bluuebunny/crossref_metadata_2025_split huggingface dataset:
IMMU-04. IMMUNE-RELATED ADVERSE EVENTS STRONGLY PREDICT SUPERIOR OUTCOMES IN BRAIN METASTASES PATIENTS RECEIVING LOCAL TREATMENT AND IMMUNE CHECKPOINT INHIBITORS
Authors: Hulsbergen Alexander , Lak Asad , Lo Yu Tung , Lamba Nayan , Nagtegaal Steven , Job Arun , Verhoeff Joost , Smith Timothy , Broekman Marike , Phillips John 
Published: December 2020

Abstract

INTRODUCTION
In several cancers treated with immune checkpoint inhibitors (ICIs), a remarkable association between the occurrence of immune-related adverse events (irAEs) and superior oncological outcomes has been reported. This effect has hitherto not been reported in the brain. This study aimed to investigate the relation between irAEs and outcomes in brain metastases (BM) patients treated with both local treatment to the brain (LT; i.e. surgery and/or radiation) and ICIs.

METHODS
This study is a retrospective cohort analysis of patients treated for non-small cell lung cancer (NSCLC) BMs in a tertiary institution in Boston, MA. Outcomes of interest were overall survival (OS) and intracranial progression-free survival (IC-PFS), measured from the time of LT. Sensitivity analyses were performed to account for immortal time bias (i.e., patients who live longer receive more cycles of ICIs and thus have more opportunity to develop an irAE).

RESULTS
A total of 184 patients were included; 62 (33.7%) were treated with neurosurgical resection and 122 (66.3%) with upfront brain radiation. irAEs occurred in 62 patients (33.7%). After adjusting for lung-Graded Prognostic Assessment, type of LT, type of ICI, newly diagnosed vs. recurrent BM, BM size and number, targetable mutations, and smoking status, irAEs were strongly associated with better OS (HR 0.33, 95% CI 0.19 – 0.58, p &lt; 0.0001) and IC-PFS (HR 0.41; 95% CI 0.26 – 0.65; p = 0.0001). Landmark analysis including only patients who received more than 3 cycles of ICI (n = 133) demonstrated similar results for OS and IC-PFS, as did sensitivity analysis adjusting for the number of cycles administered (HR range 0.36 – 0.51, all p-values &lt; 0.02).

CONCLUSIONS
After adjusting for known prognostic factors, irAEs strongly predict superior outcomes after LT in NSCLC BM patients. Sensitivity analysis suggests that this is unlikely due to immortal time bias.
IMMU-05. CSF METABOLOMICS AS A PREDICTOR OF SURVIVAL IN PATIENTS WITH BRAIN METASTASIS RECEIVING IMMUNOTHERAPY
Authors: Sarangi Sasmit , Zhang Devin , Dong Anita , Lok Edwin , Wong Eric 
Published: December 2020

Abstract

INTRODUCTION
Checkpoint inhibitors show a positive intracranial response in around 20–50% of patients with metastatic melanoma and non-small cell lung cancer (NSCLC). There is a current paucity of biomarkers to prospectively identify these patients. We hypothesize that CSF would provide useful data on tumor-related metabolites to help stratify responders and non-responders. We focused on adenosine and related nucleotides based on their role in creating an immunosuppressive tumor microenvironment.

METHODS
Fifty-one patients (43 with melanoma and 8 with NSCLC) received immunotherapies. The CSF samples from this cohort were compared to 30 controls and 60 non-immunotherapy-treated patients (13 with melanoma and 47 with NSCLC) using liquid chromatography/tandem mass spectrometry for quantitative assessment of metabolites.

RESULTS
The age and sex distribution were comparable in both cohorts. The most common immunotherapy regimens were ipilimumab, α-interferon and IL-2, while the most common non-immunotherapy regimens were carboplatin/taxol, carboplatin/pemetrexed and pemetrexed alone. CSF AMP, but not adenosine, ADP or ATP, from the immunotherapy cohort was higher in comparison to the non-immunotherapy cohort (P=0.0495). An adenosine/AMP ratio (AAR) was used to quantify relative adenosine production from AMP. AAR of 3.5–7 was associated with lower median survival from diagnosis of brain metastasis in immunotherapy-treated patients (9.1 months, log-rank P=0.0197). AAR below or above this range had significantly higher median survival (27.7 and 24.2 months, respectively). The same AARs could not stratify for survival in non-immunotherapy-treated patients (log-rank P=0.3039). Compared to the non-immunotherapy cohort, the immunotherapy cohort had higher kynurenine, glyceraldehyde 3-phosphate, pyruvate and lactate, as well as succinate, fumarate, malate, oxaloacetate, aconitate and isocitrate (all P&lt; 0.05).

