bluuebunny/crossref_metadata_2025_split huggingface dataset:
TAMI-07. TUMOR-EDUCATED PLATELETS GUIDE BREAST CANCER BRAIN METASTASIS AND PROMOTE THERAPEUTIC RESISTANCE
Authors: Tabet Elie , Tannous Bakhos 
Published: November 2021

Abstract

BACKGROUND
Platelets have been shown to play an important role in systemic and local tumor modulation. Once encountered by tumor cells, platelets are educated to collect and release pro-tumor factors in the tumor/microenvironment, serving as a guiding partner for metastasis. This educational program, however, is not well understood.

METHODS
Wild-type platelets (WTPs) were isolated from blood of healthy humans or mice, whereas tumor-educated platelets (TEPs) were isolated from blood of breast cancer patients or from tumor-bearing donor mice. The tumorigenic and modulatory effect of these two types of platelets on breast cancer was examined in-vitro and in-vivo.

RESULTS
Here, we show that TEPs acquire tumor promoting functions and drive breast cancer progression, metastasis to distal sites specifically the brain, as well as therapeutic resistance. Importantly, TEPs promoted an increased pro-tumorigenic effect on metastatic breast cancer, compared to their wild-type counterpart, promoting epithelial to mesenchymal transition through NF-κB/STAT3 signaling axis via C/EBPβ transcription factor.

CONCLUSION
Our findings point to the important role of TEPs in breast cancer brain metastasis and therapeutic resistance, which could have a major implication in other tumor types, endorsing TEPs as a potential therapeutic target.
TAMI-11. INCREASED M1 MACROPHAGE INFILTRATION CORRELATED WITH POOR PROGNOSIS OF WHO IV GLIOMAS
Authors: Zhou zhaoming , Lai Mingyao , Zhou Jiangfen , Hu Qingjun , Ai Ruyu , Li shaoqun , Zhou Cheng , Cai Linbo 
Published: November 2021

Abstract

BACKGROUND
Gliomas are the malignancy with a poor prognosis. Our previous database mining study demonstrated that M1 macrophage infiltration predicted the survival of GBM patients. Here in this study, we further explored the findings.

METHODS
RNA-seq was performed on 90 WHO IV glioma tissue samples. The sequencing data was investigated with xCell for the cell infiltration levels, and the M1 macrophage infiltration was further analyzed for the prognostic prediction effect with overall survival (OS) data. Differentially expressed genes (DEGs) were calculated between groups and the hub genes were determined by the MCC models in Cytoscape. The survival risk score (SRS) calculating models were established by several machine learning methods, including the least absolute shrinkage and selection operator (LASSO), generalized linear model (GLM), and linear discriminant analysis (LDA).

RESULTS
Compared with M1 macrophages none infiltration, WHO IV gliomas with M1 macrophages infiltration was associated with poor prognosis, and this result remained significant in multivariate analyses (hazard ratio [HR], 0.219; 95% CI, 0.047–0.723; P = 0.035). Protein-to-protein (PPI) network analysis of top 200 up-regulated DEGs determined 10 hub genes (P4HB, PDIA6, LAMB1, PRKCSH, CSF1, LAMB2, LGALS1, RCN1, CALU, and TNC). Further analysis determined that the 10 hub genes were enriched in the ECM-receptor interaction signaling pathway, and six out of the ten gene expressions were confirmed by immunohistochemistry staining. Based on the 6 genes, a survival risk score (SRS) was established by machine learning methods. SRS was able to distinguish the high-risk and low-risk WHO IV gliomas with an AUC = 0.80 [95% CI: 0.74 – 0.86, P &lt; 0.01].

