Intratumoral Tcf1+PD-1+CD8+ T Cells with Stem-like Properties Promote Tumor Control in Response to Vaccination and Checkpoint Blockade Immunotherapy

Lymphatic chain gradients regulate the magnitude and heterogeneity of T cell responses to vaccination

Upon activation, T cells proliferate and differentiate into diverse populations, including highly differentiated effector and memory precursor subsets. Initial diversification is influenced by signals sensed during T cell priming within lymphoid tissues. However, the rules governing how cellular heterogeneity is spatially encoded in vivo remain unclear. Here, we show that immunization establishes concentration gradients of antigens and inflammation across interconnected chains of draining lymph nodes (IC-LNs). While T cells are activated at all sites, individual IC-LNs elicit divergent responses: proximal IC-LNs favor the generation of effector cells, whereas distal IC-LNs promote formation of central memory precursor cells. Although both proximal and distal sites contribute to anamnestic responses, T cells from proximal IC-LNs preferentially provide early effector responses at inflamed tissues. Conversely, T cells from distal IC-LNs demonstrate an enhanced capacity to generate long-lasting responses to chronic antigens in cancer settings, including after checkpoint blockade therapy. Therefore, formation of spatial gradients across lymphatic chains following vaccination regulates the magnitude, heterogeneity, and longevity of T cell responses.

Transient inhibition of type I interferon enhances CD8+ T cell stemness and vaccine protection

Developing vaccines that promote CD8+ T cell memory is a challenge for infectious disease and cancer immunotherapy. TCF-1+ stem cell-like memory CD8+ T (TSCM) cells are important determinants of long-lived memory. Yet, the developmental requirements for TSCM cell formation are unclear. Here, we identify the temporal window for type I interferon receptor (IFNAR) blockade to drive TSCM cell generation following viral infection and mRNA-lipid nanoparticle vaccination. We reveal a reversible developmental trajectory where transcriptionally distinct TSCM cells emerged from a transitional precursor of exhausted T cellular state concomitant with viral clearance. TSCM cell differentiation correlated with T cell retention within the lymph node paracortex due to disrupted CXCR3 chemokine gradient formation. These effects were linked to increased antigen load and a counterintuitive increase in IFNγ, which controlled cell location. Vaccination with the IFNAR blockade promoted TSCM cell differentiation and enhanced protection against chronic infection. These findings propose an approach to vaccine design whereby modulation of inflammation promotes memory formation and function.

Cholinergic T cells revitalize the tumor immune microenvironment: TIME to ChAT

Crosstalk between the nervous system and the immune system shapes the tumor microenvironment. Cholinergic T cells, a unique population of T cell antigen receptor-induced acetylcholine-producing T cells, have emerged as an integrative interface between these two fundamental body systems. Here we review the distinct characteristics and functions of cholinergic T cells in cancer settings. We first outline the expression of choline acetyltransferase and the cholinergic machinery in T cells. We then describe the dysfunctional state of choline acetyltransferase-expressing T cells in cancer and delve into their modulatory effects on T cells, cancer cells and the tumor microenvironment, including its populations of immune cells, its vasculature and its nerves. We also discuss the clinical implications of harnessing the potential of cholinergic T cells and future directions for increasing our understanding of their importance and possible exploitation.

DNA methylation in melanoma immunotherapy: mechanisms and therapeutic opportunities

Abnormal DNA methylation is a hallmark of cancer and a nearly universal feature of melanoma. DNA methylation plays well-appreciated melanoma cell-intrinsic roles, including silencing tumor-suppressor genes, regulating genomic stability, deregulating expression of oncogenes to potentiate proliferative signaling and tumor migration. With the recent success of immunological therapies for melanoma, important roles for DNA methylation are also emerging at the interface between melanoma and immune cells with the potential to regulate the anti-tumor immune response. These newly recognized roles for DNA methylation in controlling melanoma cell immunogenicity, expression of MHC and immune checkpoint molecules as well as T cell phenotypes in the tumor microenvironment raise the possibility of using DNA methylation to develop improved therapies and methylation-based biomarkers. In addition to reviewing the "immune dimension" of DNA methylation, we summarize recent developments with potential clinical applications in melanoma, such as targeted DNA methylation editing, single-cell methylation approaches, and measurement of circulating methylated DNA. An improved understanding of the immune roles of DNA methylation presents an exciting opportunity for continued improvement of care and outcomes for patients with melanoma.

Reprogramming of radiation-deteriorated TME by liposomal nanomedicine to potentiate radio-immunotherapy

Radiotherapy, although widely used for cancer therapy, always triggers changes in tumor microenvironment (TME) that lead to radioresistance and immunosuppression. In particular, during X-ray irradiation, hypoxia exacerbation would reduce radiosensitivity of tumor cells, while programmed cell death ligand 1 (PD-L1) upregulation impairs antitumor immune responses and exacerbates DNA damage repair, collectively resulting in severe T cell exhaustion and unsatisfactory therapeutic effect. Herein, we developed a liposomal nanodrug, C/J-LipoRGD, to simultaneously encapsulate a biological enzyme and a bromodomain containing 4 (BRD4) inhibitor for tumor-targeting delivery and TME modulation. Among C/J-LipoRGD, catalase could catalyze the decomposition of the excess H2O2 in tumors and improve TME oxygenation. Meanwhile, JQ1 as a BRD4 inhibitor after being taken by cancer cells could downregulate PD-L1 expression in both cellular membrane and cytosol, inhibiting PD-1/PD-L1 interaction and DNA damage repair. By alleviating hypoxia and downregulating PD-L1 expression, C/J-LipoRGD reverses T cell exhaustion in TME. Altogether, C/J-LipoRGD-based radiotherapy significantly inhibited tumor growth and meanwhile triggered immunogenic cell death (ICD) of cancer cells to activate T cell-mediated anti-tumor immunity. After the combination with αPD-1, C/J-LipoRGD-based radio-immunotherapy achieved complete tumor eradication and metastases elimination in 80 % mice with survival over 80 days. This multifunctional nanodrug represents a promising strategy to overcome therapy resistance and optimize radio-immunotherapy outcomes.

Tumor-infiltrated double-negative regulatory T cells predict outcome of T cell-based immunotherapy in nasopharyngeal carcinoma

Adoptive cell therapy (ACT) using tumor-infiltrating lymphocytes (TILs) has demonstrated clinical success in solid tumors. We analyze 47 TIL infusion products and 62 pretreatment tumor microenvironments (TMEs) from a randomized phase 2 clinical study of concurrent chemoradiotherapy plus TIL-ACT (NCT02421640). Using single-cell and bulk RNA sequencing along with flow cytometry, we identify 14 CD3+ T cell clusters within 26 TIL infusion products: 11 CD3+CD8+ TILs, 2 CD3+CD4+ TILs, and 1 CD3+CD8-CD4- double-negative (DN) TIL. (DN) TILs, significantly associated with poor TIL-ACT outcomes, exhibit an activated regulatory T cell-like phenotype and include two CD56+ and four CD56- subsets. Among them, CD56-KZF2+ (DN) TILs are predominantly suppressive. (DN) TILs inhibit CD8+ TIL expansion via Fas-FasL, transforming growth factor β (TGF-β), and interleukin (IL)-10 signaling. Distinct CD8+ T subsets differentially impact on TIL-ACT outcomes, while 9 baseline TME gene signatures and 14 intracellular T cell genes hold prognostic value. Our findings identify predictive TIL subsets and biomarkers for TIL-ACT outcomes.

