bluuebunny/crossref_metadata_2025 huggingface dataset:
SURG-56. TRANSCRIPTION FACTOR CELL LINEAGE DETERMINES AGGRESSIVE BEHAVIOR AMONG NONFUNCTIONAL PITUITARY ADENOMAS
Authors: Himstead Alexander , Fote Gianna , Acharya Nischal , Kuan Edward , Hsu Frank , Mohyeldin Ahmed
Published: November 2024

INTRODUCTION

Pituitary neuroendocrine tumors (PitNETs) are the second most common intracranial neoplasm. Silent or non-functional PitNETs represent a common neuro-oncological challenge due to their size and unpredictable invasion of parasellar structures. This makes their complete surgical resection difficult and puts patients at higher risk for recurrence.

OBJECTIVE

To characterize differences in tumor volume, cavernous sinus invasion, and recurrence in nonfunctional PitNETs.

METHODS

Out of 615 transsphenoidal surgeries from 2012 to 2024, there were 309 overall PitNETs and 181 nonfunctional PitNETs. Based on new WHO criteria for transcription factor profiling (PIT-1, TPIT, and SF-1), there were 98 silent gonadotroph adenomas (SGA), 31 silent corticotroph adenomas (SCA), 10 silent pleurihormonal tumors (PHT), and 2 null cell adenomas. Tumor volume was calculated using (AxBxC/2). Knosp grade was calculated. Cavernous sinus invasion was defined as Knosp ≥ 3. Residual disease at 3 months postoperative was recorded and surgical intervention for growing residual disease was captured.

RESULTS

Average tumor volume of PHT (18.08 cm3) was significantly higher than SGA (8.44 cm3, p=0.007) and similar to SCA (10.33 cm3, p=0.11). Percentage of cavernous sinus invasion was significantly different between SCA (31.82%) and SGA (10.20%, p=0.003), but not PHT (33.33%; p>0.05). There was a significantly higher residual rate in SCA compared to SGA (31.71% vs. 11.22%, p=0.006). There were significantly more reoperations in the SCA group compared to SGA and PHT.

CONCLUSIONS

Despite similar tumor volume between SCA and SGA, there was a significantly higher rate of cavernous sinus invasion and residual disease among SCA. This has important neuro-oncological implications regarding surgical technique, postoperative surveillance, and need for adjuvant therapy to mitigate aggressive recurrent disease.
TMET-05. INCREASING GLUTAMINE UPTAKE-LIPOGENESIS AXIS PROMOTES TUMOR RESISTANCE TO LYSOSOME INHIBITION
Authors: Zhong Yaogang , Geng Feng , Mazik Logan , Yin Xinmin , Becker Aline Paixao , Mohammed Shabber , Su Huali , Xing Enming , Kou Yongjun , Chiang Chengyao , Fan Yunzhou , Li Pui-Kai , Mo Xiaokui , Lefai Etienne , He Liqing , Cheng Xiaolin , Zhang Xiang , Chakravarti Arnab , Guo Deliang
Published: November 2024

An effective therapy for glioblastoma (GBM), the most lethal brain tumor, is lacking1-11. Several antipsychotic drugs, including pimozide, have recently been shown to have anti-GBM potential 12,13, but the development of tumor resistance diminishes their efficacy. Identifying the mechanisms for such resistance will help repurpose these brain-penetrant drugs for GBM therapy. Here, we found that pimozide inhibits cholesterol and fatty acids (FAs) release via lysosome-mediated lipid droplets (LDs) and lipoprotein hydrolysis, starving GBM cells of these essential building blocks. However, we identified that GBM cells become resistant to pimozide-based therapy due to an elevation of glutamine metabolism. Mechanistically, reductions in cholesterol and the promotion of signaling via sterol regulatory element-binding protein 1 (SREBP-1), a classical lipogenic transcription factor14, stimulate glutamine transporter ASCT2 expression, increasing glutamine uptake and consumption. Enhanced glutamine uptake leads to the release of ammonia that further stimulates SREBP-1 activation, thereby forming a feedforward loop to concurrently increase both glutamine metabolism and lipid synthesis, resulting in drug resistance. Pharmacological targeting of either ASCT2, or glutaminase (GLS) to limit glutaminolysis, abolishes this loop, and in combination with pimozide result in marked killing of GBM cells. Our study demonstrates that combinatorial targeting of glutamine metabolism and lysosomal function is a promising approach to treat GBM, which may be applicable to other aggressive cancers that are also addictive to glutamine and lipids.
TMET-16. GABA PRODUCTION INDUCED BY IMIPRIDONES IS A TARGETABLE AND IMAGEABLE METABOLIC ALTERATION IN DIFFUSE MIDLINE GLIOMAS
Authors: Batsios Georgios , Udutha Suresh , Taglang Celine , Gillespie Anne Marie , Lau Benison , Ji Sunjong , Phoenix Timothy , Mueller Sabine , Venneti Sriram , Koschmann Carl , Viswanath Pavithra
Published: November 2024

