bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A211: Requirement of Treg-intrinsic CTLA4-PKCeta signaling pathway for suppressing tumor immunity
Authors: Pedros Christophe , Liu Hsin-Yu , Canonigo-Balancio Ann J. , Kong Kok-Fai , Altman Amnon
Published: February 2019

The ability of Tregs to control the development of immune responses is essential for maintaining immune system homeostasis. However, Tregs also inhibit the development of efficient antitumor immune responses. Here we explored the characteristics and mechanistic basis of the Treg-intrinsic CTLA4-PKCη signaling pathway that we recently found to be required for contact-dependent Treg-mediated suppression. We show that PKCη is required for the Treg-mediated suppression of tumor immunity in vivo. The presence of PKCη-deficient (Prkch-/-) Tregs in the tumor microenvironment was associated with a significantly increased expression of the costimulatory molecule CD86 on intratumoral CD103+ DCs, enhanced priming of antigen-specific CD8+ T-cells, and greater levels of effector cytokines produced by these cells. Tumor development was reduced similarly in Treg-specific (Prkch-flox x Foxp3-Cre) and globally deficient recipients (Prkch-/-) as compared to wt mice, indicating that PKCη expression by effector cells is dispensable for the development of efficient anti-tumor responses. Similar to mouse Tregs, the GIT-PAK-PIX complex also operated downstream of CTLA4 and PKCη in human Tregs, and GIT2 knockdown in Tregs promoted antitumor immunity. We are now exploring the therapeutic impact of PKCη deletion in tumor-bearing mice using tamoxifen treatment of Prkch-flox x Foxp3-ERT2Cre and Prkch-flox x UBC-ERT2Cre mice as a surrogate for treatment with a highly selective and efficient PKCη inhibitor. Collectively, our data suggest that targeting the CTLA4-PKCη-GIT-PAK-PIX signaling pathway in Tregs could represent a novel immunotherapeutic strategy to alleviate the negative impact of Tregs on antitumor immune responses.

Citation Format: Christophe Pedros, Hsin-Yu Liu, Ann J. Canonigo-Balancio, Kok-Fai Kong, Amnon Altman. Requirement of Treg-intrinsic CTLA4-PKCeta signaling pathway for suppressing tumor immunity [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A211.
Abstract A226: Cell-free membrane reconstitution system for cis and trans interaction of T-cell co-receptors and ligands
Authors: Zhao Yunlong , Hui Enfu
Published: February 2019

Immunotherapy, which harnesses the immune system to combat cancers, is a paradigm-shifting approach in oncology. One important branch of immunotherapy is to use drugs to perturb molecular interactions at the T-cell–antigen presenting cell (APC) interface. In particular, antibodies that block the T-cell coinhibitory receptor PD-1 or its ligand PD-L1 have produced unprecedented clinical activities against a subset of human cancers in a fraction of patients. Extending immunotherapy to a larger patient population requires a better understanding of the interaction network at the T-cell-APC interface. Typically, it is believed that ligands from APCs bind to receptors on T-cells (in trans) to trigger intracellular signaling. A largely overlooked fact is that many receptors often co-exist with ligands on T-cells and APCs, including PD-1/PD-L1 and CD28/B7.1. Using novel reconstitution approaches, we recently discovered that co-expressed PD- 1 and PD-L1 bind to each other in cis and this cis interaction competes with their trans interaction to inhibit PD-1 signaling. We hypothesize that cis interaction occurs with many other ligand-receptor pairs and may regulate other aspects of tumor immunity by perturbing their trans interactions. We are currently using our robust reconstitution systems to ask whether other immunoreceptors and ligands interact in cis and how the putative cis interaction affect their trans interactions. Specifically, to detect cis interaction, we co-attach the ligand and receptor to liposomes, and probe their cis interaction using a fluorescence resonance energy transfer (FRET) readout. To detect trans interaction, we have developed a liposome-lipid bilayer conjugation assay, in which binding between ligand- labeled liposomes and receptor-labeled supported lipid bilayer (SLB) is used as an index for trans interaction. To determine whether cis interaction inhibits trans interaction, we ask in the liposome-bilayer system if addition of receptor on liposomes decreases liposome-SLB conjugation. Our preliminary data revealed that CD28 only binds B7.1 in trans, but not in cis. In contrast, PD-1 binds with PD-L1 both in cis and trans, and the two modes of interaction compete with each other. Further experiments in cells confirmed our finding in vitro, demonstrating the utility of our cell-free reconstitution systems in detecting cis and trans interaction of T-cell co-receptors. Insights from this study will help us clarify the ligand-receptor interaction network at the immunological synapse.

