bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract A31: High aneuploidy levels are linked to a reduced immune-cell abundance in metastatic castrate-resistant prostate cancer
Authors: Vidotto Thiago , Salles Daniela C. , Lotan Tamara L. 
Published: March 2020

Abstract
Single-agent immunotherapeutic approaches are promising for treating castrate-resistant prostate cancer (CRPC) patients; however, to date no significant improvement in survival has been reported. Mixed response to therapy occurs because metastatic lesions are highly heterogeneous. These lesions exhibit distinct genomic changes that are linked to a tumor microenvironment that is often poorly populated by immune cells. In other tumor types, a high percent genome altered (e.g., aneuploidy) associates with an overall reduction in immune response in the primary tumor microenvironment. However, the association between genomic changes and immune cell composition is poorly understood in metastatic prostate cancers. Thus, we quantified the abundance of 22 immune cell types in 330 tumors from two independent public domain CRPC cohorts and 491 primary prostate tumors from TCGA using the Absolute Mode from CIBERSORT. The estimation in CRPC was performed using whole-transcriptome data from West Coast Dream Team (Abida et al., 2019; n=212) and East Coast Dream Team (Robinson et al., 2015; n=117) samples. We did not identify any significant correlations between mutational load and immune cell abundance in the three investigated cohorts. In primary tumors, aneuploidy was weakly negatively correlated with CD8+ and CD4+ T-cell abundance (R=-0.14 and R=-0.09, P&lt;0.05). Overall, metastatic lesions demonstrated a low absolute abundance of the majority of immune cell subtypes, with higher levels of CD8+ T-cells, memory CD4+ T-cells, macrophages, and plasma cells. We found that bone lesions had the lowest abundance of CD8+ T-cells (Kruskal-Wallis, p=0.05) and the highest abundance of macrophages (P&lt;0.0001) compared to lymph node and liver samples. Overall, aneuploidy was negatively correlated with immune cell abundance in both metastatic cohorts (Spearman correlation, P&lt;0.05). Interestingly, lymph node metastases showed the strongest negative correlation between aneuploidy and T-cell abundance in both West and East cohorts (R=-0.36 and R=-0.32, respectively, p&lt;0.01). Our preliminary results show that the extent of chromosomal aberrations in CRPC is significantly associated with underlying immune cell infiltrates. These results have potential implications for future immunotherapy trials in prostate cancer.
Citation Format: Thiago Vidotto, Daniela C. Salles, Tamara L. Lotan. High aneuploidy levels are linked to a reduced immune-cell abundance in metastatic castrate-resistant prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A31.
Abstract A52: Systemic anti-PD-1 immunotherapy results in PD-1 blockade on T cells in the cerebrospinal fluid
Authors: Wang Dongrui , Portnow Jana , Tran Vivi , Chiu Vivian , Brito Alfonso , Alizadeh Darya , Starr Renate , Kilpatrick Julie , McNamara Paige , Forman Stephen J. , Badie Behnam , Synold Timothy W. , Brown Christine E. 
Published: March 2020

Abstract
Immune checkpoint inhibitors have shown promising clinical efficacy in many types of cancers, including some with metastasis into the central neural system (CNS). However, little is known about the CNS penetration of immune checkpoint inhibitors and their bioactivity on the locoregional T cells. Here, we analyzed the CNS and systemic concentration of pembrolizumab (Pembro) in high-grade glioma patients, who were concurrently treated with intravenously administered Pembro and locoregionally delivered chimeric antigen receptor (CAR) T cells. A total of 99 paired cerebrospinal fluid (CSF) and serum samples were collected from 10 patients during multicycle treatment of CAR T cell and Pembro. We discovered that after the first Pembro infusion, CSF antibody concentrations were increased slower than serum concentrations. However, CSF antibody concentrations reached steady-state 24 hours after Pembro infusion and were maintained stable over the 21-day infusion cycles. Although average CSF Pembro concentrations (3.2nM) were only 1% of serum levels (329nM), we observed effective PD-1 blockade on the T cells in CSF samples of all analyzed patients. The blocking effect was found on both endogenous T cells and locoregionally administered CAR T cells. Further, PD-1 on CD3/CD28 beads-activated T cells was completely blocked after incubation with cell-depleted CSF samples, suggesting the bioactivity of Pembro that penetrated into the CSF. Using a dose-titration assay, we also confirmed that CSF Pembro concentrations were sufficient to ameliorate the cytotoxic activity of CAR T cells against repetitive tumor challenges. Together, for the first time, we showed the dynamic Pembro levels in the CSF throughout multiple treatment cycles and confirmed that systemically administered immune checkpoint inhibitors can penetrate into the CNS and elicit blocking effect on T cells. Our findings add strength to the rationale for combining immune checkpoint inhibitors with locoregionally delivered CAR T cells and other types of immunotherapy for the treatment of brain tumors.
Citation Format: Dongrui Wang, Jana Portnow, Vivi Tran, Vivian Chiu, Alfonso Brito, Darya Alizadeh, Renate Starr, Julie Kilpatrick, Paige McNamara, Stephen J. Forman, Behnam Badie, Timothy W. Synold, Christine E. Brown. Systemic anti-PD-1 immunotherapy results in PD-1 blockade on T cells in the cerebrospinal fluid [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A52.
Abstract A55: Uncovering the mechanism of Trib1 in cancer immunotherapy
Authors: Iheanacho Franklin , Stein Sarah J. , Rome Kelly S. , Jordan Martha S. , Pear Warren S. 
Published: March 2020

