Tool For Immunotherapy Research Articles

Conditional Activation of c-MYC in Distinct Catecholaminergic Cells Drives Development of Neuroblastoma or Somatostatinoma.

c-MYC is an important driver of high-risk neuroblastoma. A lack of c-MYC-driven genetically engineered mouse models (GEMM) has hampered the ability to better understand mechanisms of neuroblastoma oncogenesis and to develop effective therapies. Here, we showed that conditional c-MYC induction via Cre recombinase driven by a tyrosine hydroxylase (Th) promoter led to a preponderance of PDX1+ somatostatinoma, a type of pancreatic neuroendocrine tumor (PNET). However, c-MYC activation via an improved Cre recombinase driven by a dopamine β-hydroxylase (Dbh) promoter resulted in neuroblastoma development. The c-MYC murine neuroblastoma tumors recapitulated the pathologic and genetic features of human neuroblastoma and responded to anti-GD2 immunotherapy and DFMO, an FDA-approved inhibitor targeting the MYC transcriptional target ODC1. Thus, c-MYC overexpression results in different but related tumor types depending on the targeted cell. The GEMMs represent valuable tools for testing immunotherapies and targeted therapies for these diseases.

Better, Faster, Stronger: Accelerating mRNA-Based Immunotherapies With Nanocarriers.

Messenger ribonucleic acid (mRNA) therapeutics are attracting attention as promising tools in cancer immunotherapy due to their ability to leverage the invivo expression of all known protein sequences. Even small amounts of mRNA can have a powerful effect on cancer vaccines by promoting the synthesis of tumor-specific antigens (TSA) or tumor-associated antigens (TAA) by antigen-presenting cells (APC). These antigens are then presented to T cells, eliciting strong antitumor immune stimulation. The potential of mRNA can be further enhanced by expressing immunomodulatory agents, such as cytokines, antibodies, and chimeric antigen receptors (CAR), enhancing tumor immunity. Recent research also explores mRNA-encoded tumor death inducers or tumor microenvironment (TME) modulators. Despite its promise, the clinical translation of mRNA-based anticancer strategies faces challenges, including inefficient targeted delivery invivo, failure of endosomal escape, and inadequate intracellular mRNA release, resulting in poor transfection efficiencies. Inspired by the approval of lipid nanoparticle-loaded mRNA vaccines against coronavirus disease 2019 (COVID-19) and the encouraging outcomes of mRNA-based cancer therapies in trials, innovative nonviral nanotechnology delivery systems have been engineered. These aim to advance mRNA-based cancer immunotherapies from research to clinical application. This review summarizes recent preclinical and clinical progress in lipid and polymeric nanomedicines for delivering mRNA-encoded antitumor therapeutics, including cytokines and antibody-based immunotherapies, cancer vaccines, and CAR therapies. It also addresses advanced delivery systems for direct oncolysis or TME reprogramming and highlights key challenges in translating these therapies to clinical use, exploring future perspectives, including the role of artificial intelligence and machine learning in their development.

Dual-responsive natural killer cell nano-engagers for cancer immunotherapy via inhibiting IL-6/JAK2/STAT3 pathway

Natural killer (NK) cell-based immunotherapy is a promising approach for treating solid tumors and hematological malignancies. However, its therapeutic efficacy is limited by poor tumor infiltration and suppressive tumor microenvironment. Here, we introduce a rapid, simple, and efficient solution: bovine serum albumin-stabilized ultra-small (4 nm) NK cell nano-engagers, termed Bi2Se3@BSA nanodots (Nds). These Nds, responsive to high H2O2 levels in tumor cell environments, enhance near-infrared (NIR)-II photothermic immunotherapy. In vitro and in vivo experiments demonstrate their effectiveness in activating photothermal therapy (PTT)-induced immunogenic cell death (ICD), initiating immune cascade reactions, and stimulating immune response activation. By upregulating NKG2D, RAE-1, and secreting cytokines such as IFN-γ and TNF-α, targeted NK cell infiltration is achieved, reversing the immunosuppressive tumor microenvironment and optimizing NK cell cytotoxicity. Transcriptomic analysis confirms the association of immune response activation with the IL-6/JAK2/STAT3 signaling pathway. Notably, combining these nano-engagers with immune checkpoint inhibitors (aPD-1) significantly enhances therapeutic efficacy, facilitating tumor eradication and reducing recurrence risk. Taken together, NK cell nano-engagers inhibit the IL-6/JAK2/STAT3 signaling pathway, target NK cell activation, stimulate immune functions, and improve the immunosuppressive microenvironment. This study presents an alternative strategy for NK cell-based immunotherapy and highlights this promising tool for cancer immunotherapy.

