bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A199: TNFR2-targeted elimination of Tregs and tumor-residing T-cells in a murine colon cancer model
Authors: LaMontagne Russell
Published: February 2019

Introduction: Tumor necrosis factor receptor 2 (TNFR2, or TNFRSF1B) is a lymphoid marker of the most potent regulatory T-cell (Treg) subtype and a commonly expressed oncogene in human tumors. TNFR2 Tregs are also enriched in the tumor microenvironment. TNFR2 antagonistic antibodies have been developed to inhibit NFkB-driven growth through the TNFR2 receptor, showing both Treg and tumor inhibition with specificity for the tumor microenvironment (Sci Signaling 2017). A mouse surrogate, TY101, has been developed to assess efficacy in murine models of colon cancer. Methods: We designed monoclonal antibodies to target the TNFR2 oncogene and directly kill tumor cells in syngeneic murine models of colon cancer: CT26 and MC28. All studies were conducted by an independent third party (Champions Oncology). The primary endpoint was a reduction in tumor size. Results: In MC38 mice, the TNFR2 antagonist combined with anti-PD1 immunotherapy was more effective than placebo or immunotherapy alone in reducing mean tumor volume (P=0.004). In CT26 mice, the TNFR2 antagonist as a monotherapy was more effective compared to placebo or combination therapy with anti-PD1 (p<0.0001). Conclusions: The results of this study in syngeneic mice suggest that novel anti-TNFR2 antibodies have potential to be used either alone or in combination with immunotherapy as a treatment for colon cancer and should be studied in future trials.

Citation Format: Russell LaMontagne. TNFR2-targeted elimination of Tregs and tumor-residing T-cells in a murine colon cancer model [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 A199.
Abstract A206: Extracellular matrix anchoring of locally administered cytokines safely potentiates systemic cancer immunotherapy
Authors: Momin Noor
Published: February 2019

Cytokines coordinate essential mechanisms required for an antitumor response. As a result, they robustly synergize with other immunotherapies. Unfortunately, the clinical use and approval of cytokines is frequently plagued by dose-limiting toxicities. Improving the therapeutic index of cytokines can be achieved by better localizing their effects to the tumor and away from healthy tissue. Recent efforts have shown that local injections of immunomodulatory agents at or around a tumor lesion improve the efficacy and reduce the systemic exposure of these agents. However, even when administered directly into a tumor, cytokines exhibit rapid tumor clearance and limited intratumoral retention, thus doing little to address issues of toxicity and efficacy. Here we demonstrate that extracellular matrix (ECM) anchoring of intratumorally administered cytokines is a facile strategy to retain and confine these agents in the tumor. Although the ECM is an abundant component of both tumors and healthy tissue alike, intratumoral administration obviates the need to target a tumor-specific antigen. Instead, the abundance of matrix lends itself to being an effective and general target for localization across all solid tumors. ECM-anchoring of cytokines via fusion to a matrix-binding protein significantly improves their therapeutic index. Additionally, the combination of ECM-anchored cytokines with a systemic immunotherapy (e.g., a tumor-targeting antibody, checkpoint blockade, a cancer vaccine, or CAR-T-cell therapy) enhances overall survival in syngeneic tumor models compared to combination treatments using unanchored cytokines. Cytokines that are actively retained in the tumor can safely and significantly potentiate systemic immunotherapy. Given the abundant expression of ECM across different cancers, matrix-anchoring of cytokines embodies a tumor-agnostic strategy that can readily be combined with other immunotherapeutic modalities.

Citation Format: Noor Momin. Extracellular matrix anchoring of locally administered cytokines safely potentiates systemic 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 A206.
Abstract A212: Expanded CD8+PD-1+ T-cell and TCR repertoire signatured clinical response of adoptive T-cell immunotherapy in advanced pancreatic cancers
Authors: Qiao Guoliang
Published: February 2019

Purpose: Advanced pancreatic cancer(APC) has remained challenging to treat effectively. This study aimed to explore the biologic antitumor activities of sorted CD8+PD-1+T-cells expanded from peripheral blood mononuclear cells (PBMCs) and analyze the prognostic values of fold expansion capacity of functional CD8+PD-1+T-cells and TCR repertoire after ex vivo expansion. Experimental Design: 25 selected APC patients who had been previously confirmed with improved clinical response based on chemotherapeutic S-1 plus adoptive T-cell immunotherapy were further stratified to identify the biologically molecular mechanism of expanded CD8+PD-1+T-cell and restored TCR repertoire on post-infused patients’ peripheral blood T lymphocytes phenotype and subsequent association with clinical responses. Results: The harvested PMBCs were expanded ex vivo under the cytokines’ stimulation. The induced CD3+, CD3+CD4+, CD3+CD8+T-cells components reached the peak value in 15 days. CD8+T-cells exhibited enhanced expression of PD-1, LAG-3, and TIM-3 after ex vivo expansion except for 4-1BB. Survival analysis showed that patients with ratio of post/pre CD8+PD-1+T-cells more than 2 had significantly favorable overall survival (OS) (median OS time 238 days versus 142 days, P=0.024) and progressive-free survival (PFS) (median PFS time 180 days vs 85 days, P=0.002). The sorted CD8+PD-1+T-cells were featured by enhanced antitumor activities with the appearance of increased release of IFN-γ secretion and up-regulation of 4-1BB after co-culture with autologous tumor cell line. TCR repertoire diversity simultaneously rose during the ex vivo expansion in which increased unique clones could result in peripheral blood immunologically phenotypic improvements represented by CD8+ enhancement and CD8+/CD28- decline. Moreover, TCR increased unique clones were associated with significantly favorable OS (median OS time 216 days versus 112 days, P=0.031) and PFS (median PFS time 166 days vs 79 days, P=0.043) and the alteration of CD8+PD-1+T-cells (r2=0.464, P=0.001). Conclusion: This study showed that CD8+PD-1+T-cells after ex vivo expansion in 15 days could be identified as the tumor-reactive cells. The present discoveries were filled with that expanded CD8+PD-1+T-cells and restored TCR repertoire were significantly associated with clinical responses in APC.