Abstract
T cells provide a fundamental role in cell-mediated immunity, but during chronic antigen exposure such as in the case of cancer, T cells begin to lose effector function and undergo exhaustion. Our goal is to find a target within T cells that could be manipulated to prolong T-cell function and reduce tumor growth. Initial experiments focused on the pseudokinase Trib1, as data suggest that Trib1 acts as a negative regulator of T-cell activation. T cells isolated from mice in which Trib1 was specifically ablated within the T-cell compartment produced more IL-2 compared to wild-type T cells. T cells lacking Trib1 also proliferated more than wild-type T cells. In mice lacking Trib1 in grafted tumor models, tumor growth was reduced. These observations suggest that Trib1 restricts T-cell activation and function. Trib1 is a pseudokinase that is thought to act as a scaffolding molecule to facilitate protein interactions. To understand the mechanism by which Trib1 regulates T-cell function, we performed a proteomic screen to identify interacting partners. The screen was performed in Jurkat cells, an immortalized human T-cell line, expressing a FLAG/strep tagged Trib1. A FLAG pulldown was performed to isolate Trib1, and interacting partners were identified by mass spectrometry. The screen revealed two interacting partners: RFWD2, an E3 ubiquitin ligase also known as COP1, and DET1, a binding partner of COP1. These results provide evidence that Trib1 interacts with COP1 in T cells and suggest that this interaction might be important in the regulation of T-cell function and the regression of tumor growth.
Note:This abstract was not presented at the conference.
Citation Format: Franklin Iheanacho, Sarah J. Stein, Kelly S. Rome, Martha S. Jordan, Warren S. Pear. Uncovering the mechanism of Trib1 in cancer immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A55.
Abstract A61: Human leukocyte antigen G as a novel target for switch-based chimeric antigen receptor natural killer cell therapy of solid cancers
Authors: Jan Chia-Ing , Huang Shi-Wei , Canoll Peter , Lin Yu-Chuan , Lu Hsin-Man , Chio Shao-Chih , Cho Der-Yang 
Published: March 2020