Hypoxia-Associated GPNMB+ Macrophages Promote Malignant Progression of Colorectal Cancer and Its RelatedRisk Signature Are Powerful Predictive Tool for theTreatment of Colorectal Cancer Patients.

Colorectal cancer (CRC) is a highly malignant tumor with hypoxia being a crucial feature during its progression. This study utilized multiple independent CRC cohorts for bioinformatics analysis and in vitro experiments to investigate the role of hypoxia-related subgroups in CRC. Machine learning was employed to construct risk features associated with this subgroup and further explore its therapeutic value in CRC. The study identified the GPNMB+ Macrophage (GPNMB+ Macr) subgroup as most relevant to hypoxia. GPNMB+ Macr showed significantly higher infiltration in tumor tissues compared to non-tumor tissues, increasing with CRC stage. High infiltration of GPNMB+ Macr was associated with poor prognosis in terms of overall and recurrence-free survival in CRC patients. GPNMB+ Macrophages exhibit M2-like characteristics and have the ability to promote 5-FU resistance, proliferation, and metastasis of CRC cells. The study developed the Hypoxia-Related Macrophage Risk Score (HMRS), which not only served as an independent prognostic factor for CRC patients but also demonstrated robust prognostic performance compared to 84 previously published prognostic features. Patients with low HMRS were sensitive to fluorouracil, oxaliplatin (FOLFOX), and anti-PD-1 immunotherapy, while those with high HMRS showed resistance. Additionally, HMRS was identified as an independent prognostic factor in other digestive tract tumors (hepatocellular carcinoma, pancreatic cancer, esophageal cancer, and gastric cancer), indicating potential extrapolation to other tumor types. In conclusion, GPNMB+ Macr promotes the malignant progression of CRC, and HMRS serves as a powerful predictive tool for prognosis, chemotherapy, and immunotherapy in CRC patients, aiding in improving the quality of survival.

Epithelial-Mesenchymal Transition Related Score Functions as a Predictive Tool for Immunotherapy and Candidate Drugs in Glioma.

Gliomas are aggressive CNS tumors where the epithelial-mesenchymal transition (EMT) is crucial for prognosis. We developed an EMT-based score predicting overall survival (OS) and conducted pathway analyses, revealing functions such as cell proliferation and immune response in glioma progression. The EMT score, correlated with immune functions and cell infiltration, shows potential as an immune response indicator. We identified two promising compounds, BIX02189 and QL-XI-92, as potential glioma treatments based on candidate gene analysis.

An open-label single-center investigator-initiated exploratory clinical study in patients with refractory or recurrent solid tumors using SBRT as “in situ vaccination”: R-ISV-FOLactis trial.

