bluuebunny/crossref_metadata_2025 huggingface dataset:
DIPG-34. IDENTIFICATION OF CAR-T CELL ENHANCING COMPOUNDS USING HIGH THROUGHPUT SCREENING
Authors: Jones Amber B , Meehl Michaela , DeVries Rebekah , Shelat Anang , Krenciute Giedre
Published: June 2024

BACKGROUND

The infiltrative growth patterns and restrictiveness of the blood brain barrier greatly limit therapeutic options for children diagnosed with diffuse intrinsic pontine gliomas (DIPGs). However, clinical trials using chimeric antigen receptor (CAR)-T cells have shown promise in DIPG patients. Despite some success, the biological limitations plaguing CAR-T cells hinder their overall efficacy. We propose that leveraging chemical compounds in tandem with CAR-T cells may provide an increased therapeutic benefit against this lethal brain tumor. Our study is aimed at using high throughput screening of >2,000 FDA approved and investigational compounds to identify candidates that enhance CAR-T cell mediated cytotoxicity of DIPGs.

METHODS

In an initial limited screen (32 compounds) used for optimization, compounds were serially diluted using the Echo 650 acoustic liquid handler. Subsequent co-culture conditions of renilla luciferase transduced DIPG007 tumor cells and clinically relevant firefly luciferase transduced CAR-T cells were plated at a 2:1 effector: target (E: T) ratio. In comparison to DMSO control, drug induced changes on cell viability were measured using cell-specific luciferase activity at 24 and 72 hours.

RESULTS

The limited screen revealed the BET bromodomain inhibitor, GSK-046, as an initial target based on its ability to increase CAR-T cell viability after 72 hours. Preliminary validation of these findings supports this CAR-T enhancing role of GSK-046 via MTS assays. We also identified nonlethal concentrations of GSK-046 for DIPG007 cells that could be further tested in combination with CAR-T cells to determine therapeutic synergy.

CONCLUSIONS

Our initial findings warrant further investigation into the combinatorial benefit of GSK-046 and CAR-T cells against DIPGs. Currently, we are optimizing and expanding our drug screen to identify additional compounds that may complement CAR-T cell therapy. Furthermore, we intend to validate the cytotoxic benefit of our prioritized combinations in additional in vitro and in vivo settings.
DIPG-45. TARGETING HYPERACETYLATION IN PEDIATRIC DIFFUSE MIDLINE GLIOMAS USING ONCOLYTIC ADENOVIRUSES
Authors: Parthasarathy Akhila , Garcia-Moure Marc , He Jiasen , Shin Dong Ho , Gillard Andrew G , Lopez-Rivas Andres , Hampton Lethan A , Fan Xuejun , Jiang Hong , Lang Frederick F , Alonso Marta M , Gomez-Manzano Candelaria , Fueyo Juan
Published: June 2024

BACKGROUND

H3K27-altered pediatric diffuse midline glioma (DMG) is a highly aggressive type of brain tumor with a 5-year survival rate of less than 2%. Conventional treatments are restricted to palliative radiation therapy. Therefore, effective treatments are urgently needed. Results from a recent phase I clinical trial for Diffuse Intrinsic Pontine Glioma showed that intratumoral administration of Delta-24-RGD oncolytic adenovirus in combination with radiation improves survival without unwanted toxicity. Based on the rationale that, during infection, the early viral protein E1A binds P300, we hypothesize that combining oncolytic adenoviruses with p300 inhibitors will induce a robust modification of the post-translational landscape of DMGs and increase the anti-cancer effect of the oncolytic virus.

METHODS

Studies on Delta-24-RGD infectivity and replication were performed in a panel of clinically significant DMG cells. Modification of the acetylation levels of acid-extracted histones after Delta-24-RGD was analyzed using Western blot. Cell Titer Blue was utilized to measure cell viability, and ZIP-synergy scores were calculated using SynergyFinder.

RESULTS

We observed a time-dependent reduction in H3K27ac in human DMG cells following Delta-24-RGD infection with an 89% reduction in H3K27ac at 48h post-infection. Delta-24-RGD treatment of DMG cells resulted in optimum viral infectivity and replication. Combining Delta-24-RGD with the p300 inhibitor C646 resulted in enhanced cell death in vitro. Using a panel of oncolytic viruses that induce differential enzymatic and binding functions of P300, we showed that Delta-24-RGD mediated alteration of P300 activity is required for hypoacetylation in DMGs. We characterized the in vivo dynamics of K27M-H3.1 and K27M-H3.3 DMG-derived tumors in the brain stem of syngeneic animal models. In vivo experiments are in progress to examine the combinatorial anti-glioma effect of Delta-24-RGD and P300 inhibitors.

CONCLUSION

Collectively, our studies provide a strong mechanistic rationale for combining oncolytic adenoviruses and p300 inhibitors and should propel the eventual clinical testing of this approach in DMG patients.
DIPG-49. SPATIAL TRANSCRIPTOMIC SEQUENCING OF A DIPG PATIENT TUMOUR RESOURCE
Authors: Kordowski Anja , Mulay Onkar , Harris Lachlan , Nguyen Quan H , Day Bryan W
Published: June 2024

BACKGROUND

Diffuse Intrinsic Pontine Glioma (DIPG), the most common subtype of Diffuse Midline Glioma (DMG), is a brainstem high-grade glioma arising in young children and always proves fatal. Major challenges include the disease’s intratumoural genetic and cellular heterogeneity as well as its diffusely invasive phenotype. Research of the last few years has highlighted that interactions between cancer cells, the nervous system and immune cells crucially contribute to tumour cell invasion and disease malignancy. Hence, a better understanding of cancer-promoting interactions is a key requirement to elucidate novel strategies for the treatment of this devastating disease.

METHOD

We performed spatial transcriptomic sequencing on 10 sequential tumour-infiltrated DIPG patient brainstem regions, using the 10x Genomics Visium platform.

