Search Results (164)

The success of cancer vaccines relies on the ability of dendritic cells (DCs) to efficiently prime cytotoxic CD8 T cell responses against tumors. However, in solid tumors this process is often undermined by tumor-driven immunosuppression and intrinsic defects in DC activation. Among the signaling pathways implicated in DC dysfunction, β-catenin signaling has emerged as a key regulator of immune tolerance in DCs. In parallel, inhibitory receptors such as PD-L1 and TIM-3 on DCs have been recognized as critical DC-intrinsic brakes on CD8 T cell priming and on responses to immune checkpoint blockade (ICB). Recent work has identified a DC-intrinsic immunoregulatory circuit in which β-catenin activation in DCs—particularly in cross-presenting cDC1s—induces expression of TIM-3, thereby suppressing CD8 T cell cross-priming and limiting anti-tumor CD8 T cell immunity. This β-catenin–TIM-3 axis represents a previously underappreciated layer of negative regulation that may help explain, at least in part, the limited efficacy of many current DC-based cancer vaccines. In this review, we examine how β-catenin activation in DCs, particularly in cDC1s, induces TIM-3 and related inhibitory programs that suppress cross-priming of tumor antigen-specific CD8 T cells and constrain the efficacy of DC-based vaccines. We further discuss how selectively targeting this β-catenin–TIM-3 checkpoint axis—alone or together with PD-L1 and other β-catenin–linked receptors—could restore DC function and inform rational combinations of DC-based vaccination with ICB and other T cell-based immunotherapies. Full article

The introduction of immune checkpoint inhibitors (ICIs) as a part of immunotherapy represented a therapeutic breakthrough in the landscape of cancer treatment. The action of these inhibitors consists of blocking certain inhibitory receptors in the immune system. Blocking these inhibitory pathways, ICIs induce an enhanced T cell-mediated response necessary to neutralize tumor cells. Over the last 10 years, programmed death cell protein1 (PD-1), PD ligand 1 (PD-L1), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) have been among the inhibitory receptors most targeted by ICIs. Currently, this innovative therapeutic approach faces two major challenges: early identification of cancer patients who are likely to get a significant therapeutic benefit through the use of these inhibitors, and the second challenge is the early prediction of likely immune-related adverse events (irAEs) associated with such therapy. The aim of the present text is to discuss the current research efforts to discover and develop much needed effective biomarkers, which may represent an important step towards more efficient and risk-free immunotherapy. We also highlight the increasing role in clinical analyses of liquid biopsy sampling combined with mass spectrometry-based proteomics and how such combination is contributing to current research efforts to enhance the role of immunotherapy. Full article

B and T lymphocyte attenuator (BTLA) is a unique co-inhibitory receptor of the CD28 immunoglobulin superfamily that exhibits dual regulatory functions in immune activation and tolerance. Unlike PD-1 or CTLA-4, BTLA interacts bidirectionally with its ligand HVEM, forming a complex signaling network that shapes immune homeostasis within the tumor microenvironment. Dysregulated BTLA expression has been associated with tumor immune evasion and poor prognosis in several cancers. Owing to its distinctive molecular features and multifaceted immunoregulatory roles, BTLA represents an emerging therapeutic target, particularly in tumors unresponsive to conventional immune checkpoint inhibitors. This review provides a comprehensive overview of BTLA’s structure, signaling mechanisms, and functional implications in tumor immunity and discusses current advances and challenges in BTLA-targeted therapy. Finally, we outline future perspectives on leveraging BTLA modulation to enhance cancer immunotherapy outcomes. Full article

Src homology 2-domain containing protein tyrosine phosphatase 2 (SHP2), encoded by the Ptpn11 gene (Tyrosine-protein phosphatase non-receptor type 11), is a key downstream effector of PD-1/PD-L1 signaling and is likely important, in addition to immune modulation, in tumor development and vascular homeostasis. SHP2 conveys PD-1 mediated inhibitory signaling in T cells, and is emerging as a therapeutic target. Importantly, there is an association between immune checkpoint inhibitors (ICIs), immune-related adverse events (irAEs), and cardiovascular complications, underscoring the need to understand SHP2’s role in these processes. This review aims to summarize current knowledge on SHP2/PTPN11 biology, its role in immune regulation, cancer progression, and vascular homeostasis, and to discuss emerging therapeutic strategies targeting this pathway. The concept of using SHP2 inhibitors with immune checkpoint inhibitors (ICIs) is being investigated to address ICI resistance and to improve anti-tumor efficacy substantially. SHP2 is also being studied in non-cancer cell contexts, and signaling responses can differ by large magnitudes depending on the biological context and stimuli. Under normal circumstances, SHP2 promotes vascular homeostasis in endothelial cells (ECs) and myeloid cells and inhibits inflammation, and the reduction in SHP2 activity by oxidative stress, such as in atherosclerosis or diabetes, upregulates inflammation. In contrast, in response to radiation, the fibrotic response and subsequent lung injury were increased by endothelial SHP2 induction via Notch-Jag1 signaling. Vascular smooth muscle cells SHP2 act as a pro-atherogenic effector by enhancing ERK/MAPK signaling, and the upregulation of mitochondria localized SHP2 can also induce cellular senescence-associated inflammation by upregulating mitochondrial reactive oxygen species. Taken together, the two opposite signaling effects of SHP2 suggest that both the immune and vascular system responses appear to be more modulated by the redox, cell, and compartment-specific signaling of SHP2. More studies are needed for mitigating cardiovascular toxicity to patients, particularly with ICI-based treatment regimens. Full article

