bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1523: Cell Squeeze® delivery of antigen-encoding mRNA enables human PBMCs to drive antigen-specific CD8+ T cell responses for diverse clinical applications
Authors: Maloney Michael F. , Ozay Emrah Ilker , Yee Christian , Merino Amy , Dunbar Paul R. , Mosaheb Mubeen , Volk Kelly , Smith Carolyne , Seidl Katherine J. , Bernstein Howard , Loughhead Scott M. 
Published: July 2021

Abstract
Antigen-specific CD8+ T cell priming is critical for mounting an effective immune response against altered self or foreign antigens that are found in most tumors and virally infected cells. T cell priming events require antigen presenting cells (APCs) to process and load antigenic peptides onto MHC molecules. One recently established method for providing APCs with foreign antigen is through delivery of mRNA. An advantage of using antigen-encoding mRNA, compared to protein or peptides, is the inherent protein amplification of mRNA translation; a single mRNA can be translated multiple times. In addition, when antigen-encoding mRNA is delivered directly to the cell, the antigens will have the appropriate post-translational modifications, potentially increasing the immunogenicity. Whereas typical mRNA vaccine platforms require modified nucleotides and lipid nanoparticle encapsulation, Cell Squeeze® technology allows for delivery of uncomplexed and unmodified mRNA directly into the cytosol.
Here, we use ex vivo microfluidic Cell Squeeze® technology to deliver uncomplexed and unmodified mRNA encoding for disease related antigens into human peripheral blood mononuclear cells (PBMCs) to generate PBMC APCs. We demonstrate that squeezing PBMCs with mRNA results in effective delivery and translation of mRNA in major cell subsets including T cells, B cells, NK cells, and monocytes. Delivery of antigen-encoding mRNA to human PBMCs enables them to function as APCs, capable of presenting antigenic peptides on MHC molecules for activation of antigen-specific T cells. Specifically, we demonstrate squeezing antigen-encoding mRNA (e.g. HPV16 E7) into human PBMCs results in PBMC APCs that can elicit robust in vitro activation of antigen-specific CD8+ T cells. This approach to APC engineering demonstrates Cell Squeeze® technology's potential to leverage the modularity, cost-effectiveness, and streamlined manufacturing of multiple mRNAs to create cellular vaccines for treating various tumor and infectious disease targets.
Citation Format: Michael F. Maloney, Emrah Ilker Ozay, Christian Yee, Amy Merino, Paul R. Dunbar, Mubeen Mosaheb, Kelly Volk, Carolyne Smith, Katherine J. Seidl, Howard Bernstein, Scott M. Loughhead. Cell Squeeze® delivery of antigen-encoding mRNA enables human PBMCs to drive antigen-specific CD8+ T cell responses for diverse clinical applications [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1523.
Abstract 1540: CARs and TCRs: Myth and reality
Authors: Wang Xueyin , Martin Aaron D. , Negri Kathleen , McElvain Michele , Oh Julyun , Wu Ming-Lun , Lee Wen-Hua , Hamburger Agnes , Xu Han , Kamb Alexander 
Published: July 2021

Abstract
Here we address questions of comparative TCR and CAR function: How different are CARs from TCRs with regard to antigen sensitivity, selectivity, co-stimulation dependence, checkpoint control, cytokine sensitivity, and antigen-dependent exhaustion (defined as loss of cytotoxicity and proliferative capacity over time). We used optimized CARs and TCRs matched to the same target pMHCs, allowing direct comparison of these important parameters. We describe a large-scale, systematic comparison of 17 CARs and 5 TCRs directed at 5 different pMHC targets in both acute and chronic settings in vitro. Surprisingly, we find little fundamental difference between CARs and TCRs with respect to their relative sensitivity to known regulators of T cell activation, including co-stimulation, checkpoint, and cytokine control. Though TCRs often emerge from human blood directly as potent, selective receptors, CARs must be heavily optimized to attain these properties for pMHC targets. Nonetheless, when iteratively improved, CARs can achieve levels of sensitivity and selectivity similar to their vaunted counterparts. Thus, other than signaling sensitivity (and perhaps selectivity), there may be little to distinguish CARs from TCRs in the context of engineered-cell therapy. CARs appear similar to TCRs with regard to immune control, undermining the notion that CARs can, of themselves, overcome regulators that limit T cell activity. Nevertheless, CARs tolerate much more sequence variability within their structural components and this, coupled with their capability to bind different antigen classes, smaller size and subunit simplicity, confers advantages that may foster a leading role for CARs in the next generation of cell therapeutics. We believe that the major conclusions reached here should instruct thinking about the boundaries around therapeutic designs for CARs, which appear to be very wide, and those around differentiation from TCRs, which appear to be much narrower.
