bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract TMIM-077: MYXOMA VIRUS ENHANCES TREATMENT BENEFIT OF CHEMOTHERAPY AND DENDRITIC CELL IMMUNOTHERAPY IN OVARIAN CANCER PRECLINICAL MODEL
Authors: Conrad Steven J , Nounamo Bernice , Cannon Martin , Liu Jia
Published: June 2021

Myxoma virus (MYXV) is a poxvirus with oncolytic and immunotherapeutic potential in many cancer models, including ovarian cancer (OC). Moreover, MYXV synergizes with chemotherapy including cisplatin for OC treatment. In this study, we used a p53-/- ID8 mouse model that closely portrays human high-grade serous OC to test MYXV virotherapy. We combined MYXV regime with cisplatin treatment and an innovative Th17-inducing dendritic cell (Th17-DC) vaccine currently being tested in clinical trials with OC patients. For DC immunotherapy, bone marrow-derived DC were pulsed with peptides from Sp17, a cancer testis antigen highly expressed in human OC and the ID8 mouse model. For MYXV virotherapy, we examined both wild-type and a replication-defective MYXV that is engineered without an essential viral immunomodulator called M062 (M062R-null MYXV). We found that inoculation with replication-competent MYXV improves survival when administered before cisplatin therapy. Interestingly, when the replication-defective M062R-null MYXV was used, improved survival was observed with virotherapy after the cisplatin treatment. We further found that M062R-null MYXV treatment provided long-lasting survival in combination with cisplatin and Th17-DC immunotherapy. Related studies showed that M062R-null MYXV infection in murine and primary human OC cells stimulated robust type I IFN expression and pro-inflammatory cytokines. Moreover, M062R-null MYXV activates type I IFN in macrophages and expression of inflammatory cytokines (e.g., CXCL-10 and IL-6). In conclusion, we propose that MYXV virotherapy provokes a type I interferon response and inflammatory cytokines that modulate the tumor microenvironment and enhance protective immune responses to Th17-DC vaccination for OC treatment.

Citation Format: Steven J Conrad, Bernice Nounamo, Martin Cannon, Jia Liu. MYXOMA VIRUS ENHANCES TREATMENT BENEFIT OF CHEMOTHERAPY AND DENDRITIC CELL IMMUNOTHERAPY IN OVARIAN CANCER PRECLINICAL MODEL [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr TMIM-077.
Abstract A25: Hectd3 protects against colitis and colon cancer development through maintenance of homeostatic immune environment in the gut
Authors: Zuniga Ashley , Parthasarath Upasana , Cho Jonathan , Drashansky Theodore , Helm Eric , Lorentsen Kyle , He Zhen , Jobin Christian , Avram Dorina
Published: June 2021

Colorectal cancer (CRC) remains one of the most common and deadliest malignancies in USA, including in Florida. CRC includes hereditary, sporadic, and colitis-associated cancer (CAC). CAC often shows rapid progression, poor response to treatment, and high mortality. In CAC, tumors are formed in the context of chronic inflammation, but ultimately the immune populations in colonic tumors acquire a suppressive phenotype. Among such populations, myeloid-derived suppressive cells (MDSCs), consisting of polymorphonuclear (PMN)-MDSCs and monocytic (M)-MDSCs, accumulate in the tumors and promote a tumor-suppressive microenvironment, together with tumor-associated macrophages. Numerous questions remain unanswered in regard to the biology and regulation of myeloid-suppressive populations in CAC. We found that the levels of the ubiquitin ligase Hectd3 were reduced in human inflamed ulcerative colitis (UC) tissues and in colonic tumors versus healthy matched colonic tissues. Hectd3 KO mice developed more severe dextran sodium sulfate (DSS)-induced colitis and larger and more numerous colonic tumors in the azoxymethane (AOM)/DSS model of CAC. Bone marrow chimera experiments demonstrated that both the hematopoietic and nonhematopoietic compartments play roles in the phenotype, in DSS colitis and in AOM/DSS CAC model. During DSS-induced colitis we found that genes for several proinflammatory cytokines were upregulated in the colons of Hectd3 KO mice, including IL6, IL11 and G-CSF, as well for Lipocalin-2, associated with inflammation. However, in the colonic tumors of Hectd3 KO mice, the CD11b+ CD11c- myeloid cells were elevated and showed increased Arginase 1 and iNOS levels and frequencies, suggestive of a suppressive phenotype. We hypothesize that absence of Hectd3 promotes a highly inflammatory phenotype in the colon, and further an immune-suppressive phenotype in the colonic tumors through regulation of specific signaling pathways in myeloid populations.