Background/Objectives: In children developing B-cell acute lymphoblastic leukemia (B-ALL), an immune evasion event takes place where otherwise “silent” preleukemic cells undergo a malignant transformation while escaping immune control, often through unknown mechanisms. Methods and Results: Here, we identify the upregulation of PD-1 expression in preleukemic cells, triggered by Pax5 inactivation in mice and correlating with the time of conversion to leukemia, as a novel marker that favors leukemia evasion. This increase in PD-1 expression is apparent across diverse molecular B-ALL subtypes, both in mice and humans. PD-1 is not required for B-cell leukemogenesis, but, in the absence of PD-1, tumor cells express NK cell inhibitory receptors, highlighting the necessity for leukemic cells to evade the host’s NK immune response in order to exit the bone marrow. PD-1 expression reduces natural antitumor immune responses, but it sensitizes leukemic cells to immune checkpoint blockade strategies in mice and humans. PD-1 targeting confers clinical benefits by restoring NK-mediated tumor cell killing in vitro and eliminating tumor cells in vivo in mice engrafted with B-ALL. Conclusions: These results identify PD-1 as a new therapeutic target against leukemic progression, providing new opportunities for the treatment and possibly also the prevention of childhood B-ALL. Full article

Objective: T cell exhaustion is a major mechanism of immune evasion in cancer, characterized by the sustained expression of multiple inhibitory receptors. This study aimed to evaluate the expression of immune checkpoints in peripheral and tumor-infiltrating CD8⁺ T cells from cervical cancer patients. Methods: We enrolled 104 participants: 37 treatment-naïve patients, 36 treated patients, and 31 age-matched healthy donors. Peripheral blood mononuclear cells (PBMCs) were isolated from all participants. Ten cervical biopsies were collected for tumor-infiltrating lymphocyte (TIL) isolation and paraffin fixation. Immune checkpoint expression was analyzed by multiparametric flow cytometry and immunohistochemistry. Results: In peripheral CD8⁺ T cells, we found a significant upregulation of exhaustion-associated markers PD-1, TIGIT, Tim-3, and LAG-3. In the tumor infiltrating lymphocytes, these same molecules, with the addition of NKG2A, were notably upregulated further. While BTLA and NKG2A showed no systemic changes, NKG2A increased in TILs and BTLA decreased in TILs. The co-expression of PD-1 with TIGIT, Tim-3, LAG-3, and NKG2A was notably enriched between 2- and 6-fold in TILs compared with patient PBMCs. The tumor microenvironment was highly immunosuppressive, characterized by enrichment with PD-1, PD-L1, and TIGIT; TIGIT was notably upregulated in locally advanced versus early-stage tumors. Conclusions: Our findings highlight the strongly immunosuppressive environment of cervical tumors in treatment-naïve patients and the presence of elevated inhibitory checkpoint expression in peripheral blood of both pre- and post-treatment patients. These results underscore the importance of investigating immune regulation within the tumor site itself and suggest that immune checkpoint co-expression may serve as a biomarker of T cell exhaustion and therapeutic resistance. Understanding how treatment alters these pathways could guide rational combination immunotherapies to restore CD8⁺ T cell function in cervical cancer. Full article

