bluuebunny/crossref_metadata_2025 huggingface dataset:
BIOM-35. IDENTIFICATION AND VALIDATION OF POTENTIAL BIOMARKERS FOR DECITABINE-MEDIATED SENSITIZATION TO TEMOZOLOMIDE IN GLIOBLASTOMA
Authors: Hurtado Thenzing Silva , Inocencio Julio , Mead Andy , Fang Gang , Pai Balagopal , Tsankova Nadejda , Yong Raymund
Published: November 2023

Glioblastoma (GBM) is an aggressive form of brain cancer with limited treatment options and a poor prognosis. Our previous research demonstrated that the DNA hypomethylating agent decitabine (DAC) enhances the sensitivity to temozolomide (TMZ) of a subset of primary GBM cell lines derived from fresh surgical tissue specimens, and that this effect may be mediated by upregulation of DNA mismatch repair genes including MLH1. In this context, we aim to identify additional biomarkers for DAC-mediated sensitization to TMZ with potential clinical utility through in vitro and in vivo experiments. We performed single cell RNA sequencing on three DAC-sensitized and three DAC-desensitized cell lines and found 4 genes that exhibited significant differential expression: DCN, LUM, CRABP2 and NUPR1. We validated these findings using quantitative immunoblots, RT-qPCR and immunohistochemistry, finding that NUPR1 protein expression levels varied most significantly between DAC-sensitized and desensitized GBM tissues. Long-range direct methylation sequencing of non-amplified genomic DNA enriched using CRISPR/Cas9 demonstrated several CpG sites within the 4 genes that may be predictive of TMZ sensitization response after treatment with DAC. Finally, we performed mouse survival experiments using orthotopic patient-derived xenografts (PDXs) of the six GBM cell lines, with preliminary results showing that in selected PDX survival was significantly increased with combined DAC-TMZ versus TMZ monotherapy as predicted by in vitro assays. In conclusion, our study demonstrates that combining DAC with TMZ may be a potential treatment strategy for GBM in a subset of patients. There likely exist several biomarkers that can be used at the time of diagnosis, alone or in combination, to predict the response to epigenetic preconditioning using DAC for TMZ sensitization, which will be necessary for optimal patient selection in an early phase clinical trial. Further data and validation studies are necessary to strengthen these findings and to confirm their clinical relevance.
BIOM-46. STANDARDIZATION OF LIQUID BIOPSY FOR PEDIATRIC DIFFUSE MIDLINE GLIOMA USING DDPCR
Authors: Li Daphne , Bonner Erin , Huang Tina , Koschmann Carl , Nazarian Javad , Saratsis Amanda
Published: November 2023

BACKGROUND

Diffuse midline glioma (DMG) is a highly morbid pediatric brain tumor. Up to 80% of DMGs harbor mutations in histone H3-encoding genes, associated with poor prognosis. We previously showed the feasibility of detecting H3 mutations in circulating tumor DNA (ctDNA) in the liquid biome of children diagnosed with DMG. However, detection of low levels of ctDNA is highly dependent on platform sensitivity and sample type. To address this, we optimized ctDNA detection sensitivity and specificity across two commonly used digital droplet PCR (ddPCR) platforms (RainDance and BioRad), and validated methods for detecting H3F3A c.83A >T (H3.3K27M) mutations in DMG CSF, plasma, and primary tumor specimens across three different institutions.

METHODS

DNA was extracted from H3.3K27M mutant and H3 wildtype (H3WT) specimens, including H3.3K27M tumor tissue (n = 4), CSF (n = 6), plasma (n = 4), and human primary pediatric glioma cells (H3.3K27M, n = 2; H3WT, n = 1). ctDNA detection was enhanced via PCR pre-amplification and use of distinct custom primers and fluorescent LNA probes for c.83 A >T H3F3A mutation detection. Mutation allelic frequency (MAF) was determined and validated through parallel analysis of matched H3.3K27M tissue specimens (n = 3).

RESULTS

We determined technical nuances between ddPCR instruments, and optimized sample preparation and sequencing protocols for H3.3K27M mutation detection and quantification. We observed 100% sensitivity and specificity for mutation detection in matched DMG tissue and CSF across assays, platforms and institutions.

CONCLUSION

ctDNA is reliably and reproducibly detected in the liquid biome using ddPCR, representing a clinically feasible, reproducible, and minimally invasive approach for DMG diagnosis, molecular subtyping and therapeutic monitoring.
BIOM-63. PROTEOMIC BASED PROFILING OF CSF FOR CNSL MANAGEMENT
Authors: Aastha Aastha , Wilding Hannah , Khan Shahbaz , Mikolajewicz Nicholas , Ignatchenko Vladimir , De Macedo Filho Leonardo Jose Monteiro , Bhanja Debarati , Heebner Madison , Glantz Michael , Mansouri Alireza , Kislinger Thomas
Published: November 2023

Central nervous system lymphoma (CNSL) is a rare subtype of non-Hodgkin lymphoma, primarily affecting the brain and spinal cord. CNSL exhibits a dismal prognosis, as reflected by a low 5-year survival rate of 30%, with the current standard of care. The advent of multi-agent intrathecal chemotherapy (MAITC) in conjunction with systemic therapy has demonstrated encouraging outcomes, enhancing both progression-free survival and overall survival in patients with CNSL. Given the potential morbidity associated with MAITC, identification of minimally-invasive biomarkers for guiding patient management are necessary. Leveraging the longitudinal, large volume of Cerebrospinal fluid (CSF) afforded through our MAITC program, the objective of this study is to identify CSF-based proteomic biomarkers that can serve as reliable indicators of MAITC treatment response and CNSL management. Patient-matched CSF samples from the Penn State Health Neuroscience biorepository were banked at pre- and post-therapeutic endpoint in 22 primary and 36 secondary CNSL patients. The samples were profiled using high-throughput fluid sample protocol coupled with mass-spectrometry that only requires 30 μl of CSF. More than 1000 unique proteins were detected using shotgun proteomics, and 797 proteins were present in 70% of the analyzed samples, which were used for downstream analysis. We were able to effectively discriminate between primary and secondary CNSL based on protein abundance. Furthermore, the findings suggest significant changes in the cellular processes related to glycoprotein metabolism and redox signalling in response to the treatment, indicating a potential impact on protein modification and the cellular response to oxidative stress. Our comprehensive, pathway-level analysis uncovered significant molecular alterations, shedding light on their potential prognostic significance in the context of CNS lymphoma. Future work is underway to identify biomarker signatures that would predict optimal response to MAITC therapy, exhibiting potential to improve clinical decision making.
BIOM-64. A PROGNOSTIC SCORING SYSTEM FOR IMMUNODEFICIENCY-ASSOCIATED PRIMARY CNS LYMPHOMAS: AN INTERNATIONAL MULTI-CENTER STUDY
Authors: Karschnia Philipp , Traub Benjamin-Leon , Doubrovinskaia Sofia , Richter Benjamin , Seidel Sabine , Kuschel Luis , Hinz Felix , Rejeski Kai , Winter Sebastian F , Müller Katharina , Quach Stefanie , Herold-Mende Christel , Kessler Tobias , Sahm Felix , Schlegel Uwe , Platten Michael , Dietrich Jorg , von Baumgarten Louisa , Baehring Joachim , Wick Wolfgang , Kaulen Leon
Published: November 2023

