and 50% loss of nuclear ATRX expression showed a good correlation.

Practical Nomograms and Risk Stratification System for Predicting the Overall and Cancer-specific Survival in Patients with Anaplastic Astrocytoma

INTRODUCTION: Since 2016, molecular markers, in particular, mutations in isocitrate dehydrogenase (IDH) 1 and 2, have been introduced as a classifying feature of cerebral gliomas that provided superior prognostication. The search for non-invasive biomarkers of the molecular profile of gliomas is necessary to improve the quality of preoperative diagnostics, identify patients with good and poor prognosis and determine treatment tactics.OBJECTIVE: Was to study the relationship between the IDH genotype of diffuse cerebral gliomas and metabolic biomarkers according to the results of PET/CT with [11C]methionine.MATERIALS AND METHOD: The results of PET/CT with 11C-methionine were identified to a retrospective analysis of 260 patients aged 18 to 75 years (median 40 years) with untreated cerebral glioma. Based on histological and molecular genetic studies of the surgical material including the determination of a mutation in the isocitrate dehydrogenase 1 (IDH1132H) gene, diffuse gliomas were classified according to the 2016 WHO classification of CNS tumors. Metabolic biomarkers included the calculation of tumor-to-brain ratio of 11С-methionine (TBRmax, TBRpeak and TBRmean) as well as the metabolic tumor volume (MTV). Statistics. Non-parametric tests were performed to compare the differences among patient groups. ROC curve analysis was performed to screen the optimal parameter and its best cutoff value for the discrimination of glioma genotype. All data analyses were performed using “Statistica 10,0” and “MedCalc” ststistical software. p-values less than 0.05 were considered statistically significant.RESULTS: According to the 2016 WHO classification astrocytic and oligodendroglial tumors of the adult type were divided into three groups: astrocytic gliomas with a mutation in the IDH1 gene (IDH1 mut) (n=95), astrocytic gliomas without a mutation in the IDH1 gene (IDH1 wild type — IDH1 wt) (n=103), and IDH1-mutant oligodendrogliomas (n=62). Significant differences in all ratios between the three molecular groups of gliomas were established. TBRmax cutoff of 2.27 differentiated between IDH1 wt and IDH1 mut gliomas with a sensitivity of 61% and a specificity of 77% (area under curve — AUC 0.752). When considering subgroups of gliomas that are homogeneous in terms of the IDH1 status or Grade, the dependence of TBR on the glioma histotype and grading was additionally established. In IDH1 mut oligodendrogliomas, TBR was significantly higher than in mutant astrocytomas, and in IDH1 wt astrocytomas, significant differences in TBR were established between Grade 2 and Grade 3–4. TBRmax was not a predictor of glioma type according to the WHO 2016 classification due to significant overlap of individual of TBR values. But TBRmax allowed diagnosing a cluster of malignant gliomas, including glioblastoma and astrocytoma Grade 3 IDH wt, as well as oligodendroglioma Grade 3 IDH1 mut, with a sensitivity of 65% and a specificity of 89% (AUC 0.848) at a cutoff of TBR=2.7. A strong correlation between the three tumor-to-brain ratios allows any ratio to be used in diagnostics. There were no significant differences in MTV between molecular types of gliomas.DISCUSSION: Distinguishing glioma types based on the 2016 WHO classification of the CNS tumors on the basis of 11Cmethionine uptake seems to be not reliable due to many factors that affect its uptake. In astrocytomas high TBR is associated with malignant grade and wild type IDH1 gene. However, the lack of differences in TBR between these astrocytomas and Grade 3 IDH1-mutant oligodendrogliomas does not allow one to predict the IDH1 status of the tumor in the absence of other radiological signs of the glioma histotype. The absence of differences in TBR between Grade 2 and Grade 3 astrocytomas IDH1 mut supports the view that they are considered as a single subgroup of lower grade gliomas. CONCLUSION: PET/CT with 11C-methionine has limited potential to assess the IDH status of diffuse gliomas. High TBR is associated with malignant glioma with wild-type IDH1 gene or oligodendroglial structure.