Diffuse midline gliomas (DMGs) are lethal brain tumors in children. The imipridones ONC201 and ONC206 have emerged as promising therapies for DMG patients, but efficacy as monotherapy is limited. Another hurdle is the lack of biomarkers that report on drug-target engagement at an early timepoint after treatment. Here, using 1H-magnetic resonance spectroscopy (1H-MRS), which is a non-invasive method of quantifying metabolite pool sizes, we show that imipridones induce accumulation of gamma-aminobutyric acid (GABA) in patient-derived (BT245, SF8628) and syngeneic (26-B7, 26-C2) cells. Importantly, in vivo1H-MRS detects a significant increase in GABA within a week of ONC206 treatment, when anatomical alterations are absent, in mice bearing orthotopic BT245, SF8628 or 26-B7 xenografts. Mechanistic studies show that imipridones activate the mitochondrial protease ClpP and upregulate the stress-responsive transcription factor ATF4. ATF4, in turn, upregulates glutamate decarboxylase, the enzyme that synthesizes GABA, and downregulates GABA transaminase, which degrades GABA, leading to GABA accumulation in DMG cells and orthotopic tumors. Since GABA is known to regulate oxidative stress signaling and since imipridones induce oxidative stress, we assessed whether GABA influences oxidative stress in DMG cells. Our studies indicate that GABA induces expression of superoxide dismutase (SOD1), which scavenges superoxide radicals and, thereby, curbs apoptosis induced by imipridones. The biological effects of GABA are mediated via signaling cascades triggered by GABA receptors and we find that GABA acts in an autocrine manner via the GABAB receptor to upregulate SOD1. Importantly, the clinically translatable GABAB receptor antagonist SGS742 and the SOD1 inhibitor ATN-224 exacerbate oxidative stress and synergistically induce apoptosis in combination with imipridones in DMG cells. Furthermore, SGS742 is brain-penetrant and potentiates ONC206-induced apoptosis in mice bearing orthotopic SF8628 xenografts in vivo. Collectively, we identify GABA as a unique metabolic adaptation to imipridones that can be leveraged for imaging drug-target engagement and for enhancing response to therapy. Clinical translation of our studies will enable precision therapy and imaging for DMG patients.
TMET-19. REWIRING OF CORTICAL GLUCOSE METABOLISM FUELS HUMAN BRAIN CANCER GROWTH
Authors: Scott Andrew , Mittal Anjali , Meghdadi Baharan , Palavalasa Sravya , Achreja Abhinav , O’Brien Alexandra , Kothari Ayesha , Zhou Weihua , Xu Jie , Lin Angelica , Wilder-Romans Kari , Edwards Donna , Wu Zhe , Feng Jiane , Andren Anthony , Zhang Li , Tarnal Vijay , Redic Kimberly , Qi Nathan , Fischer Joshua , Yang Ethan , Regan Michael , Stopka Sylwia , Baquer Gerard , Lawrence Theodore , Venneti Sriram , Agar Nathalie , Lyssiotis Costas , Al-Holou Wajd , Nagrath Deepak , Wahl Daniel
Published: November 2024

The brain avidly consumes glucose to fuel neurophysiology. Cancers of the brain, such as glioblastoma (GBM), lose aspects of normal biology and gain the ability to proliferate and invade healthy tissue. How brain cancers rewire glucose utilization to fuel these processes is poorly understood. Here we perform infusions of 13C-labeled glucose into patients and mice with brain cancer to define the metabolic fates of glucose-derived carbon in tumor and cortex. By combining these measurements with quantitative metabolic flux analysis, we find that human cortex funnels glucose-derived carbons towards physiologic processes including TCA cycle oxidation and neurotransmitter synthesis. In contrast, brain cancers downregulate these physiologic processes, scavenge alternative carbon sources from the environment, and instead use glucose-derived carbons to produce molecules needed for proliferation and invasion. In particular, we find that cortical tissue produces its own glucose-derived serine, whereas gliomas predominantly consume serine from the environment. Targeting this metabolic rewiring in mice through dietary modulation selectively alters GBM metabolism and slows tumor growth. Combining dietary serine restriction with chemoradiation reduces brain tumor growth in mice, suggesting that such a dietary intervention could improve outcomes for patients with high grade glioma.
TMET-21. METABOLIC PROFILING OF MENINGIOMA REVEALS NOVEL SUBGROUP-SPECIFIC BIOLOGIC INSIGHTS AND OUTCOME DEPENDENCIES
Authors: Landry Alexander , Wang Justin , Liu Jeff , Patil Vikas , Zhang Wen-Jiang , Ellenbogen Yosef , Gui Chloe , Ajisebutu Andrew , Kislinger Thomas , Chen Eric , Nassiri Farshad , Zadeh Gelareh
Published: November 2024

BACKGROUND

Prior studies have elucidated the presence of four consensus molecular groups (MGs) of meningioma, with unique underlying biology and outcomes. The hyperactivation of metabolic pathways may be associated with tumour growth in so-called hypermetabolic (MG3) tumours, and there is a need to better understand the metabolic profiles of these tumours. This study is the first to study the global metabolon of meningioma in the context of modern molecular subgroups.

METHODS

We performed untargeted metabolic profiling of 53 meningiomas representing each MG and WHO grade. Prognostic biochemicals were identified using Cox regression and further investigated using RNA and protein-based pathway analyses. A larger cohort with available RNA sequencing (n=121) was used to further explore the prognostic influence of relevant pathways, and biochemicals of interest were validated on a subset of these samples (n=35) using targeted high performance liquid chromatography (HPLC).

RESULTS

Our untargeted approach identified 560 unique biochemicals for downstream analysis. The abundance of N6-trimethyllysine was associated with significantly earlier time to recurrence highly prognostic on our whole cohort (HR [95%CI] = 3.18 [1.45-26.23], p = 0.004) and within hypermetabolic (MG3) tumours (HR [95%CI] = 6.73 [1.72-6.97], p = 0.006); pyruvate was with worse outcomes in proliferative (MG4) tumours specifically (HR [95%CI] = 5.65 [1.073-29.71], p = 0.041). Analysis of implicated gene pathways demonstrated that upregulation of the oxidative phosphorylation pathway portends worse outcomes in the hypermetabolic subgroup but better outcomes in the proliferative subgroup. By contrast, upregulated lactate transporters were associated with worse outcomes in proliferative, but not hypermetabolic, meningiomas.

