bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract B09: Targeting scavenger receptors for immunotherapy of cancer
Authors: Boura Vanessa F. , Tyystjärvi Sofia , Oliynyk Ganna , Arsenian-Henriksson Marie , Karlsson Mikael C.I. , Sohn Silke
Published: June 2021

Background: Tumor-associated macrophages (TAM) play an important role in tumor-promoting inflammation and have been associated with poor prognosis in many human cancers. Recently, we showed that class A scavenger receptor MARCO is a specific marker for the immune-suppressive tumor-promoting TAM subtype in different tumor models. Targeting MARCO by monoclonal antibodies (Ab) could reprogram the protumorigenic TAM towards a proinflammatory phenotype with antitumor activity, leading to decreased tumor growth and metastases formation in three different mouse tumor models.

Aim(s): The current immunotherapies are estimated to treat less than 50% of all cancers; therefore, it is of high importance to develop new targets and combinatorial therapies. In this study, we aim to define the role of scavenger receptor MARCO on TAM in more detail and the mechanisms of how targeting MARCO by monoclonal Ab modulates macrophage phenotype and tumor microenvironment. Moreover, we are investigating how it can be used as a possible anticancer therapeutic approach used as single or combinatorial treatment.

Results: Our recent data demonstrate that using anti-MARCO Ab in combination with other immune checkpoint inhibitors, such as anti-CTLA-4 Ab, further decreases the tumor volume by 40-50% in the B16 melanoma model. For example, different checkpoint Ab combined with anti-MARCO Ab shows a reduction from average tumor volume 500mm3 in single treatments to 250mm3 (p=0.0101) in the combinatorial treatment. Currently, we are investigating what happens in the tumor microenvironment on a cellular level after using the different combinatorial treatments. Moreover, we see increased ATP release of MARCO+ macrophages in vitro after engagement of MARCO as well as enhanced glycolysis in anti-MARCO Ab treated macrophages compared to the control group.

Conclusion: Checkpoint inhibitors targeting T cells are already used in the clinics and the anti-MARCO Ab targeting TAM is a promising candidate to use in combination with checkpoint inhibitors to even further increase the survival rate of patients. The understanding of MARCO signaling and how this leads to a shift towards proinflammatory macrophages would not just benefit the field of basic macrophage biology but will also be an important step in translating the anti-MARCO Ab therapy from mice to humans as a new approach for cancer immunotherapy.

Citation Format: Vanessa F. Boura, Sofia Tyystjärvi, Ganna Oliynyk, Marie Arsenian-Henriksson, Mikael C.I. Karlsson, Silke Sohn. Targeting scavenger receptors for immunotherapy of cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B09.
Abstract B19: Robust antitumor effect of doxorubicin prodrug combined with anti-PD-1 in murine squamous cell cancer model
Authors: Lee Yoon Se , Kwon Minsu , Son In Kyung , Byun Youngro , Kim Sang Yoon
Published: June 2021

Background: Combination therapy of anti-PD-1 agents with other class of chemotherapeutic agents to improve treatment outcome is being attempted. Anthracycline-derived chemotherapeutic agents are known to activate immunogenic cell-death mechanism. Previously, we developed caspase-3 specific prodrug, MPD-1 containing doxorubicin. It is linked to peptide moiety cleavable by caspase-3 produced during apoptosis induced by radiation therapy (RT). We hypothesized that anti-PD-1 alone may activate MPD-1 by producing caspase-3 and reinforce antitumor efficacy of MPD-1 and anti-PD-1 effect. This study was designed to evaluate the antitumor effects of combined treatment of anti-PD-1 and MPD-1 in murine squamous cell carcinoma models.

Methods: Murine SCC VII (squamous cell carcinoma) cells were inoculated to flank of mice, female C3H/J. We divided 6 treatment groups; control, RT, anti-PD-1, anti-PD-1 with MPD-1, RT with MPD-1, and triple therapy (anti-PD-1 + RT + MPD-1) (n = 5/each group). After tumor grew up to 100-200 mm3, treatment was initiated. Tumor size and mice weight were measured. Expression of caspase-3 was evaluated in cell lines and tumor tissues after each treatment. Distribution of CD8+, CD4+, and FoxP3+ cells was analyzed.

Results: RT with MPD-1, anti-PD-1 with MPD-1, and triple treatment enhanced the synergistic antitumor activity compared to single treatment in SCC VII bearing mice. Anti-PD-1 with MPD-1 presented slightly better antitumor effect than RT with MPD-1. Caspase-3 was produced in tumor tissue of anti-PD-1 treatment group, which enhanced antitumor effect of activated MPD-1, while cell after anti-PD-1 did not enhance caspase-3 expression. Triple treatment suppressed tumor growth mostly, which was sustained more than 2 weeks even after cessation of treatment. Proportion of CD45+CD8+ T-cells in triple treatment group was increased mostly among tumor-infiltrating lymphocytes. Body weight of each treatment group was not significantly different.

Conclusion: Systemic anti-PD-1 initiates apoptosis and produces caspase-3. This process activates MPD-1 and induces sequential mediated by tumor-infiltrating lymphocytes. Combined anti-PD-1 and MPD-1 treatment will be effective for the distant metastatic lesions.