Citation Format: Xueyin Wang, Aaron D. Martin, Kathleen Negri, Michele McElvain, Julyun Oh, Ming-Lun Wu, Wen-Hua Lee, Agnes Hamburger, Han Xu, Alexander Kamb. CARs and TCRs: Myth and reality [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1540.
Abstract 1541: Incorporation of an IgG4-derived spacer improves the activity of nanobody-based CAR T cells targeting a membrane-distal epitope of glypican 1 in pancreatic cancer
Authors: Li Nan , Li Dan , Pan Jiajia , Ho Mitchell 
Published: July 2021

Abstract
Background & Aims: Epitope recognition and antigen density have emerged as major parameters affecting the anti-tumor activity of chimeric antigen receptor (CAR) T cells. Glypican 1 (GPC1) is a cell surface proteoglycan that is expressed in pancreatic cancer. Here, we investigate how the choice of an epitope and an extracellular spacer in CAR design can determine T cell activation in high- or low- GPC1-expressing tumors.
Methods: We use mouse hybridoma and phage display technologies to isolate GPC1-specific antibodies or nanobodies with distinct epitopes, and analyze GPC1 protein expression in pancreatic cancer. We construct CARs with different extracellular spacers and test them in GPC1-positive cell and mouse models. We use droplet digital PCR and genomic sequencing methods to analyze persistent CAR T cells in mice.
Results: We isolate a camel nanobody D4 and a mouse monoclonal antibody HM2 recognizing the membrane-distal and membrane-proximal epitopes of GPC1, respectively, with similar high affinity. GPC1 protein was frequently detected in pancreatic tumor tissues and normal pancreas adjacent to tumors. Both D4 and HM2 CAR T cells with the hinge and transmembrane domain (TM) from CD8 regressed high GPC1-expressing xenograft tumors. Interestingly, D4 CAR containing a short IgG4 hinge spacer and CD28 TM outperformed the initial D4 CAR against low GPC1-expressing tumors in vitro and in vivo.
Conclusion: By optimizing spacer and TM designs, the activity of nanobody D4-based CAR T cell targeting a membrane-distal epitope of GPC1 is significantly enhanced against low GPC1-expressing tumors, suggesting it might improve the efficacy of GPC1-targeted CAR T cell therapy in pancreatic cancer.
Citation Format: Nan Li, Dan Li, Jiajia Pan, Mitchell Ho. Incorporation of an IgG4-derived spacer improves the activity of nanobody-based CAR T cells targeting a membrane-distal epitope of glypican 1 in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1541.