CONCLUSIONS

This is the first study to demonstrate a subgroup-specific prognostic role of N6-trimethyllysine and pyruvate in meningioma, offering increasingly granular outcome predictions using a widely accessible technique (HPLC). In addition, we demonstrated key differences in energy utilization between hypermetabolic and proliferative tumours suggesting fundamental differences in preferred energy utilization and reinforcing a need for subgroup-specific therapies.
TMET-26. TARGETING TRANSSULFURATION VIA SUPPRESSION OF THYROID HORMONE SIGNALING: A WINDOW OF OPPORTUNITY TRIAL OF METHIMAZOLE IN PATIENTS WITH PROGRESSIVE WHO GRADE 4 GLIOMAS (NCT05607407)
Authors: Peereboom David , Lathia Justin , Angelov Lilyana , Barnett G H , Cordova Christine , Dhawan Andrew , Hage Lea El , Grabowsky Matthew , Hufsey Rachel , Lobbous Mina , Malkin Mark , Mohammadi Alireza , Ponti Andras , Silver D J , Soni Pranay , Stevens Glen , Torres-Trejo Alejandro , Yang Kailin , Hine Christopher
Published: November 2024

BACKGROUND

Gaseous hydrogen sulfide (H2S), a by-product of cysteine metabolism, inhibits cancer cell behavior and growth in glioblastoma (GBM) models. H2S production capacity (HPC) is decreased in human GBM specimens compared to non-tumor controls. Thus, boosting HPC is a novel strategy for GBM treatment. Suppression of thyroid hormone signaling increases endogenous production of H2S. Hypothesis: hypothyroidism induced by methimazole will enhance the efficacy of chemotherapy in WHO grade 4 gliomas by increasing HPC within the tumor. Goal: proof of concept that methimazole, by reducing thyroid hormone signaling, can increase HPC in patients with WHO grade 4 gliomas (G4G).

METHODS

This window of opportunity trial evaluates safety, HPC in plasma and tumor, and efficacy of methimazole + chemotherapy in patients with progressive G4G.

MAIN OBJECTIVE

10% increase in HPC and a 1.5-fold increase in peripheral blood sulfhydration signaling. Patients planned for a clinically-indicated resection receive pre-op (5-7 days) and post-op methimazole with the addition of investigator’s choice of chemotherapy 1 month after starting post op methimazole. Patients receive methimazole + chemotherapy until progression. Pre- and post-op plasma and resected tumor tissue are assayed for HPC and proteins relevant to H2S production. Key eligibility: progressive G4G for whom a clinically-indicated resection is planned; normal thyroid function with no history of thyroid dysfunction. Patients may have received unlimited prior regimens including bevacizumab.

RESULTS

To date 12 patients (8 male) median age 56 years enrolled, 3 of whom are in pre-op phase. Relative to age/sex matched control, post-methimazole plasma at all time points tested but not tumor HPC increased (minimum increase 56%, p 0.041). No grade 3-5 toxicities or significant changes in thyroid function tests. PFS6 0 for first 6 patients.

CONCLUSIONS

Induction of subclinical hypothyroidism is feasible and safe in recurrent GBM with significant increases in plasma but not tumor HPC. The protocol is being modified to increase methimazole doses and allow earlier addition (10 days) of post-op chemotherapy.
TMET-29. TARGETING IDH1-MUTATED OLIGODENDROGLIOMA WITH ACID CERAMIDASE INHIBITORS
Authors: Muley Vilamu Helena , Dowdy Tyrone , Zaibaq Faris , Larion Mioara
Published: November 2024

BACKGROUND

Currently, an estimated 14,950 people lives with oligodendroglioma in the United States. Oligodendroglioma is genetically defined as a tumor harboring isocitrate dehydrogenase 1 or 2 mutations (IDH1mut/IDH2mut). Previously, we reported that in IDH1mut gliomas, D-2HG, the product of IDH1 mutant enzyme produces an increase in monounsaturated fatty acid levels that are incorporated into ceramides, tilting the S1P-to-ceramide rheostat toward apoptosis. Herein, we exploited this imbalance to further induce and IDHmut-specific glioma cell death.

METHODS

TCGA and CCGA data were used to explore the association between acid ceramidase (AC) gene expression and patient survival. CCK8 viability assays were carried out to measure the sensitivity of glioma cell lines to acid ceramidase inhibitors. Western blot and liquid chromatography-mass spectrometry analyses were performed for studying the mechanism of action of acid ceramidase inhibitors. The in vivo efficacy of the SABRAC drug, an irreversible inhibitor of AC, was evaluated in an orthotopic oligodendroglioma xenograft mice model using TS603 patient-derived oligodendroglioma cells. RESULTS. We report for the first time that the inhibition of acid ceramidase (AC) induces apoptosis and increases the survival of mice with IDH1mut oligodendroglioma. We demonstrated an IDH1mut-specific cytotoxicity of SABRAC, in patient-derived oligodendroglioma cells. Exploring the mechanism of action of this drug, we found that SABRAC activates both extrinsic and intrinsic apoptosis in an ER stress-independent manner, pointing to a direct action of AC-related ceramides in mitochondria permeability. The activation of apoptosis detected under SABRAC treatment was associated with up to a 30-fold increase in some ceramide levels and its derivatives from the salvage pathway.

CONCLUSIONS

We propose AC as a novel therapeutic target in oligodendroglioma with IDH1mut and we are conducting additional preclinical testing.
TMET-31. OXIDATIVE STRESS INDUCED PROTEIN AGGREGATION VIA GGCT PRODUCED PYROGLUTAMIC ACID IN DRUG RESISTANT GLIOBLASTOMA
Authors: Tiek Deanna , Song Xiao , Wu Runxin , Yu Xiaozhou , Iglesia Rebeca , Hu Bo , Cheng Shiyuan
Published: November 2024

Drug resistance is a major barrier to cancer therapies and remains poorly understood. Recently, non-mutational mechanisms of drug resistance have been proposed where a more plastic metabolic response can play a major role. Here, we show that upon drug resistance, glioblastoma (GBM) cells have increased oxidative stress, mitochondria function, and protein aggregation. Gamma (y)-glutamylcyclotranserase (GGCT), an enzyme in the y-glutamyl cycle for glutathione production, located on chromosome 7 which is commonly amplified in GBM is also increased upon resistance. We further observe that the byproduct of GGCT – pyroglutamic acid – can bind aggregating proteins and that genetic and pharmacological inhibition of GGCT prevents protein aggregation. Finally, we found increased protein aggregation, GGCT expression, and pyroglutamic acid staining in recurrent GBM patient samples, as well as adjacent normal brain. These findings suggest a new pathway for protein aggregation within drug resistant brain cancer that should be further studied in other brain disorders.
TMET-32. THE ROLE OF HOXC10 IN DRIVING GLIOBLASTOMA AGGRESSIVENESS
Authors: Vengoji Raghupathy , Perumalsamy Balaji , Thiraviyam Anand , Ogunleye Ayoola , Jain Maneesh , Ponnusamy Moorthy , Batra Surinder , Shonka Nicole
Published: November 2024

BACKGROUND

Glioblastoma (GBM) is an aggressive malignancy, with a tumor doubling time of just 49.6 days. Despite maximal safe surgical resection, radiation, and temozolomide, median survival is only 14.6 months. Homeobox gene, homeobox C10 (HOXC10), a transcription factor of the HOX10 family, is pivotal in neuronal development, upregulated in several cancers, including glioma, and correlates with poor survival.

