bluuebunny/crossref_metadata_2025_split huggingface dataset:
TAMI-20. POLY(ADP-RIBOSE) GLYCOHYDROLASE INHIBITION SEQUESTERS NAD+ TO POTENTIATE THE METABOLIC LETHALITY OF ALKYLATING CHEMOTHERAPY IN IDH MUTANT TUMOR CELLS
Authors: Nagashima Hiroaki , Lee Christine , Tateishi Kensuke , Higuchi Fumi , Subramanian Megha , Rafferty Seamus , Melamed Lisa , Miller Julie , Wakimoto Hiroaki , Cahill Daniel 
Published: December 2020

Abstract
Mutations in IDH1 or IDH2 characterize the majority of diffuse infiltrative gliomas of younger adulthood. DNA alkylator chemotherapy has proven to be an effective treatment for IDH mutant glioma, yet recurrences remain frequent and improved treatments are needed. Upon exposure of cancer cells to DNA alkylating agents, poly(ADP-ribose) polymerases (PARPs) catalyze the transient oligomerization of nicotinamide adenine dinucleotide (NAD+) into poly-ADP-ribose (PAR) chain-assemblies, which stimulate the DNA damage response. Here, we find that, in IDH mutant glioma cells, alkylator-induced cytotoxicity is dramatically augmented by pharmacologic inhibition or genetic knockout of the PAR breakdown enzyme poly(ADP-ribose) glycohydrolase (PARG). Mechanistically, we show this augmentation is driven by a metabolic state pairing amplified alkylator-induced DNA damage with catastrophic depletion of NAD+. IDH mutant cancer cells have low basal levels of NAD+, rendering them vulnerable to prolonged NAD+ depletion. Either of two clinically-utilized monofunctional alkylators, procarbazine (PCZ) or temozolomide (TMZ), when exposed to multiple IDH mutant lines, activated PARP conversion of cellular NAD+ monomers into polymerized PAR. Subsequent PAR breakdown and recycling of NAD+ monomers was then halted by concomitant PARG inactivation, amplifying PARylation-mediated DNA damage signaling and critically depleting free NAD+, resulting in profound cytotoxicity. This effect was partially reversed by NAD+ rescue supplementation, confirming the key contribution of metabolic stress. Combined alkylator treatment and PARG inhibition in vivo maximized both NAD+ depletion and cytotoxicity in an endogenous IDH mutant cancer model. Thus, alkyating DNA damaging agents expose a metabolic liability in IDH mutant cancers, and subsequent targeted blockade of PAR breakdown and NAD+ metabolite recovery can exploit this vulnerability to provide genotype-specific therapeutic benefit.
TAMI-29. MULTIFACTORIAL UPREGULATION OF ID1 DRIVES DIPG INVASIVENESS AND IS THERAPEUTICALLY TARGETABLE
Authors: Nand Yadav Viveka , Harris Micah K , Stallard Stefanie , Woo Rinette , Siddaway Robert , Qin Tingting , Cummings Jessica , Mullan Brendan , Miklja Zachary , Siada Ruby , Ravindran Ramya , Cao Xuhong , Pasternak Amy , Castro Maria G , Lowenstein Pedro , Mody Rajen , Chinnaiyan Arul , Hawkins Cynthia , Desprez Pierre , McAllister Sean , Venneti Sriram , Koschmann Carl 
Published: December 2020