Abstract 1567: IL-15 and anti-PD-1 augment the abscopal efficacy of agonistic intratumoral anti-CD40 in the TRAMP-C2 murine tumor model
Authors: Chen Wei 
Published: July 2021

Abstract
IL-15 promotes activation and maintenance of natural killer (NK) and CD8+ T-effector memory (TEM) cells making it a potential immunotherapeutic agent for the treatment of cancer. However, high doses of γc cytokines lead to the paralysis/depression of naïve CD4 but not CD8 T-cells that is mediated through transient expression of suppressor of cytokine signaling 3 (SOCS3). Thus, the out-of-normal order addition of γc cytokines is associated with generation of “helpless” tumor antigen nonspecific CD8 T cells. The role of CD4 helper T cells can be alternatively mediated by CD40 signaling through the addition of agonistic anti-CD40 antibodies. However, parenteral administration of an agonistic anti-CD40 antibody is associated with unacceptable toxicity that can be avoided by intratumoral administration. Intratumoral immunotherapy that aims at generating a potent low toxic priming of antitumor immunity uses the tumor as its own vaccine. We investigated the combination of IL-15 with an intratumoral anti-CD40 monoclonal antibody using a dosing schedule based on our previous study in the TRAMP-C2 murine prostate cancer model. Here we demonstrated that given intratumorally anti-CD40 had abscopal efficacy, and that the combination of IL-15 with the intratumoral anti-CD40 showed an augmented immune response with an increase in the number of tumor specific tetramer positive CD8+ T-cells. Furthermore, anti-PD-1 antibody was additive to the anti-CD40 IL-15 combination. These studies support the initiation of a clinical trial in patients with cancer involving IL-15 in association with intratumoral optimized anti-CD40.
Citation Format: Wei Chen. IL-15 and anti-PD-1 augment the abscopal efficacy of agonistic intratumoral anti-CD40 in the TRAMP-C2 murine tumor model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1567.
Abstract 1582: T-SIGn cancer gene therapy and anti-EGFR CAR-T cells synergize in combination therapy to clear A549 lung tumor xenografts and lung metastases in NSG mice
Authors: Sonzogni Olmo , Zak Daniel , West Katy , Lear Rochelle , Muntzer Alice , Champion Brian R. , Rottman James B. 
Published: July 2021

Abstract
Chimeric antigen receptor (CAR) T cell therapy is an effective treatment for hematologic malignancies but has demonstrated limited efficacy in solid tumors. This is largely attributed to the immunosuppressive tumor microenvironment (TME) that impairs the ability of CAR-T cells to infiltrate, become activated, and kill tumor cells. Virotherapy is another emerging cancer treatment that has so far shown only limited clinical efficacy as a monotherapy for solid tumors. Importantly, in addition to their ability to directly kill tumor cells, viral vectors can also be leveraged to deliver transgenes to “reprogram” the TME from an immunosuppressive to a pro-inflammatory environment. We hypothesized that IV-deliverable T-SIGn cancer gene therapy vectors based on the oncolytic adenovirus enadenotucirev, which carry a transgene cassette encoding human immunomodulatory molecules to aid recruitment and activation of T-cells, could enhance the anti-tumor activity of human anti-EGFR CAR T cells in vivo. To test this hypothesis, NSG mice implanted subcutaneously with human lung cancer A549 xenografts, were treated intravenously with the T-SIGn virus followed by treatment with human anti-EGFR CAR-T cells. This treatment regimen demonstrated clearance of the xenograft and pulmonary metastases, whereas either therapy alone showed either no efficacy or delayed disease progression. When xenograft transcript analysis was performed, robust expression of the virus-encoded transgenes, as well as an upregulation of transcripts involved in type I IFN responses (e.g. IRF1, SOCS1), antigen presentation (e.g. HLA.DRA, TAP1), T cell activation (IFNγ, GrB), and inflammation (e.g. CXCL9, TNFSF10) was measured in the xenografts of animals treated with combination therapy, indicating a reprogramming of the TME to more effectively recruit and/or enhance T-cell responses. In addition, the combination treatment also dramatically reduced the number of A549 tumor cell micrometastases detectable in the lungs. Since both agents were delivered systemically, this observation may reflect direct therapeutic activity at the metastatic sites. Taken together, these results indicate that combination therapy with a T-SIGn vector and CAR T cells holds great potential to be efficacious in humans with solid tumors.
Citation Format: Olmo Sonzogni, Daniel Zak, Katy West, Rochelle Lear, Alice Muntzer, Brian R. Champion, James B. Rottman. T-SIGn cancer gene therapy and anti-EGFR CAR-T cells synergize in combination therapy to clear A549 lung tumor xenografts and lung metastases in NSG mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1582.