Citation Format: Yoon Se Lee, Minsu Kwon, In Kyung Son, Youngro Byun, Sang Yoon Kim. Robust antitumor effect of doxorubicin prodrug combined with anti-PD-1 in murine squamous cell cancer model [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B19.
Abstract B30: Transient interferon suppression renders nerve sheath sarcomas susceptible to targeted viroimmunotherapy
Authors: Ghonime Mohammed G. , Cassady Kevin A.
Published: June 2021

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas resistant to most cancer treatments. Surgical resection remains the primary treatment; however, this is often incomplete, ultimately resulting in high mortality and morbidity rates. There has been a resurgence of interest in oncolytic virotherapy because of encouraging preclinical and clinical trial results. Oncolytic Herpes simplex virus (oHSV) selectively replicates in cancer cells, lysing the cell and inducing antitumor immunity. We previously showed that basal interferon (IFN) signaling increases interferon stimulated gene (ISG) expression, restricting viral replication in almost 50% of MPNSTs. The FDA-approved drug ruxolitinib (RUX) temporarily resets this constitutively active STAT signaling and renders the sarcoma cells susceptible to oHSV infection in cell culture. In the studies described, we translated our in vitro results into a syngeneic MPNST tumor model. Consistent with our previous results, murine MPNSTs exhibit a similar IFN- and ISG-mediated resistance mechanism and virotherapy alone provides no antitumor benefit in vivo. However, when mice are pretreated with ruxolitinib, this reduces ISG expression, making the tumors susceptible to oHSV infection. Ruxolitinib pretreatment improves viral replication and alters the oHSV-induced immune-mediated response. Our results show that this combination therapy increases CD8 T-cell activation in the tumor microenvironment and that this population is indispensable for RUX+oHSV antitumor benefit. Of note, animals treated with the combination therapy have developed a systemic circulating memory response against the specific tumor antigen. These data suggest JAK inhibition prior to oncolytic virus treatment augments both oHSV replication and the immunotherapeutic efficacy of viroimmunotherapy.

Citation Format: Mohammed G. Ghonime, Kevin A. Cassady. Transient interferon suppression renders nerve sheath sarcomas susceptible to targeted viroimmunotherapy [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B30.
Abstract B39: Regulation and function of IL-1b in immune modulation of pancreatic cancer
Authors: Das Shipra , Vogt Sandra , Hadju Christina , Bar-Sagi Dafna
Published: June 2021

Pancreatic intraepithelial neoplasms (PanINs) are well-defined precursor lesions of pancreatic ductal adenocarcinoma (PDA). The initiation and progression of PanINs is marked by dynamic stromal reconstruction and localized acute inflammation. Using an orthotopic transplantation model of early and advanced pancreatic neoplasia in immunocompetent recipient mice, we have uncovered a crucial role for the cytokine IL-1b in KRasG12D-driven PanIN evolution. Tumor cell-derived IL-1b¢ was found to be critical for shaping the protumorigenic PanIN microenvironment by promoting activation of quiescent pancreatic stellate cells and establishing an immunosuppressive milieu mediated by M2 macrophages, MDSCs and CD1dhiCD5+ regulatory B cells. Furthermore, loss of IL-1 signaling in tumor stroma activates the cytotoxic T-cell immune response, significantly attenuates PanIN growth and confers survival advantage to PDAC-bearing mice. Tumor cell expression of IL-1b in vivo is driven by upregulation of TLR4 signaling and activation of the NLRP3 inflammasome. KrasG12D enhances surface TLR4 expression, sensitizing transformed cells to TLR4 ligands in the microenvironment, including the pancreatic microbiome. Collectively, our study describes a complex tumor-stromal interplay orchestrated by the TLR4-NLRP3-IL-1b signaling axis, which is critical for shaping the tumor microenvironment and driving pancreatic tumorigenesis.

Citation Format: Shipra Das, Sandra Vogt, Christina Hadju, Dafna Bar-Sagi. Regulation and function of IL-1b in immune modulation of pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B39.
Abstract B64: CD4 help is required for the generation of a transcriptionally distinct cytolytic CD8 T-cell subset to control chronic infection and tumor
Authors: Zander Ryan , Schauder David , Cui Weiguo
Published: June 2021

“CD4 help” is crucial to sustain the function of exhausted CD8 T cells, yet the detailed mechanisms by which CD4 help regulates CD8 T-cell differentiation and function during chronic viral infection remains elusive. Here, using single-cell RNA-sequencing (scRNA-seq) we show that CD8 T cells responding to chronic viral infection are more heterogeneous than previously appreciated, with three transcriptionally distinct subsets dominating the late phase of the antiviral response. Importantly, our findings uncover the formation of a previously unrecognized CD8 T-cell subset that exhibits potent cytolytic function. This subset is characterized by high expression of killer cell lectin-like receptors Klre1 and Klra9, the chemokine receptor CX3CR1, and the transcription factors T-bet and Zeb2. Notably, our data further demonstrate that the formation of this cytotoxic subset is critically dependent on CD4 help and that exploitation of this developmental pathway may be used therapeutically to enhance cytotoxic CD8 T-cell infiltration into the tumor. These findings uncover novel cellular and molecular mechanisms of how “CD4 help” regulates CD8 T-cell differentiation during persistent infection and have implications towards optimizing the generation of protective CD8 T cells in immunotherapy.

