Blockade of LAG-3 and PD-1 leads to co-expression of cytotoxic and exhaustion gene modules in CD8+ T cells to promote antitumor immunity

Systemic Therapy for Melanoma: What Surgeons Need to Know

Immune checkpoint inhibitors and targeted therapies (BRAF/MEK inhibitors) have transformed the care of patients with stage IV melanoma, now with 5-year overall survival rates around 50%. Surgeons should be acquainted with these drugs, the multidisciplinary considerations of their use, and the unique immune-related adverse events (irAEs) they can cause. In this review, we discuss systemic therapies for cutaneous melanoma, including the biology of immune checkpoint inhibition, treatment indications, and toxicities. We also explain how these irAEs and other toxicities can impact surgical planning and perioperative management.

One Step Ahead: Preventing Tumor Adaptation to Immune Therapy

Immune checkpoint inhibitors are cancer therapeutics that have shown remarkable success in extending lives in many cancers, including melanoma, MSI-high cancers, and other cancers. However, these therapeutics have not shown benefit for many patients with cancer, especially those with advanced cancer diagnoses. In addition, many patients develop resistance to these therapeutics and/or life-altering adverse events that can include cardiotoxicity, pneumonitis, thyroiditis, pancreatitis, and hepatitis. Extensive efforts to improve cancer care by uncovering mechanisms of resistance to immune therapy in solid tumors have led to identification of new sources of resistance and to the development of new approaches to activate or sustain antitumor immunity. Chronic stimulation of T cells by tumors and by checkpoint inhibitors can lead to a progressive state of T-cell exhaustion. Chronic T-cell activation by the tumor microenvironment (TME) or immune therapeutics can upregulate the expression and function of alternate checkpoints, including the T-cell protein LAG-3. Persistent interferon signaling in the TME can drive epigenetic changes in cancer cells that enable tumors to counter immune activation and disrupt tumor cell elimination. In addition, immune-suppressive macrophages can flood tumors in response to signals from dying tumor cells, further preventing effective immune responses. New clinical developments and/or approvals for therapies that target alternate immune checkpoints, such as the T-cell checkpoint LAG-3; myeloid cell proteins, such as the kinase phosphoinositide 3-kinase gamma isoform; and chronic interferon signaling, such as Jak 1 inhibitors, have been approved for cancer care or shown promise in recent clinical trials.

Neoantigens combined with in situ cancer vaccination induce personalized immunity and reshape the tumor microenvironment

Neoantigen (nAg) vaccines can induce anti-tumor specific immunity, and tumor killing promotes further antigen diffusion, which is expected to improve prognosis. However, the mutation of cancer cells under the selective pressure of vaccines and the immunosuppressive tumor microenvironment make the therapeutic effect unsatisfactory. Here, we develop a nanovaccine (nAg-MRDE/Mn) that can deliver nAg and induce in situ cancer vaccination to synergistically promote a personalized immune response, enhance antigen diffusion, and improve the microenvironment by modulating immunosuppressive cells and activating the innate immune response. Experiments show that nAgs are presented by dendritic cells and expressed by T cells, which cooperate with in situ vaccination to stimulate specific immunity. Cells involved in immunosuppression, such as M2 macrophages and regulatory T cells, are down-regulated, while M1 macrophages and natural killer cells are increased. In addition, the hydrogel loaded with chemokines and nAg-MRDE/Mn inhibits postoperative tumor recurrence, and the combination of nAg-MRDE/Mn and αPD-1 improves the therapeutic effect of αPD-1. This study validates the clinical potential of this strategy and provides ideas for improving neoantigen vaccines.

Immunotherapy in microsatellite-stable colorectal cancer: Strategies to overcome resistance

Colorectal cancer (CRC) is among the foremost causes of cancer-related mortality worldwide; however, individuals with microsatellite-stable (MSS) disease-who constitute most CRC diagnoses-derive limited benefit from existing immunotherapeutic approaches. Here, we outline emerging methods designed to address the inherent resistance of MSS CRC to immune checkpoint inhibitors (ICIs). Recent findings emphasize how the immunosuppressive tumor microenvironment (TME) in MSS CRC, marked by diminished immunogenicity and high levels of regulatory T cells and myeloid-derived suppressor cells, restricts effective antitumor immune activity. Combination regimens that merge ICIs with chemotherapy, anti-angiogenic agents, or targeted blockade of pathways such as TGF-β and VEGF have shown encouraging early outcomes, including enhanced antigen presentation and T-cell penetration. Novel immunomodulatory platforms-such as epigenetic modifiers, oncolytic viruses, and engineered probiotic vaccines-are under assessment to further reprogram the TME and boost therapeutic efficacy. Concurrently, progress in adoptive cell therapies (for example, chimeric antigen receptor (CAR) T cells) and the development of cancer vaccines targeting tumor-associated and neoantigens promise to extend immune control over MSS CRC. In parallel, improving patient selection through predictive biomarkers-from circulating tumor DNA (ctDNA) to gene expression signatures and specific molecular subtypes-could refine individualized treatment strategies. Finally, interventions that alter the gut microbiome, including probiotics and fecal transplantation, serve as complementary tools to strengthen ICI responses. Taken together, these insights and combined treatment strategies lay the foundation for more successful immunotherapeutic interventions in MSS CRC, ultimately aiming to provide sustained clinical benefits to a broader spectrum of patients.

Engineered hybrid cell membrane nanovesicles for potentiated cancer immunotherapy through dual immune checkpoint inhibition

Immune checkpoint inhibitors (ICIs) have demonstrated remarkable success in treating various types of solid tumors; however, only a limited number of patients currently benefit from these therapeutic agents. Developing novel ICIs that elicit systemic and durable antitumor immune responses remains a significant challenge in improving immunotherapy outcomes. In this study, we engineered PD-1/LAG-3 receptors onto cell membrane nanovesicles to simultaneously block two immune checkpoints for the treatment of colorectal cancer. This dual-checkpoint blockade strategy led to significantly more potent tumor growth suppression in mice with MC38 xenografts compared to nanovesicles targeting PD-1 or LAG-3 alone. Notably, the hybrid nanovesicles substantially rejuvenated exhausted CD8+ T cells, promoting dendritic cell maturation and depleting regulatory T cells (Tregs). This research highlights the promising potential of cell membrane nanovesicles as an effective platform for delivering multiple immune checkpoints in cancer immunotherapy, offering a novel strategy to enhance therapeutic efficacy.