Citation Format: Ashley Zuniga, Upasana Parthasarath, Jonathan Cho, Theodore Drashansky, Eric Helm, Kyle Lorentsen, Zhen He, Christian Jobin, Dorina Avram. Hectd3 protects against colitis and colon cancer development through maintenance of homeostatic immune environment in the gut [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 A25.
Abstract A44: High-efficiency electroporation of nonexpanded T cells and NK cells for CAR-T and CAR-NK
Authors: Chen Jian , Xia Xiaofeng
Published: June 2021

CAR-T cells are currently manufactured for clinical use by infection of human T cells with viral vectors containing the CAR gene. T lymphocytes have to be stimulated and expanded ex vivo because the viral vectors infect fresh natural lymphocytes very poorly. NK cells are also commonly expanded ex vivo before they are subject to electroporation. Possibly influenced by virus infection protocols, T cell and NK cell electroporation is often done after they are ex vivo expanded. We developed a novel electroporation technology that corrected many physics mistakes in the field. We can now achieve very high transfection efficiency for fresh T cells while maintaining cell survival. For Sleeping Beauty transposon-based CAR expression, we found that over a period of two to three weeks the efficiency can get to 60% to 90% with fast cell proliferation. The protein expression time after electroporation is very short. For simple GFP plasmids we can observe GFP expression after only 30 minutes. Similarly, for NK cells, we were able to achieve 42% transfection efficiency with fresh nonexpanded NK cells. We further compared post-electroporation cell proliferation potential between nonexpanded fresh T cells and stimulated/expanded T cells. It turned out that although fresh T cells are smaller in volume, they are much better than expanded T cells in survival after electroporation. Expanded NK cells also showed much higher cytotoxicity than fresh NK cells after electroporation. With our new electroporation technology, CAR-T and CAR-NK can now be manufactured quicker and better. Our new protocols focusing on fresh T cells and fresh NK cells would be a great help for the field.

Citation Format: Jian Chen, Xiaofeng Xia. High-efficiency electroporation of nonexpanded T cells and NK cells for CAR-T and CAR-NK [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 A44.
Abstract A47: The immunoproteosome mediates resistance to natural killer cell killing
Authors: Pasion Joyce , Wendel Hans Guido
Published: June 2021

We identified the immunoproteosome as a mediator of resistance to natural killer (NK) cell killing through a genome-wide activation CRISPR screen. The immunoproteosome is a modified proteolytic complex composed of a catalytic 20S core and a regulatory 11S component. An essential function of the immunoproteosome is to degrade intracellular proteins that are eventually presented as antigens on the cell surface by the major histocompatibility complex (MHC) I. We validated several subunits that play a critical role in regulating responses to NK cells, specifically, PSMA1, PSMB6 and PSME1, which encode the alpha subunit of the 20S catalytic proteosome, the beta subunit of the 20S proteosome, and the alpha subunit of the 11S regulator, respectively. While several studies have reported that proteasome inhibitors sensitize cancer cells to NK cell killing, the exact mechanisms of these inhibitors are not well understood. Our data indicate that these proteasome components may be attractive targets to improve cancer cell response to NK cell-based therapies.

Note: This abstract was not presented at the conference.

Citation Format: Joyce Pasion, Hans Guido Wendel. The immunoproteosome mediates resistance to natural killer cell killing [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 A47.
Abstract A68: A casein kinase 2 inhibitor disorders myeloid cell differentiation by blocking CCAAT/enhancer-binding protein-alpha signaling pathway in tumor microenvironment
Authors: Hashimoto Ayumi , Gao Chan , Mastio Jerome , Kossenkov Andrew , Abrams Scott I. , Purandare Ashok V. , Desilva Heshani , Wee Susan , Hunt John , Jure-Kunkel Maria , Gabrilovich Dmitry I.
Published: June 2021

Myeloid cells are major components of the tumor microenvironment, which are known to suppress antitumor immunity. Casein kinase 2 (CK2), a serine/threonine protein kinase with diverse intracellular protein substrates, regulates several signaling pathways involved in tumor progression and cell differentiation. We examined the efficacy of a novel CK2 inhibitor on modulating the myeloid cells in the tumor microenvironment. Although CK2 inhibitors BMS-595 and BMS-211 moderately inhibited the tumor growth in LLC, 4T1, MC38 and CT26 tumor-bearing mice, these inhibitors drastically enhanced the antitumor efficacy of anti-CTLA4 antibody with 60% to 90% of complete rejection. Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) and macrophages in spleens, and tumor-associated macrophages (TAM) were found to be decreased in LLC tumor-bearing mice treated with BMS-595 for 2 weeks. Murine hematopoietic progenitor cells (HPC) from bone marrow and human progenitor cells from cord blood were cultured with BMS-595 to evaluate the differentiation. BMS-595 treatment dramatically decreased the proportion of granulocytic cells, and this decrease was not caused by the direct killing nor apoptosis. Therefore, the genes regulated by transcription factors, IRF8, C/EBPα and C/EBPβ, which are involved in PMN-MDSC differentiation, were evaluated. Many genes controlled by C/EBPα were downregulated by the BMS-595 treatment in HPCs. Active p42 subunit of C/EBPα was revealed to be reduced by the BMS-595 treatment in HPCs, which are inversely correlated with the increased level of dominant negative p30 subunit of C/EBPα, in both the cytoplasm and nucleus of HPCs. Our results suggest that CK2 inhibition leads to a reduction of immune-suppressive PMN-MDSC and TAM by inhibiting C/EBPα activity, resulting in an enormous augmentation of antitumor efficacy of immunotherapy.

