Activation Of Dendritic Cells Research Articles

NIR Absorbing Organic Chromophores Combination with NSAIDs for Remodeling of the Inflammatory Microenvironment to Amplify Tumor Ferroptosis-Photothermal Synergistic Therapy.

Photothermal therapy has emerged as a promising approach for cancer treatment, which can cause ferroptosis to enhance immunotherapeutic efficacy. However, excessively generated immunogenicity will induce serious inflammatory response syndrome, resulting in a discounted therapeutic effect. Herein, a kind of NIR absorption small organic chromophore nanoparticles (TTHM NPs) with high photothermal conversion efficiency (68.33%) is developed, which can induce mitochondria dysfunction, generate mitochondrial superoxide, and following ferroptosis. TTHM NPs-based photothermal therapy is combined with Sulfasalazine (SUZ), a kind of nonsteroidal anti-inflammatory drugs, to weaken inflammation and promote ferroptosis through suppressing glutamate/cystine (Glu/Cys) antiporter system Xc- (xCT). Additionally, the combination of SUZ with PTT can induce immunogenic cell death (ICD), followed by promoting the maturation of DCs and the attraction of CD8+ T cell, which will secrete IFN-γ and trigger self-amplified ferroptosis via inhibiting xCT and simulating Acyl-CoA synthetase long-chain family member 4 (ACSL4). Moreover, the in vivo results demonstrate that this combination therapy can suppress the expression of inflammatory factors, enhance dendritic cell activation, facilitate T-cell infiltration, and realize effective thermal elimination of primary tumors and distant tumors. In general, this work provides an excellent example of combined medication and stimulates new thinking about onco-therapy and inflammatory response.

Irradiated microparticles suppress prostate cancer by tumor microenvironment reprogramming and ferroptosis

Immunogenic cell death (ICD) plays a crucial role in triggering the antitumor immune response in the tumor microenvironment (TME). Recently, considerable attention has been dedicated to ferroptosis, a type of ICD that is induced by intracellular iron and has been demonstrated to change the immune desert status of the TME. However, among cancers that are characterized by an immune desert, such as prostate cancer, strategies for inducing high levels of ferroptosis remain limited. Radiated tumor cell-derived microparticles (RMPs) are radiotherapy mimetics that have been shown to activate the cGAS-STING pathway, induce tumor cell ferroptosis, and inhibit M2 macrophage polarization. RMPs can also act as carriers of agents with biocompatibility. In the present study, we designed a therapeutic system wherein the ferroptosis inducer RSL-3 was loaded into RMPs, which were tested in in vitro and in vivo prostate carcinoma models established using RM-1 cells. The apoptosis inducer CT20 peptide (CT20p) was also added to the RMPs to aggravate ferroptosis. Our results showed that RSL-3- and CT20p-loaded RMPs (RC@RMPs) led to ferroptosis and apoptosis of RM-1 cells. Moreover, CT20p had a synergistic effect on ferroptosis by promoting reactive oxygen species (ROS) production, lipid hydroperoxide production, and mitochondrial instability. RC@RMPs elevated dendritic cell (DC) expression of MHCII, CD80, and CD86 and facilitated M1 macrophage polarization. In a subcutaneously transplanted RM-1 tumor model in mice, RC@RMPs inhibited tumor growth and prolonged survival time via DC activation, macrophage reprogramming, enhancement of CD8+ T cell infiltration, and proinflammatory cytokine production in the tumor. Moreover, combination treatment with anti-PD-1 improved RM-1 tumor inhibition. This study provides a strategy for the synergistic enhancement of ferroptosis for prostate cancer immunotherapies.Graphical

Genetically Edited Cascade Nanozymes for Cancer Immunotherapy.