RESULTS

Spatially-informed analysis and cell type clustering overall highlighted the molecular intratumoural heterogeneity present in the disease. We assessed cell cluster interactions as well as receptor-ligand (RL) pairing, illustrating communication between neuronal, immune cell and tumour clusters. We further determined respective RL pairs involved in such. To address the question whether invasive edges genetically differ from the tumour core, we evaluated genes that are significantly correlated with distal brainstem regions compared to tumour proximal sites. Results revealed gene signatures that are highly associated with neuronal signalling and communication, validating previous findings emphasising the importance of neuron-to-glioma interactions driving DIPG disease progression.

CONCLUSION

DIPG is a lethal paediatric brainstem glioma for which more durable therapeutic modalities remain to be found. In-depth analysis of this disease is often hampered due to the lack of patient tissue suitable for laboratory studies. Our patient autopsy specimen, spanning the entire tumour-infiltrated brainstem provided a platform to study this aggressive disease in a spatio-temporal manner. This analysis elucidates how DIPG is driven by the tumour microenvironment, including associated receptor-ligand interactions. This has the potential to ultimately discover new treatment targets.
DIPG-50. TARGETING VULNERABILITIES IN PAEDIATRIC DIFFUSE MIDLINE GLIOMAS: LEVERAGING PLK1 INHIBITION TO EXPLOIT RAS/PI3K PATHWAY DEPENDENCY
Authors: Hayden Elisha , Dolman Emmy M , Upton Dannielle H , Franshaw Laura , Liu Jie , Nguyen Hieu , Tsoli Maria , Guo Xinyi , Mayoh Chelsea , Rayner Benjamin S , Ziegler David S
Published: June 2024

BACKGROUND

Diffuse Midline Gliomas (DMGs), characterised by prevalent H3K27M mutations, exhibit epigenetic modifications that drive a proliferative state resistant to conventional therapies. The interplay of the cell cycle with PI3K and RAS/MYC growth signalling pathways, pivotal in the context of the H3K27M mutation, is yet to be fully understood. The aim of this study was to assess the efficacy of the inhibition of Polo-like kinase 1 (PLK1), a critical regulator of mitosis and cell cycle progression, identify mechanisms of action, and to develop effective combination strategies against DMG.

METHODS AND RESULTS

PLK1 inhibition demonstrated significant anti-tumour activities both in vitro and within aggressive in vivo orthotopic DMG models, notably doubling the median survival of mice bearing tumours. High-throughput RNA-seq analysis of DMG samples particularly sensitive to PLK1 inhibition, revealed a distinct pattern of negative enrichment in ribosomal genes, indicating a marked reduction in ribosomal function-associated gene expression. This alteration suggests a potential for innovative drug combination strategies targeting the PI3K/mTOR and RAS/MYC pathways, crucial for ribosomal and RNA processing. Subsequently, our in vitro drug sensitivity assays demonstrated that PLK1 inhibition in combination with PI3K/mTOR and MEK inhibitors, exhibit strong drug synergies, evidenced by high Bliss synergy scores.

CONCLUSIONS

Our findings underscore the efficacy of simultaneous targeting of PI3K/mTOR and RAS/MYC pathways with PLK1 inhibition as an attractive strategy to mitigate DMG tumorigenesis. Furthermore this research not only sheds light on the crucial interplay between cell cycle and signalling pathways in DMG but also facilitates novel intervention strategies for a range of other paediatric CNS malignancies with similar characteristic molecular drivers.
DIPG-69. IN-VITRO DETERMINATION OF 5-AMINOLEVULINIC-ACID-TREATMENT EFFICACY IN PATIENT-DERIVED DIPG MODELS
Authors: Stano Martin , Kritzer Bettina , Hierlemann Andreas , Nazarian Javad , Modena Mario Matteo
Published: June 2024

BACKGROUND

Diffuse Intrinsic Pontine Glioma (DIPG) presents a significant clinical challenge due to its inoperable nature and poor response to current treatments. Sonodynamic Therapy (SDT) is a non-invasive therapy that combines low-intensity ultrasound stimulation with a sonosensitizing agent. 5-Aminolevulinic Acid (5-ALA) as a sonosensitizer has yielded positive outcomes in in-vivo glioblastoma models, and a clinical trial (NCT05123534) for DIPG patients is currently ongoing. 5-ALA is a precursor of Protoporphyrin IX (PpIX), which preferentially accumulates in cancer cells and generates cytotoxic reactive oxygen species upon activation by ultrasound or light. Our work is aimed at investigating the accumulation of PpIX in in-vitro DIPG patient-derived cell models to predict the efficacy of 5-ALA SDT treatment.

METHODS

Patient derived DIPG cell lines (H3K27M, P53 mutant and wild type) were used to create three-dimensional spheroids. The spheroids were dosed with 5-ALA for 4 hours, and PpIX accumulation was quantified by measuring its fluorescence intensity within the cells. The spheroids were then exposed to controlled light stimulation as an in-vitro proxy for SDT.

RESULTS

We confirmed the uptake of 5-ALA and subsequent PpIX accumulation in all patient-derived DIPG spheroids. Light exposure of 5-ALA treated DIPG spheroids resulted in reduced viability of the tumor models, while 5-ALA itself did not show cytotoxic effects. The extent of PpIX accumulation and cytotoxicity upon PpIX light activation varied among DIPG models with higher sensitivity of p53 wild type cells. Further studies incorporating a larger number of DMG cells with p53 alterations are underway.

