bluuebunny/crossref_metadata_2025_split huggingface dataset:
TAMI-50. CHITINASE-3-LIKE-1 PROTEIN BINDING COMPLEXES REGULATE IMMUNE SUPPRESSION IN GLIOBLASTOMA
Authors: Chen Apeng , Jiang Yinan , Li Zhengwei , Zou Han , Santiago Ulises , Xiao Xiangwei , Camacho Carlos , Pollack Ian , Hu Baoli 
Published: December 2020

Abstract
Glioblastoma (GBM), the most common and lethal brain tumor, remains incurable despite intensive multimodal treatment. While immunotherapies have been highly effective in some types of cancer, the disappointing results from clinical trials for GBM immunotherapy represent continued challenges. GBM is highly immunosuppressive and resistant to immunotherapy because of glioma cells escaping from immune surveillance by reprograming the tumor microenvironment (TME). However, understanding the mechanisms of immune evasion by GBM remains elusive. Here, we found that Chitinase-3-like-1 (CHI3L1) is highly expressed in GBM and associated with a poor clinical outcome. CHI3L1, also known as human homolog YKL-40, plays a role in tissue remodeling, inflammation and cancer. Interestingly, we found that genetic knockdown (KD) of Chi3l1 in syngeneic immunocompetent mouse GBM models resulted in increased tumor-infiltrating lymphocytes, tumor size reduction, and improved animal survival. Surprisingly, the parallel loss-of-function experiment revealed that Chi3l1 KD did not repress tumor progression in the orthotopic immunodeficient mice with deficient T and B cells. These results suggest the predominant role of CHI3L1 in regulating the GBM immune TME, rather than in tumor cells per se. Mechanistically, we discovered that Galectin-3 (Gal-3) and Galectin-3 binding protein (Gal-3BP) interact competitively with the same binding motif on CHI3L1, leading to selective migration of protumor M2-like versus antitumor M1-like bone marrow-derived macrophages (BMDMs) and resident microglia (MG). Transcriptomic analysis revealed that pro-inflammatory signature and T cell mediated immunity and cytotoxicity signaling are significantly enriched in tumor associated macrophages/microglia (TAMs) composed of BMDMs and MG, which were isolated from tumors with Chi3l1 KD versus wild type. In vitro validations suggest that CHI3L1-Gal-3, but not CHI3L1-Gal-3BP protein binding complex, activates PI3K/AKT/mTOR signaling to control the TAM switch of immune suppression and immune stimulation. Together, these results shed light on molecular mechanism of GBM immune evasion and potential new immunotherapeutic strategies for GBM treatment.
TAMI-54. THE PRESENCE OF IMMUNE CELL INFILTRATES IN THE TISSUE MICROENVIRONMENT OF HIGH-GRADE GLIOMAS AND THEIR ASSOCIATION WITH OVERALL SURVIVAL
Authors: Rishi Anupam , Mohammadi Homan , Martir Daniela , Welsh Eric , Robinson Timothy , Oliver Daniel , Eschrich Steven , Torres-Roca Javier , Yu Hsiang-Hsuan , Grass George , Ahmed Kamran 
Published: December 2020

Abstract

OBJECTIVE
Tumor-associated microglia and macrophages (TAMs) influence brain tumor biology and promote tumor-proliferating phenotype. Studies have shown these cell types predict outcomes in various tumor sites with limited evidence in high-grade gliomas (HGG). In this study, we assessed the presence of immune cell infiltrate (ICI) and overall survival (OS) in HGGs.

METHODS
A total of 97 consecutively treated patients with primary HGG with complete gene expression profiling were identified from our IRB-approved institutional tissue biorepository. Patients underwent primary surgical resection between 02/2004 and 03/2011. Gene expression levels were assessed by Affymetrix Hu-RSTA assays (Affymetrix; Santa Clara, CA). CIBERSORT estimated the presence of ICI via gene expression deconvolution. Tumor characteristics and the presence of 22 individual ICI subtypes were assessed with respect to OS. Time-to-event analyses were performed with Kaplan-Meier estimates and compared via log-rank test. Associations between the ICI and outcomes were explored using Cox-regression. P&lt; 0.05 (two-tailed) was considered statistically significant.