Citation Format: Yunlong Zhao, Enfu Hui. Cell-free membrane reconstitution system for cis and trans interaction of T-cell co-receptors and ligands [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A226.
Abstract B012: Characterizing tumor-induced exhaustion in melanoma patients treated with neoadjuvant pembrolizumab
Authors: Giles Josephine R. , Huang Alexander C. , Manne Saskinath , Henao-Meji Jorge , Wherry E. John
Published: February 2019

Immune checkpoint blockade, including anti-PD-1 therapies, has had unprecedented success in treating various forms of cancer, including melanoma. Yet the majority of patients do not achieve durable clinical remission. The limited understanding of how these therapies work at the cellular and molecular level prevents the optimization required to improve patient outcomes. We performed RNA-seq and ATAC-seq on four sorted T-cell subpopulations (naïve CD8 T-cells, non-naïve CD8, non-naïve CD4 T-cells, T regulatory cells) from patients with metastatic melanoma before and after pembrolizumab treatment. While there were no significant changes before and after treatment in the sorted peripheral blood populations, we identified many alterations in the tumor compared to the blood following treatment. These differences may represent impediments to fully reinvigorating exhausted T-cells and be potential targets for achieving more durable clinical responses. We identified a zinc finger gene, ZC3H12C, as not only one of the most highly upregulated in non-naïve CD8 T-cells in the tumor, but it also had the highest number of associated altered open chromatin regions. This gene and its locus are also significantly different in exhausted T-cells compared to effector and memory cells in a mouse model of chronic viral infection using Lymphocytic choriomeningitis (LCMV). This conservation between species suggest an important role in T-cell exhaustion and provided an avenue to test its function in vivo, so we generated ZC3H12C knockout mice using CRISPR-Cas9. Following C13 (chronic) LCMV infection, virus-specific P14 CD8 T-cells lacking ZC3H12C are unable to persist compared to wild type P14 cells. These results suggest ZC3H12C may be critical to the survival of exhausted T-cells in the tumor and their ability to persist after anti-PD1 treatment. Here, we used transcriptomic and epigenetic analysis of a clinical human cancer data set to identify a novel target and used reverse translation in a mouse model to validate its importance in T-cell exhaustion. This gene and more broadly this strategy have the potential to provide immediately useful targets for improving immunotherapies.

Citation Format: Josephine R. Giles, Alexander C. Huang, Saskinath Manne, Jorge Henao-Meji, E. John Wherry. Characterizing tumor-induced exhaustion in melanoma patients treated with neoadjuvant pembrolizumab [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B012.
Abstract B036: T-cell recognition of breast cancer antigens
Authors: Petersen Nadia Viborg , Ramskov Sofie , Andersen Rikke Sick , Met Özcan , Straten Per thor , Bentzen Amalie Kai Kai , Hadrup Sine Reker
Published: February 2019

Breast cancer remains the leading cause of cancer death among women worldwide, rendering conventional therapies insufficient despite decades of research. Despite originally considered an immunologically silent malignancy, recent studies have shown encouraging results, from treatment of breast cancer with checkpoint inhibition to enhance the immunogenicity and tumor cell killing mediated by immune cells. The epitope landscape in breast cancer is minimally described; thus it is necessary to identify T-cell targets to develop cancer-specific immune-mediated therapies. This project investigates four proteins commonly upregulated in breast cancer and thus probable tumor-associated antigens (TAAs), namely, aromatase, prolactin, never in mitosis a related kinase 3 (NEK3), and protein inhibitor of activated STAT3 (PIAS3). Each contributes to increase growth, survival, and motility of malignant cells. To uncover novel epitopes for cytotoxic T-cells, a reverse immunology approach is applied. In silico screening via NetMHC was used to predict peptides within the full length of each of the four proteins that bind to HLA-A*0201 and HLA-B*0702. Via in silico screening 415 HLA-A*0201 or HLA-B*0702 binding peptides were predicted An MHC ELISA was applied to experimentally confirm which of the peptides are true HLA-A*0201 and HLA-B*0702 binders, reducing the library from 415 to 147. The 147 peptides were evaluated for T-cell recognition utilizing DNA barcode labeled MHC multimers to screen peripheral blood lymphocytes from 24 breast cancer patients and 18 healthy donor samples. Significantly more TAA specific T-cell responses were detected in breast cancer patients than healthy donors for both HLA-A*0201 (p=0.0039) and HLA-B*0702 (p<0.001) restricted peptides. Thus, the inspected proteins aromatase, prolactin, NEK3 and PIAS3 indeed contain targets for T-cell reactivity. Importantly, several of the responses were identified towards peptides with a predicted intermediate HLA-binding affinity. This emphasizes the importance of including such weaker affinity ligands in the search for epitopes within shared TAAs.