Citation Format: Ayumi Hashimoto, Chan Gao, Jerome Mastio, Andrew Kossenkov, Scott I. Abrams, Ashok V. Purandare, Heshani Desilva, Susan Wee, John Hunt, Maria Jure-Kunkel, Dmitry I. Gabrilovich. A casein kinase 2 inhibitor disorders myeloid cell differentiation by blocking CCAAT/enhancer-binding protein-alpha signaling pathway in tumor microenvironment [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 A68.
Abstract A73: Human granulocytic myeloid-derived suppressor cells (G-MDSCs) in metastatic breast cancer patients is a heterogeneous population with angiogenic potential in vivo
Authors: Mehmeti Meliha , Bergenfelz Caroline , Bexell Daniel , Carlsson Robert , Hellsten Rebecka , Larsson Anna-Maria , Loman Niklas , Riesbeck Kristian , Ahl Jonas , Rydberg-Millrud Camilla , Paul-Visse Gesine , Rydén Lisa , Killander Fredrika , Leandersson Karin
Published: June 2021

MDSCs are potent immunosuppressive myeloid cells that have been implicated in various diseases, including cancer. In humans, MDSCs are divided into Mo-GMDSCs and G-MDSCs subgroups, depending on their surface phenotype and function. While their immunosuppressive properties have been extensively studied, knowledge about their origin and their tumor-promoting functions per se remains scarce. In this study, we demonstrate that G-MDSCs are significantly enriched in the peripheral blood of locoregional recurrent metastatic breast cancer (LRR/MBC) compared to healthy donors. The G-MDSCs display a heterogeneous population with a morphology representing one blast-like and one polymorphonuclear (PMN) population. In a breast cancer xenograft model, co-transplanting G-MDSCs sorted from LRR/MBC together with breast cancer cells significantly promoted angiogenesis and tumor growth. Gene expression profiling analysis revealed that G-MDSCs from LRR/MBC rather clustered with neutrophils from healthy donors, sharing similar expression in genes relevant for angiogenesis, lymphangiogenesis and immunosuppression, but surprisingly not with G-MDSCs from sepsis patients. We conclude that enrichment of G-MDSCs in metastatic breast cancer represents a heterogeneous population of activated neutrophils that can promote angiogenesis and tumor progression, and immature blasts of yet unknown character.

Citation Format: Meliha Mehmeti, Caroline Bergenfelz, Daniel Bexell, Robert Carlsson, Rebecka Hellsten, Anna-Maria Larsson, Niklas Loman, Kristian Riesbeck, Jonas Ahl, Camilla Rydberg-Millrud, Gesine Paul-Visse, Lisa Rydén, Fredrika Killander, Karin Leandersson. Human granulocytic myeloid-derived suppressor cells (G-MDSCs) in metastatic breast cancer patients is a heterogeneous population with angiogenic potential in vivo [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 A73.
Abstract A74: Cytomegalovirus infection of melanoma delays tumor growth by recruiting and altering monocytic phagocytes in the tumor
Authors: Wilski Nicole A. , Del Casale Christina , Alexeev Vitali , Daskalakis Constantine , Purwin Timothy J. , Aplin Andrew E. , Snyder Christopher M.
Published: June 2021

Herpesvirus-based immunotherapies are emerging as exciting new possibilities for vaccines and cancer treatment. We have been exploring the use of a cytomegalovirus (CMV)-based cancer therapy to promote productive tumor-specific immunity and modify the tumor microenvironment. We previously showed that intratumoral (IT) infections with murine (M)CMV led to significant delays in the growth of B16 melanomas that were, surprisingly, independent of vaccine antigens encoded in the viral backbone. Although MCMV could infect B16 cells directly in vitro, tumor-associated macrophages (TAMs) were a primary target for viral infection in vivo. To test the mechanistic role of TAMs, we depleted monocytic phagocytes with clodronate. Loss of these myeloid cells completely prevented MCMV from delaying tumor growth. Macrophages are well-known targets of MCMV infection and in vitro studies demonstrated that MCMV infection of M2-polarized macrophages resulted in repolarization to an M1-like phenotype. In vivo, MCMV infection also increased expression of several inflammatory cytokines in the tumor. In a natural infection, MCMV uses the chemokine MCK-2 to recruit monocytes to the site of infection. Strikingly, MCMV deficient in MCK-2 was ineffective at delaying tumor growth. Further studies demonstrated that MCK-2 was necessary for MCMV to induce macrophage accumulation in the tumor and infiltration into the center of lesions. Finally, we found that repeated IT injections of MCMV caused more marked tumor growth delay and resulted in increased tumor clearance. Together, our results show that MCMV promotes tumor growth delay by modulation of the TAM compartment through recruitment of new macrophages via viral MCK-2 and infection of TAMs to promote an M1-like state within the tumor.

Citation Format: Nicole A. Wilski, Christina Del Casale, Vitali Alexeev, Constantine Daskalakis, Timothy J. Purwin, Andrew E. Aplin, Christopher M. Snyder. Cytomegalovirus infection of melanoma delays tumor growth by recruiting and altering monocytic phagocytes in the 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 A74.
Abstract A76: Anti IL-1b as a cancer immunotherapy
Authors: Singh Reshma , Diwanji Rohan , Jayaraman Pushpa , Chiang Derek , Sabatos-Peyton Catherine , Dranoff Glenn
Published: June 2021