Background: Pancreatic ductal adenocarcinoma (PDAC) exhibits marked resistance to immunotherapy. Beyond its characteristically low tumor mutational burden, post-translational modifications (PTMs) remodel the immunopeptidome and promote immune escape through reversible, enzyme-driven programs. Subject Matter: We synthesize evidence that aberrant glycosylation, O-GlcNAcylation, phosphorylation, and citrullination constitute core determinants of antigen visibility operating within spatially discrete tumor niches and a desmoplastic stroma. In hypoxic regions, HIF-linked hexosamine metabolism and OGT activity stabilize immune checkpoints and attenuate antigen processing; at tumor margins, sialylated mucins engage inhibitory Siglec receptors on innate and adaptive lymphocytes; within the stroma, PAD4-dependent NET formation enforces T cell exclusion. We also delineate technical barriers to discovering PTM antigens labile chemistry, low stoichiometry, and method-embedded biases and outline practical solutions: ETD/EThcD/AI-ETD fragmentation, PTM-aware database searching and machine-learning models, and autologous validation in patient-derived organoid–T cell co-cultures. Finally, we highlight therapeutic strategies that either immunize against PTM neoepitopes or inhibit PTM machinery (e.g., PAD4, OGT, ST6GAL1), with stromal remodeling as an enabling adjunct. Conclusions: PTM biology, spatial omics, and patient sample models can uncover targetable niches and speed up PDAC vaccination, TCR, and enzyme-directed treatment development. Full article

Background: Celiac disease (CD) is a gluten-sensitive immune-related enteropathy of the small intestine characterized by villus atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes (IELs). Objectives: To characterize the phenotype of IELs and immune cells of the lamina propria of small intestine control using immuno-oncology and immune-phenotype markers and test the most relevant marker, an immune checkpoint co-inhibitory receptor, leukocyte-associated immunoglobulin-like receptor 1 (LAIR1), in CD. Methods: Immunohistochemical analysis of CD3 (CD3E), CD4, CD8, CD103 (ITGAE), Granzyme B (GZMB), TCR beta (β), TCR delta (δ), CD56 (NCAM), CD16 (FCGR3A), LAIR1 (CD305), PD-L1 (CD274), PD1 (CD279), BTLA (CD272), TOX2, HVEM (TNFRSF14), CD163, HLA-DP-DQ-DR, IL4I1, and FOXP3 was performed using histological analysis. Gene expression analysis was performed using an independent dataset to expand and confirm the findings. Results: IELs exhibited a cytotoxic T-cell phenotype and were CD3+, CD8+, CD103+, TCR beta+, and LAIR1+. The lamina propria (LP) was abundant in CD163+, HLA-DP-DQ-DR+, BTLA+, PD-L1+, CD103+, CD56+, and LAIR1+ cells corresponding to macrophages and T- and B-lymphocytes. In CD, IELs and part of the inflammatory cells of the lamina propria cells were LAIR1+. CD was characterized by higher quantity of LAIR1+ IELs and LP immune cells than the small intestine control (p = 0.004). Higher intestinal lesions evaluated by Marsh scoring were correlated with higher LAIR1 (p < 0.001). Gene expression analysis confirmed the overexpression of the LAIR1 pathway in CD and highlighted BTLA. At the protein level, BTLA overexpression was confirmed in CD. Finally, as a proof-of-concept AI analysis, a convolutional neural network classified LAIR1-stained image patches between the three diagnoses of small intestine control, CD, and reactive tonsils with high accuracy (99.6%). Conclusions: IELs exhibit a cytotoxic T-cell phenotype and were found to be CD3+, CD8+, CD103+, TCR beta+, and LAIR1+ in the small intestine control. Increased numbers of LAIR1+ IELs and lamina propria immune cells characterize CD. Full article

Lymphocyte-activation gene 3 (LAG3) is an immune checkpoint receptor and inhibitory regulator of T-cells. Here, we analyzed the prevalence of LAG3 rs870849 in B-cell lymphoma patients and the treatment outcomes according to the LAG3 genetic background and discovered that LAG3 germline variants may affect the risk of developing lymphoma and also affect the treatment outcome of DLBCL patients in the current CD19 CAR-T cell therapies. The LAG3 rs870849 was prevalent at high frequency in DLBCL patients. Significant differences in treatment outcomes to CAR-T cell therapy emerged in LAG3 I455hom versus I455Thet and T455hom carriers. The overall and complete response rates to CAR-T cell therapy were lower in the I455hom genetic subgroup with median PFS in the I455hom of 2 versus 20 months in the T455hom and I455Thet subgroups (p = 0.025). Median OS was 6 months in the LAG3 I455hom versus 41 months in the T455hom and I455Thet subgroups (p = 0.007). LAG3 rs870849 may affect treatment outcome in CAR-T cell therapy, with favorable outcomes in T455 carriers. Specific combinations of CTLA4 and LAG3 germline variants may cooperate to affect the response to CAR-T cell therapy. Full article