Abstract 1584: Efficacy and pharmacodynamic effect of anti-CD73/PD-L1 monoclonal antibodies in combination with chemotherapy: Observations from mouse tumor models
Authors: Eyles Jim , Watkins Amanda , Ilieva Kristina , Mullins Stef , Anderton Jude , Galvani Elena , Garcon Fabien , Ryan Kelli , Kaistha Brajesh P. , Dannhorn Andreas , Ling Stephanie , Slidel Tim , Kar Gozde , Schuller Alwin , Cooper Zachary A. , Sachsenmeier Kris , Luheshi Nadia , Kumar Rakesh , Wilkinson Robert W. 
Published: July 2021

Abstract
Intratumoral adenosine is a key immunosuppressive factor linked to poor prognosis and reduced efficacy of T cell checkpoint inhibitors. CD73 is an ectoenzyme and key node in the catabolic pathway responsible for sequential hydrolysis of extracellular ATP to adenosine. ATP is released from necrotic and damaged tumor cells; a phenomenon enhanced as consequence of cytotoxic chemotherapy or radiotherapy. A CD73 inhibiting human monoclonal IgG1-TM antibody, Oleclumab, is currently in phase 2 clinical development for treatment of patients with various solid tumors. The combination of CD73 inhibition with chemotherapy and T cell checkpoint inhibition was tested using two murine cancer models, CT26 (colorectal) or MCA205 (fibrosarcoma) implanted subcutaneously in BALB/c mice or C57BL/6 mice, respectively. Tumor bearing mice were treated with combinations of oxaliplatin and 5-fluorouracil and murine surrogate monoclonal antibodies for Oleclumab and Durvalumab (anti-PD-L1). CT26 implanted mice were also treated with the murine surrogate antibodies in the presence and absence of Docetaxel. In an attempt to define contribution of components, comparator groups received monotherapies and other iterations of the combination. Treatment with anti-CD73 and anti-PD-L1 antibodies, concomitantly with chemotherapy, resulted in improved tumor growth inhibition, plus increased proportions of complete tumor regression (P&lt;0.05). FACS analysis of CT26 tumors highlighted elevated frequencies of intratumoral IFN-gamma secreting T and NK cells in the chemotherapy plus double IO combination group (P&lt;0.05). Consistent with this, selective depletion of CD8 T cells significantly diminished tumor control and long term survival (P&lt;0.05). RNAseq and Mass spectrometry based imaging techniques were utilized as tools to explore biomarker changes and mechanism.
Citation Format: Jim Eyles, Amanda Watkins, Kristina Ilieva, Stef Mullins, Jude Anderton, Elena Galvani, Fabien Garcon, Kelli Ryan, Brajesh P. Kaistha, Andreas Dannhorn, Stephanie Ling, Tim Slidel, Gozde Kar, Alwin Schuller, Zachary A. Cooper, Kris Sachsenmeier, Nadia Luheshi, Rakesh Kumar, Robert W. Wilkinson. Efficacy and pharmacodynamic effect of anti-CD73/PD-L1 monoclonal antibodies in combination with chemotherapy: Observations from mouse tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1584.
