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According to the latest evidence, the microbial metabolite Urolithin A (UA), known for its role in promoting cellular health, modulates CD8+ T cell‐mediated antitumor activity. However, the direct target protein of UA and its underlying mechanism remains unclear. Here, this research identifies ERK1/2 as the specific target crucial for UA‐mediated CD8+ T cell activation. Even at low doses, UA markedly enhances the persistence and effector functions of primary CD8+ cytotoxic T lymphocytes (CTLs) and human chimeric antigen receptor (CAR) T cells both in vitro and in vivo. Mechanistically, UA interacts directly with ERK1/2 kinases, enhancing their activation and subsequently facilitating T cell activation by engaging ULK1. The UA‐ERK1/2‐ULK1 axis promotes autophagic flux in CD8+ CTLs, enhancing cellular metabolism and maintaining reactive oxygen species (ROS) levels, as evidenced by increased oxygen consumption and extracellular acidification rates. UA‐treated CD8+ CTLs also display elevated ATP levels and enhanced spare respiratory capacity. Overall, UA activates ERK1/2, inducing autophagy and metabolic adaptation, showcasing its potential in tumor immunotherapy and interventions for diseases involving ERKs. [ABSTRACT FROM AUTHOR]

Personalized cancer vaccines based on resected tumors from patients is promising to address tumor heterogeneity to inhibit tumor recurrence or metastasis. However, it remains challenge to elicit immune activation due to the weak immunogenicity of autologous tumor antigens. Here, a hybrid membrane cancer vaccine is successfully constructed by membrane fusion to enhance adaptive immune response and amplify personalized immunotherapy, which formed a codelivery system for autologous tumor antigens and immune adjuvants. Briefly, the functional hybrid vesicles (HM‐NPs) are formed by hybridizing ginseng‐derived extracellular vesicles‐like particles (G‐EVLPs) with the membrane originated from the resected autologous tumors. The introduction of G‐EVLPs can enhance the phagocytosis of autologous tumor antigens by dendritic cells (DCs) and facilitate DCs maturation through TLR4, ultimately activating tumor‐specific cytotoxic T lymphocytes (CTLs). HM‐NPs can indeed strengthen specific immune responses to suppress tumors recurrence and metastasis including subcutaneous tumors and orthotopic tumors. Furthermore, a long‐term immune protection can be obtained after vaccinating with HM‐NPs, and prolonging the survival of animals. Overall, this personalized hybrid autologous tumor vaccine based on G‐EVLPs provides the possibility of mitigating tumor recurrence and metastasis after surgery while maintaining good biocompatibility. [ABSTRACT FROM AUTHOR]

Immunotherapy targeting PD‐L1 is still ineffective for a wide variety of tumors with high unpredictability. Deploying combined immunotherapy with alternative targeting is practical to overcome this therapeutic resistance. Here, the deficiency of serine‐threonine kinase STK24 is observed in tumor cells causing substantial attenuation of tumor growth in murine syngeneic models, a process relying on cytotoxic CD8+ T and NK cells. Mechanistically, STK24 in tumor cells associates with and directly phosphorylates AKT at Thr21, which promotes AKT activation and subsequent PD‐L1 induction. Deletion or inhibition of STK24, by contrast, blocks IFN‐γ‐mediated PD‐L1 expression. Various murine models indicate that in vivo silencing of STK24 can significantly enhance the efficacy of the anti‐PD‐1 blockade strategy. Elevated STK24 levels are observed in patient specimens in multiple tumor types and inversely correlated with intratumoral infiltration of cytotoxic CD8+ T cells and with patient survival. The study collectively identifies STK24 as a critical modulator of antitumor immunity, which engages in AKT and PD‐L1/PD‐1 signaling and is a promising target for combined immunotherapy. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) has been widely employed in tumor treatment due to its effectiveness. However, the tumor hypoxic microenvironment which is caused by abnormal vasculature severely limits the efficacy of PDT. Furthermore, the abnormal vasculature has been implicated in the failure of immunotherapy. In this study, a novel nanoparticle denoted as Combo‐NP is introduced, composed of a biodegradable NIR II fluorescent pseudo‐conjugate polymer featuring disulfide bonds within its main chain, designated as TPA‐BD, and the vascular inhibitor Lenvatinib. Combo‐NP exhibits dual functionality by not only inducing cytotoxic reactive oxygen species (ROS) to directly eliminate tumor cells but also eliciting immunogenic cell death (ICD). This ICD response, in turn, initiates a robust cascade of immune reactions, thereby augmenting the generation of cytotoxic T lymphocytes (CTLs). In addition, Combo‐NP addresses the issue of tumor hypoxia by normalizing the tumor vasculature. This normalization process enhances the efficacy of PDT while concurrently fostering increased CTLs infiltration within the tumor microenvironment. These synergistic effects synergize to potentiate the photodynamic‐immunotherapeutic properties of the nanoparticles. Furthermore, when combined with anti‐programmed death‐ligand 1 (PD‐L1), they showcase notable inhibitory effects on tumor metastasis. The findings in this study introduce an innovative nanomedicine strategy aimed at triggering systemic anti‐tumor immune responses for the treatment of Uveal melanoma. [ABSTRACT FROM AUTHOR]