CONCLUSIONS
M1 macrophage infiltration was an unfavorable prognostic biomarker for WHO IV gliomas. ECM-receptor interaction signaling pathway was involved in M1 macrophage infiltration. Hub genes in the signaling pathway could be the potential therapeutic targets for WHO IV gliomas.
TAMI-31. GLIOBLASTOMA GENETIC DRIVERS DICTATE THE FUNCTION OF TUMOR-ASSOCIATED MACROPHAGES/MICROGLIA AND RESPONSES TO CSF1R INHIBITION
Authors: Rao Rohit , Han Rong , Ogurek Sean , Wu Lai Man , Zhang Liguo , Hu Jian , Garrett Matthew , Phoenix Tim , Waggoner Stephen N , Lu Qing Richard 
Published: November 2021

Abstract
Tumor-associated macrophages/microglia (TAMs) are prominent microenvironment components in human glioblastoma (GBM) that are potential targets for anti-tumor therapy. However, TAM depletion by CSF1R inhibition showed mixed results in clinical trials. We hypothesized that GBM subtype-specific tumor microenvironment convey distinct sensitivities to TAM targeting. We generated syngeneic PDGFB-driven and RAS-driven GBM models that resemble proneural-like and mesenchymal-like gliomas, and determined the effect of TAM targeting by CSF1R inhibitor PLX3397 on glioma growth and progression. We also investigated the co-targeting of TAMs and angiogenesis on PLX3397-resistant RAS-driven GBM. Using single-cell transcriptomic profiling, we further explored differences in tumor microenvironment compositions and functions between the proneural-like and mesenchymal-like glioma models. We found that the growth of PDGFB-driven tumors was markedly inhibited by PLX3397. In contrast, depletion of TAMs at the early phase accelerated RAS-driven tumor growth and had no effects on other proneural and mesenchymal human GBM models. In addition, PLX3397-resistant RAS-driven tumors did not respond to PI3K signaling inhibition. Single-cell transcriptomic profiling revealed that PDGFB-driven gliomas induced expansion and activation of pro-tumor microglia, whereas mesenchymal RAS-driven gliomas elicited TAMs enriched in pro-inflammatory and angiogenic signaling. Co-targeting of TAMs and angiogenesis decreased cell proliferation and tumor mass in RAS-driven gliomas. Our work identifies functionally distinct TAM subpopulations in the growth of different glioma subtypes. Notably, we uncover a potential responsiveness of resistant mesenchymal-like gliomas to combined anti-angiogenic therapy and CSF1R inhibition. These data highlight the importance of microenvironment landscape characterization to optimally stratify glioma patients for TAM-targeted therapy.
TAMI-33. DYNAMICS OF MICROGLIAL ACTIVATION AND EXPRESSION OF CYTOKINES IN THE SITE OF GLIOBLASTOMA TUMOR RESECTION
Authors: Ortiz-Rivera Jescelica , Kucheryavykh Lilia , Albors Alejandro 
Published: November 2021

Abstract
Glioblastoma (GBM) is the most aggressive type of brain cancer. GBM tumors are made up of a large percentage of microgliawhich support the invasive nature of tumor and the resistance to therapy. In the tumor, microglia cells can polarize into M1 and M2 phenotypes. M1 phenotype is distinguished by its ability to eliminate tumor cells, and secrete proinflammatory cytokines, whileM2 phenotype is associated with tumor cell survival and secrete anti-inflammatory cytokines. Tumor resection is one of the primary steps to treat GBM, thus, resulting in tissue damage and causing microglia activation in the surgical area. The activation state of microglia in the site of resection and the impact of microglia on glioma regrowth is unclear. The purpose of this study is to investigate the state of microglia in the tumor resection area and kinetics of microglial activation.C57BL/6/GL261 mouse glioma implantation model was used. 14 days after in-brain implantation of GL261 cells tumors were surgically resected and then re-grown tumors were analyzed at 0 hours,1, 4, 7, 14 and 21 days after tumor resection, together with the originally resected primary tumors. Microglia were purified from tumors with use of magnetic beads. Western blot analysis of microglia, purified from primary and re-grown tumors, demonstrated increase of CD86 (M1) during the first 7 days after resection and then up-regulation of Arginase (M2) in a period from 14thto 21st days after tumor resection. The cytokine expression analysis revealed significant up-regulation of Vascular Endothelial Growth Factor (VEGF) and Monocyte Chemoattractant Protein 1 (MCP1) in microglia purified from re-grown tumors. PCR analysis confirmed these data, indicating increase of VEGF, MCP1 gene expression in tumor infiltrating microglia in re-grown tumor. We can state that microglia infiltrating primary tumor and tumor re-grown after surgical resection, represent significantly different cytokines expression patterns, favorable to increased vascularization and tumor progression.
TAMI-37. STEAROYL-COA DESATURASE 1 IS ESSENTIAL FOR THE GROWTH OF IDH MUTANT GLIOMA
Authors: Yamasaki Tomohiro , Zhang Lumin , Dowdy Tyrone , Lita Adrian , Gilbert Mark , Larion Mioara 
Published: November 2021