Citation Format: Nadia Viborg Petersen, Sofie Ramskov, Rikke Sick Andersen, Özcan Met, Per thor Straten, Amalie Kai Kai Bentzen, Sine Reker Hadrup. T-cell recognition of breast cancer antigens [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B036.
Abstract B041: An injectable magnetic nanogel system for filling surgical residual cavity with effective cancer immunotherapy combined hyperthermic capability
Authors: Sasikala Arathyram Ramachandra Kururp , Unnithan Afeesh Rajan , Park Chan Hee , Kim Cheol Sang
Published: February 2019

The advancement in nanotechnology has created a wealth of new possibilities for treating cancer with multifunctional nanosystem holding various therapeutic strategies in a single platform. It has been reported that magnetic nanoparticle hyperthermia can induce antitumor immunity whereas the immunotherapy can naturally trigger the immune system with the help of an appropriate stimulator to control cancer. Therefore the present study investigates the effectiveness of a hybrid nanocomposite system to effectively exterminating the tumor associated immune cells (TICs) as well as inducing an inflammatory immune response by activating killer T-cells by combining magnetic hyperthermia with an immunostimulatory agent. Here we report an injectable magnetic nanogels conjugating a checkpoint inhibitor (T-lymphocyte antigen-4 [CTLA4]) and a Toll-like receptor (TLR) agonists (imiquimod) for generating an effective antitumoral immune response for postsurgical glioma treatment. The injectable conductive magnetic hydrogel system enables the tracing and deterring of the recurrent tumor cells via magnetic nanoparticle-mediated hyperthermia with the strong immunologic memory effect. The superparamagnetic iron oxide nanoparticles encapsulated nanogels exhibit an induced heating ability in an alternating magnetic field (AMF) and thereby trigger the tumor cells to undergo a burst release of heat shock proteins to recruit immune cells to generate tumor-allied antigens. These antigens along with the released imiquimod from the hydrogel can generate vaccine-like functionalities. Moreover, the introduction of anti-cytotoxic T-lymphocyte antigen-4 (CTLA4) as a checkpoint-blockade will generate memory T-cells, which in turn will attack the metastatic and recurrent tumor cells. Above all, the conductive bioactive scaffold will support the neuronal regeneration and reactivation of brain cells. Thus our multifunctional novel hydrogel system will be able to fill the surgical residual cavity to prevent the glioma recurrence and will improve the local neuronal tissue reconstruction along with hyperthermic-immunotherapy.

Citation Format: Arathyram Ramachandra Kururp Sasikala, Afeesh Rajan Unnithan, Chan Hee Park, Cheol Sang Kim. An injectable magnetic nanogel system for filling surgical residual cavity with effective cancer immunotherapy combined hyperthermic capability [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B041.
Abstract B053: In vivo metabolic labeling and targeted modulation of dendritic cells for enhanced cancer immunotherapy
Authors: Wang Hua , Mooney David J.
Published: February 2019

Targeted immunomodulation of dendritic cells (DCs) is critical for optimizing antigen presentation processes and amplifying anticancer immune responses, but a general strategy has been lacking thus far. Here we show that the subcutaneously injected pore-forming alginate gels loaded with GM-CSF and azido-sugar nanoparticles can recruit and metabolically label DCs with azido groups in vivo, which allows for tracking and targeted modulation of DCs that migrate out of the gel scaffolds. Azido-labeled DCs were detected in both the gels and draining lymph nodes and enabled targeted delivery of dibenzocyclooctyne (DBCO)-bearing antigens and adjuvants via efficient Click chemistry, resulting in a higher level of antigen-specific CD8+ T-cells and better antitumor efficacy in comparison to unmodified antigens and adjuvants. We further show that azido-labeled DCs enable surface display of DBCO-cytokines, IL2 and IL15/IL15R for example, for targeted modulation of effector T-cells, which provides a general strategy to manipulate DCs and DC-T-cell interaction in vivo and opens a new avenue for developing enhanced cancer immunotherapy.

Citation Format: Hua Wang, David J. Mooney. In vivo metabolic labeling and targeted modulation of dendritic cells for enhanced cancer immunotherapy [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B053.
Abstract B073: A pan-HLA predictor of neoantigen processing and presentation to the tumor cell surface
Authors: Clancy Trevor , Stratford Richard
Published: February 2019

Currently, neoantigens are often predicted using algorithms predominantly based on knowledge of the key peptide binding affinity difference between HLA alleles. Although HLA binding algorithms predict binding affinity of a peptide to HLA reasonably well, they do not predict processing and presentation of to the cell surface (i.e., the immunopeptidome). In fact, only 15%–20% of “predicted” peptide binders are processed or presented, and therefore contribute to the immunopeptidome. Erroneous predictions may be addressed with time-consuming and laborious experiments, such as mass-spectrometry (MS). However, in silico predictions may also prove to be very useful in prioritizing therapeutically relevant immunogenic peptides. Previous in silico studies that predict naturally processed and presented peptides to the cell surface have focused on only one of the many steps in the antigen processing and presentation pathway (such as TAP transport or proteasome cleavage, etc.). Additionally, previous antigen processing prediction tools have been trained and are therefore applicable to specific HLA alleles, making it challenging to make predictions for not so well-characterized alleles. Here, we outline a machine learning approach trained on MS elution data that predicts, in a pan-HLA manner, natural processing and presentation of neoantigens to the cell surface. The predictor is integrated with multiple immune parameters in a deep learning layer to predict neoantigens, and may be used for more accurate neoantigen predictions for any HLA allele, in both the class I and class II systems. Further, by analyzing previously published clinical data we illustrate that its application leads to a significantly improved identification of neoantigen targets for personalized cancer immunotherapy.