CONCLUSION
AAR of 3.5–7 could indicate an immunosuppressive microenvironment and needs further investigation to identify immunotherapy non-responders. The presence of elevated kynurenine, succinate, fumarate, malate and oxaloacetate suggests glutaminolysis related to immunotherapy. Research supported by the 2019 AACR-Bayer Innovation and Discovery Grant.
IMMU-06. DISCERNING THE DIFFERENT BONE MARROW IMMUNE LANDSCAPES
Authors: Strong Michael , Ahmed Aqila , Calinescu Anda-Alexandra , Zhou Xiaofeng , Robinson Tyler , Rocco Sabrina , Siegel Geoffrey , Clines Gregory , Moore Bethany , Keller Evan , Szerlip Nicholas 
Published: December 2020

Abstract
Roughly 400,000 people have bone metastases in the U.S. with the vast majority of these occurring in the spine. The etiology of bone metastasis still remains to be fully elucidated. This study explored the differences in immune landscape between long bone and spine that may contribute to higher rates of bone metastasis to the spine. Spines and femurs from male C57BL6/J mice (N=10) were processed for flow cytometry and immunophenotyping using Mass Cytometry by Time-Of-Flight (CyTOF). The cells were analyzed with CyTOF using a 33-surface protein marker mouse antibody panel. Spines (N=3) and femurs (N=2) from patients were analyzed with CyTOF using the Maxpar Complete Human T cell Immuno-Oncology Panel Set. There are global differences in the immune cell composition between the long bone and spine microenvironment. Flow cytometry revealed slight increases in the CD45+ and Cd11b+ cell populations in the bone marrow of murine spines compared to murine long bone, which are markers for myeloid-derived suppressor cells (MDSCs). Using CyTOF, significant differences in the immune cell landscape between long bone and spine were observed. In the murine long bone, an increase in monocytes/macrophages, myeloid progenitors, granulocytic MDSCs, granulocytes, and mast cells was observed compared to the spine. In the murine spine an elevation of CD8a+ DC cells, classical monocytes, MDSCs, pDCs, memory T helper cells, and NK T cells was seen. Evaluation of human long bone and spine revealed similar trends with a predominance of myeloid progenitor cells and monocytes in the human vertebra compared to the human long bone marrow. Significant differences in the immune microenvironment exist between the spine and long bone marrow in both murine and human samples. This is the first report of significant differences in immune cell populations between different skeletal locations. However, the functional significance of these differences has yet to be determined.
IMMU-08. MODELING UPFRONT GLIOBLASTOMA SURGICAL RESECTION AND STEROID USE REVEALS IMMUNOSUPPRESSIVE CHANGES AND SUGGESTS THAT PERIPHERAL LYMPHOCYTE COUNTS ARE ASSOCIATED WITH TUMOR VOLUME AND PROGNOSIS
Authors: Otvos Balint , Alban Tyler , Grabowski Matthew , Bayik Defne , Winkelman Robert , Johnson Sarah , Rabljenovic Anja , Vogelbaum Michael , Ahluwalia Manmeet , Fecci Peter , Lathia Justin 
Published: December 2020