Citation Format: Ryan Zander, David Schauder, Weiguo Cui. CD4 help is required for the generation of a transcriptionally distinct cytolytic CD8 T-cell subset to control chronic infection and tumor [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B64.
Abstract B80: Frequency of tumor-reactive T cells in the blood of breast cancer patients and healthy donors
Authors: Pinho Mariana P. , Patente Thiago A. , Flatow Elizabeth A. , Barbuto José Alexandre M.
Published: June 2021

As cancer immunotherapy gains importance, the determination of a patient’s ability to react to his/her tumor is unquestionable. Though the presence of T cells that recognize specific tumor antigens is well established, the total frequency of tumor-reactive T cells in humans is difficult to assess, especially due to the lack of broad analysis techniques. Here, we describe a strategy that allows this determination using T-cell proliferation induced by tumor cell-lysate pulsed dendritic cells as the readout. The frequency of tumor-specific T cells was determined, in healthy donors and cancer patients, by challenging multiple wells containing a defined number of T cells with autologous monocyte-derived dendritic cells loaded with tumor lysates and assessing the wells with T-cell proliferation by CFSE dilution. It was possible to find CD4+ and CD8+ T cells specific for the lysate of the breast cancer cell lines MCF-7 (luminal), SK-BR-3 (Her2 subtype) and MDA-MB-231 (triple-negative) in the blood of most healthy donors. All healthy donors tested had tumor cell lines-reactive T cells for at least one of the cell lines, some, not only in the naive, but also in the memory compartment. Patients had higher frequencies of reactive T cells and, unexpectedly, this was not correlated to the frequency of tumor-reactive infiltrating T cells. The method showed here seems to be a robust and powerful strategy to evaluate the T-cell response against cancer, that has already helped to unveil some important aspects about the breast tumor-reactive T cell repertoire in humans, and opens the possibility of tracking T-cell repertoire changes along disease progression. Financial support: FAPESP (2014/25988-1).

Citation Format: Mariana P. Pinho, Thiago A. Patente, Elizabeth A. Flatow, José Alexandre M. Barbuto. Frequency of tumor-reactive T cells in the blood of breast cancer patients and healthy donors [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B80.
Abstract B81: Efficacy of nivolumab, pembrolizumab, and atezolizumab against MC38 colon cancer expressing human PD-1 in transgenic C57BL/6 mice expressing human PD-1 and PD-L1 checkpoint genes
Authors: Stackhouse Murray , Green Ted , Liu Jay , Hammond Charlotte , Durbin LaJuana , Chen Anna , Koratich Mike
Published: June 2021

The human checkpoint genes PD-1 and PD-L1 have been the target of extensive research for the treatment of human malignancies. Checkpoint inhibitor therapy has shown great promise in the clinic. Animal models that can use the human clinical antibodies will be beneficial for evaluating new therapies. A novel transgenic mouse model was developed that expresses the human PD-1 and PD-L1 in place of the murine genes. Additionally, a murine MC38 colon tumor cell line was modified to express human PD-L1. We evaluated the efficacy of human check point antibodies nivolumab, pembrolizumab, and atezolizumab in the transgenic animal model with modified MC38 colon cancer cells. Five hundred thousand transgenic MC38 cells were implanted in the C57BL/6 PD-1/PD-L1 knock in mice and allowed to grow for three days. The tumor-implanted mice were treated with nivolumab and pembrolizumab at 100 μg per animal and atezolizumab at 1 mg per animal on Days 3, 7, 10, and 14. Treatment with nivolumab and pembrolizumab caused tumor regression by Day 17. Growth inhibition was 84%, 58%, and 94% on Day 17 for nivolumab, atezolizumab, and pembrolizumab, respectively, compared to the control animals. There was no significant body weight loss and no signs of toxicity in any of the treated animals. We have shown that both PD-1 and PD-L1 inhibitors are effective in treating genetically modified MC38 colon tumors in transgenic mice. Further research will involve combining each of the checkpoint antibodies with various chemotherapeutic agents.

Citation Format: Murray Stackhouse, Ted Green, Jay Liu, Charlotte Hammond, LaJuana Durbin, Anna Chen, Mike Koratich. Efficacy of nivolumab, pembrolizumab, and atezolizumab against MC38 colon cancer expressing human PD-1 in transgenic C57BL/6 mice expressing human PD-1 and PD-L1 checkpoint genes [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B81.
Abstract B82: Distinct immune status in patients with adenocarcinoma and squamous cell carcinoma: Implication for immunotherapy of non-small cell lung cancer
Authors: Hradilova Nada , Palata Ondrej , Sadilkova Lenka , Mysikova Dagmar , Mrazkova Hana , Lischke Robert , Spisek Radek , Adkins Irena
Published: June 2021