Citation Format: Guoliang Qiao. Expanded CD8+PD-1+ T-cell and TCR repertoire signatured clinical response of adoptive T-cell immunotherapy in advanced pancreatic cancers [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 A212.
Abstract A214: An in vitro preclinical package to assess the safety and efficacy of ImmTAC™ molecules
Authors: Ribeiro Ana , Dobrzycki Tomasz , Harper Jane , Bossi Giovanna , Wright Debbie , Stacey Andrea , Bedke Nicole , Martinez-Hague Ruth , Blat Dan , Humbert Laure , Donellan Zoe , Paston Samantha , Weigand Luise , Canestraro Martina , Gordon-Smith Sophie Botta , Jakobsen Bent K. , Dukes Joseph
Published: February 2019

Immune Mobilising Monoclonal TCRs Against Cancer (ImmTAC) molecules are a new class of bi-specific biologic specifically designed to recognize and eradicate cancer cells. ImmTAC molecules are composed of an affinity-enhanced T-cell receptor (TCR) fused to an anti-CD3 effector function engineered to recognize peptides presented by human leukocyte antigen (HLA) and induce T-cell activation and T-cell mediated killing of tumor cells. TCR-based immunotherapeutic strategies offer distinct advantages over traditional antibody-based therapies, most notably providing access to up to nine-fold more cancer targets by targeting intracellularly processed peptides presented by HLA as opposed to cell surface proteins. Preclinical testing of ImmTAC molecules can prove particularly challenging as these molecules are exquisitely human-specific, requiring a human peptidome and intact human immune system; thus the use of conventional animal models is inappropriate. Given that these molecules harness the full force of the immune system, robust preclinical testing is essential to predict safety and efficacy and inform on clinical dosing for first-in-human studies. Here we present, to our knowledge, the first entirely in vitro preclinical package that comprises a range of cellular and molecular assays to assess the efficacy, safety and specificity of ImmTAC molecules. To exemplify our approach, we draw upon the preclinical testing of multiple ImmTAC molecules, including IMCgp100, the first ImmTAC molecule to reach the clinic. We propose that this preclinical package can be applied to the testing of other TCR-based therapies to deliver a more physiologically relevant model.

Citation Format: Ana Ribeiro, Tomasz Dobrzycki, Jane Harper, Giovanna Bossi, Debbie Wright, Andrea Stacey, Nicole Bedke, Ruth Martinez-Hague, Dan Blat, Laure Humbert, Zoe Donellan, Samantha Paston, Luise Weigand, Martina Canestraro, Sophie Botta Gordon-Smith, Bent K. Jakobsen, Joseph Dukes. An in vitro preclinical package to assess the safety and efficacy of ImmTAC™ molecules [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 A214.
Abstract A217: TCR affinity determines the fate of T-cells in tumors
Authors: Shakiba Mojdeh
Published: February 2019

T-cell-mediated immune responses are triggered by T-cell receptor (TCR) binding to peptide-major histocompatibility complex (pMHC). In acute infections, affinity of TCR:pMHC interaction is a critical determinant of T-cell expansion and effector function. However, little is known about how tumor (neo) antigen affinity impacts T-cell differentiation and dysfunction in tumors. To investigate the functional and molecular programs determined by affinity, we generated an in vivo tumor model expressing altered peptide ligands (APL) derived from a native tumor neoantigen recognized by antigen-specific CD8 T-cells with varying functional avidity. While affinity did not impact T-cell activation in tumor draining lymph nodes, it drove distinct functional and molecular pathways at the tumor site: key transcription factors and effector molecules were regulated by signal strength, preserving a cell-intrinsic functional program in T-cells with lower-affinity interactions, while certain hallmarks of T-cell dysfunction, including the expression of some inhibitory receptors, were affinity-independent. RNAseq and ATACseq analyses revealed distinct affinity-dependent transcriptional and epigenetic programs in low- vs. high-affinity T-cells that drive their functional differences. Together these results reveal that TCR:pMHC affinity plays a critical role in defining the epigenetic and transcriptional states and ultimately fate of tumor-specific T-cells.