Inflammation in cancer can both suppress tumor growth and promote tumorigenesis. In the tumor microenvironment (TME), inflammation characterized by inflammatory cells and other mediators including cytokines affects tumor development and progression and can have an impact on response to therapy. The inflammatory cytokine IL-1b is upregulated in several conditions including rheumatoid arthritis, chronic obstructive pulmonary disease, inflammatory bowel disease, as well as in different cancers including breast, gastric, pancreatic, and lung cancers. IL-1b contributes to the generation and accumulation of myeloid-derived suppressor cells (MDSCs). In the tumor microenvironment, MDSCs consist of a mixture of immature macrophages, immature dendritic cells and neutrophils, which can suppress the function of antitumor T cells. In addition, IL-1b is produced via activation of the inflammasome, which has been shown to promote the infiltration of MDSCs and tumor-associated macrophages (TAMs) into the TME. Downstream of IL-1b production are other inflammatory cytokines such as IL-6, IL-8, and IL-17, which can also suppress the immune system. Recently published data show that blocking IL-1b in patients without cancer can lead to a decrease in fatal cancer and more specifically lung cancer incidences and fatalities (Ridker et al., 2017). While the study was not designed to study the anticancer effects of canakinumab (Ilaris), this finding has led to increased interest in understanding the role of IL-1b and IL-1b blockade in cancer development and progression. Emerging data aim to elucidate the role of IL-1b blockade on tumor growth and progression, as well as characterize changes to tumor-infiltrating lymphocyte (TIL) populations and their function after treatment with an anti-IL-1b antibody.

Reference: Ridker PM et al. Effect of interleukin-1b inhibition with canakinumab on incident lung cancer in patients with atherosclerosis: exploratory results from a randomized, double-blind, placebo-controlled trial. Lancet 2017;390:1833-42.

Citation Format: Reshma Singh, Rohan Diwanji, Pushpa Jayaraman, Derek Chiang, Catherine Sabatos-Peyton, Glenn Dranoff. Anti IL-1b as a cancer 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 A76.
Abstract B16: Enabling checkpoint inhibitors with oncolytic viruses to deliver complete responses: A matter of timing
Authors: Cervera-Carrascon Victor , Quixabeira Dafne , Munaro Eleonora , Santos Joao M. , Havunen Riikka , Siurala Mikko , Hemminki Akseli
Published: June 2021

Checkpoint inhibitors (CPI) started a new golden era of immunotherapy for cancer treatment. Since approval of the first product in 2011, a number of these antibodies are now available for different indications. Hundreds of trials are ongoing, which could predict many further approvals soon. Unfortunately, only a minority of patients currently benefit from CPI treatment. One of the biggest limitations appears to be poor immune infiltration of many tumors, known as immune desert or excluded tumors. Oncolytic viruses are an interesting tool to use together with CPI to increase the frequency and the quality of patients’ responses. Besides their inherent ability to raise the immune alarm towards the tumor, resulting in recruitment of lymphocytes and other cells, they can be armed with transgenes to potentiate these effects. In a data-driven approach, adenoviruses expressing Tumor Necrosis Factor Alpha and Interleukin 2 were identified as the optimal approach for recruiting and activating T cells in tumors. In this approach, the regimen of administration must be considered as it can affect the outcome of the treatment. We used an aggressive and immunosuppressive solid tumor model (B16.OVA melanoma) to study the interaction between the above-mentioned viruses and anti-PD-1 and anti-PD-L1. After optimizing treatment regimes, control of every tumor led to complete responses in 100% of the animals when the viral platform and anti-PD-1 (or anti-PD-L1) were used together. This was a significant improvement when compared to them used as monotherapies (p-value <0.01), but the optimal regimens of administration were different for anti-PD-1 and for anti-PD-L1. Full data, including tumor growth control, survival and extensive immunologic characterization, revealing the mechanism of action, will be presented. Checkpoint inhibitors and oncolytic adenovirus are an attractive approach for increasing the proportion of patients benefiting from CPI therapy. It is of critical relevance to understand how to best use them to maximize their therapeutic effect. Our study underlines the importance of scheduling of the agents with each other, and the differences between CPI targets.

Citation Format: Victor Cervera-Carrascon, Dafne Quixabeira, Eleonora Munaro, Joao M. Santos, Riikka Havunen, Mikko Siurala, Akseli Hemminki. Enabling checkpoint inhibitors with oncolytic viruses to deliver complete responses: A matter of timing [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 B16.
Abstract B38: Hypoxia mediates downregulation of mTOR via miR-100 in cervical cancer cells
Authors: Takamizawa Shigeatsu , Yamanaka Zenta , Nishi Hirotaka
Published: June 2021

Objectives: Hypoxia occurs during development of cervical cancer and is considered to correlate with its malignancy. We found that hypoxia induced miR-100 whose expression was low in cervical cancer. We sought to determine the target molecules during hypoxia in cervical cancer.

Methods and Results: We found that the expression of miR-100 was significantly higher under hypoxic condition (1% O2) by realtime RT-PCR. According to the results of in silico analysis, miR-100 targeted mechanistic target of rapamycin (mTOR). Hypoxia and overexpression of miR-100 respectively decreased the activity of luciferase-reporter containing the 3’-untranslated region (UTR) of mTOR with the predicted miR-100-binding site in cervical cancer cell lines, CA and HeLa. By Western blot analysis, hypoxia downregulated the endogenous mTOR protein expression. mTOR mRNA level was also downregulated by hypoxia using realtime RT-PCR.

Conclusions: Our results suggest that miR-100 and mTOR could be a therapeutic target for cervical cancer.