Immune checkpoint blockade (ICB) has brought tremendous clinical progress, but its therapeutic outcome can be limited due to insufficient activation of dendritic cells (DCs) and insufficient infiltration of cytotoxic T lymphocytes (CTLs). Evoking immunogenic cell death (ICD) is one promising strategy to promote DC maturation and elicit T-cell immunity, whereas low levels of ICD induction of solid tumors restrict durable antitumor efficacy. Herein, we report a genetically edited cell membrane-coated cascade nanozyme (gCM@MnAu) for enhanced cancer immunotherapy by inducing ICD and activating the stimulator of the interferon genes (STING) pathway. In the tumor microenvironment (TME), the gCM@MnAu initiates a cascade reaction and generates abundant cytotoxic hydroxyl (•OH), resulting in improved chemodynamic therapy (CDT) and boosted ICD activation. In addition, released Mn2+ during the cascade reaction activates the STING pathway and further promotes the DC maturation. More importantly, activated immunogenicity in the TME significantly improves gCM-mediated PD-1/PD-L1 checkpoint blockade therapy by eliciting systemic antitumor responses. In breast cancer subcutaneous and lung metastasis models, the gCM@MnAu showed synergistically enhanced therapeutic effects and significantly prolonged the survival of mice. This work develops a genetically edited nanozyme-based therapeutic strategy to improve DC-mediated cross-priming of T cells against poorly immunogenic solid tumors.

Engineered Bacteriophage-Based In Situ Vaccine Remodels a Tumor Microenvironment and Elicits Potent Antitumor Immunity.

In situ vaccines (ISVs) utilize the localized delivery of chemotherapeutic agents or radiotherapy to stimulate the release of endogenous antigens from tumors, thereby eliciting systemic and persistent immune activation. Recently, a bioinspired ISV strategy has attracted tremendous attention due to its features such as an immune adjuvant effect and genetic plasticity. M13 bacteriophages are natural nanomaterials with intrinsic immunogenicity, genetic flexibility, and cost-effectiveness for large-scale production, demonstrating the potential for application in cancer vaccines. In this study, we propose an ISV based on the engineered M13 bacteriophage targeting CD40 (M13CD40) for dendritic cell (DC)-targeted immune stimulation, named H-GM-M13CD40. We induce immunogenic cell death and release tumor antigens through local delivery of (S)-10-hydroxycamptothecin (HCPT), followed by intratumoral injection of granulocyte-macrophage colony stimulating factor (GM-CSF) and M13CD40 to enhance DC recruitment and activation. We demonstrate that this ISV strategy can result in significant accumulation and activation of DCs at the tumor site, reversing the immunosuppressive tumor microenvironment. In addition, H-GM-M13CD40 can synergize with the PD-1 blockade and induce abscopal effects in cold tumor models. Overall, our study verifies the immunogenicity of the engineered M13CD40 bacteriophage and provides a proof of concept that the engineered M13CD40 phage can function as an adjuvant for ISVs.

Mast cell-derived interleukin-4 mediates activation of dendritic cell during toll-like receptor 2-mediated inflammation

IntroductionDuring an innate inflammation, immune cells form distinct pro- and anti-inflammatory regions around pathogen-containing core-regions. Mast cells are localized in an anti-inflammatory microenvironment during the resolution of an innate inflammation, suggesting antiinflammatory roles of these cells.MethodsHigh-content imaging was used to investigated mast cell-dependent changes in the regional distribution of immune cells during an inflammation, induced by the toll-like receptor (TLR)-2 agonist zymosan.ResultsThe distance between the zymosan-containing core-region and the anti-inflammatory region, described by M2-like macrophages, increased in mast cell-deficient mice. Absence of mast cells abolished dendritic cell (DC) activation, as determined by CD86-expression and localized the DCs in greater distance to zymosan particles. The CD86- DCs had a higher expression of the pro-inflammatory interleukins (IL)-1β and IL-12/23p40 as compared to activated CD86+ DCs. IL-4 administration restored CD86 expression, cytokine expression profile and localization of the DCs in mast cell-deficient mice. The IL-4 effects were mast cell-specific, since IL-4 reduction by eosinophil depletion did not affect activation of DCs.DiscussionWe found that mast cells induce DC activation selectively at the site of inflammation and thereby determine their localization within the inflammation. Overall, mast cells have antiinflammatory functions in this inflammation model and limit the size of the pro-inflammatory region surrounding the zymosan-containing core region.