Abstract
Human leukocyte antigen G (HLA-G) is a molecule within the tumor microenvironment (TME) that modulates the innate and adaptive immune systems by interacting with inhibitory receptors on the surface of immune cells and thus functions as an immune checkpoint. It could be potentially expressed by all tumor types but is not expressed by either healthy tissues surrounding the tumor cells or vital normal tissues. Chimeric antigen receptors (CARs) for adoptive cell therapy (ACT) have been successful in clinical trials against hematologic cancers; however, challenges have been encountered when applying this approach to the treatment of solid tumors. These obstacles are mainly due to the lack of a ubiquitous tumor-associated antigen (TAA) across different tumor types without “on-target/off-tumor” reactivity and the immunosuppressive nonphysical TME. To address these issues, we developed a novel switch HLA-G CAR carrying an inducible Caspase9 (iC9) suicide gene system that binds to HLA-G1~G7 isoforms and expressed this CAR in natural killer (NK) cells. We tested these HLA-G CAR-NK cells in a variety of adult cancer models and discovered that they mediate significant tumor cytolysis in triple-negative breast cancer (TNBC), glioblastoma (GBM), pancreatic (PA) cancer, and ovarian (OV) cancer in vitro and in TNBC and GBM xenograft models in vivo. Coculturing HLA-G CAR-NK cells with vital normal cell lines did not cause cell damage. We further discovered that surface-exposed HLA-G is chemoinducible, which in turn increases tumor sensitivity to both HLA-G CAR effector-mediated antitumor responses and tumor-infiltrative NK cells. The underlying mechanism of tumor and HLA-G CAR NK cell interaction may be through upregulation of membranous HLA-G via demethylation of the TAP-1 promoter or enhanced activity of the TAP1/signal peptide peptidase (SPP) pathways. In conclusion, HLA-G CAR-NK cells could be an option for treating solid tumors of different cell types, and a regimen comprising chemotherapy followed by HLA-G CAR immunotherapy may improve responses compared to those achieved with CAR-T cell immunotherapy alone.
Citation Format: Chia-Ing Jan, Shi-Wei Huang, Peter Canoll, Yu-Chuan Lin, Hsin-Man Lu, Shao-Chih Chio, Der-Yang Cho. Human leukocyte antigen G as a novel target for switch-based chimeric antigen receptor natural killer cell therapy of solid cancers [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A61.
Abstract A77: Antibody targeting tumor-derived soluble NKG2D ligand sMIC provides dual costimulation of CD8 T cells and enables sMIC+ tumors to respond to PD1/PD-L1 blockade therapy
Authors: Zhang Jinyu , Larrocha Pablo , Dhar Payal , Wu Jennifer 
Published: March 2020

Abstract
Background: Insufficient costimulation accounts for a great deal of the suboptimal activation of cytotoxic CD8 T cells (CTLs) and presumably unsatisfactory clinical expectation of PD1/PDL1 therapy. Tumor-derived soluble NKG2D ligands are associated with poor clinical response to PD1/PDL1 blockade therapy in cancer patients. One of the most frequently occurring tumor-derived soluble NKG2D ligands, the soluble MHC I chain-related molecule (sMIC), can impair costimulation to CD8 T cells. We investigated whether cotargeting sMIC can provide optimal costimulation to CTLs and enhance the therapeutic effect of PD1/PDL1 blockades.
Methods: Single-agent therapy of a PD1/PDL1 blockade antibody or a sMIC-targeting non-blocking antibody or a combination therapy of the two antibodies were applied to well-characterized preclinical MIC/sMIC+ tumor models that closely resemble the NKG2D-mediated oncoimmune dynamics of MIC+ cancer patients. Therapeutic efficacy and associated effector mechanisms were evaluated.
Results: We show that antibody cotargeting sMIC enables or enhances the response of sMIC+ tumors to PD1/PD-L1 blockade therapy. The therapy response of the combination therapy was associated with enhanced antigen-specific CD8 T-cell enrichment and function in tumors. We show that cotargeting sMIC with a nonblocking antibody provides antigen-specific CD8 T cells with NKG2D and CD28 dual costimulation, in addition to elimination of inhibitory signals, and thus amplifies antigen-specific CD8 T-cell antitumor responses.
Conclusion: Our findings provide the proof-of-concept rationale and previously undiscovered mechanisms for cotargeting sMIC to enable and enhance the response to PD1/PDL1 blockade therapy in sMIC+ cancer patients.
Citation Format: Jinyu Zhang, Pablo Larrocha, Payal Dhar, Jennifer Wu. Antibody targeting tumor-derived soluble NKG2D ligand sMIC provides dual costimulation of CD8 T cells and enables sMIC+ tumors to respond to PD1/PD-L1 blockade therapy [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A77.
Abstract A78: Preclinical evaluation of 3D185, a novel potent inhibitor of FGFR1/2/3 and CSF-1R, in FGFR-dependent and macrophage-dominant cancer models
Authors: Dai Yang , Ji Yichun , Shen Yanyan , Su Yi , Liu Bo , Wang Yueliang , Sun Deqiao , Jiang Yuchen , Zha Chuantao , Xie Zuoquan , Ding Jian , Geng Meiyu , Ai Jing , Peng Xia , Hou Pengcong , Chen Yi 
Published: March 2020