Spatial analysis identifies DC niches as predictors of pembrolizumab therapy in head and neck squamous cell cancer

Head and neck squamous cell carcinoma (HNSCC) shows variable response to anti-programmed cell death protein 1 (PD-1) therapy, which can be partially explained by a combined positive score (CPS) of tumor and immune cell expression of programmed death-ligand 1 (PD-L1) within the local tumor microenvironment (TME). To better define TME immune determinants associated with treatment efficacy, we conduct a study of n = 48 HNSCC tumors from patients prior to pembrolizumab therapy. Our investigation combines a rapid bioorthogonal multiplex staining method with computational analysis of whole-slide imaging to capture the single-cell spatial heterogeneity and complexity of the TME. Analyzing 6,316 fields of view (FOVs), we provide comprehensive PD-L1 phenotyping and cell proximity assays across the entirety of tissue sections. While none of the PD-L1 metrics adequately predict response, we find that the spatial organization of CCR7+ dendritic cells (DCs) in niches better predicts overall patient survival than CPS alone. This study highlights the importance of understanding the spatial context of immune networks for immunotherapy.

Bone metastases diminish extraosseous response to checkpoint blockade immunotherapy through osteopontin-producing osteoclasts

Bone metastatic lesions typically associate with suboptimal responses to immune checkpoint blockade (ICB) therapies. In this study, we observed that across multiple clinical cohorts and a variety of mouse models, the presence of osseous metastases induces ICB resistance in extraosseous tumors. Mechanistically, this long-distance communication is mediated by osseous tumor-conditioned osteoclasts producing osteopontin (OPN). Through circulation, OPN reprograms the extraosseous tumor microenvironment and impairs T cell recruitment and differentiation of CD8+TCF1+ precursor cells, an essential population for ICB efficacy. In mice, ICB responsiveness is restored by αRANKL blockade of osteoclastogenesis, neutralization of OPN in circulation, or tissue-specific depletion of OPN in osteoclasts. Both the mode of action and therapeutic benefit were validated in clinical cohorts with the αRANKL-ICB combinatory regimen. These findings establish bone as a specific immunoregulatory organ exploited by tumor metastasis and suggest osteoclastogenesis as a promising target to improve ICB prognosis in patients with bone metastasis.

Pre-existing intratumoral stem-like CD8+ T cells drive radiotherapy-induced tumor immunity

CD8+ T cells are crucial for both spontaneous and therapy-induced restriction of tumor progression. Although many patients with cancer undergo radiotherapy, the precise effect of this genotoxic treatment on tumor-associated CD8+ T cells is insufficiently understood. Here, we investigated the influence of radiotherapy on intratumoral CD8+ T cells. We found that, although these CD8+ T cells initially decline following radiotherapy, they subsequently expand and are both essential and sufficient for early tumor control. In response to radiotherapy, stem-like CD8+ T cells proliferate and differentiate into effector CD8+ T cells, making them key drivers of tumor immunity. Our findings underscore the pivotal role of intratumoral stem-like CD8+ T cells in mediating radiotherapy-induced anti-tumor immunity and provide deeper insights into the dynamic behavior of CD8+ T cells during tumor control after radiotherapy.

Quantitatively defined stromal B cell aggregates are associated with response to checkpoint inhibitors in unresectable melanoma

Multiplex immunofluorescence (mIF) is a promising tool for immunotherapy biomarker discovery in melanoma and other solid tumors. mIF captures detailed phenotypic information of immune cells in the tumor microenvironment, as well as spatial data that can reveal biologically relevant interactions among cell types. Given the complexity of mIF data, the development of automated analysis pipelines is crucial for advancing biomarker discovery. In pre-treatment melanoma samples from 50 patients treated with immune checkpoint inhibitors (ICIs), a higher stromal B cell percentage is associated with the clinical benefit of ICI therapy. The automatic detection of B cell aggregates with DBSCAN, a novel application of a computer-aided machine learning algorithm, demonstrates the potential for enhanced accuracy compared to pathologist assessment of lymphoid aggregates. TCF1+ and LAG3- T cell subpopulations are enriched near stromal B cells, suggesting potential functional interactions. These analyses provide a roadmap for the further development of spatial immunotherapy biomarkers in melanoma and other diseases.

Impact of mitochondrial metabolism on T-cell dysfunction in chronic lymphocytic leukemia

T cells play a central role in anti-tumor immunity, yet their function is often compromised within the immunosuppressive tumor microenvironment, leading to cancer progression and resistance to immunotherapies. T-cell activation and differentiation require dynamic metabolic shifts, with mitochondrial metabolism playing a crucial role in sustaining their function. Research in cancer immunometabolism has revealed key mitochondrial abnormalities in tumor-infiltrating lymphocytes, including reduced mitochondrial capacity, depolarization, structural defects, and elevated reactive oxygen species. While these mitochondrial disruptions are well-characterized in solid tumors and linked to T-cell exhaustion, their impact on T-cell immunity in lymphoproliferative disorders remains underexplored. Chronic lymphocytic leukemia (CLL), the most prevalent chronic adult leukemia, is marked by profound T-cell dysfunction that limits the success of adoptive cell therapies. Emerging studies are shedding light on the role of mitochondrial disturbances in CLL-related T-cell dysfunction, but significant knowledge gaps remain. This review explores mitochondrial metabolism in T-cell exhaustion, emphasizing recent findings in CLL. We also discuss therapeutic strategies to restore T-cell mitochondrial function and identify key research gaps.

Shp-1 regulates the activity of low-affinity T cells specific to endogenous self-antigen during melanoma tumor growth and drives resistance to immune checkpoint inhibition

BACKGROUND

The presence of activated CD8 T cells in the tumor microenvironment is correlated with an effective immune response to immune checkpoint inhibitor (ICI) therapy. However, ICI predominantly targets high-affinity T cells, which may be less abundant in tumors with few neoantigens. Targeting the intracellular phosphatase Src homology region 2 domain-containing phosphatase-1 (Shp-1) in combination with ICI lowers the T cell activation threshold and enhances the ability of low-affinity T cells to mount a productive antitumor response.

METHODS

In this study, we sought to determine whether temporal inhibition of Shp-1 during active tumor growth could rescue the activity of low-affinity T cells specific for endogenous self-antigens. To address this question, we implanted Yale University Mouse Melanoma (YUMM) tumor cell lines into WT mice and, on tumor establishment, administered an inhibitor of Shp-1 (TPI-1) with or without ICI treatment. We analyzed treatment-dependent changes in the immune infiltrate in the tumor via flow cytometry, major histocompatibility complex (MHC) tetramer-mediated detection of tyrosinase-related protein 2 (TRP-2)180-188-specific T cells and a micropipette-based two-dimensional affinity assay to measure the T cell receptor (TCR) affinity.

RESULTS

Administration of ICI and a Shp-1 inhibitor to mice with established YUMM tumors, but neither agent alone, resulted in a significant delay in tumor growth and an increased frequency of CD8 tumor-infiltrating T cells with enhanced effector and reduced exhaustion characteristics. In particular, combined treatment increased the frequency of CD8 T cells specific for the MHC Class I-restricted tumor self-antigen TRP-2180-188. We found that the increase in effector T cells was almost entirely due to an increase in T cells with very low TCR affinity.

CONCLUSIONS

We conclude that approaches for altering TCR signaling threshold are effective in enhancing the antitumor response of low-affinity T cells specific for endogenous self-antigens in settings of ICI resistance and/or where neoantigens are not available to drive antitumor responses.