BACKGROUND

Immunodeficiency-associated (ID-) primary CNS lymphomas (PCNSL) were introduced as a distinct entity in the 2021 World Health Organization classification of brain tumors. Given their rarity, larger clinical studies and prognostic models to guide management are lacking.

METHODS

PCNSL, newly diagnosed between 2004-2023 at six centers in the USA and in Germany, were retrospectively analyzed for concurrent immunodeficiency. Clinical, radiological, and pathological data were collected and assessed for prognostic significance using univariate and multivariate analyses.

RESULTS

Among 1112 patients with newly diagnosed PCNSL, 93 (8.4%) were identified as ID-PCNSL. Median age at diagnosis was 57 years and most tumors (66%) stained positive for Epstein-Barr virus (EBV). In addition to immune reconstitution, tumor-directed treatments were administered in 91/93 patients. These included chemotherapy (87%), radiation (25%), and autologous stem cell transplantation (14%). Outcome varied with a median overall survival (OS) of 46 months (range: 1-206 months). Age ≥ 60 years, Karnofsky performance status (KPS) < 70, EBV positivity, and non-rituximab or -methotrexate-based chemotherapy were associated with shorter OS on multivariate analysis adjusting for clinical and demographic factors. A prognostic scoring system was designed based on the sum of treatment-unrelated (age, KPS, EBV) unfavorable factors. The resulting score was highly prognostic and stratified ID-PCNSL into four subgroups: median OS was not reached, 90, 26, and 1 months (p < 0.0001) in cases with zero, one, two, or three unfavorable factors, respectively. Prognostic value was retained when limiting analysis to patients (n = 53), who had received HD-MTX and rituximab combination chemotherapy, with median OS of 98, 90, 46 and 4 months (p < 0.0001).

CONCLUSIONS

EBV was associated with inferior outcome in ID-PNCSL, which may reflect peculiar genetic alterations. An easily-applicable prognostic score based on three variables (age, KPS, EBV) allowed ID-PCNSL stratification into four risk groups. Prospective validation and therapeutic relevance warrant further investigation.
BIOS-04. THE ROLE OF MACHINE LEARNING, PREDICTIVE MODELING, AND DEEP LEARNING IN ASSESSING METABOLIC BIOMARKERS TO IMPROVE PROGNOSTICATION IN GLIOBLASTOMA MULTIFORME
Authors: Kuo Cathleen , Brown Nolan , Gendreau Julian
Published: November 2023

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in the United States, accounting for approximately 56.6% of all gliomas and 47.7% of all primary malignant CNS tumors. The prognosis of GBM is notably grim, with a 1-year relative survival rate of 41.4% and a 5-year survival rate of 5.8% following diagnosis. Recent efforts to identify potential therapeutic targets have utilized tumor omics data integrated with clinical information that leverages machine learning (ML) algorithms. However, there remains a paucity of studies assessing the value of these ML models as prognostic tools in GBM. A systematic search adhering to PRISMA guidelines was conducted to identify all studies describing the use of a ML algorithm involving GBM metabolic biomarkers and each algorithm's accuracy. Ten studies were included for final analysis. They were diagnostic (n = 3, 30%), prognostic (n = 6, 60%), or both (n = 1, 10%), respectively. Most studies analyzed data from multiple databases, while 50% (n = 5) included additional original samples. At least 2,536 data samples were run through a ML algorithm. 27 ML algorithms were recorded with a mean 2.8 algorithms per study. Algorithms were supervised (n = 22, 79%) or unsupervised (n = 6, 21%), and continuous (n = 21, 75%) or categorical (n = 7, 25%). The mean reported accuracy and AUC of ROC was 95.63% and 0.779, respectively. 106 metabolic markers were identified, but only EMP3 was reported in multiple studies. Many studies have identified potential biomarkers for GBM diagnosis and prognostication. These algorithms show promise; although, a consensus on even a handful of biomarkers has not been made. An integration of ML algorithms for biomarker detection combined with radiomics-based tumor imaging will be necessary to ascertain the greatest level of accuracy and precision.
CNSC-04. DIAGNOSIS AND TREATMENT OF PERIPHERAL AND CRANIAL NERVE TUMORS WITH EXPERT RECOMMENDATIONS: AN EUROPEAN NETWORK FOR RARE CANCERS (EURACAN) INITIATIVE
Authors: Pellerino Alessia , Verdijk Robert M , Nichelli Lucia , Andratschke Nicolaus H , Idbaih Ahmed , Goldbrunner Roland
Published: November 2023

BACKGROUND

The 2021 WHO classification of the CNS Tumors identifies as “Peripheral nerve sheath tumors” (PNST) some entities with specific clinical and anatomical characteristics, histological and molecular markers, imaging findings, and aggressiveness. Material and methods. The Task Force has reviewed the evidence of diagnostic and therapeutic interventions, which is particularly low due to the rarity, and drawn recommendations accordingly.