Ligand-induced ubiquitination unleashes LAG3 immune checkpoint function by hindering membrane sequestration of signaling motifs

Lymphocyte activation gene 3 (LAG3) has emerged as a promising cancer immunotherapy target, but the mechanism underlying LAG3 activation upon ligand engagement remains elusive. Here, LAG3 was found to undergo robust non-K48-linked polyubiquitination upon ligand engagement, which promotes LAG3's inhibitory function instead of causing degradation. This ubiquitination could be triggered by the engagement of major histocompatibility complex class II (MHC class II) and membrane-bound (but not soluble) fibrinogen-like protein 1 (FGL1). LAG3 ubiquitination, mediated redundantly by the E3 ligases c-Cbl and Cbl-b, disrupted the membrane binding of the juxtamembrane basic residue-rich sequence, thereby stabilizing the LAG3 cytoplasmic tail in a membrane-dissociated conformation enabling signaling. Furthermore, LAG3 ubiquitination is crucial for the LAG3-mediated suppression of antitumor immunity in vivo. Consistently, LAG3 therapeutic antibodies repress LAG3 ubiquitination, correlating with their checkpoint blockade effects. Moreover, patient cohort analyses suggest that LAG3/CBL coexpression could serve as a biomarker for response to LAG3 blockade. Collectively, our study reveals an immune-checkpoint-triggering mechanism with translational potential in cancer immunotherapy.

Resistance to anti-LAG-3 plus anti-PD-1 therapy in head and neck cancer is mediated by Sox9+ tumor cells interaction with Fpr1+ neutrophils

Relatlimab and nivolumab combination therapy shows significant efficacy in treating various types of cancer. Current research on the molecular mechanisms of this treatment is abundant, but in-depth investigations into post-treatment resistance remain notably lacking. In this study, we identify significant enrichment of SRY (sex determining region Y)-box 9 (Sox9)+ tumor cells in resistant samples using single cell RNA sequencing (scRNAseq) in a head and neck squamous cell carcinoma (HNSCC) mouse model. In addition, Sox9 directly regulates the expression of annexin A1 (Anxa1), mediating apoptosis of formyl peptide receptor 1 (Fpr1)+ neutrophils through the Anxa1-Fpr1 axis, which promotes mitochondrial fission, inhibits mitophagy by downregulating BCL2/adenovirus E1B interacting protein 3 (Bnip3) expression and ultimately prevents the accumulation of neutrophils in tumor tissues. The reduction of Fpr1+ neutrophils impairs the infiltration and tumor cell-killing ability of cytotoxic Cd8 T and γδT cells within the tumor microenvironment, thereby leading to the development of resistance to the combination therapy. We further validate these findings using various transgenic mouse models. Overall, this study comprehensively explains the mechanisms underlying resistance to the anti-LAG-3 plus anti-PD-1 combination therapy and identifies potential therapeutic targets to overcome this resistance.

Single-cell analysis unveils immune dysregulation and EBV-driven lymphoproliferative disorder in pediatric liver transplant recipients

Post-transplant lymphoproliferative disorder (PTLD) is a severe complication following liver transplantation, particularly in pediatric patients, with a high incidence rate associated with Epstein-Barr virus (EBV) infection. The immunological microenvironment of PTLD, particularly the cellular and molecular changes associated with EBV infection, remains unclear. Using scRNA-seq, we examined changes in the immune microenvironment of PBMC from pediatric liver transplant recipients across four groups: PTLD patients with EBV infection, EBV-positive non-PTLD transplant recipients, EBV-negative transplant recipients, and healthy children. PTLD patients exhibited profound immune dysregulation, marked by weakened cytotoxicity in NK cells, reduced B cell differentiation and activation, and an inflammatory shift in myeloid cells. EBV infection primarily targeted memory B cells and plasma cells in PTLD patients, with uninfected memory B cells showing impaired functional potential. Furthermore, CD8+ T cells in PTLD were characterized by increased exhaustion and low cytotoxic activity. In addition, regulatory T cells in PTLD displayed enhanced suppressive functions. Our findings present an in-depth view of the immune landscape in PTLD, identifying key immune cell alterations associated with EBV infection and PTLD development. These insights could inform the development of targeted therapies aimed at restoring immune function and controlling EBV-driven lymphoproliferation in pediatric liver transplant recipients.

LAG3, TIM3 and TIGIT: New Targets for Immunotherapy and Potential Associations with Radiotherapy

The combination of immunotherapy and radiotherapy has demonstrated synergistic potential, especially when a combination of immune checkpoint inhibitors (ICIs) is administered. Cytotoxic T-Lymphocyte-Associated Protein-4 (CTLA-4) inhibitors and Programmed Death-Ligand 1 (PD-L1) inhibitors or Programmed Cell Death Protein 1 (PD-1) inhibitors have been assessed in both clinical and preclinical studies; the addition of radiotherapy activates immunomodulatory mechanisms materialized by an effect similar to "in situ" vaccination or the "abscopal" distant response of lesions outside the irradiation field. The new therapeutic targets (T cell immune-receptor with Ig and ITIM domains (TIGIT), Lymphocyte activating gene 3 (LAG-3), and T cell Ig- and mucin-domain-containing molecule-3 (TIM-3)) associated with traditional ICIs and radiotherapy open new perspectives to the concept of immuno-radiotherapy. The dynamic evaluation of T lymphocyte expression involved in the antitumor immune response, both in the tumor microenvironment (TME) and in the tumor itself, could have biomarker value in assessing the response to combination therapy with traditional and new ICIs in association with irradiation. Preclinical data justify the initiation of clinical trials in various tumor pathologies to explore this concept.

Navigating established and emerging biomarkers for immune checkpoint inhibitor therapy

Immune checkpoint inhibitors (ICIs) have improved outcomes of patients with many different cancers. These antibodies target molecules such as programmed cell death 1 (PD-1) or cytotoxic T lymphocyte associated protein 4 (CTLA-4) which normally function to limit immune activity. Treatment with ICIs reactivates T cells to destroy tumor cells in a highly specific manner, which in some patients, results in dramatic remissions and durable disease control. Over the last decade, much effort has been directed at characterizing factors that drive efficacy and resistance to ICI therapy. Food and Drug Administration (FDA)-approved biomarkers for ICI therapy have facilitated more judicious treatment of cancer patients and transformed the field of precision oncology. Yet, adaptive immunity against cancers is complex, and newer data have revealed the potential utility of other biomarkers. In this review, we discuss the utility of currently approved biomarkers and highlight how emerging biomarkers can further improve the identification of patients who benefit from ICIs.

