bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A041: Hypoxia-responsive CAR T-cells
Authors: Sarén Tina Anna , Senz Anne Marie , Ramachandran Mohanraj , Yu Di , Essand Magnus
Published: February 2019

In recent years, CD19 CAR T-cell therapy has been successfully implemented against therapy-resistant B-cell malignancies. The results are especially striking for acute lymphoblastic leukemia (ALL), while results are somewhat less stunning when it comes to lymphoma. This is in part due to the semi-solid structure of lymphoma with an immune suppressive tumor microenvironment and less oxygenated areas within the tumors. These obstacles become even more pronounced in solid tumors. Furthermore, in the case of solid tumors the lack of tumor-specific antigens represents a major challenge. Instead, overexpressed tumor-associated antigens (TAAs) are often used as targets in CAR T-cell therapy of solid tumors. However, as TAAs are also expressed to some extent in normal tissue, targeting these antigens may result in severe OFF-tumor ON-target toxicity. In the case of CD19 CAR T-cell therapy of B-cell malignancies, OFF-tumor ON-target toxicity causes B-cell aplasia.The aim of this study was to reduce OFF-tumor ON-target toxicity by engineering CAR T-cells that mainly express the CAR molecule in the hypoxic tumor microenvironment. Hypoxia-inducible factor 1 (HIF1) is a transcription factor that is a major mediator of hypoxia-induced gene expression as it binds to hypoxia response elements (HREs) in promoter regions of hypoxia-responsive genes and initiates their expression. In this study, a cassette of HREs was inserted together with a minimal CMV (mCMV) promoter in front of the CD19 CAR cassette to promote expression during hypoxic conditions. Chemically induced hypoxia augmented CD19 CAR expression over time in hypoxia-responsive CD19 CAR T-cells (HRE-mCMV-CD19CAR-GFP), whereas CAR expression was unaffected in CD19 CAR T-cells with constitutively expressed CAR (EF1α-CD19CAR-GFP). Furthermore, hypoxia-responsive CAR T-cells had an increased activation status and killing capacity upon antigen encounter in hypoxic compared to normoxic conditions. This design could be evaluated in the clinic to reduce B-cell aplasia in CD19 CAR T-cell therapy of lymphomas and especially to reduce OFF-target toxicities from CAR T-cells targeting TAAs in solid tumors.

Citation Format: Tina Anna Sarén, Anne Marie Senz, Mohanraj Ramachandran, Di Yu, Magnus Essand. Hypoxia-responsive CAR T-cells [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A041.
Abstract A069: NIM15 blockade – A new stroma-targeting approach for the treatment of epithelial ovarian cancer
Authors: Ferber Dyke , Suarez-Carmona Meggy , Momburg Frank , Meyer Marten , Rothenheber Rebecca , Lenoir Bénédicte M.A. , Schott Sarah , Zoernig Inka , Jäger Dirk , Halama Niels
Published: February 2019

Despite the immense research over the past decade in the cancer immunology field, which has led to several clinical trials and FDA and EMA approvals of biologicals for the reinvigoration of T-cell-mediated cancer cell killing in diverse tumor entities, the long-term survival of patients with advanced epithelial ovarian cancer is still devastating. These results therefore imply the need for a more intensive investigation of the tumor microenvironment in this cancer type in order to enhance disease outcome and improve the effectiveness of current immunotherapeutics. We herein show for the first time efficacy data of a novel treatment approach for the specific targeting of the stromal tumor compartment in a human tissue explant culture model of high-grade serous ovarian cancer. Antibody-mediated blockade of NIM15, a protein suspected to be predominantly expressed by tumor-associated macrophages and cancer-associated-fibroblasts in ovarian cancer, has the potential to polarize the immune landscape in a subset of patients from a stromal-dense and immunosuppressive one into a Th1-M1-supportive microenvironment, as measured by cytokine pattern analyses and semiautomated immune cell quantification. Abrogating the effects of secreted NIM15 unleashes in vitro proliferation of T-cell subsets and increases the production of cytokines and chemokines involved in innate and adaptive antitumor immune responses in our tissue culture explant model. In order to unravel the mechanistic relations behind the observed effects, we plan further experiments to prove whether these might be due to a disruption of the collagen-dense tumor stroma and a repolarization of the secretory profile of tumor-associated macrophages and fibroblasts. In summary, we hope to develop a pharmacologic tool that converts immune-depleted, “cold” cancer types into T-cell infiltrated ones and therewith provide a rationale for combination treatment approaches, like anti-PD1 blockade or adoptive cell transfer, to further ameliorate the so far poor response of metastasized, refractory ovarian cancer.