The gut lactic acid bacteria metabolite, 10-oxo-cis-6,trans-11-octadecadienoic acid, suppresses inflammatory bowel disease in mice by modulating the NRF2 pathway and GPCR-signaling

Various gut bacteria, including Lactobacillus plantarum, possess several enzymes that produce hydroxy fatty acids (FAs), oxo FAs, conjugated FAs, and partially saturated FAs from polyunsaturated FAs as secondary metabolites. Among these derivatives, we identified 10-oxo-cis-6,trans-11-octadecadienoic acid (γKetoC), a γ-linolenic acid (GLA)-derived enon FA, as the most effective immunomodulator, which inhibited the antigen-induced immunoactivation and LPS-induced production of inflammatory cytokines. The treatment with γKetoC significantly suppressed proliferation of CD4+ T cells, LPS-induced activation of bone marrow-derived dendritic cells (BMDCs), and LPS-induced IL-6 release from peritoneal cells, splenocytes, and CD11c+ cells isolated from the spleen. γKetoC also inhibited the release of inflammatory cytokines from BMDCs stimulated with poly-I:C, R-848, or CpG. Further in vitro experiments using an agonist of GPR40/120 suggested the involvement of these GPCRs in the effects of γKetoC on DCs. We also found that γKetoC stimulated the NRF2 pathway in DCs, and the suppressive effects of γKetoC and agonist of GPR40/120 on the release of IL-6 and IL-12 were reduced in Nrf2-/- BMDCs. We evaluated the role of NRF2 in the anti-inflammatory effects of γKetoC in a dextran sodium sulfate-induced colitis model. The oral administration of γKetoC significantly reduced body weight loss, improved stool scores, and attenuated atrophy of the colon, in wild-type C57BL/6 and Nrf2+/- mice with colitis. In contrast, the pathology of colitis was deteriorated in Nrf2-/- mice even with the administration of γKetoC. Collectively, the present results demonstrated the involvement of the NRF2 pathway and GPCRs in γKetoC-mediated anti-inflammatory responses.

Weighted Gene Co-expression Network Analysis and Machine Learning Validation for Identifying Major Genes Related to Sjogren's Syndrome.

Sjogren's syndrome (SS) is an autoimmune disorder characterized by dry mouth and dry eyes. Its pathogenic mechanism is currently unclear. This study aims to integrate weighted gene co-expression network analysis (WGCNA) and machine learning to identify key genes associated with SS. We downloaded 3 publicly available datasets from the GEO database comprising the gene expression data of 231 SS and 78 control cases, including GSE84844, GSE48378 and GSE51092, and carried out WGCNA to elucidate differences in the abundant genes. Candidate biomarkers for SS were then identified using a LASSO regression model. Totally 6 machine-learning models were subsequently utilized for validating the biological significance of major genes according to their expression. Finally, immune cell infiltration of the SS tissue was assessed using the CIBERSORT algorithm. A weighted gene co-expression network was built to divide genes into 10 modules. Among them, blue and red modules were most closely associated with SS, and showed significant enrichment in type I interferon signaling, cellular response to type I interferon and response to virus, etc. Combined machine learning identified 5 hub genes, including OAS1, EIF2AK2, IFITM3, TOP2A and STAT1. Immune cell infiltration analysis showed that SS was associated with CD8+ T cell, CD4+ T cell, gamma delta T cell, NK cell and dendritic cell activation. WGCNA was combined with machine learning to uncover genes that may be involved in SS pathogenesis, which can be utilized for developing SS biomarkers and appropriate therapeutic targets.

Core-shell nanomedicine based on multifunctional tetrahedral DNA nanostructures for synergistic enhancement of tumor chemodynamic/chemo-immunotherapy

Immune checkpoint blockade therapy has made great strides in cancer treatment, but conventional immune checkpoint blockade antibodies often lead to overactivation of the immune system and severe immune-related adverse effects. Herein, we report the design of a nanomedicine (denoted as CPD@M−TDN) based on multifunctional tetrahedral DNA nanostructures (M−TDN). In this system, a bimetallic metal–organic framework (Cu/ZIF-8) is synthesized as the core; doxorubicin-loaded polydopamine acts as a shell to reduce the immunogenicity of the nanomaterials in peripheral blood. Finally, the CpG oligodeoxynucleotides and PD-L1 aptamer-based M−TDN are coupled to the core–shell structure nanomedicine through the biotin-avidin-system. Under the acidic tumor microenvironment, the decomposition of Cu/ZIF-8 and the release of copper ions and doxorubicin can lead to immunogenic death of tumor cells through chemodynamic/chemotherapy. Furthermore, the M−TDN has the dual effects of weakening the immunosuppressive microenvironment with PD-L1 aptamer and promoting dendritic cell activation with the immunostimulant CpG. Overall, the developed CPD@M−TDN can effectively enhance the response rate to immunotherapy and has excellent potential in the field of integrated tumor treatment.