Citation Format: Mojdeh Shakiba. TCR affinity determines the fate of T-cells in tumors [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A217.
Abstract A223: CD36-mediated metabolic adaptation guides regulatory T-cells in tumors
Authors: Wang Haiping , Ho Ping-Chih
Published: February 2019

Regulatory T-cells (Tregs) play an indispensable role in maintaining peripheral tolerance and preventing autoimmune disease. In addition to modulating tissue homeostasis, the suppressive properties of Tregs can also be harnessed by cancers to evade immunosurveillance. Therefore, depleting Tregs has been shown to unleash antitumor immunity and interrupt formation of an immunosuppressive tumor microenvironment (TME). However, systemic loss of Tregs due to Treg depletion also leads to severe autoimmunity. Therefore, the identification of novel approaches that specifically target intratumoral Tregs is direly needed for unleashing antitumor immunity and cancer immunotherapy. Here we show that intratumoral Tregs increase lipid uptake and content and elevated expression of CD36, a fatty acid translocase, as compared to Tregs in circulation and other normal tissues, in several cancer types. By using the transgenic mice model, we found that Treg-specific ablation of CD36 reduces accumulation of intratumoral Treg and suppresses tumor growth. Importantly, Treg-specific CD36 deficiency does not lead to autoimmunity in aged mice and CD36-deficient Tregs remain their suppressive activity on restraining CD4 T-cell-induced inflammatory bowl disease. Mechanistically, CD36 expression supports survival of intratumoral Tregs by fine-tuning their mitochondrial fitness via PPAR signaling. Thus, high expression of CD36 in intratumoral Tregs orchestrates Treg metabolic adaptation in tumors by intervening metabolic regulations, and further promotes tumor growth by suppressing the antitumor immune responses. Ultimately, anti-PD-1 blockade treatment elicits therapeutic benefits in mice with Treg-specific ablation of CD36. Altogether, our study suggests that CD36 might be a potential target for specifically waning down intratumoral Tregs and provide proof-of-concept evidence that targeting CD36 in tumors could unleash antitumor immunity and synergize with checkpoint blockade treatment.

Citation Format: Haiping Wang, Ping-Chih Ho. CD36-mediated metabolic adaptation guides regulatory T-cells in tumors [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A223.
Abstract B018: Landscape of natural HLA class I ligand peptides of cancer cells
Authors: Kikuchi Yasuhiro , Kanaseki Takayuki , Hongo Ayumi , Tokita Serina , Torigoe Toshihiko , Vitaly Kochin
Published: February 2019

HLA class I ligand repertoire on cancer cells directly influences immune surveillance system against cancer. We performed large-scale mass spectrometric profiling of the natural HLA-A*2402 ligand peptides and unveiled the landscape of natural HLA class I ligand peptides derived from various cancer cells including colon cancer cells (SW480, Colo320, HCT15) and lung cancer cells (LHK2, Sq-1). Known A24-binding anchors (Y/F at P2 and F/L/I at P9) were largely conserved among the ligands; however, a subset of peptides had an unusual anchor (K/R at the C-terminal P9 or P10), suggesting diverse usage of anchors in certain types of cancer cells. Moreover, a certain amino acid residue had significantly low frequency in the N-terminal flanking sequence, suggesting that it might inhibit processing of the peptides. Profiling of the natural HLA ligands of cancer cells revealed "neoantigen" peptides derived from mutated genome DNA and "aberrant antigen" peptides derived from long noncoding RNAs as well as "cancer-germ cell antigen" peptides. Among the natural HLA ligands derived from cancer cells, immunogenicity of the "neoantigen" peptide was the highest. The landscape clarified immunogenic peptide repertoire that might be suitable for cancer vaccine as well as as-yet-unknown rules for antigen processing.

Citation Format: Yasuhiro Kikuchi, Takayuki Kanaseki, Ayumi Hongo, Serina Tokita, Toshihiko Torigoe, Kochin Vitaly. Landscape of natural HLA class I ligand peptides of cancer cells [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B018.
Abstract B024: Using single-cell paired sequencing to isolate cancer-specific T-cell receptors for cancer immunotherapy
Authors: Lech Karolina , Correia Lucia , Beckmann Max , Busz Maria , Collison Sean , Davis Sterenn , Mallini Paraskevi , Scaife Sarah , Dukes Joseph , Jakobsen Bent K. , Williams Luke , Teng Michelle
Published: February 2019

Immunocore’s ImmTAC™ (Immune Mobilising Monoclonal TCR Against Cancer) platform combines affinity-enhanced T-cell receptor (TCR)-based targeting with an anti-CD3 scFv effector function to activate a cytotoxic T-cell response against cancer cells. A key part to this process is the identification of tumour epitope specific TCRs from tumor antigen-reactive T-cells. Here, we describe an integrated in-house process leading to the isolation of TCRs specific for validated cancer epitopes, coupled with rapid identification of TCR chains from individual clones using single cell sequencing. The process involves first strand cDNA generation and universal amplification using SmartSeq2 chemistry, followed by targeted sequencing of the TCR alpha and beta chains using next-generation sequencing (NGS). We have also leveraged the 10x Genomics VDJ/5’ counting platform to label and pool multiple experimental clones for repertoire sequencing within a single run. Together with Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-Seq), we can reliably assign each T-cell clone to its sample of origin paired with transcriptomic information of epitope specific T-cell populations, linking TCR sequences to their functional phenotype.