RESULTS
Median follow-up from primary surgical resection was 12.8 months (range: 0.1-162.8), and median age was 58 years (20-85). Most patients were male (n=63; 65%) and had grade 4 tumors (n=71; 73%). OS differed by grade with 24-month actuarial OS rates of 81% and 34% (P&lt; 0.0001) for grade 3 and 4 gliomas, respectively. The presence of M0 (HR 2.2; 95% CI 1.4-3.6; P=0.001), M1 (HR 1.8; 95%CI 1.1-2.9; P=0.01), and M2 macrophages (HR 1.9; 95%CI 1.2-3.2; P=0.007) predicted OS. No other ICI subtypes were predictive of OS. The presence of M0- and M2-polarized macrophages were more common in grade 4 compared to grade 3 gliomas 46% vs. 11% (P=0.002) and 69% vs. 31% (P=0.0007), respectively.

CONCLUSION
The increased presence of non-polarized or M2 TAMs within the glioma microenvironment was significantly associated with OS in HGG. Their presence may serve as unique stratification and a potential therapeutic target.
TAMI-59. METABOLIC REGULATION OF THE EPIGENOME DRIVES LETHAL INFANTILE EPENDYMOMA
Authors: Michealraj Antony , Kumar Sachin , Kim Leo , Rich Jeremy , Taylor Michael 
Published: December 2020

Abstract
Ependymomas are malignant glial tumors that occur throughout the central nervous system. Of the nine distinct molecular types of ependymoma, Posterior Fossa A(PFA) ependymomas, found in the hindbrain of infants and young children, are the most prevalent type. They rarely harbor recurrent somatic single nucleotide or copy number aberrations, but rather display epigenetic dysregulations. Transcriptional analyses show that PFAs, but not other molecular ependymoma variants, have elevated hypoxic signaling. We hypothesized that the metabolic environment of the developing human fetal hindbrain contributes to PFA ependymomas through the intermediary metabolic mechanism. Hypoxia microenvironment is essential for PFA survival and upholding their epigenetic dysregulation. Hypoxia blocks methyltransferase activity by upregulating EZHIPs expression and restricting SAM abundance. Fine-tuning the abundance of a-KG and acetyl-CoA, hypoxia fuels demethylase, and acetyltransferase activity which collectively resulting in H3K27 hypomethylation and hyperacetylation. Genome-wide essentially screen further underscore that minimal basal level of H3K27me3 is essential for PFA survival and further attenuation of H3K27me3 decreases the fitness of PFAs. PFA Ependymomas have a unique epigenome, suggesting a model in which they thrive in a narrow Goldilocks zone, with deviation to either increased or decreased H3K27me3 levels leading to diminished cellular fitness. PFAs are maintained under hypoxia, associated with restricted availability of specific metabolites to diminish histone methylation and increase histone demethylation and acetylation at H3K27. PFAs initiate from a cell lineage in the first trimester of human development that resides in restricted oxygen. Unlike other ependymomas, transient exposure of PFA cells to ambient oxygen induces irreversible cellular toxicity. PFA tumors exhibit a low basal level of H3K27me3 and, paradoxically, inhibition of H3K27 methylation specifically disrupts PFA growth. Microenvironmental regulation of PFA ependymoma epigenome appears to play a major role in tumorigenesis. Targeting metabolism and/or the epigenome presents a unique opportunity for rational therapy for infants with PFA ependymoma.
TMOD-01. DEVELOPING CLINICALLY RELEVANT BRAIN METASTATIC TUMOR MODELS FOR TARGETED STEM CELL THERAPEUTICS
Authors: Kitamura Yohei , Moleirinho Susana , Kanaya Nobuhiko , Franco Arnaldo , Shah Khalid 
Published: December 2020