Abstract

BACKGROUND
Increased de novo lipogenesis is a hallmark of cancer metabolism. In this study, we interrogated the role of de novo lipogenesis in IDH1 mutated glioma’s growth and identified the key enzyme, Stearoyl-CoA desaturase 1 (SCD1) that provides this growth advantage.

MATERIALS ANDMETHODS
We prepared genetically engineered glioma cell lines (U251 wild-type: U251WT and U251 IDHR132H mutant: U251RH) and normal human astrocytes (empty vector induced-NHA: NHAEV and IDHR132H mutant: NHARH). Lipid metabolic analysis was conducted by using LC-MS and Raman imaging microscopy. SCD1 expression was investigated by The Cancer Genome Atlas (TCGA) data analysis and Western-blotting method. Knock-out of SCD1 was conducted by using CRISPR/Cas9 and shRNA.

RESULTS
Previously, we showed that IDH1 mut glioma cells have increased monounsaturated fatty acids (MUFAs). TCGA data revealed IDH mut glioma shows significantly higher SCD1 mRNA expression than wild-type glioma. Our model systems of IDH1 mut (U251RH, NHARH) showed increased expression of this enzyme compared with their wild-type counterpart. Moreover, addition of D-2HG to U251WT increased SCD1 expression. Herein, we showed that inhibition of SCD1 with CAY10566 decreased relative cell number and sphere forming capacity in a dose-dependent manner. Furthermore, addition of MUFAs were able to rescue the SCD1 inhibitor induced-cell death and sphere forming capacity. Knock out of SCD1 revealed decreased cell proliferation and sphere forming ability. Decreasing lipid content from the media did not alter the growth of these cells, suggesting that glioma cells rely on de novo lipid synthesis rather than scavenging them from the microenvironment.

CONCLUSION
Overexpression of IDH mutant gene altered lipid composition in U251 cells to enrich MUFA levels and we confirmed that D-2HG caused SCD1 upregulation in U251WT. We demonstrated the glioma cell growth requires SCD1 expression and the results of the present study may provide novel insights into the role of SCD1 in IDH mut gliomas growth.
TAMI-43. HYPOXIC REGULATION OF GLIOBLASTOMA TUMOR GROWTH THROUGH L(3)MBTL1
Authors: Shih Ling-Kai , Mukherjee Subhas , Brat Daniel 
Published: November 2021