44 Background: The immunotherapy of sarcomas remains a challenge. As a breakthrough tool for cancer immunotherapy, the therapeutic cancer vaccine is in rapid development. In situ vaccination can be realized by intratumoral immune injection and radiotherapy. We have developed a bifunctional engineered Lactococcus lactis (FOLactis) expressing an encoded fusion protein of fms-like tyrosine kinase 3 ligand (Flt3L) and OX40 ligand (OX40L). We hypothesized that intratumoral injection of "FOLactis" combined with SBRT will realize tumor control and the synergetic application of PD-1 mAb systematically will further improve the effect of immunotherapy. Methods: This exploratory clinical study is designed as an open-label trial aimed at treating patients with advanced solid tumors who are unresponsive or intolerable to standard treatment. Patients will be treated with SBRT, intratumoral injection of "FOLactis", and PD-1 blockade. The primary endpoint was the objective response rate (ORR) of target lesions after 3 months and 6 months. The secondary endpoint included the disease control rate (DCR) of target lesions, progression-free survival (PFS), overall survival (OS), etc. Results: From July 2022 to December 2023, 30 patients were eligible for this trial (63% were sarcomas). 53.3% and 33.3% had received radiotherapy or PD-1/PD-L1 mAb before respectively. The ORR and DCR of target lesions after 3 months were 27.6% and 93.1%, while these of systemic efficacy were 17.2% and 55.2%, respectively. In sarcomas, the ORR, DCR of target lesions were 11.1% and 88.9%, while these of systemic efficacy were 5.5% and 50%, respectively. Considering the deferred response in sarcomas, we also calculated the ORR after 6 months as the primary endpoint. The ORR, DCR of target lesions after 6 months were 56.3% and 100%, while these in sarcomas were 41.7% and 100%, respectively. Systemic median PFS were 2.87 months. Median PFS of target lesions and mOS has not reached. Among the evaluable target lesions, 6-month EFS was 50% in sarcomas (6/12) and 50% in all patients (8/16). Expression of CD4+, CD8+ T cells and dendritic cells was significantly increased between pre-treatment and post-treatment peripheral blood in responders. The most common treatment-related adverse events (TRAEs) were fever (83.3%), lymphocytopenia (53.3%), hypocalcemia (30%), neutrophilia (26.7%) and nausea (26.7%). Grade≥3 TRAE occurred in 11 patients, including lymphocytopenia (30%), fever (6.7%), leukopenia (3.3%), anemia (3.3%) and cardiac insufficiency (3.3%). Conclusions: In situ vaccination with“FOLactis", along with SBRT was tolerable and induced anti-tumor immunity, which would also augment systemic response when synergized with PD-1 mAb. This in situ vaccination is probably a promising option for advanced solid tumors. Clinical trial information: ChiCTR2200060660 .

Bacterial outer membrane vesicles in the fight against cancer.

Bacterial outer membrane vesicles (OMVs) are diminutive vesicles naturally released by Gram-negative bacteria. These vesicles possess distinctive characteristics that attract attention for their potential use in drug administration and immunotherapy in cancer treatment. Therapeutic medicines may be delivered via OMVs directly to the tumor sites, thereby minimizing exposure to healthy cells and lowering the risk of systemic toxicity. Furthermore, the activation of the immune system by OMVs has been demonstrated to facilitate the recognition and elimination of cancer cells, which makes them a desirable tool for immunotherapy. They can also be genetically modified to carry specific antigens, immunomodulatory compounds, and small interfering RNAs, enhancing the immune response to cancerous cells and silencing genes associated with disease progression. Combining OMVs with other cancer treatments like chemotherapy and radiation has shown promising synergistic effects. This review highlights the crucial role of bacterial OMVs in cancer, emphasizing their potential as vectors for novel cancer targeted therapies. As researchers delve deeper into the complexities of these vesicles and their interactions with tumors, there is a growing sense of optimism that this avenue of study will bring positive outcomes and renewed hope to cancer patients in the foreseeable future.

Tau-Targeted Immunotherapy for Alzheimer's Disease: Insight into Clinical Trials

The use of immunotherapy as a therapeutic approach to Alzheimer's Disease (AD) is gaining rapid interest, with the primary goal of targeting abnormalities that impact neuronal viability through specific antibodies. Currently, clinical strategies focus intensively on targeting the two main pathologies associated with AD, beta-amyloid (Ab) and tau. This review examines ongoing research in the realm of tau immunotherapy, including clinical trials that demonstrate promising potential for halting AD progression. Several trials are underway, focusing on improving tau-targeted immunotherapy tools based on passive and active immunization protocols. Tau-targeted therapies have proven relevant and demonstrated safety and efficacy in both animal models and human clinical trials. Some studies have demonstrated a reduction in tau protein aggregation in animal models, highlighting a potential mechanism by which these antibodies inhibit the spread of tau protein in the extracellular space. Recent discoveries have highlighted the potential role of tau-targeting therapy with antibodies and have revealed significant promise in treating pathological tau in AD.

Immunotherapy Applications for Thymine Dimers and WT1 Antigen in Renal Cancers: A Comparative Statistical Analysis.