Citation Format: Dyke Ferber, Meggy Suarez-Carmona, Frank Momburg, Marten Meyer, Rebecca Rothenheber, Bénédicte M.A. Lenoir, Sarah Schott, Inka Zoernig, Dirk Jäger, Niels Halama. NIM15 blockade – A new stroma-targeting approach for the treatment of epithelial ovarian cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A069.
Abstract A072: Calreticulin exposures by malignant blasts correlate with robust anticancer immunity and improved clinical outcome in AML patients
Authors: Fucikova Jitka
Published: February 2019

Cancer cell death can be perceived as immunogenic by the host only when malignant cells emit immunostimulatory signals (so-called “damage-associated molecular patterns,” DAMPs), as they die in the context of failing adaptive responses to stress. Accumulating preclinical and clinical evidence indicates that the capacity of immunogenic cell death to (re-)activate an anticancer immune response is key to the success of various chemo- and radiotherapeutic regimens. Malignant blasts from patients with acute myeloid leukemia (AML) exposed multiple DAMPs, including calreticulin (CRT), heat-shock protein 70 (HSP70), and HSP90 on their plasma membrane irrespective of treatment. In these patients, high levels of surface-exposed (ecto)-CRT correlated with an increased proportion of natural killer cells and effector memory CD4+ and CD8+ T-cells in the periphery. Moreover, CRT exposure on the plasma membrane of malignant blasts positively correlated with the frequency of circulating T-cells specific for leukemia-associated antigens, indicating that ecto-CRT favors the initiation of anticancer immunity in patients with AML. Finally, although the levels of ecto-HSP70, ecto-HSP90, and ecto-CRT were all associated with improved relapse-free survival, only CRT exposure significantly correlated with superior overall survival. Thus, CRT exposure represents a novel powerful prognostic biomarker for patients with AML, reflecting the activation of a clinically relevant AML-specific immune response.

Citation Format: Jitka Fucikova. Calreticulin exposures by malignant blasts correlate with robust anticancer immunity and improved clinical outcome in AML patients [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A072.
Abstract A075: A protective role for group 3 innate lymphoid cells in colitis-associated colorectal cancer
Authors: Goc Jeremy , Bessman Nick , Sahota Sheena , Laure Flamar Anne , Putzel Gregory , Withers David , Arthur Janelle , Shah Manish , Sonnenberg Gregory
Published: February 2019

Chronic inflammation is recognized as a causative factor in the development of cancer and recent paradigms suggest that microbe-driven chronic inflammation is causally associated with the development and progression of cancer in the colon. Further, recent studies in mice have implicated innate lymphoid cells (ILC) as a key cell population that regulates intestinal inflammation. Group 3 innate lymphoid cells (ILC3) are essential regulators of immunity, inflammation and tissue homeostasis in the intestine, yet their role in cancer remains poorly defined. Here, we identify that ILC3 are associated with both human and mouse colon tumors. Tumor-associated ILC3 are selectively localized within lymphoid aggregates and exhibit a unique phenotypic profile as compared with nonmalignant tissue. Critically, mice with a selective deletion of ILC3-specific MHCII exhibit a striking increased susceptibility to intestinal tissue damage and develop highly invasive and flat colorectal tumors. These data demonstrate a protective role for antigen-presenting ILC3 in the context of cancer development and progression in the intestine, and suggest that further interrogation may lead to the development of novel immunotherapeutic strategies in colon cancer.

Citation Format: Jeremy Goc, Nick Bessman, Sheena Sahota, Flamar Anne Laure, Gregory Putzel, David Withers, Janelle Arthur, Manish Shah, Gregory Sonnenberg. A protective role for group 3 innate lymphoid cells in colitis-associated colorectal cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A075.
Abstract A079: Secreted IL-12p70 from long-term activated dendritic cells is lost concomitant with their apoptosis and release of IL-10
Authors: Hansen Morten , Carstensen Laura Stentoft , Obers Andreas , Svane Inge Marie Stentoft
Published: February 2019

The intimate balance between peripheral tolerance and adaptive immunity has profound implications in several disease settings. Interleukin-12 (IL-12) plays a major role in immunity to intracellular pathogens and cancer by controlling IFNγ-dependent adaptive immunity. The transient production of the bioactive IL-12p70 heterodimer and the concurrent expression of interleukin-10 (IL-10) serves as a myeloid checkpoint to avoid immunopathology. Here, long-term exposure to inflammatory stimuli was evaluated on monocyte-derived dendritic cells (DCs) activated with lipopolysaccharide (LPS) and gamma interferon (IFNγ). The secretion of IFNγ from co-cultures with allogeneic T-cells present in peripheral blood mononuclear cells from healthy volunteers served as a measure of T-cell activation.The secretion of IFNγ from co-cultures was progressively lost as exposure of DCs to inflammatory stimuli was extended from one up to four days prior to co-culture or following IL-12p70 antibody-mediated blockade. Most pronounced was the 12-fold reduction (N = 9 donor pairs) seen with four-day activated DCs. Furthermore, at four days of activation, a significant fraction of DCs underwent apoptosis concomitant with their increased release of IL-10 and a striking 10-fold drop in levels of IL-12p70 as compared with DCs activated one, two or three days. Furthermore, after four days of activation, DC-derived IL-12p70 was inversely correlated with IL-10 and with IFNγ derived from co-cultures. It is currently an open question whether IL-12p70 naturally degrades after four days of activation or whether apoptotic DCs actively stimulate the degradation of IL-12p70.