Novel PD-1-targeted, activity-optimized IL-15 mutein SOT201 acting in cis provides antitumor activity superior to PD1-IL2v

BACKGROUND

SOT201 and its murine surrogate mSOT201 are novel cis-acting immunocytokines consisting of a humanized/murinized/, Fc-silenced anti-programmed cell death protein 1 (PD-1) monoclonal antibody (mAb) fused to an attenuated human interleukin (IL)-15 and the IL-15Rα sushi+ domain. Murine mPD1-IL2v is a conjugate of a murinized, Fc silenced anti-PD-1 mAb bearing human IL-2 with abolished IL-2Rα binding. These immunocytokines spatiotemporally reinvigorate PD-1+ CD8+ tumor-infiltrating lymphocytes (TILs) via cis-activation and concomitantly activate the innate immunity via IL-2/15Rβγ signaling.

METHODS

Human peripheral blood mononuclear cell and cell lines were used to evaluate cis/trans activity of SOT201. Anti-PD-1 mAb responsive (MC38, CT26) and resistant (B16F10, CT26 STK11 KO) mouse tumor models were used to determine the anticancer efficacy, and the underlying immune cell activity was analyzed via single-cell RNA sequencing and flow cytometry. The expansion of tumor antigen-specific CD8+ T cells by mSOT201 or mPD1-IL2v and memory CD8+ T-cell generation in vivo was determined by flow cytometry.

RESULTS

SOT201 delivers attenuated IL-15 to PD-1+ T cells via cis-presentation, reinvigorates exhausted human T cells and induces higher interferon-γ production than pembrolizumab in vitro. mSOT201 administered as a single dose exhibits strong antitumor efficacy with several complete responses in all tested mouse tumor models. While mPD1-IL2v activates CD8+ T cells with a 50-fold higher potency than mSOT201 in vitro, mSOT201 more effectively reactivates effector exhausted CD8+ T cells (Tex), which demonstrate higher cytotoxicity, lower exhaustion and lower immune checkpoint transcriptional signatures in comparison to mPD1-IL2v in MC38 tumors in vivo. This can be correlated with a higher rate of complete responses in the MC38 tumor model following mSOT201 treatment when compared with mPD1-IL2v. mSOT201 increased the relative number of tumor antigen-specific CD8+ T cells, and unlike mPD1-IL2v stimulated greater expansion of adoptively transferred ovalbumin-primed CD8+ T cells simultaneously limiting the peripheral CD8+ T-cell sink, leading to the development of memory CD8+ T cells in vivo.

CONCLUSIONS

SOT201 represents a promising therapeutic candidate that preferentially targets PD-1+ TILs, delivering balanced cytokine activity for reviving CD8+ Tex cells in tumors. SOT201 is currently being evaluated in the Phase I clinical study VICTORIA-01 (NCT06163391) in patients with advanced metastatic cancer.

Neoadjuvant immune checkpoint therapy: Enabling insights into fundamental human immunology and clinical benefit

While immune checkpoint therapy (ICT) has revolutionized cancer treatment, most patients with advanced disease fail to achieve durable benefit. To address this challenge, it is essential to integrate mechanistic research with clinical studies to: (1) understand response mechanisms, (2) identify patient-specific resistance pathways, (3) develop biomarkers for patient selection, and (4) design novel therapies to overcome resistance. We propose that incorporating "direct-in-patient" studies into clinical trials is crucial for bridging the gap between fundamental science and clinical oncology. In this review, we first highlight recent clinical success of ICT in the neoadjuvant setting, where treatment is given in earlier disease stages to improve outcomes. We then explore how neoadjuvant clinical trials could be utilized to drive mechanistic laboratory-based investigations. Finally, we discuss novel scientific concepts that will potentially aid in overcoming resistance to ICT, which will require future clinical trials to understand their impact on human immune responses.

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.

Combination radiation and αPD-L1 enhance tumor control by stimulating CD8+ PD-1+ TCF-1+ T cells in the tumor-draining lymph node

Combination radiotherapy (RT) and αPD-L1 therapy has potential to enhance local and distant (abscopal) tumor control, however, clinical results in humans have been variable. Using murine melanoma models, we found RT + αPD-L1 increases intra-tumor progenitor CD8+ PD-1+ TCF-1+ T cells. This increase depends on trafficking of the PD-1+ TCF-1+ cells from the tumor-draining lymph node (TdLN) to the tumor. RT alone promotes the expansion and differentiation of the TdLN derived PD-1+ TCF-1+ cells into TIM-3+ GZMB+ TCF-1- effector-like cells in the tumor with further enhancement after the addition of αPD-L1. In the TdLN, combination therapy enriches for a novel PD-1+ TCF-1+ TOX- LY6A+ subset with expression of a type I interferon and migratory signature. This subset is able to traffic to the tumor and differentiate into TIM-3+ TCF-1- cells. Finally, we found that ablation of the PD-1+ TCF-1+ T cell population attenuates the enhanced tumor control observed with combination RT + αPD-L1. These results suggest that abscopal response failures may be secondary to impaired stimulation of TdLN CD8+ PD-1 + TCF-1+ T cells or an inability of PD-1+ TCF-1+ cells in the TdLN to traffic to the tumor.

A distinct priming phase regulates CD8 T cell immunity by orchestrating paracrine IL-2 signals

T cell priming is characterized by an initial activation phase that involves stable interactions with dendritic cells (DCs). How activated T cells receive the paracrine signals required for their differentiation once they have disengaged from DCs and resumed their migration has been unclear. We identified a distinct priming phase that favors CD8 T cells expressing receptors with high affinity for antigen. CXCR3 expression by CD8 T cells was required for their hours-long reengagement with DCs in specific subfollicular niches in lymph nodes. CD4 T cells paused briefly at the sites of CD8 T cell and DC interactions and provided Interleukin-2 (IL-2) before moving to another DC. Our results highlight a previously unappreciated phase of cell-cell interactions during T cell priming and have direct implications for vaccinations and cellular immunotherapies.

Acasunlimab, an Fc-inert PD-L1×4-1BB bispecific antibody, combined with PD-1 blockade potentiates antitumor immunity via complementary immune modulatory effects

BACKGROUND

Next-generation cancer immunotherapies aim to improve patient outcomes by combining inhibitory signal blockade with targeted T-cell costimulation in tumor and lymphoid tissues. Acasunlimab (DuoBody-PD-L1×4-1BB) is an investigational, bispecific antibody designed to elicit an antitumor immune response via conditional 4-1BB activation strictly dependent on simultaneous programmed death-ligand 1 (PD-L1) binding. Since 4-1BB is coexpressed with programmed cell death protein-1 (PD-1) on CD8+ T cells, PD-1 blockade and simultaneous costimulation through 4-1BB may synergistically enhance T-cell effector functions. We hypothesized that combining acasunlimab with PD-1 blockade to fully disrupt PD-1 interactions with both PD-L1 and PD-L2 would amplify the depth and duration of antitumor immunity.

METHODS

The effect of acasunlimab and pembrolizumab combination was analyzed in vitro using functional immune cell assays, including mixed-lymphocyte reactions and antigen-specific T-cell proliferation and cytotoxicity assays. The antitumor activity of the combination was tested in vivo in (1) MC38, MB49, Pan02, and B16F10 syngeneic tumor models using acasunlimab and anti-PD-1 mouse-surrogate antibodies; and (2) triple knock-in mice expressing the human targets using an acasunlimab chimeric antibody (chi-acasunlimab) and pembrolizumab. The mechanism of action of the combination was investigated in the MC38 syngeneic model through immunohistochemistry, flow cytometry, and bulk RNA sequencing.