Abstract
Diffuse intrinsic pontine gliomas (DIPGs) are lethal brain tumors with no effective therapies other than radiation. Inhibitor of DNA binding (ID) proteins, key regulators of lineage commitment during embryogenesis, are implicated in tumorigenesis in multiple human cancers. Prior work showed that recurrent H3F3A and ACVR1 mutations increase ID1 expression in cultured astrocytes. However, this has not been validated in human DIPG. The regulation and targetability of ID1 in DIPG has not been explored either. Exome and transcriptome sequencing analysis of multi-focal DIPG tumors and normal brain tissue from autopsy (n=52) revealed that ID1 expression is significantly elevated in DIPG tissues. Higher ID1 expression correlates with reduced survival in DIPG patients and increased regional invasion in multi-focal autopsy samples. Analyses of developing mouse brain RNA/ChiP-Seq data revealed high ID1 expression and H3K27ac promoter binding in prenatal hind brain compared to all other prenatal and postnatal brain regions. ChIP-qPCR for H3K27ac and H3K27me3 revealed that ID1 gene regulatory regions are epigenetically poised for upregulation in DIPG tissues compared to normal brain, regardless of H3/ACVR1 mutational status. These data support that the developing pons is regionally poised for ID1 activation. Genetic (shRNA) ID1 knockdown in primary human H3.3K27M-DIPG cells (DIPG007) resulted in significantly reduced invasion and migration in vitro. Additionally, DIPG-ID1-KO cells showed improved sensitivity to radiation therapy. Phospho-kinase array analysis of DIPG cells revealed that Akt and WNK1 activity were significantly downregulated upon ID1 knockdown, which was previously shown in lung tumors. Treatment of DIPG007 cells with cannabidiol (CBD) reduced ID1 expression levels and viability/proliferation of DIPG cells in vitro. ID1 knockdown and CBD treatment studies in vivo are ongoing. In summary, our findings indicate that multifactorial (genetic and regional) epigenetic upregulation of ID1 drives DIPG invasiveness and targeting ID1 using CBD may be a potential strategy for the treatment of DIPGs.
TAMI-33. AURKA INHIBITION REPROGRAMS METABOLISM AND IS SYNTHETICALLY LETHAL WITH FATTY ACID OXIDATION INHIBITION IN GLIOBLASTOMA
Authors: Nguyen Trang , Shang Enyuan , Shu Chang , Mela Angeliki , Humala Nelson , Mahajan Aayushi , Quinzii Catarina , Westhoff Mike-Andrew , Karpel-Massler Georg , Bruce Jeffrey , Canoll Peter , Siegelin Markus 
Published: December 2020

Abstract
Aurora kinase A (AURKA) has emerged as a viable drug target for glioblastoma (GBM), the most common malignant primary brain tumor in adults with a life expectancy of 12-15 months. However, resistance to therapy remains a critical issue, which partially may be driven by reprogramming of metabolism. By integration of transcriptome, chromatin immunoprecipitation with sequencing (CHIP-seq.), assay for transposase-accessible chromatin with sequencing (ATAC-seq.), proteomic and metabolite screening followed by carbon tracing (U-13C-Glucose, U-13C-Glutamine and U-13C-Palmitic acid) and extracellular flux analysis we provided evidence that genetic (shRNA and CRISPR/Cas9) and pharmacological (Alisertib) AURKA inhibition elicited substantial metabolic reprogramming mediated in part by inhibition of MYC targets and concomitant activation of PPARA (e.g. PGC1A) signaling. While glycolysis was suppressed by AURKA inhibition, we noted a compensatory increase in oxygen consumption rate (OCR) fueled by fatty acid oxidation (FAO). Whereas interference with AURKA elicited a suppression of c-Myc, we detected an upregulation of PGC1A, a master regulator of oxidative metabolism, upon AURKA inhibition. Silencing of PGC1A reversed the increase in OCR and sensitized GBM cells to AURKA inhibition mediated reduction in cellular viability. CHIP experiments confirmed binding of c-Myc to the promoter region of PGC1A, which is abrogated by AURKA inhibition and in turn unleashed PGC1A expression. ATAC-seq. confirmed higher accessibility of the MYC binding region within the PGC1A promoter. Forced expression of c-Myc blocked AURKA inhibition mediated increase of PGC1A, suggesting that c-Myc acted as a repressor. To interfere with this oxidative metabolic reprogramming, we combined AURKA inhibitors with blockers of FAO (etomoxir), which elicited substantial synergistic growth inhibition and extension of overall survival in orthotopic patient derived xenografts of GBM in mice without induction of toxicity in normal tissue. Taken together, these data support that simultaneous targeting of oxidative metabolism and AURKA inhibition might be a potential novel therapy against GBM.
TAMI-34. SEX-SPECIFIC METABOLIC ADAPTATIONS TO THE KETOGENIC DIET IN A MOUSE MODEL OF GLIOBLASTOMA
Authors: Zhang Shanshan , Sponagel Jasmin , Rubin Joshua , Ippolito Joseph 
Published: December 2020

