Alginate-based artificial antigen presenting cells expand functional CD8+ T cells with memory characteristics for adoptive cell therapy.

The development of artificial Antigen Presenting Cells (aAPCs) has led to improvements in adoptive T cell therapy (ACT), an immunotherapy, for cancer treatment. aAPCs help to streamline the consistent production and expansion of T cells, thus reducing the time and costs associated with ACT. However, several issues still exist with ACT, such as insufficient T cell potency, which diminishes the translational potential for ACT. While aAPCs have been used primarily to increase production efficiency of T cells for ACT, the intrinsic properties of a biomaterial-based aAPC may affect T cell phenotype and function. In CD8+ T cells, reactive oxygen species (ROS) and oxidative stress accumulation can activate Forkhead box protein O1 (FOXO1) to transcribe antioxidants which reduce ROS and improve memory formation. Alginate, a biocompatible and antioxidant rich biomaterial, is promising for incorporation into an aAPC formulation to modulate T cell phenotype. To investigate its utility, a novel alginate-based aAPC platform was developed that preferentially expanded CD8+ T cells with memory related features. Alginate-based aAPCs allowed for greater control of CD8+ T cell qualities, including, significantly improved in vivo persistence and augmented in vivo anti-tumor T cell responses.

Targeting ACSLs to modulate ferroptosis and cancer immunity.

Five acyl-CoA synthetase long-chain family members (ACSLs) are responsible for catalyzing diverse long-chain fatty acids (LCFAs) into LCFA-acyl-coenzyme A (CoA) for their subsequent metabolism, including fatty acid oxidation (FAO), lipid synthesis, and protein acylation. In this review, we focus on ACSLs and their LCFA substrates and introduce their involvement in regulation of cancer proliferation, metastasis, and therapeutic resistance. Along with the recognition of the decisive role of ACSL4 in ferroptosis - an immunogenic cell death (ICD) initiated by lipid peroxidation - we review the functions of ACSLs on regulating ferroptosis sensitivity. Last, we discuss the current understanding of ACSL on the antitumor immune response. We emphasize the necessity to explore the functions of immune cells expressing ACSLs for developing novel strategies to augment immunotherapy by targeting ACSL.

Pan-cancer and single-cell analysis reveal dual roles of lymphocyte activation gene-3 (LAG3) in cancer immunity and prognosis.

Lymphocyte activating gene-3 (LAG3) is a distinctive T cell co-receptor that is expressed on the surface of lymphocytes. It plays a special inhibitory immune checkpoint role due to its unique domain and signaling pattern. Our aim is to explore the correlation between LAG3 in cancers and physiological processes related to a range of cancers, as well as build LAG3-related immunity and prognostic models. By comprehensively using of datasets and methods from TCGA, GTE-x and GEO databases, cBioPortal, HPA, Kaplan-Meier Plotter, Spearman, CellMinerTM, we delved deeper into the potential impact of the LAG3 in cancer development. These include expression differences, Localization of tumor cell subsets, immune infiltration, matrix infiltration, gene mutations, DNA methylation, signaling pathways and prognosis. Furthermore, we explored LAG3 interactions with different drugs. LAG3 is highly expressed in ACC (p < 0.001), BRCA (p < 0.001), DLBC (p < 0.001), ESCA (p < 0.001), GBM (p < 0.001), HNSC (p < 0.001), KIRC (p < 0.001), LGG (p < 0.001), LUAD (p < 0.01), LUSC (p < 0.001), PAAD (p < 0.001), PCPG (p < 0.01), SKCM (p < 0.001), STAD (p < 0.001), TGCT (p < 0.001) and THCA (p < 0.05), while lowly expressed in COAD (p < 0.001), LIHC (p < 0.05), OV (p < 0.001), PRAD (p < 0.001), READ (p < 0.001), UCEC (p < 0.001) and UCS (p < 0.001). High expression of LAG3 correlates with longer overall survival (OS) in BLCA (HR = 0.67, p < 0.05), CESC (HR = 0.3, p < 0.001), HNSC (HR = 0.67, p < 0.01), LUSC (HR = 0.71, p < 0.05), OV (HR = 0.65, p < 0.01), STAD (HR = 0.68, p < 0.05), and UCEC (HR = 0.57, p < 0.01). Conversely, in KIRC (HR = 1.85, p < 0.001), KIRP (HR = 2.81, p < 0.001), and THYM (HR = 8.92, p < 0.001), high LAG3 expression corresponds to shorter OS. Comprehensive results for recurrence-free survival (RFS) indicate that LAG3 acts as a protective factor in BLCA, CESC, OV, and UCEC. Moreover, LAG3 is widely expressed in tumor-associated lymphocytes, positively correlating with tumor immune scores and stromal scores, and significantly present in the C2 immune subtype across various tumors. High LAG3 expression correlates with increased immune infiltration. LAG3 shows associations with MSI, TMB, and the MMR system, participating in multiple signaling pathways including the T cell receptor pathway. It also demonstrates positive correlations with sensitivity to eleven different drugs. Unlike traditional inhibitory immune checkpoints, LAG3 exhibits dual roles in clinical and immune prognostication across pan-cancers, making it a significant predictive factor. In some cancers, LAG3 serves as a risk factor, indicating adverse clinical outcomes. Conversely, in BLCA, CESC, OV, and UCEC, LAG3 acts as a protective factor associated with longer patient survival. LAG3 demonstrates strong associations within tumor immunity, participating in a range of immune and inflammatory signaling pathways. Elevated levels of LAG3 are linked not only to T cell exhaustion but also to increased immune infiltration and polarization towards M1 macrophages.