CD8+ T Cell Subsets as Biomarkers for Predicting Checkpoint Therapy Outcomes in Cancer Immunotherapy

The advent of immune checkpoint blockade (ICB) has transformed cancer immunotherapy, enabling remarkable long-term outcomes and improved survival, particularly with ICB combination treatments. However, clinical benefits remain confined to a subset of patients, and life-threatening immune-related adverse effects pose a significant challenge. This limited efficacy is attributed to cancer heterogeneity, which is mediated by ligand-receptor interactions, exosomes, secreted factors, and key transcription factors. Oncogenic regulators like E2F1 and MYC drive metastatic tumor environments and intertwine with immunoregulatory pathways, impairing T cell function and reducing immunotherapy effectiveness. To address these challenges, FDA-approved biomarkers, such as tumor mutational burden (TMB) and programmed cell death-ligand 1 (PD-L1) expression, help to identify patients most likely to benefit from ICB. Yet, current biomarkers have limitations, making treatment decisions difficult. Recently, T cells-the primary target of ICB-have emerged as promising biomarkers. This review explores the relationship between cancer drivers and immune response, and emphasizes the role of CD8+ T cells in predicting and monitoring ICB efficacy. Tumor-infiltrating CD8+ T cells correlate with positive clinical outcomes in many cancers, yet obtaining tumor tissue remains complex, limiting its practical use. Conversely, circulating T cell subsets are more accessible and have shown promise as predictive biomarkers. Specifically, memory and progenitor exhausted T cells are associated with favorable immunotherapy responses, while terminally exhausted T cells negatively correlate with ICB efficacy. Ultimately, combining biomarkers enhances predictive accuracy, as demonstrated by integrating TMB/PD-L1 expression with CD8+ T cell frequency. Computational models incorporating cancer and immune signatures could further refine patient stratification, advancing personalized immunotherapy.

The response to anti-PD-1 and anti-LAG-3 checkpoint blockade is associated with regulatory T cell reprogramming

Immune checkpoint blockade (ICB) has revolutionized cancer treatment; however, many patients develop therapeutic resistance. We previously identified and validated a pretreatment peripheral blood biomarker, characterized by a high frequency of LAG-3+ lymphocytes, that predicts resistance in patients receiving anti-PD-1 (aPD-1) ICB. To better understand the mechanism of aPD-1 resistance, we identified murine tumor models with a high LAG-3+ lymphocyte frequency (LAG-3hi), which were resistant to aPD-1 therapy, and LAG-3lo murine tumor models that were aPD-1 sensitive, recapitulating the predictive biomarker we previously described in patients. LAG-3hi tumor-bearing mice were sensitive to aPD-1 + anti-LAG-3 (aLAG-3) therapy, and this benefit was CD8+ T cell dependent. The efficacy of combination therapy was enhanced in LAG-3hi (but not LAG-3lo) mice with depletion of CD4+ T cells. Furthermore, responses to aPD-1 + aLAG-3 correlated with regulatory T cell (Treg) phenotypic plasticity in LAG-3hi mice, suggesting a specific role for Tregs in response to aPD-1 + aLAG-3 treatment. Using Treg fate-tracking Foxp3GFP-Cre-ERT2 × ROSAYFP reporter mice, we demonstrated that expanded populations of unstable Tregs correlated with improved response to combination therapy in LAG-3hi mice. Complementing these preclinical data, an increased proportion of unstable Tregs also correlated with higher response rate and improved survival after aPD-1 + aLAG-3 therapy in a cohort of patients with metastatic melanoma (n = 117). These data indicate that Treg phenotypic plasticity affects aPD-1 + aLAG-3 responsiveness, which may represent a biomarker to aid patient selection and a rational therapeutic target for a subset of PD-1-refractory patients.

T cell-based cancer immunotherapy: opportunities and challenges

T cells play a central role in the cancer immunity cycle. The therapeutic outcomes of T cell-based intervention strategies are determined by multiple factors at various stages of the cycle. Here, we summarize and discuss recent advances in T cell immunotherapy and potential barriers to it within the framework of the cancer immunity cycle, including T-cell recognition of tumor antigens for activation, T cell trafficking and infiltration into tumors, and killing of target cells. Moreover, we discuss the key factors influencing T cell differentiation and functionality, including TCR stimulation, costimulatory signals, cytokines, metabolic reprogramming, and mechanistic forces. We also highlight the key transcription factors dictating T cell differentiation and discuss how metabolic circuits and specific metabolites shape the epigenetic program of tumor-infiltrating T cells. We conclude that a better understanding of T cell fate decision will help design novel strategies to overcome the barriers to effective cancer immunity.

PD-L1/PD-1 checkpoint pathway regulates astrocyte morphogenesis and myelination during brain development

Programmed cell death protein 1 (PD-1) and its primary ligand PD-L1 are integral components of a significant immune checkpoint pathway, widely recognized for its central role in cancer immunotherapy. However, emerging evidence highlights their broader involvement in both the central and peripheral nervous systems. In this study, we demonstrate that PD-L1/PD-1 signaling in astrocytes during mouse brain development regulates astrocyte maturation and morphogenesis via the MEK/ERK pathway by targeting the downstream effector cysteine and glycine rich protein 1 (CSRP1). This enhanced astrocyte morphological complexity results in increased end-foot coverage of blood vessels. Additionally, aberrant secretion of CSRP1 by astrocytes interacts with oligodendrocyte precursor cells (OPCs) membrane proteins annexin A1 (ANXA1) and annexin A2 (ANXA2), leading to the exclusion of migrating OPCs from blood vessels. This disruption in OPC migration and differentiation results in abnormal myelination and is associated with cognitive deficits in the mice. Our results provide critical insights into the function of PD-L1/PD-1 signaling in astrocyte-OPC interactions and underscore its relevance to glial cell development and pathogenesis in neurodevelopmental disorders.

Lag3 and PD-1 pathways preferentially regulate NFAT-dependent TCR signalling programmes during early CD4+ T cell activation

Introduction

Lag3 and PD-1 are immune checkpoints that regulate T cell responses and are current immunotherapy targets. Yet how they function to control early stages of CD4+ T cell activation remains unclear.

Methods

Here, we show that the PD-1 and Lag3 pathways exhibit layered control of the early CD4+ T cell activation process, with the effects of Lag3 more pronounced in the presence of PD-1 pathway co-blockade (CB). RNA sequencing revealed that CB drove an early NFAT-dependent transcriptional profile, including promotion of ICOShi T follicular helper cell differentiation.

Results

NFAT pathway inhibition abolished CB-induced upregulation of NFAT-dependent co-receptors ICOS and OX40, whilst unaffecting the NFAT-independent gene Nr4a1. Mechanistically, Lag3 and PD-1 pathways functioned additively to regulate the duration of T cell receptor signals during CD4+ T cell re-activation. Phenotypic changes in peripheral blood CD4+ T cells in humans on anti-Lag3 and anti-PD-1 combination therapy revealed upregulation of genes encoding ICOS and OX40 on distinct CD4+ T cell subsets, highlighting the potential translational relevance of our findings.

Conclusion

Our data therefore reveal that PD-1 and Lag3 pathways converge to additively regulate TCR signal duration and may preferentially control NFAT-dependent transcriptional activity during early CD4+ T cell re-activation.