Citation Format: Karolina Lech, Lucia Correia, Max Beckmann, Maria Busz, Sean Collison, Sterenn Davis, Paraskevi Mallini, Sarah Scaife, Joseph Dukes, Bent K. Jakobsen, Luke Williams, Michelle Teng. Using single-cell paired sequencing to isolate cancer-specific T-cell receptors for 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 B024.
Abstract B044: Engineering CAR NK cells for antigen-dependent autocrine expansion
Authors: Shemesh Avishai , Roybal Kole T. , Lanier Lewis L.
Published: February 2019

Given promising results with chimeric antigen receptor (CAR) T-cell therapy in hematologic malignancies attention has turned to whether CAR natural killer (NK) cells might have utility in cancer immunotherapy. NK cells are known to have potent cytolytic function and the ability to secrete interferons and cytokines, including GM-CSF and interferon-γ (IFNγ) upon stimulation. In pre-clinical models CAR NK cells have been shown to have efficacy and possibly some advantages over CAR T-cells. Several biotechs and pharmas are currently exploring this approach, but a major limitation of NK cells is their inability to produce autocrine growth factors to promote their own expansion and activation. In the context of CAR NK cell therapy, a major limitation is the inability of the infused CAR NK cells to expand in the absence of cytokine signals to initiate their proliferation and enhance their effector functions. IL-12 and IL-15 are essential for the clonal expansion of NK cells; however, recombinant IL-12 and IL-15 are quite toxic when administered systemically. Additionally, engineering NK cells to constitutively secrete IL-12 or IL-15 is not an attractive strategy as this may also result in off-target toxicity. Our goal is to engineer chimeric receptors with the intracellular signaling domains of IL-12 or IL-15 receptors fused to the extracellular domains of cytokine receptors. Consequently, self-secreted cytokines by activated NK cells or recognition of tumor cells will provide autocrine growth signal, permit NK clonal expansion and enhance NK effector functions.

Citation Format: Avishai Shemesh, Kole T. Roybal, Lewis L. Lanier. Engineering CAR NK cells for antigen-dependent autocrine expansion [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 B044.
Abstract B048: Proteomic approaches for the identification of druggable protein and epigenetic targets to complement melanoma immunotherapy
Authors: Tackett Alan
Published: February 2019

Introduction: Immune checkpoint inhibitors (ICIs) have shown encouraging success for treatment of melanoma; however, approximately half of patients with advanced melanoma have primary ICI resistance and sub-populations of initially responding patients develop secondary resistance. To help address this, our group has used quantitative proteomic workflows to identify druggable molecular pathways in these non-responders. Specifically, we are targeting the identification of protein pathways involved in regulation of gene transcription and chromatin modification as these are upstream events in cellular programming. Experimental Procedures: We have used cutting-edge proteomic workflows to identify proteins and histone post-translational modifications that are dysregulated in ICI nonresponsive patient melanoma. Proteins were isolated from FFPE patient melanomas and analyzed by high-resolution mass spectrometry with a Thermo Fusion Orbitrap mass spectrometer. Mass spectrometric data was searched for proteins and histone post-translational modifications dysregulated in ICI nonresponding melanomas. Pathway analysis provided for the identification of molecular pathways dysregulated in ICI nonresponders. New Data: We have published a smaller-scale version of this proteomic study comparing 4 responding and 4 nonresponding melanomas (Sci Reports 2017;7:807). In new data, we have increased the sample size of this comparison to provide increased power and significance. We have also expanding our quantitative proteomic analysis by incorporating the use of Thermo Tandem Mass Tagging with FFPE samples. Furthermore, we present new workflows using fresh melanoma tumors that provide for specific enrichment of melanoma cells from human tumors. Conclusions: We have identified protein and histone epigenetic pathways that are dysregulated in ICI nonresponsive patient melanomas. These molecular pathways could be prime targets for therapeutic development for increasing responsiveness to ICI therapy. Furthermore, we have extended our proteomic capabilities to the analysis of enriched populations of melanoma cells isolated from fresh human tumors, which will provide for cell type-specific proteomic studies.

Citation Format: Alan Tackett. Proteomic approaches for the identification of druggable protein and epigenetic targets to complement melanoma 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 B048.
Abstract B050: Identification of PD-1T TILs and CXCL13 as determinants for response to anti-PD-1 treatment using human tumor explants
Authors: Thommen Daniela S. , Koelzer Viktor H. , Herzig Petra , Bruijn Marjolein de , Voabil Paula , Braber Marlous van den , Hummelink Karlijn , Monkhorst Kim , Mertz Kirsten D. , Zippelius Alfred , Haanen John B.A.G. , Schumacher Ton N.M.
Published: February 2019