Citation Format: Trevor Clancy, Richard Stratford. A pan-HLA predictor of neoantigen processing and presentation to the tumor cell surface [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B073.
Abstract B084: Methylation landscape of tumors associated with antitumor immune signature
Authors: Ock Chan-Young , Park Changhee , Jeong Kyeonghun , Jung Sohee , Bae Jeong Mo , Kim Kwangsoo
Published: February 2019

The most reliable predictive biomarker of cancer immunotherapy is gene expression profile (GEP) of tumor microenvironment. GEPs such as local immune cytolytic activity, interferon-gamma signature, and immune signature score have been reported to represent anti-tumor immune signature. Previously, we reported that immune signature score was positively correlated with tumor mutational burden, but negatively correlated with chromosomal instability (CIN) score, since tumors with high CIN score had significantly low neoantigen burden. However, methylation signature or burden of tumor would also affect antitumor immunogenicity, there has been no analysis reported so far. In the current study, we investigated if methylation landscape of tumor would be associated with GEPs of anti-tumor immune signature using The Cancer Genome Atlas (TCGA) pan-cancer database. In TCGA, 8269 pan-cancer samples had both RNA sequencing data and methylation data using Infinium HumanMethylation450K BeadChip, which were included in the main analysis. Although tumors with high mutational burden (Mu-type) and high CIN burden (C-type) were exclusively classified with negative correlation, methylation burden was not correlated with mutational burden or CIN burden in any pattern. Interestingly, antitumor immune signature measured by local immune cytolytic activity (CytAct) was clearly decreased with high methylational burden, as seen in high CIN burden. Hypermethylation of promoter of genes related to tumor antigen recognition by T-cell such as HLA family, B2M, CD74, and CD274 (PD-L1) were negatively associated with CytAct in pan-cancer analysis. In conclusion, methylation signature of tumor is also associated with antitumor immunogenicity with a negative correlation in general. Further study of whether specific methylation pattern would be associated with anti-PD-1/PD-L1 inhibitors in clinical study would be warranted.

Citation Format: Chan-Young Ock, Changhee Park, Kyeonghun Jeong, Sohee Jung, Jeong Mo Bae, Kwangsoo Kim. Methylation landscape of tumors associated with antitumor immune signature [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B084.
Abstract B099: Elucidating the mechanisms that underpin RAG chromatin scanning in V(D)J recombination at antigen receptor gene loci
Authors: Ba Zhaoqing , Jain Suvi , Hu Jiazhi , Alt Frederick
Published: February 2019

Immunoglobulin heavy (IgH) and light (IgL) chain variable region exons are assembled from V, D and J segments by V(D)J recombination, which is initiated by RAG1/RAG2 endonuclease (RAG) that introduces DNA double-stranded breaks (DSBs) between a pair of V, D, and J coding segments and flanking recombination signal sequences (RSSs). IgH V(D)J recombination is ordered, with D-JH joining occurring before appendage of a VH to a DJH intermediate in pro-B cells. In pre-B cells, a single-step VL-to-JL recombination event is invoked at IgL loci, with Ig kappa rearrangement usually preceding that of Ig lambda. The mechanisms of Ig V(D)J recombination, especially long-range VH-to-DJH and Vkappa-to-Jkappa recombination are still not fully understood. Recently, our work showed CTCF-binding elements (CBEs) immediately downstream of frequently rearranged VH-RSSs increase recombination potential of their associated VH far beyond that provided by RSS alone. This CBE activity becomes particularly striking upon the inactivation of IgH IGCR1 control element, which promotes DJH intermediate formation by insulting Ds, JHs, and recombination center (RC) from upstream VHs in a CBE-anchored chromatin loop. By developing and applying 3C-HTGTS, a new high-throughput chromosome conformation capture method that shows great advantages over classical 4C-seq in sensitivity and specificity, we found VH-associated CBEs promotes interaction with the RC. Based on these, we proposed a RAG chromatin scanning model for V(D)J recombination, in which VH CBEs stabilize interactions of D-proximal VHs first encountered by the DJH RC during linear RAG scanning on chromatin and thereby promote dominant rearrangement of these VHs by an unanticipated chromatin accessibility-enhancing CBE function. However, it is still not known if such chromatin scanning also happens on other antigen receptor loci and what the underlying mechanism is. Here, we will show our new findings on the roles of RAG chromatin scanning in Vkappa-to-Jkappa recombination at Ig kappa locus by multiple comprehensive approaches. Moreover, we will also discuss our most updated understanding of the mechanisms underlying RAG chromatin scanning using a novel and sophisticated approach. The potent mutagenic and oncogenic effects of aberrant RAG chromatin scanning at RAG “off-target” sites genome-wide will be also discussed.