Dual role of interferon-gamma in the response of melanoma patients to immunotherapy with immune checkpoint inhibitors

Interferon-gamma (IFN-γ) is a cytokine produced mainly by immune cells and can affect cancer cells by modulating the activity of multiple signaling pathways, including the canonical Janus-activated kinase/signal transducer and activator of transcription (JAK/STAT) cascade. In melanoma, IFN-γ can exert both anticancer effects associated with cell-cycle arrest and cell death induction and protumorigenic activity related to immune evasion leading to melanoma progression. Notably, IFN-γ plays a crucial role in the response of melanoma patients to immunotherapy with immune checkpoint inhibitors (ICIs), which are currently used in the clinic. As these agents target programmed death-1 (PD-1) and its ligand (PD-L1), cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) and lymphocyte-activation gene 3 (LAG-3), they are designed to restore the antimelanoma immune response. In this respect, IFN-γ produced by cells in the tumor microenvironment in response to ICIs has a beneficial influence on both immune and melanoma cells by increasing antigen presentation, recruiting additional T-cells to the tumor site, and inducing direct antiproliferative effects and apoptosis in melanoma cells. Therefore, IFN-γ itself and IFN-γ-related gene signatures during the response to ICIs can constitute biomarkers or predictors of the clinical outcome of melanoma patients treated with ICIs. However, owing to its multifaceted roles, IFN-γ can also contribute to developing mechanisms associated with the acquisition of resistance to ICIs. These mechanisms can be associated with either decreased IFN-γ levels in the tumor microenvironment or diminished responsiveness to IFN-γ due to changes in the melanoma phenotypes associated with affected activity of other signaling pathways or genetic alterations e.g., in JAK, which restricts the ability of melanoma cells to respond to IFN-γ. In this respect, the influence of IFN-γ on melanoma-specific regulators of the dynamic plasticity of the cell phenotype, including microphthalmia-associated transcription factor (MITF) and nerve growth factor receptor (NGFR)/CD271 can affect the clinical efficacy of ICIs. This review comprehensively discusses the role of IFN-γ in the response of melanoma patients to ICIs with respect to its positive influence and role in IFN-γ-related mechanisms of resistance to ICIs as well as the potential use of predictive markers on the basis of IFN-γ levels and signatures of IFN-γ-dependent genes.

Emerging immunotherapies in osteosarcoma: from checkpoint blockade to cellular therapies

Osteosarcoma remains a highly aggressive bone malignancy with limited therapeutic options, necessitating novel treatment strategies. Immunotherapy has emerged as a promising approach, yet its efficacy in osteosarcoma is hindered by an immunosuppressive tumor microenvironment and resistance mechanisms. This review explores recent advancements in checkpoint blockade, cellular therapies, and combination strategies aimed at enhancing immune responses. We highlight key challenges, including tumor heterogeneity, poor immune infiltration, and the need for predictive biomarkers. By integrating immunotherapy with chemotherapy, radiotherapy, and targeted therapy, emerging approaches seek to improve treatment outcomes. This review provides a comprehensive analysis of the evolving landscape of osteosarcoma immunotherapy, offering insights into future directions and potential breakthroughs. Researchers and clinicians will benefit from understanding these developments, as they pave the way for more effective and personalized therapeutic strategies in osteosarcoma.

Targeting Immune Checkpoint Inhibitors for Non-Small-Cell Lung Cancer: Beyond PD-1/PD-L1 Monoclonal Antibodies

Non-small-cell lung cancer (NSCLC) remains a leading cause of cancer-related mortality worldwide. Immunotherapy targeting the PD-1/PD-L1 axis has revolutionized treatment, providing durable responses in a subset of patients. However, with fewer than 50% of patients achieving significant benefits, there is a critical need to expand therapeutic strategies. This review explores emerging targets in immune checkpoint inhibition beyond PD-1/PD-L1, including CTLA-4, TIGIT, LAG-3, TIM-3, NKG2A, and CD39/CD73. We highlight the biological basis of CD8 T cell exhaustion in shaping the antitumor immune response. Novel therapeutic approaches targeting additional inhibitory receptors (IR) are discussed, with a focus on their distinct mechanisms of action and combinatory potential with existing therapies. Despite significant advancements, challenges remain in overcoming resistance mechanisms and optimizing patient selection. This review underscores the importance of dual checkpoint blockade and innovative bispecific antibody engineering to maximize therapeutic outcomes for NSCLC patients.

Antigen-presenting cancer associated fibroblasts enhance antitumor immunity and predict immunotherapy response

Cancer-associated fibroblasts (CAF) play a crucial role in tumor progression and immune regulation. However, the functional heterogeneity of CAFs remains unclear. Here, we identify antigen-presenting CAFs (apCAF), characterized by high MHC II expression, in gastric cancer (GC) tumors and find that apCAFs are preferentially located near tertiary lymphoid structures. Both in vivo and in vitro experiments demonstrate that apCAFs promote T cell activation and enhances its cytotoxic and proliferative capacities, thereby strengthening T cell-mediated anti-tumor immunity. Additionally, apCAFs facilitate the polarization of macrophages toward a pro-inflammatory phenotype. These polarized macrophages, in turn, promote the formation of apCAFs, creating a positive feedback loop that amplifies anti-tumor immune responses. Notably, baseline tumors in immunotherapy responders across various cancer types exhibit higher levels of apCAFs infiltration. This study advances the understanding of CAFs heterogeneity in GC and highlights apCAFs as a potential biomarker for predicting immunotherapy response in pan-cancer.

Biological and clinical significance of tumour-infiltrating lymphocytes in the era of immunotherapy: a multidimensional approach

Immune-checkpoint inhibitors (ICIs) have improved clinical outcomes across several solid tumour types. Prominent efforts have focused on understanding the anticancer mechanisms of these agents, identifying biomarkers of response and uncovering resistance mechanisms to develop new immunotherapeutic approaches. This research has underscored the crucial roles of the tumour microenvironment and, particularly, tumour-infiltrating lymphocytes (TILs) in immune-mediated tumour elimination. Numerous studies have evaluated the prognostic and predictive value of TILs and the mechanisms that govern T cell dysfunction, fuelled by technical developments in single-cell transcriptomics, proteomics, high-dimensional spatial platforms and advanced computational models. However, questions remain regarding the definition of TILs, optimal strategies to study them, specific roles of different TIL subpopulations and their clinical implications in different treatment contexts. Additionally, most studies have focused on the abundance of major TIL subpopulations but have not developed standardized quantification strategies or analysed other crucial aspects such as their functional profile, spatial distribution and/or arrangement, tumour antigen-reactivity, clonal diversity and heterogeneity. In this Review, we discuss a conceptual framework for the systematic study of TILs and summarize the evidence regarding their biological properties and biomarker potential for ICI therapy. We also highlight opportunities, challenges and strategies to support future developments in this field.