RESULTS

The combination reinvigorated dysfunctional T cells in vitro, while also potentiating T-cell expansion, interleukin (IL)-2 and interferon gamma secretion and cytotoxic activity. In vivo, the combination of chi-acasunlimab and pembrolizumab or mouse-surrogate antibodies potentiated antitumor activity and survival in the humanized knock-in and multiple syngeneic mouse models, leading to durable complete tumor regressions in the MC38 model consistent with therapeutic synergy. Mechanistically, the combination enhanced clonal expansion of tumor-specific CD8+ T cells in tumor-draining lymph nodes and increased the density of proliferating and cytotoxic CD8+ T cells in the tumor microenvironment. It also potentiated the IL-2 signaling pathway, increasing the proportion of granzyme B (GZMB+) stem-like CD8+ T cells thought to have superior effector function.

CONCLUSION

These preclinical results demonstrate that conditional 4-1BB stimulation combined with complete PD-1 blockade enhances antitumor immunity through complementary mechanisms. The acasunlimab and pembrolizumab combination is being evaluated in Phase 2 (NCT05117242) and pivotal Phase 3 (NCT06635824) trials in patients with metastatic non-small cell lung cancer after checkpoint inhibitor therapy failure.

GSK-3 regulates CD4-CD8 cooperation needed to generate super-armed CD8+ cytolytic T cells against tumors

While immune checkpoint blockade (ICB) has revolutionized cancer treatment, the key T-cell signaling pathways responsible for its potency remain unclear. GSK-3 is an inhibitory kinase that is most active in resting T-cells. In this study, we demonstrate that GSK-3 facilitates PD-1 blockade, an effect seen by modulating CD4 T-cell help for CD8+ CTL responses against ICB resistant tumors. We show that GSK-3 controls metabolic reprogramming towards glycolysis and synergizes with PD-1 to induce a transcriptional program that reduces suppressive CD4+ Treg numbers while generating super-armed effector-memory CD8+ CTLs that express an unprecedented 7/9 granzymes from the genome. Crucially, we found that GSK-3 cooperates with PD-1 blockade to determine the dependency of CD8+ CTLs on help from CD4+ T-cells. Our study unravels a novel cooperative PD-1 blockade-dependent signaling pathway that potentiates CTL responses against tumors, offering a new strategy to overcome immunotherapy resistance by modulating CD4+ helper and CD8+ cytotoxic functions.

Significance

This study demonstrates for the first time that GSK-3 controls the crosstalk between CD4+ and CD8+ T cells, synergizing with anti-PD-1 therapy to overcome resistance to checkpoint blockade and to generate super-armed CD8+ effector cells in cancer immunotherapy. This newly uncovered GSK-3-dependent CD4-CD8 T-cell crosstalk mechanism presents a new approach to enhance anti-PD-1 immunotherapy.

Tertiary lymphoid structures achieve 'cold' to 'hot' transition by remodeling the cold tumor microenvironment

Immune checkpoint blockade (ICB) therapies have demonstrated significant clinical efficacy in immune-infiltrated tumors such as melanoma and non-small cell lung cancer. However, "cold tumors"-including ovarian cancer, pancreatic cancer, and gliomas-exhibit insufficient immune infiltration, leading to poor therapeutic responses to ICBs and limited improvement in patient prognosis. Recent studies have shown that tumor-associated tertiary lymphoid structures (TLSs) can induce strong local immune responses within the tumor microenvironment (TME), serving as important biological markers for predicting ICB therapy efficacy. Notably, preclinical and clinical studies on cold tumors have confirmed that TLSs can potently enhance ICB efficacy through TME remodeling-a breakthrough that has attracted considerable attention. Here, we systematically examine the immunological profile of cold tumors and decipher the mechanistic basis for their impaired immune cell infiltration. We further delineate the distinctive features of tumor-associated TLSs in generating antitumor immunity and establish criteria for their identification. Significantly, we emphasize the unique capability of TLSs to reprogram the immunosuppressive tumor microenvironment characteristic of cold tumors. Based on these insights, we evaluate clinical evidence supporting TLS-mediated enhancement of ICB efficacy and discuss emerging strategies for exogenous TLSs induction.

Recurrent Composite Markers of Cell Types and States

Biological function is mediated by the hierarchical organization of cell types and states within tissue ecosystems. Identifying interpretable composite marker sets that both define and distinguish hierarchical cell identities is essential for decoding biological complexity, yet remains a major challenge. Here, we present RECOMBINE, an algorithm that identifies recurrent composite marker sets to define hierarchical cell identities. Validation using both simulated and biological datasets demonstrates that RECOMBINE achieves higher accuracy in identifying discriminative markers compared to existing approaches, including differential gene expression analysis. When applied to single-cell data and validated with spatial transcriptomics data from the mouse visual cortex, RECOMBINE identified key cell type markers and generated a robust gene panel for targeted spatial profiling. It also uncovered markers of CD8+; T cell states, including GZMK+;HAVCR2-; effector memory cells associated with anti-PD-1 therapy response, and revealed a rare intestinal subpopulation with composite markers in mice. Finally, using data from the Tabula Sapiens project, RECOMBINE identified composite marker sets across a broad range of human tissues. Together, these results highlight RECOMBINE as a robust, data-driven framework for optimized marker selection, enabling the discovery and validation of hierarchical cell identities across diverse tissue contexts.

Ultrasound-Responsive Nanobubbles for Breast Cancer: Synergistic Sonodynamic, Chemotherapy, and Immune Activation through the cGAS-STING Pathway

Breast cancer remains the leading cause of cancer-related deaths among women worldwide, necessitating more effective treatment strategies. Chemotherapy combined with immunotherapy is the first-line treatment for breast cancer, but it still suffers from limited therapeutic efficiency and serious side effects, which are usually due to the poor delivery efficiency, drug resistance of tumor cells, and immunosuppressive tumor microenvironment. This study explores the development of ultrasound-responsive nanobubbles (Ce6/PTX Nbs) for targeted imaging and sonoimmunotherapy in breast cancer treatment. By integrating sonodynamic therapy (SDT), chemotherapy, and immunotherapy, the nanobubbles aim to address challenges such as poor drug delivery, systemic toxicity, and immune suppression in conventional therapies. The nanobubbles, composed of sonosensitizer chlorin e6 (Ce6)-modified phospholipid and loaded with the chemotherapeutic agent paclitaxel (PTX) enhancing drug-loading capacity, are designed to precisely target tumor sites via cyclic-RGD peptides. Upon ultrasound activation, Ce6 induces reactive oxygen species (ROS), promoting immunogenic cell death (ICD), while PTX disrupts tumor cell mitosis, enhancing the immune response. The nanobubbles' ultrasound responsiveness facilitates real-time imaging and controlled drug release, maximizing therapeutic efficacy while minimizing side effects. Key findings demonstrate that Ce6/PTX Nbs significantly reduced tumor growth in a 4T1 breast cancer model, enhanced immune activation via the cGAS-STING pathway, and increased the infiltration of CD8+ T cells in both primary and distant tumors. In combination with anti-PD-L1 checkpoint inhibitors, the treatment achieved a substantial suppression of tumor metastasis. This innovative approach offers a highly targeted, effective, and minimally toxic breast cancer treatment with potential for clinical translation due to its dual imaging and therapeutic capabilities.

Impact of tumor localization on antitumor immunity with conditionally activated CTLA-4 blockade

BACKGROUND

Immune checkpoint blockade (ICB) can induce antitumor efficacy but also induces immune-related adverse events. Systemically administered ICB can activate immune cells throughout the host. Conditionally active ICB with proteolytically cleaved masking domains can potentially reduce the adverse events seen with anti-cytotoxic T-lymphocyte associated protein 4 (CTLA-4) antibody.