Citation Format: Zhaoqing Ba, Suvi Jain, Jiazhi Hu, Frederick Alt. Elucidating the mechanisms that underpin RAG chromatin scanning in V(D)J recombination at antigen receptor gene loci [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B099.
Abstract B107: Next generation of poxvirus-based immunotherapeutics
Authors: Fend Laetitia
Published: February 2019

Oncolytic virus (OV) therapy has emerged as a promising approach for cancer treatment with the potential to be less toxic and more efficient than classic cancer therapies. Various types of OVs in clinical development, including Vaccinia virus (VACV)-derived OVs, have shown good safety profiles. We report here that a VACV can induce immunogenic cell death and generate a systemic immune response. Effects on tumor growth and survival was largely driven by CD8 T-cells, and immune cell infiltrate in the tumor could be reprogrammed toward a higher ratio of effector CD8 T-cells to regulatory CD4 T-cells. We demonstrate also the successful vectorization of a monoclonal anti-mPD-1 antibody in our VACV. The vectorized anti-mPD-1 antibody was able to block the binding of mPD-1 ligand to mPD-1 in vitro. Moreover, mAb was detected in tumor and in serum of C57BL/6 mice when the recombinant VACV was injected intratumorally (i.t.) in B16F10 and MCA 205 tumors. The concentration of circulating mAb detected after i.t. injection was up to 1,900-fold higher than the level obtained after a subcutaneous (s.c.) injection (i.e., without tumor), confirming the virus tropism for tumoral cells. Moreover, the overall tumoral accumulation of the mAb was higher and lasted longer after i.t. injection of the recombinant VACV than after i.t. administration of 10 µg of anti-mPD1. Interestingly, in the MCA 205 tumor model, the antitumoral activity of the VACV expressing mPD-1 is similar to the therapeutic efficacy of the combination of the unarmed VACV combined with a systemically administration of an anti-mPD-1 antibody and superior to that obtained with the unarmed VACV alone. These results pave the way for next generation of OV armed with immunomodulatory therapeutic molecules.

Citation Format: Laetitia Fend. Next generation of poxvirus-based immunotherapeutics [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B107.
Abstract B126: Degradation-regulatable architectured implantable macroporous scaffold for the spatiotemporal modulation of immunosuppressive microenvironment and enhanced combination cancer immunotherapy
Authors: Ren Long , Shin Il Woo , Song Chanyoung , Lim Yong Taik
Published: February 2019

The presence of immunosuppressive cells such as tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) in residual tumors after surgery is known to be related to high recurrence of tumors which are more resistant to therapeutic interventions compared with the primary ones. Herein, a degradation-regulatable architectured implantable macroporous scaffold (Dr-AIMS) is designed to act as a local drug delivery reservoir, modulating the immunosuppressive tumor microenvironment (TME) and activating T-cell-based antitumor immunity as well. The Dr-AIMS is fabricated by the crosslink of methacrylate-modified hyauronic acid under frozen state to form the interconnected macroprorous architacture with pore size of 252.36 ± 59.57 μm. By combining stable “bulk” material (methacrylate-modified hyaluronic acid) and hydrolytic-labile “sacrificing” component (methacrylate-modified oxidized hyaluronic acid) with varied blending ratios, the degradation can be regulated with 10-28 days after implantation in mice. In vitro results indicated that PTX could induce immunogenic 4T1 cell death and deplete TAMs, and R837 could activate antigen presenting cells and inhibit MDSCs functions. After loading PTX, R837 and combined immune checkpoint blockade molecules (anti-CTLA-4 and anti-OX40 mAbs, invigorating T-cells function), Dr-AIMS was implanted as postsurgical treatment (~10% remaining) in 4T1 breast tumor model. In vivo results suggested that the generation of systemic anti-tumor immunity required continuous drug supplies for at least two weeks. The sustained and localized supply of immunomodulatory drugs from Dr-AIMS facilitated the depletion of MDSCs and M2-like macrophages simultaneously within the tumor tissues, converting immunosuppressive TME into antitumor immunity niches. Also, enhanced infiltration of DCs and effector T-cells into tumor was observed, and systemic antitumor immunity was generated with 10-fold reduced doses, resulting in the prolonged survival of mice after surgery of incompletely removed tumor.

Citation Format: Long Ren, Il Woo Shin, Chanyoung Song, Yong Taik Lim. Degradation-regulatable architectured implantable macroporous scaffold for the spatiotemporal modulation of immunosuppressive microenvironment and enhanced combination cancer immunotherapy [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B126.
Abstract B133: Implantable synthetic immune hydrogel for spatiotemporal modulation of tumor-derived immunosuppression and systemic antitumor immunity
Authors: Song Chanyoung , Shin Il Woo , Ren Long , Lim Yong Taik
Published: February 2019

The development of biomaterial-based immune niches that can shape tumor-induced immunosuppressive factors will play an important role to improve current cancer immunotherapy. Herein, we developed an engineered 3-dimensional porous scaffold for creating synergistic action between myeloid-derived suppressor cell (MDSC)-depleting drugs, which can revert an immunosuppressive tumor microenvironment to one supporting antitumor immunity, and cancer vaccines (whole tumor lysate-based antigens and nano-adjuvants carrying Toll-like receptor 3 agonists), which can induce tumor antigen-specific T-cell responses. The local implantation of the scaffold (called immuneCare-DISC, iCD) as a post-surgical treatment in large established 4T1 breast tumors induced systemic antitumor immunity and prevented relapse and metastasis, resulting in survival of 100%. These therapeutic results were obtained from the depletion of MDSCs by control releasing of gemcitabine and the recruitment/activation of dendritic cells, increased infiltrating of T-cells and enhanced level of IFN-γ production by sustained releasing of cancer vaccine from the iCD. This synthetic immune niche iCD as a spatiotemporal modulation of tumor-induced immunosuppression and cancer vaccine-induced immune stimulation is proposed to generate favorable environment to prevent recurrence and metastasis following the surgical resection.