Abstract
The interaction between tumor cells and their immunosuppressive microenvironment promotes tumor progression and drug resistance. Thus, simultaneously targeting tumor cells and stromal cells is expected to have synergistic antitumor effects. Herein, we present the preclinical antitumor investigation of 3D185, a novel dual inhibitor targeting FGFRs, which are oncogenic drivers, and CSF-1R, which is the major survival factor for protumor macrophages. The antitumor characteristics of 3D185 were assessed by a range of assays, including kinase profiling, cell viability, cell migration, immunoblotting, CD8+ T-cell suppression, and in vivo antitumor efficacy, followed by flow cytometric and immunohistochemical analyses of tumor-infiltrating immune cells and endothelial cells in nude mice and immune-competent mice. We found that 3D185 significantly inhibited the kinase activity of FGFR1/2/3 and CSF-1R, with equal potency and high selectivity over other kinases. 3D185 suppressed FGFR signaling and tumor cell growth in FGFR-driven models both in vitro and in vivo. In addition, 3D185 could inhibit the survival and M2-like polarization of protumor macrophages, reversing the immunosuppressive effect of macrophages on CD8+ T cells as well as CSF1-differentiated macrophage induced-FGFR3-aberrant cancer cell migration. Furthermore, 3D185 inhibited tumor growth via remodeling the tumor microenvironment in TAM-dominated tumor models. In summary, 3D185 is a dual inhibitor against FGFR1/2/3 and CSF-1R that exhibits potent antitumor activities. This compound is promising because it simultaneously targets tumor cells per se and the immunosuppressive tumor microenvironment to synergistically antagonize tumors. Our study provides a solid foundation for the investigation of 3D185 in cancer patients, particularly in patients with aberrant FGFR and abundant macrophages, who respond poorly to classic pan-FGFRi treatment. Now 3D185 is in phase I clinical trials.
Citation Format: Yang Dai, Yichun Ji, Yanyan Shen, Yi Su, Bo Liu, Yueliang Wang, Deqiao Sun, Yuchen Jiang, Chuantao Zha, Zuoquan Xie, Jian Ding, Meiyu Geng, Jing Ai, Xia Peng, Pengcong Hou, Yi Chen. Preclinical evaluation of 3D185, a novel potent inhibitor of FGFR1/2/3 and CSF-1R, in FGFR-dependent and macrophage-dominant cancer models [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A78.
Abstract A91: T-cell regulation in pancreatic ductal adenocarcinoma
Authors: Sivakumar Shivan , Abu-Shah Enas , Ahern David , Mangal Nagina , Reddy Srikanth , Rendek Aniko , Soonawalla Zahir , Silva Michael , Middleton Mark , Dustin Michael L. 
Published: March 2020

Abstract
Background: Pancreatic cancer has the worst prognosis of any human malignancy. We have shown using transcriptomics and histopathology that immune infiltrate in resection samples from a Whipple’s operation is predictive of prognosis. In particular, lymphocytes appear to be a major prognostic marker. With promising immunotherapies being proposed for other cancers, there is a need for a deeper understanding of the immune landscape of pancreatic cancer to identify points of intervention.
Methods: We have developed a 37-marker mass cytometry staining panel to characterize the dominant immune populations within primary pancreatic cancer. Our panel further analyzes T-cell subpopulations and their functional status, including a host of clinically relevant checkpoint markers and immunosuppressive signatures.
Results: The degree of immune infiltration we observe is highly variable between patients, but all patients equivocally show a complex immune microenvironment consistent of macrophages, neutrophils, and different lymphocytes. The T cells infiltrating the tumor, both CD4 and CD8 T cells, appear to be dysfunctional with hardly any activation signature. A highly suppressive phenotype also characterizes the regulatory T-cell population. Our data suggest that the microenvironment of pancreatic cancer is extremely suppressive and could be a major driver of poor prognosis. Yet, this work identifies potential therapeutic targets and avenues that should be further investigated and may inspire future clinical trials.
Future Work: We are planning to investigate the behavior of T-regs from PDAC using in vitro assays. To that end, we will use a recently developed advanced 3D culture system to visualize their interactions with CD8s and the functional consequences of those interactions on CD8-mediated killing.
Citation Format: Shivan Sivakumar, Enas Abu-Shah, David Ahern, Nagina Mangal, Srikanth Reddy, Aniko Rendek, Zahir Soonawalla, Michael Silva, Mark Middleton, Michael L. Dustin. T-cell regulation in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A91.
Abstract A92: Analysis of lung-resident macrophages as potential regulators of disseminated tumor cell fate
Authors: Dalla Erica , Casanova-Acebes Maria , Hung Margaret , Linde Nina , Merad Miriam , Aguirre-Ghiso Julio 
Published: March 2020