Citation Format: Morten Hansen, Laura Stentoft Carstensen, Andreas Obers, Inge Marie Stentoft Svane. Secreted IL-12p70 from long-term activated dendritic cells is lost concomitant with their apoptosis and release of IL-10 [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A079.
Abstract A090: The Duffy Antigen Receptor for Chemokines (DARC) influences levels of tumor-associated leukocytes in the breast tumor microenvironment
Authors: Martini Rachel , Jenkins Brittany D. , Yates Clayton , Newman Lisa , Davis Melissa
Published: February 2019

The regulation of immune cell infiltration into the tumor microenvironment can influence disease prognosis. The specific populations that are present can inform potential treatment options. This work investigates immune cell regulation in the breast cancer tumor microenvironment, specifically how an atypical chemokine receptor, known as the Duffy Antigen Receptor for Chemokines (DARC/ACKR1) can influence levels of leukocyte populations in the breast tumor environment. DARC is a nonsignaling receptor able to bind both the CC and CXC classes of chemokines, and mainly functions to modulate levels of chemokines in circulation, and aid in chemokine transport in tissues. In this regard, DARC expression may determine the profile of immune response.To investigate DARC expression and its effects on tumor-associated leukocyte (TAL) populations, we obtained RNA-seq data from The Cancer Genome Atlas (TCGA) Breast Cancer cohort. We proceeded through our analysis with those samples denoted as primary tumor samples (n=400). To estimate the relative abundance of TAL populations, we used the CIBERSORT online platform, which estimates fractions of 22 different TAL populations based on gene expression data. After completing the CIBERSORT analysis, we proceeded with only those samples that had a significant CIBERSORT output (n=167). In our analysis, we found that the total abundance of all TALs was significantly higher in tumors that have high DARC expression (p < 0.0001), and that DARC expression and the TAL abundance are positively and significantly correlated (R = 0.545, p < 0.0001). When we investigated specific TAL populations, we saw that B cell, T-cell, monocyte and macrophage populations were significantly increased in tumors with high DARC expression.

Citation Format: Rachel Martini, Brittany D. Jenkins, Clayton Yates, Lisa Newman, Melissa Davis. The Duffy Antigen Receptor for Chemokines (DARC) influences levels of tumor-associated leukocytes in the breast tumor microenvironment [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A090.
Abstract A091: IL-33 activates antitumoral toxicity in eosinophils through stimulation of contact-dependent degranulation
Authors: Mattei Fabrizio , Buccione Carla , Andreone Sara , Spadaro Francesca , Ninno Adele De , Mancini Jacopo , Zanetti Cristiana , Parolini Isabella , Iosi Francesca , Tinari Antonella , Lucarini Valeria , Gerardino Annamaria , Ziccheddu Giovanna , Businaro Luca , Afferni Claudia , Schiavoni Giovanna
Published: February 2019

The alarmin IL-33 plays pleiotropic roles in allergy, autoimmunity and inflammation through binding to its specific receptor ST2 expressed by most hematopoietic cells. Emerging evidences suggest an involvement of this cytokine also in cancer immunity, although its function remains ill-defined. Eosinophils (EOS) are a rare blood population playing critical roles in allergic inflammation and parasitic responses. We recently showed that EOS play an essential role in anti-tumor responses against melanoma growth and pulmonary metastasis mediated by IL-33 in vivo.In the present study we analyzed the mechanisms by which IL-33 mediates tumor infiltration and antitumoral activities of EOS. We show that IL-33 indirectly stimulates the recruitment of EOS inducing tumor-derived chemokines CCL24 and CCL5. Furthermore, IL-33 directly activates EOS inducing the expression of adhesion molecules, such as the integrin CD11b, resulting in efficient contact-dependent tumor cell killing. In co-culture experiments, IL-33 activated EOS tightly bond to tumor cells, forming increased numbers of conjugates, with respect to resting eosinophils. Confocal laser-scanning microscopy (CLSM) of eosinophil-tumor cell conjugates revealed polarization of the pore-forming eosinophilic cationic protein (ECP) and of CD11b on the cell synapses exclusively in IL-33-activated, but not resting, EOS. Furthermore, we show that IL-33 activated EOS release larger amounts of extracellular vesicles (EV) with respect to resting EOS. Transmission electron microscopy (TEM) revealed increased degranulation and EV release of IL-33-activated EOS following cell contact with target tumor cells. Our results advocate for an eosinophil-mediated tumoricidal function promoted by IL-33, thus opening perspectives for novel cancer immunotherapy strategies.