Renal cell carcinoma (RCC) remains incurable in advanced stages. Biomarkers have proven to be quite useful in cancer therapeutics. Herein, we provide a comparative/integrative statistical analysis of seminal immunohistochemistry (IHC) findings for Wilms' Tumor 1 antigen (WT1) and thymine dimers (TDs), emerging as atypical, yet promising, potential biomarkers for RCCs. We assessed WT1/TD reactivity in adult RCC tumor cells, tumor microenvironment (TME), and tumor-adjacent healthy renal tissue (HRT). WT1 positivity was scarce and strictly nuclear in tumor cells, whereas TD-reactive tumor tissues were prevalent. We report statistically significant positive correlations between the density of reactive RCC cellularity and the intensity of nuclear staining for both biomarkers (WT1 - rho = 0.341, p-value = 0.036; TDs - rho = 0.379, p-value = 0.002). RCC stromal TME TD-positivity was much more frequent than WT1 reactivity, apparently proportional to that of the proper RCC cellularity and facilitated by extensive RCC inflammatory infiltration. TDs exhibited nuclear reactivity for most TME cell lines, while RCC TME WT1 expression was rare and inconsistent. In HRTs, TDs were entirely restricted to renal tubular cells, the likely cellular progenitor of most conventional RCC subtypes. In lieu of proper validation, these early findings have significant implications regarding the origins/biology of RCCs and may inform RCC therapeutics, both accounting for the high frequency of immunotherapy-permissive frameshift indels in RCCs, but also hinting at novel predictive clinical tools for WT1-targeted immunotherapy. Overall, the current study represents a meek yet hopefully significant step towards understanding the molecular biology and potential therapeutic targets of RCCs.

Polydopamine nanoparticles cross-linked hyaluronic acid photothermal hydrogel with cascading immunoinducible effects for in situ antitumor vaccination

Tumor vaccine, which can effectively prevent tumor recurrence and metastasis, is a promising tool in tumor immunotherapy. However, heterogeneity of tumors and the inability to achieve a cascade effect limit the therapeutic effects of most developing tumor vaccine. We have developed a cascading immunoinducible in-situ mannose-functionalized polydopamine loaded with imiquimod phenylboronic hyaluronic acid nanocomposite gel vaccine (M/P-PDA@IQ PHA) through a boronic ester-based reaction. This reaction utilizes mannose-functionalized polydopamine loaded with imiquimod (M/P-PDA@IQ NAs) as a cross-linking agent to react with phenylboronic-grafted hyaluronic acid. Under near-infrared light irradiation, the M/P-PDA@IQ PHA caused local hyperthermia to trigger immunogenic cell death of tumor cells and tumor-associated antigens (TAAs) releasing. Subsequently, the M/P-PDA@IQ NAs which were gradually released by the pH/ROS/GSH-triggered degradation of M/P-PDA@IQ PHA, could capture and deliver these TAAs to lymph nodes. Finally, the M/P-PDA@IQ NAs facilitated maturation and cross-presentation of dendritic cells, as well as activation of cytotoxic T lymphocytes. Overall, the M/P-PDA@IQ PHA could serve as a novel in situ vaccine to stimulate several key nodes including TAAs release and capture, targeting lymph nodes and enhanced dendritic cells uptake and maturation as well as T cells activation. This cascading immune activation strategy can effectively elicit antitumor immune response.

Immunogenic cell death-based cancer vaccines: promising prospect in cancer therapy.

Tumor immunotherapy is a promising approach for addressing the limitations of conventional tumor treatments, such as chemotherapy and radiotherapy, which often have side effects and fail to prevent recurrence and metastasis. However, the effectiveness and sustainability of immune activation in tumor immunotherapy remain challenging. Tumor immunogenic cell death, characterized by the release of immunogenic substances, damage associated molecular patterns (DAMPs), and tumor associated antigens, from dying tumor cells (DTCs), offers a potential solution. By enhancing the immunogenicity of DTCs through the inclusion of more immunogenic antigens and stimulating factors, immunogenic cell death (ICD) based cancer vaccines can be developed as a powerful tool for immunotherapy. Integrating ICD nanoinducers into conventional treatments like chemotherapy, photodynamic therapy, photothermal therapy, sonodynamic therapy, and radiotherapy presents a novel strategy to enhance treatment efficacy and potentially improve patient outcomes. Preclinical research has identified numerous potential ICD inducers. However, effectively translating these findings into clinically relevant applications remains a critical challenge. This review aims to contribute to this endeavor by providing valuable insights into the in vitro preparation of ICD-based cancer vaccines. We explored established tools for ICD induction, followed by an exploration of personalized ICD induction strategies and vaccine designs. By sharing this knowledge, we hope to stimulate further development and advancement in the field of ICD-based cancer vaccines.