Abstract
Glioblastoma (GBM) is a lethal brain tumor that has a higher incidence and mortality in males compared to females. GBM tumors consume glucose and glutamine as the major fuels for growth and strategies have been developed that disrupt these nutrient utilization pathways. Both pre-clinical and clinical reports have identified the ketogenic diet (KD) as an approach which consists of high fat and low carbohydrates. It reduces circulating glucose and increases ketones resulting in restricted tumor growth. Because of published studies showing that carbohydrate utilization is higher in healthy males, we hypothesized that the KD would have greater inhibition of male GBM growth. We compared sex differences in response to the KD using an established GBM mouse model (Nf1-/-DNp53), which has previously yielded important insights into sex differences in GBM. Flank tumors were implanted and tumor size measurements were performed. Unexpectedly, the KD had no effect on male GBM tumor growth, but female tumors grew significantly slower in mice that were on the KD compared to control diet. To understand how male GBM tumors adapt their metabolism to the KD, we measured serial blood glucose and ketone levels. We discovered expected physiologic responses to the KD with decreased serum glucose and increased serum ketones, suggesting that males adapt to the KD through changes in cell-intrinsic metabolism. Using FDG-PET imaging to investigate glucose utilization, we found that FDG uptake was increased in both tumor and normal brain of male but not female mice that were on the KD compared to control diet. Taken together, our results show that the KD has a greater impact on female GBM tumor growth and that sex differences in metabolic adaptations such as increased glucose transport may underlie the male-specific resistance to the KD. This study has the potential to develop sex-specific metabolic treatment approaches for GBM.
TAMI-38. CYSTEINE-PROMOTING COMPOUNDS INDUCE MITOCHONDRIAL TOXICITY IN GLIOBLASTOMA THROUGH ALTERED PYRUVATE AND SERINE METABOLISM
Authors: Noch Evan , Palma Laura , Yim Isaiah , Binder Bhavneet , Benedetti Elisa , Krumsiek Jan , Elemento Olivier , Cantley Lewis 
Published: December 2020

Abstract
Glioblastoma (GBM) remains a poorly treatable disease with high mortality. Tumor metabolism in GBM is a critical mechanism responsible for accelerated growth because of upregulation of glucose, amino acid, and fatty acid utilization. However, little is known about the metabolic alterations that are specific to GBM and that are targetable with FDA-approved compounds. To investigate tumor metabolism signatures unique to GBM, we interrogated the TCGA and a cancer metabolite database for alterations in glucose and amino acid signatures in GBM relative to other human cancers and relative to low-grade glioma. From these analyses, we found that GBM exhibits the highest levels of cysteine and methionine pathway gene expression of 32 human cancers and that GBM exhibits high levels of cysteine-related metabolites compared to low-grade gliomas. To study the role of cysteine in GBM pathogenesis, we treated patient-derived GBM cells with a variety of FDA-approved cyst(e)ine-promoting compounds in vitro, including N-acetylcysteine (NAC) and the cephalosporin antibiotic, Ceftriaxone (CTX), which induces cystine import through System Xc transporter upregulation. Cysteine-promoting compounds, including NAC and CTX, inhibit growth of GBM cells, which is exacerbated by glucose deprivation. This growth inhibition is associated with reduced mitochondrial metabolism, manifest by reduction in ATP, NADPH/NADP+ ratio, mitochondrial membrane potential, and oxygen consumption rate. Metabolic tracing experiments with 13C6-glucose demonstrate that L-serine is rapidly depleted in GBM cells upon treatment with NAC and CTX, and exogenous serine rescues NAC- and CTX-mediated cell growth inhibition. In addition, these compounds reduce GBM mitochondrial pyruvate transport. We show that cysteine-promoting compounds reduce cell growth and induce mitochondrial toxicity in GBM, which may be due to rapid serine depletion and reduced mitochondrial pyruvate transport. This metabolic phenotype is exacerbated by glucose deprivation. This pathway is targetable with FDA-approved cysteine-promoting compounds and could synergize with glucose-lowering treatments, including the ketogenic diet, for GBM.
TAMI-43. IMPACT OF SEX AND RADIATION ON IRON TRAFFICKING IN BONE MARROW DERIVED MACROPHAGES
Authors: Shenoy Ganesh , Snyder Amanda , Slagle-Webb Becky , Marshall Savannah , Schell Todd , Chroneos Zissis , Davalos Dimitrios , Berens Michael , Lathia Justin , Barnholtz-Sloan Jill S , Rubin Joshua , Connor James 
Published: December 2020