Reinvigoration of tumor-specific T-cells by cancer immunotherapies, in particular PD-1/PD-L1 blocking agents, has greatly improved clinical outcome in multiple cancer types. Nevertheless, durable clinical benefit is currently limited to a small number of patients. To achieve a better understanding of the immunologic determinants of response to anti-PD-1 therapy, we assessed transcriptional and functional profiles of tumor-infiltrating lymphocyte (TIL) subsets from non-small cell lung cancer specimens. Thereby, we identified a transcriptionally distinct CD8 TIL pool with enriched capacity for tumor recognition. This TIL pool, termed PD-1T TILs, is characterized by bright PD-1 expression and constitutive CXCL13 secretion, which can mediate immune cell recruitment to tertiary lymphoid structures. Notably, the presence of PD-1T TILs correlates with response and survival in a small cohort of lung cancer patients treated with PD-1 blockade. To assess the role of PD-1T TILs and CXCL13 for response to PD-1 blockade in other cancer types, we developed a platform using human tumor explants to visualize immunologic responses to anti-PD-1 on a patient-specific level. Analysis of the cellular and soluble tumor microenvironment composition as well as of treatment-induced changes in tumor-infiltrating immune cells revealed immunologic responses to anti-PD-1 in 5 different cancer types. Of note, responding tumors in different tumor types were characterized by a clear enrichment in both PD-1T TILs and CXCL13 production. Collectively, our data reveal a distinct state of PD-1 bright lymphocytes that are enriched for tumor-reactivity in human cancer, making them an attractive proxy for the antitumor potential of the intratumoral T-cell pool. Furthermore, we established technology using human tumor explants to measure the immunologic response to T-cell checkpoint inhibition on a personalized basis. Finally, with this approach we identified PD-1T TILs and CXCL13 as determinants for response to anti-PD-1 in multiple cancer types, opening potential new avenues for therapeutic intervention and improved patient selection.

Citation Format: Daniela S. Thommen, Viktor H. Koelzer, Petra Herzig, Marjolein de Bruijn, Paula Voabil, Marlous van den Braber, Karlijn Hummelink, Kim Monkhorst, Kirsten D. Mertz, Alfred Zippelius, John B.A.G. Haanen, Ton N.M. Schumacher. Identification of PD-1T TILs and CXCL13 as determinants for response to anti-PD-1 treatment using human tumor explants [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 B050.
Abstract B055: Enhanced detection of T-cells targeting unique neoantigens and shared mutated oncogenes for personalized cancer immunotherapy
Authors: Yossef Rami , Tran Eric , Gros Alena , Deniger Drew , Cafri Gal , Rosenberg Steven A.
Published: February 2019

Adoptive cell transfer (ACT) of selected tumor-infiltrating lymphocytes (TILs) targeting neoantigens can mediate tumor regression in selected patients with metastatic epithelial cancer. However, effectively identifying and harnessing neoantigen-reactive T-cells for patient treatment remains a challenge and it is unknown whether current methods to detect neoantigen-reactive T-cells are missing potentially clinically relevant neoantigen reactivities. We thus investigated whether the detection of tumor-neoantigen reactive TILs in epithelial cancers could be enhanced by enriching T-cells that express PD-1 and/or T-cell activation markers (CD134, CD137) followed by microwell culturing at limiting dilution cell concentrations to avoid overgrowth of non-reactive T-cells. Using this approach, in six patients with metastatic epithelial cancer including stomach, colon pancreatic and ovarian cancers, this method led to the detection of CD4 and CD8 T-cells targeting 19 neoantigens compared to only eight neoantigens recognized using our standard TIL fragment screening approach. In two patients, no recognition of mutated peptides was observed using our conventional screen, while our high-throughput approach led to the identification of five neoantigen reactive-TCRs against five different mutations from one patient and a highly potent MHC-II-restricted KRASG12V reactive TCR from a second patient. In addition, in a metastatic tumor sample from a patient with serous ovarian cancer, we isolated three MHC class-II-restricted TCRs targeting the TP53G245S “hot-spot” mutation. In conclusion, this approach provides a highly sensitive and specific platform to isolate clinically relevant neoantigen-reactive T-cells or their TCRs for cancer treatment.

Citation Format: Rami Yossef, Eric Tran, Alena Gros, Drew Deniger, Gal Cafri, Steven A. Rosenberg. Enhanced detection of T-cells targeting unique neoantigens and shared mutated oncogenes 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 B055.
Abstract B060: Commensal bacteria Bifidobacterium stimulates an antitumor response via cross-reactivity
Authors: Bessell Catherine Ami
Published: February 2019