Tri-specific killer engager: unleashing multi-synergic power against cancer.

Cancer continues to be a global health concern, necessitating innovative solutions for treatment. Tri-specific killer engagers (TriKEs) have emerged as a promising class of immunotherapeutic agents, offering a multifaceted approach to cancer treatment. TriKEs simultaneously engage and activate natural killer (NK) cells while specifically targeting cancer cells, representing an outstanding advancement in immunotherapy. This review explores the generation and mechanisms of TriKEs, highlighting their advantages over other immunotherapies and discussing their potential impact on clinical trials and cancer treatment. TriKEs are composed of three distinct domains, primarily antibody-derived building blocks, linked together by short amino acid sequences. They incorporate critical elements, anti-cluster of differentiation 16 (CD16) and interleukin-15 (IL-15), which activate and enhance NK cell function, together with specific antibody to target each cancer. TriKEs exhibit remarkable potential in preclinical and early clinical studies across various cancer types, making them a versatile tool in cancer immunotherapy. Comparative analyses with other immunotherapies, such as chimeric antigen receptor-T (CAR-T) cell therapy, immune checkpoint inhibitors (ICIs), cytokine therapies, and monoclonal antibodies (mAbs), reveal the unique advantages of TriKEs. They offer a safer pathway for immunotherapy by targeting cancer cells without hyperactivating T cells, reducing off-target effects and complications. The future of TriKEs involves addressing challenges related to dosing, tumor-associated antigen (TAA) expression, and NK cell suppression. Researchers are exploring innovative dosing strategies, enhancing specificity through tumor-specific antigens (TSAs), and combining TriKEs with other therapies for increased efficacy.

Mathematical modeling of interactions between colon cancer and immune system with a deep learning algorithm

Colon cancer is a complex disease with genetically unstable cell lines. In order to better understand the complexity of colon cancer cells and their metastatic mechanisms, we develop a mathematical model in this study. The model is based on a system of fractional-order differential equations and Fractional-Cancer-Informed Neural Networks (FCINN). The model captures a dynamic network of interactions between dendritic cells (DCs), cytotoxic T-cells (CD8+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$8^+$$\\end{document}), helper T-cells (CD4+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$4^+$$\\end{document}), and colon cancer cells through fractional differential equations. By varying the fractional order between 0 and 1, we can classify patients into different groups based on their immune patterns. The goal of this paper is to identify different immune patterns and cancer cell behaviors, as well as the parameters that play an important role in metastasis, control, or elimination of cancer cells in the model. However, several parameters in the model are difficult to estimate in a patient-specific manner. To address this challenge, we use FCINN as an effective deep-learning tool for parameter estimation and numerical simulation of the model. Our findings suggest that the most effective factors in controlling the progression and preventing metastasis of colon cancer are the initial number of cancer cells, the inhibiting rates of tumor cells by DCs, the source of DCs, and the activation of helper T-cells by DCs. These findings suggest that DCs can be used as an immunotherapy tool for the control and treatment of colon cancer.

Deciphering the monocyte-targeting mechanisms of PEGylated cationic liposomes by investigating the biomolecular corona

Cationic liposomes specifically target monocytes in blood, rendering them promising drug-delivery tools for cancer immunotherapy, vaccines, and therapies for monocytic leukaemia. The mechanism behind this monocyte targeting ability is, however, not understood, but may involve plasma proteins adsorbed on the liposomal surfaces. To shed light on this, we investigated the biomolecular corona of three different types of PEGylated cationic liposomes, finding all of them to adsorb hyaluronan-associated proteins and proteoglycans upon incubation in human blood plasma. This prompted us to study the role of the TLR4 co-receptors CD44 and CD14, both involved in signalling and uptake pathways of proteoglycans and glycosaminoglycans. We found that separate inhibition of each of these receptors hampered the monocyte uptake of the liposomes in whole human blood. Based on clues from the biomolecular corona, we have thus identified two receptors involved in the targeting and uptake of cationic liposomes in monocytes, in turn suggesting that certain proteoglycans and glycosaminoglycans may serve as monocyte-targeting opsonins. This mechanistic knowledge may pave the way for rational design of future monocyte-targeting drug-delivery platforms.