Citation Format: Shigeatsu Takamizawa, Zenta Yamanaka, Hirotaka Nishi. Hypoxia mediates downregulation of mTOR via miR-100 in cervical cancer cells [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 B38.
Abstract B74: Immunologic characteristics of circulating tumor cells in patients with head and neck squamous cell carcinoma
Authors: Tada Hiroe , Takahashi Hideyuki , Ishii Hiroki , Kuwabara-Yokobori Yuki , Ida Shota , Shino Masato , Chikamatsu Kazuaki
Published: June 2021

Circulating tumor cells (CTCs) are cells that have shed from the tumor tissue into the bloodstream, and detection and enumeration of CTCs have been recognized as a useful test for personalized cancer therapy. Moreover, characterization of CTCs including epithelial-mesenchymal transition, stemness, and immune evasion phenotype is essential for a deeper understanding of cancer biology. To assess the immunologic characteristics of CTCs, we investigated the expression profile of immune-regulatory molecules, PD-L1, PD-L2, and CD47 in CTCs derived from patients with head and neck squamous cell carcinoma (HNSCC). Furthermore, the PD-L1 expression in the CTCs was compared with that in the tumor tissues assessed by immunohistochemistry. CTCs were isolated from 26 HNSCC patients with recurrent and/or distant metastasis by depletion of CD45-positive cells, and the expression of four epithelial markers (EpCAM, CK-19, EGFR, and c-Met) was first analyzed by qRT-PCR with a low concentration of RNA from the CTC population. Twenty (76.9%) of 26 patients tested were positive for at least one epithelial-related gene, indicating the existence of CTCs in those patients. Among 20 CTC-positive patients, 16 (80%), 13 (65%), and 15 (75%) patients were positive for CD47, PD-L1, and PD-L2, respectively. Of note, the mRNA expression level of each immune-regulatory molecule correlated positively with each other (PD-L1 vs PD-L2, p = 0.0028; PD-L1 vs CD47, p = 0.0015; PD-L2 vs CD47, p < 0.0001). Although the PD-L1 expression in the tumor tissues was positive in 12 (60%) of the 20 patients, concordance of the PD-L1 expression between the tumor tissues and the CTCs was observed in only 11 (55%) patients. Our findings suggest that, in some patients, CTCs may facilitate their evasion of innate and acquired antitumor immunity mediated via effector T cells, NK cells, and macrophages by expressing multiple immune-regulatory molecules. Currently, precise evaluation of PD-L1 expression are indispensable for the development of more effective and personalized therapeutic approaches using immune checkpoint inhibitors; therefore, the evaluation of PD-L1 expression in CTCs may enable real-time assessment as well as continuous monitoring of the PD-L1 status in tumor cells within tumor microenvironment.

Citation Format: Hiroe Tada, Hideyuki Takahashi, Hiroki Ishii, Yuki Kuwabara-Yokobori, Shota Ida, Masato Shino, Kazuaki Chikamatsu. Immunologic characteristics of circulating tumor cells in patients with head and neck squamous cell carcinoma [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 B74.
Abstract B76: Mature dendritic cells correlate with favorable immune infiltrate and improved prognosis in ovarian carcinoma patients
Authors: Truxova Iva , Kasikova Lenka , Hensler Michal , Skapa Petr , Laco Jan , Pecen Ladislav , Belicova Lucie , Praznovec Ivan , Halaska Michael J. , Brtnicky Tomas , Salkova Eva , Rob Lukas , Kodet Roman , Goc Jeremy , Sautes-Fridman Catherine , Fridman Wolf Herman , Ryska Ales , Galluzzi Lorenzo , Spisek Radek , Fucikova Jitka
Published: June 2021

A high density of tumor-infiltrating CD8+ T cells and CD20+ B cells correlates with prolonged survival in patients with a wide variety of human cancers, including high-grade serous ovarian carcinoma (HGSC). However, the potential impact of mature dendritic cells (DCs) in shaping the immune contexture of HGSC, their role in the establishment of T cell-dependent antitumor immunity, and their potential prognostic value for HGSC patients remain unclear. We harnessed immunohistochemical tests and biomolecular analyses to demonstrate that a high density of tumor-infiltrating DC-LAMP+ DCs is robustly associated with an immune contexture characterized by TH1 polarization and cytotoxic activity. We showed that both mature DCs and CD20+ B cells play a critical role in the generation of a clinically favorable cytotoxic immune response in HGSC microenvironment. In line with this notion, robust tumor infiltration by both DC-LAMP+ DCs and CD20+ B cells was associated with most favorable overall survival in two independent cohorts of chemotherapy-naive HGSC patients. Our findings suggest that the presence of mature, DC-LAMP+ DCs in the tumor microenvironment may represent a novel, powerful prognostic biomarker for HGSC patients that reflects the activation of clinically relevant anticancer immunity.

Citation Format: Iva Truxova, Lenka Kasikova, Michal Hensler, Petr Skapa, Jan Laco, Ladislav Pecen, Lucie Belicova, Ivan Praznovec, Michael J. Halaska, Tomas Brtnicky, Eva Salkova, Lukas Rob, Roman Kodet, Jeremy Goc, Catherine Sautes-Fridman, Wolf Herman Fridman, Ales Ryska, Lorenzo Galluzzi, Radek Spisek, Jitka Fucikova. Mature dendritic cells correlate with favorable immune infiltrate and improved prognosis in ovarian carcinoma patients [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 B76.
Abstract B91: Plasmacytoid dendritic cells in HPV+ and HPV- head and neck cancer
Authors: Koucký Vladimír , Hladíková Kamila , Bouček Jan , Fialová Anna
Published: June 2021

Introduction: Plasmacytoid dendritic cells (pDC) are the most important IFN type I producing cells. They play an essential role in viral infections; however, they are studied in context of many pathologic conditions including malignancies. Data show their negative effect on patient prognosis in breast, ovarian, skin and oral cancer, but also a possible antitumoral effect is discussed. In case of head and neck cancer (HNSCC), it is assumed that tumor-infiltrating pDC (TIpDC) are dysfunctional and support immunosuppressive environment. Hence, there are no data on the functional state of pDC in relation to HPV status of tumors, despite the fact that a dominant part of oropharyngeal cancer is viral-driven, having better prognosis.