Fusobacterium nucleatum (Fn) has been increasingly recognized as a crucial mediator of colorectal cancer (CRC) biology, particularly in microsatellite-stable (MSS) tumors, where immune checkpoint inhibitors (ICIs) have shown limited efficacy. Rather than representing a passive microbial passenger, Fn actively shapes tumor behavior by adhering to epithelial cells, activating oncogenic signaling, and promoting epithelial–mesenchymal transition (EMT). At the same time, it remodels the tumor microenvironment, driving immune suppression through inhibitory receptor engagement, accumulation of myeloid-derived cells, and metabolic reprogramming of tumor-associated macrophages. These mechanisms converge to impair cytotoxic immunity and contribute to both intrinsic and acquired resistance to ICIs. Beyond immune escape, Fn interferes with conventional chemotherapy by sustaining autophagy and blocking ferroptosis, thereby linking microbial colonization to multidrug resistance. Most of these mechanisms derive from preclinical in vitro and in vivo models, where causal relationships can be inferred. In contrast, human data are mainly observational and provide correlative evidence without proving causality. No interventional clinical studies directly targeting Fn have yet been conducted. Its enrichment across the adenoma–carcinoma sequence and consistent detection in both tumor and fecal samples highlight its potential as a biomarker for early detection and patient stratification. Importantly, multidimensional stool assays that integrate microbial, genetic, and epigenetic markers are emerging as promising non-invasive tools for CRC screening. Therapeutic strategies targeting Fn are also under exploration, ranging from antibiotics and bacteriophages to multifunctional nanodrugs, dietary modulation, and natural microbiota-derived products. These approaches may not only reduce microbial burden but also restore immune competence and enhance the efficacy of immunotherapy in MSS CRC. Altogether, current evidence positions Fn at the intersection of microbial dysbiosis, tumor progression, and therapy resistance. A deeper understanding of its pathogenic role may support the integration of microbial profiling into precision oncology frameworks, paving the way for innovative diagnostic and therapeutic strategies in CRC. Full article

Background/Objectives: Whilst adoptive cell therapy (ACT) using chimeric antigen receptor-engineered T (CAR-T) cells represents an efficient approach for the treatment of patients suffering from several hematological malignancies, solid tumors have been shown to be far more challenging to tackle, mainly due to the hostile tumor microenvironment that inhibits optimal T cell functionality. As proven by the broad clinical success of immune checkpoint inhibitors, blocking the interaction of programmed cell death ligand 1 (PD-L1) expressed on tumor cells and the checkpoint receptor programmed cell death 1 (PD-1) expressed on activated T cells allows an intrinsic T cell-mediated anti-tumor response to be unleashed. We developed a cellular product (MDG1015) consisting of New York esophageal squamous cell carcinoma-1 (NY-ESO-1)/L antigen family member 1a (LAGE-1a)-specific CD8+ T cell receptor-transduced (TCR-)T cells co-expressing the costimulatory switch protein (CSP) PD1-41BB, which turns an inhibitory signal mediated by the PD-1:PD-L1 axis into positive T cell costimulation. Methods: In vitro co-cultures of MDG1015 and PD-L1-positive or -negative target cells were used to analyze TCR-T cell functionality, such as TCR-T (poly-)cytokine release, the killing of target cells, and TCR-T proliferation. The safety of MDG1015 was evaluated via different panels of antigen-negative cell lines or primary cells expressing or lacking PD-L1. Results: Preclinical analyses demonstrated TCR-gated activation of the CSP, leading to enhanced functionality of MDG1015 against antigen-expressing, PD-L1-positive tumor cells without any impact on antigen-negative target cells. Conclusions: The favorable, preclinical functionality and safety profile qualifies MDG1015 as a promising cellular therapy for explorative clinical testing in hard-to-treat solid tumor indications. Full article

Human cytomegalovirus (HCMV) establishes lifelong latency in the host, with the bone marrow (BM) CD34+ cells serving as a key reservoir. To investigate tissue-specific immune responses to CMV, we analysed paired peripheral blood mononuclear cells (PBMCs) and bone marrow mononuclear cells (BMMNCs) from HCMV-seropositive donors using multiparametric flow cytometry and cytokine FluroSpot assays. We assessed immune cell composition, memory T cell subsets, cytokine production, cytotoxic potential, activation marker expression, and checkpoint inhibitory receptor (CIR) profiles, both ex vivo and following stimulation with lytic and latent HCMV antigens. BMMNCs were enriched in CD34+ progenitor cells and exhibited distinct T cell memory subset distributions. HCMV-specific responses were compartmentalised: IFN-γ responses predominated in PBMCs following lytic antigen stimulation, while IL-10 and TNF-α responses were more prominent in BMMNCs, particularly in response to latent antigens. US28-specific T cells in the BM showed elevated expression of CD39, PD-1, BTLA, CTLA-4, ICOS, and LAG-3 on CD4+ T cells and increased expression of PD-1, CD39, BTLA, TIGIT, LAG-3, and ICOS on CD8+ T cell populations, suggesting a more immunoregulatory phenotype. These findings highlight functional and phenotypic differences in HCMV-specific T cell responses between blood and bone marrow, underscoring the role of the BM niche in shaping antiviral immunity and maintaining viral latency. Full article