Abstract 1604: Anticancer nanocage platforms for combined immunotherapy designed to harness immune checkpoints and deliver anticancer drugs
Authors: Kim Soyoun , Kim Minseong 
Published: July 2021

Abstract
The interaction of programmed cell death 1 ligand 1 (PD-L1) with its receptor, programmed cell death 1 (PD-1), inhibits T-cell responses. Monoclonal antibodies that block this interaction have been shown effective as immunotherapy. However, only a subset of cancers exhibits a durable response to PD-1/PD-L1 blockade. Moreover, antibody-based immune checkpoint blockade is costly and is occasionally accompanied by systemic side effects. To overcome these limitations of antibody-based immune checkpoint blockade, an immune checkpoint-blocking ferritin nanocage displaying 24 PD-L1 binding peptides (PD-L1pep1) on its surface was designed and constructed. These ferritin nanocages displaying PD-L1pep1 (PpNF) specifically bind to PD-L1 expressed on cancer cells or to purified PD-L1 with a ~30 nM binding affinity. The addition of PpNF to cocultures of T cells and cancer cells inhibited PD-1/PD-L1 interactions and restored T-cell activities. In a mouse model of syngeneic colon cancer, PpNF specifically targeted tumors and showed antitumor activity. Moreover, PpNF nanocages encapsulating the chemotherapeutic drug doxorubicin had more potent antitumor activity than a monoclonal antibody against PD-L1. These results demonstrate that ferritin nanocages displaying surface PD-L1pep1 can be efficiently applied for immunotherapy, especially when encapsulating small chemotherapeutic drugs. These nanocages may have promise as an immunotherapeutic nanomedicine against various solid tumors.
Citation Format: Soyoun Kim, Minseong Kim. Anticancer nanocage platforms for combined immunotherapy designed to harness immune checkpoints and deliver anticancer drugs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1604.
Abstract 1610: Local delivery of anti CTLA4 mediates cDC1 dependent eradication of HNSCC with limited IRAEs in a preclinical model of oral squamous cell carcinoma
Authors: Gilardi Mara , Wang Zhiyong , Wu Victoria H. , Lopez-Ramirez Miguel Angel , Soto-Alvarez Fernando , Saddawi-Konefka Robert , Steffen Dana , Proietto Marco , Mikulski Zbigniew , Miki Haruka , Narayanan Jayanth Shankara , Molinolo Alfredo , Wang Joseph , Gutkind J. Silvio 
Published: July 2021

Abstract
Head and neck squamous cell carcinoma (HNSCC) ranks 6th in cancer incidence worldwide and has a five-year survival rate of only 63%. Despite advances in curative-intent therapies over the past three decades, rates of recurrence exceed 50% and long-term toxicities remain unacceptably morbid. Immunotherapies - principally immune checkpoint inhibitors (ICI) such as αPD-1 and αCTLA-41 antibodies which restore endogenous antitumor T cell immunity - offer the greatest promise for achieving durable response in HNSCC. However, the clinical application of ICI has been limited by immune-related adverse events (irAEs), which is a consequence of compromised peripheral immune tolerance after ICI therapy. Although irAEs are often reversible they can become severe, at best prompting premature termination of therapy or at worst becoming life-threatening. To address the off-target irAEs inherent to systemic ICI therapy, we developed a novel, local delivery strategy based upon an array of soluble microneedles (MN). Leveraging our recently reported syngeneic, tobacco-signature murine HNSCC model, we characterized the αCTLA-41 anti-tumor response as both CD8 T cell- and conventional dendritic cell type 1-dependent. When comparing αCTLA-4 therapy delivered in the traditional systemic format or with our local-MN delivery system, we found that while both routes of delivery led to &gt;90% tumor responses, local-MN delivery achieved responses with lower total dosing while also limiting distribution of αCTLA-41 antibody from areas distal to draining lymphatic basins. Employing the previously described Foxp3-GFP-DTR GEMM developed for interrogation of murine irAEs, we found that local-MN protected animals from irAEs observed with systemic therapy. Taken together, our findings support the exploration of the microneedle array as a viable delivery strategy for ICI treatment in HNSCC.
Citation Format: Mara Gilardi, Zhiyong Wang, Victoria H. Wu, Miguel Angel Lopez-Ramirez, Fernando Soto-Alvarez, Robert Saddawi-Konefka, Dana Steffen, Marco Proietto, Zbigniew Mikulski, Haruka Miki, Jayanth Shankara Narayanan, Alfredo Molinolo, Joseph Wang, J. Silvio Gutkind. Local delivery of anti CTLA4 mediates cDC1 dependent eradication of HNSCC with limited IRAEs in a preclinical model of oral squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1610.