Methods: Phenotype and functional state of pDC in tumor-derived single-cell suspensions, tonsils and PBMC was analyzed by flow cytometry. Plasmacytoid DC were identified as CD45+, Lineage -, CD4+, BDCA2+, CD123+ cells. Expression of stimulatory and regulatory molecules (TLR7, TLR 9, NKp44, TIM3, IDO, Granzyme B) was assessed. Cytokine levels in cell culture supernatants were detected using Luminex (IFNα, IFNγ, IL-10, IL-12, IL-17, IL-3, IL-4, IL-6, TNFα, TNFβ). For stimulatory tests CpG A 2216 and Imiquimod were used.

Results: We found higher proportions of circulating pDC in HPV+ patients (p=0.045). However, there was no difference in numbers of TIpDC in HPV+ and HPV- HNSSC. We also observed the same number of TIpDC able to react to TLR 7 and TLR 9 stimulation. Nevertheless, pDC from HPV+ tumors showed a potential to produce significantly higher levels of IFNα upon CpG A stimulation (p=0.013). In relation to this, surprisingly, NKp44 expression, referred as negative regulator of IFNα secretion in tonsils, was higher in HPV+ patients (p=0.049). There was no correlation with other regulatory molecules expressed on pDC nor the number of tumor-infiltrating Tregs.

Conclusion: Plasmacytoid DC might play an important role in regulation of tumor microenvironment in patients with HNSCC. Our data show functional differences between pDC infiltrating HPV+ and HPV- cancer, suggesting that these cells contribute to the different biology and prognosis of HPV-induced cancer.

Citation Format: Vladimír Koucký, Kamila Hladíková, Jan Bouček, Anna Fialová. Plasmacytoid dendritic cells in HPV+ and HPV- head and neck 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 B91.
Abstract B93: Investigating the role of the hematopoietic-specific DNMT3A mutations in the aggressive phenotype of colon cancer
Authors: Feng Yang , Shabashvili Daniil E. , Posada Luisa M. , Krajcik Kathryn I. , Gunaratne Chamara , Guryanova Olga A.
Published: June 2021

Clonal hematopoiesis (CH) is a nonmalignant condition characterized by clonal expansion of one or few hematopoietic stem cells. CH is associated with advanced age and presence of presumed leukemic driver mutations, such as in the DNMT3A gene. Clinical studies show that presence of CH mutations in the bone marrow in patients with solid tumors is associated with unfavorable prognosis and shorter survival. Moreover, CH mutations are enriched in tumor-infiltrating leukocytes compared to peripheral blood. While these observations have profound clinical implications, the understanding of the relationship between mutations in the blood system and aggressive phenotype of solid tumors is still lacking. We hypothesized that bone marrow-derived cells harboring alterations in DNMT3A contribute to tumor-promoting microenvironment through immune imbalance. To this end, we established a mouse model of CH driven by Dnmt3a alterations and are investigating its effect on a well-established colitis-associated colon cancer model (CAC) as a prototypical solid tumor. Wild-type recipient mice were transplanted with bone marrow from animals with: a) heterozygous loss of Dnmt3a (Dnmt3a+/−); b) Dnmt3a R878H point-mutation (Dnmt3aRH); c) wild-type controls (Dnmt3a+/+). Since inflammation is known to promote tumorigenesis, we are testing the sensitivity of engrafted mice to experimental colitis induced by 2.5% dextran sulfate sodium salt (DSS) in drinking water. Animals of all 3 experimental groups will be co-housed to control for cage-to-cage variability in microbiota. We will use total body weight loss, histopathology of harvested colons (swiss roll method)/colitis scores, colon size, and appearance of intestinal contents as a readout for colitis severity. Next, we will investigate AOM/DSS-induced tumorigenesis in CH model, including tumor burden and extent of inflammation between experimental groups. Finally, we will characterize tumor-infiltrating leukocytes that contribute to aggressive CAC phenotype to identify immune populations that engender this tumor-modulating function, including epigenetic and gene expression profiles. Our goal is to understand the relationship between mutations in the blood system and aggressive phenotype of nonhematologic cancers and to nominate potential targets for therapeutic intervention.