CD8+ T-cell exhaustion: Impediment to triple-negative breast cancer (TNBC) immunotherapy.

CD8+ T-cell exhaustion has been identified as a significant contributor to immunosuppression and immune escape in triple-negative breast cancer (TNBC). Dysfunction due to cell exhaustion is characterized by reduced effector capacity and sustained expression of inhibitory receptors (IRs). The factors contributing to CD8+ T-cell exhaustion are multifaceted, encompassing external influences such as the upregulation of IRs, reduction of effector cytokines, and internal changes within the immune cell, including transcriptomic alterations, epigenetic landscape remodeling, and metabolomic shifts. The impact of the altered TNBC tumor microenvironment (TME) on Tex is also a critical consideration. The production of exhausted CD8+ T-cells (CD8+ Tex) is positively correlated with poor prognosis and reduced response rates to immunotherapy in TNBC patients, underscoring the urgent need for the development of novel TNBC immunotherapeutic strategies that target the mechanisms of CD8+ T-cell exhaustion. This review delineates the dynamic trajectory of CD8+ T-cell exhaustion development in TNBC, provides an update on the latest research advancements in understanding its pathogenesis, and offers insights into potential immunotherapeutic strategies.

Triclocarban disrupts the activation and differentiation of human CD8+ T cells by suppressing the vitamin D receptor signaling.

Triclocarban (TCC) is a widely applied environmental endocrine-disrupting chemical (EDC). Similar to most of EDCs, TCC potentially damages the immunity of various species. However, whether and how TCC impacts the adaptive immunity in mammals has yet to be determined. Herein, we discovered that TCC disrupts the activation and differentiation of CD8+ T cells in primary human peripheral blood samples, purified CD8+ T cells, and in mice in vivo. Mechanistically, TCC might block the activation of the vitamin D receptor (VDR) and reduce the synthesis of cholesterol, a precursor of vitamin D, resulting in inhibition of VDR signaling due to the suppression of both its ligand and the receptor itself by TCC. Our findings elucidate the hazard and potential mechanisms of TCC in mammalian adaptive immunity and highlighted VDR as a potential therapeutic target for the immunodeficiency caused by TCC.

CX3CR1+CD8+ T cells: Key players in antitumor immunity.

CX3CR1 functions as the specific receptor for the chemokine CX3CL1, demonstrating expression across a broad spectrum of immune cells. This underscores its pivotal role in communication and response mechanisms within the immune system. Upon engagement with CX3CL1, CX3CR1 initiates a cascade of downstream signaling pathways that regulate various biological functions. In the context of tumor progression, the intricate and inhibitory nature of the tumor microenvironment presents a significant challenge to current clinical treatment techniques. This review aims to comprehensively explore the tumor-destructive potential shown by CX3CR1+CD8+ T cells. Simultaneously, it investigates the promising prospects of utilizing CX3CR1 in future tumor immunotherapies.