Multicomponent Pathogen-Mimicking Nanoparticles Induce Intestinal Immune Responses against Paratuberculosis.

Given the worldwide problem posed by enteric pathogens, the discovery of safe and efficient intestinal adjuvants combined with novel antigen delivery techniques is essential to the design of mucosal vaccines. In this work, we designed poly (lactic-co-glycolic acid) (PLGA)-based nanoparticles (NPs) to codeliver all-trans retinoic acid (atRA), novel antigens, and CpG. To address the insolubility of the intestinal adjuvant atRA, we utilized PLGA to encapsulate atRA and form a "nanocapsid" with polydopamine. By leveraging polydopamine, we adsorbed the water-soluble antigens and the TLR9 agonist CpG onto the NPs' surface, resulting in the pathogen-mimicking PLPCa NPs. In this study, the novel fusion protein (HBf), consisting of the Mycobacterium avium subspecies paratuberculosis antigens HBHA, Ag85B, and Bfra, was coloaded onto the NPs. In vitro, PLPCa NPs were shown to promote the activation and maturation of bone marrow-derived dendritic cells. Additionally, we found that PLPCa NPs created an immune-rich microenvironment at the injection site following intramuscular administration. From the results, the PLPCa NPs induced strong IgA levels in the gut in addition to enhancing powerful systemic immune responses. Consequently, significant declines in the bacterial burden and inflammatory score were noted in PLPCa NPs-treated mice. In summary, PLPCa can serve as a novel and safe vaccine delivery platform against gut pathogens, such as paratuberculosis, capable of activating both systemic and intestinal immunity.

Human NLRC4 promotes cancer survival and is associated to type-I interferon signaling and immune infiltration.

The immune system can control cancer progression. However, even though some innate immune sensors of cellular stress are expressed intrinsically in epithelial cells, their potential role in cancer aggressiveness and subsequent overall survival in humans is mainly unknown. Here, we show that NLR family CARD Domain Containing 4 (NLRC4) is downregulated in epithelial tumor cells of colorectal cancer (CRC) patients by using spatial tissue imaging. Strikingly, only the loss of tumor NLRC4 but not stromal is associated with poor immune infiltration (mainly dendritic and CD4+/CD8+ T cells) and accurately predicts progression to metastatic Stage IV and decrease of overall survival. By combining multi-omics approaches, we show that restoring NLRC4 expression in human colorectal cancer cells triggers a broad inflammasome-independent immune reprogramming consisting of Type-I IFN signaling genes and the release of chemokines and myeloid growth factors involved in the tumor infiltration and activation of dendritic cells (DCs) and T cells. Consistently, such reprogramming in cancer cells is sufficient to directly mature human DCs towards a Th1 antitumor immune response through IL-12 production in vitro. In multiple human carcinomas (colorectal, lung, and skin), we confirmed that NLRC4 expression in patient tumors is strongly associated with Type-I IFN genes, immune infiltrates and high microsatellite instability. Thus, we shed light on the epithelial innate immune sensor NLRC4 as a novel therapeutic target to promote an efficient antitumor immune response against the aggressiveness of various carcinomas.

Rhein‐based Pickering emulsion for hepatocellular carcinoma: Shaping the metabolic signaling and immunoactivation in transarterial chemoembolization