Abstract
The majority of cancer-related deaths are due to metastasis at secondary organs originating from solitary disseminated tumor cells (DTCs), which can remain dormant for several years. In the lung, some DTCs undergo a period of dormancy before proliferation to form metastasis, while others will not grow into metastatic lesions. As macrophages are key immune components of the microenvironment at distant sites, we aim to understand their potential role in regulating DTC dormancy and awakening. To test the contribution of lung macrophages to cancer cell proliferation, we first compared the effect of lung-resident alveolar macrophages (AMs) and bone marrow-derived monocytes (BM MOs) on cancer cell phenotypes. Our results indicate that AMs may suppress growth and induce EMT (CDH1lo/TWIST1hi phenotype) in cancer cells (of both early and late stages), while BM MOs promote growth. We further assessed the effect of these distinct macrophage populations on survival and proliferation of single cancer cells in a 3D matrigel assay to mimic single DTCs in the lung. Here, AMs appear to retain cancer cells as single cells, while BM MOs favor a switch to proliferation and colony growth. We further used conditioned media (CM) from lung cultures from naive and macrophage-depleted animals to study how organ-specific cues from macrophages affected tumor cell growth. We performed a proteomic analysis of the lung secretome and identified DKK3 as differentially produced before and after macrophage depletion. DKK3, a regulator of Wnt signaling, was absent in the depleted condition. We then tested its effect on cell proliferation in mammary cancer cell sphere formation assays, and we observed that DKK3 increased sphere formation and growth of early- and late-stage cells, respectively. We will next test whether DKK3 production is derived from AMs, BM MOs, or other lung resident cells and we will profile AMs and BM MOs from early and late stages of tumor progression to determine their gene expression profiles at different times of DTC colonization. To explore the role of AMs in dormancy in vivo, we will perform AM depletion in the CD169-DTR animal model. Here, we will deplete specifically tissue-resident AMs and determine DTC fate after tail-vein injection of breast cancer cells. Our study will thus allow us to determine the contribution of different macrophage populations to metastatic dormancy.
Citation Format: Erica Dalla, Maria Casanova-Acebes, Margaret Hung, Nina Linde, Miriam Merad, Julio Aguirre-Ghiso. Analysis of lung-resident macrophages as potential regulators of disseminated tumor cell fate [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A92.
Abstract A97: Neutrophil extracellular traps (NETs) promote immune escape and metastatic growth after surgical stress
Authors: Yazdani Hamza O. , Kaltenmeier Christof T. , Geller David , Tohme Samer 
Published: March 2020

Abstract
Introduction: Surgery induces local and systemic inflammatory and immunosuppressive disturbances that correlate with adverse cancer outcomes. Following surgical stress, NETs promote the growth of liver micrometastases. We hypothesize that NETs support metastatic growth by promoting immune escape.
Methods: Liver ischemia reperfusion was performed 5 days after a murine liver metastatic model was established.
Results: Liver PD-L1 expression increased and peaked between 6-48 hours after reperfusion. A smaller peak of PD-L1 was observed after 2 weeks as the metastatic tumors grew. During the first 48 hours, the predominant source of PD-L1 was CD45+-CD11b+-Ly6G+ cells. PD-L1 expression was significantly decreased when NETs were inhibited either genetically by using PAD4KO mice or DNAse injections. In vitro, we confirmed both human and murine NETs express high levels of PD-L1. After liver I/R, tumor-infiltrating T cells expressed inhibitory receptors and were highly dysfunctional with reduced cytokine production and proliferative capacity in the NET-rich tumors compared to tumors from sham mice. T-cell exhaustion was reversed in mice treated with DNAse or PAD4KO mice. Similar results were observed in vitro as NETs suppressed T-cell function via PDL-1/PD-1 interaction. Treating mice with anti-PD-L1 during the first 48 hours after reperfusion reversed T-cell exhaustion and decreased tumor growth.
Conclusion: NETs induced by surgical stress cause immune escape by secreting PD-L1, increasing T-cell exhaustion, and upregulation of immunosuppressive ligands on tumor cells. These findings suggest avenues for overcoming the perioperative accelerated tumor growth and immunosuppressive state and ultimately improving long-term oncologic outcomes.
Citation Format: Hamza O. Yazdani, Christof T. Kaltenmeier, David Geller, Samer Tohme. Neutrophil extracellular traps (NETs) promote immune escape and metastatic growth after surgical stress [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A97.