RESULTS

Tumor diagnosis is primarily based on hematoxylin and eosin-stained sections and immunohistochemistry. Molecular analysis is not essential to establish the histological nature of these tumors, although genetic analyses on DNA extracted from PNST (neurofibromas/schwannomas) is required to diagnose mosaic forms of NF1 and SPS. MRI is the gold-standard to delineate the extension with respect to adjacent structures. Gross-total resection is the first choice, and can be curative in benign lesions; however, the extent of resection must be balanced with preservation of nerve functioning. Radiotherapy can be omitted in benign tumors after complete resection and in NF-related tumors, due to the theoretic risk of secondary malignancies in a tumor-suppressor syndrome. Systemic therapy should be considered in incomplete resected plexiform neurofibromas/MPNSTs. MEK inhibitor selumetinib can be used in NF1 children ≥2 years with inoperable/symptomatic plexiform neurofibromas, while anthracycline-based treatment is the first choice for unresectable/locally advanced/metastatic MPNST. Clinical trials on other MEK1-2 inhibitors alone or in combination with mTOR inhibitors are under investigation in plexiform neurofibromas and MPNST, respectively.

CONCLUSIONS

Given the heterogeneity and rarity of these tumors, there is a paucity of well-powered clinical trials, thus it is not possible to generate evidence-based treatment recommendations for non-surgical modalities. However, some clinical trials have been reported on targeted therapies in plexiform neurofibromas of NF1 patients or in heterogenous cohorts of soft-tissue tumors, including MPNSTs, with initial data of efficacy that need to be further investigated.
CNSC-18. DIFFERENTIAL EFFECTS OF NEUROTRANSMITTERS ON THE GROWTH OF GLIOBLASTOMA SUBTYPES
Authors: Irshad Khushboo , Singh Sanjay , Ahmad Khalil Ali , Aghoghovwia Ben , Alnassiry Sama , Lang Frederick , Pan Yuan
Published: November 2023

Glioblastomas are aggressive brain tumors associated with the worst patient prognosis. Neurons play critical roles in modulating the growth of glioblastoma. It has been demonstrated that glutamatergic neurons form bona fide synapses with glioblastoma tumor cells that are critical for tumor cell proliferation and migration. It is less clear whether the activity of other neuronal types influences glioblastoma pathophysiology, especially among the different glioblastoma molecular subtypes. Here, we examined the effects of neurotransmitters on the growth of glioblastoma cells characterized as the classical, proneural and mesenchymal subtypes. Patient-derived glioblastoma cell lines were exposed to varying concentrations of different neurotransmitters for 72 hours and assessed for cell viability using the CCK-8 assay. RESULTS: from the CCK8 assay indicate that acetylcholine and dopamine increase glioblastoma cell growth. Consistent with previous findings, we observed an increase in cell viability in all cell lines after being incubated with L-glutamate. The classical subtype has a stronger growth response to L-glutamate compared to the other two subtypes. Transcriptomic data from TCGA showed that the expression of GRIK4 (glutamate ionotropic receptor kainate type subunit 4) is the highest in the classical subtype. By comparing GRIK4 expression with patient survival in TCGA glioblastoma cases stratified by molecular subtypes, we found that high GRIK4 expression correlates with worse prognosis in the classical subtype, but not the proneural or mesenchymal patient groups. Our findings suggest that each glioblastoma subtype may differentially leverage neuromodulatory mechanisms to support their own growth. Ongoing studies are investigating the differential neuronal responses in glioblastoma subtypes using both pharmacological and genetic approaches.
CNSC-40. HARNESSING EVOLUTIONARY CONSTRAINT IDENTIFIES POTENTIAL NON-CODING DRIVERS IN BRAIN TUMORS
Authors: Roy Ananya , Pensch Raphaela , Sakthikumar Sharadha , Kozyrev Sergey V , Nordin Jessika , Mäkeläinen Suvi , Jansson Ylva , Pettersson Mats , Karlsson Elinor , Lindblad-Toh Kerstin , Forsberg-Nilsson Karin
Published: November 2023

The somatic mutational landscape of brain tumors has primarily focused on coding mutations for driver gene discovery. Non-coding mutations can drive cancer by targeting regulatory elements and be valuable biomarkers and therapeutic targets. However, their identification and functional impact have been elusive. Here, we apply evolutionary constraint (phyloP scores, a constraint metric from sequence alignment of 241 mammals) to whole genome sequencing data from three different brain tumors; pilocytic astrocytoma (PA), medulloblastoma (MB), and glioblastoma (GBM) to identify non-coding constraint mutations (NCCMs) with regulatory potential. NCCM rates (phyloP ≥ 1.2) differ significantly between these cancers, with low rates of NCCMs in PA reflecting its benign feature and high rates in MB and GBM, in support of their aggressivity and heterogeneity. Many of the NCCMs affect genes that are developmentally regulated and expressed in the brain, hence they could be potential drivers. In PA, a high NCCM frequency only affects the BRAF locus, while in MB, over 500 genes have high levels of NCCMs. Intriguingly, many of these genes are associated with different age of onset, such as NUAK1 in adult patients and HOXB1 in young patients, pointing to different molecular pathways in patient groups. NCCMs in the HOXB locus altered the expression of multiple genes of the cluster in MB cells. In GBM NCCMs with regulatory potential cluster as hotspots in PTEN, LRFN5 and MIR99AHG. We observe an enrichment of NCCMs in the regulatory regions of transcription factors including FOXA1, HOXA9 and EBF1. We conclude that since evolutionary constraint is agnostic to cell type or disease stage, it is a powerful predictor of function. Understanding changes in the non-coding cancer genomes will lead to more robust patient stratification of future treatment.
STEM-14. TARGETING HAUSP IN GLIOMA STEM CELLS INHIBITS MALIGNANT GROWTH AND OVERCOMES RADIORESISTANCE OF GLIOBLASTOMA
Authors: Huang Zhi , Wu Lian , Huang Qian , Zhai Kui , Lathia Justin , Rich Jeremy , Yu Jennifer , Bao Shideng
Published: November 2023