Abstract
The tumor microenvironment in glioblastoma provides cancer cells with favorable conditions to proliferate and invade surrounding tissues. Macrophages comprise a large portion of the glioblastoma tumor microenvironment (TME) both in terms of volume and function. These cells have been reported to influence tumor progression by modulating immune responses, remodeling extracellular matrix, and providing nutrients to cancer cells among numerous other functions. Radiation therapy forms one of the pillars of glioblastoma management along with surgical resection and chemotherapy. Here we investigated the effects of radiation on macrophage iron metabolism. Using mouse bone-marrow-derived macrophages (BMDMs) we performed in-vitro 59Fe radiotracer assays to study how radiation exposure modified iron trafficking in these cells. We found that low dose radiation at 0.25, 0.5, or 2 Gy from a 60Co source stimulated iron release from the BMDMs with maximal release occurring at 0.5 Gy. Moreover, we observed that iron release was dependent on the amount of serum present in culture media with cells cultured in 20% fetal bovine serum (FBS) showing reduced iron release profiles compared to those cultured in 10% or 1% FBS. Since glioblastoma patients exhibit sexually dimorphic survival outcomes, we investigated whether these radiation-induced responses occurred in a sexually dimorphic pattern. At radiation doses of 0.25 Gy we observed that male macrophages tended to release more iron than female macrophages despite no differences in iron uptake between the sexes – raising the question as to whether differential iron trafficking in response to treatment contributes to the poorer survival outcomes observed in males. Our data suggest that delineating how supporting cells such as macrophages respond to glioblastoma treatment regimens may provide insights into addressing mechanisms of treatment resistance and further our understanding of the sexual dimorphism observed in patient outcomes.
TAMI-45. PHENOGENOMIC CHARACTERIZATION OF IMMUNOMODULATORY PURINERGIC SIGNALING IN GLIOBLASTOMA
Authors: Coy Shannon , Rashid Rumana , Stopka Sylwia , Lin Jia-Ren , Euskirchen Philipp , Hwang Jaeho , Khadka Prasidda , Bandopadhayay Pratiti , Wen Patrick , Sorger Peter , Agar Nathalie Y R , Ligon Keith , Touat Mehdi , Santagata Sandro 
Published: December 2020

Abstract

INTRODUCTION
Purinergic signaling plays critical roles in the regulation of tumor growth and anti-tumor immunity via autocrine/paracrine binding of metabolites to receptors on neoplastic and non-neoplastic populations. Extracellular purine concentrations are mediated by the ectonucleotidase enzymes CD39 and CD73, which catabolize ATP to adenosine. Within tumors such as glioblastoma, neoplastic, immune, and stromal cells expressing these enzymes may co-localize to generate immunosuppressive adenosine-rich environments. However, the composition, architecture, and phenotypic properties of these tumor ecosystems and their relationship to tumor genotype are poorly characterized.

METHODS
We quantified CD73 expression by immunohistochemistry in a cohort of CNS tumors [meningiomas(n=222), gliomas(n=244), ependymomas(n=44), medulloblastomas(n=24), and craniopharyngiomas(n=38)]. We used publicly-available single-cell RNA-seq data and 36-marker multiplexed tissue imaging (t-CyCIF) of 139 clinically and genomically annotated glioblastoma resections to characterize CD39 and CD73-expressing populations, define the immune architecture and tumor cell-states at single cell resolution, and identify markers of clinical outcome. We used mass spectrometry imaging (MALDI-MSI) to generate spatially-resolved quantification of purine metabolite levels in glioblastoma resections (n=10).

RESULTS
CD73 exhibited strong expression in a subset of gliomas and meningiomas but was typically not expressed in ependymomas or medulloblastomas. CD73 expression correlated with poor progression-free-survival in IDH-wildtype glioblastoma (p=0.04). scRNA-seq and t-CyCIF in glioblastoma showed CD73 expression in tumor cells, and CD39 expression in macrophages and endothelial cells. MALDI-MSI showed significantly greater adenosine concentrations (3.5-fold;p=0.04) in glioblastomas with high CD73 expression. scRNA-seq showed direct correlations between stem-like mRNA expression, proliferation, and CD73 expression in DIPG. CD73 expression significantly correlated with EGFR amplification, interferon signaling, and PD-L1 expression in glioblastoma.

CONCLUSIONS
Phenogenomic analysis of purinergic immunomodulatory signaling revealed significant interplay between CD73 activity and genotype, adenosine concentration, differentiation-state, clinical outcome, and possible interaction between CD39-positive macrophages and CD73-positive neoplastic cells. Anti-CD73 therapy may provide therapeutic benefits in glioblastoma by blunting immunosuppressive and oncogenic adenosine signaling.
TAMI-46. TNFα SECRETED BY GLIOMA ASSOCIATED MACROPHAGES PROMOTES ENDOTHELIAL ACTIVATION AND RESISTANCE AGAINST ANTI-ANGIOGENIC THERAPY
Authors: Wei Qingxia , Singh Olivia , Ekinci Can , Gill Jaspreet , Li Mira , Yasin Mamatjan , Karimi Shirin , Bunda Severa , Mansouri Sheila , Aldape Kenneth , Zadeh Gelareh 
Published: December 2020