Ultrasound-Activated Piezoelectric Nanoparticles Trigger Microglia Activity Against Glioblastoma Cells.

Glioblastoma multiforme (GBM) is the most aggressive brain cancer, characterized by a rapid and drug-resistant progression. GBM "builds" around its primary core a genetically heterogeneous tumor-microenvironment (TME), recruiting surrounding healthy brain cells by releasing various intercellular signals. Glioma-associated microglia (GAM) represent the largest population of collaborating cells, which, in the TME, usually exhibit the anti-inflammatory M2 phenotype, thus promoting an immunosuppressing environment that helps tumor growth. Conversely, "classically activated" M1 microglia could provide proinflammatory and antitumorigenic activity, expected to exert a beneficial effect in defeating glioblastoma. In this work, an immunotherapy approach based on proinflammatory modulation of the GAM phenotype is proposed, through a controlled and localized electrical stimulation. The developed strategy relies on the wireless ultrasonic excitation of polymeric piezoelectric nanoparticles coated with GBM cell membrane extracts, to exploit homotypic targeting in antiglioma applications. Such camouflaged nanotransducers locally generate electrical cues on GAM membranes, activating their M1 phenotype and ultimately triggering a promising anticancer activity. Collected findings open new perspectives in the modulation of immune cell activities through "smart" nanomaterials and, more specifically, provide an innovative auspicious tool in glioma immunotherapy.

CRISPR Technology in Tumor Immunotherapy: Application, limitations, and Improvement Methods

The CRISPR/Cas system is a natural immune mechanism present in prokaryotes, which protects itself by specifically cutting off viral DNA that invades the bacterial body. Under the research of scientists, CRISPR technology has developed into a powerful tool in tumor immunotherapy. It can reduce the inhibitory effect of tumor microenvironment on T cells and enhance tumor immunity by specifically knocking out genes at immune checkpoints (such as PD-1/CTLA-4) on T cells cultured in vitro. However, CRISPR technology also has significant limitations, with the main limitation being its off-target effect - CRISPR is prone to mistakenly identifying and cutting off genes similar to the target gene sequence, including the normal human genome. Once the off-target effect occurs, it will destroy normal genes other than the target gene and cause irreversible damage. Through research, it has been found that CRISPR combined with other technologies can effectively avoid off target effects and reduce treatment risks. This article elaborates on the specific mechanism of CRISPR technology combined with other technologies to avoid off target effects, and explores potential improvement methods.

Abstract 6745: Crafting hyaluronic acid-based nanoparticles for enhanced LN targeting as a potent priming tool in immunotherapy

Abstract Background: Cholesterol-conjugated hyaluronic acid, synthesized by grafting cholesterol moieties onto hyaluronic acid, spontaneously formed nano-sized hydrogel of approximately 30-100nm in water. This hyaluronic acid derivative (HA nanogel) has demonstrated the ability to encapsulate various modalities, including low- and medium-sized molecules, peptides, and proteins. Previous reports have highlighted its efficacy in solubilizing poorly water-soluble drugs and serving as a sustained-release matrix. In this study, we explore the potential of HA nanogels encapsulating antigen peptides with adjuvant as a cancer vaccine and a priming tool for combinational immunotherapy. Method: We prepared HA nanogels as a novel peptide carrier for cancer vaccines and attempted to encapsulate various peptides, including neoantigen (mERK2) peptides expressed in immune checkpoint inhibitor (ICI) therapy-resistant fibrosarcoma cell line CMS5a, gp-100 peptides expressed in metastatic melanoma cell line B16F10, and MAGEA4. Our experiments covered APC uptake, antigen-specific CTL induction, and anti-tumor studies to demonstrate the utility of HA nanogels in these applications. Results: HA nanogel efficiently formed stable complexes with mERK2, gp-100 and MAGEA4 long peptides, each with diameters of 30-100nm. The facile and simple vaccine formulation processes with HA nanogel achieved high drug content and high encapsulation efficiency of 90% or higher. Fluorescently labeled mERK2 long peptide encapsulated in HA nanogel vaccines were subcutaneously administered to BALB/c mice, and uptake analysis of mERK2 long peptides in draining lymph nodes (dLN) was performed using flow cytometry. In comparison to the group receiving mERK2 long peptide without nanogel encapsulation, the HA nanogel group exhibited higher uptake by macrophages and dendritic cells in the dLN. Administering HA nanogel vaccines containing mERK2 long peptides with CpG oligoDNA resulted in higher antigen-specific CD8+ T cells compared to the group receiving mERK2 long peptides without encapsulation. Strong anti-tumor effects were demonstrated in mice models with subcutaneously transplanted CMS5a and B16F10 cell lines. The enhanced efficacy through co-administration with ICI was also confirmed. Conclusion: HA nanogel vaccines efficiently deliver antigen peptides to macrophages and dendritic cells, inducing antigen-specific CTL responses, thereby demonstrating anti-tumor effects against cold tumors such as CMS5a and B16F10. HA nanogels have the potential not only as carriers for cancer vaccines but also as priming tools for combinational immunotherapy. Citation Format: Takashi Nakai, Fumiyasu Momose, Kohei Yabuuchi, Makiko Yamane, Tae Hayashi, Linan Wang, Yoshiyuki Nakagawa, Shogo Aso, Toru Katsumata, Tsuyoshi Shimoboji, Yoshihiro Miyahara. Crafting hyaluronic acid-based nanoparticles for enhanced LN targeting as a potent priming tool in immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6745.