METHODS

RNA sequencing analysis was done on our mouse glioma syngeneic cell lines. HOXC10 expression analysis was done on human and mouse GBM cell lines and tissues by immunoblotting and immunohistochemistry, respectively. HOXC10 and p16-/-silencing were done using 4 unique 29mer shRNA constructs in the GFP vector, respectively. Gene Ontology predicted HOXC10 functions. HOXC10 and pyrroline-5-carboxylic acid reductase 1 (PYCR 1), a proline biosynthetic enzyme co-expression was studied using immunofluorescence analysis.

RESULTS

HOXC10 is highly expressed in human and mouse GBM tissues. HOXC10 was upregulated only in the high-grade/aggressive cell line [EGFRvIII; p16-/- & GFAP Cre] and demonstrated increased expression with p16 deletion in the mouse glioma cell line. Compellingly, TCGA analysis of GBM correlated the negatively prognostic p16 homozygous deletion (HD) with HOXC10 upregulation. Gene Ontology supports the role of HOXC10 for proline biosynthesis and metabolism. Immunofluorescence on mouse GBM sections revealed co-expression of HOXC10 and PYCR1. HOXC10 silencing significantly decreased GBM cell line proliferation, induced apoptosis, and decreased PYCR1 expression in vitro.

CONCLUSIONS

HOXC10 expression is increased in GBM and with p16 HD. HOXC10 silencing significantly decreased GBM cell line proliferation and decreased PYCR1 expression. HOXC10-mediated proline biosynthesis may present a novel target to improve GBM survival.
TMET-33. INVESTIGATING THE ROLE OF CHEMERIN SIGNALING IN GLIOBLASTOMA
Authors: Dessa Brianna , Wang Dazhi , Welford Scott
Published: November 2024

Glioblastoma multiforme (GBM) is one of the most common and lethal primary brain tumors in adults. Despite clinical efforts, patient prognosis remains poor with a median survival of approximately 14 months. Thus, identification of novel treatment avenues is needed. Metabolic rewiring is a hallmark of cancer and lipid homeostasis has an increasingly appreciated role in cancer cell survival. It has been shown that the disruption of lipid metabolic balance can lead to lipotoxicity, creating a new avenue in GBM treatment. Therefore, identifying methods to disrupt said lipid metabolic balance in GBM could provide a needed foothold. Previous studies from the lab have identified chemerin, a multifunctional adipokine encoded by the retinoic acid receptor responder 2 (RARRES2) gene, as an important and targetable lipid metabolism modulator in Clear cell renal cell carcinoma (ccRCC). Chemerin has also been implicated in the mesenchymal-phenotype promoting network between GBM cells and tumor-associated macrophages. Given similarities in GBM and ccRCC lipid metabolism and the existing role of chemerin in the tumor immune microenvironment in GBM, we hypothesize that chemerin drives GBM development by regulating lipid metabolism in addition to immune cell trafficking. This study aims to investigate the role and therapeutic opportunities of altered lipid metabolism in GBM by examining chemerin and its receptors (CMKLR1 and GPR1). Immunocompetent GBM mouse models generated through CRISPR-in utero electroporation (IUE) show that mice bearing RARRES2, CMKLR1, and GPR1 knockout tumors have prolonged survival. In addition, in vitro molecular inhibition of CMKLR1 in both human and murine GBM cell lines results in cell death. Ongoing studies involving in vitro CRISPR knockouts of RARRES2, CMKLR1, and GPR1 aim to elucidate the mechanisms by which in vivo inhibition of chemerin signaling results in slower tumor progression.
TMET-34. PYROPTOSIS IS AN ACQUIRED VULNERABILITY OF BRAIN METASTASES
Authors: Mobilio Daniel , Kieliszek Agata , Peterson Erik , Singh Kanwaldeep , Zhai Kui , Miletic Petar , Gwynne William , Ang Patrick , Venugopal Chitra , Chafe Shawn , Berg Tobias , Wahl Daniel , Singh Sheila
Published: November 2024

Metastasis, the spread of cancer cells from one part of the body to another, is a leading cause of death among cancer patients. Three particularly dangerous forms of metastases are the spread of lung, skin, and breast cancers to the brain. On average survival time of all brain metastasis (BM) patients is around 4 months, which is accompanied by a failing and undefined standard of care. We have strived to bridge the gap between novel safe therapeutics and brain metastasis patients by discovering and targeting metabolic vulnerabilities in brain metastases. Here, we conducted comparative metabolomic screening in patient-derived BM lines versus normal brain cells to identify dihydroorotate dehydrogenase (DHODH) as a cancer-selective targetable vulnerability. DHODH is an essential enzyme that is located within the inner membrane of the mitochondria which has a primary role in producing pyrimidine metabolites through the de novo uridine synthesis pathway and also contributes to the proper functioning of the electron transport chain. Through this, DHODH has been implicated in the essential functioning of energy metabolism, DNA and RNA synthesis, and most recently in the modulation of the immune system. In our studies we have elucidated the significant effect DHODH inhibitors and the induction of DHODH CRISPR knock-out has against the cell viability, sphere formation, and proliferation of patient derived BM samples in vitro and in vivo. Furthermore, through metabolomics we have discovered that following DHODH perturbation, there is a significant increase in a signaling lipid (D-ethryo-Dihydrosphingosine) that specifically inhibits Protein Kinase C (PKC) and initiates Gasdermin E (GSDME) mediated pyroptosis. By uncovering this mechanism we have discovered GSDME mediated pyroptosis is an aquired vulnerability of brain metastases. Overall, this study highlights the translational potential of DHODH inhibitors in BM and elucidates novel mechanistic underpinnings of nucleotide deprivation within the context of cell death.
TMET-37. TARGETING LIPID MEDIATED NON-CANONICAL CELL DEATH IN MALIGNANT GLIOMA
Authors: Salinas Jennifer , Cadet Dimitri , Smolev Sarina , Iyer Dhruva , Loo Caitlyn , Lee Weaverly , Dixon Scott , Nathanson David
Published: November 2024