CONCLUSIONS

These findings indicate that SDT using 5-ALA as sonosensitizer may offer clinical benefits for treatment of DIPG, however treatment efficacy could vary considerably between patients. In vitro evaluation of PpIX accumulation and sensitivity to activation could potentially provide a means to stratify patients and to identify those most likely to benefit from 5-ALA-mediated SDT.
DIPG-89. ENHANCEMENT OF BLOOD-BRAIN BARRIER PENETRATION AND TUMOR TARGETED DRUG DELIVERY FOR DMG USING A P-SELECTIN TARGETED NANOMEDICINE APPROACH
Authors: Li Bryan K , Vaynshteyn Jake , Tylawsky Daniel , Vogt Kristen , Raziuddin Raashed , Ge Yi , Heller Daniel A , Becher Oren , Raju G Praveen
Published: June 2024

The blood-brain barrier (BBB) is one of the greatest barriers for the effective treatment of brain tumors, including H3K27-altered diffuse midline glioma (DMG), a near universally fatal childhood brain cancer. The BBB typically requires drugs to be given at maximally tolerated doses that are limited by systemic toxicities, particularly in settings of combination therapy. We have developed a clinically compatible fucoidan nanoparticle (Fi-NP) that homes to P-selectin on tumor vasculature after low-dose radiation (RT) to breach the BBB through an active caveolin-1-dependent mechanism and deliver several classes of targeted therapies. In non-CNS cancer xenograft models and a transgenic mouse model of SHH-driven medulloblastoma with an intact BBB, this approach improved survival while eliminating on-target systemic toxicities. We have now applied this approach to both brainstem and non-brainstem RCAS-TVA mouse models of DMG with an intact BBB. Specifically, we have found that DMG tumor vasculature expresses P-selectin, and that a single low-dose 2 Gy fraction of ionizing radiation further enhances it in a time-dependent manner up to 24 hours post-treatment. Importantly, we have also found that this P-selectin targeted drug delivery approach facilitates DMG tumor localization of Fi-NP encapsulated EZH2 inhibitor tazemetostat (EPZ-6438) as well as larger macromolecules including the PROTAC BET degrader dBET6, two promising targeted therapies for DMG limited by extremely poor BBB-penetration, while sparing drug delivery to non-tumor healthy brain regions. Work to measure PK, biodistribution, survival benefit, and drug target inhibition is ongoing. Our findings will provide the foundation for this P-selectin targeted Fi-NP approach to be evaluated in clinical trials for children with this lethal cancer.
TRLS-14. PNOC022 REPORT: A COMBINATION THERAPY TRIAL USING AN ADAPTIVE PLATFORM DESIGN FOR PATIENTS WITH DIFFUSE MIDLINE GLIOMA AT INITIAL DIAGNOSIS, POST-RADIATION THERAPY, OR PROGRESSION
Authors: Kline Cassie , Franson Andrea , Banerjee Anuradha , Reddy Alyssa T , Raber Shannon , Hoffman Carly , Minturn Jane , van der Lugt Jasper , de Vos-Kerkhof Evelien , van Vuurden Dannis , Gerber Nicolas , Stucklin Ana S Guerreiro , Kilburn Lindsay , Elster Jennifer , Whipple Nicholas , Cohen Kenneth , Oren Michal Yalon , Gardner Sharon , Cluster Andrew , Chi Susan , Landi Daniel , McCowage Geoffrey , Vo Josh , Resnick Adam , Phillips Joanna , Bhatia Aashim , George Elizabeth , Vossough Arastoo , Nabavizadeh Ali , Braunstein Steve , Gupta Nalin , Prados Michael , Waszak Sebastian , Long-Boyle Janel , Molinaro Annette , Dun Matthew , Koschmann Carl , Nazarian Javad , Mueller Sabine
Published: June 2024

BACKGROUND

Children with diffuse midline glioma (DMG) face dismal prognoses. PNOC DMG-ACT (DMG-Adaptive Combination Trial, PNOC022) is an open-label, international trial investigating the efficacy of combination therapies for patients with DMG. We present an early report on Cohorts 1-3, treated with ONC201, an orally available ClpP agonist, and paxalisib, a dual PI3K-mTOR inhibitor.

METHODS

Patients aged 2-39 years enrolled pre-radiation (Cohort 1), 4-14 weeks post-radiation (Cohort 2), or at progression (Cohort 3). Patients were randomized to receive ONC201 or paxalisib prior to surgery when biopsy was indicated and/or in combination with radiation when radiation was indicated. Those not planned for biopsy were required to submit archival tissue. All received maintenance therapy with weekly ONC201 (weight based adult equivalent of 625 mg) and daily paxalisib (27 mg/m2). Plasma and CSF samples for pharmacokinetics (PK) and biologic correlates were collected.

RESULTS

Between November 2021 and September 2023, 132 patients met critera for study therapy (Cohort 1=33; Cohort 2=69; Cohort 3=30; median age 9 years [range 2-37], n=73 female [55%]; n=86 pontine [65%]). Median overall survival (OS) from diagnosis is 13.2 months in Cohort 1 (lower 95% CI 11.1) and 15.8 months in Cohort 2 (lower 95% CI 13.9). Median OS from progression is 8.8 months in Cohort 3 (lower 95% CI 8.6). Most common non-hematologic grade 3 and above treatment-related adverse events (TRAE) were maculopapular rash (n=12); mucositis (n=8); colitis and hyperglycemia (n=7). Most common serious TRAEs were colitis (n=7) and hyperglycemia (n=6). We have collected 169 CSF samples and >600 plasma samples for ctDNA. Cohort 2 PK from CSF and plasma and CSF metabolomics and somatic mutation landscapes are being finalized.

CONCLUSIONS

We will present somatic mutation profiles, PK analysis, ctDNA, and metabolic signatures from the CSF in association with toxicity, survival, and tumor response via central imaging review.
ETMR-02. CNS EMBRYONAL TUMOR WITH BRD4–LEUTX FUSION POTENTIAL NEW MOLECULAR SUBTYPE OF EMBRYONAL TUMORS IN THE FUTURE WHO CLASSIFICATION OF TUMORS OF THE CENTRAL NERVOUS SYSTEM
Authors: Mobarak Nahla Aly , Banyan Ayman Al , Alyamnai Basma , Shakweer Wafa Al , Al-Dandan Sadeq , Alharbi Musa
Published: June 2024

INTRODUCTION

Central Nervous System (CNS) embryonal tumors previously called Primitive neuroectodermal tumors of the CNS (CNS-PNETs) are highly malignant tumors that predominantly affect Yonge children. CNS World Health Organization (WHO) 2021classification includes new embryonal tumor subtypes: CNS neuroblastoma, FOXR2-activated, CNS tumor with BCOR internal tandem duplication (ITD), and cribriform neuroepithelial tumor CRINET.CNS-embryonal tumors which cannot be classified into a specific subgroup, considered as ‘‘CNS embryonal tumors, NOS.’’