Abstract
Glioblastoma (GBM) and its treatment produces systemic immunosuppression, which is being targeted by immunotherapies. However, it remains unclear how surgical resection and steroids specifically in GBM alter the immune system. To further explore this issue, immunocompetent C57Bl/6 mice were intracranially inoculated with syngeneic glioma cells (GL261 and CT-2A) and growth of tumors was evaluated by MRI. Host immune cell populations were analyzed during surgical resection and steroid administration. Mice with surgically resected tumors had a longer median survival compared to mice subjected to tumor biopsies, and had increased bone marrow sequestration of both CD4 and CD8 T cells with corresponding decreased blood lymphocytes. Furthermore, physiologic doses of dexamethasone administered perioperatively decreased tumor edema, but increased the number and proliferative capacity of both marrow and circulating MDSCs while generating no survival benefit. Independent of therapy or dexamethasone, intracranial tumor volume correlated linearly with decreased CD4 and CD8 T cells in peripheral blood, and increased T cell sequestration within the bone marrow. We validated these parameters in steroid-naïve newly diagnosed GBM patients and observed decreased lymphocytes correlated linearly with increased tumor volume. When initial lymphocyte counts in both steroid-naïve and steroid-administered patients were used in univariate and multivariate models predicting progression-free survival and overall survival, decreased initial lymphocyte counts were an independent predictor of decreased progression free survival and decreased overall survival, with steroid use and initial tumor size falling out of significance during stepwise selection. Taken together, tumor volume is linearly correlated with marrow sequestration of lymphoid cells, but both surgery and steroid administration further suppress active immune responses along lymphoid and myeloid lineages. Furthermore, decreasing peripheral lymphocyte counts at diagnosis of GBM indicate an immune system less able to mount responses to the tumor and portent a worse progression free and overall survival.
IMMU-09. CONCURRENT DEXAMETHASONE LIMITS THE CLINICAL BENEFIT OF IMMUNE CHECKPOINT BLOCKADE IN GLIOBLASTOMA
Authors: Iorgulescu Bryan , Gokhale Prafulla , Speranza Maria , Eschle Benjamin , Poitras Michael , Wilkens Margaret , Soroko Kara , Chhoeu Chhayheng , Knott Aine , Gao Yang , Lim-Fat Mary Jane , Baker Gregory , Bonal Dennis , Nguyen Quang-De , Grant Gareth , Ligon Keith , Sorger Peter , Chiocca E Antonio , Anderson Ana , Kirschmeier Paul , Sharpe Arlene , Freeman Gordon , Reardon David 
Published: December 2020

Abstract

BACKGROUND
Dexamethasone, a uniquely potent corticosteroid, is frequently administered to brain tumor patients to decrease tumor-associated edema, but limited data exist describing how dexamethasone affects the immune system systemically and intratumorally in glioblastoma patients – particularly in the context of immunotherapy.

METHODS
We evaluated the dose-dependent effects of dexamethasone when administered with anti-PD-1 and/or radiotherapy in immunocompetent C57BL/6 mice with syngeneic GL261 or CT-2A glioblastoma tumors, including analyses of intracranial tumors, draining lymph nodes, and spleen. Clinically, the effect of dexamethasone on survival was additionally evaluated in 181 consecutive IDH-wildtype glioblastoma patients treated with anti-PD-(L)1, with adjustment for relevant prognostic factors.

RESULTS
Despite the inherent responsiveness of GL261 to immune checkpoint blockade, concurrent dexamethasone administration with anti-PD-1 therapy decreased survival in a dose-dependent fashion and decreased survival following anti-PD-1 plus radiotherapy in both GL261 and immunoresistant CT-2A models. Dexamethasone quantitatively decreased T lymphocytes by reducing the proliferation while increasing apoptosis. Dexamethasone also decreased lymphocyte functional capacity. Myeloid and NK cell populations were also generally reduced. Thus, dexamethasone negatively affects both the adaptive and innate immune responses. As a clinical correlate, a retrospective analysis of 181 consecutive IDH-wildtype glioblastoma patients treated with PD-(L)1 blockade revealed worse survival among those on baseline dexamethasone. Upon multivariable adjustment with relevant prognostic factors, baseline dexamethasone use – regardless of dose – was the strongest predictor of poor survival (reference no dexamethasone; &lt; 2mg HR 2.28, 95%CI=1.41–3.68, p=0.001; ≥2mg HR 1.97, 95%CI=1.27–3.07, p=0.003).

CONCLUSIONS
Our preclinical and clinical data indicate that concurrent dexamethasone therapy may be detrimental to immunotherapeutic approaches for glioblastoma patients. Our preclinical analyses also suggest that dexamethasone’s detrimental effects are dose-dependent, suggesting that the lowest possible dose should be used for patients when dexamethasone use is unavoidable. Careful evaluation of dexamethasone use is warranted for neuro-oncology patients undergoing immunotherapy clinical trials.
IMMU-14. ONCOLYTIC ADENOVIRUS DELTA-24-RGD ENGINEERED TO EXPRESS 4-1BBL AS A THERAPEUTIC APPROACH FOR DIPG
Authors: Laspidea Virginia , Puigdelloses Montserrat , Martinez-Velez Naiara , Garcia-Moure Marc , Labiano Sara , Ausejo Iker , Patiño-García Ana , Becher Oren J , Jiang Hong , Gupta Sumit , Fueyo Juan , Gomez-Manzano Candelaria , M Alonso Marta 
Published: December 2020