Resistance to canonical cell death mechanisms (e.g. apoptosis) is a hallmark of glioma and consequently driving the dismal outcomes of patients with glioma. Recent work has demonstrated gliomas are susceptible to non-apoptotic forms of cell death mediated by rewired lipid metabolism. Here we explored whether gliomas are vulnerable to other lipid-dependent forms of cell death. Our investigation revealed a large subset of patient-derived glioma cells that are exquisitely sensitive to a novel cell death pathway dependent on palmitate. Intriguingly, sensitivity to this type of cell death was linked to glioma tumor cells having a proneural identity and a specific enrichment in sphingolipid metabolic features. The catabolism of glioma sphingolipids established palmitate pools for protein S-palmitoylation, a necessary requirement to trigger palmitate mediated cell death in glioma, which was coupled to the exclusive expression of palmitoyl acyltransferases unique to proneural glioma tumors. Ongoing efforts aim to explore the mechanistic link between glioma identity, lipotype and susceptibility to palmitate dependent lethality. Taken together, these results identify a new approach to drive glioma cell death by targeting non-canonical cell death mediated by rewired glioma lipid metabolism.
TMIC-01. TARGETABLE GENE EXPRESSION CHANGES MEDIATE EXTRAVASATION OF BREAST CANCER CELLS FROM THE CIRCULATION AND LOCAL PROLIFERATION IN THE BRAIN
Authors: Kalistratova Venina , Morshed Ramin , Chalif Eric , Gill Sabraj , Khela Harmon , Lad Meeki , Sati Ankita , Mathur Aakriti , Aghi Manish
Published: November 2024

As breast cancer migrates into the brain, it acquires distinct genomic, immunologic and phenotypic changes through interactions with the local microenvironment. We sought to determine how targetable gene expression changes mediate breast cancer extravasation into and proliferation within the brain. We created a brain metastatic cell line (“brain-seeking”) via serial intracardiac injection of mCherry+ 4T1 breast cancer cells in Balb/c mice and flow cytometry isolation of micrometastases. We conducted in vitro and in-vivo studies to uncover immunological and genetic differences between primary breast cancer and brain metastases. In culture, we observed significant upregulation in adhesion (p=0.01) and invasion (p=0.0004) along with upregulation of adhesion-promoting genes such as Sdc3, Serpine2 or ECM1 in brain-seeking cells. We observed significant differences in survival of Balb/c mice injected intracranially with brain-seeking cells vs. breast cancer cells (p=0.04). In the mammary fat pad (MFP), parental 4T1 cells caused increased mortality vs. brain-seeking cells (p=0.003). This rejection of brain-seeking 4T1 cells in the MFP could be due to prior adaptation to the brain microenvironment, while rejection of parental 4T1 cells in the brain could be due to lacking said adaptations. Consistent with this finding, of 20,382 analyzed genes in both cell lines, 108 related to immune regulation were significantly upregulated in brain-seeking cells including Cxcl1, Dusp1, C3. Flow cytometry showed increased cytotoxic and helper T cells in intracranially injected parental vs. brain-seeking cells (p <0.001). In the MFP, however, 4T1 parental cells displayed CD3+ T cell depletion and an increased number of neutrophils (p <0.05) while the “brain-seeking cells” showed increased numbers of CD3+ and CD4+ cells (p <0.01) and macrophages (p<0.05). This suggests that brain metastases evolve from their primary tumor through adhesive and invasive adaptations promoting extravasation, along with unique immunological adaptations that allow their proliferation free of immune surveillance in the brain microenvironment.
TMIC-02. SINGLE-CELL HIGH-DIMENSIONAL MASS CYTOMETRY (CYTOF) REVEALS IMMUNE LANDSCAPE OF PITUITARY NEUROENDOCRINE TUMORS
Authors: Guo Xiaopeng , Chang Mengqi , Huang Yongsheng , Zhang Fan , Zhao Yuanli , Xing Bing
Published: November 2024