Abstract
Brain metastasis is associated with increased mortality in patients with cancer, 15-20% of patients will develop brain metastasis during the course of the disease. Characterizing clinically relevant brain metastasis models and exploring different options to deliver drugs across blood brain barrier in such models are fundamental for the development of novel therapies for metastatic brain tumors. We have created imageable breast to brain metastasis tumor models using patient derived brain seeking basal like breast cancer (BLBC) lines. We show a widespread distribution of micro- and macro-metastasis and the close association of tumor cells with blood vessels in the brain thus mimicking the multi-foci metastases observed in the clinics. These models enables us to investigate the pathophysiology of this little-known phenomenon and test the efficacy of new approach targeting the dormant cancer cells in perivascular niche. Next, we assessed the EGFR and DR4/5 levels in BLBC and show that brain seeking BLBC have higher EGFR and DR5 levels than their primary counterparts. We also show that intracarotid artery injection or intrathecal injection of stem cells engineered to express optical imaging markers home to metastatic brain tumors. These findings provide useful models for testing treatments for metastatic brain tumors and also provide insights into the changes in gene expression in metastatic BLBC and means to deliver therapeutics to metastatic tumors in the brain.
TMOD-02. IN VITRO & IN VIVO CULTURE OF PATIENT DERIVED (PD) CSF-CTCS IN LEPTOMENINGEAL DISEASE (LMD) FROM MELANOMA TO IDENTIFY NOVEL TREATMENT STRATEGIES
Authors: Law Vincent , Evernden Brittany , Puskas John , Caceres Gisela , Ryzhova Elena , Smalley Inna , Tran Nam , Etame Arnold , Magliocco Anthony , Smalley Keiran , Forsyth Peter 
Published: December 2020

Abstract

BACKGROUND
Approx. 5% of melanoma pts develop LMD. There are essentially no models of LMD available for therapeutic development. A significant barrier to the development of effective therapies against LMD has been the inability to culture and expand LMD cells. Here we report our strategies to in vitro & in vivo culturing of CSF-CTCs. As a proof of concept, we assessed response to Ceritinib (Cer), a non-canonical IGF1R inhibitor) in combination with MEK inhibitor.

METHODS
We collected CSF from 11 patients (pts) from various sources (ie: LPs, Ommayas, autopsies). 3 pts CSF were collected at autopsies. PD-CSF-CTCs were expanded in vitro in conditioned media and in vivo using CDX model. scRNAseq analysis was performed to assess expression profiles of PD-CSF-CTCs.

RESULTS AND DISCUSSION
Of the total 61 PD-CSF-CTCs collected from 11 pts (avg: 4.07 CSF collections/patient), we successfully cultured PD-CSF-CTCs from 3 pts (20%) and were able to grow them in vivo from 2 pts (18%). scRNAseq analysis identified MLANA, IGF1R, SOX9 and ErbB3 were among genes highly expressed in our PD-CSF-CTCs. We evaluated the responses of the combination Cer with MEKi (Tra) in vitro and in vivo and found that these agents produced therapeutic effects to both established melanoma cell lines and our PD-CSF-CTCs. For example, in vivo testing showed a median survival (MS): 18, 35, and 27 days in WM164, WM164R and the PD-CSF-CTCs, respectively, in control groups. Whereas treatment with Cer + Tra produced significantly better MS in all three in vivo models and was not reached in WM164, WM164R (p&lt; 0.001 & p&lt; 0.047, respectively) and 38.5 days in PD-CSF-CTCs (p&lt; 0.032).