METHOD

We report a 2-year girl previously healthy presented with 2 weeks HX of vomiting, progressive lower limb weakness, and nystagmus. Radiological diagnosis was suggestive of metastatic ATRT with Brain and spine MRI showed a large left interventricular tumor (10.2 x 7.7 x 7.6 cm) centered in the posterior horn of the left lateral ventricle with extensive intracranial and spinal leptomeningeal CSF seeding metastasis she had Partial tumor resection LT-sided external ventricular drain EVD Insertion The tumor showed very aggressive behavior with rapid tumor recurrence/progression post-surgical resection the patient was treated with Palliative chemotherapy due to clinical and neurological deterioration the patient and died 2 months after diagnosis.

RESULT

Pathological examination showed Embryonal tumor (WHO Grade 4) with Medulloblastoma-like cells Immunohistochemistry: Synaptophysin: Positive Beta-catenin, P53: Negative and INI-1: Retained. NGS molecular testing was positive for BRD4–LEUTX fusion. Tumor DNA- -methylation profiling (DKFZ CNS v12.5) confirmed the diagnosis “CNS embryonal tumor with BRD4–LEUTX fusion” This rare very aggressive/uncurable tumor may show pathological features similarities with Medulloblastoma. Also, BRD4–LEUTX fusion was reported in pediatric epithelioid malignant peripheral nerve sheath tumor and an alveolar rhabdomyosarcoma

CONCLUSION

CNS tumor with BRD4– LEUTX fusion” A rare tumor has been described in the literatures in infant and young children and may be integrated in the CNS WHO classification as a new highly aggressive subgroup of CNS embryonal tumor.
ETMR-29. PRIMARY CNS SARCOMAS IN CHILDREN AND ADOLESCENTS: EXPERIENCE OF AN INSTITUTION
Authors: de Oliveira Milena Reis Santos , Rodrigues Jessica Benigno , Almeida Daniela Barbosa , Cavalheiro Sergio , Dastoli Patricia , Devanir Marcos , Silva Frederico , Seixas Maria Teresa , Toledo Silvia , Lima Fernanda Teresa , Cappellano Andrea Maria , Silva Nasjla Saba
Published: June 2024

BACKGROUND

Soft tissue sarcomas represent 6% of childhood cancers, less than 0.2% of CNS tumors are primary intracranial sarcomas. Their origin is pluripotential primitive mesenchymal cells.

OBJECTIVE

to evaluate clinical and genetic characteristics and report the experience of a rare CNS tumor.

METHODS

review of CNS tumors database at IOP/GRAACC/UNIFESP for the period 2008-2024, searching for all types of sarcomas that involved the CNS.

RESULTS

case series included 7 male, 2 female patients; average age at diagnosis 11.3 years. Supratentorial was the most common site of occurrence (66.6%), posterior fossa and intramedulary (2 and 1 cases, respectively) were found. One PF sarcoma presented as a second neoplasm after 2 years finished treatment for medulloblastoma, the other was diagnosed just after metilation. The presenting symptoms varied with tumor location, specially hemiparesis, seizure and headache. Gross total resection was achieved in 7 cases (77.7%), 1 after second look surgery. Histology and immunohistochemistry studies revealed: spinocellular sarcoma, fusocellular and myxoid sarcoma, gliosarcoma, meningeal sarcoma, Ewing sarcoma, condrosarcoma and synovial sarcoma. Work-up excluded other primary tumor origin outside CNS. Analyses for genetic characteristics were performed by Next Generation Sequencing in 6 patients (66.6%) and the following alterations were found: NRAS, TP53, JAK3, NF2, C11orf95-RELA fusion, PDGFRA. Some of these, by now, with no significant meaning for the disease. All patients underwent multimodal treatment. Chemotherapy involved mainly ICE Protocol (55.5%), but also Head Start Protocol and Ewing Sarcoma Protocol. Follow-up ranged from 13 months to 12 years, 90% of patients are alive, 2 (28.5%) dealing with endocrinal issues after focal radiotherapy. The mean overall survival was 61.4 months.

CONCLUSION

CNS primary sarcomas were mostly observed in the supratentorial region and in older children, with male predilection. Multimodal treatment seems to benefit patients’ outcomes. More patients and longer follow-up periods are needed to further elucidate the biological features of these tumors.
EPEN-07. USP7 IS AN INTERACTION PARTNER OF EZHIP AND POTENTIAL DRUGGABLE TARGET IN PFA EPENDYMOMAS
Authors: Jenseit Anne , Camgöz Aylin , Mauermann Monika , Mack Norman , Schwalm Benjamin , Mohr Jacqueline , Wittenburg Sophie , Steinebach Christian , Gütschow Michael , Peterziel Heike , Friedenauer Aileen , Jaunecker Carola , Lötsch-Gojo Daniela , Oehme Ina , Pfister Stefan M , Kool Marcel
Published: June 2024

BACKGROUND

Ependymomas (EPN) arise in the supratentorial brain (ST-EPN), posterior fossa (PF-EPN), or the spinal cord (SP-EPN), in children and adults. Among the three molecular PF-EPN groups, PFAs are characterized by young median age at diagnosis, a balanced genome and poor outcome. Recently, enhancer of zeste inhibiting protein (EZHIP) has been identified as potential driver of PFAs. By inhibiting EZH2, EZHIP prevents the distribution of the epigenetic repressor mark H3K27me3. Without known enzymatic functions though, EZHIP isn´t the urgently needed drug target. We therefore focused on essential and potentially druggable interaction partners.

METHODS

We investigated protein-protein interactions using co-immunofluorescence, co- immunoprecipitation and proximity-based assays. We utilized CRIPSR/Cas9 and shRNAs-based methods, mutagenesis and PROTAC treatments followed by Western Blot or mass spectrometry for functional analyses. Viability and apoptosis after drug treatments was assessed in vitro by metabolic readouts, synergy was determined using matrix layouts.