AbstractThe efficacy of transarterial chemoembolization (TACE) has been limited by insufficient embolization and a high incidence of tumor recurrence. Herein, we identified that aberrant metabolic reprogramming and immunosuppression contribute to TACE refractoriness and Rhein, as a potential glycolytic metabolism inhibitor and immunoactivation inducer, was optimized to sensitize tumors to TACE therapy. To achieve efficient embolization, we developed an oil‐in‐water lipiodol embolic emulsion by stabilizing the self‐assembled Rhein nanogel. The assembled Rhein exhibited a nanofiber network, and its integration enhanced the mechanical stability and viscoelasticity of the lipiodol embolic agent. With the synergistic advantages of solid and liquid embolic agents, this carrier‐free Pickering emulsion exhibits efficient embolization and sustained drug release in models of unilateral renal artery embolization, rabbit ear tumor embolization, rabbit orthotopic liver cancer, and rat orthotopic liver cancer. Compared to conventional three‐way catheter mixing methods, multimodal imaging corroborates a marked enhancement in local drug retention and tumor suppression. Importantly, the incorporation of Rhein‐mediated synergistic immunoembolization in this strategy achieved efficient embolization while robustly activating anti‐tumor immune responses, including inducing immunogenic cell death, dendritic cell activation, and major histocompatibility complex class I presentation to CD8+ T cells for tumor killing. Together, these findings reveal a novel strategy for the application of self‐assembled Rhein nanofiber‐stabilized lipiodol emulsion to control metabolic signaling and immunoactivation in TACE.

Benchmarking of BMDC assay and related QSAR study for identifying sensitizing chemicals

The Bone-Marrow derived Dendritic Cell (BMDC) test is a promising assay for identifying sensitizing chemicals based on the 3Rs (Replace, Reduce, Refine) principle.This study expanded the BMDC benchmarking to various in vitro, in chemico, and in silico assays targeting different key events (KE) in the skin sensitization pathway, using common substances datasets. Additionally, a Quantitative Structure-Activity Relationship (QSAR) model was developed to predict the BMDC test outcomes for sensitizing or non-sensitizing chemicals. The modeling workflow involved ISIDA (In Silico Design and Data Analysis) molecular fragment descriptors and the SVM (Support Vector Machine) machine-learning method.The BMDC model's performance was at least comparable to that of all ECVAM-validated models regardless of the KE considered. Compared with other tests targeting KE3, related to dendritic cell activation, BMDC assay was shown to have higher balanced accuracy and sensitivity concerning both the Local Lymph Node Assay (LLNA) and human labels, providing additional evidence for its reliability. The consensus QSAR model exhibits promising results, correlating well with observed sensitization potential. Integrated into a publicly available web service, the BMDC-based QSAR model may serve as a cost-effective and rapid alternative to lab experiments, providing preliminary screening for sensitization potential, compound prioritization, optimization and risk assessment.

The Impact of Prevotella on Neurobiology in Aging: Deciphering Dendritic Cell Activity and Inflammatory Dynamics.

Prevotella species, notably Prevotella copri, significantly populate the human gut. In particular, P. copri is prevalent among non-Western populations with diets high in fiber. These species show complex relationships with diverse health aspects, associating with beneficial outcomes, including reduced visceral fat and improved glucose tolerance. Studies implicate various Prevotella species in specific diseases. Prevotella nigrescens and Porphyromonas gingivalis were linked to periodontal disease, promoting immune responses and influencing T helper type 17 (Th17) cells. Prevotella bivia was associated with bacterial vaginosis and a specific increase in activated cells in the vaginal mucosa. In contrast, they have shown substantial potential for inducing connective tissue degradation and alveolar bone resorption. Prevotella's role in neuroinflammatory disorders and autoinflammatory conditions such as Alzheimer's disease and Parkinson's disease has also been noted. The complex relationship between Prevotella and age-related conditions further extends to neurobiological changes in aging, with varying associations with Alzheimer's, Parkinson's, and other inflammatory conditions. Studies have also identified Prevotella to be implicated in cognitive decline in middle aged and the elderly. Future directions in this research area are anticipated to explore Prevotella-associated inflammatory mechanisms and therapeutic interventions. Investigating specific drug targets and immunomodulatory measures could lead to novel therapeutic strategies. Understanding how Prevotella-induced inflammation interacts with aging diseases would offer promising insights for treatments and interventions. This review urges ongoing research to discover therapeutic targets and mechanisms for moderating Prevotella-associated inflammation to further enhance our understanding and improve health outcomes.

Exploring dendritic cell subtypes in cancer immunotherapy: unraveling the role of mature regulatory dendritic cells

Dendritic cells (DCs) possess a specialized function in presenting antigens and play pivotal roles in both innate and adaptive immune responses. Their ability to cross-present antigens from tumor cells to naïve T cells is instrumental in generating specific T-cell-mediated antitumor responses, crucial for controlling tumor growth and preventing tumor cell dissemination. However, within a tumor immune microenvironment (TIME), the functions of DCs can be significantly compromised. This review focuses on the profile, function, and activation of DCs, leveraging recent studies that reveal insights into their phenotype acquisition, transcriptional state, and functional programs through single-cell RNA sequence (scRNA-seq) analysis. Additionally, the therapeutic potential of DC-mediated tumor antigen sensing in priming antitumor immunity is discussed.