CONCLUSIONS
Though the sample size is small, this is the first report of the successful in vitro & in vivo culture of CSF-CTCs from pts with LMD.
TMOD-03. PAN-CANCER ANALYSIS OF ORTHOTOPIC PATIENT DERIVED XENOGRAFTS FROM BRAIN METASTASES
Authors: Zeng Yu , Pelton Kristine , Yerrum Smitha , Kao Pei-Lun , Sinai Claire , Tran Tony , Sinha Rileen , Shetty Aniket , Tolstorukov Michael , Jaber Aliya , Freitas Dylan , Pisano William , Verselis Sigitas J , Herbert Zach T , Lin Nancy , Zhao Jean J , Weinstock David M , Chukwueke Ugonma , Aizer Ayal A , Chiocca E Antonio , Bi Wenya Linda , Wen Patrick , Lee Eudocia , Nayak Lakshmi , Meredith David , Santagata Sandro , Chow Kin Hoe , Ligon Keith 
Published: December 2020

Abstract
Brain metastases (BM) are a leading cause of cancer death and prognosis remains poor despite treatment advances at other sites. Models are central to therapeutic development, but few orthotopic patient-derived xenograft (PDX) models of BM exist. To represent diversity across BM types, we established a program to create orthotopic PDX at scale from all BM patients. To date BM were received from 100 patients and PDX attempted by direct brain injection (PDX, n=89) or injection of low passage patient-derived cell lines (PDCLX, n=11). We created 65 successful BM PDX from 13 cancers: 17 lung (55% take), 15 breast (68%), 6 melanoma (75%), 5 CNS lymphoma (83%), 3 gastrointestinal (75%), 2 esophageal (40%), 2 ovarian (67%), 1 sarcoma (100%), 1 laryngeal (100%), 1 prostate (100%), 1 pancreatic (100%), 1 uterine adenosarcoma (100%), and 1 yolk sac tumor (100%). Take rate was similar for models derived from patients with prior chemotherapy-only versus immune/targeted therapy-only (63 vs 58%). Fifteen patients had live tumor and matching PBMCs archived for modeling in vitro immunotherapy responses. Mean time to moribund among different cancer types ranged from 27 days (yolk sac tumor) to 177.5 days (ovarian). BM PDX had a favorable timeline for preclinical study (90% moribund at 180 days). All PDX retained high fidelity to the patient driver SNVs and copy aberrations, even at &gt;P4. No significant differences noted by immunodeficient strain (SCID versus NSG) or injection site (orthotopic versus heterotopic). Explants from BM PDX were able to generate long-term cell lines (60%) or short-term cultures with qualitative concordance of model-to-patient responses to targeted therapy (Osimertinib, EGFRi) and immunotherapy (Pembrolizumab, PD1i). Genomic and clinical data were used to create the DFCI BM PDX cBioPortal for public release and models distribution will be available through the DFCI Center for Patient Derived Models.
TMOD-12. ESTABLISHING A CLINICALLY RELEVANT MODEL OF MESENCHYMAL GLIOBLASTOMA (GBM) TO STUDY RESPONSE TO STANDARD OF CARE TREATMENT AND IMMUNE CHECKPOINT INHIBITION (ICI).
Authors: Clerkin James , Connor Kate , Sweeney Kieron , White Kieron , Shiels Liam , Maher Stephen , Marignol Laure , Prehn Jochen H M , O’Brien David , Byrne Annette 
Published: December 2020