METHODS

We examined how different formats of a conditionally activated dual variable domain IgG (DVD) that binds CTLA-4 and the tumor-associated antigen prostate stem cell antigen (PSCA) can lead to efficacy in syngeneic subcutaneous and metastatic murine tumor models. We also defined the capacity of these DVDs to modulate immune responses by multiparameter flow cytometry.

RESULTS

Conditionally active DVDs can uncouple antitumor efficacy from toxicity. A fully cleavable construct (symmetric DVD, sDVD), which can be released from the target tumor cells, showed superior antitumor efficacy compared with asymmetric DVD, which retains its tumor antigen binding. The sDVD elicited the highest tumor-antigen-specific T-cell responses detected in tumors and tumor-draining lymph nodes, as well as presenting the highest rate of intratumoral and splenic "non-exhausted" antigen-specific CD8 T cells. SDVD also induced the highest degrees of T-cell memory and self-renewal potential. These effects were dependent on PSCA expression by the tumors.

CONCLUSIONS

These findings support the notion that ICB modulation of antitumor immunity away from the tumor cells is critically important for optimal antitumor immunity. The bispecific sDVD antibody design may enable improved systemic antitumor responses than traditional ICB in both primary tumors and metastases.

IL-12-producing cytokine factories induce precursor exhausted T cells and elimination of primary and metastatic tumors

BACKGROUND

Curative responses to immunotherapy require the generation of robust systemic immunity with limited toxicity. Recruitment of T cell populations such as precursor exhausted T cells (Tpex) from lymphoid tissues to tumors is a hallmark of effective treatment. However, the ability to efficiently induce this recruitment is lacking in current immunotherapy approaches. Furthermore, systemic administration of immunotherapies frequently results in dose-limiting toxicities, yielding an inadequate therapeutic window for eliciting durable responses.

METHODS

In this investigation, we evaluated the safety and antitumor efficacy of locally administered interleukin 12 (IL-12) using a clinically translatable cytokine delivery platform (NCT05538624) to identify Tpex recruitment capabilities at tolerable cytokine doses.

RESULTS

We show IL-12 cytokine factories can effectively treat a broad spectrum of cancer types. Single-cell RNA sequencing data suggests that the antitumor efficacy seen in our studies was due to retinal pigmented epithelial cells-mIL12 treatment inducing differentiation of Tpex cells within the tumor microenvironment. When administered in combination with checkpoint therapy, IL-12 cytokine factory treatment generated systemic abscopal immunity, preventing subcutaneous tumor outgrowth in 8/9 mice with colorectal cancer and lung metastasis in mice with melanoma. Furthermore, this platform was well tolerated in a non-human primate without signs of toxicity.

CONCLUSIONS

Our new immunotherapy approach provides a robust strategy for inducing Tpex recruitment and systemic immunity against a range of solid peritoneal malignancies, many incurable with current immunotherapy strategies. Notably, these features were achieved using IL-12, and by leveraging our technology, we avoided the toxicities that have prevented the translation of IL-12 to the clinic. Our findings provide a strong rationale for the clinical development of IL-12 cytokine factories.

Cross-priming in cancer immunology and immunotherapy

Cytotoxic T cell immune responses against cancer crucially depend on the ability of a subtype of professional antigen-presenting cells termed conventional type 1 dendritic cells (cDC1s) to cross-present antigens. Cross-presentation comprises redirection of exogenous antigens taken from other cells to the major histocompatibility complex class I antigen-presenting machinery. In addition, once activated and having sensed viral moieties or T helper cell cooperation via CD40-CD40L interactions, cDC1s provide key co-stimulatory ligands and cytokines to mount and sustain CD8+ T cell immune responses. This regulated process of cognate T cell activation is termed cross-priming. In cancer mouse models, CD8+ T cell cross-priming by cDC1s is crucial for the efficacy of most, if not all, immunotherapy strategies. In patients with cancer, the presence and abundance of cDC1s in the tumour microenvironment is markedly associated with the level of T cell infiltration and responsiveness to immune checkpoint inhibitors. Therapeutic strategies to increase the numbers of cDC1s using FMS-like tyrosine kinase 3 ligand (FLT3L) and/or their activation status show evidence of efficacy in cancer mouse models and are currently being tested in initial clinical trials with promising results so far.

Molecular Mechanisms Governing CD8 T Cell Differentiation and Checkpoint Inhibitor Response in Cancer

CD8 T cells play a critical role in antitumor immunity. However, over time, they often become dysfunctional or exhausted and ultimately fail to control tumor growth. To effectively harness CD8 T cells for cancer immunotherapy, a detailed understanding of the mechanisms that govern their differentiation and function is crucial. This review summarizes our current knowledge of the molecular pathways that regulate CD8 T cell heterogeneity and function in chronic infection and cancer and outlines how T cells respond to therapeutic checkpoint blockade. We explore how T cell-intrinsic and -extrinsic factors influence CD8 T cell differentiation, fate choices, and functional states and ultimately dictate their response to therapy. Identifying cells that orchestrate long-term antitumor immunity and understanding the mechanisms that govern their development and persistence are critical steps toward improving cancer immunotherapy.

Two chemotherapeutic agents expand stem-like CD62L+CD8+ T cells in antitumor immune responses

Introduction

Recent findings reveal that the precursors of exhausted CD8+ T (CD8+ Tpex) cells possess stem-like signatures in tumor immunity, which originate from tumor draining lymph node (TdLN)-derived tumor-specific memory (CD8+ TTSM) cells. Both of these T subsets can be collectively referred to as stem-like CD8+ T cells, which demonstrate robust self-renewal ability and can proliferate and differentiate into transitory effector-like exhausted T cells (Texint). There are reports that chemotherapeutic drugs can promote the antitumor immune responses of patients by increasing the number of CD8+ T cells; however, whether chemotherapeutic drugs increase these two stem-like CD8+ T cells remain further exploration.

Methods

Tpex cell-associated subpopulations in human colorectal tumors were analyzed by using single-cell sequencing data. CT26 and B16 tumor models of wild type and Eomes conditional knockout mice were constructed, and the changes of TTSM, Tpex and Tex subsets in mice were dissected by flow cytometry after treatment with decitabine (DAC), doxorubicin (DOX) and 5-Fluorouracil (5-FU).

Results

In this study, we demonstrated that DAC and 5-FU expanded CD8+ TTSM cells in TdLNs. At the same time, we validated that DAC and 5-FU substantially promoted the expansion of CD62L+CD8+ Tpex cells and subsequently increased effector function of CX3CR1+ CD8+ Texint cells. In addition, the conditional knockout of transcription factor Eomes in CD8+ T cells partially eliminated DAC-amplified CD62L+ CD8+ Tpex cells, but had no effect on such CD8+ T subset expanded by 5-FU.

Conclusion

The present study demonstrated that both DAC and 5-FU promoted the differentiation of stem-like CD8+ TTSM cells in TdLNs and significantly enhanced the differentiation and expansion of stem-like CD62L+ CD8+ Tpex and CX3CR1+ Texint cells in tumor microenvironment. The knockout of Eomes partially influenced the role of DAC in promoting the differentiation and expansion of stem-like CD8+ T cells.