Glioblastoma (GBM) is the most lethal and common type of primary brain tumor highly resistant to current treatments including radiotherapy. GBM contains heterogeneous cancer cells including glioma stem cells (GSCs) that promote malignant growth and therapeutic resistance, indicating that targeting GSCs may effectively improve GBM therapy. Here, we show that HAUSP (USP7, a deubiquitinase) is preferentially expressed by GSCs in the perivascular niches in human GBMs. Disrupting HAUSP by shRNA or its inhibitor P22077 promoted GSC differentiation, impaired GSC growth, and potently inhibited GBM malignant growth, indicating that HAUSP is required for maintaining the self-renewal and tumorigenic potential of GSCs. Moreover, pharmacological inhibition of HAUSP synergized with irradiation (IR) to suppress GBM tumor growth, suggesting that targeting HAUSP may effectively overcome GSC-driven radioresistance to improve therapeutic efficacy for GBM. Our findings uncover a novel role of HAUSP in maintaining GSC phenotypes and tumorigenic potential, and thus offer a promising druggable target for developing anti-GSC therapeutics to improve GBM treatment. Furthermore, our preclinical data suggest that inhibiting HAUSP alone or in combination with IR may prolong the survival of GBM patients.
STEM-17. IMPLICATING ASTROCYTE PROGENITOR SIGNATURES FROM THE DEVELOPING HUMAN SUBVENTRICULAR ZONE IN GLIOBLASTOMA PROGRESSION AND RECURRENCE
Authors: Ramos Susana Isabel , Chang Wan Sze , Zaslavsky Elena , Tsankova Nadejda
Published: November 2023

Although astrocyte-like progenitors in the adult subventricular zone (SVZ) have been put forward as the glioblastoma (GBM) cell of origin, the mechanisms that trigger astrogenesis in the developing SVZ are poorly understood. We previously reconstructed astrocyte lineages using computational tools and identified PDGFRβ+ astrogenesis-committed radial glia (RG-A) and EGFR+ gliogenic intermediate progenitor cells (gIPCs). We have, however, yet to identify the transcription factors (TFs) that drive the differentiation of these progenitors in the pre- and postnatal SVZ. As malignant cells are known to co-opt neurodevelopmental pathways, the exploitation of TF driver vulnerabilities in malignant cells could bring novel therapeutic strategies to hinder GBM progression or recurrence. Here, we integrated single nucleus RNA- (snRNA-seq) and ATAC-sequencing (snATAC-seq) datasets from 1) surgically resected GBMs (n = 5), 2) the subventricular zone and neocortex from non-pathological adult cortices (n = 3) and 3) the corresponding germinal matrix and cortical plate of non-pathological cortices ranging from 17 to 41 gestational weeks (n = 17) and 21 to 301 postnatal days in age (n = 9). To prioritize candidate drivers of astrogenesis computationally, we correlated motif enrichment with gene expression over pseudotime in gIPC and RG-A lineages. Subsequently, we projected transcriptional signatures from non-pathological neocortices onto GBMs. Interestingly, we observed high proportions of tumor cells with preferentially enriched prenatal gIPC-like signature in EGFR amplified GBMs and with preferentially enriched postnatal RG-A-like signature in GBMs with PFGFRα or FGFR3 amplification. As tumor recurrence is associated with a mesenchymal-like switch, we were intrigued to find that RG-A-like cells exhibited a mesenchymal-like phenotype in a recurrent GBM. Currently, we are developing an in vitro assay to manipulate the expression of astrogenic drivers and force the differentiation of patient-derived, primary GBM cells into astrocytes; a strategy that we will later apply in patient-derived xenograft models.
STEM-19. POTENTIAL THERAPEUTIC EFFECTS OF NOVEL HISTONE DEACETYLASE INHIBITORS ON HUMAN-DERIVED GLIOBLASTOMA TUMORSPHERES
Authors: Choi Seonah , Kim Seo Jin , Park Junseong , Choi Ran Joo , Moon Ju Hyung , Kim Eui-Hyun , Teo Wan-Yee , Chang Jong Hee , Jeon Raok , Kang Seok-Gu
Published: November 2023

BACKGROUND

Histone deacetylase (HDAC) inhibitor is a promising anticancer drug targeting epigenetic alterations on tumor cells, however, failed to prove its feasibility on glioblastoma (GBM) in several trials. We developed new HDAC inhibitors and applied them to human-derived GBM tumorsphere(TS)s to confirm its therapeutic efficacy to overcome the current limitations. Materials and

METHODS

The expression level of HDAC in GBM versus normal brain tissue was evaluated with RNA sequencing and its knock-down effects were evaluated through western blot, WST, and luciferase assay. The most potential drugs were selected among the candidates through dose-escalation WST assays, and their capacities on HDAC were evaluated through western blot and HDAC activity/inhibition direct assay. The results of the sphere-formation assay, 3D matrix invasion assay, and transcriptome data analysis were compared between the drugs, and bioluminescence images and Kaplain-Meier survival cure were obtained through a mouse model.

RESULTS

HDAC 8 is more expressed in GBM tissue and TSs than normal ones, and the knock-down of HDAC 8 shows decreases in viability, ATP levels, and related proteins. Two potential HDAC 8 inhibitors were selected and compared with suberoylanilide hydroxamic acid (SAHA) through the experiment, which discovered that they not only reduced HDAC’s expression and its activity but also stemness and invasiveness of GBM TSs to comparable levels despite the differences in transcriptional profile changes, with meaningful survival rates in a mouse model.