CD8+ T cell associated scoring model helps prognostic diagnosis and immunotherapy selection in patients with colon adenocarcinoma.

Objective: T cell-mediated immunity plays a crucial role in the immune response against tumors, with CD 8+ T cells playing a leading role in the eradication of cancer cells. Material and methods: A total of 5 datasets were included in this study. Single cell transcriptome data were used to discover CD8+ T cell marker genes, and Bulk transcriptome data from TCGA and GEO were jointly analyzed to screen candidate prognostic genes. lasso regression was performed to construct prognostic models. Immunotherapy cohort (IMvigor 210 and GSE78220) was applied to validate the diagnostic power of markers. Result: Single-cell transcriptome data identified 65 CD8+ T cell marker genes, highlighting their importance in T cell-mediated immune responses. Among these, 11 genes were identified as CD8+ T-associated differential genes through analysis of bulk data from TCGA and GEO. A prognostic model for 5 genes was identified based on Lasso regression, dividing colon adenocarcinoma (COAD) patients into high- and low-risk groups. This model exhibited higher prognostic accuracy compared to traditional clinicopathological characteristics (age, pathological stage, histological grading). Moreover, the risk score derived from this model successfully differentiated patient responses to immunotherapy, as validated in the IMvigor 210 and GSE78220 cohorts. Conclusion: Our research introduces a novel prognostic signature based on CD8+ T cell marker genes, demonstrating significant predictive power for prognosis and immunotherapy response in COAD patients. This model offers a potential tool for improving patient stratification and personalizing treatment strategies.

Synergistic activity of Enterococcus Faecium-induced ferroptosis via expansion of IFN-γ+CD8+ T cell population in advanced hepatocellular carcinoma treated with sorafenib.

The gut microbiota plays an important role in the development and treatment of hepatocellular carcinoma (HCC). However, the implication of specific gut microbiota in targeted sorafenib therapy for advanced HCC and the microbiota mode of action, remain to be elucidated. Here, we confirmed that four bacterial genera, Lachnoclostridium, Lachnospira, Enterobacter and Enterococcus, are associated with the therapeutic efficacy of Sorafenib, and that Enterobacter faecium (Efm) plays a crucial role in modulating the sorafenib activity. The effective colonization by Emf induced the IL-12 and IFN-γ production and an increased proportion of IFN-γ+CD8+ T cells in the tumor microenvironment. Finally, exopolysaccharides (EPS) from Efm were the primary inducer to prompt IFN-γ+CD8+ T cells to secrete IFN-γ, which together with sorafenib instigated ferroptosis in HCC cells. Collectively, these results indicate that Efm is a promising probiotics that enhances the efficacy of sorafenib treatment in advanced HCC.

CRISPR screens unveil nutrient-dependent lysosomal and mitochondrial nodes impacting intestinal tissue-resident memory CD8+ T cell formation.

Nutrient availability and organelle biology direct tissue homeostasis and cell fate, but how these processes orchestrate tissue immunity remains poorly defined. Here, using in vivo CRISPR-Cas9 screens, we uncovered organelle signaling and metabolic processes shaping CD8+ tissue-resident memory T (TRM) cell development. TRM cells depended on mitochondrial translation and respiration. Conversely, three nutrient-dependent lysosomal signaling nodes-Flcn, Ragulator, and Rag GTPases-inhibited intestinal TRM cell formation. Depleting these molecules or amino acids activated the transcription factor Tfeb, thereby linking nutrient stress to TRM programming. Further, Flcn deficiency promoted protective TRM cell responses in the small intestine. Mechanistically, the Flcn-Tfeb axis restrained retinoic acid-induced CCR9 expression for migration and transforming growth factor ß (TGF-ß)-mediated programming for lineage differentiation. Genetic interaction screening revealed that the mitochondrial protein Mrpl52 enabled early TRM cell formation, while Acss1 controlled TRM cell development under Flcn deficiency-associated lysosomal dysregulation. Thus, the interplay between nutrients, organelle signaling, and metabolic adaptation dictates tissue immunity.

Tumor-associated macrophages and CD8+ T cells: dual players in the pathogenesis of HBV-related HCC.