While recent studies have shown an important role of the microbiome in modulating anti-tumor immune responses, its mechanism remains unclear. One proposed mechanism is due to cross-reactivity between antigens expressed in commensal bacteria and neoepitopes found in tumors. We have identified a cross-reactive antigen expressed in commensal bacteria Bifidobacterium (Bifido.) “SVYRYYGL” (henceforth called SVY) and show that it conveys a neoantigen-specific cross-reactivity to the classic neoantigen “SIY.” The SVY-specific response was analyzed through biophysical experiments and molecular dynamics simulations, which showed that the SVY peptide bound the H2-Kb MHC (Kb) with an altered peptide configuration leading to a cross-reactivity but at a lower overall affinity for the transgenic, SIY-specific 2C T-cell receptor (TCR). By T-cell expansion studies, commensal bacteria SVY-specific T-cells populations have a cross-reactive SIY specific T-cell response and those T-cell populations can recognize tumors expressing the “SIY” antigen. Mice lacking Bifido. have a decreased commensal bacteria specific T-cell response and an altered TCR repertoire compared to Bifido. colonized animals. Moreover, Bifido. colonization not only shapes the SVY commensal bacteria-specific T-cell repertoire but selects for clones that are represented in the SIY T-cell repertoire. Cross-reactive SVY-specific T-cells recognize tumors bearing SIY in vivo in an adoptive T-cell transfer model and a murine melanoma model. Animals treated with cross-reactive SVY-specific T-cells had decreased tumor growth and extended survival. Our work demonstrates that commensal bacteria can directly stimulate antitumor immune responses via T-cell cross-reactivity and provides a proof of principle for how bacterial antigens can shape the T-cell landscape.

Citation Format: Catherine Ami Bessell. Commensal bacteria Bifidobacterium stimulates an antitumor response via cross-reactivity [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 B060.
Abstract B067: Distinct necessity of mitochondrial complex I and III for regulatory T-cell function
Authors: Steinert Elizabeth M. , Weinberg Samuel E. , Chandel Navdeep S.
Published: February 2019

Regulatory T-cells (Treg cells) are major mediators of immunological homeostasis and tolerance, and their actions suppress responses to self-antigens that are aberrant as well as anti-tumor. Recent studies have demonstrated that, relative to other CD4+ T-cell subsets, Treg cells display increased mitochondrial metabolism and the Treg cell lineage-defining transcription factor, FOXP3, promotes respiration. However, it remains unknown whether Treg cells require the mitochondrial respiratory chain for their suppressive capacity, lineage stability, or survival. Our lab recently found that constitutive Treg cell-specific ablation of mitochondrial respiratory chain complex III but not complex I resulted in the development of a fatal inflammatory disease early in life. Treg cells lacking complex III survived and maintained proliferative capacity, but displayed a loss of suppressive function. We found that in adults, tamoxifen induced deletion of mitochondrial complex III or complex I from Treg cells impaired tumorigenesis. Surprisingly, only loss of complex III resulted in the development of fatal inflammatory disease. Because mitochondrial complex I inhibitors are being explored for cancer treatments, we are investigating the mechanism by which loss of complex I activity in Tregs prevents tumorigenesis.

Citation Format: Elizabeth M. Steinert, Samuel E. Weinberg, Navdeep S. Chandel. Distinct necessity of mitochondrial complex I and III for regulatory T-cell function [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 B067.
Abstract B068: Vitiligo and melanoma: The role of cutaneous human commensal bacteria in antimelanocyte immune responses
Authors: Vujkovic-Cvijin Ivan
Published: February 2019

Immunotherapies designed to bolster endogenous immune responses against tumors, in the form of checkpoint blockade, have vastly improved survival for a host of cancers. However, despite these novel approaches, metastatic melanoma remains associated with high mortality and rapid progression, and a subset of patients do not respond robustly to checkpoint blockade. Development of new methods to boost endogenous immune responses against melanoma thus constitutes a critical step toward the management of disease. Of note, initiating immune responses against nonmutated melanocyte-specific protein antigens has shown efficacy in augmenting immunotherapies. Vitiligo is an autoimmune disease characterized by immune-mediated destruction of melanocytes, though the etiology of this disease remains poorly understood. Skin-resident microbes have been recently demonstrated to exert a profound effect on immune processes of the skin, including those that are associated with vitiligo progression. Identifying skin-resident microbes that initiate or exacerbate antimelanocyte immune responses, as well as the precise pathways that mediate these processes, may provide a novel framework for the development of immunotherapies to augment antimelanoma immune responses. Thus, we have recruited a cohort of individuals with and without vitiligo and profiled their skin microbiomes at various body sites. We have found that vitiligo subjects harbor a skin microbiota that is unique from healthy subjects, and have isolated several vitiligo-associated bacteria. Notably, a previously uncultured Corynebacterium species appears in greater abundance on vitiligo subjects than on control subjects. The immunomodulatory potential of this novel bacterium will be explored in murine models developed by our laboratory, including an adapted mouse model of vitiligo. Interrogation of this host-microbiome relationship may thus lead to the identification of novel targets and pathways by which to treat vitiligo and augment melanoma immunotherapies.

Citation Format: Ivan Vujkovic-Cvijin. Vitiligo and melanoma: The role of cutaneous human commensal bacteria in antimelanocyte immune responses [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 B068.
Abstract B087: MHC class II on cancer cells—Role in response to BCG therapy of bladder cancer
Authors: Redelman-Sidi Gil , Glickman Michael , Binyamin Anna , Antonelli Anthony
Published: February 2019