Abstract
GBM is a devastating disease with peak incidence in the seventh decade. Pre-clinical models are essential for studying resistance mechanisms and screening novel therapies. However, historically these models have failed to predict response in humans. Current models seldom incorporate surgical resection, and commonly use young animals whose immune contexture differs from older patients. Here, we have established an orthotopic model employing the syngeneic mesenchymal-NFpp10a-cell line which incorporates surgical resection in aged mice. We further characterise response to ICI and temozolomide monotherapy. NFpp10a and GL261-cell lines were exposed in vitro to irradiation (0Gy/2Gy/5Gy) and response assessed using colony formation assays. NFpp10a formed significantly more colonies at 5Gy compared to GL261 at both day 10 (NFpp10a 5.167 vs GL261 1.4; p=0.0017) and day 14 (NFpp10a 3.5 vs GL261 0; p&lt; 0.0001). Hence, NFpp10a displays increased radioresistance. Next, NFpp10a-luciferin expressing cells were orthotopically implanted into young (6-8weeks;n=16) and aged (18months;n=16) C57BL/6-mice. Weekly bioluminescence imaging (BLI) was performed to monitor growth. Mice undergoing resection showed a median 18.47-fold drop in BLI signal. We demonstrated resection survival advantage in aged mice (Resection:33.5 days vs Non-Resection:18 days, p= 0.0166) and showed young age to be a positive prognostic factor (Young:62 days vs Aged:22 days, p=0.0002). Subsequently, we orthotopically implanted NFpp10a-Luc2 cells into C57BL/6 mice and treated with temozolomide (n=24) or PBS control (n=23), and anti-PD1 (n=24) or IgG (n=23). We observed that temozolomide and anti-PD1 monotherapy had no impact on NFpp10-Luc2 growth (temozolomide-overall:p=0.9001, anti-PD1-overall:p=0.7933) or survival (temozolomide-overall:p=0.3035, anti-PD1-overall:p=0.6328). Overall, we have established an NFpp10-Luc2 mesenchymal-GBM model in aged mice which incorporates surgical resection and accurately displays significant resistance to temozolomide and anti-PD1 monotherapy. We are currently employing this model to study the efficacy of neoadjuvant anti-PD1 therapy. Mechanistic analyses with multiplex-immunohistochemistry, scRNA and whole exome sequencing are planned to interrogate treatment effects on the tumor microenvironment.
TMOD-34. PATIENT-DERIVED XENOGRAFT AND CELL LINE MODELS FACILITATE NOVEL TREATMENT DISCOVERY IN CENTRAL NERVOUS SYSTEM LYMPHOMAS
Authors: Meredith David , Chow Kin Hoe , Kao Pei-Lun , Zeng Yu , Sinha Rileen , Shetty Aniket , Tolstorukov Michael , Tran Tony , Yerrum Smitha , Chukwueke Ugonma , Bi Wenya Linda , Arnaout Omar , Smith Timothy , Ligon Keith , Nayak Lakshmi 
Published: December 2020

Abstract
Lymphomas of the central nervous system (CNSL) are rare tumors with few treatment options; however, recent genomic studies have uncovered several druggable targets. To facilitate novel treatment discovery, we sought to establish patient-derived xenograft (PDX) models and cell lines from patients with newly diagnosed or recurrent CNSL. PDX models were attempted from fresh tumor samples from 18 consented patients for whom rich clinical annotation was available. Orthotopic intracranial injections were performed via stereotactic injection. Cell line generation was attempted from both primary tumors (PDCL) and PDX samples (PDXCL). Characterization included histopathology, targeted exome sequencing, low-pass whole-genome sequencing for copy number evaluation, and expression profiling of matched patient tumors and PDXs. Drug response testing was performed using CellTiterGlo. From 18 samples attempted, 8 PDX models were successfully generated: 2 primary CNS diffuse large B-cell lymphoma (DLBCL), 5 secondary CNS DLBCL, and 1 secondary cutaneous T-cell lymphoma (CTCL). Mean time to moribund was 66 days. All 8 PDXs grew successfully as orthotopic models, and 4 also grew in subrenal capsule. Additionally, 6 PDCL and 2 PDXCL were established (&gt; P3). Models faithfully represented primaries, showing nearly identical histopathology, immunoprofiles, and genomic signatures. To support expanded and rapid preclinical use of these models in drug testing we documented that PDX could be explanted to create short-term cell preparations or long-term cell lines with a 100% and 40% success rate, respectively. Proof of principle testing showed that explanted DLBCL PDX cells and cell lines showed sensitivity to copanlisib and venetoclax, which were not efficacious in the CTCL PDX. These findings showcase a diverse collection of CNSL models demonstrating high fidelity to primary tumors at the genomic and phenotypic levels, emphasizing their utility for preclinical studies and as patient avatars to rapidly determine sensitivities to existing and novel regimens prior to initiation of therapy.
TMOD-35. DEVELOPING RECURRENT GBM PDX, IN VIVO, FROM TREATMENT NAÏVE SOURCES
Authors: James Charles , Cheng Shi-Yuan , Horbinski Craig , Sarkaria Jann , Stupp Roger , Ahmed Atique 
Published: December 2020

Abstract

PURPOSE
Post-therapy recurrent glioblastoma (GBM) patient-derived xenografts (PDX), developed from corresponding treatment-naïve PDX, could serve as useful resources for identifying therapeutics with activity against recurrent GBM. The goal of this study was to determine whether treatment-naïve intracranial GBM PDX, in mice receiving radiotherapy (RT) and/or temozolomide (TMZ), acquire the same mutations that occur in post-RT+TMZ GBMs from patients.