RESULTS

We identified ubiquitin-specific protease 7 (USP7), a known cancer regulator with multiple inhibitors available as direct interaction partner of EZHIP in PFA. We confirmed their interaction in PFA cells and showed that the EZHIP-USP7 interaction is independent of EZH2, a separate interactor of both. Functionally, we show that USP7 de-ubiquitinates EZHIP, preventing its degradation and thus stabilizing it, mediated via the six lysine residues present in EZHIP. We reveal a vulnerability of PFA cells to genetically engineered losses of EZHIP and USP7. Moreover, USP7 inhibitors highly affected the survival and induced apoptosis in different PFA cell lines at a low micromolar IC50 in vitro. Mid-throughput drug library screens additionally identified BET inhibitors as synergistic partners. In vivo treatments with the combination of USP7 and clinically achievable doses of BET inhibitors in PFA PDX models are ongoing.

CONCLUSIONS

USP7 de-ubiquitinates and thus stabilizes EZHIP, which qualifies it as a candidate therapeutic target in pediatric PFA ependymoma.
EPEN-18. MULTI-OMICS APPROACH REVEALED A TIGHT BLOOD-BRAIN BARRIER IN EPENDYMOMA
Authors: Sundheimer Julia K , Benzel Julia , Federico Aniello , Knoll Maximilian , Gansert Cornelia , Statz Britta , Scheuermann Sophia , Seitz Christian , Kool Marcel , Pfister Stefan M , Maaß Kendra K , Pajtler Kristian W
Published: June 2024

BACKGROUND

A major challenge in the treatment of brain tumors is the limited penetration of many drugs through the blood-brain barrier (BBB). BBB characteristics include endothelial cells connected by tight junction proteins (e.g. Claudin5, ZO1, occludin) and the expression of efflux transporters (e.g. P-gp) with the physiological role to limit the accumulation of potentially toxic substances in brain tissue. Our study aims to enhance our understanding of the BBB composition across different molecular groups of ependymoma (EPN) with the goal of leveraging this knowledge to improve therapeutic strategies against these tumors.

METHODS

We applied a multi-omics approach integrating single-nuclear RNA sequencing and ultra-high content imaging to unravel BBB composition at both transcriptomic and proteomic levels. Patient-derived xenograft (PDX) models were utilized to explore differences in BBB penetration between tumor and healthy brain tissue following drug treatments.

RESULTS

Expression of tight junction and transporter proteins revealed strong dependencies specific to molecular groups, but were independent of the corresponding brain regions. Human tissue of ST-EPN-ZFTA exhibited highest expression of claudin5, while both ST-EPN-ZFTA and PF-EPN-A represented upregulation of occludin and ZO1 in comparison to healthy tissue. These findings on claudin5 and ZO1 were further confirmed in PDX models. Single-cell data analysis from patients localized the expression of relevant BBB factors to tumor-associated endothelial cells. Treatment of PDX models with drugs revealed disparities in drug penetration between EPN tumors and healthy brain regions. Notably, for most drugs BBB penetration was lower in ST-EPN-ZFTA tumors than healthy brain region.

CONCLUSIONS

Molecular BBB specifics may contribute to drug resistance of aggressive EPN particularly in ST-EPN-ZFTA tumors, which presented high tight junction expressions and lower drug penetration. This resource aims to improve BBB penetration prediction in EPN, to identify combination therapies targeting BBB components and to select innovative drug delivery approaches.
METB-13. GERMLINE GENETIC TESTING IN CHILDREN WITH CNS TUMORS; FIRST-EVER EXPERIENCE FROM JORDAN
Authors: Amer Shrouq , Shanap Mayada Abu , Amayiri Nisreen
Published: June 2024

BACKGROUND

It is expected that 10-15% of children with CNS tumors have an underlying cancer predisposition syndrome (CPS). This has important implications on treatment, cancer screening and family counseling. There is no published data on this genetic risk from Jordan.

METHODS

We retrospectively reviewed the medical charts of the Jordanian children <18 years old at the time of diagnosis with CNS tumors, and were treated at King Hussein Cancer Center/Jordan between January 2021 and December 2023. We reviewed their clinical characteristics and tumor diagnoses, then applied the updated Jongmans’ criteria and MIPOGG criteria and linked that with their germline genetic testing result if performed.

RESULTS

We identified 198 children (53% males); median age at diagnosis was 7years (range, 0-18 years). Consanguinity was found in 30% of families, and 35% had first/second degree relatives with cancer. Most common diagnoses were LGG (41%), HGG (22%) and medulloblastoma (14%). Most tumors were non-metastatic (90%) at initial diagnosis. Fifty-five percent of patients fulfilled the updated Jongmans’ criteria and 36% the MIPOGG criteria, however germline genetic testing was only performed for 34 patients (17%). Pathogenic germline variants were found in 15 patients (44%); 6 LGG (NF1 (3), TSC2, PTPN11, MUTYH), 4 medulloblastoma (SDHB, TP53, BRCA2, CHEK2), 4 HGG (MSH6 (3), TP53), and one had pathogenic NF2 gene. The presence of CPS affected the management received: children with NF1 were treated without tumor biopsy, the child with TSC2 received everolimus, and 3 children with MSH6 received checkpoint inhibitors instead of temozolomide. The underlying CPS also predicted prognosis e.g. rapid clinical deterioration in the TP53-mutated-SHH-medulloblastoma. Partial screening was provided to children with NF1, TSC, NF2, TP53 and BMMRD mutations.

CONCLUSIONS

High proportion of our patients fulfilled the criteria for referral to genetic clinic, but less than half were referred. Increasing awareness of these criteria is important. Identification of CPS impacted treatment and prognosis, yet families’ perceptions and attitudes toward these CPS need to be captured.
GCT-02. OPTIC PATHWAY PRIMARY GERMINOMA: DON´T MISS THE DIAGNOSIS
Authors: Campo Regina M Navarro-Martin del , Huerta-Hurtado Alma M , Saldaña-Alcalá David , Orozco-Alvarado Ana L
Published: June 2024

BACKGROUND

Germ Cell tumors usually arise in the midline of brain; location in optic pathway (OP) is extremely rare. This case illustrates an OP primary Germinoma.