BCG, a live mycobacterium also used worldwide as a vaccine against tuberculosis, is one of the first successful immunotherapies of cancer. Despite being in clinical use for the treatment of non-muscle-invasive bladder cancer (NMIBC) for 4 decades, the mechanism by which BCG activates the immune system to destroy cancer cells is poorly understood and there are no reliable methods to predict a patient’s response to BCG treatment. Current data suggest that the efficacy of BCG depends on initial attachment of BCG to bladder cancer cells leading to activation of an immune response that is T-cell dependent. It is not known whether bladder cancer cells have a direct role in activating T-cells. Using an orthotopic mouse model of BCG treatment of bladder cancer we show that: 1) BCG induces tumor-specific immunity; 2) CD4+ T-cells are the main requirement for BCG efficacy and for the tumor-specific immunity engendered by BCG therapy;3) bladder cancer cells can directly activate CD4+ T-cells; 4) the efficacy of BCG depends on MHC class II expression on the surface of bladder cancer cells. These data suggest that bladder cancer cells directly activate and drive a CD4+ T-cell dependent immune response that is required for the efficacy of BCG. Current work in the lab is focused on characterizing MHC class II expression on human NMIBC specimens and determining whether expression of MHC class II on bladder cancer cells predicts clinical outcomes after BCG therapy.

Citation Format: Gil Redelman-Sidi, Michael Glickman, Anna Binyamin, Anthony Antonelli. MHC class II on cancer cells—Role in response to BCG therapy of bladder cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B087.
Abstract B093: Development of prediction software PrDx, trained on peptide-MHC stability assays, shows new important positions in the binding patterns of the peptides-MHC I and II complexes
Authors: Thorgrimsen Stephan , Justesen Sune , Rapin Nicolas
Published: February 2019

Mutations in cancer cells may lead to the formation of neo-epitopes potentially presented by both major histocompatibility complex (MHC) class I or II. These neo-epitopes may be recognized by CD8+ or CD4+ T-cells, and trigger an immune response. Only a small fraction of the neoepitopes will be displayed by the MHC class I or II. One of the challenges of cancer immunotherapy is therefore to predict which neoepitopes are susceptible to elicit a T-cell response. Software tools such as netMHC, MHC Flury and many others are over-predictive as the bulk part of the data used to train these methods are based on affinity assays. Several publications have indicated that stability assays may provide data that better correlate with epitope presentation by MHC. Prediction tools trained on stability assays may therefore be better at selecting neoepitopes resulting in more effective cancer vaccine design. We performed stability assay measurements for 10 MHC class I and 10 MHC class II alleles using a peptide scan library approach. In brief, random 9-mers where one position is known were used to measure stability of the peptide MHC complex. Next, the data were used to train a prediction tool, PrDx, that relies on a combination of different machine learning methods (random forest, feed forward neural networks and recurrent neural networks), of which the outputs are gathered in an assemble model. The model was then further trained with peptides predicted to bind with high stability, to the MHC alleles, until satisfactory performances were attained. To our surprise, PrDx showed new binding patterns for the alleles we trained. Although mostly similar to the binding patterns seen with affinity data trained method, the stability trained method is able to show new important positions in the binding patterns of the peptide-MHC complexes. Through retrospective analysis, our method seems able to select more accurately peptides susceptible to elicit a T-cell response, compared to state-of-the-art epitope prediction methods. Our results suggest that PrDx may be an attractive prediction tool for neo-epitopes discovery.

Citation Format: Stephan Thorgrimsen, Sune Justesen, Nicolas Rapin. Development of prediction software PrDx, trained on peptide-MHC stability assays, shows new important positions in the binding patterns of the peptides-MHC I and II complexes [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 B093.
Abstract B116: Nano-neo-mRNA vaccine: A novel platform technology for cancer-immunotherapy
Authors: Koyakutty Manzoor , Ramesh Navyashree A. , Nambiar Ashwathy , Anna Najuma Nujum Ambili , Abraham Manju C. , Anoop Minu , Ramkumar Anjana , Shanti Nair , Harish Vijay Harish , Ashokan Anusha
Published: February 2019

Nanoparticle-based immunotherapeutic platforms are emerging as radically different, biocompatible alternatives for viral-vectors. Liposomal nanoplexes already showed potential for clinical translation of mutanome specific personalized cancer-vaccines in human. Here, we report a novel nanoparticle platform technology for neoantigen specific mRNA (neo-mRNA) vaccine delivery and demonstrated its potential for evoking T-cell mediated immune response against drug/radiation resistant glioma cells. Glioblastoma multiforme (GBM) is one of the most aggressive type primary brain tumors with high rate of recurrence and poor prognosis. Temozolomide (TMZ) chemotherapy in concurrence with radiation is less effective for patients with over-expression of DNA repair protein, O6-methyl guanine-DNA methyltransferase (MGMT) or epidermal growth factor receptor variant III (EGFRvIII) mutation. Here, we developed a unique pathogen mimicking nanoparticle platform that can effectively encapsulate and transfect dendritic cells with mRNA vaccine specific to MGMT or EGFRvIII. MGMT/EGFRvIII mRNA was synthesized by in vitro transcription (IVT) from respective cDNA plasmid and 100-150nm sized nanoplex was formed with mRNA at the core with >90% encapsulation efficiency. This Nano-neo-mRNA vaccineTM platform was successfully delivered to human monocyte derived DCs with a transfection efficiency of 35-50% compared to 3-5% in the case of naked mRNA. The transfected DCs showed significant phenotypic expression of MGMT-GFP with MHC I/II and CD80/86 co-activation compared to the naked mRNA or vehicle control. The efficiency of vaccinated DCs to prime cytotoxic T-cells was demonstrated in co-cultures where the nanoplex showed efficient activation of T-cell-mediated cytotoxicity on MGMT or EGFRvIII expressing, TMZ/radiation resistant glioblastoma cells . Biocompatibility of the nano-carrier was demonstrated in primary human cells and animal models. Thus, we present a new, biocompatible nanoparticle platform technology for IVT-mRNA based cancer-immunotherapy.