Abstract
Despite the advances in our understanding of pediatric diffuse midline gliomas (DMG) they remain the leading cause of pediatric death caused by cancer. Our group has demonstrated that the administration of Delta-24-RGD in DIPG models is safe and therapeutically efficacious. An on-going clinical trial with this virus has proven to be safe for these patients. To further improve the anti-tumoral response of the virus, we armed Delta-24-RGD with 4-1BBL (Delta-24-ACT). 41BB is a costimulatory receptor that promotes the survival and expansion of activated T cells, and the generation and maintenance of memory CD8+ T cells. Here, we showed that in vitro Delta-24-ACT can infect and express 4-1BBL in murine and human DIPG cell lines. Importantly, 4-1BBL expression in DIPG cell lines was able to activate lymphocytes and increase their IFN-gamma production. In addition, Delta-24-ACT triggered immunogenic cell death in DIPG cell lines, as shown by the release of DAMPs such as ATP, HMGB1, Hsp90a and calreticulin translocation. Delta-24-ACT administration in orthotopic DIPG models was well tolerated and safe. We confirmed the expression of the ligand within the tumor. Moreover, using flow cytometry and multispectral immunohistochemistry we observed profound changes in the tumor microenvironment with an increase in the T-cell populations and a remodeling of the myeloid component before and after treatment. Functional studies showed no differences in lymphocytes isolated from mice treated splenocytes but uncovered TILS that showed a significantly increased in the production of IFN-gamma. Delta-24-ACT treatment of mice bearing orthotopic DIPG murine tumors resulted in a significant increase in the median survival and led to free of disease long-term survivors. In summary, Delta-24-ACT is a virus that builds in our clinical experience with Delta-24-RGD in DIPG patients going a step further to boost the antitumor effect of viral therapy while maintaining a safe profile.
IMMU-17. SINGLE-CELL RNA-SEQ REVEALS HIGH-GRADE GLIOMA ASSOCIATED MICROGLIA WITH PROINFLAMMATORY AND STEM-LIKE FEATURES SUPPORT TUMOR PROGRESSION
Authors: Liu Hailong , Liu Yongqiang , Franco-Barraza Janusz , Yu Xinguang , Feng Shiyu 
Published: December 2020

Abstract
Poor response of human glioblastoma to current therapies are influenced by tumor microenvironment. Although glioblastoma is recognized by large enrichment of microglia, characterization of diverse cell subsets and their functions remain challenging because of high heterogenicity. Here, we analyzed single-cell transcriptomics to comprehensively map the cell populations and determine the roles of microglia in IDH1/2 wild-type (IDH-wt) glioblastoma progression. Besides finding microglia were significantly enriched in IDH-wt glioblastoma compared to IDH1/2 mutant (IDH-mut) gliomas, we identified a unique high-grade glioma microglia (HGAM) subtype characterized by proinflammatory and stem-like features. In particular, HGAM’s pro-tumoral IL1β secretion is mediated via ApoE-induced activation of NLRP1 inflammasome. HGAM phagocytosed OPC-like malignant cells forming the neoplastic microglia, which presented the stem-like potential giving rise to activated microglia. Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation. Additionally, an intricated evaluation of glioma patients revealed that SETD2 mutation/low-expression correlated with adverse prognosis. Further analysis showed that SETD2 -dificient tumor cells presented hypersensitivity to HGAM-derived IL1β via epigenetic dysregulation of PHF6. Also, SETD2 -deficient tumor cells produced TGF-β1 contributing to microglia activation. Finally, targeting the TGF-β1/TβRI signaling impaired HGAM activation and tumor growth. Our studies identify a unique neoplastic microglia subpopulation and establish cellular basis of interactions with tumor cells important for disease progression.
IMMU-20. SINGLE-CELL RNASEQ OF TUMOR INFILTRATING IMMUNE CELLS FROM NEOADJUVANT ANTI-PD1 TREATED GBM PATIENTS REVEALS GLOBAL TRANSCRIPTIONAL CHANGES AND IMMUNOSUPPRESSIVE ADAPTIVE RESPONSES BY MYELOID CELLS
Authors: Lee Alexander , Mochizuki Aaron , Chow Frances , Reynoso Jeremy , Orpilla Joey , Sun Lu , Chavez Carolina , Galvez Mildred , Kienzler Jenny , Yong William , Everson Richard , Nathanson David , Bensinger Steven , Liau Linda , Cloughesy Timothy , Hugo Willy , Prins Robert 
Published: December 2020

Abstract

INTRODUCTION
Neoadjuvant anti-PD1 therapy (neo-aPD1) was previously shown to significantly increase the survival of recurrent glioblastoma patients in a small randomized clinical trial. However, neo-aPD1 alone was not curative so defining the limitations of neo-aPD1 and discovering where other immunotherapies can be used alongside neo-aPD1 is needed.