Pituitary neuroendocrine tumors (pitNETs) are a group of neoplasms in the sellar region, ranking as the second most common primary brain tumors, with some exhibiting aggressive behaviors. While immunohistochemical staining has been utilized to characterize the tumor immune microenvironment (TIME) of pitNETs, single-cell analysis remains underexplored. High-dimensional mass cytometry (CyTOF) offers a valuable approach for precise quantification of intratumoral leukocytes and potential therapeutic insights. We prospectively enrolled 56 patients with pitNETs of varying endocrine function, histology, and lineage. CyTOF, employing heavy metal-tagged antibodies, was employed to simultaneously measure 37 cellular parameters at single-cell resolution. Analysis revealed a total of 71,049 CD45+ immune cells. Macrophages (mean, 50.7%) and T cells (mean, 28.7%) were the predominant leukocytes, followed by NK cells, dendritic cells, B cells, and neutrophils. The immune cell composition within the TIME exhibited heterogeneity, with distinct patterns observed between functioning and non-functioning pitNETs. Functioning pitNETs displayed fewer macrophages (28.9% vs. 62.9%) and more T cells (44.9% vs. 19.6%) compared to non-functioning pitNETs. Subgroups within functioning (somatotroph, mammosomatotroph, lactotroph) and those within non-functioning pitNETs (null-cell, gonadotroph, corticotroph) shared similar immune profiles, respectively. PIT-1 lineage pitNETs demonstrated a T cell-dominated pattern, while SF-1, T-PIT, and null-cell lineage pitNETs exhibited macrophage predominance. In functioning pitNETs, macrophage abundance negatively correlated with invasiveness, Ki-67 index, and recurrence, while CD4 T cells showed positive correlations. Further unsupervised clustering identified 27 subpopulations of intratumoral immune cells, with some serving as critical predictors of tumor behavior. Our study provides a comprehensive single-cell immune profile of pitNETs, revealing distinct features across subtypes and targeted therapeutic implications.
TMIC-03. CARD9 BLOCKADE OFFERS A NEW OPPORTUNITY TO REPROGRAM TUMOR-ASSOCIATED MACROPHAGES IN GLIOBLASTOMA
Authors: Hofstatter Azambuja Juliana , Yerneni Saigopalakrishna , Maurer Lisa , Crentsil Hannah , Debom Gabriela , Klei Linda , Smyers Mei , Sneiderman Chaim , Schwab Kristina , Acharya Rajesh , Wu Yijen Lin , Ekambaram Prasanna , Hu Dong , Gough Pete , Foley Kevin , Bertin John , Melnick Ari , Kohanbash Gary , Bao Riyue , Lucas Peter , McAllister-Lucas Linda
Published: November 2024

BACKGROUND

Glioblastoma (GBM), one of the deadliest primary tumors of the central nervous system, is characterized by a highly immunosuppressive tumor microenvironment (TME). Tumor-associated macrophages and microglia (TAMs) are a dominant population of immune cells in the GBM TME and substantially contribute to immunosuppression, tumor progression, and treatment resistance. Elucidating the molecular mechanisms underlying TAM behavior is crucial to the development of effective immuno-therapeutic strategies for treating GBM. The adaptor protein, Caspase Recruitment Domain-containing protein 9 (CARD9) is primarily expressed in myeloid cells and its activation triggers assembly of the CARD9-BCL10-MALT1 (CBM) complex, which then promotes activation of NF-κB and/or MAPK pathways. The aim of this study was to investigate the role of the CBM complex in the GBM TME and assess its potential as a therapeutic target.

METHODS/RESULTS

In silico analyses revealed that GBM tumors demonstrate increased CARD9 and MALT1 expression in comparison to non-tumor brain tissue, with CARD9 expressed only within the myeloid compartment. Using co-culture, scratch wound, and transwell assays, we found that GBM tumor cells induce macrophage M2 polarization and migration via a mechanism that is dependent on CARD9/MALT1 signaling within macrophages. scRNA-Seq and flow-cytometric analysis of orthotopic syngeneic immunocompetent GBM tumor models revealed that the GBM TME is dominated by macrophages. Disruption of MALT1 protease activity within the TME leads to reduced tumor infiltration by immunosuppressive TAMs, remodeling of TAMs toward an immunoreactive anti-tumor phenotype, and improved survival of GBM-bearing mice. Additionally, we found that tumor growth was abrogated when GBM-bearing mice were treated with either a MALT1-protease inhibitor or a CARD9 inhibitor.

CONCLUSIONS

Our study suggests that blockade of the CARD9-MALT1 signaling axis impairs GBM-induced macrophage recruitment and M2 polarization and inhibits tumor progression. These findings nominate the CARD9-MALT1 signaling axis as a new target for TAM-directed immunotherapy for the treatment of GBM.
TMIC-05. AGING-SPECIFIC MICRORNA EXPRESSION SIGNATURE IN ELDERLY GLIOBLASTOMA
Authors: Yamashita Daisuke , Ohtsuka Yoshihiro , Takeda Haruna , Kusakabe Kosuke , Nishikawa Masahiro , Suehiro Satoshi , Inoue Akihiro , Watanabe Hideaki , Kondo Toru , Motohoshi Hozumi , Kunieda Takeharu
Published: November 2024

PURPOSE

The rise in aging population worldwide is increasing death from cancer, including glioblastoma. MicroRNAs (miRNAs/miRs) are small non-coding RNAs that mediate the posttranscriptional silencing of specific target mRNAs and that are currently recognized as important regulators of tumorigenesis and development. Here, we explore the impact of brain aging and aging-specific miRNAs on elderly glioblastomas.

METHODS

We comprehensively analyzed miRNAs expression using the TCGA dataset and identified miRNAs that are specifically expressed in elderly glioblastomas. To create the Ehime Glioma Genome Atlas (EGGA), RNA sequencing was performed using tumor tissues from 8 glioblastoma patients (4 elderly and 4 non-elderly). First, we evaluated the impact of the identified miRNAs on prognosis using TCGA and CGGA datasets and searched for target genes of specific miRNAs using TargetScan. The expression patterns of the identified target genes were verified using EGGA, TCGA, and CGGA datasets.

RESULTS

We divided the TCGA dataset into elderly and non-elderly groups based on three ages (75 years-old, 70 years-old, and 65 years-old) and analyzed the expression of miRNAs in tumor tissues. There were 3 miRNAs that showed abnormalities (1 increased miRNA, 2 decreased miRNAs), and among these, miR-210 (increased expression) and miR-507 (increased expression) were identified as miRNAs related to prognosis. Next, we analyzed the expression of EGGA and identified 410 mRNAs (368 increased mRNAs, 42 decreased mRNAs) that showed significantly abnormal expression in the elderly group. The target genes searched using TargetScan were 4,048 genes for miR-210 and 4,704 genes for miR-507. When compared with the 410 genes identified using EGGA, PLA2G3, a target gene to miR-507, was identified. The expression of PLA2G3 was also specifically increased in elderly glioblastoma in the TCGA dataset, and it had a strong influence on prognosis.