HBV infection is a key risk factor for the development and progression of hepatocellular carcinoma (HCC), a highly invasive tumor, and is characterized by its persistent immunosuppressive microenvironment. This review provides an in-depth analysis of HBV-related HCC and explores the interactions between neutrophils, natural killer cells, and dendritic cells, examining their roles in regulating tumor-associated macrophages and CD8+ T cells and shaping the tumor microenvironment. Two critical players in the immunosuppressive milieu of HBV-related HCC are CD8+ T cells and tumor-associated macrophages (TAMs). The study explores how TAMs, initially recruited to combat infection, transform, adopting a tumor-promoting phenotype, turning against the body, promoting tumor cell proliferation, suppressing anti-tumor immunity, and assisting in the spread of cancer. Meanwhile, CD8+ T cells, crucial for controlling HBV infection, become dysfunctional and exhausted in response to persistent chronic viral inflammation. The review then dissects how TAMs manipulate this immune response, further depleting CD8+ T cell functions through mechanisms like arginine deprivation and creating hypoxic environments that lead to exhaustion. Finally, it explores the challenges and promising therapeutic avenues that target TAMs and CD8+ T cells, either separately or in combination with antiviral therapy and personalized medicine approaches, offering hope for improved outcomes in HBV-related HCC.

PD-1 endocytosis unleashes the cytolytic potential of checkpoint blockade in tumor immunity.

PD-1 immune checkpoint blockade (ICB) is a key cancer treatment. While blocking PD-1 binding to ligand is known, the role of internalization in enhancing ICB efficacy is less explored. Our study reveals that PD-1 internalization helps unlock ICB's full potential in cancer immunotherapy. Anti-PD-1 induces 50%-60% surface PD-1 internalization from human and mouse cells, leaving low to intermediate levels of resistant receptors. Complexes then appear in early and late endosomes. Both CD4 and CD8 T cells, especially CD8+ effectors, are affected. Nivolumab outperforms pembrolizumab in human T cells, while PD-1 internalization requires crosslinking by bivalent antibody. While mono- and bivalent anti-PD-1 inhibit tumor growth with CD8 tumor-infiltrating cells expressing increased granzyme B, bivalent antibody is more effective where the combination of steric blockade and endocytosis induces greater CD8+ T cell tumor infiltration and the expression of the cytolytic pore protein, perforin. Our findings highlight an ICB mechanism that combines steric blockade and PD-1 endocytosis for optimal checkpoint immunotherapy.

A novel anti-CTLA-4 nanobody-IL12 fusion protein in combination with a dendritic cell/tumour fusion cell vaccine enhances the antitumour activity of CD8+ T cells in solid tumours.

BACKGROUND: We previously developed a nanobody targeting CTLA-4 and demonstrated that it can boost antitumour T-cell responses in vitro; however, the resulting responses after the injection of T cells into cancer models are usually weak and transient. Here, we explored whether fusing our nanobody to IL-12 would enable it to induce stronger, longer-lasting T-cell immune responses after exposure to immature dendritic cell and tumour cell fusions. RESULTS: The fusion protein enhanced the response of CD8+ T cells to tumour antigens in vitro and led to stronger, more persistent immune responses after the T cells were injected into mice bearing different types of xenografts. CONCLUSION: Our in vitro and in vivo results suggest the anticancer potential of our nanobody-interleukin fusion system and support the clinical application of this fusion approach for various nanobodies.

Long-Lasting, Fine-Tuned Anti-Tumor Activity of Recombinant Listeria monocytogenes Vaccine Is Controlled by Pyroptosis and Necroptosis Regulatory and Effector Molecules.