Citation Format: Chanyoung Song, Il Woo Shin, Long Ren, Yong Taik Lim. Implantable synthetic immune hydrogel for spatiotemporal modulation of tumor-derived immunosuppression and systemic antitumor immunity [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B133.
Abstract B140: Positron emission tomography-guided photodynamic therapy with biodegradable silica nanoparticles for personalized cancer immunotherapy
Authors: Xu Cheng , Moon James
Published: February 2019

Recent clinical trials with neoantigen-based vaccines have shown the feasibility and potential of personalized cancer immunotherapy. Photodynamic therapy (PDT), which utilizes photosensitizer and laser irradiation to produce reactive oxygen species, has been widely explored for local cancer treatment. In addition, positron emission tomography (PET) is a highly sensitive and noninvasive imaging method that can visualize solid tumors while allowing for quantitative analysis of drug biodistribution. In this work, we aimed to combine vaccination and PET imaging-guided PDT as an effective combination platform for personalized cancer immunotherapy. We have synthesized biodegradable silica nanoparticles (bMSN) loaded with neoantigen, CpG oligodeoxynucleotide (a potent Toll-like recetor-9 agonist) and chlorin e6 (a widely used photosensitizer). Using PET imaging, we have shown that bMSN effectively accumulates in MC-38 colon carcinoma tumors after intravenous administration in vivo. Subsequent PDT with 660 nm laser irradiation eliminated tumors, resulting in the release of tumor antigens and danger signals that promoted recruitment of dendritic cells to PDT-treated sites. The bMSN nanoplatform sustain-released neoantigen and CpG oligodeoxynucleotide, while activating DCs and enhancing neoantigen-specific cytotoxic CD8+ T-cell responses and their infiltration into tumors. In mice bearing two contralateral MC-38 tumors, the combination of vaccination and PDT completely eradicated locally treated, large MC-38 tumors while significantly delaying the growth of distant, untreated tumors. Our findings suggest that bMSN is a promising immunotherapeutic platform for combining imaging, vaccination, and PDT for treatment of advanced cancer.

Citation Format: Cheng Xu, James Moon. Positron emission tomography-guided photodynamic therapy with biodegradable silica nanoparticles for personalized cancer immunotherapy [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B140.
Abstract B143: Lace molecular vaccine with adjuvant booster to enhance immunogenicity
Authors: Yu Chunson , Liu Haipeng
Published: February 2019

Manipulation of vaccine adjuvants, including bioconjugation and particle formulation, is a prevailing approach to achieve efficient delivery and improve therapeutic efficacy. However, these approaches may compromise bioactivity or may not be desirable when these compounds are chemically or physically unmanipulable. Here, we report an “adjuvant booster” strategy to markedly promote immunogenicity by simply lacing molecular vaccines with an adjuvant booster. We created an adjuvant booster, lipid modified 20-mer thymidine oligodeoxynucleotide (lipo T20), which could significantly increase the potency of Toll-like receptor 7 (TLR7) ligands in both murine and human TLR7 HEK 293 cells and substantially target draining lymph nodes where unmodified adjuvant rarely accumulated. Subcutaneous administration of “imiquimod/protein antigen” vaccine laced with lipo T20 in mice resulted in a five-fold increase in T-cell priming and enhanced antibody response in comparison to booster-free vaccine. “Adjuvant booster” strategy provides an alternative and simple methodology to further enhance immunogenicity of molecular vaccines.

Citation Format: Chunson Yu, Haipeng Liu. Lace molecular vaccine with adjuvant booster to enhance immunogenicity [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B143.
Abstract B144: Morphologic consequences for noncapsular lymphoid tissue in the case of malignancy of GERD (Barrett's esophagus)
Authors: Azhken Bakhtiyar Talgatuly
Published: February 2019