Citation Format: Yang Feng, Daniil E. Shabashvili, Luisa M. Posada, Kathryn I. Krajcik, Chamara Gunaratne, Olga A. Guryanova. Investigating the role of the hematopoietic-specific DNMT3A mutations in the aggressive phenotype of colon 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 B93.
Abstract B94: Targeted ablation of FoxP3+ T cells activates peripheral and tumor-infiltrating cytotoxic CD8+ T cells in multiple syngeneic mouse tumor models
Authors: Wang Yingyun , Delfino Teresita , Schartner Jill M. , Rutz Sascha
Published: June 2021

FoxP3+ regulatory T cells (Treg) are essential to prevent autoimmunity but have also been implicated in suppressing antitumor immune responses. We assessed the impact of depletion of Treg cells in 8 different syngeneic tumor models, including cancer immunotherapy-sensitive and -resistant models. Robust, rapid tumor control or regression was observed in all models tested. Analysis of both peripheral and tumor-infiltrating T cells revealed that Treg cell depletion resulted in robust proliferation and cytokine production by CD8+ T cells in lymph nodes, spleen and tumor tissue. Tumor regression was CD8+ T cell-dependent, as antibody-mediated depletion of these cells abrogated tumor regression in a representative model. Interestingly, studies using FTY720 to pharmacologically block T-cell egress from the lymph nodes suggest that following Treg depletion cancer immunotherapy-sensitive models may not require new T-cell infiltration into tumor for tumor regression. This is in contrast to an immunotherapy-resistant model, which failed to regress following Treg depletion when lymph node egress was concurrently blocked. These data suggest that Treg cells play a critical role in suppressing both priming of novel anti-tumor CD8+ T-cell responses as well as limiting effector functionality of tumor-infiltrating CD8+ T cells within the tumor microenvironment.

Citation Format: Yingyun Wang, Teresita Delfino, Jill M. Schartner, Sascha Rutz. Targeted ablation of FoxP3+ T cells activates peripheral and tumor-infiltrating cytotoxic CD8+ T cells in multiple syngeneic mouse tumor models [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 B94.
Abstract IA13: LC3-associated phagocytosis in inflammation and anticancer immunity
Authors: Green Douglas R.
Published: June 2021

Two ancient processes, phagocytosis and macroautophagy, arose as mechanisms of meeting the energy demands of the cell. Both also evolved into mechanisms of host defense. We have described a process we term “LC3-associated phagocytosis” (LAP), in which signals that are generated upon engulfment of particles by phagocytic cells induce components of the autophagy machinery to associate with the phagosome, promoting its fusion to lysosomes (phagosome maturation). While engulfment of latex beads (for example) does not induce LAP, particles that engage TLR1/2, TLR2/6, TLR4, FcR, or receptors for engulfment of dying cells, cause recruitment of LC3 (ATG8) to the phagosome membrane. Like macroautophagy, this LC3 association depends on Beclin1, PI3P generation, ATG5, and ATG7, but unlike autophagy, LC3 associates with the single phagosome membrane (rather than the double membrane of autophagosomes). Further, unlike macroautophagy, LAP proceeds in the absence of elements of the autophagic preinitiation complex, ULK1, ATG13, and FIP200, and involves a novel PI3K complex. This raises an intriguing possibility: It is now well established that defects in some components of the autophagy machinery promote inflammatory disease and compromise host defense to intracellular infections. While such effects are generally interpreted as consequences of defective macroautophagy, the existence of LAP as a discrete phenomenon suggests that at least some such effects may specifically relate to LAP. I will discuss LAP and its relationship to phagosome maturation, and its roles in anticancer immunity and inflammatory disease.

Citation Format: Douglas R. Green. LC3-associated phagocytosis in inflammation and anticancer immunity [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 IA13.
Abstract IA16: Imaging a world beyond checkpoints: Classes of immune responses in cancer
Authors: Krummel Matthew F.
Published: June 2021

Checkpoint blockades have opened up the door for treatment of cancer by using modulation of immune programming. However, the fact that not everyone responds equivalently has long pointed to the existence of different immune pathologies in different individuals. Using real-time imaging as an initial method of discovery, we have explored the immunopathologies associated with over a dozen types of cancer and describe patterns or classes of responsiveness. We also describe emerging and opposing classes of immune systems that resist checkpoint blockade and for which truly orthogonal treatments will be required.

Citation Format: Matthew F. Krummel. Imaging a world beyond checkpoints: Classes of immune responses 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 IA16.
Abstract PR16: RNA aptamers specific for tumor-infiltrating myeloid cells
Authors: De La Fuente Adriana , Caroli Jimmy , Van Simaeys Dimitri , Zilio Serena , Mazza Emilia , Bronte Vincenzo , Bicciato Silvio , Serafini Paolo
Published: June 2021

Myeloid cells have been extensively studied in the tumor microenvironment for their role in promoting cancer cell survival and metastases. However, their peculiar activated phenotype has not been exploited for the targeted delivery of anticancer agents to the tumor site. Here we report a new therapeutic strategy that allows the delivery of cancer drugs to both tumor and metastases by the preferential targeting of genetically stable tumor-infiltrating myeloid cells (TIMC). We identified 4 monoclonal RNA aptamers that specifically recognize myeloid-derived suppressor cells (MDSC) and macrophages infiltrating the tumor, but not the splenic counterparts. The use of these aptamers conjugated to doxorubicin greatly enhances the accumulation of the chemotherapeutic drug in the primary and metastatic tumor sites in multiple cancer models. Compared to their individual components or current therapeutic approaches, doxorubicin-conjugated TIMC-specific aptamers show enhanced anticancer efficacy and no detectable treatment-related toxicity. This strategy has the intrinsic potential to target multiple tumor types through the same reagents.

This abstract is also being presented as Poster A35.