One of the main objectives of developing new anti-cancer vaccine strategies is to effectively induce CD8+ T cell-mediated anti-tumor immunity. Live recombinant vectors, notably Listeria monocytogenes, have been shown to elicit a robust in vivo CD8+ T-cell response in preclinical settings. Significantly, it has been demonstrated that Listeria induces inflammatory/immunogenic cell death mechanisms such as pyroptosis and necroptosis in immune cells that favorably control immunological responses. Therefore, we postulated that the host's response to Listeria-based vectors and the subsequent induction of CD8+ T cell-mediated immunity would be compromised by the lack of regulatory or effector molecules involved in pyroptosis or necroptosis. To test our hypothesis, we used recombinant L. monocytogenes carrying the ovalbumin gene (LM.OVA) to vaccinate wild-type (WT), caspase-1/11-/-, gsdmd-/-, ripk3-/-, and mlkl-/- C57Bl/6 mice. We performed an in vivo cytotoxicity assay to assess the efficacy of OVA-specific CD8+ T lymphocytes in eliminating target cells in wild-type and genetically deficient backgrounds. Furthermore, we evaluated the specific anti-tumor immune response in mice inoculated with the B16F0 and B16F0.OVA melanoma cell lines. Our findings demonstrated that while caspase-1/11 and GSDMD deficiencies interfere with the rapid control of LM.OVA infection, neither of the KOs seems to contribute to the early activation of OVA-specific CTL responses. In contrast, the individual deficiency of each one of these proteins positively impacts the generation of long-lasting effector CD8+ T cells.

Ginsenoside Rg3 activates the immune function of CD8+ T cells via circFOXP1-miR-4477a-PD-L1 axis to induce ferroptosis in gallbladder cancer.

Gallbladder cancer (GBC) is the most common and leading cause of cancer-associated mortality among biliary tract carcinomas worldwide and there is no specific drug for treatment. Activation of CD8+ T cell immune activity is one of the strategies to improve GBC treatment. This study is aimed to investigate the role of Ginsenoside Rg3 on CD8+ T cell activation and pathogenesis of GBC. In GBC cells, Rg3 administration led to the significant reduction of circFOXP1 and PD-L1 as measured by Quantitative real-time polymerase chain reaction (RT-qPCR) and Western blotting. Mechanistically, circFOXP1 acted as the sponge of miR-4477a to regulate PD-L1 expression as demonstrated by RNA pull-down assay and dual luciferase reporter assay. Rg3 treatment enhanced the activity of CD8+ T cells by inhibiting the circFOXP1/miR-4477a/PD-L1 signaling axis. Besides, Rg3 administration induced lipid oxidation and ROS reduction as detected by Flow cytometry, resulting in ferroptosis via the inactivation of circFOXP1/miR-4477a/PD-L1 axis. Ferroptosis inhibitor Fer-1 administration could reverse the beneficial effects caused by Rg3 treatment while ferroptosis inducer Erastin treatment enhanced the effects. Moreover, Rg3 gavage alleviated tumor growth and elevated ferroptosis and apoptosis in tumor tissues, which were prevented by PD-L1 overexpression. Furthermore, Rg3 was demonstrated to activate the function of CD8+ T cells via regulating the circFOXP1-miR-4477a-PD-L1 signaling axis in vivo. Rg3 inactivated the circFOXP1-miR-4477a-PD-L1 signaling axis to activate the immune function of CD8+ T cells, thereby inducing ferroptosis and apoptosis in GBC cells. This research recognizes the mechanism of Rg3-mediated anti-cancer effect and offers evidence for the potentiality of Rg3 in clinical application for GBC therapy.

Redundancy in Innate Immune Pathways That Promote CD8+ T-Cell Responses in AAV1 Muscle Gene Transfer.

While adeno-associated viral (AAV) vectors are successfully used in a variety of in vivo gene therapy applications, they continue to be hampered by the immune system. Here, we sought to identify innate and cytokine signaling pathways that promote CD8+ T-cell responses against the transgene product upon AAV1 vector administration to murine skeletal muscle. Eliminating just one of several pathways (including DNA sensing via TLR9, IL-1 receptor signaling, and possibly endosomal sensing of double-stranded RNA) substantially reduced the CD8+ T-cell response at lower vector doses but was surprisingly ineffective at higher doses. Using genetic, antibody-mediated, and vector engineering approaches, we show that blockade of at least two innate pathways is required to achieve an effect at higher vector doses. Concurrent blockade of IL-1R1 > MyD88 and TLR9 > MyD88 > type I IFN > IFNaR pathways was often but not always synergistic and had limited utility in preventing antibody formation against the transgene product. Further, even low-frequency CD8+ T-cell responses could eliminate transgene expression, even in MyD88- or IL-1R1-deficient animals that received a low vector dose. However, we provide evidence that CpG depletion of vector genomes and including TLR9 inhibitory sequences can synergize. When this construct was combined with the use of a muscle-specific promoter, transgene expression in muscle was sustained with minimal local or systemic CD8+ T-cell response. Thus, innate immune avoidance/blockade strategies by themselves, albeit helpful, may not be sufficient to prevent destructive cellular responses in muscle gene transfer because of the redundancy of immune-activating pathways.