Citation Format: Manzoor Koyakutty, Navyashree A. Ramesh, Ashwathy Nambiar, Najuma Nujum Ambili Anna, Manju C. Abraham, Minu Anoop, Anjana Ramkumar, Nair Shanti, Vijay Harish Harish, Anusha Ashokan. Nano-neo-mRNA vaccine: A novel platform technology for 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 B116.
Abstract B119: DC-recruiting biomaterial vaccine to enhance antitumor immunity
Authors: Li Aileen W. , Dellacherie Maxence O. , Sobral Miguel , Ali Omr O. , Kim Jaeyun , Mooney David J.
Published: February 2019

Biomaterials have shown substantial potential to integrate synergistically with current cancer vaccine strategies and enhance their effectiveness. We recently developed an injectable biomaterial vaccine via spontaneous assembly of mesoporous silica (MPS) microparticles into a 3D scaffold in vivo. When formulated with GM-CSF and the TLR-9 agonist CpG, the MPS vaccine modulates host dendritic cell (DC) activation and trafficking. Here we demonstrate that a single injection of the MPS vaccine induced persistent germinal center B cell activity for over 30 days. Consequently, when immunized with a small linear Her2/neu peptide within the Trastuzumab binding domain, the MPS vaccine elicited over 2 orders of magnitude higher IgG1 and IgG2a antibody titer compared to a traditional bolus vaccine, and the antibody exhibited immunoreactivity on the native Her2 structure on breast cancer cells. To further enhance CTL responses against tumor antigens, we co-presented the antigen with polyethylenimine (PEI) in the MPS vaccine. PEI increased antigen cross-presentation in murine DCs, and TNF-a and IL-6 production in both murine and human DCs in vitro. Compared to the MPS vaccine, the MPS-PEI vaccine enhanced activated and antigen+ DCs in the vaccine and the vaccine draining lymph node by ~2 fold. Systemically, using both OVA and a HPV-E7 peptide as antigens, the MPS-PEI vaccine induced ~2.5 fold higher IFN-y producing antigen specific circulating CD8+ T-cells compared to the MPS vaccine. Impressively, using a HPV-E7 expressing tumor model, we demonstrated that a single injection of the MPS-PEI vaccine completely eradicated large established tumors in over 80% of mice. Finally, when immunized with a pool of recently sequenced B16 melanoma neoantigen peptides, the MPS-PEI vaccine induced potent therapeutic tumor growth control and synergy with anti-CTLA4 checkpoint blockade therapy. These findings suggest that the MPS vaccine may serve as a facile multifunctional and multi-epitope platform to modulate host immune cell function and augment personalized antitumor immunity.

Citation Format: Aileen W. Li, Maxence O. Dellacherie, Miguel Sobral, Omr O. Ali, Jaeyun Kim, David J. Mooney. DC-recruiting biomaterial vaccine to enhance 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 B119.
Abstract B120: TIPE2 regulates apoptosis and autophagy to inhibit tumorigenesis in colon cancer
Authors: Li Jun , Xia Xiaoli
Published: February 2019

TIPE2 is an important immune negative regulator which regulates innate immunity and adaptive immunity to maintain immune homeostasis. Abnormal expression of TIPE2 is related to many acute and chronic inflammatory diseases, as well as the tumorigenesis. Here, we identified that overexpression of TIPE2 in colon cancer cell line inhibited cell growth. Recombinant adenovirus-expression TIPE2 effectively inhibited the proliferation of several kinds of cancer cell. Using protein biochip ananlysis, we found that in the TIPE2-overexpressing colon cancer cell, the expression levels of phosphorylated p38-MAPK/JNK, pro-apoptotic survivin were downregulated. These results suggest TIPE2 regulates tumor cell growth though p38-MAPK/JNK pathway. Western blot analysis showed that the proliferation level of AKT and the expression level of Bad were also changed in the TIPE2-overexpressing colon cancer cell, suggesting that TIPE2 may inhibit tumor cell proliferation through inducing cell death. Using flow cytometry analysis, we found that the overexpression of TIPE2 could promote apoptosis of tumor cell while knockdown of TIPE2 expression by shRNA could inhibit apoptosis. Previous studies have demonstrated that p38-MAPK/JNK and Akt pathway play important roles in autophagy. In this study, with the accumulation of LC3-II by stimulating TIPE2, tumor autophagy was increased in vitro. Thus, the function of TIPE2 in the inhibition of tumorigenesis may have broad implications in cancer gene therapy.

Citation Format: Jun Li, Xiaoli Xia. TIPE2 regulates apoptosis and autophagy to inhibit tumorigenesis in colon cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B120.