Abstract 6689: Modulation of MAITs by the tumor microbiome in anti-PD1 treated cancers

Abstract Mucosal associated invariant T (MAIT) cells are innate like T-cells that recognize non-peptide metabolite antigens presented on monomorphic MHC related-1 (MR1) making them an attractive off the shelf tool for cancer immunotherapy. In this study, we investigate the function of MAITs in the tumor microenvironment of neoadjuvant anti-PD1 treated lung cancer patients (NCT02259621)). Paired single cell RNA/TCR sequencing analysis revealed an oligoclonal expansion of MAITs comprising of canonical TRAV1-2+ and non-canonical MAITs TRAV1-2-. TCR capture from canonical MAIT clonotypes confirmed their in vitro recognition of 5-OP-RU, bacteria derived riboflavin derivative as well as MR1 dependent recognition of live bacteria present in the tumor. However, the nature of antigens recognized by non-canonical MAITs remains poorly understood. On mining transcriptional profiles of MAITs, we observed that canonical MAITs were characterized by high clonal amplification whereas the non-canonical clonotypes expressed a strong activation/exhaustion gene signature. This suggests that both these MAIT populations recognize different types of antigens, differentially activate, and respond to immune checkpoint blockade (ICB), the non-canonical MAITs being highly dysfunctional. Using bacterial 16S RNA amplicon and metagenomics sequencing, we seek to identify microbial and metabolomics signatures associated with MAIT activation and response to ICB. We identified MAITs to express a cytotoxic signature making them a potential target for cancer immunotherapy. Our findings will provide further insights into the nature of ligands recognized by MAITs and the mechanisms associated with MR1 dependent recognition and tumor killing. Investigating the role of unconventional T-cells in response to ICB has the potential to reveal new tumor-associated antigens which could open avenues into innovative combination immunotherapies. Citation Format: Pakhi Birla, Lansaol Yang, Cynthia Sears, Fyza Shaikh, Drew Pardoll, Franck Housseau. Modulation of MAITs by the tumor microbiome in anti-PD1 treated cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6689.

Abstract 4188: Kyinno PBMC humanized mouse platform: Pioneering service in biomedical research