Citation Format: Adriana De La Fuente, Jimmy Caroli, Dimitri Van Simaeys, Serena Zilio, Emilia Mazza, Vincenzo Bronte, Silvio Bicciato, Paolo Serafini. RNA aptamers specific for tumor-infiltrating myeloid cells [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 PR16.
Association of p16 and Ki-67 with Risk of Recurrence in Previously Treated Cervical High-Grade Squamous Intraepithelial Lesions
Authors: Arredondo-Gálvez Carlos Germán , Acuña-González Denise , Cantú-de-León David , Chanona-Vilchis José Gregorio , Avilés-Salas Alejandro , González-Enciso Aarón , Bandala-Jaques Antonio , Barquet-Muñoz Salim Abraham
Published: June 2021

Objective: Our main objective was to assess the association between the markers p16 and Ki-67 and recurrence of disease in patients previously treated for cervical high-grade squamous intraepithelial lesion (HSIL). Design: This is a case-control study at the National Cancer Institute conducted between 2005 and 2015. Of the patients with a pathologically confirmed diagnosis of HSIL, 107 cases were selected. They were divided into 2 groups: 28 cases with recurrence after treatment and a control group of 79 patients without recurrence. We identified clinical, pathological, and treatment variables. Methods: Two experienced pathologists performed immunohistochemical analysis of biomarkers; they agreed on their interpretation, and we calculated the odds ratios (ORs) associated with recurrence. For group comparisons, we used the Wilcoxon signed-rank, χ2, or Fisher’s exact test, depending on the type of variable. We conducted logistic regression models to estimate ORs and determine the factors associated with recurrence. The recurrence-free period was defined as the time frame between conization and either recurrence of disease or the last date the patient was seen. We used Kaplan-Meier plots to visualize survival curves and log-rank tests to compare the curves. We established a p value <0.05 as statistically significant. Results: After pathologists performed immunohistochemical analysis, they achieved an agreement level of 83.7% for p16 and 60% for Ki-67. We did not find an association between recurrence and either p16 expression (p = 0.69) or the percentage of Ki-67 expression (p = 0.71). The recurrence-free period analysis did not reveal a difference in p16 expression (p = 0.57) nor in the percentage of Ki-67 expression in the 3-tiered scale (p = 0.56). Limitations: Our main limitation was a reduced sample size. Conclusion: We found no association between p16 and Ki-67 positivity and the risk of recurrence in previously treated HSIL.
Strip planted mechanical seeding of mustard and mungbean with crop residue retention is more profitable than conventional practice
Authors: Hossain M. M. , Begum M. , Rahman M. M.
Published: June 2021

Smallholder agriculture of the Asian continent faces a significant challenge of declining soil productivity and an acute shortage of ag-ricultural labor. Reduced tillage and crop residue mulch application is an integrated approach to preserving soil health and addressing the labor crisis to maintain farm sustainability. We undertook this study to evaluate the effect of strip planting and increased residue mulching on mustard and mungbean's productivity and profitability in northern Bangladesh during 2015 and 2016. Mustard cv. BARI Sharisha 14 and mungbean cv. BARI Mungbean 6 was grown follow-ing (i) Conventionally Tilled broadcasting method (CT) and (ii) Strip Planted line seeding (SP) with two levels of crop mulch (i) no-mulch and (ii) 50% mulch. The CT was done by a two-wheel tractor with four plowings and cross plowing followed by leveling. In SP, single tillage, seeding, fertigation, and field leveling were done simultane-ously by a Versatile Multi-crop Planter machine. Results reveal that mechanized seeding of mustard and mungbean in SP with 50% resi-due mulching fetched 62% higher profit than broadcasted CT with-out residue through producing 24% higher seed yield. This practice reduced the land preparation costs by 68%, in association with re-ducing the labor and fuel requirements by 30%. Hence, it could be concluded that the mechanized seeding of mustard and mungbean with the retention of 50% of crop residue is profitable to the con-ventionally broadcasted seeding process.
Evaluation of stored potato (Solanum tuberosum L.) for soft rot bacteria in Ibadan, Nigeria
Authors: Abiodun Durojaye Hammed , Abisola Owoeye Tolulope
Published: June 2021

Potato (Solanum tuberosum L.) is a tuberous crop from the Sola-naceae family which is a source of starch and food to many in Nige-ria, however, its production is being hampered in field and storage by bacterial pathogen which causes rot of the stored tubers. To this end, the study aimed at screening potatoes from different stores within Ibadan for the evaluation and diversity of bacteria pathogens responsible for rot in potatoes. Damaged stored potato samples were collected from different locations in Ibadan for studies, these samples were isolated for bacterial pathogen and characterized bio-chemically and observed under the microscope for identification. Three genera of bacteria were observed to be responsible for potato rot in the study and they include Pectobacterium carotovorum, Pseu-domonas syringae and Ralstonia solanacearum. Of all the isolated bacteria, Pectobacterium carotovorum has the highest occurrence with a frequency of 60%, while Pseudomonas syringae has a fre-quency of 33% and Ralstonia solanacearum has a frequency of 27%. The pathogenicity of the isolates were tested and this revealed that Pectobacterium carotovorum is the most virulent with a severity score of 4.3, while Ralstonia solanacearum follows with a score of 3.3 and a score of 2.7 was recorded for Pseudomonas syringae, while the control had a score of 0. The diversity and differences shown in the isolated bacteria indicated that potato rot is a serious disease which is caused by different bacteria and need an integrated ap-proach for its control from the field of harvesting to the storage house.