Abstract
Glioblastoma (GBM) is the deadliest and most common of all primary brain tumors. Drosophila brain tumor models have uncovered signaling pathways regulating tumor growth that are highly conserved in GBM. Our search for a novel tumor suppressor using Drosophila led to Lethal (3) malignant brain tumor [l(3)mbt], temperature-sensitive mutants of which cause neuroepithelial tumor-like overproliferation in optic lobes. dL(3)MBT and its human orthologs L3MBTL1-L3MBTL4 all harbor Malignant Brain Tumor (MBT) domains that recognize methylated lysines on histone tails. Like dL(3)MBT, hL(3)MBTL1 acts as a chromatin compaction factor that represses transcription and inhibits cytokinesis in GBM cell lines. The highly hypoxic tumor microenvironment (TME) in GBM drives its progression, recurrence, and therapeutic resistance. However, it remains unclear if L(3)MBTL1 is regulated by TME cues to promote GBM growth. Based on this knowledge gap and our preliminary data, we hypothesize that hypoxia directly regulates L(3)MBTL1 in favor of GBM growth. Analysis of TCGA data for IDH-wildtype gliomas revealed that L3MBTL1 gene expression is downregulated in GBM, which are necrotic and severely hypoxic, compared to histologic grade 2/3 gliomas, which do not contain necrosis, indicating that hypoxia could potentially suppress L3MBTL1 to enhance glioma progression. TCGA data also revealed a number of HIF pathway and hypoxia-inducible genes strongly correlating with L3MBTL1 expression, including HIF1a and VHL. Using patient-derived GBM neurosphere cultures, we exposed glioma cells to hypoxia (1% O2 for 24hrs) and found that L3MBTL1 protein levels were suppressed compared to normoxia (21%). Under these same conditions, we found more rapid cell proliferation under hypoxia. Exploration of hypoxic TME regulation of the novel tumor suppressor L3MBTL1 in glioma progression has the potential to uncover novel mechanisms involving epigenetic modulation and potentially new therapeutic strategies.
TAMI-53. CYSTEINE IS A LIMITING FACTOR FOR GLIOMA PROLIFERATION AND SURVIVAL
Authors: Rodado Victor Ruiz , Dowdy Tyrone , Jung Jinkyu , Dios-Esponera Ana , Lita Adrian , Kramp Tamalee , Camphausen Kevin , Gilbert Mark , Larion Mioara 
Published: November 2021

Abstract

BACKGROUND
Little is known about the mechanisms that render cancer cells dependent on certain nutrients from the microenvironment. Cysteine is a non-essential amino acid, since it can be synthetized from methionine through the transsulfuration pathway; moreover, cysteine is also uptake from the diet as cystine. We have investigated the metabolism of cysteine in glioma cell lines, and how cysteine/cystine-deprivation alters their antioxidant response in addition to the effect of this nutrient restriction to viability and proliferation in vitro and in vivo.

METHODS
Cysteine metabolism was investigated through LCMS-based 13C-tracing experiments and the expression levels of key enzymes in the transsulfuration pathway were also explored. Finally, a mouse model of IDH1 mutant glioma was subjected to a cysteine/cystine-free diet and tumor metabolism was analyzed by LCMS.

RESULTS
Herein, we report the dependence of glioma cells on exogenous cysteine/cystine, despite this amino acid being nonessential. Using several 13C-tracers and analysis of cystathionine synthase and cystathioninase levels, we revealed that glioma cells were not able to upregulate the transulfuration pathway cysteine, which allows methionine to be converted to cysteine in cysteine/cystine deprived conditions. We demonstrated that exogenous cysteine/cystine are crucial for glutathione synthesis, and impact growth and viability. Therefore, we explored the nutritional deprivation in a mouse model of glioma. Animals subjected to a cysteine/cystine-free diet survived longer, with concomitant reductions in glutathione and cysteine plasma levels. At the endpoint higher levels of oxidative stress were detected despite the systemic recovery of cysteine-related metabolites in the plasma.

CONCLUSION
The results presented herein reveal an alternative therapeutic approach combining cysteine/cysteine-deprivation diets and treatments involving ROS production by limiting the ability of glioma cells to quench oxidative stress through dietary interventions. Our study highlights a time window where cysteine deprivation can be exploited for additional therapeutic strategies.
TAMI-68. DECONVOLUTION OF IMMUNOTHERAPY-TREATED GLIOBLASTOMA IDENTIFIES CELLULAR HETEROGENEITY AND PLASTICITY AT THE SINGLE-CELL LEVEL
Authors: Hendriksen Josephine , Flynn Aidan , Maarup Simone , Poulsen Hans , Lassen Ulrik , Weischenfeldt Joachim 
Published: November 2021