CONCLUSION

Our results found an aging-specific miRNA “miR-507” and its target gene “PLA2G3” that suggested as potential new therapeutic target molecules for improving the prognosis of elderly glioblastomas.
TMIC-06. TUMOR ASSOCIATED MACROPHAGES DRIVE TUMOR PROGRESSION AND ARE TRANSCRIPTIONALLY SHAPED BY HISTONE MUTATIONS IN DIFFUSE MIDLINE GLIOMA
Authors: Ross James , Puigdelloses-Vallcorba Montserrat , Pinero Gonzalo , Soni Nishant , Thomason Wes , DeSisto John , Angione Angelo , Tsankova Nadejda , Castro Maria , Schniederjan Matthew , Wadhwani Nitin , Raju G Praveen , Morgenstern Peter , Becher Oren , Green Adam , Tsankov Alexander , Hambardzumyan Dolores
Published: November 2024

Little progress has been made to delineate the inflammatory microenvironment in pediatric high-grade glioma (pHGG) and diffuse midline glioma (DMG). We utilize molecularly defined human samples and immunocompetent mouse models to study how tumor location and genetic driver mutations influence the tumor microenvironment (TME). We first induced tumors of each pHGG/DMG molecular subtype (H3WT, H3G34R, H3.1K27M, H3.3K27M) into both the cortical hemisphere and midline of separate mice and performed survival studies and flow cytometry. The main driving factor shaping the immune landscape and survival is the driver mutation, not tumor location. Next, we performed single cell RNA sequencing on murine H3WT cortical pHGG, H3WT DMG, H3.1 and H3.3K27M DMGs, paired with multiplex flow cytometry. H3K27M DMGs have sparse T cell infiltration and limited T cell recruiting chemokine production. The main non-neoplastic cell type in all tumors was infiltrating myeloid cells and microglia. H3WT DMGs had the greatest myeloid cell and monocyte-derived macrophage (MDM) infiltration, while H3.3K27M DMGs were enriched for microglia. Disease associated gene signatures were found in tumor-associated macrophages (TAMs) that are found in other neurodegenerative diseases, marked by down-regulation of inflammatory signaling, interferon responses, and up-regulation of metabolism-related pathways. H3.3K27M DMGs were enriched for disease-associated TAMs. These gene signatures were then identified in human pHGG/DMG scRNA sequencing data. CD16 monocytes and microglia were enriched for diseased signatures, while CD14 monocytes were pro-inflammatory. We demonstrate that reprogramming this diseased signature in mice results in increased T cell infiltration and extension of survival in H3K27M DMG. Last, through pharmacologic inhibition of CCR1 and CCR5, we demonstrate preventing TAM infiltration in DMG results in enhanced survival, comparable to radiation therapy. Together, this work provides the foundation for developing immunotherapies targeted at specific subgroups of pHGG and DMGs, such as CAR-T-cell, oncolytic viral therapy, and checkpoint blockade.
TMIC-14. RAPID EARLY PROGRESSION IN GLIOBLASTOMA: A COMPREHENSIVE REVIEW OF CLINICAL, IMAGING AND HISTOPATHOLOGICAL FEATURES
Authors: Waqar Mueez , Roncaroli Federico , O’leary Claire , Forte Gabriella , Wright Jenny , Parikh Shefali , Sudell Lindsay , Coope David , Djoukhadar Ibrahim , Borst Gerben
Published: November 2024

BACKGROUND

In glioblastoma patients, Rapid Early Progression (REP) refers to tumour growth between the time of surgery and postoperative chemoradiotherapy. Despite its high incidence relatively little is known about it. The aim of this study was to characterise REP using a combination of clinical, imaging and histopathology data.

METHODS

Ethical approval was obtained. Supratentorial IDH-wildtype glioblastomas undergoing gross-total resection (GTR) between 2015-2021 were included. REP was defined as a nodular increase in enhancement located within or around the surgical cavity, occurring within 6 weeks of surgery, that was not accounted for by initial areas of diffusion-restriction. REP cases were propensity-score matched to controls on baseline characteristics. Imaging was compared using mean apparent diffusion coefficient (ADC) and T1-postcontrast radiomics. Tissue analyses included DNA methylation subtyping and immunohistochemistry for markers of T-cells (CD3), microglia (P2RY12) and proliferation (PHH3).

RESULTS

REP occurred in 8/60 GTR cases (13%) and these patients were matched to 16 controls. REP cases had a worse preoperative performance status (median Eastern Cooperative Oncology Group [ECOG] 2 vs. 1), overall-survival (p=0.038) and progression-free survival (p = 0.029). REP was more common in patients over 65 years (27%) and significantly fewer REP patients received radical postoperative chemoradiotherapy (p=0.023). REP and control cases were well matched with respect to preoperative T1-postcontrast radiomics and mean ADC in enhancing (p=0.99) and non-enhancing regions (p=0.67). There was no relative excess of any one DNA methylation subtype in REP cases. The two groups had a similar proportion of T-cells (p=0.81), but REP cases had a trend towards a higher proportion of microglia (31% vs. 17%; p=0.22), and a lower proliferation rate (3% vs. 9%; p=0.19).

CONCLUSION

REP cases had a worse performance status from diagnosis and received less radical postoperative chemoradiotherapy protocols compared to controls, yielding a significantly shorter median OS/PFS. Differences in immune landscape and proliferation rate should be further investigated.
TMIC-19. EXCESSIVE LIPID PRODUCTION SHAPES GLIOMA TUMOR MICROENVIRONMENT
Authors: Paul Aboubechara John , Maraqah Haitham , Abu-Asab Mones , Lee Han Sung , Aboud Orwa
Published: November 2024