Citation Format: Fabrizio Mattei, Carla Buccione, Sara Andreone, Francesca Spadaro, Adele De Ninno, Jacopo Mancini, Cristiana Zanetti, Isabella Parolini, Francesca Iosi, Antonella Tinari, Valeria Lucarini, Annamaria Gerardino, Giovanna Ziccheddu, Luca Businaro, Claudia Afferni, Giovanna Schiavoni. IL-33 activates antitumoral toxicity in eosinophils through stimulation of contact-dependent degranulation [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A091.
Abstract A094: Characterization of pancreatic cancer endothelial cells: Approach to enhance immune cell infiltration for immunotherapy
Authors: Nakajima Kosei , Ino Yashunori , Iwasaki Toshimitsu , Hiraoka Nobuyoshi
Published: February 2019

The hurdles in realizing immunotherapy success for cure stem from the fact that cancer patients are either refractory to immune response and/or develop resistance. We previously proposed that these phenomena are due, in part, to the deployment of tumor-associated antigens, or employment of tumor-associated endothelium acting as a gatekeeper for immune cell infiltration into the cancer tissue (Nakajima et al, Cancer Res 2017;77:5441-4). Here, an extensive study unveiled functional/molecular differences of endothelium derived from pancreatic cancer and normal pancreas. They were isolated from fresh surgical specimen by magnet-based selection. The primary culture of tumor-associated endothelial cells was confirmed by double positive expressions of endothelial markers, CD31 and ERG1. They showed the short vessel formations and the narrow area of capillary network, indicating the low potential of angiogenesis. Further, peripheral blood–derived lymphocytes were less adhering to the tumor-associated endothelial cells. To find the molecular differences, microarray analysis was performed, and identified 2748 molecules distinct from endothelial cells of noncancerous tissues (p<0.05). Then, a bioinformatic approach, i.e., ingenuity pathway analysis (IPA) reconstructed 47 pathways (p<0.05). Among them, TNFR1 signaling appeared as a highly possible pathway, which is involved in immune cell infiltration: (p=0.005, z score=2.00) with aberrantly expressed upstream molecules of the pathway. As for the downstream molecules, ICAM1 was highly expressed, whereas VCAM1 and E-selectin were generally suppressed on pathologic specimens of pancreatic cancer (n=20) as well as primary cultured tumor-associated endothelial cells. The unfulfilled expressions may be causes of noninflamed immune microenvironment of pancreatic cancer. Thus, our study highlights possible molecular candidates of tumor-associated endothelium shaping tumor microenvironment to enhance immune cell infiltration for successful immunotherapy.

Citation Format: Kosei Nakajima, Yashunori Ino, Toshimitsu Iwasaki, Nobuyoshi Hiraoka. Characterization of pancreatic cancer endothelial cells: Approach to enhance immune cell infiltration for immunotherapy [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A094.
Abstract A096: The potential role of fibroblast activation protein as a natural killer cell immune checkpoint
Authors: O'Connell Allison , Wang Shangzi , Weiner Louis M.
Published: February 2019

Fibroblast activation protein (FAP) is a type II transmembrane serine protease that functions as both a dipeptidyl peptidase and an endopeptidase. FAP is minimally expressed in normal pancreas but overexpressed in 90% of pancreatic ductal adenocarcinoma (PDAC) specimens. A meta-analysis of PDAC studies demonstrated elevated tumor FAP expression is associated with worse clinical outcomes. While immunotherapy offers remarkable results for certain cancer types, it has been largely ineffective in PDAC. This lack of efficacy may be attributed to the dense stromal fibrosis, comprised largely of pancreatic stellate cells (PSCs), that is characteristic of PDAC lesions. Here we demonstrate that human NK cell line (NK92) is activated by and kill PSCs. Upon direct contact with PSCs, NK92 cells upregulate FAP. FAP expression by NK92 cells is associated with an inactivation phenotype. Talabostat, a non-specific inhibitor of FAP, enhances NK92 killing of PSCs in vitro and enhances PDAC tumor clearance in vivo. This suggests that FAP may be a novel NK cell immune checkpoint that can be pharmacologically modulated to enhance NK cell antitumor activity.

Citation Format: Allison O'Connell, Shangzi Wang, Louis M. Weiner. The potential role of fibroblast activation protein as a natural killer cell immune checkpoint [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A096.
Abstract A099: Using high-throughput phenotypic screening to identify therapeutic targets for the inhibition of myeloid-derived suppressor cells
Authors: Petrova Elissaveta , Schäffner Sandra , Pieck Jan-Carsten , Herhaus Christian , Rippmann Friedrich , Pöschke Oliver , Helming Laura
Published: February 2019