Lung cancer is the leading cause of cancer mortality worldwide; therefore, understanding the biologic role of immune cell infiltrates in the tumor microenvironment is of eminent interest. In this study we compared immune cell populations, T-cell responses and secreted cytokines in primary tumors and nontumoral lung tissue from more than 40 adenocarcinomas (AC) and 40 squamous cell carcinomas (SCC) of non-small cell lung cancer (NSCLC) patients undergoing neoadjuvant surgery. Moreover, we compared immune-suppressive populations such as CD4+CD25+Foxp3+ T regulatory cells and myeloid-derived suppressor cells (MDSC) and the expression of immune checkpoint molecules PD-1, TIM3, LAG-3 and CTLA-4 in the blood of these patients. In both tumor subtypes we observed similarly higher infiltration of B cells, memory T cells, dendritic cells, NK cells, monocytes/macrophages, mast cells and CD4+CD25+Foxp3+ T regulatory cells compared to nontumoral tissue. However, immune cells seemed to be suppressed functionally more in SCC than AC as we detected significantly lower IFN-γ-positive T cells and production of proinflammatory cytokines after stimulation. PD-1, TIM3 and LAG-3 expression on T cells in blood and PD-1 on intratumoral CD8+ T cells of SSC patients were significantly elevated compared to AC patients. Similarly, the high number of MDSC, which correlated with Arginase 1 mRNA levels and downregulation of CD3zeta in T cells, was detected only in SCC. These results suggest that immune system of SSC patients might be subjected to a higher systemic and tumor-associated immune suppression than in AC patients. This should be taken into consideration in designing lung cancer immunotherapeutic approaches.

Citation Format: Nada Hradilova, Ondrej Palata, Lenka Sadilkova, Dagmar Mysikova, Hana Mrazkova, Robert Lischke, Radek Spisek, Irena Adkins. Distinct immune status in patients with adenocarcinoma and squamous cell carcinoma: Implication for immunotherapy of non-small cell lung cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B82.
Abstract B92: Landscape of B-cell immunity and related immune evasion in human cancers
Authors: Hu Xihao Sherlock , Zhang Jian , Liu Jun , Li Bo , Liu Xiaole Shirley
Published: June 2021

Tumor-infiltrating B cell is an important component in the microenvironment with unclear antitumor impacts. We enhanced our previous computational algorithm TRUST to extract the B cell immunoglobulin (Ig) hypervariable regions from bulk tumor RNA-seq data. TRUST assembled over 30 million complementarity-determining region 3 (CDR3s) of the B-cell heavy chain (IgH) from The Cancer Genome Atlas (TCGA). Widespread B-cell clonal expansions and Ig subclass switch events were observed in diverse human cancers. Prevalent somatic copy number alterations (SCNA) in MICA/B genes related to antibody-dependent cell mediated cytotoxicity (ADCC) were identified in tumors with elevated B-cell activity. IgG3-1 subclass switch interacts with the B cell receptor affinity maturation and defects in the ADCC pathway. The comprehensive pan-cancer analyses of tumor-infiltrating B-cell receptor repertoires revealed novel tumor immune evasion mechanism through genetic alterations. The IgH sequences identified in this work are potentially useful resources for future development of immunotherapies.

Citation Format: Xihao Sherlock Hu, Jian Zhang, Jun Liu, Bo Li, Xiaole Shirley Liu. Landscape of B-cell immunity and related immune evasion in human cancers [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B92.
Abstract IA11: The LXR/ApoE pathway regulates the innate immune system in cancer
Authors: Tavazoie Masoud
Published: June 2021

Harnessing of the adaptive immune system, either by adoptive transfer of engineered T cells or by direct activation of endogenous T cells via checkpoint blockade, has yielded unprecedented clinical benefit in cancer. However, the full potential of these therapies is hampered by a system of elaborate molecular and cellular mechanisms that tumors orchestrate as they evolve to evade T-cell attack during metastatic cancer progression. These mechanisms, collectively referred to as the immune-suppressive tumor microenvironment, rely on cancer co-opting signaling pathways that regulate immunity in noncancer settings, including those implicated in normal physiology or in other disease states. Using an unbiased experimental approach to identify key drivers of cancer metastasis, apolipoprotein E (ApoE) was revealed as a regulator of cancer progression and tumor immunity. As tumors grow and metastasize, ApoE expression becomes silenced via the activity of a group of microRNAs that become switched on during cancer progression. The silencing of ApoE expression in tumors is associated with significantly greater metastatic potential, worse clinical prognosis, and increased accumulation of innate immunosuppressive myeloid cells known as myeloid-derived suppressor cells (MDSCs). The ApoE pathway has previously been associated with the pathophysiology of atherosclerosis and Alzheimer’s disease, both of which are characterized histologically, in part, by aberrant inflammatory myeloid cell accumulation in the form of myeloid-derived foam cells and myeloid-derived microglia, respectively. In cancer, MDSCs accumulate in tumors and in the circulation, where they inhibit the activity of cytotoxic T cells via the expression of multiple immunosuppressive molecules. Their high abundance in the circulation has been associated with resistance to checkpoint blockade, highlighting their clinical relevance. MDSC abundance was found to be regulated via ApoE signaling through the ApoE receptor LRP8. Therapeutic activation of silenced ApoE expression can be accomplished pharmacologically by the administration of Liver X Receptor (LXR) agonists, which drive ApoE expression transcriptionally. RGX-104, a potent and selective LXR agonist, reversed cancer immune evasion in tumor models and in advanced cancer patients harboring a diverse array of refractory malignancies, including checkpoint inhibitor-refractory cancers. RGX-104 rapidly depleted MDSCs, resulting in restoration of antitumor immunity via activation of PD-1+ CD8+ T cells, which ultimately resulted in clinical antitumor activity.