LAG Time in the Era of Immunotherapy-New Molecular Insights Into the Immunosuppression Mechanism of Lymphocyte Activation Gene-3

The immune checkpoint receptor lymphocyte activation gene-3 (LAG3) inhibits T-cell activation and was recently validated as a target for cancer immunotherapy. Despite its emergence as a therapeutic target, a lack of molecular-level insight has obscured our understanding of the LAG3 immunosuppression mechanism. This review highlights a series of breakthroughs that have illuminated fundamental aspects of LAG3 molecular biology. Key discoveries include structural insights into LAG3 interactions with ligands and antibodies, mechanistic studies of LAG3 interference with T-cell receptor (TCR) signaling, and the development of novel therapeutics. A particular focus is placed on structure-function relationships for LAG3-targeting drugs, as it has become apparent that several distinct approaches to LAG3 antagonism are viable. In addition to LAG3 antagonists, agonistic LAG3 antibodies and immunostimulatory LAG3 extracellular domains (ECDs) are discussed in the context of current structural and mechanistic data. Collectively, these findings should provide an updated landscape for the design of optimal LAG3-based therapeutics for cancer and autoimmune diseases.

The prognostic significance of epoxide hydrolases in colorectal cancer

Colorectal cancer (CRC) is a common malignant cancer. Epoxide hydrolases (EHs) are involved in the development of cancer by regulating epoxides, but their relationship with CRC is unclear. We used multiple datasets to confirm the expression of different EPHX family members in CRC tissues, and to explore their association with different clinicopathologic characteristics. The Kaplan-Meier method, correlation analysis and random forest algorithm were used to evaluate the prognostic value of EPHX family members for CRC. Finally, the cell experiment verified function of EPHX4 in CRC. The expressions of EPHX1 and EPHX2 were significantly decreased, while those of EPHX3 and EPHX4 were significantly increased in CRC. The expressions of EPHX family members were correlated with some clinicopathologic features and overall survival. The expressions of the EPHX family were positively associated with CD274, CTLA4, HAVCR2, and TIGIT. EPHX2 and EPHX4 were diagnostic and predictive biomarkers for CRC. EPHX4 promoted the malignant phenotype of CRC cells. Our study firstly elucidated the prognostic significance of EPHX family members in CRC and identified novel diagnostic and prognostic biomarkers for CRC.

Bone Marrow CD8 + Abundance Inversely Correlates with Progressive Marrow Fibrosis and Myelodysplastic Evolution in GATA2 Deficiency: Case Report

PURPOSE

GATA2 deficiency, a rare inborn error of immunity, presents with highly variable phenotypes. Bone marrow (BM) changes such as hypocellularity and myelodysplastic syndrome (MDS) are common, with hematopoietic stem cell transplantation being the only curative option due to the risk of progression to acute myeloid leukemia. Although traditional markers like cytogenetic abnormalities and somatic mutations (e.g., ASXL1) identify the risk of leukemic transformation, efforts to identify novel predictors of disease evolution are needed. CD8+ T cells are known to play a key role in MDS immune surveillance, but their specific involvement in GATA2 deficiency remains poorly defined.

METHODS

In this case report, we report on a young adult with GATA2 deficiency who underwent longitudinal monitoring of both peripheral and BM lymphocyte subsets, with a focus on CD8+ T-cell evolution in relation to MDS progression.

RESULTS

The patient exhibited typical GATA2-deficient immune-hematological findings, including monocytopenia, B- and NK-cell deficiency, but had no history of severe infections and remained transfusion-independent. While peripheral CD8+ T-cell levels remained stable over time, a notable reduction in BM CD8+ T cells was observed in association with MDS progression.

CONCLUSION

Providing a long-term follow-up of one GATA2-deficient patient, we suggest that a decrease in BM CD8+ T cells may serve as an early marker of immune surveillance escape and disease progression. These findings underscore the need for further investigation into the role of BM CD8+ T cells in GATA2 deficiency and MDS evolution, potentially offering new insights for follow-up and therapeutic intervention.

Coordinated macrophage and T cell interactions mediate response to checkpoint blockade in colorectal cancer

Mismatch repair deficiency (MMRd), either due to inherited or somatic mutation, is prevalent in colorectal cancer (CRC) and other cancers. While anti-PD-1 therapy is utilized in both local and advanced disease, up to 50% of MMRd CRC fail to respond. Using animal and human models of MMRd, we determined that interactions between MHC+ C1Q+ CXCL9+ macrophages and TCF+ BHLHE40+ PRF1+ T cell subsets are associated with control of MMRd tumor growth, during anti-PD-1 treatment. In contrast, resistance is associated with upregulation of TIM3, LAG3, TIGIT, and PD-1 expression on T cells, and infiltration of the tumor with immunosuppressive TREM2+ macrophages and monocytes. By combining anti-PD-1 with anti-LAG3/CTLA4/TREM2, up to 100% tumor eradication was achieved in MMRd CRC and remarkably, in >70% in MMRp CRC. This study identifies key T cell and macrophage subsets mediating the efficacy of immunotherapy in overcoming immune escape in both MMRd and MMRp CRC settings.

Abstract Figure

Highlights

Anti-PD-1 therapy leads to the accumulation and colocalization of MHCI/II+ C1Q+ CXCL9+ macrophages and DCs with TCF+ CCL5+ T cells that have high TCR diversity.Resistance to anti-PD-1 therapy involves multiple T cell checkpoints, TREM2+ macrophages, IL1B+ TREM1+ monocytes and neutrophils, and IFITM+ tumor cells.Simultaneous blockade of PD-1, LAG3, CTLA-4 and TREM2 dramatically prevents progression of both MMRd and MMRp tumors.Combination therapy completely eliminates tumors by leveraging MHC+ macrophage, CD4+ and CD8+ T cell interactions, facilitating durable anti-tumor effects.

Anti-LAG-3 antibody LBL-007 plus anti-PD-1 antibody toripalimab in advanced nasopharyngeal carcinoma and other solid tumors: an open-label, multicenter, phase Ib/II trial

PURPOSE

Open-label phase Ib/II study to investigate the safety and efficacy of LBL-007, an anti-LAG-3 antibody, plus toripalimab, an anti-PD-1 antibody, in patients with previously treated advanced nasopharyngeal carcinoma (NPC) and other solid tumors.

METHODS

Patients with advanced tumors refractory to prior standard therapies were enrolled. In phase Ib, patients received LBL-007 200 mg or 400 mg and toripalimab 240 mg intravenously once every 3 weeks. In phase II, all patients received LBL-007 at the recommended phase II dose (RP2D) and toripalimab 240 mg intravenously once every 3 weeks. The primary end points were safety in phase Ib and objective response rate (ORR) in phase II. The exploratory end point was the predictive capability of LAG-3 and PD-L1 expression for efficacy.