In this case, the process of development of the Barrett's esophagus and the development of adenocarcinoma as a complication of this disease with involvement of lymphoid tissue with the formation of follicles of different types was studied. Barrett's esophagus (BE) is a precursor of adenocarcinoma of the esophagus, a disease with a growing burden in the Western world. The incidence of BE increased dramatically during the late 20th century and increased morbidity of this disease. Prevalence is between 0.5 and 2.0%. There are risk factors for BE, including obesity and tobacco smoking, but gastroesophageal reflux disease (GERD) is the strongest risk factor. Adenocarcinoma of the esophagus (ACE) is the most common form of esophageal cancer. However, the data from United Kingdom and the Netherlands show that the incidence of BE increased even after monitoring the increase in endoscopy indices. These estimates indicate an increase in the incidence of BE in approximately 65% between 1997 and 2002 and 159% between 1993 and 2005. It is disturbing that the greatest proportionate increase in the diagnosis of BE was in people younger than 60 years, which is consistent with other works from Europe. In analyzing the literature relating to the intrinsic glands of the esophagus and Barrett esophagus, concerned the esophagus's own glands and the presence of a large number of endocrine cells in them. N.I. Kolycheva, R.R. Bektayeva studied at ultramicroscopic level. When studying the work on the lymphoid formations of the esophagus, we can cite, concerning the lymphoid component of the esophagus. At present, the source of lymphocyte infiltration into its proper mucous plate, types of lymphoid formations, has not been studied. To study the lymphoid noncapsular formations of the mucous membrane of Barrett's esophagus, biopsy specimens of Barrett's esophagus were taken. Early only the epithelium of the esophagus was studied, but there was no evidence of a propria of the mucous membrane and lymphoid tissue.

Citation Format: Bakhtiyar Talgatuly Azhken. Morphologic consequences for noncapsular lymphoid tissue in the case of malignancy of GERD (Barrett's esophagus) [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B144.
Abstract B148: Microvilli enable efficient T-cell antigen search and ligand detection
Authors: Cai En , Marchuk Kyle , Beppler Casey , Krummel Matthew
Published: February 2019

During antigen detection, T-cells survey the surface of antigen-presenting cells (APCs), which may display mainly nonstimulatory peptide-loaded major histocompatibility complexes (pMHCs) and only rare cognate antigen in a process involving close (nanometer-scale) membrane apposition. Thus, T-cell must solve a classic trade-off between speed and sensitivity. It has long been supposed that microvilli on T-cells act as sensory organs to enable search, but their strategy has been unknown. We used lattice light-sheet microscopy and quantum dot-enabled synaptic contact mapping microscopy to show how microvilli on the surface of T-cells search opposing cells and surfaces before and during antigen recognition. We uncovered that microvilli on T-cell surfaces dynamically survey the majority of opposing surfaces within one minute through anomalous diffusion. T-cell receptor (TCR) recognition resulted in selective stabilization of receptor-occupied protrusions, which was independent of tyrosine kinase signaling and the actin cytoskeleton. We revealed that TCRs on activated T-cells were nonuniformly distributed on cell membrane: some TCRs were concentrated on microvilli, while other TCRs formed high-density patches on flatter membrane regions. Many microvilli were TCR-occupied, but a small population of microvilli were found not occupied by TCRs. TCR high-density patches moved relative to microvilli. During T-cell-APC interaction, we observed T-cell microvilli projected deep into 3D pockets formed by veil structures on the surface of dendritic cells (DC), and DC membrane also conformed to accommodate T-cell microvilli, which increased the effective close-contact area between T-cell and APC. Such scanning pattern enabled T-cells to efficiently scan more APC surface in given time. This work defines the efficienT-cellular search process against which ligand detection takes place in T-cells.

Citation Format: En Cai, Kyle Marchuk, Casey Beppler, Matthew Krummel. Microvilli enable efficient T-cell antigen search and ligand detection [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B148.
Abstract B152: Generation of monoclonal antibodies against a newly identified target for invasive prostate cancer and their use in the development of an antibody-based targeting therapy
Authors: Biase Anna Di , Regad Tarik , Vadakekolathu Jayakumar , Powe Desmond , Jäck Hans-Martin , Roth Edith
Published: February 2019

In 2013, cancer immunotherapy was selected as the breakthrough of the year by Science’s editors and monoclonal antibody therapy is considered one of its most successful tools. When castration-resistant prostate cancer (PCa) disease progresses and despite androgen deprivation treatment, it typically metastasizes, leading to poor patients’ prognosis and survival. In this case, immunotherapy represents the only chance of treatment. In a previous study carried out by our team on the role of cytoplasmic PML1 in the context of epithelial to mesenchymal transition (EMT) in PCa2, we identified a new promising PCa target for antibody-based therapy. Our target, of which we cannot disclose the name for patenting reasons and that we will further refer to as Protein-X, is a type 1 transmembrane protein that is specifically expressed by PCa cell. Transcriptome profiling obtained using Nanostring technology with a cancer progression panel showed that the knockdown of Protein-X leads to an upregulation of the epithelial EMT marker E-cadherin in PCa cells, suggesting its role in the process. Furthermore, the clinical value of Protein-X as a diagnostic and/or prognostic biomarker of invasive and aggressive PCa, is also being investigated by a histopathologist using immunohistochemistry analysis of Protein-X’s expression on tissue microarrays (TMAs). To develop a monoclonal antibody-based therapy against Protein-X, mouse monoclonal antibodies (mAbs) were generated using hybridoma technology. MAbs-producing hybridomas were sequenced and purified mAbs were tested for their specificity by flow cytometry, immunofluorescence, ELISA and immunoblotting assays. Using in vitro antibody-dependent cell-mediated cytotoxicity (ADCC) reporter assay, we show that the antibodies mediate cell cytotoxicity. This result will be further investigated in vivo using a xenograft mouse model. Future experiments will focus on designing and generating chimeric antigen receptor (CARs) modified adoptive T-cell targeting of Protein-X-expressing tumor cells and bispecific antibodies. In summary, we aim to develop an anti-Protein-X antibody-based therapy against invasive prostate cancer, which will potentially represent a new tool to target aggressive PCa responsible for cancer metastasis and poor prognosis in PCs patients.