CONCLUSION

We have newly developed meaningful HDAC inhibitors in the tumorsphere stage, and believe it could be a fundamental result for improving future treatment methods.
CSIG-27. FLUID SHEAR STRESS ACTIVATES A MECHANO-METASTATIC CASCADE TO PROMOTE MEDULLOBLASTOMA METASTASIS
Authors: Min Hyun-Kee , Zhao Hongyu , Huang Xi
Published: November 2023

Medulloblastoma (MB) is the most common malignant pediatric brain tumor. Dissemination of MB cells into cerebrospinal fluid (CSF) and blood initiates metastasis in the central nervous system, which significantly worsens patient prognosis. Disseminated MB cells survive the nutrient-deprived CSF environment and are subjected to fluid shear stress (FSS) by CSF flow. Whether and how FSS contributes to MB metastasis is completely unknown. We computationally simulated FSS dynamics in MB patients using MRI-informed CSF flow models. Based on CSF flow rates and force magnitudes in patients, we engineered two FSS application systems: (1) an orbital shaker system that applies FSS to large populations of cells, and (2) a microfluidic system compatible with live-cell and high-resolution imaging. By applying physiologically relevant FSS to MB cells, we discovered that FSS-treated MB cells metastasize more frequently and form larger metastatic tumors along the spinal cords of mice. Mechanistically, FSS induces actomyosin contraction, which promotes cell clustering, glucose transporter 1 (GLUT1) localization at the cell surface, and GLUT1-dependent glucose uptake. FSS elevates intracellular calcium through mechanosensitive ion channel PIEZO2, which is required for FSS-induced actomyosin contraction, cell clustering, and GLUT1 activity. Genetically perturbing PIEZO2 or pharmacologically inhibiting GLUT1 robustly suppresses MB metastasis in mice. Collectively, we discover that MB cells perceive FSS, define an FSS-activated mechano-metastatic cascade, and demonstrate that this cascade is clinically targetable to mitigate MB metastasis.
CSIG-30. FUNCTIONAL CHARACTERISATION OF A NOVEL MUTATION IN PRKCA, THE MAJOR DRIVER OF CHORDOID GLIOMAS
Authors: Bellamy Charlotte , Tovell Hannah , Dingli Florent , Liva Stephane , Loew Damarys , Stefan Eduard , Schwaighofer Selina , Newton Alexandra , Sanson Marc , Bielle Franck
Published: November 2023

Chordoid gliomas (ChG) are a rare low-grade brain tumour, believed to be derived from Tanycytes. An analysis by the team previously identified a novel mutation present in all ChGs: PRKCA p.D463H. This mutation involves a D463H amino acid substitution at the kinase domain of the Protein kinase C alpha (PKCα) and represents the hallmark of ChG. PKCα is a serine/threonine kinase, that carries out the regulation of various functions in the cell. The aim of the project is to identify novel and biologically relevant PKCα D463H signalling pathways, which will demonstrate the involvement and the role of this mutated kinase in cellular functions implicated in the development of ChGs. The D463H mutation affects a critical residue of the kinase domain of PKCα, suggesting that such change may modify substrate affinity and specificity. Following the purification of the mutated form of PKCα, we have shown it is an inactive kinase, that has a dominant negative effect over the wild type (WT) PKCα. The mutation affects the tertiary structure of the protein, resulting in a more open, unstable protein. Phosphoproteomic analysis of HEK cells overexpressing the mutant protein has shown a global loss of PKCα substrate phosphosites compared to the WT condition. By understanding these changes, integrated with our snRNAseq and bulk RNAseq data of ChGs, we hope to elucidate the mechanism by which the mutation leads to tumorigenesis. Finally, the candidates will be explored in a representative context, by exploring the PKCɑ D463H mutation in primary rat Tanycyte culture and in vivo model. These models will allow us to study the effect of the mutation on cellular processes involved in the development of this rare tumour.
RADT-01. BASELINE HIPPOCAMPAL VOLUME AS A PREDICTOR OF NEUROCOGNITIVE CHANGES AFTER WBRT OR HA-WBRT: SECONDARY ANALYSIS OF NRG ONCOLOGY CC001
Authors: Abraham Christopher , Pugh Stephanie , Brown Paul , Gondi Vinai , Bovi Joseph , Robinson Clifford , Wefel Jeffrey , Roberge David , Kundapur Vijayananda , Devisetty Kiran , Shah Sunjay , Usuki Kenneth , Baschnagel Andrew , Stea Baldassarre , Yoon Harold , Li Jing , Laack Nadia , Jindal Saurahb , Borges Monica , Kachnic Lisa
Published: November 2023

PURPOSE

Hippocampal volume (HV) is a predictor of neurocognitive function (NCF) in neurodegenerative disease. The role of patient-specific anatomic variables has not been well investigated in patients with brain metastases. This work aimed to evaluate HV at baseline and 6 months as a predictor of NCF and differential benefit from HA-WBRT for patients enrolled on CC001.

MATERIALS

HV was calculated at baseline and 6 months. HV at baseline and 6 months were correlated with baseline and 2, 4, and 6-month NCF scores (HVLT-R Total and Delayed Recall, Delayed Recognition, TMT Parts A and B, and COWA) using Pearson correlation. Correlation was defined as weak if ρ ≤0.35. A cox proportional hazards model was used to determine the impact of baseline HV on time to NCF failure.

RESULTS

Of 518 patients randomized on CC001, 277 had baseline imaging, and 135 had 6-month imaging. However, only 87 patients were analyzable at both baseline and 6-month periods. At baseline, HV was not significantly associated with NCF score for any measure (p-value range: 0.06-0.72). Additionally, there was no association between baseline HV and time to NCF failure (p = 0.16). Additionally, the impact of treatment arm allocation on HV was examined but found to be non-significant (p = 0.06). Lastly, baseline HV and NCF scores were noted to have weak correlation at 2, 4, 6, and 12 month timepoints (ρ: range, -0.17-0.15; P-value range, 0.04-0.98). At 6 months, the correlation between HV, baseline NCF change, and 6 month standardized NCF change were also noted to be weak (ρ: range, 0.05-0.16; P-value range, 0.06-0.76).

CONCLUSIONS

Radiotherapy is known to have deleterious effects on neurocognition. In neurodegenerative disease, HV and rate of HV change are known predictors for NCF. However, baseline HV is not an independent predictor of neurocognitive changes after WBRT or HA-WBRT for patients with brain metastases.
RADT-07. CLINICAL OUTCOMES OF MELANOMA BRAIN METASTASES TREATED WITH NIVOLUMAB AND IPILIMUMAB ALONE VERSUS NIVOLUMAB AND IPILIMUMAB WITH STEREOTACTIC RADIOSURGERY
Authors: Tang Joseph , Mills Matthew , Dohm Ammoren , Khushalani Nikhil , Forsyth Peter , Vogelbaum Michael A , Wuthrick Evan , Yu Hsiang-Hsuan Michael , Oliver Daniel , Liu James , Ahmed Kamran
Published: November 2023

BACKGROUND

Upfront dual checkpoint blockade has demonstrated efficacy in new melanoma brain metastases (MBM) of asymptomatic patients. Whether combination stereotactic radiosurgery (SRS) with dual checkpoint blockade improves outcomes over dual checkpoint blockade alone is unknown. We evaluated clinical outcomes of new MBM receiving nivolumab and ipilimumab, with and without SRS.