RESULTS

Between November 30, 2021, and December 1, 2023, 80 patients were enrolled, including 30 (37.5%) with NPC and 50 (62.5%) with other tumors. Median follow-up was 26.0 months. In Phase Ib, LBL-007 was administered at 200 mg to four patients and 400 mg to six patients, with no dose-limiting toxicities observed. Therefore, the 400 mg dose of LBL-007 was established as the RP2D and administered to 70 patients in phase II. Nine (11.3%) of 80 patients had grade 3 or 4 treatment-related adverse events, the most common of which included anemia (2.5%), hyponatremia (2.5%), increased alanine aminotransferase (2.5%), increased aspartate aminotransferase (1.3%), and fatigue (1.3%). Eight patients (10.0%) had treatment-related serious adverse events. No treatment-related deaths were reported. In immunotherapy-naive NPC patients (n = 12), ORR was 33.3%, disease control rate (DCR) was 75%, and median progression-free survival (PFS) was 10.8 months (95% CI, 1.3 to not estimated). In IO-treated NPC patients (n = 17), ORR was 11.8%, DCR was 64.7%, and median PFS was 2.7 months (95% CI, 1.4 to 4.9). For other tumors, ORRs were 15.8% in immunotherapy-naive patients and 3.7% in immunotherapy-treated patients. Patients with ≥ 2 + LAG-3 expression had a higher ORR of 28.0%, compared to 7.7% in those with < 2 + LAG-3 expression.

CONCLUSION

LBL-007 plus toripalimab exhibited a manageable safety profile in patients with advanced solid tumors and demonstrated promising antitumor activity in NPC, especially in immunotherapy-naive patients. These findings warrant further validation in future studies.

High Extracellular K+ Skews T-Cell Differentiation Towards Tumour Promoting Th2 and Treg Subsets

Potassium ions (K+) released from dying necrotic tumour cells accumulate in the tumour microenvironment (TME) and increase the local K+ concentration to 50 mM (high-[K+]e). Here, we demonstrate that high-[K+]e decreases expression of the T-cell receptor subunits CD3ε and CD3ζ and co-stimulatory receptor CD28 and thereby dysregulates intracellular signal transduction cascades. High-[K+]e also alters the metabolic profiles of T-cells, limiting the metabolism of glucose and glutamine, consistent with functional exhaustion. These changes skew T-cell differentiation, favouring Th2 and iTreg subsets that promote tumour growth while restricting antitumour Th1 and Th17 subsets. Similar phenotypes were noted in T-cells present within the necrosis-prone core versus the outer zones of hepatocellular carcinoma (HCC)/colorectal carcinoma (CRC) tumours as analysed by GeoMx digital spatial profiling and flow-cytometry. Our results thus expand the understanding of the contribution of high-[K+]e to the immunosuppressive milieu in the TME.

Disulfidptosis as a key regulator of glioblastoma progression and immune cell impairment

Background

Glioblastoma, associated with poor prognosis and impaired immune function, shows potential interactions between newly identified disulfidptosis mechanisms and T cell exhaustion, yet these remain understudied.

Methods

Key genes were identified using Lasso regression, followed by multivariate analysis to develop a prognostic model. Single-cell pseudotemporal analysis explored disulfidptosis T-cell exhaustion (Tex) signaling in cell differentiation. Immune infiltration was assessed via ssGSEA, while transwell assays and immunofluorescence examined the effects of disulfidptosis-Tex genes on glioma cell behavior and immune response.

Results

Eleven disulfidptosis-Tex genes were found critical for glioblastoma survival outcomes. This gene set underpinned a model predicting patient prognosis. Single-cell analysis showed high disulfidptosis-Tex activity in endothelial cells. Memory T cell populations were linked to these genes. SMC4 inhibition reduced LN299 cell migration and increased chemotherapy sensitivity, decreasing CD4 and CD8 T cell activation.

Conclusions

Disulfidptosis-Tex genes are pivotal in glioblastoma progression and immune interactions, offering new avenues for improving anti-glioblastoma therapies through modulation of T cell exhaustion.

Efficacy of Anti-Cancer Immune Responses Elicited Using Tumor-Targeted IL-2 Cytokine and Its Derivatives in Combined Preclinical Therapies

Effective cancer therapies must address the tumor microenvironment (TME), a complex network of tumor cells and stromal components, including endothelial, immune, and mesenchymal cells. Durable outcomes require targeting both tumor cells and the TME while minimizing systemic toxicity. Interleukin-2 (IL-2)-based therapies have shown efficacy in cancers such as metastatic melanoma and renal cell carcinoma but are limited by severe side effects. Innovative IL-2-based immunotherapeutic approaches include immunotoxins, such as antibody-drug conjugates, immunocytokines, and antibody-cytokine fusion proteins that enhance tumor-specific delivery. These strategies activate cytotoxic CD8+ T lymphocytes and natural killer (NK) cells, eliciting a potent Th1-mediated anti-tumor response. Modified IL-2 variants with reduced Treg cell activity further improve specificity and reduce immunosuppression. Additionally, IL-2 conjugates with peptides or anti-angiogenic agents offer improved therapeutic profiles. Combining IL-2-based therapies with immune checkpoint inhibitors (ICIs), anti-angiogenic agents, or radiotherapy has demonstrated synergistic potential. Preclinical and clinical studies highlight reduced toxicity and enhanced anti-tumor efficacy, overcoming TME-driven immune suppression. These approaches mitigate the limitations of high-dose soluble IL-2 therapy, promoting immune activation and minimizing adverse effects. This review critically explores advances in IL-2-based therapies, focusing on immunotoxins, immunocytokines, and IL-2 derivatives. Emphasis is placed on their role in combination strategies, showcasing their potential to target the TME and improve clinical outcomes effectively. Also, the use of IL-2 immunocytokines in "in situ" vaccination to relieve the immunosuppression of the TME is discussed.

New insight in immunotherapy and combine therapy in colorectal cancer

The advent of immune checkpoint inhibitors (ICIs) in colorectal cancer (CRC) treatment marks a major breakthrough. These therapies have proven safer and more effective than traditional radiotherapy and targeted treatments. Immunotherapies like pembrolizumab, nivolumab, and ipilimumab have pioneered new treatment avenues, potentially improving patient outcomes and quality of life. Additionally, advances in immunotherapy have prompted detailed research into CRC therapies, especially those integrating ICIs with conventional treatments, providing new hope for patients and shaping future research and practice. This review delves into the mechanisms of various ICIs and evaluates their therapeutic potential when combined with radiotherapy, chemotherapy, and targeted therapies in clinical settings. It also sheds light on the current application and research involving ICIs in CRC treatment.