METHODS

A 9 years old female debuted with diminished visual acuity, it was diagnosed and treated as optic neuritis without improvement, a MRI evidenced a gadolinium enhancement with a very subtle thickening on the optic chiasm, along 3 non conclusive vascular like images in the left Virchow space. A differential diagnosis between endophytic Optic pathway glioma and germ cell tumor was made.

RESULTS

Assessment of AFP and Sub HCG in both blood and CFS was negative, endocrine evaluation confirmed Diabetes insipidus. A stereotaxic biopsy was performed and Pathology confirmed a Pure Germinoma. Non metastatic disease was confirmed as negative Spine MRI and acellular CFS. As a relevant familiar History the father had testicular Germinoma in his teenage. She was treated with 9 weeks of Carboplatin/V16 and radiotherapy as follows: whole ventricular 24 Gy and primary site 16.5 Gy for a total dose of 40.05 Gy. She is free of tumor at 3 follow up years with improvement in visual acuity and arginine vasopressin dependence.

CONCLUSIONS

This case illustrates a germ cell tumor primary arising in the optic pathway and aware us to consider it as a differential diagnosis with non-exophytic optic pathway Glioma being the biopsy mandatory to establish the correct diagnosis
GCT-11. CENTRAL NERVOUS SYSTEM GERM TUMORS (CNS GCTS): RESULTS FROM A SINGLE INSTITUTION IN BRAZIL - SÃO PAULO UNIVERSITY
Authors: Barreto Juliana S , Campoy Mirela L , de Azambuja Alessandra M P , Ribas Felippe G O , Sanders Felipe H , Baraldi Helena E , Weltaman Eduardo , Ferracioli Suely F , Lucato Leandro T , Casal Yuri R , Novak Estela M , Gimenez Thamiris M , Komatsu Mariana M , Cristofani Lilian M , Filho Vicente Odone
Published: June 2024

INTRODUCTION

Central Nervous System Germ Tumors (CNS GCTs) are broadly classified as germinomatous (commonly called germinoma) and non-germinomatous germ cell tumors (NGGCTs) based on clinicopathological and laboratory characteristics, including tumor markers.

OBJECTIVES

Compare data from patients admitted from 2000 to 2023, with the usual presentation in the literature, identifying possible specific variables.

METHODOLOGY

Retrospective study involving 27 patients admitted to the institution without previous treatment.

RESULTS

In western countries, GCTs account for 3% to 4% of primary brain tumors in children, with a peak incidence between 10 and 19 years of age. In Japan and other Asian countries, one series reported that the incidence of GCTs in the CNS consists of approximately 15% of all pediatric CNS tumors. The genetic or environmental reasons for these differences remain unknown. In general, males have a higher incidence of GCT than females. Male patients have a preponderance of primary tumors of the pineal region. The data collected by our institution are compatible with those in the literature.

CONCLUSION

Our discussion and data analysis on GCTs are comparable to those presented in the literature, with the majority of cases treated being: adolescents between 10 and 15 years old, predominantly male and with a satisfactory response to therapy.
GCT-17. EXPLORING NEW THRESHOLDS FOR BETA-HCG IN CENTRAL NERVOUS SYSTEM GERMINOMA
Authors: Krawczyk Malgorzata A , Acar Simge , Wang Jinli , Bartels Ute , Abdelbaki Mohamed S
Published: June 2024

BACKGROUND

Human chorionic gonadotropin (beta-HCG) levels in serum and cerebrospinal fluid (CSF) are critical in the management of patients with germinoma. The threshold for beta-HCG diagnosis is a topic of debate and differs in Europe, ≤50 IU/L, North America ≤100 IU/L, and ≤200 IU/L in Brazil/Japan.

METHODS

We conducted a meta-analysis of English-language publications (1990-2023) to assess how beta-HCG cut-off levels impact treatment outcomes. Standard descriptive statistics summarized all data.

RESULTS

Forty-nine patients with biopsied germinoma were identified. Eighteen had beta-HCG level of 50-100 IU/L (cohort 1), 21 had 100-200 IU/L (cohort 2), and 10 had >200 IU/L (cohort 3). In cohort 1, treatment with chemotherapy plus radiotherapy was administered to 9 patients. Eight of them received radiotherapy like germinoma treatment (≤30Gy), primarily employing whole ventricle irradiation (WVI). Nine patients received radiotherapy alone with total dose 30-59.6Gy. Fifteen patients in cohort 2 received chemotherapy plus radiotherapy. Eight of them received radiotherapy ≤30Gy for different fields [WVI – 4, whole brain (WB) – 3, cerebrospinal irradiation (CSI) – 1). In 7 patients the dose of radiotherapy exceeded 30Gy (local radiotherapy – 4, CSI – 3). Radiotherapy alone was used in 5 patients, chemotherapy alone – 1 patient. In cohort 3, radiotherapy only was primarily used. Six patients received CSI (50-54Gy), one – CSI+WB+local radiotherapy (12.8Gy+27.2Gy+50.6Gy). One patient received combined treatment and 2 patients received chemotherapy alone. Relapses occurred in each cohort. In cohort 1 – 2 metastatic relapses (1 after WVI 24Gy, 1 after radiotherapy >30Gy). Three children from cohort 2, who received chemotherapy plus radiotherapy were diagnosed with relapse (1 after WB 23.4Gy, 2 after radiotherapy >30Gy). In cohort 3 two metastatic relapses were diagnosed – only after chemotherapy.