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immature myeloid cells with immunosuppressive function, which inhibit the antitumor activity of T-cells and natural killer (NK) cells. MDSC number is greatly increased in tumor-bearing mice and in cancer patients, and in the clinic, MDSC accumulation is associated with cancer progression, recurrence, and poor response to chemo-, radio- and immunotherapies. The increasing evidence for the clinical significance of MDSC has triggered a strong interest in the therapeutic modulation of their function. To date, however, limited progress has been made in this direction, as a major challenge in the field remains the identification of suitable therapeutic targets for the development of novel drugs. Here, we describe a systematic approach in which a small-molecule high-throughput phenotypic screen was used to identify MDSC targets and pathways of therapeutic relevance. This screen was based on a validated in vitro mouse mononuclear MDSC (M-MDSC) model, in which hematopoietic progenitors, immortalized using a NUP98/HOXB4 transgene, were differentiated into immunosuppressive MDSC. Using this model, we developed a 384-well-based phenotypic screening assay, in which the suppressive effect of mouse M-MDSC on CD8+ T-cell proliferation and cytokine secretion was monitored. We screened a small molecule library, comprising 5000+ biologically active compounds with known target(s), and identified 116 compounds that potently disrupted MDSC suppression of T-cell function. With the help of chemoinformatics methods, reported target activities associated with the compounds were annotated, and a set of targets and pathways of potential significance for MDSC-driven immunosuppression was identified. Altogether, this work provides insight into the signaling nodes that could be of relevance for MDSC function, and offers a path forward for the therapeutic targeting of MDSC.

Citation Format: Elissaveta Petrova, Sandra Schäffner, Jan-Carsten Pieck, Christian Herhaus, Friedrich Rippmann, Oliver Pöschke, Laura Helming. Using high-throughput phenotypic screening to identify therapeutic targets for the inhibition of myeloid-derived suppressor cells [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A099.
Abstract A127: Role of macrophage subsets in liver metastasis
Authors: Deng Zihou , Geissmann Frederic
Published: February 2019

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal disease and frequently metastasize to the liver. The presence of macrophages (F4/80+ cells or CD68+ cells) is reported to correlate with tumor progression and metastasis in pancreatic cancer. Emerging evidence has revised the traditional concept of macrophage ontogeny and made it increasingly apparent that there exists functional diversity between resident macrophages originating from yolk sac erythro-myeloid progenitors (EMPs) and hematopoietic stem cells (HSCs)-derived macrophages. Sophisticated therapeutic intervention requires in-depth understanding of these macrophage subsets in the metastasis microenvironment. However, the role and heterogeneity of macrophages in tumor development, in particular in PDAC liver metastasis, remains poorly understood.

Here, we utilized murine PDAC model to inidcate that Kupffer cells and tumor associated macrophages (TAMs) are two developmentally and functionally distinct subsets of macrophages. Removal of Kupffer cells by depletion of Id3 in macrophage progenitors or CSF1R blockade increases tumor burden. These findings reveal that Kupffer cells play a key role in restraining PDAC liver metastasis and show the necessity to understand macrophage origin when developing therapeutics for cancer treatment.

Citation Format: Zihou Deng, Frederic Geissmann. Role of macrophage subsets in liver metastasis [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A127.
Abstract A149: EµTel-Jak2 T-ALL mouse model is dependent upon Myb function and susceptible to immune checkpoint therapy
Authors: Roth Sara , Sampurno Shienny , Waibel Michaela , Cluse Leonie , Pereira Lloyd A. , Johnstone Ricky W. , Ramsay Robert G.
Published: February 2019

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic cancer, predominantly in children but patients over 50 years are also affected. While high-intensity combination chemotherapy is effective in 90% of young patients, only 30–40% of adult patients with ALL will achieve long-term remission. Furthermore, the severe side effects observed in young and old patients highlight the need for alternative therapy options. To explore the role of drivers of ALL and thus the potential for other therapy options we crossed EµTEL-JAK2 mice, a mouse model of T-ALL, with MybPlt4/Plt4 mice, which express hypomorphic alleles of Myb resulting in 40% of WT Myb function. EµTEL-JAK2 x MybPlt4/Plt4 mice showed a significant prolonged survival compared to EµTEL-JAK2 Myb+/+ mice, indicating that EµTEL-JAK2 cells are dependent upon fully functional Myb. Hence, we initiated a preclinical study targeting Myb with our TetMyb DNA vaccine combined with immune checkpoint inhibitors in C57BL/6 mice bearing transplanted Eµ TEL-JAK2 T-ALL cells. Interestingly, therapeutic treatment with TetMyb DNA vaccine and anti-PD-1 antibody therapy did not enhance overall survival. However, therapeutic monotherapy with anti-CTLA-4 antibody therapy on day 2, 7, 12, 16 and 21 after EµTEL-JAK2 transplant significantly reduced leukemic cell frequency in the peripheral blood and significantly prolonged survival. Further evaluation, especially in combination with current standard of care, is needed, but our results suggest a promising therapeutic option of anti-CTLA-4 antibody therapy in T-ALL.