METHODS
To understand how immune cells in the tumor microenvironment change with neo-aPD1, we used single-cell RNAsequencing to analyze cells from 27 glioma patients (n = 105,143 cells) of which 9 patients had received neo-aPD1 (n = 33,325 cells). Using unsupervised clustering and pseudotime trajectory analysis, we characterized the transcriptional changes within immune cells and how these populations changed with therapy.

RESULTS
We defined the immune landscape of the glioblastoma tumor microenvironment. Compared to no immunotherapy treatment, neo-aPD1 significantly increased the ratio of T cells to myelo-monocytic cells and led to significant increases in the effector and memory T cell populations but no significant changes in myeloid cell composition. Our differential gene expression analysis of the myeloid compartment showed significant increases in interferon-γ-responsive genes and down-regulation of genes associated with M2 macrophages and MDSCs, suggestive that neo-aPD1 influences the transcriptional profile of myeloid cells in the tumor microenvironment. Interestingly, our psuedotime trajectory analysis showed that neo-aPD1 was associated with cells expressing both lymphoid and myeloid-related genes, which we theorized to actually be lymphoid-myeloid cell doublets caused by increased interactions between myeloid and lymphoid cells. These doublets were highly enriched in MHC I and II, macrophage, T cell, and T cell activation and exhaustion genes indicating that neo-aPD1 may result in some adaptive immunosuppressive mechanism by increasing these interactions. This could explain why neo-aPD1 alone is not curative for glioblastoma patients.

CONCLUSIONS
In total, neoadjuvant anti-PD1 therapy enhances effector T cell activity, but may concomitantly induce adaptive resistance mediated by myeloid cells in glioblastoma.
IMMU-26. UNRAVELING ANTIGEN PRESENTATION IN CENTRAL NERVOUS SYSTEM ANTI-TUMOR IMMUNITY
Authors: Bowman-Kirigin Jay , Kobayashi Dale , Livingstone Alexandra , Saunders Brian , Schaettler Max , Liu Connor , Durai Vivek , Bowman-Kirigin Jay , Leuthardt Eric , Kim Albert , Zipfel Gregory , Osbun Joshua , Chicoine Michael , Murphy Kenneth , Zinselmeyer Bernd , Johanns Tanner , Dunn Gavin 
Published: December 2020

Abstract
The antigen presenting cell that primes T cells in the central nervous system (CNS) remains unknown. Outside the CNS, the conventional dendritic cell 1 (cDC1) subset presents antigen to and primes CD8 T cells. However, the steady-state CNS parenchyma is relatively devoid of all dendritic cell subsets, including cDC1. cDC1 are required for anti-tumor immunity a variety of other tumor types, but their role CNS tumors remains undefined. Using the orthotopic preclinical glioblastoma models, GL261 and CT2A, we characterized the role of cDC1 in the CNS anti-tumor immune response. While cDC1 are absent in the steady state brain, tumor presence drove recruitment of cDC1 into extravascular spaces within the tumor and adjacent brain parenchyma. We further found that while GL261-bearing wildtype mice experienced survival benefit following anti-PDL1 checkpoint blockade treatment, mice with cDC1 genetically deleted experienced no survival benefit. cDC1-deficient mice completely lacked neoantigen-specific CD8 T cells against the endogenously-primed GL261-neoantigen mutant Imp3, and possessed broad CD8 effector T cell defects compared to wild type mice. Furthermore, using a fluorescent tumor-associated reporter, we detected tumor-derived material within dendritic cells from the tumor, the lymphatic vessel-containing dura, and the cervical lymph nodes. We observed the human cDC1-equivalent CD141+ cDC within human brain tumors (not limited to GBM) and dura as well. We used the GBM-specific reporter, 5-aminoilevulinic acid/protoporphyrin IX (PPIX) fluorescent metabolite to resect the tumor, and observed PPIX specifically in conventional dendritic cell subsets that had infiltrated the resected tumor, but not within those same cell subsets in the periphery, nor in T cells within the tumor. These findings comport with the canonical understanding that cDC1 uptake antigen at the effector site and migrate to draining lymph nodes to prime effector CD8 T cells, and highlight the significant role that cDC1 play in CNS anti-tumor immunity in mice and humans.