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.

cGAS and STING in Host Myeloid Cells Are Essential for Effective Cyclophosphamide Treatment of Advanced Breast Cancer

BACKGROUND/OBJECTIVES

Cyclophosphamide (CTX) treatment in vivo kills proliferating tumor cells by DNA crosslinking; however, the suppression of tumor growth by CTX in several murine models requires CD8+ T cells. Given that CTX induces DNA damage and type I interferon (IFN-I), we investigated the role of host cGAS and STING in the anti-tumor effect of CTX in vivo.

METHODS

A metastasized EO771 breast cancer model with chromosomal instability and bone marrow (BM) chimera approach were used in this study.

RESULTS

We found that CTX therapy induces long-term survival of the mice, with this outcome being dependent on CD8+ T cells and cGAS/STING of BM-derived cells. Furthermore, the STING of type 1 conventional dendritic cells (cDC1s) and LysM+ cells and the IFN-I response of non-cDC1 myeloid cells are essential for CTX efficacy. We also found that the cGAS and STING of BM-derived cells positively modulate intratumoral exhausted and stem-cell-like CD8+ T cell populations under CTX treatment, with the latter only being affected by cGAS.

CONCLUSIONS

Our study demonstrates that the CD8+-T-cell-dependent anti-tumor mechanisms of CTX critically involve the cGAS-STING-IFN-I axis, IFN-I response, and STING-independent cGAS function in host myeloid cells. These findings suggest the deployment of CTX in treating advanced solid tumor to bypass the often-failed IFN-I production by tumor cells due to the chronic activation of intrinsic cGAS-STING caused by chromosomal instability.

Oxaliplatin, ATR inhibitor and anti-PD-1 antibody combination therapy controls colon carcinoma growth, induces local and systemic changes in the immune compartment, and protects against tumor rechallenge in mice

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer type and one of the leading causes of cancer-related death worldwide. The treatment of advanced metastatic CRC relies on classical chemotherapy combinations (5-fluorouracil, oxaliplatin or irinotecan). However, their use is limited by the emergence of resistance mechanisms, including to oxaliplatin. In this context, we recently showed that the combination of oxaliplatin and ataxia telangiectasia and Rad3-related protein inhibition (VE-822) is synergistic and may have a potential therapeutic effect in metastatic CRC management.

METHODS

In this study, we investigated the role of the VE-822+oxaliplatin (Vox) combination on the immune response and its potential synergy with an anti-programmed-cell Death receptor-1 (PD-1) antibody. We used cell lines and organoids from metastatic CRC to investigate in vitro Vox efficacy and orthotopic syngeneic mouse models of metastatic CRC to assess the efficacy of Vox+anti-PD-1 antibody and identify the involved immune cells.

RESULTS

The Vox+anti-PD-1 antibody combination completely cured tumor-bearing mice and protected them from a rechallenge. Vox was associated with a reduction of tumor-infiltrated neutrophils, CD206+ macrophages and regulatory T cells. Vox also induced a deep depletion of blood neutrophils. The increased bone marrow granulopoiesis failed to compensate for the Vox-mediated mature neutrophil depletion. Neutrophil depletion using a mouse recombinant anti-Ly6G antibody partially mimicked the Vox effect on the tumor microenvironment, but to a lower extent compared with the Vox+anti-PD-1 antibody combination. Vox, but not neutrophil depletion, led to the emergence of an Ly6C+ PD-1+ CD8+ T-cell population in the blood and spleen of tumor-harboring mice. These cells were proliferating, and expressed IFN-γ, CD62L, CXCR3 and Eomes. Moreover, the proportion of tumor antigen-specific T cells and of CD122+ BCL6+ T cells, which shared phenotypic characteristics with stem-like CD8+ T cells, was increased in treated mice.

CONCLUSIONS

Our work strongly suggests that the Vox+anti-PD-1 antibody combination might significantly improve survival in patients with metastatic and treatment-refractory CRC by acting both on cancer cells and CD8+ T cells.

Protocol for investigating the impact of transcription regulator deficiency on tumor-specific CD8+ T cell responses via adoptive cell transfer

Transcription factors play a crucial role in the differentiation of tumor-specific CD8+ T cells and significantly influence their capacity to repress tumors. Here, we present a protocol for creating a transcription regulator inhibitor of DNA 3 (ID3) conditional knockout mouse in tumor-specific CD8+ T cells, induced by tamoxifen. We describe steps for examining the impact of ID3 deficiency on the differentiation of tumor-specific memory CD8+ T cells (Ttsm) and progenitors of exhausted CD8+ T cells (Tpex) in tumor-draining lymph nodes through a co-adoptive transfer assay. For complete details on the use and execution of this protocol, please refer to Ran et al.1.

Pipelines for lymphocyte homeostasis maintenance during cancer immunotherapy

In general, increasing lymphocyte entry into tumor microenvironment (TME) and limiting their efflux will have a positive effect on the efficacy of immunotherapy. Current studies suggest maintenance lymphocyte homeostasis during cancer immunotherapy through the two pipelines tumor-associated high endothelial venules and lymphatic vessels. Tumor-associated high endothelial venules (TA-HEVs) play a key role in cancer immunotherapy through facilitating lymphocyte trafficking to the tumor. While tumor-associated lymphatic vessels, in contrast, may promote the egress of lymphocytes and restrict their function. Therefore, the two traffic control points might be potential to maintain lymphocyte homeostasis in cancer during immunotherapy. Herein, we highlight the unexpected roles of lymphocyte circulation regulated by the two gateways for through reviewing the biological characters and functions of TA-HEVs and tumor-associated lymphatic vessels in the entry, positioning and exit of lymphocyte cells in TME during anti-tumor immunity.

Regulatory T cells constrain T cells of shared specificity to enforce tolerance during infection

During infections, CD4+ Foxp3+ regulatory T (Treg) cells must control autoreactive CD4+ conventional T (Tconv) cell responses against self-peptide antigens while permitting those against pathogen-derived "nonself" peptides. We defined the basis of this selectivity using mice in which Treg cells reactive to a single prostate-specific self-peptide were selectively depleted. We found that self-peptide-specific Treg cells were dispensable for the control of Tconv cells of matched specificity at homeostasis. However, they were required to control such Tconv cells and prevent autoimmunity toward the prostate after exposure to elevated self-peptide during infection. Notably, the Treg cell response to self-peptide did not affect protective Tconv cell responses to a pathogen-derived peptide. Thus, self-peptide-specific Treg cells promoted self-nonself discrimination during infection by selectively controlling Tconv cells of shared self-specificity.

Continuous replenishment of the dysfunctional CD8 T cell axis is associated with response to chemoimmunotherapy in advanced breast cancer

Chemotherapy combined with immune checkpoint blockade has shown clinical activity in breast cancer. Response, however, occurs in only a low proportion of patients. How the immune landscape of the tumor determines the immune and clinical responses to chemoimmunotherapy is not well understood. Here, using a combination of single-cell RNA sequencing (scRNA-seq) and single-cell T cell receptor sequencing (scTCR-seq), we profile 40 biopsies from 27 patients with metastatic triple-negative breast cancer (TNBC), receiving chemotherapy and anti-PD-L1 alone or in combination with anti-CD73, in a phase 2 randomized clinical trial. Our results show an enrichment of late-dysfunctional, clonally expanded CD8+ T cells in responder (R) patients. On treatment, R display an influx of newly emerging clonotypes, as well as expansion of the CD8+ precursors. Collectively, our data suggest that baseline clonal expansion could be a potential predictor of response and that both clonal reinvigoration of pre-existing tumor-reactive T cells and clonal replacement on-treatment are important for a protective response to chemoimmunotherapy.