Advances in LAG3 cancer immunotherapeutics

Cancer treatment has entered the age of immunotherapy. Immune checkpoint inhibitor (ICI) therapy has shown robust therapeutic potential in clinical practice, with significant improvements in progression-free survival (PFS) and overall survival (OS). Recently, checkpoint blockade of the lymphocyte activation gene 3 (LAG3) inhibitory receptor (IR) in combination with programmed death protein 1 (PD1) inhibition has been FDA approved in patients with advanced melanoma. This has encouraged the clinical evaluation of new LAG3-directed biologics in combination with other checkpoint inhibitors. Several of these studies are evaluating bispecific antibodies that target exhausted T (TEX) cells expressing multiple IRs. This review discusses the current understanding of LAG3 in regulating antitumor immunity and the ongoing clinical testing of LAG3 inhibition in cancer.

Dual inhibition of LAG-3 and PD-1 with IBI110 and sintilimab in advanced solid tumors: the first-in-human phase Ia/Ib study

BACKGROUND

Co-inhibition of immune checkpoints lymphocyte-activation gene 3 (LAG-3) and PD-1 is believed to enhance cancer immunotherapy through synergistic effects. Herein, we evaluate the safety and efficacy of IBI110 (anti-LAG-3 antibody) with sintilimab (an anti-PD-1 antibody) in Chinese patients with advanced solid tumors.

METHODS

In this open-label phase I study, phase Ia dose escalation of IBI110 monotherapy and phase Ib combination dose escalation of IBI110 plus sintilimab were conducted in patients with advanced solid tumors. Additionally, phase Ib combination dose expansion of IBI110 plus sintilimab and chemotherapy was conducted in previously untreated, advanced squamous non-small cell lung cancer (sqNSCLC) and HER-2 negative gastric cancer (GC). In phase Ia dose escalation, patients received IBI110 monotherapy at 0.01/0.1/0.3/1/3/10/20 mg/kg Q3W. In phase Ib dose escalation, patients received IBI110 at 0.3/0.7/1.5/3/5/8/10 mg/kg Q3W plus sintilimab 200 mg Q3W. In phase Ib combination dose expansion, patients received IBI110 at recommended phase 2 dose (RP2D) plus sintilimab 200 mg Q3W and chemotherapy. The primary endpoints were safety, tolerability and efficacy including objective response rate (ORR), disease control rate (DCR), duration of response (DoR), progression-free survival (PFS) assessed by RECIST v1.1 and overall survival (OS). The secondary endpoints included pharmacokinetics, pharmacodynamics and immunogenicity.

RESULTS

In phase Ia dose escalation (n = 28), treatment-related adverse events (TRAEs) occurred in 67.9% patients and grade ≥ 3 TRAEs occurred in 21.4% patients. In phase Ib combination dose escalation (n = 45), TRAEs occurred in 75.6% patients and grade ≥ 3 TRAEs occurred in 22.2% patients. No dose-limiting toxicity (DLT) was observed. The most common TRAE was anemia (17.9%, including 3.6% ≥ G3) in phase Ia dose escalation of IBI110 monotherapy (n = 28), aspartate aminotransferase increased (28.9%, all G1-G2) in phase Ib dose escalation of IBI110 plus sintilimab (n = 45), anemia (70.0%, all G1-G2) in phase Ib dose expansion in sqNSCLC (n = 20), and neutrophil count decreased (64.7%, including 17.6%≥ G3) in phase Ib dose expansion in GC (n = 17). The RP2D of IBI110 was determined at 200 mg (3 mg/kg) Q3W. ORR in phase Ia/Ib dose escalation was 3.6% with IBI110 monotherapy and 14% with IBI110 plus sintilimab. In phase Ib combination dose expansion of IBI110 plus sintilimab and chemotherapy, unconfirmed and confirmed ORR in sqNSCLC (n = 20) was 80.0% (95% CI, 56.3-94.3) and 75.0% (95% CI, 50.9-91.3), respectively and in GC (n = 17) was 88.2% (95% CI, 63.6-98.5) and 70.6% (95% CI, 44.0-89.7), respectively.

CONCLUSIONS

IBI110 monotherapy and in combination with sintilimab were well-tolerated in Chinese patients with advanced solid tumors. Encouraging efficacy of IBI110 in combination with sintilimab and chemotherapies was observed in sqNSCLC and GC.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04085185.

Current trends in sensitizing immune checkpoint inhibitors for cancer treatment

Immune checkpoint inhibitors (ICIs) have dramatically transformed the treatment landscape for various malignancies, achieving notable clinical outcomes across a wide range of indications. Despite these advances, resistance to immune checkpoint blockade (ICB) remains a critical clinical challenge, characterized by variable response rates and non-durable benefits. However, growing research into the complex intrinsic and extrinsic characteristics of tumors has advanced our understanding of the mechanisms behind ICI resistance, potentially improving treatment outcomes. Additionally, robust predictive biomarkers are crucial for optimizing patient selection and maximizing the efficacy of ICBs. Recent studies have emphasized that multiple rational combination strategies can overcome immune checkpoint resistance and enhance susceptibility to ICIs. These findings not only deepen our understanding of tumor biology but also reveal the unique mechanisms of action of sensitizing agents, extending clinical benefits in cancer immunotherapy. In this review, we will explore the underlying biology of ICIs, discuss the significance of the tumor immune microenvironment (TIME) and clinical predictive biomarkers, analyze the current mechanisms of resistance, and outline alternative combination strategies to enhance the effectiveness of ICIs, including personalized strategies for sensitizing tumors to ICIs.

Siglec-G Suppresses CD8+ T Cells Responses through Metabolic Rewiring and Can be Targeted to Enhance Tumor Immunotherapy

CD8+ T cells play a critical role in cancer immune-surveillance and pathogen elimination. However, their effector function can be severely impaired by inhibitory receptors such as programmed death-1 (PD-1) and T cell immunoglobulin domain and mucin domain-3 (Tim-3). Here Siglec-G is identified as a coinhibitory receptor that limits CD8+ T cell function. Siglec-G is highly expressed on tumor-infiltrating T cells and is enriched in the exhausted T cell subset. Ablation of Siglec-G enhances the efficacy of adoptively transferred T cells and chimeric antigen receptor (CAR) T cells in suppressing solid tumors growth. Mechanistically, sialoglycan ligands, such as CD24 on tumor cells, activate the Siglec-G-SHP2 axis in CD8+ T cells, impairing metabolic reprogramming from oxidative phosphorylation to glycolysis, which dampens cytotoxic T lymphocyte (CTL) activation, expansion, and cytotoxicity. These findings discover a critical role for Siglec-G in inhibiting CD8+ T cell responses, suggesting its potential therapeutic effect in adoptive T cell therapy and tumor immunotherapy.