The orientation of CpG conjugation on aluminum oxyhydroxide nanoparticles determines the immunostimulatory effects of combination adjuvants

In subunit vaccines, aluminum salts (Alum) are commonly used as adjuvants, but with limited cellular immune responses. To overcome this limitation, CpG oligodeoxynucleotides (ODNs) have been used in combination with Alum. However, current combined usage of Alum and CpG is limited to linear mixtures, and the underlying interaction mechanism between CpG and Alum is not well understood. Thus, we propose to chemically conjugate Alum nanoparticles and CpG (with 5′ or 3′ end exposed) to design combination adjuvants. Our study demonstrates that compared to the 3′-end exposure, the 5′-end exposure of CpG in combination adjuvants (Al-CpG-5′) enhances the activation of bone-marrow derived dendritic cells (BMDCs) and promotes Th1 and Th2 cytokine secretion. We used the SARS-CoV-2 receptor binding domain (RBD) and hepatitis B surface antigen (HBsAg) as model antigens to demonstrate that Al-CpG-5′ enhanced antigen-specific antibody production and upregulated cytotoxic T lymphocyte markers. Additionally, Al-CpG-5′ allows for coordinated adaptive immune responses even at lower doses of both CpG ODNs and HBsAg antigens, and enhances lymph node transport of antigens and activation of dendritic cells, promoting Tfh cell differentiation and B cell activation. Our novel Alum-CPG strategy points the way towards broadening the use of nanoadjuvants for both prophylactic and therapeutic vaccines.

3,3'-Diindolylmethane inhibits Th17 cell differentiation via impairing IRF-7-mediated plasmacytoid dendritic cell activation in imiquimod-induced psoriasis mice.

Psoriasis is a paradigmatic condition characterised by a heightened autoimmune response and chronic inflammation. However, the exact nature and the pathological causes behind it are still unknown. Growing evidence suggest dysregulated cytokine network as a result of over-activated T cells and plasmacytoid dendritic cells (pDCs) as the critical drivers in the development of psoriasis. In the present study, we aimed to investigate the therapeutic efficacy of 3,3'-diindolylmethane (DIM) on pDC activation and Th17 cell development in imiquimod (IMQ)-induced psoriasis mice. Our in vitro research investigated the IRF-7 signalling in pDCs that explained the reduced expression of the transcription factor IRF-7 responsible for pDC activation as a result of DIM treatment. Concurrently, DIM treatment decreased the release of Th17 cell polarising cytokines (IFN-α, IL-23, and IL-6) by pDCs which validated a reduction in differentiated pathogenic Th17 cell population and associated cytokine IL-17A in IMQ-induced psoriatic mice. Thus, our recent findings provide therapeutic evidence in targeting the early potential contributors for psoriasis treatment by preventing IRF-7-mediated pDC activation and Th17 cell development in IMQ-induced psoriasis mice.

Immunomodulation by juglone alleviates acute graft-versus-host disease without compromising the graft-versus-leukaemia activity in mice.

Acute graft-versus-host disease (GVHD) remains a major barrier to successful transplantation outcomes. Recent studies have shown that pharmacotherapy for GVHD should target both the innate and adaptive inflammatory immune responses. Juglone, a redox-active phytochemical found in walnuts, has shown potent anti-inflammatory effects in models of colitis and inflammatory bowel disease. However, its effects on T-cell-mediated immune responses remain largely unknown. Considering the overlapping mediators of inflammation in GVHD and the aforementioned conditions, we investigated the use of juglone as a prophylactic agent for GVHD. Immunomodulatory activity and mechanism of action of juglone were studied using murine splenic leukocytes in vitro. The GVHD prophylactic efficacy of orally administered juglone was evaluated using a murine model of allogeneic haematopoietic stem cell transplantation based on an MHC mismatch. Juglone exhibited immunomodulatory activity by (i) inhibiting the activation of dendritic cells and CD4+ T-cells, (ii) inhibiting cytokine secretion and lymphocyte proliferation, and (iii) inducing exhaustion of CD4+ T-cells, as shown by increased expression of CTLA-4 (CD152) and Fas (CD95). Oral administration of juglone significantly reduced mortality and morbidity associated with GVHD while maintaining graft-versus-leukaemia activity. This was accompanied by a decrease in the number of naïve CD4+ cells, and an increase in the number of CD4+ and CD8+ central memory T-cells. Juglone is a potent immunomodulator for GVHD prophylaxis. Our study is the first to provide a dosage framework for the oral administration of juglone that can be used for clinical development.