IL-10-Directed Cancer Immunotherapy: Preclinical Advances, Clinical Insights, and Future Perspectives

Interleukin-10 (IL-10) is a dimeric cytokine encoded by the IL-10 gene on chromosome 1 [...].

CD4 T cell dysfunction is associated with bacterial recrudescence during chronic tuberculosis

While most people contain Mycobacterium tuberculosis infection, some individuals develop active disease, usually within two years of infection. Why immunity fails after initially controlling infection is unknown. C57BL/6 mice control Mycobacterium tuberculosis for up to a year but ultimately succumb to disease. We hypothesize that the development of CD4 T cell dysfunction permits bacterial recrudescence. We developed a reductionist model to assess antigen-specific T cells during chronic infection and found evidence of CD4 T cell senescence and exhaustion. In C57BL/6 mice, CD4 T cells upregulate coinhibitory receptors and lose effector cytokine production. Single cell RNAseq shows that only a small number of CD4 T cells in the lungs of chronically infected mice are polyfunctional. While the origin and causal relationship between T-cell dysfunction and recrudescence remains uncertain, we propose T cell dysfunction leads to a feed-forward loop that causes increased bacillary numbers, greater T cell dysfunction, and progressive disease.

Microglial reprogramming enhances antitumor immunity and immunotherapy response in melanoma brain metastases

Melanoma is one of the tumor types with the highest risk of brain metastasis. However, the biology of melanoma brain metastasis and the role of the brain immune microenvironment in treatment responses are not yet fully understood. Using preclinical models and single-cell transcriptomics, we have identified a mechanism that enhances antitumor immunity in melanoma brain metastasis. We show that activation of the Rela/Nuclear Factor κB (NF-κB) pathway in microglia promotes melanoma brain metastasis. Targeting this pathway elicits microglia reprogramming toward a proinflammatory phenotype, which enhances antitumor immunity and reduces brain metastatic burden. Furthermore, we found that proinflammatory microglial markers in melanoma brain metastasis are associated with improved responses to immune checkpoint inhibitors in patients and targeting Rela/NF-κB pathway in mice improves responses to these therapies in the brain, suggesting a strategy to enhance antitumor immunity and responses to immune checkpoint inhibitors in patients with melanoma brain metastasis.

Low-dose irradiation of the gut improves the efficacy of PD-L1 blockade in metastatic cancer patients

The mechanisms governing the abscopal effects of local radiotherapy in cancer patients remain an open conundrum. Here, we show that off-target intestinal low-dose irradiation (ILDR) increases the clinical benefits of immune checkpoint inhibitors or chemotherapy in eight retrospective cohorts of cancer patients and in tumor-bearing mice. The abscopal effects of ILDR depend on dosimetry (≥1 and ≤3 Gy) and on the metabolic and immune host-microbiota interaction at baseline allowing CD8+ T cell activation without exhaustion. Various strains of Christensenella minuta selectively boost the anti-cancer efficacy of ILDR and PD-L1 blockade, allowing emigration of intestinal PD-L1-expressing dendritic cells to tumor-draining lymph nodes. An interventional phase 2 study provides the proof-of-concept that ILDR can circumvent resistance to first- or second-line immunotherapy in cancer patients. Prospective clinical trials are warranted to define optimal dosimetry and indications for ILDR to maximize its therapeutic potential.

Profiling Multiple CD8+ T-cell Functional Dimensions Enhances Breast Cancer Immune Assessment

CD8+ T-cell abundance is insufficient to assess antitumor immunity and shows poor performance in predicting breast cancer prognosis and immunotherapy response, presumably owing to the complexity of CD8+ T-cell functionalities. Although single-cell RNA sequencing can dissect the multifaceted functions of CD8+ T cells for better immune assessment, its clinical application is limited. In this study, we developed bulk RNA sequencing-based FuncDimen models from integrative analysis of single-cell RNA sequencing and matched bulk RNA sequencing data to evaluate CD8+ T-cell functionalities across five dimensions: tumor reactivity, cytotoxicity, IFNγ secretion, proliferation, and apoptosis. The FuncDimen models quantifying different functional dimensions of CD8+ T cells were validated in our breast cancer cohort and external databases using immunofluorescence and imaging mass cytometry. We calculated the FuncAggre score by weighted aggregation of all five FuncDimen models to encapsulate the overall antitumor immunity. In our breast cancer cohort and external databases, the FuncAggre score demonstrated superior predictive performance for breast cancer prognosis (time-dependent AUC: 0.56-0.70) and immunotherapy response (AUC: 0.71-0.83) over other immune biomarkers, regardless of the breast cancer molecular subtype. Together, the FuncDimen models offer a refined assessment of antitumor immunity mediated by CD8+ T cells in the clinic, enhancing prognostic prediction and aiding personalized immunotherapy in breast cancer.

The XCL1-XCR1 axis supports intestinal tissue residency and antitumor immunity

Tissue-resident memory T cells (TRM) provide frontline protection against pathogens and emerging malignancies. Tumor-infiltrating lymphocytes (TIL) with TRM features are associated with improved clinical outcomes. However, the cellular interactions that program TRM differentiation and function are not well understood. Using murine genetic models and targeted spatial transcriptomics, we found that the CD8+ T cell-derived chemokine XCL1 is critical for TRM formation and conventional DC1 (cDC1) supported the positioning of intestinal CD8+ T cells during acute viral infection. In tumors, enforced Xcl1 expression by antigen-specific CD8+ T cells promoted intratumoral cDC1 accumulation and T cell persistence, leading to improved overall survival. Notably, analysis of human TIL and TRM revealed conserved expression of XCL1 and XCL2. Thus, we have shown that the XCL1-XCR1 axis plays a non-cell autonomous role in guiding intestinal CD8+ TRM spatial differentiation and tumor control.

Terminal differentiation and persistence of effector regulatory T cells essential for preventing intestinal inflammation

Regulatory T (Treg) cells are a specialized CD4+ T cell lineage with essential anti-inflammatory functions. Analysis of Treg cell adaptations to non-lymphoid tissues that enable their specialized immunosuppressive and tissue-supportive functions raises questions about the underlying mechanisms of these adaptations and whether they represent stable differentiation or reversible activation states. Here, we characterize distinct colonic effector Treg cell transcriptional programs. Attenuated T cell receptor (TCR) signaling and acquisition of substantial TCR-independent functionality seems to facilitate the terminal differentiation of a population of colonic effector Treg cells that are distinguished by stable expression of the immunomodulatory cytokine IL-10. Functional studies show that this subset of effector Treg cells, but not their expression of IL-10, is indispensable for colonic health. These findings identify core features of the terminal differentiation of effector Treg cells in non-lymphoid tissues and their function.

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.

A Copper-Manganese Based Nanocomposite Induces Cuproptosis and Potentiates Anti-Tumor Immune Responses

Cancer is one of the most important challenges worldwide with an increasing incidence. However, most of patients with malignant cancer receiving traditional therapies have tumor recurrence and short-term 5-year survival. Herein, a novel Cu2O-MnO@PEG (CMP) nanomaterial is developed to treat tumors. CMP directly mediates cuproptosis in tumor cells. Meanwhile, CMP potentiates anti-tumor immune responses in the tumor microenvironment (TME) to induce tumor regression. CMP improves the tumor antigen processing and presentation of dendritic cells and tumor-associated macrophages, and further promotes CD8+ T cell responses, especially for cytotoxic CD8+ T cells and transitory exhausted CD8+ T cells. Additionally, CMP downregulates the proportion of Treg cells and CTLA-4 expression on Treg cells. Notably, CMP induces systemic immune responses against distant tumors and long-term immune memory. Furthermore, CMP synergized with PD-L1 mAb promotes tumor inhibition and sustains the anti-tumor efficacy post PD-L1 mAb treatment. Collectively, this strategy has the clinically therapeutic potential for tumors by facilitating cuproptosis in tumor cells and anti-tumor immune responses.