METHODS

52 patients with 171 MBM receiving nivolumab and ipilimumab for untreated MBM between 2015 and 2022 were identified at our institution. Patient and tumor characteristics including age, Karnofsky Performance Status (KPS), presence of symptoms, cancer history, MBM burden, and toleration of therapy were recorded. Outcomes measured from initiation of MBM-directed therapy included overall survival (OS), local control (LC), distant intracranial control (DIC), and intracranial control (ICC). Time-to-event analysis was conducted with the Kaplan-Meier method.

RESULTS

25 patients with 74 MBM received nivolumab and ipilimumab alone. 27 patients with 97 MBM received concurrent SRS. No differences in age (p = 0.72), KPS (p = 0.94), presence of symptoms (p = 0.87), prior MBM (p = 0.90), prior MBM-directed surgery (p = 0.77) or SRS (p = 0.65), MBM size (p = 0.36), MBM number (p = 0.36), or treatment completion (p = 0.12) were seen. Median follow-up was 22.7 months. There was a trend towards higher rates of nivolumab and ipilimumab course completion in the combination group (44% vs. 24%; p = 0.12). The combination therapy group received prior immunotherapy more often than the monotherapy group (52% vs. 8.0%; p = 0.0003). OS, DIC, and ICC were similar (p = 0.16, p = 0.32, p = 0.57, respectively) with overall 12-month OS 70.7%, DIC 56.8%, and ICC 49.4%. The combination therapy group had higher 12-month LC compared to the monotherapy group (91% vs. 64%; p = 0.001).

CONCLUSION

In our analysis, SRS with nivolumab and ipilimumab shows superior LC compared to nivolumab and ipilimumab alone despite our combination cohort being more advanced with higher rates of prior immunotherapy. Further prospective study of combination nivolumab and ipilimumab with SRS is warranted.
RADT-08. IS THERE A CORRELATION BETWEEN ANEMIA AND RADIATION NECROSIS IN BREAST CANCER PATIENTS WITH BRAIN METASTASES UNDERGOING RADIOSURGERY? A PRELIMINARY SINGLE-INSTITUTION COHORT STUDY
Authors: Wilding Hannah , De Macedo Filho Leonardo Jose Monteiro , Bhanja Debarati , Husain Rabab , Hong Jinpyo , Moeckel Camille , Mansouri Alireza
Published: November 2023

INTRODUCTION

Stereotactic radiosurgery (SRS) is a highly effective treatment for brain metastases. Radiation necrosis (RN) is a prominent dose-limiting toxicity, occurring in 5-10% of patients. Data on differences in RN incidence based on tumor molecular markers and the potential correlation with anemia have not been explored. The objective of this study was to 1) report our institutional rates of RN in patients with breast cancer brain metastases (BCBM) undergoing radiosurgery; and 2) investigate the correlation of anemia with RN rates.

METHODS

A retrospective review of patients with BCBM treated with SRS between May 2006 and October 2020 was conducted. To ensure homogeneity, only patients with oligometastatic disease (1-4 BM) and only 1 session of SRS were included. Hemoglobin (Hb) was assessed from 3 months before or 6 months post SRS, and diagnosis of anemia was made for Hb <13 g/dL in males and Hb <12 g/dL in females. Logistic regression was used to analyze correlation of anemia and RN.

RESULTS

44 patients were included (82 total lesions treated by SRS, median 2). Seventy-seven lesions were treated with SRS to a median dose of 20 Gy (15-24 Gy). Five lesions were treated with fractionated SRS (30Gy, 3-5 fractions). Five patients (11.4%) developed RN based on imaging; two went on to biopsy with one having pathological confirmation of RN. Anemia was identified in twenty-eight (63.7%) patients; 1 was treated with iron supplementation. Although anemia was not significantly associated with RN, patients with anemia did have significantly lower OS than those without (p = 0.04).

CONCLUSION

Our institutional data suggest similar RN rates in BCBM patients as the literature. Our sample size was too small to investigate correlation between anemia and RN, though survival may be impacted. Larger, multi-institutional studies are underway to further study this possibility.
RADT-27. BONE MARROW SUPPRESSION AFTER REIRRADIATION THERAPY WITH PROTON VERSUS PHOTON THERAPY FOR RECURRENT GLIOMA
Authors: Subramaniam Varun , Zhou Alexander , Rios Carlos Ortega , Hadjipanayis Constantinos , Lazarev Stanislav , Press Robert
Published: November 2023

INTRODUCTION

High grade radiation-induced lymphopenia has been implicated to worse prognostic outcomes and overall survival in numerous malignancies. Understanding factors which influence lymphopenia can help optimize radiation delivery and overall patient care. Proton therapy (PRT), due to its distinct dose fall-off, spares tissues and organ-contained blood pools from excess radiation compared to conventional photon radiation (XRT) and may thereby reduce hematologic toxicity.

METHODS

Patients with confirmed glioma diagnosis who underwent reirradiation with either PRT or XRT were retrospectively analyzed. Complete blood counts (CBCs) within one month of reirradiation start, and CBCs within one month of reirradiation completion were reviewed. Values of interest included total white blood cell (WBC), absolute neutrophil count (ANC), and absolute lymphocyte count (ALC). Dosimetric data was collected to assess whole brain mean dose (WBMD), and volume of brain tissue receiving 5-50 Gy (V5-V50).