Abstract While isocitrate dehydrogenase (IDH) wild-type and mutant malignant astrocytoma (IDHwt, IDHmt) are diffuse CNS tumors that have a high degree of parallelism with one another, including microvascular proliferation and necrosis, the IDHwt tumors clinically presents with a higher tumor grade and thus poorer prognosis and survival rate. Isocitrate dehydrogenase mutation (IDH) hinders the hypoxia response in gliomas and promotes an advantageous reduction in both tumor growth and treatment resistance. Since recurrence is high, adequate characterization and identification of potential novel molecular targets in IDHmt mutant diffuse glioma is integral for developing new therapeutic strategies for better control of tumor burden and, thus, improved outcomes. Our previous published work has shown that the hypoxia responsive LONP1 mitochondrial protease is involved in glioma growth and treatment resistance and that LONP1 inhibitors can augment the effect of chemotherapy in IDHwt models. Here, we highlight the downstream activity of LONP1 via the NRF2 pathway and how synergistically, along with the IDH mutation, LONP1 overexpression can promote the subsequent proneural to mesenchymal transition (PMT) induced by stress and other tumor microenvironment signals. By characterizing the interplay between LONP1 and IDH mutation in in-vitro models, we demonstrate that oxidative stress modulates both PMT and TMZ drug resistance. When translated to an in-vivo patient-derived, intracranial orthotopic xenograft model, LONP1 overexpression is associated with decreased survival.Based on our findings, future clinical translation includes the possibility of using LONP1 as a novel target to optimize the standard of care treatment in IDH mutant diffuse astrocytoma. Citation Format: Christopher Douglas, Shashi Jain, Naomi Lomeli, Thao Vu, James Pham, Daniela A. Bota. Targeting Lon protease as novel strategy to treat aggressive IDH mutant diffuse malignant astrocytoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4731.

<b>Abstract ID 29107</b> <b>Poster Board 440</b> Glioblastoma multiforme (GBM), a grade IV malignant astrocytoma, is a highly proliferative primary malignant brain tumor with a dismal 5-year survival rate of ∼5%. Current treatment strategies including surgery, radiation, and chemotherapy have limited success due to resistance to the standard chemotherapeutic temozolomide (TMZ). Moreover, other drug therapies have difficulty permeating the blood brain barrier, and tumor invasion in brain regions makes surgical removal challenging. The dire need of a new chemotherapeutic has thus led us to repurpose an FDA-approved drug stiripentol (STP) with lactate dehydrogenase (LDH) as its putative target. LDH is a key glycolytic enzyme in the rewiring of cancer metabolism. In fact, decreased expression of an LDH isoform has been shown to reduce metastasis and increase apoptosis in GBM. Our previous study demonstrated efficacy of STP in U87, U138, LN229 and SW1088 GBM cells: STP inhibited proliferation, colony-forming potential, and 3D spheroid growth. STP also caused G2/M phase arrest of the cell cycle. We also found STP to be effective against TMZ-resistant cells and STP had a relatively high safety profile in normal human dermal fibroblast cells. Our current studies are mainly focused on elucidating the targets and mechanism of action of STP in GBM. We will study whether LDH and GABA receptors are direct or indirect targets of STP using silencing and overexpression-based strategies. A phospho-kinase array will aid us in identifying pathways implicated in STP’s mechanism of action. In addition, we will study the effect of STP on the Warburg effect and other metabolic alterations in GBM cells. Seahorse assay for extracellular acidification rate (ECAR) and oxygen consumption rate (OCR), as well as mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) generation assays will be used to elucidate the metabolic effects of STP in GBM cells. Additionally, we will determine the mechanism of cell death mediated by STP’s actions. The results of our study can elucidate the mechanistic basis of STP’s anticancer effects and help in developing novel chemotherapeutics for GBM. This research was supported by an award from the National Institute of General Medical Sciences of the National Institutes of Health under Award Number R16GM145557 and SC2GM125550 and by funds from the College of Pharmacy and Health Sciences, St. John’s University, NY

Astrocytomas include a wide range of tumors with unique mutations and varying grades of malignancy. These tumors all originate from the astrocyte, a star-shaped glial cell that plays a major role in supporting functions of the central nervous system (CNS), including blood-brain barrier (BBB) development and maintenance, water and ion regulation, influencing neuronal synaptogenesis, and stimulating the immunological response. In terms of epidemiology, glioblastoma (GB), the most common and malignant astrocytoma, generally occur with higher rates in Australia, Western Europe, and Canada, with the lowest rates in Southeast Asia. Additionally, significantly higher rates of GB are observed in males and non-Hispanic whites. It has been suggested that higher levels of testosterone observed in biological males may account for the increased rates of GB. Hereditary syndromes such as Cowden, Lynch, Turcot, Li-Fraumeni, and neurofibromatosis type 1 have been linked to increased rates of astrocytoma development. While there are a number of specific gene mutations that may influence malignancy or be targeted in astrocytoma treatment, O 6-methylguanine-DNA methyltransferase (MGMT) gene function is an important predictor of astrocytoma response to chemotherapeutic agent temozolomide (TMZ). TMZ for primary and bevacizumab in the setting of recurrent tumor formation are two of the main chemotherapeutic agents currently approved in the treatment of astrocytomas. While stereotactic radiosurgery (SRS) has debatable implications for increased survival in comparison to whole-brain radiotherapy (WBRT), SRS demonstrates increased precision with reduced radiation toxicity. When considering surgical resection of astrocytoma, the extent of resection (EoR) is taken into consideration. Subtotal resection (STR) spares the margins of the T1 enhanced magnetic resonance imaging (MRI) region, gross total resection (GTR) includes the margins, and supramaximal resection (SMR) extends beyond the margin of the T1 and into the T2 region. Surgical resection, radiation, and chemotherapy are integral components of astrocytoma treatment.