METHODS
Luciferase-modified, treatment-naïve GBM PDX were engrafted in the brains of athymic nude mice, followed by treatment with RT only (2 Gy/day x 5), TMZ only (10 mg/kg/day x 5), or RT+TMZ. Bioluminescence imaging was used to monitor intracranial tumor growth, response to treatment, and recurrence from treatment. Some mice with recurrent tumors received additional TMZ treatment. When mice became symptomatic, intracranial tumors were resected and engrafted subcutaneously in a new mouse host, then sequentially propagated subcutaneously into additional host mice. After the third passage, whole-exome sequencing (WES) was done, comparing post-therapy with treatment-naïve PDX sequence variants.

RESULTS
Analysis of PDX WES showed the following: 1) TMZ consistently caused more genes to incur coding sequence mutations than RT, as much as 13x more; 2) TMZ-treated tumor mutations were mostly G-C to A-T transitions (71-92%), consistent with the known mutagenic effect of TMZ; and 3) post-therapy PDX acquire similar mutations as do recurrent GBMs in patients, for example involving DNA mismatch repair gene MSH6. One of the derivative PDX with MSH6 mutation has been retested for response to RT and TMZ, with results showing its having become TMZ, but not RT resistant.

CONCLUSIONS
The mutation profiles of RT+TMZ-treated PDX are similar to those reported for GBMs that recur after RT+TMZ in patients. The new PDX resources described here may prove useful for identifying effective treatments against recurrent GBM.
ATRT-01. UPREGULATION OF PROTEIN SYNTHESIS AND PROTEASOME DEGRADATION CONFERS SENSITIVITY TO PROTEASOME INHIBITOR BORTEZOMIB IN MYC-ATYPICAL TERATOID/RHABDOID TUMORS
Authors: Tran Minh-Huy , Wu Kuo-Sheng , Chang Che-Chang , Wong Tai-Tong 
Published: December 2020

Abstract

BACKGROUND
Atypical teratoid rhabdoid tumors (ATRTs) are among the most malignant brain tumors in early childhood and remain incurable. Myc-ATRT is driven by the Myc oncogene, which directly controls the intracellular protein synthesis rate. Proteasome inhibitor bortezomib (BTZ) was approved by the Food and Drug Administration as a primary treatment for multiple myeloma. This study aimed to determine whether the upregulation of protein synthesis and proteasome degradation in Myc-ATRTs increases tumor cell sensitivity to BTZ.

METHODS
We performed differential gene expression and gene set enrichment analysis on matched primary and recurrent patient-derived xenograft (PDX) samples from an infant with ATRT. The expressions of proteasome-encoding genes were compared among this paired model as well as between the 24 human ATRT samples and normal brain tissues. The antitumor effect of BTZ was evaluated in three human Myc-ATRT cell lines (PDX-derived tumor cell line Re1-P6, BT-12, and CHLA-266) and in the orthotopic xenograft models of Re1-P6 cell.

RESULTS
Concomitant upregulation of the Myc pathway, protein synthesis, and proteasome degradation were identified in recurrent ATRTs. In ATRTs, the proteasome-encoding genes were highly expressed compared with in normal brain tissues, correlated with the malignancy of tumor cells, and were essential for tumor cell survival. BTZ inhibited proliferation and induced apoptosis through the accumulation of p53 in in vitro drug tests. Furthermore, BTZ inhibited tumor growth and prolonged survival in Myc-ATRT orthotopic xenograft mice.

CONCLUSIONS
Our findings suggest that BTZ may be a promising targeted therapy for Myc-ATRTs.