Next-generation combination approaches for immune checkpoint therapy

Immune checkpoint therapy has revolutionized cancer treatment, leading to dramatic clinical outcomes for a subset of patients. However, many patients do not experience durable responses following immune checkpoint therapy owing to multiple resistance mechanisms, highlighting the need for effective combination strategies that target these resistance pathways and improve clinical responses. The development of combination strategies based on an understanding of the complex biology that regulates human antitumor immune responses has been a major challenge. In this Review, we describe the current landscape of combination therapies. We also discuss how the development of effective combination strategies will require the integration of small, tissue-rich clinical trials, to determine how therapy-driven perturbation of the human immune system affects downstream biological responses and eventual clinical outcomes, reverse translation of clinical observations to immunocompetent preclinical models, to interrogate specific biological pathways and their impact on antitumor immune responses, and novel computational methods and machine learning, to integrate multiple datasets across clinical and preclinical studies for the identification of the most relevant pathways that need to be targeted for successful combination strategies.

Lymphocyte-activation gene 3 in cancer immunotherapy: function, prognostic biomarker and therapeutic potentials

Lymphocyte-activation gene 3 (LAG-3) has emerged as a key immune checkpoint regulating immune responses in the context of cancer. The inhibitory effect of LAG-3-expressing T cells contributes to suppressing anti-tumor immunity and promoting tumor progression. This review discusses the function of LAG-3 in immune suppression, its interactions with ligands, and its potential as a prognostic biomarker for cancers. We also explore therapeutic strategies targeting LAG-3, including monoclonal antibodies, small molecule inhibitors, and CAR T cells. This review summarizes the current preclinical and clinical studies on LAG-3, highlighting the potential of therapeutic regimens targeting LAG-3 to enhance antitumor immunity and improve patients' outcomes. Further studies are needed to fully elucidate the mechanism of action of LAG-3 and optimize its application in tumor therapy.

LAGging behind no more: PD-1 has a new immunotherapy partner

PD-1 blockade partially reverses T cell exhaustion in cancer patients, but broad responses are still limited. Three studies recently published in Cell illuminate how abrogating LAG-3 and PD-1 synergize to further push effector T cell functionality via distinct molecular mechanisms.

Immune Checkpoint Inhibitor Therapy for Metastatic Melanoma: What Should We Focus on to Improve the Clinical Outcomes?

Immune checkpoint inhibitors (ICIs) have transformed cancer treatment by enhancing anti-tumour immune responses, demonstrating significant efficacy in various malignancies, including melanoma. However, over 50% of patients experience limited or no response to ICI therapy. Resistance to ICIs is influenced by a complex interplay of tumour intrinsic and extrinsic factors. This review summarizes current ICIs for melanoma and the factors involved in resistance to the treatment. We also discuss emerging evidence that the microbiota can impact ICI treatment outcomes by modulating tumour biology and anti-tumour immune function. Furthermore, microbiota profiles may offer a non-invasive method for predicting ICI response. Therefore, future research into microbiota manipulation could provide cost-effective strategies to enhance ICI efficacy and improve outcomes for melanoma patients.

Mechanistic Insights into the Successful Development of Combination Therapy of Enfortumab Vedotin and Pembrolizumab for the Treatment of Locally Advanced or Metastatic Urothelial Cancer

Antibody-drug conjugates (ADCs) consist of an antibody backbone that recognizes and binds to a target antigen expressed on tumor cells and a small molecule chemotherapy payload that is conjugated to the antibody via a linker. ADCs are one of the most promising therapeutic modalities for the treatment of various cancers. However, many patients have developed resistance to this form of therapy. Extensive efforts have been dedicated to identifying an effective combination of ADCs with other types of anticancer therapies to potentially overcome this resistance. A recent clinical study demonstrated that a combination of the ADC enfortumab vedotin (EV) with the immune checkpoint inhibitor (ICI) pembrolizumab can achieve remarkable clinical efficacy as the first-line therapy for the treatment of locally advanced or metastatic urothelial carcinoma (la/mUC)-leading to the first approval of a combination therapy of an ADC with an ICI for the treatment of cancer patients. In this review, we highlight knowledge and understanding gained from the successful development of EV and the combination therapy of EV with ICI for the treatment of la/mUC. Using urothelial carcinoma as an example, we will focus on dissecting the underlying mechanisms necessary for the development of this type of combination therapy for a variety of cancers.

LAG-3 and PD-1 synergize on CD8+ T cells to drive T cell exhaustion and hinder autocrine IFN-γ-dependent anti-tumor immunity

Overcoming immune-mediated resistance to PD-1 blockade remains a major clinical challenge. Enhanced efficacy has been demonstrated in melanoma patients with combined nivolumab (anti-PD-1) and relatlimab (anti-LAG-3) treatment, the first in its class to be FDA approved. However, how these two inhibitory receptors synergize to hinder anti-tumor immunity remains unknown. Here, we show that CD8+ T cells deficient in both PD-1 and LAG-3, in contrast to CD8+ T cells lacking either receptor, mediate enhanced tumor clearance and long-term survival in mouse models of melanoma. PD-1- and LAG-3-deficient CD8+ T cells were transcriptionally distinct, with broad TCR clonality and enrichment of effector-like and interferon-responsive genes, resulting in enhanced IFN-γ release indicative of functionality. LAG-3 and PD-1 combined to drive T cell exhaustion, playing a dominant role in modulating TOX expression. Mechanistically, autocrine, cell-intrinsic IFN-γ signaling was required for PD-1- and LAG-3-deficient CD8+ T cells to enhance anti-tumor immunity, providing insight into how combinatorial targeting of LAG-3 and PD-1 enhances efficacy.

Anti-LAG-3 boosts CD8 T cell effector function

LAG-3 is the third immune checkpoint pathway successfully targeted for cancer therapy. Although ineffective as a monotherapy, combination of LAG-3 and PD-1 blockade improves survival from advanced melanoma. In this issue of Cell, two studies in mice and a human clinical trial provide insights on LAG-3 in immune regulation.

LAG-3 sustains TOX expression and regulates the CD94/NKG2-Qa-1b axis to govern exhausted CD8 T cell NK receptor expression and cytotoxicity

Exhausted CD8 T (Tex) cells in chronic viral infection and cancer have sustained co-expression of inhibitory receptors (IRs). Tex cells can be reinvigorated by blocking IRs, such as PD-1, but synergistic reinvigoration and enhanced disease control can be achieved by co-targeting multiple IRs including PD-1 and LAG-3. To dissect the molecular changes intrinsic when these IR pathways are disrupted, we investigated the impact of loss of PD-1 and/or LAG-3 on Tex cells during chronic infection. These analyses revealed distinct roles of PD-1 and LAG-3 in regulating Tex cell proliferation and effector functions, respectively. Moreover, these studies identified an essential role for LAG-3 in sustaining TOX and Tex cell durability as well as a LAG-3-dependent circuit that generated a CD94/NKG2+ subset of Tex cells with enhanced cytotoxicity mediated by recognition of the stress ligand Qa-1b, with similar observations in humans. These analyses disentangle the non-redundant mechanisms of PD-1 and LAG-3 and their synergy in regulating Tex cells.