Citation Format: Sara Roth, Shienny Sampurno, Michaela Waibel, Leonie Cluse, Lloyd A. Pereira, Ricky W. Johnstone, Robert G. Ramsay. EµTel-Jak2 T-ALL mouse model is dependent upon Myb function and susceptible to immune checkpoint therapy [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A149.
Abstract A150: Enhancing abscopal responses to radiation therapy by manipulating autophagy
Authors: Rybstein Marissa , Yamazaki Takahiro , Martinez Aitziber Buque , Galluzzi Lorenzo
Published: February 2019

Background: Macroautophagy (autophagy) is an evolutionary conserved cellular mechanism culminating with the lysosomal degradation of dispensable, damaged or potentially toxic cytoplasmic structures (e.g., permeabilized mitochondria). Autophagy helps cancer cells to adapt to harsh environmental conditions and to resist therapy. However, autophagy is also key for multiple steps of the anticancer immune response. Thus, whether autophagy should be inhibited or activated in the context of cancer therapy remains debated (Rybstein et al., Nat Cell Biol 2018). Since autophagy has been shown to play a key role in removal of cytosolic DNA, which is one mechanism leading to type I interferon (IFN) secretion, and since type I IFN is required for systemic immune responses activated by radiation therapy (RT), we asked the question as to whether selectively inhibiting autophagy in cancer cells may boost the ability of RT to initiate anticancer immunity. Methods/Tools: CRISPR/Cas9 technology was used to render mouse mammary carcinoma TSA and EO771 cells autophagy-deficient and chemical inhibitors of autophagy were also employed. Autophagy-competent versus –deficient systems were characterized for autophagy proficiency (by immunoblotting), growth (in vitro and in vivo), resistance to cell death induced by starvation, chemotherapy and RT (by multicolor flow cytometry and clonogenic assays) and production of type I IFN (by PCR and ELISA). Abscopal responses have been assessed in vivo. Results: In line with previous observations, autophagy inhibition reduced the growth of mouse mammary carcinoma cells, in vitro and in vivo, limited their clonogenic potential (at baseline) and increased their sensitivity to multiple stressors. Moreover, pharmacologic and genetic autophagy inhibition increased the capacity of mouse mammary carcinoma cells to secrete type I IFN in response to radiation. Finally, immunocompetent mice bearing syngeneic autophagy-deficient mouse mammary carcinoma cells mounted improved abscopal responses to RT (in the context of CTLA4 blockade) as compared to immunocompetent mice bearing syngeneic autophagy-competent cells, as determined by growth inhibition of a distant, non-irradiated, autophagy-competent lesion. Perspectives: We will test the innovative hypothesis that selective autophagy inhibition in cancer cells may synergize with autophagy activation at the whole-body level (by nutrient restriction or physical exercise), hence enabling superior therapeutic responses to radiation.

Citation Format: Marissa Rybstein, Takahiro Yamazaki, Aitziber Buque Martinez, Lorenzo Galluzzi. Enhancing abscopal responses to radiation therapy by manipulating autophagy [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A150.
Abstract A158: Delivering type I interferon to dendritic cells empowers tumor eradication and immune combination treatments
Authors: Tavernier Jan H.
Published: February 2019

An ideal generic cancer immunotherapy should mobilize the immune system to destroy tumor cells without harming healthy cells and remain active in case of recurrence. Furthermore, it should preferably not rely on tumor-specific surface markers, as these are only available in a limited set of malignancies. Despite approval for treatment of various cancers, clinical application of cytokines is still impeded by their multiple toxic side effects. Type I interferon (IFN), for instance, has a long history in the treatment of cancer, but its multifaceted activity pattern and complex side effects prevent its optimal clinical use. Here we develop AcTakines (Activity-on-Target cytokines), optimized (mutated) immunocytokines that are up to 1000-fold more potent on targeT-cells, allowing specific signaling in selected cell types only. As conventional dendritic cells (cDC) are essential for IFN antitumor efficacy, we targeted type I IFN-derived “AcTaferon (AFN)” to Clec9A+ cDC. Clec9A-AFN therapy displayed strong antitumor activity in murine melanoma (B16), breast carcinoma (4T1) and lymphoma models (A20), as well as against human RL lymphoma in immunodeficient NSG mice reconstituted with a human immune system. In sharp contrast to wild-type IFN therapy, the antitumor efficacy of Clec9A-AFN was not accompanied by any detectable toxicity, assessed by body weight and several hematologic parameters. Clec9A-AFN effects were lost in CD8-depleted or Batf3-/- mice, and depended on IFN signaling in cDCs but not in T lymphocytes. Combined with anti-PDL1 immune checkpoint blockade, Treg-depleting anti-CTLA4 + anti-OX40 therapy, immunogenic chemotherapy, or low-dose TNF, complete tumor regressions and long-lasting tumor immunity (memory) were obtained, still without any adverse effects. Our findings thus indicate that DC-targeted AFN provides a highly efficient, off-the-shelf and safe cancer immunotherapy, with possible application in a broad range of malignancies.