Infiltration is a life-threatening growth pattern in malignant astrocytomas and a significant cause of therapy resistance. It results in the tumor cell spreading deeply into the surrounding brain tissue, fostering tumor recurrence and making complete surgical resection impossible. We need to thoroughly understand the mechanisms underlying diffuse infiltration to develop effective therapies. We integrated in vitro and in vivo functional assays, RNA sequencing, clinical, and expression information from public data sets to investigate the role of ADAM23 expression coupling astrocytoma's growth and motility. ADAM23 downregulation resulted in increased infiltration, reduced tumor growth, and improved overall survival in astrocytomas. Additionally, we show that ADAM23 deficiency induces γ-secretase (GS) complex activity, contributing to the production and deposition of the Amyloid-β and release of NICD. Finally, GS ablation in ADAM23-low astrocytomas induced a significant inhibitory effect on the invasive programs. Our findings reveal a role for ADAM23 in regulating the balance between cell proliferation and invasiveness in astrocytoma cells, proposing GS inhibition as a therapeutic option in ADAM23 low-expressing astrocytomas.

Tumor cells thrive by adapting to the signals in their microenvironment. To adapt, cancer cells activate signaling and transcriptional programs and migrate to establish micro-niches, in response to signals from neighboring cells and non-cellular stromal factors. Understanding how the tumor microenvironment evolves during disease progression is crucial to deciphering the mechanisms underlying the functional behavior of cancer cells. Multiplex immunohistochemistry, spatial analysis and histological dyes were used to identify and measure immune cell infiltration, cell signal activation and extracellular matrix deposition in low-grade, high-grade astrocytoma and glioblastoma. We show that lower grade astrocytoma tissue is largely devoid of infiltrating immune cells and extracellular matrix proteins, while high-grade astrocytoma exhibits abundant immune cell infiltration, activation, and extensive tissue remodeling. Spatial analysis shows that most T-cells are restricted to perivascular regions, but bone marrow-derived macrophages penetrate deep into neoplastic cell-rich regions. The tumor microenvironment is characterized by heterogeneous PI3K, MAPK and CREB signaling, with specific signaling profiles correlating with distinct pathological hallmarks, including angiogenesis, tumor cell density and regions where neoplastic cells border the extracellular matrix. Our results also show that tissue remodeling is important in regulating the architecture of the tumor microenvironment during tumor progression. The tumor microenvironment in malignant astrocytoma, exhibits changes in cell composition, cell signaling activation and extracellular matrix deposition during disease development and that targeting the extracellular matrix, as well as cell signaling activation will be critical to designing personalized therapy.

Abstract OBJECTIVE RTOG 9802 demonstrated improved survival using chemoradiotherapy (CRT) over radiotherapy (RT) alone for WHO Grade II gliomas (LGG) using PCV with RT. We analyze our retrospective dataset of predominantly temozolomide (TMZ)-based CRT in LGG patients who would have been eligible for RTOG 9802. METHODS Retrospective review of LGG patients (2000–2017) treated at a single institution (67 patients). Histologies included oligodendroglioma(OD), astrocytoma(AC) or astrocytoma (OA). Those who received upfront RT +/- chemotherapy were included. The CRT cohort (n=40) consisted primarily of TMZ (n=36) administered concurrently with RT. 27 patients received RT alone. RT for both cohorts consisted of a median dose of 54 Gy (range 50.4 - 54 Gy). 65/67 patients had “high risk” LGG as defined by RTOG 9802 criteria. Kaplan Meier analysis was used to assess overall survival (OS) and progression free survival (PFS). RESULTS 5-year PFS for patients receiving CRT was 64% vs. 44% in those receiving RT alone (log rank p=0.009). Difference in PFS due to chemotherapy was driven by AC histology (57% vs. 21% PFS at 5 years, log rank p=0.002) while OD/OA PFS was not statistically altered (79% vs. 72% PFS at 5 years, p=0.21). 5-year OS for patients receiving CRT was 76% vs. 69% in those receiving RT alone (p=0.11). Cox Proportional Hazards analysis showed that use of upfront CRT (HR=0.4, p=0.009) was the only factor that decreased the risk of earlier progression. CONCLUSION Use of upfront, predominantly TMZ-based CRT, has a PFS benefit over RT alone in a population of WHO grade II gliomas. This benefit appears to be driven by AC histology and also appears to extend beyond the “very high risk” cohort from RTOG 0424 to include the “high risk” group from RTOG 9802.