Citation Format: Masoud Tavazoie. The LXR/ApoE pathway regulates the innate immune system in cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr IA11.
Abstract IA17: Molecular mechanisms of T-cell exhaustion and implications for immunotherapy
Authors: Wherry E. John
Published: June 2021

T-cell exhaustion is common during chronic infections and cancer and prevents optimal immunity. Exhausted CD8 T cells (TEX) are defined by the loss of ability to perform effector functions efficiently, low proliferative capacity, and poor survival following antigen stimulation. TEX also co-express multiple inhibitory receptors that negatively regulate their function. Indeed, receptors such as PD-1 have become major targets of clinical immunotherapies in cancer and infectious disease aimed at reinvigorating TEX. Despite the clinical success of PD-1-based therapies in human melanoma and other cancers, the majority of patients do not have durable clinical benefit from anti-PD-1 monotherapy. A major challenge remains identifying which patients will respond to anti-PD-1 therapy and defining the underlying mechanisms for successful, durable response versus treatment failure. Detailed immune profiling of peripheral blood from stage IV melanoma patients before and after pembrolizumab (pembro) identified reinvigoration in circulating TEX. These data indicated that nearly 80% of patients experienced a strong, on-target immunologic effect of PD-1 blockade. However, the objective clinical response rate in this cohort was less than 40% and reinvigoration of circulating TEX alone did not predict clinical outcomes. We are currently now using neoadjuvant clinical trial designs and preclinical models to dissect the molecular and mechanistic features of effective and ineffective responses to checkpoint blockade and to understand the underlying molecular program of exhausted CD8 T cells. Our emerging data not only provide a framework for dissecting distinct types of treatment failures in melanoma and have implications for stratifying patients into additional immunotherapeutic treatment approaches, but also point to key underlying molecular pathways involved in programming and controlling the developmental biology of exhausted T cells. The implications of these findings for clinical therapies will be discussed.

Citation Format: E. John Wherry. Molecular mechanisms of T-cell exhaustion and implications for immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr IA17.
Abstract IA21: From the clinic to the lab: Investigating response and resistance mechanisms to immune checkpoint therapy
Authors: Sharma Padmanee
Published: June 2021

Immune checkpoint therapies, including anti-CTLA-4, anti-PD-1 and anti-PD-L1, have led to significant clinical responses in cancer patients. To investigate immunologic changes and mechanistic pathways that are elicited by these therapies, we conducted presurgical and tissue-based clinical trials, which permit access to tumor tissues for laboratory studies. To compare and contrast data, we chose one tumor type that responds well to immune checkpoint therapy and one that does not. The first presurgical trial was conducted with anti-CTLA-4 (ipilimumab) in a cohort of patients with localized bladder cancer. The second presurgical trial was conducted with anti-CTLA-4 (ipilimumab) in patients with localized prostate cancer. In addition, we evaluated data from patients with melanoma who received immune checkpoint therapy. These data enabled us to identify the ICOS/ICOSL pathway as relevant for antitumor immune responses in the setting of anti-CTLA-4 therapy. We also identified resistance mechanisms including expression of other immune inhibitory pathways, such as VISTA, and loss of the IFNγ signaling pathway in tumor cells. These data will be discussed in greater details.

Citation Format: Padmanee Sharma. From the clinic to the lab: Investigating response and resistance mechanisms to immune checkpoint therapy [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr IA21.
Abstract IA26: Dynamic interactions between myeloid and lymphoid cells regulate response to therapy in solid tumors
Authors: Coussens Lisa M.
Published: June 2021

The concept that leukocytes are critical components of solid tumors is now generally accepted; however, their role(s) in regulating aspects of neoplastic progression, and/or response to cytotoxic, targeted, and/or immune therapy is only beginning to be understood. Utilizing de novo mouse models of organ-specific solid tumor development (mammary, cutaneous, and pancreas carcinomas and mesothelioma), we now appreciate that adaptive leukocytes differentially regulate myeloid cell recruitment, activation, and effector function, and in turn, activated tumor-infiltrating myeloid cells engage tissue-based programs to foster malignancy and repress antitumor immunity by a diversity of mechanisms. Treatment of tumor-bearing mice with therapeutic agents that disrupt lymphocyte-myeloid cell interaction, myeloid cell activation, or myeloid cell functionality generally slows primary tumor growth kinetics when combined with cytotoxic therapy; however, their impact on metastases is variable. Similar to organ-specific regulatory programs co-opted to foster primary tumor growth, regulation of metastatic seeding and outgrowth is also regulated by tissue- and organ-specific mechanisms. Based on this, it stands to reason that therapeutic strategies may not be efficacious in both primary and metastatic locations. To be presented will be our recent insights into organ- and tissue-specific regulation of primary and metastatic cancer development by adaptive and innate immune cells, how systemic regulation of humoral immunity and complement-mediated pathways regulate pro- versus antitumor immune responses, and new studies evaluating how attenuating protumor properties of select lymphoid and myeloid cells can be exploited to enhance therapeutic responses to cytotoxic and immune-based therapy.