RESULTS

16 patients receiving either PRT (n = 8) or XRT (n = 8) were included. Treatment doses ranged from 35-59.4 Gy. Across all patients there was a decrease in WBC, ANC, and ALC after reirradiation in both PRT and XRT (p < 0.05). Compared to reirradiation with XRT, patients who underwent PRT had significantly lesser reductions in WBC (PRT: 8.60% decrease, XRT: 22.58% decrease; p < 0.05). PRT reirradiation also resulted in lesser ANC and ALC reductions, though did not reach statistical significance. On dosimetric comparison of XRT and PRT plans, PRT demonstrated significant reductions in V5, V10, V20, and V30 (p < 0.05). V5 through V40 and WBMD were significantly correlated with decreased WBC, ANC, and ALC (p < 0.01).

CONCLUSION

Preliminary results show PRT reirradiation leads to decreased WBMD and volumes of brain tissues receiving 5 to 30 Gy. Given that these parameters are associated with greater reductions in lymphocytic counts, PRT reirradiation may confer reduced hematologic toxicity in patients seeking adjuvant radiation therapy.
CTIM-05. RESULTS OF SAFETY LEAD IN OF PHASE II TRIAL OF COMBINATION OLAPARIB, TEMOZOLOMIDE, AND PEMBROLIZUMAB FOR PATIENTS WITH IDH-MUTANT GLIOMA
Authors: Fortunato John , Newton Adam , Gonzalez Ashley , Gavrilovic Igor , Miller Alexandra , Grommes Christian , Lin Andrew , Pentsova Elena , Mellinghoff Ingo , Kaley Thomas , Schaff Lauren
Published: November 2023

BACKGROUND

Recurrent gliomas are universally fatal with few adequate treatment options. IDH-mutant gliomas may be susceptible to PARP inhibition, thus combination therapy using alkylating agents and checkpoint inhibition could be synergistic.

METHODS

This is an open label, phase II study of olaparib, temozolomide, and pembrolizumab for patients with recurrent IDH-mutant glioma, grade 2 or 3, with measurable enhancing disease per RANO. Patients received pembrolizumab 200mg IV on day 1 of each 21-day cycle. Oral olaparib 200mg twice daily and temozolomide 50mg/m2 daily were given days 1-7 of cycles 3-11. Here, we report the results of our safety lead in, consisting of the first 6 patients to complete cycle 3.

RESULTS

A total of seven patients were enrolled to the safety lead-in: 2 women; 5 patients with astrocytoma, 2 oligodendroglioma. Patients had a median age of 45 (range 29-63) and median KPS 90 (range 80-100). Median number of recurrences was 3.5 (range 1-5). All had received prior alkylating therapy and all but 1 patient had received prior RT. No patients were taking steroids at the time of enrollment. Six patients completed the dose-limiting toxicity (DLT) period without any DLTs. One patient experienced clinical progression on pembrolizumab monotherapy prior to the start of combination therapy and was thus replaced. No grade 3 or 4 toxicities were seen through the DLT period. The most common clinical toxicities at least possibly related to treatment were grade 1 and 2 fatigue (n = 4), nausea (n = 3) and constipation (n = 2). Hematological toxicities include grade 1 anemia (n = 2) and decreased platelet count (n = 1).

CONCLUSIONS

The combination of olaparib, temozolomide, and pembrolizumab was well tolerated in this cohort. Following completion of the safety lead-in, the trial was redesigned to minimize the length of pembrolizumab monotherapy and introduce combination therapy in cycle 1. Enrollment is ongoing. NCT05188508.
CTIM-20. SYSTEMIC IMMUNE CORRELATES ASSOCIATED WITH LONG-TERM SURVIVAL AFTER THERAPEUTIC ADENOVIRUS (DNX2401) PLUS INTERFERON GAMMA FOR RECURRENT GLIOBLASTOMA EFFECT TRIAL (TARGET): A RANDOMIZED PHASE 1 TRIAL
Authors: Ene Chibawanye , Singh Sanjay , Phillips Lynette , Venkataraman Raja , Puduvalli Vinay , Singh Deep , Tram Nam , Long James , Brady Martin , Raghavan Raghu , Tufaro Frank , Ewald Brett , Anand P J , Bradley Elder J , Fink Karen , Alfred Yung W K , Penas-Prado Marta , Navin Nick , Larman Benjamin , Gomez-Manzano Candelaria , Fueyo-Margareto Juan , Peterkin Joanna , Lang Frederick
Published: November 2023

Anti-tumor immune response following oncolytic virus treatment of glioblastoma may be enhanced by immune activating therapies. Here, in this Phase Ib, multicenter, randomized, open-label study we evaluated the combination of intra-tumoral delivery of oncolytic virus DNX-2401 with subcutaneous interferon gamma (IFN-γ) a T-helper 1 response activator in 37 patients with recurrent glioblastoma. In part 1, 27 patients were randomized 2:1 into DNX-2401 with IFN-γ and DNX-2401 alone with intra-tumoral DNX-2401 administered via a standard biopsy needle. In part 2, 10 patients received intra-tumoral DNX-2401 via an FDA-approved Alcyone MEMS Cannula designed to prevent backflow at high infusion flowrates. DNX-2401 was well tolerated but the addition of IFN- γ was not well tolerated. The primary efficacy endpoint, objective clinical response, was not met. The secondary endpoint of 12-month overall survival for DNX-2401 with IFN-γ, DNX-2401 alone and DNX-2401 via Cannula were 33%, 22%, 0% respectively. The 18-month OS for DNX-2401 with IFN-γ, DNX-2401 alone and DNX-2401 via Cannula were 25%, 9%, 0% respectively. The DNX-2401 with IFN- γ cohort had the most long-term survivors (44.2, 23.7, 20.6 and 20.1 months). Systemic antibody and immune cell profiling following DNX-2401 treatment showed that long term survivors had significantly higher anti-adenovirus specific antibody reactivity and a higher activated CD8+ effector memory T-cell sub-population at 2 months post-treatment relative to baseline. This systemic immune response did not occur in short term survivors following DNX-2401 treatment. Overall, these data suggest that an early and robust systemic adaptive immune response could be used as a biomarker for long term survival following DNX-2401 treatment of recurrent glioblastoma independent of other salvage treatments administered following disease progression during the trial. (Clinical Trial.gov registration: NCT02197169).
CTIM-26. IMPACT ON SURVIVAL OF INTERFERON-ALPHA DELIVERY IN GLIOBLASTOMA WITH UNMETHYLATED MGMT BY IMMUNO-GENE THERAPY WITH TEMFERON
Authors: Finocchiaro Gaetano , Cuccarini Valeria , Gentner Bernhard , Capotondo Alessia , Farina Francesca , Naldini Matteo Maria , Barcella Matteo , Anghileri Elena , Bruzzone Maria Grazia , Carrabba Matteo , D'alessandris Quintino Giorgio , Meco Francesco Di , Ferla Valeria , Franzin Alberto , Ferroli Paolo , Gagliardi Filippo , Legnani Federico , Mazzoleni Stefania , Mortini Pietro , Olivi Alessandro , Pallini Roberto , Patanè Monica , Paterra Rosina , Pollo Bianca , Saini Marco , Snider Silvia , Mullen Karen , Naldini Luigi , Russo Carlo , Ciceri Fabio , Eoli Marica
Published: November 2023