Citation Format: Jan H. Tavernier. Delivering type I interferon to dendritic cells empowers tumor eradication and immune combination treatments [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A158.
Abstract A160: Deep immunoprofiling of mouse lung cancer models in steady state and upon drug treatment.
Authors: Maldegem Febe van , Valand Karishma , Tsang Victoria , Mugarza Edurne , Caswell Deborah , Hobson Philip , Downward Julian
Published: February 2019

With the advancement of immunotherapies for lung cancer, it has become apparent how insufficient our knowledge is surrounding the interactions between the tumor and the immune system. In particular in the context of combining immunotherapy with conventional chemotherapy or novel targeted therapies, it is of the utmost importance that we understand the effects that those therapies have on the tumor immune infiltrate and how that would counteract or synergize with immunotherapy. We have used multiplex flow cytometry to characterise the basal tumor immune infiltrate of various spontaneous and orthogonous syngeneic mouse models for lung cancer, with different levels of immunogenicity. With imaging mass cytometry, visualizing and quantifying >30 markers simultaneously in mouse tumor tissue sections, we studied the localization and interactions of the immune cells within and surrounding the tumors. This has highlighted the level to which tumors are regulating their microenvironment, actively excluding all potential effector cells while attracting protumoral myeloid cells, and how this is amplified as the tumors progress. We have observed differences between the various models and seen how the tumors make adaptations when they are intrinsically more immunogenic. Furthermore, we have started to address how these balances are perturbed by various immune and chemotherapies in short- and long-term experiments and preliminary data will be presented.

Citation Format: Febe van Maldegem, Karishma Valand, Victoria Tsang, Edurne Mugarza, Deborah Caswell, Philip Hobson, Julian Downward. Deep immunoprofiling of mouse lung cancer models in steady state and upon drug treatment. [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A160.
Abstract A168: Quiescent stem cells evade immune surveillance
Authors: Agudo Judith , Merad Miriam , Brown Brian D.
Published: February 2019

There is a long-standing interest in understanding the immunogenicity of adult stem cells due to their role in tissue homeostasis, regeneration and oncogenesis. Notably, their self-renewing capacity means they are long-lived, and can accumulate mutations over time, which would result in neoantigens. These neoantigens could make stem cells potential targets of T-cells. However, whether they are subject to immune surveillance is unknown. Here, we utilized a novel technology to study immune responses against virtually any cell type, along with specific stem cell mouse models, to interrogate the immunogenicity of adult stem cells in their niche in vivo. We found that immune privilege is not a general property of adult stem cells. Instead, our studies revealed that most epithelial stem cells, such as those in the gut and ovary, are subjected to immune clearance, but that highly quiescent stem cells escape immune detection. This is an intrinsic property of the resting stem cells resulting from downregulation of MHC class I and other key components of the antigen presentation machinery, which results in complete protection from immune attack. These studies established that quiescent tissue stem cells hide from immune surveillance and protect their integrity. This helps to understand why mutations in long-lived stem cells do not lead to immune clearance and suggests how cancer stem cells may evade immune surveillance.

Citation Format: Judith Agudo, Miriam Merad, Brian D. Brown. Quiescent stem cells evade immune surveillance [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A168.
Abstract A178: Nr4a transcription factors limit CAR T-cell function in solid tumors
Authors: Chen Joyce , Scott-Browne James P. , Lopez-Moyado Isaac F. , Hempleman Laura J. , Seo Hyungseok , Sekiya Takashi , Yoshimura Akihiko , Rao Anjana
Published: February 2019

In cancer immunotherapy, CD19-targeted CAR T-cells have exhibited impressive clinical efficacy against B cell leukemias and lymphomas; however, they have been less effective against solid tumors. This is in part because CAR T-cells enter a hyporesponsive (“exhausted” or “dysfunctional”) state that is triggered by chronic antigen stimulation and characterized by upregulation of several inhibitory receptors and loss of effector function. To identify transcriptional regulators and other candidates contributing to the diminished function of CAR T-cells in solid tumors, we developed a CAR T-cell model in which recipient mice bearing murine melanoma tumors expressing the human CD19 antigen were adoptively transferred with CD19-targeted CAR T-cells. Genome-wide analyses of these mouse tumor-infiltrating lymphocytes (TILs) showed that endogenous CD8+ TILs and CAR T TILs selected for expression of high levels of PD-1 and TIM3 exhibited similar profiles of gene expression and chromatin accessibility, associated with secondary activation of the Nr4a nuclear receptor family of transcription factors by the transcription factor NFAT. We demonstrate that in both CAR T TILs and endogenous CD8+ TILs, the Nr4a proteins Nr4a1 (Nur77), Nr4a2 (Nurr1), and Nr4a3 (Nor1) are prominent effectors of the transcriptional program downstream of NFAT: they promote the expression of inhibitory receptors and genes associated with early stages of the exhausted/ dysfunctional state, and limit effector function. Most importantly, treatment of tumor-bearing mice with CAR T-cells lacking all three Nr4a transcription factors (Nr4aTKO) resulted in tumor regression and prolonged survival. Nr4aTKO tumor-infiltrating CAR T-cells displayed a gene expression profile characteristic of effector function, including increased expression of granzymes, cytokines and the transcription factor T-bet. Many of these gene expression changes were associated with altered regulatory element accessibility near effector genes. Our data identify Nr4a transcription factors as major players in the cell-intrinsic program of T-cell hyporesponsiveness and point to Nr4a inhibition as a promising strategy for cancer immunotherapy.