Tumor immunotherapy is only effective in a fraction of patients due to a low response rate and severe side effects, and these challenges of immunotherapy in clinics can be addressed through induction of immunogenic cell death (ICD). ICD is elicited from many antitumor therapies to release danger associated molecular patterns (DAMPs) and tumor‐associated antigens to facilitate maturation of dendritic cells (DCs) and infiltration of cytotoxic T lymphocytes (CTLs). The process can reverse the tumor immunosuppressive microenvironment to improve the sensitivity of immunotherapy. Nanostructure‐based drug delivery systems (NDDSs) are explored to induce ICD by incorporating therapeutic molecules for chemotherapy, photosensitizers (PSs) for photodynamic therapy (PDT), photothermal conversion agents for photothermal therapy (PTT), and radiosensitizers for radiotherapy (RT). These NDDSs can release loaded agents at a right dose in the right place at the right time, resulting in greater effectiveness and lower toxicity. Immunotherapeutic agents can also be combined with these NDDSs to achieve the synergic antitumor effect in a multi‐modality therapeutic approach. In this review, NDDSs are harnessed to load multiple agents to induce ICD by chemotherapy, PDT, PTT, and RT in combination of immunotherapy to promote the therapeutic effect and reduce side effects associated with cancer treatment. [ABSTRACT FROM AUTHOR]

Tumor immunotherapy is only effective in a fraction of patients due to a low response rate and severe side effects, and these challenges of immunotherapy in clinics can be addressed through induction of immunogenic cell death (ICD). ICD is elicited from many antitumor therapies to release danger associated molecular patterns (DAMPs) and tumor‐associated antigens to facilitate maturation of dendritic cells (DCs) and infiltration of cytotoxic T lymphocytes (CTLs). The process can reverse the tumor immunosuppressive microenvironment to improve the sensitivity of immunotherapy. Nanostructure‐based drug delivery systems (NDDSs) are explored to induce ICD by incorporating therapeutic molecules for chemotherapy, photosensitizers (PSs) for photodynamic therapy (PDT), photothermal conversion agents for photothermal therapy (PTT), and radiosensitizers for radiotherapy (RT). These NDDSs can release loaded agents at a right dose in the right place at the right time, resulting in greater effectiveness and lower toxicity. Immunotherapeutic agents can also be combined with these NDDSs to achieve the synergic antitumor effect in a multi‐modality therapeutic approach. In this review, NDDSs are harnessed to load multiple agents to induce ICD by chemotherapy, PDT, PTT, and RT in combination of immunotherapy to promote the therapeutic effect and reduce side effects associated with cancer treatment. [ABSTRACT FROM AUTHOR]

SPHK1 (sphingosine kinase-1) catalyzes the phosphorylation of sphingosine to sphingosine-1-phosphate (S1P), is found to be highly expressed in solid tumors. Here, extracellular vesicles (EVs) are identified as the key transporters of SPHK1 to the tumor microenvironment. Consequently, SPHK1-packaged EVs elevate S1P levels in the tumor microenvironment, where S1P appears as an immunosuppressive agent. However, the exact mechanism of how S1P mediates its immunosuppressive effects in cancer is not understood. It is investigated that S1P can induce T cell exhaustion. S1P can also upregulate programmed death ligand-1 (PDL-1) expression through E2F1-mediated transcription. Notably, an SPHK1 inhibitor PF543 improves T cell-mediated cytotoxicity. Furthermore, combining PF543 with an anti-PD-1 antibody reduces tumor burden and metastasis more effectively than PF543 alone in vivo. These data demonstrate a previously unrecognized mechanism of how SPHK1-packaged EVs contribute to the progression of ovarian cancer and thus present the potential clinical application of inhibiting SPHK1/S1P signaling to improve immune checkpoint blockage (anti-PD-1 antibody) therapy in ovarian cancer. [ABSTRACT FROM AUTHOR]

The pathogenic immune response in celiac disease (CeD) is orchestrated by phenotypically distinct CD4+ T cells that recognize gluten epitopes in the context of disease‐associated HLA‐DQ allotypes. Cells with the same distinct phenotype, but with elusive specificities, are increased across multiple autoimmune conditions. Here, whether sorting of T cells based on their distinct phenotype (Tphe cells) yields gluten‐reactive cells in CeD is tested. The method′s efficiency is benchmarked by parallel isolation of gluten‐reactive T cells (Ttet cells), using HLA‐DQ:gluten peptide tetramers. From gut biopsies of 12 untreated HLA‐DQ2.5+ CeD patients, Ttet+/Tphe+, Ttet−/Tphe+, and Ttet−/Tphe− cells are sorted for single‐cell T‐cell receptor (TCR)‐sequencing (n = 8) and T‐cell clone (TCC)‐generation (n = 5). The generated TCCs are TCR sequenced and tested for their reactivity against deamidated gluten. Gluten‐reactivity is observed in 91.2% of Ttet+/Tphe+ TCCs, 65.3% of Ttet−/Tphe+ TCCs and 0% of Ttet−/Tphe− TCCs. TCR sequencing reveals clonal expansion and sequence sharing across patients, features reflecting antigen‐driven responses. The feasibility to isolate antigen‐specific CD4+ T cells by the sole use of phenotypic markers in CeD outlines a potential avenue for characterizing disease‐driving CD4+ T cells in autoimmune conditions. [ABSTRACT FROM AUTHOR]