LMC acknowledges generous support from the NIH/NCI, the Department of Defense Breast Cancer Research Program Era of Hope Scholar Expansion Award, Susan G. Komen Foundation, the Breast Cancer Research Foundation, the Brenden-Colson Center for Pancreatic Health, and a Stand Up To Cancer-Lustgarten Foundation Pancreatic Cancer Convergence Dream Team Translational Research Grant.

Citation Format: Lisa M. Coussens. Dynamic interactions between myeloid and lymphoid cells regulate response to therapy in solid tumors [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr IA26.
Abstract PR08: Discovery of immune regulators in primary human T cells using genome-wide CRISPR screens
Authors: Carnevale Julia , Shifrut Eric , Tobin Victoria , Roth Theodore , Woo Jonathan , Bui Christina , Li Jonathan , Diolaiti Morgan , Ashworth Alan , Marson Alexander
Published: June 2021

The incredible success of cancer immunotherapies is still only limited to subsets of patients, which has motivated efforts to discover novel therapeutic targets to boost tumor killing by effector T cells. However, the translational potential of these discoveries may be limited by suboptimal correlation between cell line and animal models with human disease. Further, the majority of unbiased screening approaches are performed in cancer cells lines, rather than in the effector T cells themselves. We have developed a novel and flexible screening platform using sgRNA lentiviral infection with Cas9 protein electroporation (SLICE), to perform genome-wide CRISPR screens in primary human T cells at genome-wide scale. We have used this platform to survey the response of primary human CD8+ T cells to TCR stimulation. This screen revealed essential components of TCR signaling and inhibitors/agonists of T-cell proliferation. Targeted deletion of top candidate genes from the screen led to increased proliferation, increased expression of activation markers, and improved tumor killing in in vitro co-culture models. Coupling our screening platform with single-cell RNA-seq identified functional clustering of cell states across perturbations and showed that pooled screens in primary cells can now be analyzed at a single-cell level. In addition to finding ways to boost intrinsic T-cell activation, we also sought to adapt the SLICE screening platform to identify mediators of resistance to immunosuppressive forces in the tumor microenvironment. To model one such suppressive factor, we performed the screen in the presence of a potent adenosine agonist and found known and novel regulators of adenosine signaling in T cells. We are further integrating this platform with a two-cell co-culture system to attempt to find mechanisms of resistance to immunosuppressive cells in the tumor microenvironment. This novel platform provides the framework for unbiased, large-scale discovery of immune regulators as potential therapeutic targets in primary human T cells.

This abstract is also being presented as Poster A90.

Citation Format: Julia Carnevale, Eric Shifrut, Victoria Tobin, Theodore Roth, Jonathan Woo, Christina Bui, Jonathan Li, Morgan Diolaiti, Alan Ashworth, Alexander Marson. Discovery of immune regulators in primary human T cells using genome-wide CRISPR screens [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr PR08.
Abstract PR11: Tumor cell-intrinsic factors underlie the heterogeneity of immune infiltration and response to immunotherapy in pancreatic cancer
Authors: Li Jinyang , Byrne Katelyn T. , Yan Fangxue , Yamazoe Taiji , Chen Zeyu , Baslan Timour , Richman Lee P. , Lin Jeffrey , Sun Yu H. , Liudahl Shannon M. , Tobias John W. , Lowe Scott , Coussens Lisa M. , Wherry John E , Vonderheide Robert H. , Stanger Ben Z.
Published: June 2021

Intertumoral heterogeneity—the biologic and functional differences among different individual tumors—poses a challenge for immunotherapy. To understand the tumor cell-intrinsic factors underlying the heterogeneity of tumor immunity and sensitivity to immunotherapy, we established a new experimental system by generating a library of congenic pancreatic tumor cell clones from a genetic mouse model driven by mutant Kras and p53. These tumor cell clones robustly formed implanted tumors that recapitulated the T cell-inflamed and non-T cell-inflamed tumor microenvironments in human patients, associated with distinct patterns of infiltration by T cells and myeloid cells. We found that the non-T cell-inflamed phenotype was dominant over the T cell-inflamed phenotype in the local tumor microenvironment. Both quantitative and qualitative features, specifically expression of markers of prior TCR activation, of intratumoral CD8+ T cells predicted the response to immunotherapies. An integrated transcriptomic and epigenetic analysis revealed that tumor cell-intrinsic expression of the chemokine CXCL1 as a major determinant of the non-T cell-inflamed microenvironment, and ablation of tumor cell-intrinsic CXCL1, promoted T-cell infiltration and sensitivity to a combination of chemotherapies, CD40 agonist, and checkpoint blockades. These results demonstrated that heterogeneity of tumor immune phenotypes is driven by tumor cell-intrinsic factors that can be manipulated to influence the outcome of immunotherapies. The observation that non-T cell-inflamed phenotype is dominant emphasized the importance of targeting mechanisms driving T-cell low phenotype for improving immunotherapy response. This experimental system will provide opportunities for understanding other aspects of tumor heterogeneity as well.

This abstract is also being presented as Poster A45.