Citation Format: Joyce Chen, James P. Scott-Browne, Isaac F. Lopez-Moyado, Laura J. Hempleman, Hyungseok Seo, Takashi Sekiya, Akihiko Yoshimura, Anjana Rao. Nr4a transcription factors limit CAR T-cell function in solid tumors [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A178.
Abstract A179: Targeting UCP2 pathway in melanoma cells reprograms the tumor microenvironment and initiates antitumor immune cycle
Authors: Cheng Wan-Chen
Published: February 2019

Immune checkpoint blockade treatment displays promising therapeutic efficiency in different cancer types. However, a significant proportion of patients are refractory to this treatment due to lack of T-cell infiltration in tumors, a phenotype known as “cold tumors.” To improve the therapeutic benefits of checkpoint blockade, it is crucial to address how to escalate T-cell infiltration into tumors. Here, we characterized melanoma patients in The Cancer Genome Atlas (TCGA) into either high or low T-cell antitumor responses. We then identified the mRNA expression level of mitochondrial uncoupling protein 2 (UCP2) positively correlates with T-cell antitumor immune responses and prolonged patients survival. By using murine melanoma model, we revealed that overexpressing UCP2 in melanoma cells elevates CD8+ T-cell infiltration into the tumor microenvironment (TME) in a conventional type 1 dendritic cell (cDC1)-dependent manner and normalize tumor neovasculature. Mechanistically, UCP2 induction in tumor cells alters the cytokine milieu in tumors and stimulates the recruitment of cDC1 through a IRF5-CXCL10 chemokine axis. Hence, enhancing the expression of UCP2 in melanoma cells provides immunostimulatory shift by engaging the cDC1-CD8+ T-cell dependent antitumor immune cycle in the TME. Interestingly, we demonstrated that inducing UCP2 expression in melanoma cells by genetic approach or administration of rosiglitazone, an approved antidiabetic PPAR agonist, can sensitize PD-1 blockade-resistant melanomas to anti-PD-1 antibody treatment. Accordingly, our data indicate that targeting UCP2 in melanoma cells can be a potent strategy to increase antitumor response to checkpoint blockades in non-T-cell-inflamed tumors.

Citation Format: Wan-Chen Cheng. Targeting UCP2 pathway in melanoma cells reprograms the tumor microenvironment and initiates antitumor immune cycle [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A179.
Abstract A182: T-cell exhaustion assessment using a fully automated sequential chromogenic multiplex assay
Authors: Collignon Aurélie , Benchaaben Assil , Martirosyan Anna , Duval Matthieu , Bonzom Emilie , Prestat Emmanuel , Haond Christophe , Fieschi Jacques
Published: February 2019

Cancer immunotherapy by anti-PD-1 or anti-PD-L1 antibodies is now established as an efficient approach to restore the cytotoxic activity of exhausted T-cells. However, the strong and durable response observed in non-small cell lung cancer (NSCLC) patients is limited to a fraction of the treated population. Biomarkers, such as PD-L1 expression on tumor cells or tumor mutational burden, are approved as predictive markers of the response to anti-PD-1 or anti-PD-L1 antibodies. However, they are far from perfect to select patients eligible to immunotherapy. Since exhausted T-cells express more than one checkpoint inhibitor, it is hypothesized that an anti-PD1 antibody may not be sufficient to restore the activity of exhausted cells. Multiplex detection of the major immune checkpoints, i.e., PD-1, LAG-3 and TIM-3, on T-cells within the tumor microenvironment could, on one hand, predict the poor response to a single agent and could, on the other hand, predict the best combination of antibodies targeting more than one immune checkpoint. Here we present an automated sequential chromogenic multiplex assay allowing the assessment of the expression of PD-1, LAG-3 and TIM-3 on CD3+/CD8+ cells on a single FFPE tumor tissue section. Briefly, a tissue section is sequentially stained, digitized, unstained and restained with antibodies targeting the five markers. Images of the whole slide are then analyzed by digital pathology. First, a newly developed software is used to co-register the 5 virtual slides and perform colors deconvolution. Detection of positive cells is performed for each marker independently, using Indica Lab’s HALO software. Then, individual cells can be analyzed to identify complex phenotypes and assess their density on the entire tissue section. In addition, tissue segmentation tools are used to assess densities of exhausted T-cells expressing the major immune checkpoints in parenchyma, tumor stroma and invasive margin regions. The quantitative evaluation of T-cells’ exhaustion based on the expression of more than one immune checkpoint could improve patient stratification and lead to individualized combinations of immunotherapy agents.

Citation Format: Aurélie Collignon, Assil Benchaaben, Anna Martirosyan, Matthieu Duval, Emilie Bonzom, Emmanuel Prestat, Christophe Haond, Jacques Fieschi. T-cell exhaustion assessment using a fully automated sequential chromogenic multiplex assay [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A182.