Despite the successes achieved in recent years in the treatment of childhood acute lymphoblastic leukemia (ALL), high-risk ALL in particular still represents a considerable challenge, with poorer outcomes. The PI3K/AKT/mTOR signaling pathway is frequently constitutively activated in ALL and consequently leads to unrestricted cell proliferation, without showing frequent mutations in the most important representatives of the signaling pathway. Recent studies have shown that fine balanced protein expression is a common way to adjust oncogenic B cell directed receptor signaling and to mediate malignant cell proliferation and survival in leukemic cells. Too low expression of inhibitory phosphatases can lead to constitutive signaling of kinases, which are important for cell proliferation and survival. In contrast, marked high expression levels of key phosphatases enable cells with distinct pronounced oncogenic B cell directed receptor signaling to escape negative selection by attenuating signal strength and thus raising the threshold for deletion checkpoint activation. One of the most important B cell receptor-dependent signaling cascades is the PI3K/AKT signaling pathway, with its important antagonist SHIP1. However, recent data show that the inositol-5-phosphatase SHIP1 is differentially expressed across the heterogeneity of the ALL subtypes, making the overall therapeutic strategy targeting SHIP1 more complex. The aim of this article is therefore to provide an overview of the current knowledge about SHIP1, its expression in the various subtypes of ALL, its regulation, and the molecules that influence its gene and protein expression, to better understand its role in the pathogenesis of leukemia and other human cancers. Full article

Immune checkpoint inhibition is a cornerstone of bladder cancer therapy, but its efficacy in non-urothelial subtypes of bladder cancer is limited, and the prognosis remains poor. Therefore, we investigated the potential of the immune checkpoint molecules TIM-3, TIGIT, and LAG-3 in squamous-cell carcinoma (SCC) and adenocarcinoma (ADENO) of the urinary bladder. Tumor-infiltrating lymphocytes (TILs) showed a high expression of TIM-3 and TIGIT in both SCC and ADENO, while LAG-3-positive TILs were absent in ADENO and present in 46% of SCC. Quantitative analysis revealed age-independent expression of TIM-3 in SCC (r = −0.001, p = 0.997) and ADENO (r = 0.135, p = 0.549), with increasing age correlating with higher expression of TIGIT (r = 0.157, p = 0.242) and LAG-3 (0.106, p = 0.436) in the SCC cohort and of TIGIT (r = 0.276, p = 0.214) in the ADENO cohort. Male patients showed increased TIGIT scores in ADENO (p < 0.01). Of note, a high infiltration of TIM-3-TILs (p = 0.048) correlated with worse progression-free survival in SCC. These results highlight the differential expression of co-inhibitory receptors in non-urothelial bladder cancer subtypes and provide preclinical evidence for new therapeutic targets. Biomarker testing prior to clinical trials is essential for identifying the most suitable patients for targeted immunotherapy. Full article

Chronic hepatitis B (CHB) remains a significant global health concern due to complications like cirrhosis and liver cancer. Immune cell exhaustion, characterized by increased suppressive molecules and inhibitory receptors, represents a critical feature of CHB. Understanding the mechanisms of hepatic immune exhaustion in CHB patients is imperative for the development of effective therapeutic interventions. In this study, we investigated the expression levels and histological distribution of various immune checkpoint receptors and ligands in liver biopsies obtained from CHB patients. Additionally, we aimed to evaluate potential concurrent overexpression of specific receptors and their association with clinical parameters such as ALT levels. Our analysis revealed that PD-1, PD-L1, CTLA-4, TIM-3, GAL-9, CD272, TIGIT, and 2B4 exhibited predominant localization in portal tracts and sinusoids. Furthermore, we observed a correlation between the expression of PD-1, TIM-3, and GAL-9 with ALT levels in CHB patients. Additionally, a strong relationship was identified between the expression of CD272 and TIGIT, as well as between GAL-9 and CTLA-4 within the studied population. Our findings underscore the significance of the TIM-3:GAL-9 pathway in the immunopathogenesis of CHB. This detailed analysis sets the stage for future combined immunotherapy strategies aimed at leveraging checkpoint receptors to enhance clinical outcomes. Full article