Abstract
Glioblastoma (GBM) remains a universal fatal disease and improving survival remains a challenge. One of the most prominent features of GBM is hyper-vascularization, characterized by abnormally dilated, distorted, and leaky vessels. Bone marrow (BM)-derived macrophages are recognized to be an important host cell population that are actively recruited to the tumor and referred to as glioma-associated macrophages (GAMs). GAMs are found to associate closely with blood vessels, and thought to provide a critical role in tumor neo-vascularization. However, the mechanisms by which GAMs regulate and promote endothelial cells (ECs) in the process of tumor vascularization and response to anti-angiogenic therapy (AATx) is not understood. To understand how GBM, GAMs and EC interacts, we designed and developed a novel GBMs-GAMs-EC co-culture system as well as a unique in vivo model in which the BM of NOD/SCID mice were reconstituted with red fluorescent protein (RFP)-BM cells to create a chimeric mouse and then using intracranial injection of GFP-U87 cells to create a GBM xenograft. Our study is the first to demonstrate that glioma cells-secreted IL8 and CCL2 which stimulate GAMs to secrete TNFα and promote EC activation. TNFα inhibition led to normalization of the tumor vasculature and significant improvement in survival in glioma mice model. More importantly, we validate these findings using clinical data showing that TNFα is a predictor of overall survival and response to AATx in GBM patients. We further demonstrated that increased macrophage recruitment and upregulation of TNFα in GAMs activating EC in response to bevacizumab treatment is one of the critical molecular mechanisms underlying the failure of AATx in GBM. Collectively, these results provide compelling evidence to further explore the clinical impact of inhibiting TNFα concurrent with AATx.
TAMI-57. MEDULLOBLASTOMA UTILIZE GABA TRANSAMINASE TO SURVIVE IN THE CEREBROSPINAL FLUID MICROENVIRONMENT AND PROMOTE LEPTOMENINGEAL DISSEMINATION
Authors: Martirosian Vahan , Deshpande Krutika , Zhou Hao , Shen Keyue , Stepanosyan Vazgen , Remsik Jan , Boire Adrienne , Isakov Danielle , De Feyter Henk , Hurth Kyle , Nakamura Brooke , Shao Ling , Northcott Paul , Wiemels Joe , Li Shaobo , Neman Josh 
Published: December 2020

Abstract
Medulloblastoma (MB) is a malignant pediatric brain tumor. Studies have shown heterogeneous cells amongst the tumor bulk which mirror normal neural cells in various neurodevelopmental stages. To discern exploited mechanisms promoting MB leptomeningeal disease, we drew conclusions from developmental neurobiology. In normal differentiation, the metabolic phenotype in proliferating neural progenitor cells evolves from a glycolysis-dependent to an oxidative phosphorylation-reliant energetic profile in quiescent differentiated neurons. Cancer cells mirror this evolution, which also grants them the capability to utilize alternative nutrients in the microenvironment as an energy source. Considering metastatic cells are typically in a dormant state and primarily utilize oxidative phosphorylation, we hypothesized metastatic MB cells emulate a quiescent neuron-like cellular profile to survive in the cerebrospinal fluid and form leptomeningeal metastases. To examine this, we query the expression of GABA catabolic enzyme GABA transaminase (ABAT) in MB. GABA is found in the cerebellar and leptomeningeal microenvironments, and is utilized by metastatic cancer cells in the CNS as an energy source. We correlate an increase in ABAT expression with neurodevelopment and show heterogeneous expression of this protein in primary MB tumors. MB cells with increased expression of ABAT were slower-dividing, expressed a genetic and metabolic phenotype reminiscent of quiescent neuron-like cells, and had increased capability to metabolize GABA. Conversely, lower expression of ABAT was associated with an increased proliferation rate and correlated with a progenitor-like cellular profile. Transplantation of MB cells into the leptomeningeal compartment decreased proliferative capacity and enhanced ABAT expression. Xenograft models showed MB cells with ABAT knockdown had increased growth in the cerebellar microenvironment. Conversely, MB cells with ABAT overexpression transplanted into the cerebrospinal fluid formed leptomeningeal metastases whereas ABAT knockdown cells could not. These results suggest ABAT expression in MB cells can be modulated by the tumor microenvironment and is required to form leptomeningeal metastases.