Interventions during Early Infection: Opening a Window for an HIV Cure?

Although combination antiretroviral therapy (ART) has been a landmark achievement for the treatment of human immunodeficiency virus (HIV), an HIV cure has remained elusive. Elimination of latent HIV reservoirs that persist throughout HIV infection is the most challenging barrier to an HIV cure. The progressive HIV infection is marked by the increasing size and diversity of latent HIV reservoirs until an effective immune response is mobilized, which can control but not eliminate HIV infection. The stalemate between HIV replication and the immune response is manifested by the establishment of a viral set point. ART initiation during the early stage limits HIV reservoir development, preserves immune function, improves the quality of life, and may lead to ART-free viral remission in a few people living with HIV (PLWH). However, for the overwhelming majority of PLWH, early ART initiation alone does not cure HIV, and lifelong ART is needed to sustain viral suppression. A critical area of research is focused on determining whether HIV could be functionally cured if additional treatments are provided alongside early ART. Several HIV interventions including Block and Lock, Shock and Kill, broadly neutralizing antibody (bNAb) therapy, adoptive CD8+ T cell therapy, and gene therapy have demonstrated delayed viral rebound and/or viral remission in animal models and/or some PLWH. Whether or not their application during early infection can improve the success of HIV remission is less studied. Herein, we review the current state of clinical and investigative HIV interventions and discuss their potential to improve the likelihood of post-treatment remission if initiated during early infection.

Sensory neuroimmune signaling in the pathogenesis of Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN).

BACKGROUND: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening cutaneous reactions often triggered by medications. While the involvement of CD8+ T cells causing keratinocyte death is well recognized, the contribution of neural elements to the persistent skin inflammation has been largely overlooked. OBJECTIVE: To investigate the potential neuroimmune regulation in SJS/TEN. METHODS: Unbiased single-cell RNA sequencing and flow cytometry were performed using circulating CD8+ T cells from healthy controls and patients with SJS/TEN. ELISA and LEGENDplex assays were respectively used to detect neuropeptides and inflammatory mediators. Skin tissues were examined by immunofluorescence staining for neuropeptide-associated nerves and cytokine receptors. Calcium imaging, Smart-seq, and a 3D skin model were employed for cultured human CD8+ T cells. RESULTS: The unbiased RNA-sequencing revealed an upregulation of the receptor for neuropeptide calcitonin gene-related peptide (CGRP), known as RAMP1, in effector CD8+ T cells in SJS/TEN. Increased CGRP+ nerve fibers and CGRP levels, along with upregulated IL-15R and IL-18R on CD8+ T cells, were displayed in the affected skin of SJS/TEN. The CGRP-RAMP1 axis was necessary and sufficient to enhance receptors for IL-15 and IL-18 and cytotoxic activities in CD8+ T cells, ultimately resulting in keratinocyte apoptosis. Calcium influx was detected in CGRP-stimulated CD8+ T cells. HCN2, a hyperpolarization-activated cation channel, was required for this process and the subsequent cytotoxic effects. CONCLUSIONS: Our study highlights the role of neural elements in regulating CD8+ T cell-mediated inflammatory responses and provides new potential translational targets to improve the outcomes of severe cutaneous drug reactions.

Caerin 1.1 and 1.9 peptides halt B16 melanoma metastatic tumours via expanding cDC1 and reprogramming tumour macrophages.