Abstract LB306: PD-L1-targeted radioimmunethrapeutics combined with oncolytic virus for treatment of pancreatic cancer

Abstract Pancreatic cancer is difficult to treat, and the first line treatment provide only modest survival benefits to patients due to its highly desmoplastic and immune-desert phenotype. To overcome these hurdles, PD-L1-targeted radioimmunotherapy (RIT) using lutetium-177-labelled atezolizumab (177Lu-aPD-L1) combined with an oncolytic virus, named HY-oAd, that co-expresses three therapeutic genes (interleukin-12, granulocyte-macrophage colony-stimulating factor and relaxin) was investigated. HY-oAd treatment was shown to elevate PD-L1 expression level and promoted degradation of extracellular matrix (ECM) of pancreatic tumors, resulting in increased aPD-L1 or 64Cu-aPD-L1 accumulation in tumor tissues. Moreover, HY-oAd in combination with either aPD-L1 or 177Lu-aPD-L1 elicited more potent antitumor effect against the pancreatic tumors than respective monotherapy in pancreatic tumor models. The potent antitumor effect of HY-oAd+aPD-L1 combination therapy can lead to superior intratumoral infiltration and activation of dendritic cells and CD4+ or CD8+ T cells over the respective monotherapy. Collectively, our findings demonstrate that HY-oAd can potentiate PD-L1-targeted RIT through PD-L1 upregulation and ECM degradation, thus resulting in synergistic antitumor efficacy and antitumor immune response. Citation Format: Arum Yoon, Chae-Ok Yun, Jin Su Kim. PD-L1-targeted radioimmunethrapeutics combined with oncolytic virus for treatment of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB306.

Abstract LB120: Stem cell-derived ACUA CAR-NKT allogeneic cell therapies harness orthogonal mechanisms of action for the treatment of solid tumors

Abstract Despite the remarkable success of chimeric antigen receptor T cell (CAR-T) therapies in treating hematological malignancies, their use in solid tumor indications has been met with distinct challenges. The immunosuppressive tumor microenvironment (TME) and tumor antigen heterogeneity are two significant factors that may adversely impact the efficacy of these ground-breaking therapies. Engineered natural killer T (NKT) cells harbor biological features distinct from CAR-T cell or CAR-NK cell therapies and thus represent a novel therapeutic approach to deploy “off the shelf” to patients. Appia Bio’s ACUA platform is capable of generating large quantities of highly pure CAR-NKT cells from cord blood CD34+ hematopoietic stem and progenitor cells (HSPCs) for clinical use. We have demonstrated that multiple distinct mechanisms of anti-tumor activity are operative in CAR-NKT cells, including CAR-mediated killing, NK receptor-mediated killing, adjuvant effects on antigen-specific T cells and immature dendritic cells, as well as the ability to deplete of pro-tumorigenic macrophages.When transduced with a CAR, ACUA-derived CAR-NKT cells show potent CAR-mediated tumor cell killing, similar to CAR-T cells. In contrast to conventional T cells, CAR-NKT cells also demonstrate potent CAR antigen-independent tumor cell killing, mediated partially through NKG2D and DNAM-1 activating NK receptors. CAR-NKT cells, but not conventional CAR-T cells, enhanced the function of NY-ESO specific T cells in controlling multiple rounds of tumor rechallenge, through the secretion of soluble components. In regard to other adjuvant effects which may provide additional benefit in vivo, ACUA-derived NKT cells enhanced the activation of peripheral blood monocyte-derived dendritic cells, which can regulate beneficial Th1 type immune responses. To explore how ACUA-derived NKT cells could reshape the TME, we generated immunosuppressive M2-polarized macrophages and observed that ACUA-derived NKT cells can either kill or reprogram these cells to a pro-inflammatory phenotype following co-culture. Notably, these immune cell adjuvant mechanisms are specific to ACUA-derived NKT cells and are not observed with conventional CAR-T cells. In summary, these mechanistic studies underscore the advantages of ACUA-derived NKT cells over conventional CAR-T cells and highlight their potential as a promising differentiated allogeneic therapy for the treatment of solid tumors. Citation Format: Xi Wang, Andrew J. Hou, Michael A. Christopher, Yannick Bulliard, Jason S. Damiano. Stem cell-derived ACUA CAR-NKT allogeneic cell therapies harness orthogonal mechanisms of action for the treatment of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB120.