Citation Format: Jinyang Li, Katelyn T. Byrne, Fangxue Yan, Taiji Yamazoe, Zeyu Chen, Timour Baslan, Lee P. Richman, Jeffrey Lin, Yu H. Sun, Shannon M. Liudahl, John W. Tobias, Scott Lowe, Lisa M. Coussens, John E Wherry, Robert H. Vonderheide, Ben Z. Stanger. Tumor cell-intrinsic factors underlie the heterogeneity of immune infiltration and response to immunotherapy in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr PR11.
Relationship between Monocytes and Stenosis-Related Autologous Arteriovenous Fistula Dysfunction
Authors: Li Caifang , Li Qiang , Ou Jingyun , Li Weilong , Guan Baozhang , Lu Yongping , Yun Chen , Hocher Berthold , Hu Bo , Yin Lianghong
Published: June 2021

Background: Arteriovenous fistula (AVF) is considered to be the best choice of vascular access, but the maturation rate and patency rate of AVF are not satisfactory. Many studies have explored the influencing factors of AVF failure but do not involve the direct relationship between monocyte count and AVF failure. This study aims to explore the relationship between monocyte count and AVF dysfunction related to stenosis. Methods: From September 2017 to September 2018, basic clinical data and laboratory parameters of patients were collected. All included patients were followed up to September 2019. The stenosis-related AVF failure events that occurred after the patient included in the study and the time of their occurrence were recorded. All patients were divided into 3 groups based on the tertile of monocyte count. Kaplan-Meier method was used to compare the patency rate of AVF in each group. The effects of variables on AVF failure were analyzed. A multivariate Cox regression model with p < 0.05 was included in the univariate Cox regression analysis. Results: A total of 120 patients were included in this study. According to the recorded baseline monocyte count levels, they were divided into 3 groups according to their tertiles, 34 cases in the T1 group (T1 < 0.32 × 109/L), 44 cases in the T2 group (0.32 ≤ T2 < 0.51 × 109/L), and 42 cases in T3 group (T3 ≥0.51 × 109/L). After a median follow-up of 20 months, a total of 31 AVF failure events occurred. Kaplan-Meier survival curves showed that patients with a baseline monocyte count ≥0.51 × 109/L had the lowest patency rate of AVF (log-rank test χ2 = 7.525, p = 0.023). After adjusting to basic clinical data and biochemical indicators, there were statistically significant differences in patency rates of the 3 groups (hazard ratio = 2.774, 95% CI = 1.092–7.043). Conclusion: Monocyte count ≥0.51 × 109/L is an independent risk factor for AVF failure, and AVF failure caused by monocytes may be driven by inflammation.
An 88.8-kb Novel Deletion of 19q13.2 Encompassing the ATP1A3Gene Detected by Array CGH in a Patient with Delayed Psychomotor Development, Generalized Hypotonia and Macrocephaly
Authors: García-Payá Elena , Gutiérrez-Agulló María , García-Prieto Francisco F. , Francés Ferre Jorge
Published: June 2021

Many neurodevelopmental disorders are caused by the presence of CNVs. Chromosome microarray technology is widely used to accurately detect CNVs. We report the case of a male, aged 3 years, presenting with delayed psychomotor development, generalized hypotonia, encephalopathy, delayed myelination in the central nervous system, and poor motor coordination. The array CGH revealed an interstitial deletion of chromosome 19q13.2 with a size of 88.8 kb involving 3 OMIM genes: RABAC1, ARHGEF1, and ATP1A3. Heterozygous mutations in the ATP1A3 gene are associated with delayed psychomotor development, alternating hemiplegia of childhood type 2 (AHC2), dystonia type 12, and cerebellarataxia-areflexia–pes cavus-optic atrophy-sensorineural hearing loss syndrome, also called CAPOS syndrome. The phenotypic expression of partial ATP1A3 deletion is, however, poorly described in the literature. The deletion was confirmed by MLPA, and we identified a hitherto undescribed novel deletion of exons 3b–21 of the ATP1A3 gene. Our data suggest that the deletion of the ATP1A3 gene is a causative factor of the AHC2 phenotype in the patient.
Ischemic Stroke in a 29-Year-Old Patient with COVID-19: A Case Report
Authors: Avvantaggiato Christian , Amoruso Loredana , Lo Muzio Maria Pia , Mimmo Maria Assunta , Delli Bergoli Michelina , Cinone Nicoletta , Santoro Luigi , Stuppiello Lucia , Turitto Antonio , Ciritella Chiara , Fiore Pietro , Santamato Andrea
Published: June 2021