CONCLUSIONS

Relapse rates across all beta-HCG level are similar. However, study groups are small and treatment regimens vary, warranting further investigation.
GCT-21. MULTINATIONAL ANALYSIS OF PEDIATRIC RELAPSED/REFRACTORY CENTRAL NERVOUS SYSTEM NON-GERMINOMATOUS GERM CELL TUMORS
Authors: Abu-Arja Mohammad Hatim , McGlynn Mary Claire , Zaghloul Mohammed Saad , Elhemaly Ahmed , Bertrand Kelsey , Gajjar Ammar , Ronsley Rebecca , Cappellano Andrea M , Dassi Natalia , Czogala Malgorzata , Graham Richard , Knowles Truman , Meuller Sabine , Dhall Girish , Nagabushan Sumanth , Abdelbaki Mohamed S
Published: June 2024

BACKGROUND

Patients with relapsed/refractory central nervous system (CNS) non-germinomatous germ cell tumors (NGGCTs) have poor prognosis. We explored prognostic factors to guide the management of these patients.

METHODS

We performed a multinational retrospective study of relapsed/refractory CNS NGGCTs. Data were summarized using standard descriptive statistics. Overall survival (OS) was evaluated using Kaplan-Meier and Fisher’s exact test to estimate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

We identified 31 patients from eight centers. The median age at initial diagnosis was 11 years (interquartile range (IQR): 9-15.3). Twenty patients (64.5%) suffered a relapse, and 11 patients (35.5%) had refractory disease. The median follow-up time since relapse/progression was 17.5 months (range:1-295). The median time to relapse/progression was 12.1 months (IQR: 5.5-27.5). Ten patients (32.3%) received high-dose chemotherapy (HDCx) with stem cell rescue. Sixteen patients (51.6%) received re-irradiation at relapse/progression. Nine patients (29%) achieved complete remission (CR). Ten patients (32.3%) were alive at the time of the last follow-up. Among the ten survivors, the median serum and cerebrospinal fluid (CSF) alpha-fetoprotein levels were 2.3 ng/dl (range: 0-17) and 2.1 ng/dl (range: 0-55), respectively, the median serum and CSF beta-human chorionic gonadotropin were 23 IU/L (0-168) and 139 IU/L(0-601), none underwent gross total resection, eight received HDCx, and seven received radiotherapy (craniospinal irradiation (n=6), abdominal radiotherapy (n=1)). HDCx (OR=19.8, 95%CI: 2.7-145.7; p=0.01) and achieving CR at the end of relapse treatment (OR=160, 95%CI: 8.9-2880.5; p=<0.001) were associated with a survival benefit. Re-irradiation (OR=3.3 95%CI: 0.53-20.9; p=0.24) was not associated with a survival benefit.

CONCLUSIONS

A subset of patients with relapsed NGGCTs are salvageable at relapse. HDCx and achieving CR at the end of relapse therapy were associated with a survival benefit. More studies are required to identify these patients who would benefit from salvage therapy.
GCT-22. MEDICAL AND SURGICAL VARIABLES ASSOCIATED WITH RELAPSE IN CENTRAL NERVOUS SYSTEM (CNS) NONGERMINOMATOUS GERM CELL TUMORS (NGGCTS): SECONDARY ANALYSIS OF STRATUM 1 OF THE CHILDREN’S ONCOLOGY GROUP ACNS1123 PHASE 2 CLINICAL TRIAL
Authors: Nagabushan Sumanth , Yan Rachel , Lin Tong , Onar-Thomas Arzu , Souweidane Mark M , Dhall Girish
Published: June 2024

BACKGROUND

ACNS1123 was a Phase 2 trial that evaluated the survival benefit of whole ventricular irradiation (WVI) instead of craniospinal irradiation in children with localized CNS NGGCTs who achieved a complete/partial radiographic response (CR/PR) to induction chemotherapy with negative tumor markers (beta-HCG/AFP) in serum and cerebrospinal fluid (CSF). Patients who did not achieve a CR/PR were considered inevaluable and removed from study therapy post-induction.

METHODS

In unplanned, exploratory analyses, we evaluated the association of age <15/>15-years at diagnosis, tumor location (pineal/suprasellar/bifocal/ventricular), tumor markers (beta-HCG/AFP) in serum and cerebrospinal fluid (CSF) at baseline (>/<1000), and rate of decline during induction in CR/PR and <CR/PR patients. Since most evaluable patients with relapse experienced distant failure in the spine, we assessed the impact of surgical variables, such as endoscopic third ventriculostomy (ETV)/biopsy/resection/combination, on spinal relapse in patients with or without disease progression.

RESULTS

66 of 107 eligible patients achieved CR/PR with negative tumor markers while 41 patients did not. Bifocal tumors appeared to demonstrate a higher hazard for disease progression compared to suprasellar tumors (Hazard Ratio=5.4; p=0.0279). Otherwise, we did not find an association with progression-free-survival for any of the analyzed medical variables. Of 66 evaluable patients who received WVI, eight patients experienced relapse, with all patients demonstrating disease in the spine. No significant association was detected between any surgical variable (ETV/biopsy/resection) and spinal failure among evaluable patients who did or did not relapse; however, we had very limited power for these analyses due to very few events.

CONCLUSION

Current reliance on conventional parameters appears inadequate to identify biomarkers of response as well as relapse. Innovative approaches such as comprehensive genomic profiling of primary and recurrence tumor specimens could inform somatic clonal evolution and potential targeted therapies.
GCT-23. LONG-TERM FOLLOW-UP AND SURVIVALS OF PATIENTS WITH LOCALIZED CENTRAL NERVOUS SYSTEM NON-GERMINOMATOUS GERM CELL TUMORS (NGGCT) ENROLLED ON ACNS1123: A CHILDREN’S ONCOLOGY GROUP (COG) STUDY
Authors: Dhall Girish , Wang Yu , Onar-Thomas Arzu , Shaw Dennis , MacDonald Shannon , Murphy Erin , Khatua Soumen , Bartels Ute , Fangusaro Jason
Published: June 2024

BACKGROUND

ACNS1123 was a Phase 2 study to determine whether irradiation could be safely reduced without impacting survival in a subgroup of NGGCT patients.

METHODS

Patients with localized disease who achieved a complete (CR) or partial response (PR) to induction chemotherapy were eligible to receive reduced dose/volume of irradiation to 30.6Gy whole ventricular field with 54Gy tumor-bed boost.