Citation Format: Anna Di Biase, Tarik Regad, Jayakumar Vadakekolathu, Desmond Powe, Hans-Martin Jäck, Edith Roth. Generation of monoclonal antibodies against a newly identified target for invasive prostate cancer and their use in the development of an antibody-based targeting therapy [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B152.
Abstract B154: Differential effects of corticosteroids and anti-TNF on tumor-specific immune responses— Implications for the management of irAEs
Authors: Donia Marco , Borch Troels H. , Radic Haja D. , Chamberlain Christopher , Gokuldass Aishwarya , Svane Inge Marie Stentoft , Draghi Arianna
Published: February 2019

Background: Up to 60% of patients treated with cancer immunotherapy develop severe or life threatening immune-related adverse events (irAEs). Immunosuppression with high doses of corticosteroids or, in refractory cases, with tumor necrosis factor (TNF) antagonists, are the mainstay of treatment for irAEs. It is currently unknown what is the impact of corticosteroids and anti-TNF on the activity of antitumor T-cells. Methods: The influence of clinically relevant doses of dexamethasone (corresponding to an oral dose of 10 to 125 mg prednisolone) and infliximab (anti-TNF) on the activation and killing capacity of tumor-infiltrating lymphocytes (TILs) was tested in vitro. Results: Overall, dexamethasone at low or intermediate/high dose impaired the activation (respectively -46% and -62% in n=8) and tumor-killing ability (respectively -48% and -53% in n=6) of tumor-specific TILs. In contrast, a standard clinical dose of infliximab only had a minor effect on T-cell activation and tumor killing (respectively -20% in n=8 and -10% in n=6). A brief resting following exposure to dexamethasone was sufficient to rescue the in vitro activity of TILs. Conclusions: Clinically relevant doses of infliximab only influenced to a lesser extent the activity of tumor-specific TILs in vitro, whereas even low doses of corticosteroids markedly impaired the antitumor activity of TILs. These data support steroid-sparing strategies and early initiation of anti-TNF for the treatment of irAEs in immuno-oncology.

Citation Format: Marco Donia, Troels H. Borch, Haja D. Radic, Christopher Chamberlain, Aishwarya Gokuldass, Inge Marie Stentoft Svane, Arianna Draghi. Differential effects of corticosteroids and anti-TNF on tumor-specific immune responses— Implications for the management of irAEs [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B154.
Abstract B184: Modulating antigen flow to control immune tolerance
Authors: Ruhland Megan K. , Roberts Edward W. , Krummel Matthew F.
Published: February 2019

The immune system must maintain a delicate balance between activation and tolerance. It is required to quickly respond and eliminate a variety of threats while at the same time remain unresponsive upon encountering normal self-cells or commensal bacteria. We have created a system to track antigen trafficking throughout the immune system and using this system have identified a pathway of antigen flow from peripheral tissues and tumors to the draining lymph node (LN). By tracking antigen from steady-state tissues and tumors, we find that antigen is handled differentially in the LN depending on the inflammatory context in the periphery. During pronounced inflammation, self-antigen shows altered trafficking consistent with that of tumor antigen. Interestingly, using both gut and skin systems, commensal bacteria-derived antigen displayed the unique quality of cell type specific uptake. While each of the various migratory dendritic cell (DC) types were proficient at uptake of self and tumor antigens, only migratory CD11b+ DC and macrophages showed detectable commensal antigen uptake. Additionally, tracking of commensal bacteria-derived antigen within DC showed minimal antigen trafficking to the LN, suggesting different modes of maintaining immune tolerance are at play depending on the antigen source. We find that self-antigen can drain to the LN via migratory DC but is limited from passing to resident DC populations, which appears to prevent robust self-reactive T-cell priming. However, in the case of commensal antigen, the restriction of antigen flow is early in the pathway, thus effectively keeping the LN ignorant of antigen. Identifying the signals that restrict antigen flow in cases of immune tolerance will likely provide insight into how tumor antigen availability affects immune activation. Understanding how self, commensal and tumor antigens are handled by immune cells under various contexts will help inform the development of new targeted immunotherapies that seek to activate or inhibit immune activation in cases of cancer and autoimmunity.

Citation Format: Megan K. Ruhland, Edward W. Roberts, Matthew F. Krummel. Modulating antigen flow to control immune tolerance [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B184.