In the tumor microenvironment, T cells, B cells, and many other cells play important and distinct roles in anti‐tumor immunotherapy. Although the immune checkpoint blockade and adoptive cell transfer can elicit durable clinical responses, only a few patients benefit from these therapies. Increased understanding of tumor‐infiltrating immune cells can provide novel therapies and drugs that induce a highly specific anti‐tumor immune response to certain groups of patients. Herein, the recent research progress on tumor‐infiltrating B cells and T cells, including CD8+ T cells, CD4+ T cells, and exhausted T cells and their role in anti‐tumor immunity, is summarized. Moreover, several anti‐tumor therapy approaches are discussed based on different immune cells and their prospects for future applications in cancer treatment. [ABSTRACT FROM AUTHOR]

The distribution and abundance of immune cells, particularly T‐cell subsets, play pivotal roles in cancer immunology and therapy. T cells have many subsets with specific function and current methods are limited in estimating them, thus, a method for predicting comprehensive T‐cell subsets is urgently needed in cancer immunology research. Here, Immune Cell Abundance Identifier (ImmuCellAI), a gene set signature‐based method, is introduced for precisely estimating the abundance of 24 immune cell types including 18 T‐cell subsets, from gene expression data. Performance evaluation on both the sequencing data with flow cytometry results and public expression data indicate that ImmuCellAI can estimate the abundance of immune cells with superior accuracy to other methods especially on many T‐cell subsets. Application of ImmuCellAI to immunotherapy datasets reveals that the abundance of dendritic cells, cytotoxic T, and gamma delta T cells is significantly higher both in comparisons of on‐treatment versus pre‐treatment and responders versus non‐responders. Meanwhile, an ImmuCellAI result‐based model is built for predicting the immunotherapy response with high accuracy (area under curve 0.80–0.91). These results demonstrate the powerful and unique function of ImmuCellAI in tumor immune infiltration estimation and immunotherapy response prediction. [ABSTRACT FROM AUTHOR]

Vascular disrupting agents (VDAs) have great potential for cancer treatment. Poly(l-glutamic acid)-combretastatin A4 conjugate (PLG-CA4) is a novel class of VDAs. Though it has notable antitumor activity, it can induce host immune responses that promote tumor growth. Here, PLG-CA4 induces the polarization of tumor-associated macrophages (TAMs) toward the M2-like phenotype in 4T1 metastatic breast cancer (Control 30% vs PLG-CA4 53%; p < 0.05). Compared to the monotherapy of PLGCA4, inhibition of phosphoinositide 3-kinase gamma (PI3Kγ) attenuates the immunosuppressive effect of PLG-CA4 treatment by decreasing the number of M2-like TAMs (2.0 × 104 to 1.5 × 104 per tumor) and potential enhancement of cytotoxic T lymphocyte (3.0 × 104 to 5.7 × 104 per tumor). Importantly, PI3Kγ inhibitor synergizing with PLG-CA4 significantly extends the mean survival time from 52 days in monotherapy-treated mice to 61.8 days. Additionally, the combination of PLG-CA4 and PI3Kγ inhibitor improves the tumor therapeutic effect of NLG919, an inhibitor of immune checkpoint indoleamine 2,3-dioxygenase (IDO). As far as it is known, this is the first demonstrated study that VDAs induce the reshaping of macrophages to the M2-like phenotype. The findings also indicate a potential therapeutic strategy of the combination VDAs with an accurate immune modifier in the tumor to reverse the immune resistance. [ABSTRACT FROM AUTHOR]

Cancer immunotherapy based on the engineering of chimeric antigen receptors (CAR) on T cells has emerged as one of the most promising new therapies for patients with B‐cell malignancies. Preclinical assessments of essential CAR T cell functions such as trafficking and cytotoxicity are critical for accelerating the development of highly effective therapeutic candidates. However, current tools for evaluating CAR‐T functions lack sufficient precision. Here, a micropatterned tumor array (MiTA) is described that enables detailed and dynamic characterization of CAR T cell trafficking toward tumor‐cell islands and subsequent killing of tumor cells. It is shown that CAR T cells often merge into large clusters that envelop and kill the tumor cells with high efficiency. Significant differences are also measured between CAR T cells from different donors and between various CAR T cell constructs. Overall, the assay allows for multifaceted, dynamic, high‐content evaluation of CAR T trafficking, clustering, and killing and could eventually become a useful tool for immune‐oncology research and preclinical assessments of cell‐based immunotherapies. [ABSTRACT FROM AUTHOR]