RESULTS

107 eligible NGGCT patients were accrued. The median age of patients at enrollment was 11 years (3.7-21.6). Eighty patients (75%) were male. Location was pineal in 58 (55%), suprasellar in 37 (35%), ventricles in 6 (6%), and bifocal in 6 patients (6%). Sixty-six (61.7%) patients achieved a CR/PR post-induction and were eligible and evaluable for the primary objective and received reduced dose and volume of irradiation. Eight patients progressed; 6 had a distant spinal relapse (outside the irradiation field) and 2 had a local plus distant relapse. As of December 31, 2023, the median follow-up time for eligible and evaluable patients was 5.6 years (0.9-7.9) from enrollment. Except for an unrelated death due to SARS-CoV-2 at 5.5 years from enrollment, there were no grade 3 or higher adverse events at the 60-month follow-up timepoint and no disease progressions beyond 2 years. The 5-year progression-free and overall survival for all eligible and evaluable patients are 87.9% (95% CI:79%-94.8%) and 92.4% (95% CI:82.8%- 96.8%), respectively.

CONCLUSION

Although the study was closed prematurely due to the concern of increased spinal relapse, the current data suggest that most patients with localized NGGCT and a CR/PR to chemotherapy will survive long-term, and, in fact, have similar survival (PFS and OS) to patients enrolled on ACNS0122 who received full dose craniospinal irradiation. The key to future biologic studies and clinical trials is identifying at diagnosis those patients at high risk for relapse.
GCT-27. Β-HCG STIMULATION WITH RAPIDLY PROGRESSIVE PUBERTY (PP) IN INTRACRANIAL NON-GERMINOMATOUS GCT (NGGCT): CASE REPORT
Authors: Yilmaz Yasin , Salhah Hiba , Mattera Emily , Damilano Cecilia , Bakjaji Shadi , Mamilly Leena , Thomas Diana , Shaikhouni Ammar , Khan Sara
Published: June 2024

BACKGROUND

Intracranial non-germinomatous are rare heterogenous group of Central Nervous System (CNS) tumors that consist of embryonal carcinomas, yolk sac tumors, choriocarcinomas, and teratomas (mature, immature), with or without malignant transformation, as well as mixed types. Presentation frequently includes endocrinopathies, visual changes and signs of raised intracranial pressure.

CASE

We present a 9-year-old boy with history of headaches, voice changes, increased height and muscle mass, and new onset pubic hair for one month. Examination showed mild papilledema with no cranial nerve palsies, advanced linear growth with height velocity of 15.8 cm/yr with height and weight at 94th and 85th percentile respectively for age. Tanner 2 pubic hair, muscular body habitus and testicles volume of 10-12mLs bilaterally. MRI brain showed a localized pineal region mass with obstructive hydrocephalus. Tumor markers were elevated in serum (β-hCG;69 IU/l and AFP;36.8 ng/ml) with high CSF β-hCG of 41 IU/l with AFP <10ng/ml. Work up for advanced puberty showed bone age of 11.3yrs. Markedly elevated testosterone levels at 929 ng/dl with free testosterone of 135 pg/m. Both LH and FSH were undetectable supporting the diagnosis of peripheral non-gonadotropic puberty (PP). Diagnosis of NGGCT was established on biopsy. He received therapy with chemotherapy, second look surgery and radiation. He remains in remission (negative tumors markers and MRI). Interestingly initiation of therapy resulted in age-appropriate testosterone level and slowing down of rapidly progressive puberty clinically.

CONCLUSION

We herein present a rare association of β-hCG secreted by NGGCT that cross-reacts with testicular and adrenal LH receptors resulting in increased testosterone levels and rapidly progressive or precocious puberty in males. The incidence of PP in pineal NGGCT remains unknown with very few cases reported in the literature however these are an important consideration in children with advanced puberty in the absence of exogenous hormone exposure and or non-CNS etiologies.
HGG-05. GLUCOSE CONJUGATION FOR THE SPECIFIC TARGETING AND TREATMENT OF GLIOBLASTOMA
Authors: Iorio Anna Lisa , Lenci Elena , Marzano Chiara , Tirinnanzi Bianca , Giunti Laura , Fonte Carla , Guidi Milena , Tellini Marco , Castelli Barbara , Nicola Marco Di , Trabocchi Andrea , Sardi Iacopo
Published: June 2024

BACKGROUND

Malignant brain tumors, such as Glioblastoma (GBM), are a major challenge in oncology with a dismal prognosis. This can be in part explained by the inability to deliver more effective drugs, as Doxorubicin (DOX), into the brain because of resistance mechanisms. Malignant tumors as GBM also show an elevated glycolytic rate through glucose transporters and GLUT1 is reported to be the main mediator of BBB glucose uptake. For these reasons, we have developed an innovative approach able to increase drug efficiency and selectivity, by conjugating the anticancer agents DOX to glucose.

METHODS

Two glycoconjugates (EB73 and EB74) were synthesized, using an oxime-based linkers between position 6 of glucose and carbonyl group of DOX, and characterized for absorbance, fluorescence and binding affinity to ctDNA. The cytotoxic effect of EB73 and EB74 was evaluated in two GBM cell lines (A172 and T98G). These cells were also used to study the effect of glucose deprivation on GLUT1 and breast cancer resistance protein (BCRP) expression. Moreover, cellular uptake of the glicoconjugates was evaluate in an in vitro BBB model and by immunofluorescence (IF) in GBM cells.

RESULTS

Our results indicated that EB73 and EB74 maintained Ka binding constants comparable to DOX, confirming that functionalization with glucose did not alter DOX intercalation capability and fluorescence. The cytotoxicity results demonstrated that EB74 has the major effect in A172 and T98G DOX-resistant cells starting from 24h of treatment. Moreover, glucose deprivation showed a GLUT1 overexpression and BCRP downregulation in both cell lines improving EB74 efficacy. BBB in vitro model and IF experiments revealed that only EB74 is able to accumulate in cells nuclei as conventional DOX

CONCLUSION

In conclusion, these results indicated that glycoconjugation of DOX and glucose deprivation may be helpful instruments to increase drugs uptake and effectiveness in aggressive and chemoresistant tumor cells.