Abstract
Glioblastoma is the most aggressive cancer originating in the brain with an average survival of 15 months. One of the characteristics of glioblastoma is the high level of intra-tumor heterogeneity (ITH), but the composition and complexity at the single-cell level is poorly understood. Here, we aimed to assess the effects and consequences of immune checkpoint inhibitor (ICI) on the cellular and molecular heterogeneity of glioblastoma tumors at the single cell level. In collaboration with the phase I trials unit at Rigshospitalet, we performed paired molecular analysis of glioma cells from primary and relapse surgery after ICI treatment. Samples were analyzed using single-cell RNA sequencing (scRNA-seq) as well as bulk RNA sequencing and whole exome DNA sequencing. In an effort to trace cellular lineages we developed and refined methods to a identify copy number changes using scRNA-seq. To this end, we identified clonal and subclonal tumor cell populations in each sample. We found high levels of ITH prior to treatment, both with respect to the glioblastoma subtype enrichment and the cell type-specific gene expression. Using expression-based cell-type classification, we found defined recurrent cell-type populations present at both surgery time points. The immune checkpoint treatment had consequences on the cellular phenotypes and proportions of tumor cells, suggesting a level of plasticity in the neoplastic cells. Moreover, we identified examples of clonal dynamics and sweeps following ICI treatment, pointing to potential treatment response and resistance in these populations. We additionally found a recurrent pattern of a small population showing high levels of cell cycle activation and simultaneously expressing markers of stem cell potential. In summary, we pursued single cell-focused analysis of ICI treated glioblastoma patients to study the cellular and molecular heterogeneity within and between glioblastoma patients, which pointed to recurrent patterns of cellular responses following ICI treatment.
TAMI-78. STEM CELL IMMUNOTHERAPY MODULATES IMMUNOREGULATORY PATHWAYS IN THE TUMOR MICROENVIRONMENT
Authors: Wildes Tyler , Dean Bayli DiVita , Dean Joseph , Font Laura Falceto , Flores Catherine 
Published: November 2021

Abstract

INTRODUCTION
A major obstacle in efficacious therapeutics against high-grade gliomas has been an inability to overcome powerful regulatory mechanisms within the TME that hamper immune activation. Fortunately, immunotherapy has enabled the enhancement of immune activation within the TME through adoptive immunotherapy and checkpoint inhibition. We found that co-transfer of hematopoietic stem cells (HSCs) with either adoptive immunotherapy or PD-1 blockade significantly improves therapeutic outcomes by manipulating the cellular components that make up the TME in high-grade gliomas. HSC co-transfer with immunotherapy leads to increased in situ downregulation of multiple immune regulatory pathways, activation of tumor-reactive T cells, and significant reduction in the frequency of MDCs and TAMs within the TME.

METHODS
C57BL/6 mice with orthotopic KR158B-gliomas received either adoptive immunotherapy using activated tumor-reactive T cells or αPD-1, either with or without HSC co-transfer. After treatment of late-stage tumors, brains were sectioned and digital spatial profiling (NanoString GeoMx) of the TME was conducted in situ. Briefly, tumor-bearing brain sections were stained for nuclei, CD3, CD45, and GFP (HSC-derived cells); regions of interest (ROIs) containing 200 nuclei were selected and processed for whole genome sequencing. Areas rich in immune cells within the TME were chosen as ROIs and compared between groups. Results were corroborated with flowcytometry and PCR.

RESULTS
Mice that received HSCs with either adoptive cellular therapy or αPD-1 had reductions in expression of multiple regulatory markers in the TME including iNOS, TGFβ, and PD-L1. This was accompanied by reductions in the frequencies of MDSCs and TAMs. An increased relative abundance of activated CD8+ T cells within the TME was also observed. Interestingly, we found that HSC-derived cells provided rich amounts of dendritic cells at the TME when co-transferred with immunotherapy. Host-derived myeloid cells were significantly displaced from the TME in mice receiving HSC plus adoptive cellular therapy or αPD-1.
TMOD-15. CHARACTERIZATION OF THE MINIMAL RESIDUAL DISEASE STATE REVEALS DISTINCT EVOLUTIONARY TRAJECTORIES OF HUMAN GLIOBLASTOMA
Authors: Qazi Maleeha , Salim Sabra , Brown Kevin R , Savage Neil , Mickolajewicz Nicholas , Han Hong , Chokshi Chirayu R , Mansouri Alireza , Venugopal Chitra , Kislinger Thomas , Goyal Sidhartha , Moffat Jason , Singh Sheila K 
Published: November 2021