Abstract Tumor immunotherapy is the use of the human immune system to kill tumors. Compared with traditional chemotherapy and radiotherapy, immunotherapy has significant advantages such as significant efficacy, long-lasting effects, and low toxicity. Wild-type mice are widely used as preclinical models for immunotherapy due to their normal immune system, but they have many shortcomings, such as only being able to inoculate mouse tumor cells, differences between mouse and human immune systems, etc., which cannot accurately simulate the interaction between drugs and tumor cells in the human body. Humanized mouse models include PBMCs humanized mouse models, HSC humanized mouse models, and human embryonic bone, liver, and thymus tissue (BLT) transplantation models. Among them, the PBMCs humanized mouse model is widely used due to its simple preparation, short cycle, and high levels of hCD3+ T cells in the peripheral blood of mice. To assist in the development of immunotherapy, KYINNO has established a PBMC humanized mouse platform that can perform in vivo drug efficacy verification of various immunotherapeutic drugs such as CD3 bispecific antibodies or multi-specific antibodies, immune checkpoint inhibitors, etc. We screen many PBMC donors and select PBMC donors with light GvHD and good hCD3+ T cell reconstruction effects. The drug administration window of the PBMC humanized model has been extended to 6 weeks. Platform verification has been performed on subcutaneous and intravenous injection models of various tumors. Overall, we successfully established the PBMC humanized mouse platform, which is a powerful tool for immunotherapy. Citation Format: Tongtong Liu, Guojin Wu, Feng He, Longtan Luo, Zhengcheng Guo, Shuliang Li, Jinying Ning, Feng Hao. Kyinno PBMC humanized mouse platform: Pioneering service in biomedical research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4188.

Abstract 2664: Targeting PD-L1/CMTM6 in myeloid cells results in elevated release of CCL2 to improve CD8 T cell-mediated antitumor response

Abstract Background: Although targeting myeloid cells has become one of the next generation targets for cancer immunotherapy, there is a lack of therapeutic tools to specifically target these cells. Our group has developed a novel humanized PD-L1-targeting antibody, H1A, that induces PD-L1 degradation via blockade of PD-L1 and CMTM6, therefore limiting PD-L1 intrinsic signaling while also preventing interactions with PD-1. In the immune cell compartment, CMTM6 expression is restricted to myeloid cells, making these cells the primary target of H1A. Recently, we unexpectedly found that targeting intrinsic PD-L1 in myeloid cells via H1A resulted in increased release of CCL2 from myeloid cells. In this study, we examined the role of CCL2/CCR2 signaling in CD8 T cell function using human peripheral blood-derived immune cells and evaluated the therapeutic potential of H1A antibody using our humanized PD-L1/PD-1 mouse model. Methods: Human PBMCs derived from healthy donors were treated with H1A or Atezolizumab, a blocking PD-L1 antibody, followed by mass cytometry and flow cytometry to evaluate immune cell phenotype and functional states. PD-L1 expressing myeloid cells isolated from human PBMCs were treated with H1A or Atezolizumab and assessed for CCL2 secretion using multiplex immunoassays. CCL2 production and transcription were confirmed by flow cytometry and single-cell RNA-sequencing. CCR2 blockade was used on human PBMCs to evaluate the effects of CCL2/CCR2 signaling on T cell function alongside H1A treatment. Finally, in vivo antitumor activity of H1A and Atezolizumab were compared in two humanized PD-L1 tumor models. Results: H1A reduced the frequency of regulatory T cells and increased effector T cells, in whole PBMCs upon global T cell activation with anti-CD3/CD28. H1A enhanced the secretion and production of CCL2 from myeloid cells, which was confirmed at a transcript level. CCR2 blockade diminished CD8 T cells’ ability to differentiate into effector cells in H1A treated PBMCs. H1A demonstrated comparable therapeutic effects with Atezolizumab in treatment of immunogenic and ICI-responsive mouse tumor MC38, which is CD8 T cell-dependent, but showed superior therapeutic effects in treatment of ICI-insensitive mouse tumor E0771 compared to Atezolizumab. Both treatments elicited durable memory specific immune responses upon E0771 tumor rechallenge. Conclusion: H1A demonstrated a superior antitumor activity compared to Atezolizumab in our preclinical models via a new mechanism by which H1A caused degradation of intrinsic PD-L1 in myeloid cells. This causes more release of CCL2 to improve T cell function via CCR2 upon T cell activation. Thus, H1A is emerging as a new immunotherapy tool to target PD-L1/CMTM6 in myeloid cells for treatment of cancers that are refractory to current immune checkpoint inhibitor therapy. Citation Format: Michelle Alexandria Hsu, Xin Liu, Ying Li, Whitney Barham, Kevin Pavelko, Jake Hirdler, Fabrice Lucien, Haidong Dong. Targeting PD-L1/CMTM6 in myeloid cells results in elevated release of CCL2 to improve CD8 T cell-mediated antitumor response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2664.