BACKGROUND: Cancer immunotherapy, particularly immune checkpoint inhibitors (ICBs) such as anti-PD-1 antibodies, has revolutionised cancer treatment, although response rates vary among patients. Previous studies have demonstrated that caerin 1.1 and 1.9, host-defence peptides from the Australian tree frog, enhance the effectiveness of anti-PD-1 and therapeutic vaccines in a murine TC-1 model by activating tumour-associated macrophages intratumorally. METHODS: We employed a murine B16 melanoma model to investigate the therapeutic potential of caerin 1.1 and 1.9 in combination with anti-CD47 and a therapeutic vaccine (triple therapy, TT). Tumour growth of caerin-injected primary tumours and distant metastatic tumours was assessed, and survival analysis conducted. Single-cell RNA sequencing (scRNAseq) of CD45+ cells isolated from distant tumours was performed to elucidate changes in the tumour microenvironment induced by TT. RESULTS: The TT treatment significantly reduced tumour volumes on the treated side compared to untreated and control groups, with notable effects observed by Day 21. Survival analysis indicated extended survival in mice receiving TT, both on the treated and distant sides. scRNAseq revealed a notable expansion of conventional type 1 dendritic cells (cDC1s) and CD4+CD8+ T cells in the TT group. Tumour-associated macrophages in the TT group shifted toward a more immune-responsive M1 phenotype, with enhanced communication observed between cDC1s and CD8+ and CD4+CD25+ T cells. Additionally, TT downregulated M2-like macrophage marker genes, particularly in MHCIIhi and tissue-resident macrophages, suppressing Cd68 and Arg1 expression across all macrophage types. Differential gene expression analysis highlighted pathway alterations, including upregulation of oxidative phosphorylation and MYC target V1 in Arg1hi macrophages, and activation of pro-inflammatory pathways in MHCIIhi and tissue-resident macrophages. CONCLUSION: Our findings suggest that caerin 1.1 and 1.9, combined with immunotherapy, effectively modulate the tumour microenvironment in primary and secondary tumours, leading to reduced tumour growth and enhanced systemic immunity. Further investigation into these mechanisms could pave the way for improved combination therapies in advanced melanoma treatment.

Neudesin regulates dendritic cell function and antitumor CD8+ T cell immunity.

Dendritic cells (DCs) are essential for antitumor T-cell responses to immune checkpoint inhibitor therapies. We have previously reported that the secreted protein neudesin suppresses DC function. In contrast, neudesin has been found to be abundantly expressed in human cancers. In this study, we evaluated the role of neudesin in cancer immunity. Cancer-related database analysis revealed that patients with melanoma with low neudesin expression exhibited increased infiltration of DCs and CD8+ T cells and improved outcomes of checkpoint inhibitor therapy. In mouse tumor models, neudesin deficiency delayed tumor growth and increased the proportions of Type 1 conventional DCs (cDC1s) and tumor antigen-specific CD8+ T cells in tumors and tumor-infiltrating lymph nodes. Neudesin-deficient antitumor cDC1 vaccine enhanced the systemic immunity more effectively than the wild-type cDC1 vaccine. Overall, our findings highlight the importance of neudesin in cancer immunity, providing a novel target for immunotherapy.

Transcriptional rewiring in CD8+ T cells: implications for CAR-T cell therapy against solid tumours.

T cells engineered to express chimeric-antigen receptors (CAR-T cells) can effectively control relapsed and refractory haematological malignancies in the clinic. However, the successes of CAR-T cell therapy have not been recapitulated in solid tumours due to a range of barriers such as immunosuppression, poor infiltration, and tumour heterogeneity. Numerous strategies are being developed to overcome these barriers, which include improving culture conditions and manufacturing protocols, implementing novel CAR designs, and novel approaches to engineering the T cell phenotype. In this review, we describe the various emerging strategies to improve CAR T cell therapy for solid tumours. We specifically focus on new strategies to modulate cell function and fate that have precipitated from the growing knowledge of transcriptional circuits driving T cell differentiation, with the ultimate goal of driving more productive anti-tumour T cell immunity. Evidence shows that enrichment of particular phenotypic subsets of T cells in the initial cell product correlates to improved therapeutic responses and clinical outcomes. Furthermore, T cell exhaustion and poor persistence are major factors limiting therapeutic efficacy. The latest preclinical work shows that targeting specific master regulators and transcription factors can overcome these key barriers, resulting in superior T cell therapeutic products. This can be achieved by targeting key transcriptional circuits promoting memory-like phenotypes or sustaining key effector functions within the hostile tumour microenvironment. Additional discussion points include emerging considerations for the field such as (i) targeting permutations of transcription factors, (ii) transient expression systems, (iii) tissue specificity, and (iv) expanding this strategy beyond CAR-T cell therapy and cancer.