Increasing evidence reports a greater incidence of stroke among patients with Coronavirus disease 2019 (COVID-19) than the non-COVID-19 population and suggests that SARS-CoV-2 infection represents a risk factor for thromboembolic and acute ischemic stroke. Elderly people have higher risk factors associated with acute ischemic stroke or embolization vascular events, and advanced age is strongly associated with severe COVID-19 and death. We reported, instead, a case of an ischemic stroke in a young woman during her hospitalization for COVID-19-related pneumonia. A 29-year-old woman presented to the emergency department of our institution with progressive respiratory distress associated with a 2-day history of fever, nausea, and vomiting. The patient was transferred to the intensive care unit (ICU) where she underwent a tracheostomy for mechanical ventilation due to her severe clinical condition and her very low arterial partial pressure of oxygen. The nasopharyngeal swab test confirmed SARS-CoV-2 infection. Laboratory tests showed neutrophilic leucocytosis, a prolonged prothrombin time, and elevated D-dimer and fibrinogen levels. After 18 days, during her stay in the ICU after suspension of the medications used for sedation, left hemiplegia was reported. Central facial palsy on the left side, dysarthria, and facial drop were present, with complete paralysis of the ipsilateral upper and lower limbs. Computed tomography (CT) of the head and magnetic resonance imaging of the brain confirmed the presence of lesions in the right hemisphere affecting the territories of the anterior and middle cerebral arteries, consistent with ischemic stroke. Pulmonary and splenic infarcts were also found after CT of the chest. The age of the patient and the absence of serious concomitant cardiovascular diseases place the emphasis on the capacity of SARS-CoV-2 infection to be an independent cerebrovascular risk factor. Increased levels of D-dimer and positivity to β2-glycoprotein antibodies could confirm the theory of endothelial activation and hypercoagulability, but other mechanisms – still under discussion – should not be excluded.
Efficacy and Safety of Plastic Cannulae Compared with Metal Needles in the Initial Use of an Arteriovenous Fistulae in Incident Hemodialysis Patients: A Randomized Controlled Study
Authors: Choi Yong Seon , Lee Hyung Seok , Joo Narae , Park Pyoungju , Cho Seung Nam , Youn In Ju , Song Young Rim , Kim Sung Gyun , Kim Jwa-Kyung
Published: June 2021

Introduction: Successful cannulation of an arteriovenous fistula (AVF) is important in patients starting hemodialysis (HD). Metal needles have been used for decades, but the usefulness of plastic cannulae has recently been demonstrated as a new technique. Methods: This was a prospective, randomized, open-label study of incident HD patients. Eligible patients were randomized into 2 groups in a 1:1 ratio (n = 45/group). Maturation of the AVF was confirmed using Doppler ultrasound prior to first needling, and 2 well-trained nurses implemented the AVF cannulation. The primary endpoint was the initial cannulation failure rate, defined as the failure of successful completion of 3 consecutive dialysis sessions. The secondary endpoints were time for hemostasis at the end of HD, degree of patients’ pain, degree of cannulation difficulty felt by the nursing staffs, and achieving optimal HD adequacy. Results: The mean elapsed time from AVF creation to the first cannulation was 48.1 ± 16.7 days. A total of 17 cases of cannulation failure occurred, and the failure risk tended to be higher in the metal needle group than the plastic cannula group (hazard ratio 2.6, 95% confidence interval 0.95–7.41) after adjusting for age, gender, comorbidities, and AVF location. The overall incidence of vessel injury was higher and time for hemostasis was significantly longer in the metal group than the plastic group. The use of plastic cannula was associated with a better HD adequacy compared to a metal needle. However, the patients’ pain score (p = 0.004) and nursing staff’s cannulation difficulty score (p = 0.084) were higher in the plastic group, emphasizing the great importance of practice using plastic cannulae. Conclusion: The vascular outcomes of plastic cannulae were much favorable compared to metal needles in incident HD patients. The use of plastic cannulae could be a new and innovative way to improve the quality of dialysis.
Impact of Physician Training Level on Neonatal Tracheal Intubation Success Rates and Adverse Events: A Report from National Emergency Airway Registry for Neonates (NEAR4NEOS)
Authors: Johnston Lindsay , Sawyer Taylor , Ades Anne , Moussa Ahmed , Zenge Jeanne , Jung Philipp , DeMeo Stephen , Glass Kristen , Singh Neetu , Howlett Alexandra , Shults Justine , Barry James , Brei Brianna , Foglia Elizabeth , Nishisaki Akira ,   for the NEAR4NEOS Investigators
Published: June 2021

Introduction: Neonatal tracheal intubation (TI) outcomes have been assessed by role, but training level may impact TI success and safety. Effect of physician training level (PTL) on the first-attempt success, adverse TI-associated events (TIAEs), and oxygen desaturation was assessed. Methods: Prospective cohort study in 11 international NEAR4NEOS sites between October 2014 and December 2017. Primary TIs performed by pediatric/neonatal physicians were included. Univariable analysis evaluated association between PTL, patient/practice characteristics, and outcomes. Multivariable analysis with generalized estimating equation assessed for independent association between PTL and outcomes (first-attempt success, TIAEs, and oxygen desaturation ≥20%; attending as reference). Results: Of 2,608 primary TIs, 1,298 were first attempted by pediatric/neonatal physicians. PTL was associated with patient age, weight, comorbidities, TI indication, difficult airway history, premedication, and device. First-attempt success rate differed across PTL (resident 23%, fellow 53%, and attending 60%; p < 0.001). There was no statistically significant difference in TIAEs (resident 22%, fellow 20%, and attending 25%; p = 0.34). Desaturation occurred more frequently with residents (60%), compared to fellows and attendings (46 and 53%; p < 0.001). In multivariable analysis, adjusted odds ratio of the first-attempt success was 0.18 (95% CI: 0.11–0.30) for residents and 0.80 (95% CI: 0.51–1.24) for fellows. PTL was not independently associated with adjusted odds of TIAEs or severe oxygen desaturation. Conclusion: Higher PTL was associated with increased first-attempt success but not TIAE/oxygen desaturation. Identifying strategies to decrease adverse events during neonatal TI remains critical.