Temferon is an ex vivo gene therapy consisting of autologous Hematopoietic Stem Progenitor Cells (HSPCs) genetically modified with a lentiviral vector to deliver IFN-α2 within the tumor microenvironment by Tie-2 expressing macrophages. TEM-GBM is an open-label, Phase I / IIa dose-escalation study evaluating safety and efficacy of Temferon in up to 27 newly diagnosed GBM patients with unmethylated MGMT (uMGMT). As of 30th April 2023, 19 GBM patients in 4 cohorts received incremental doses of Temferon and four are still alive after a median follow-up of 15 months. Six of the treated patients underwent a second surgical intervention at a median of 11 months after 1st surgery. For all patients, median overall survival (OS) and median progression free survival following first surgery reach 15 months and 9.8 months from diagnosis, respectively. The interim survival rate at 2 years in Temferon-treated patients is 28% (5 of 18 patients; 1 patient excluded as follow-up is below 1 year). OS and survival rate at 2 years of uMGMT patients treated as per the current standard of care (SOC) is 12.7 months and 14,8% respectively. One out of the surviving patients is alive 3 years after first surgery without second line therapy added up to 2 years. The other four patients with 2 year follow-up were treated with Gamma-Knife followed by bevacizumab (n = 1), regorafenib followed by bevacizumab (n = 1) and bevacizumab only (n = 2). Bevacizumab administration started 12 months after 1st surgery for one patient and 19 months for the other 2 patients at 5 mg/kg. These data corroborate the initial evidence on safety and tolerability of Temferon. They also suggest that Temferon has potential to counteract disease progression in patients affected by uMGMT GBM.
CTIM-37. A PILOT STUDY OF AXICABTAGENE CILOLEUCEL (AXI-CEL) FOR THE TREATMENT OF RELAPSED/REFRACTORY PRIMARY AND SECONDARY CENTRAL NERVOUS SYSTEM LYMPHOMA (PCNSL AND SCNSL)
Authors: Nayak Lakshmi , Falvey Caroline , Bouvier Riemke , Chukwueke Ugonma , Hogan Sarah , Kendricken Elizabeth , Meehan Christopher , Redd Robert , Fisher Jennifer , Torres Alexandra , Jones Julia , Lee Eudocia , Kim Austin , Castro Luis Nicolas Gonzalez , McFaline-Figueroa Jose Ricardo , Aquilanti Elisa , Youssef Gilbert , Arrillaga-Romany Isabel , Murakami Mark , Sholl Lynette , Meredith David , Huang Raymond Y , Ramsdell Linda , Gerdemann Ulrike , Keskula Paula , Kaminski Jim , Albanese Alexandre , Bi Wenya Linda , Arnaout Omar , Reardon David , Wen Patrick , Poddar Soumya , Mao Daqin , Mattie Mike , Davis Madison , Filosto Simone , Kean Leslie , Armand Philippe , Jacobson Caron
Published: November 2023

BACKGROUND

Optimal therapy for patients with relapsed/refractory (R/R) CNSL is not defined, and their prognosis is poor. Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy axicabtagene ciloleucel(axi-cel) has demonstrated superior efficacy over standard of care in R/R systemic diffuse large B-cell lymphoma and could be an effective regimen for R/R CNSL.

METHODS

This is a pilot study of axi-cel in patients with R/R CNSL. Only corticosteroids were allowed for bridging. Patients underwent lymphodepletion with fludarabine and cyclophosphamide followed by standard axi-cel dosing of 2x106 cells/kg infusion. An Ommaya reservoir was placed prior to infusion. The first 6 patients enrolled were observed for treatment-limiting toxicities(TLTs). The study enrolled a total of 17 patients. Primary endpoint was safety, measured by rate of TLTs and grade 3+ adverse events(AEs). Secondary endpoints included objective response rate(ORR), complete response(CR) rate, duration of response(DOR), progression-free survival(PFS) and overall survival(OS). Exploratory analyses included paired peripheral blood and CSF analyses for axi-cel pharmacokinetics, cytokine levels, flow cytometry, single-cell RNA-Seq and circulating tumor-DNA.

RESULTS

We report the results of all 17 patients(13 PCNSL, 4 SCNSL) enrolled. Median age was 64 years (34-80), 8/17 were women. As of 6/2023, 14 treated patients had >1 month follow-up, with 86%(12/14) ORR and 64%(9/14) CR. Six patients progressed. No TLTs were observed; 15/16(94%) patients developed cytokine release syndrome/CRS (grade 3+, 0%), 8/16(50%) developed immune effector cell-associated neurologic syndrome/ICANS, (grade 3+, 5/16(31%)). PFS, OS, DOR and correlatives will be reported at the meeting. Daily examination of CAR T-cells in blood and CSF by scRNA-Seq revealed evolution of a prominent Type I interferon (IFN) transcriptomic signature of CAR-Ts in the CSF.

CONCLUSION

Axi-cel is safe and well-tolerated in CNSL patients with promising efficacy and no apparent additional risk of adverse neurologic events including ICANS. IFN pathway may play a major role in CAR-T efficacy in CNSL.