Exploring the immuno-nano nexus: A paradigm shift in tumor vaccines

Tumor vaccines have become a crucial strategy in cancer immunotherapy. Challenges of traditional tumor vaccines include inadequate immune activation and low efficacy of antigen delivery. Nanoparticles, with their tunable properties and versatile functionalities, have redefined the landscape of tumor vaccine design. In this review, we outline the multifaceted roles of nanoparticles in tumor vaccines, ranging from their capacity as delivery vehicles to their function as immunomodulatory adjuvants capable of stimulating anti-tumor immunity. We discuss how this innovative approach significantly boosts antigen presentation by leveraging tailored nanoparticles that facilitate efficient uptake by antigen-presenting cells. These nanoparticles have been meticulously designed to overcome biological barriers, ensuring optimal delivery to lymph nodes and effective interaction with the immune system. Overall, this review highlights the transformative power of nanotechnology in redefining the principles of tumor vaccines. The intent is to inform more efficacious and precise cancer immunotherapies. The integration of these advanced nanotechnological strategies should unlock new frontiers in tumor vaccine development, enhancing their potential to elicit robust and durable anti-tumor immunity.

Primary and Acquired Resistance to Immunotherapy with Checkpoint Inhibitors in NSCLC: From Bedside to Bench and Back

Immunotherapy with checkpoint inhibitors has become the cornerstone of systemic treatment for non-oncogene addicted non-small-cell lung cancer. Despite its pivotal role, a significant proportion of patients-approximately 70-85%-either exhibit primary resistance to PD-1 blockade or develop acquired resistance following an initial benefit, even in combination with chemotherapy and/or anti-CTLA-4 agents. The phenomenon of primary and acquired resistance to immunotherapy represents a critical clinical challenge, largely based on our incomplete understanding of the mechanisms of action of immunotherapy, and the resulting lack of accurate predictive biomarkers. Here, we review the definitions and explore the proposed mechanisms of primary and acquired resistance, including those related to the tumor microenvironment, systemic factors, and intrinsic tumor characteristics. We also discuss translational data on adaptive changes within tumor cells and the immune infiltrate following exposure to checkpoint inhibitors. Lastly, we offer a comprehensive overview of current and emerging therapeutic strategies designed to prevent primary resistance and counteract acquired resistance.

Neoadjuvant cabozantinib for locally advanced nonmetastatic clear cell renal cell carcinoma: a phase 2 trial

Cabozantinib is an oral multikinase inhibitor approved for treatment in metastatic renal cell carcinoma (RCC). We conducted a phase 2, nonrandomized, single-arm clinical trial (NCT04022343) of cabozantinib treatment for 12 weeks in 17 patients with locally advanced, biopsy-proven, nonmetastatic clear cell RCC before surgical resection. The primary end point was the objective response rate (complete and partial responses) at week 12 and secondary end points included safety, tolerability, clinical and surgical outcomes, and quality of life. Six patients (35%) experienced a partial response and 11 patients (65%) had stable disease. The most common adverse events were diarrhea (n = 12, 70.6%), anorexia, fatigue and hypertension (n = 10, 58.8%), nausea and palmar-plantar erythrodysesthesia syndrome (n = 9, 52.9%). No treatment grade 4 or 5 adverse events related to cabozantinib or surgery occurred. The 1-year disease-free survival and overall survival were 82.4% (95% CI 54.7-93.9%) and 94.1% (95% CI 65-99.1%), respectively. Cabozantinib treatment activated CD8+ T cells in the blood, depleted myeloid populations and induced immune niches for TCF1+ stem-like CD8+ T cells. Cabozantinib was clinically active and safe in the neoadjuvant setting in patients with locally advanced nonmetastatic clear cell RCC.

Vax-Innate: improving therapeutic cancer vaccines by modulating T cells and the tumour microenvironment

T cells have a critical role in mediating antitumour immunity. The success of immune checkpoint inhibitors (ICIs) for cancer treatment highlights how enhancing endogenous T cell responses can mediate tumour regression. However, mortality remains high for many cancers, especially in the metastatic setting. Based on advances in the genetic characterization of tumours and identification of tumour-specific antigens, individualized therapeutic cancer vaccines targeting mutated tumour antigens (neoantigens) are being developed to generate tumour-specific T cells for improved therapeutic responses. Early clinical trials using individualized neoantigen vaccines for patients with advanced disease had limited clinical efficacy despite demonstrated induction of T cell responses. Therefore, enhancing T cell activity by improving the magnitude, quality and breadth of T cell responses following vaccination is one current goal for improving outcome against metastatic tumours. Another major consideration is how T cells can be further optimized to function within the tumour microenvironment (TME). In this Perspective, we focus on neoantigen vaccines and propose a new approach, termed Vax-Innate, in which vaccination through intravenous delivery or in combination with tumour-targeting immune modulators may improve antitumour efficacy by simultaneously increasing the magnitude, quality and breadth of T cells while transforming the TME into a largely immunostimulatory environment for T cells.

A microRNA-regulated transcriptional state defines intratumoral CD8+ T cells that respond to immunotherapy

The rising incidence of advanced-stage colorectal cancer (CRC) and poor survival outcomes necessitate new and effective therapies. Immune checkpoint inhibitors (ICIs), specifically anti-PD-1 therapy, show promise, yet clinical determinants of a positive response are suboptimal. Here, we identify microRNA-155 (miR-155) as necessary for CD8+ T cell-infiltrated tumors through an unbiased in vivo CRISPR-Cas9 screen identifying functional tumor antigen-specific CD8+ T cell-expressed microRNAs. T cell miR-155 is required for anti-PD-1 responses and for a vital intratumor CD8+ T cell differentiation cascade by repressing Ship-1, inhibiting Tcf-1 and stemness, and subsequently enhancing Cxcr6 expression, anti-tumor immunity, and effector functions. Based on an underlying miR-155-dependent CD8+ T cell transcriptional profile, we identify a gene signature that predicts ICI responses across 12 diverse cancers. Together, our findings support a model whereby miR-155 serves as a central regulator of CD8+ T cell-dependent cancer immunity and ICI responses that may be leveraged for future therapeutics.

UFL1 promotes survival and function of virtual memory CD8 T cells

In naïve mice, a fraction of CD8 T cells displaying high affinity for self-MHC peptide complexes develop into virtual memory T (TVM) cells. Due to self-reactivity, TVM cells are exposed to persistent antigenic stimulation, a condition known to induce T cell exhaustion. However, TVM cells do not exhibit characteristics similar to exhausted CD8 T (TEX) cells. Here, we tested the role of the UFL1, E3 ligase of the ufmylation pathway in TVM cells. We show that UFL1 prevents the acquisition of epigenetic, transcriptional, and phenotypic changes in TVM cells that are similar to TEX cells and thus promote their survival and function. UFL1-deficient TVM cells failed to protect mice against Listeria infection. Epigenetic analysis showed higher BATF activity in UFL1-deficient TVM cells. Deletion of BATF and not PD1 decreased inhibitory molecules expression and restored the survival and function of UFL1-deficient TVM cells. Our findings demonstrate a key role of UFL1 in inhibiting the exhaustion of TVM cells and promoting their survival and function.