Disrupted lipid metabolism is a characteristic of gliomas. This study utilizes an ultrastructural approach to characterize the prevalence and distribution of lipids within gliomas. This study made use of tissue from IDH1 wild type (IDH1-wt) glioblastoma (n=18) and IDH1 mutant (IDH1-mt) astrocytoma (n=12) tumors. We uncover a prevalent and intriguing surplus of lipids. The bulk of the lipids manifested as sizable cytoplasmic inclusions and extracellular deposits in the tumor microenvironment (TME); in some tumors the lipids were stored in the classical membraneless spheroidal lipid droplets (LDs). Frequently, lipids accumulated inside mitochondria, suggesting possible dysfunction of the beta-oxidation pathway. Additionally, the tumor vasculature has lipid deposits in their lumen and vessel walls; this lipid could have shifted in from the tumor microenvironment or have been produced by the vessel-invading tumor cells. Lipid excess in gliomas stems from disrupted beta-oxidation and dysfunctional oxidative phosphorylation pathways. The implications of this lipid-driven environment include structural support for the tumor cells and protection against immune responses, non-lipophilic drugs, and free radicals.
TMIC-20. UNLOCKING THE POTENTIAL OF HYPOXIA REDUCTION IN RESHAPING THE GLIOBLASTOMA TUMOR MICROENVIRONMENT FOR ENHANCED THERAPEUTIC SYNERGY
Authors: William Ivana , Huntoon Kristin , Lea Spencer , Bhanu Krithikaa Rajkumar , Hegde Shweta , Kim Betty , Curran Michael
Published: November 2024

Glioblastoma (GBM) tumors respond poorly to nearly all cancer therapies due to their highly immunosuppressive tumor microenvironment (TME). Hypoxia exacerbates this immunosuppression by upregulating the hypoxia-inducible factor (HIF) pathway in glioma-associated myeloid cells (GAMs) which suppressively polarizes them to maintain this immune “cold” state. This hypoxia-driven programming inhibits CD8+ T cell infiltration and effector function by inducing metabolic dysfunction, thereby increasing resistance to chemotherapy and T cell immune checkpoint blockade (ICB). Targeting hypoxia thus emerges as a promising strategy to overcome such resistance. Our study suggests that GBM hypoxia ablation can convert the immunosuppressive tumor microenvironment into a more pro-inflammatory one. Tumor hypoxia ablation using the hypoxia-activated prodrug Evofosfamide significantly enhances survival in both GL261 (p<0.0001) and the checkpoint blockade-resistant CT2A murine GBM models (p<0.01). Evofosfamide treatment boosts tumor infiltrating Ki67+ proliferative CD8+ T cells (p<0.001) and heightens cytotoxicity, indicated by increased Granzyme B expression (p<0.01). It also reduces the co-expression of exhaustion markers LAG-3 and TIM-3 (p<0.001), signaling decreased T cell exhaustion. Antigen-specific CD8+ T cells from Evofosfamide-treated primary GBM tumors exhibit enhanced ex vivo killing capacity when co-cultured with GL261-OVA cells (p<0.001). Furthermore, Evofosfamide enhances microglia proliferation and repolarizes them towards a pro-inflammatory state, marked by upregulation of M1 markers such as CD80 (p<0.001) and downregulation of M2 markers like Arginase (p<0.05). Hypoxia reduction also increases chemotherapy sensitivity, synergistically improving survival when combined with the blood-brain barrier-penetrating, immunogenic chemotherapy Berubicin (CT2A; vehicle MS=26d, Evo MS=36d, Berubicin MS=55d, Combo MS=70.5d). Future research will investigate the mechanisms underlying this shift towards a pro-inflammatory state, focusing on metabolic changes in CD8+ T cells and the impact of altered HIF pathway signaling on GAM polarization following hypoxia ablation. Understanding the therapeutic potential of reversing hypoxia-mediated immunosuppression could lead to novel combination therapies capable of overcoming resistance to both chemotherapy and immunotherapy in GBM.
TMIC-28. TITLE: AN IMMUNE-RELATED, SEX-SPECIFIC T-CELL SIGNATURE IN GLIOBLASTOMA MICROENVIRONMENT WITH PROGNOSTIC IMPACT
Authors: Romagnoli Giulia , Offi Martina , Capone Imerio , Tavilla Andrea , Canini Irene , Lapenta Caterina , Buccarelli Mariachiara , Giordano Martina , Tirelli Valentina , Sanchez Massimo , Fragale Alessandra , Giannetti Stefano , Ceccarelli Giovanni Maria , Bonaventura Rina Di , Doglietto Francesco , Olivi Alessandro , Lauretti Liverana , Biffoni Mauro , Ricci-Vitiani Lucia , Pallini Roberto , Gabriele Lucia , D’Alessandris Quintino Giorgio
Published: November 2024

BACKGROUND

Glioblastoma, IDH-wildtype (GBM), is the most prevalent and aggressive primary brain cancer with a poor prognosis. Immune checkpoint inhibitors (ICIs) have been explored in GBM with limited success, highlighting the need for a better understanding of the tumor microenvironment (TME). This study investigated whether the expression of specific immune checkpoints on tissue-resident memory T cells (Trm) predicts patient outcomes.

METHODS

In a single cohort observational study, tumor samples from 45 histologically confirmed GBM patients were processed to obtain single-cell suspensions. Multiparametric flow cytometry was used to analyze the correlation of Trm phenotypes with overall survival (OS) and progression-free survival (PFS). Univariate and multivariate analyses were conducted to assess the prognostic significance of Trm subsets.

RESULTS

Low frequency of exausted Trm expressing programmed cell death protein 1 (PD1) and T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) was associated with better clinical outcomes. Multivariate analysis identified low CD8+CD103+PD1+TIM3+ Trm and Karnofsky performance status (KPS) ≥70 as the most significant independent prognostic factors for longer OS (hazard ratios—HR [95%CI]: 0.14 [0.04–0.52] p < 0.001, 0.39 [0.16–0.96] p = 0.04, respectively). Additionally, younger patients (<63 years) and males had distinct immune profiles affecting prognosis. Notably, the proportion of exausted CD8+CD103+PD1+ Trms had a prognostic correlate only in male patients, consistent with findings by other groups on the existance of gender-specific immune TME in GBM.

CONCLUSIONS

Further exploration of Trm-based immune profiling has the potential to shed light on GBM resistance to ICIs and to help in personalizing treatment strategies.