Abstract CT016: Immunomodulation of the tumor microenvironment of pancreatic ductal adenocarcinoma with histone deacetylase inhibition: Results of a phase 2 clinical trial of entinostat in combination with nivolumab

Abstract Background The tumor microenvironment (TME) of pancreatic ductal adenocarcinoma (PDA) is characterized by a paucity of cytotoxic tumor-infiltrating lymphocytes, an abundance of immune-suppressive cell populations, and a general resistance to immune checkpoint inhibitor (ICI) therapy. In preclinical models of PDA, the HDAC inhibitor entinostat modulated the transcriptional programming of myeloid cells, reducing their capacity for immunosuppression and sensitizing tumors to ICI therapy. Methods We conducted a single-center, open-label, Simon two-stage, phase II study of entinostat in combination with the PD1 inhibitor nivolumab in patients with advanced PDA. Patients received oral entinostat 5 mg once a week. After a 14-day lead-in with entinostat monotherapy, patients concurrently receive entinostat 5 mg orally once a week plus nivolumab 240 mg intravenously every 2 weeks. After 4 months, therapy was continued with entinostat 5 mg weekly plus nivolumab at a dose of 480 mg fixed dose every 4 weeks until the time of progression or unacceptable toxicities. The primary endpoint was the objective response rate by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Peripheral immune profiles at baseline and on treatment were assessed by high-dimensional mass cytometry by time of flight (CyTOF) and by Luminex of chemokines in the plasma, and changes in the TME were performed on paired baseline and on treatment biopsies by multiplexed immunohistochemistry (mIHC), image cytometry-based quantification, and bulk RNA-seq analysis. Results From November 2017 to November 2020, 27 evaluable patients were enrolled. Three patients had a partial response (PR) by RECIST v1.1 criteria (objective response rate (ORR)) of 11%, 95% CI, 0.024-0.292), with a median duration of response of 10.2 months. Grade ≥3 treatment-related adverse events (TRAEs) were observed in 19 (63%) patients. The most common grade ≥3 TRAEs were decreased lymphocyte count, anemia hypoalbuminemia, and hyponatremia. Dendritic cell (DC) activation, maturation, migration, antigen processing, and presentation were increased in the periphery after entinostat treatment, consistent with HDAC inhibitor mediated myeloid reprogramming. Gene expression analysis of paired baseline and on treatment tumors demonstrated an enrichment in inflammatory response signaling pathways with combination treatment. Conclusions Entinostat and nivolumab demonstrated durable radiological responses in a subset of patients with PDA. Paired tissue and peripheral analysis showed immunomodulation of myeloid cell populations, consistent with the preclinical hypothesis supporting the trial. This study creates a roadmap for this strategy with future combinatorial therapeutic approaches to enhance the clinical benefit in PDA patients further. Citation Format: Marina Baretti, Ludmila Danilova, Jennifer N. Durham, Courtney B. Betts, Leslie Cope, Dimitrios N. Sidiropoulos, Joseph A. Tandurella, Soren Charmsaz, Nicole Gross, Alexei Hernandez, Won J. HO, Chris Thoburn, Rosalind Walker, James Leatherman Leatherman, Sarah Mitchell, Brian Christmas, Daria A. Gaykalova, Srinivasan Yegnasubramanian, Elana J. Fertig, Lisa M. Coussens, Mark Yarchoan, Elizabeth Jaffee, Nilofer S. Azad. Immunomodulation of the tumor microenvironment of pancreatic ductal adenocarcinoma with histone deacetylase inhibition: Results of a phase 2 clinical trial of entinostat in combination with nivolumab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT016.