Abstract
Recurrence of solid tumors renders patients vulnerable to a distinctly advanced, highly treatment-refractory disease state that has an increased mutational burden and novel oncogenic drivers not detected at initial diagnosis. Improving outcomes for recurrent cancers requires a better understanding of cancer cell populations that expand from the post-therapy, minimal residual disease (MRD) state. We profiled barcoded tumor cell populations through therapy at tumor initiation/engraftment, MRD and recurrence in our therapy-adapted, patient-derived xenograft models of glioblastoma (GBM). Tumors showed distinct patterns of recurrence in which clonal populations exhibited either a priori, pre-existing fitness, or equipotent fitness acquired through therapy. Characterization of the MRD state by single-cell and bulk RNA sequencing revealed a tumor-intrinsic immunomodulatory signature with strong prognostic significance at the transcriptomic level and in proteomic analysis of cerebrospinal fluid (CSF) collected from GBM patients at all stages of disease. Our results provide insight into the innate and therapy-driven dynamics of human glioblastoma, and the prognostic value of the interrogating of the MRD state in solid cancers.
TMOD-20. CASE REPORT: THE ODYSSEY TO THE RIGHT DIAGNOSIS. SURPRISING GLIOBLASTOMA MIMICS
Authors: Dorin Patrick , Jochum Wolfgang , Lauber Arno , Neidert Marian Christoph , Hundsberger Thomas 
Published: November 2021

Abstract
A 57-year-old female presented at the emergency room with acute onset aphasia but unremarkable cCT (incl. angiography and perfusion). Suspecting an ischemic stroke, she received thrombolysis with quick recovery of aphasia. Afterwards, myoclonic jerks of the face and right arm occurred leading to anticonvulsant therapy. Follow-up cMRI surprisingly demonstrated swollen T2w-hyperintense and Gd-enhancing left limbic, temporal and frontal lobes. Suspected herpes-simplex-encephalitis was treated with aciclovir despite unremarkable CSF results (no pleocytosis, no BBB disruption, negative HSV-PCR) on day 2 and follow-up (day 5). Due to persisting cognitive deficits, autoimmune limbic encephalitis was suspected, and intravenous immunoglobulin therapy was added. Three weeks later, she experienced new neurological symptoms (weakness, blurred vision, vomiting, headache). Follow-up brain MRI demonstrated a massive increase of multifocal Gd-enhancing lesions. Partial resection revealed the diagnosis of an IDH-wildtype glioblastoma (GB). Next generation oncogene panel testing demonstrated a GOPC-ROS1 fusion which is rarely found in GB. Due to the gliomatosis-like infiltration of both hemispheres, radiotherapy was deemed to be too toxic. Instead, she received two cycles of lomustine in absence of a MGMT-promotor methylation. Two months later cMRI showed a symptomatic second multilocular progression. 2nd-line therapy with a ROS-inhibitor was rejected, whereupon she died five weeks later. Our case is in several aspects peculiar: It demonstrates that rare GB-mimics (i.e. HSV- and autoimmune limbic encephalitis) can only be ruled out in a fast manner by brain biopsy. Watchful waiting may neglect fast progression of GB leading to the inability to provide optimal treatment (i.e. radiotherapy). Thrombolysis is strictly contraindicated in primary brain tumors, but was unharmful in our case most probably to the early tumor stage without relevant neoangiogenesis. Rare genetic abnormalities like ROS1-fusions which are reported mostly in childhood glioblastoma may be present and serve as a therapeutic target also in adult GB.