T-cell exhaustion in the tumor microenvironment

Hybrid IgE-IgG1 antibodies (IgEG): a new antibody class that combines IgE and IgG functionality

IgG-based anti-cancer therapies have achieved promising clinical outcomes, but, especially for patients with solid tumors, response rates vary. IgE antibodies promote distinct immune responses compared to IgG and have shown anti-tumoral pre-clinical activity and preliminary efficacy and safety profile in clinical testing. To improve potency further, we engineered a hybrid IgE-IgG1 antibody (IgEG), to combine the functions of both isotypes. Two IgEGs were generated with variable regions taken from trastuzumab (Tras IgEG) and from a novel anti-HER2 IgE (26 IgEG). Both IgEGs expressed well in mammalian cells and demonstrated IgE-like stability. IgEGs demonstrated both IgE and IgG1 functionality in vitro. A lack of type I hypersensitivity associated with IgEG incubation with human blood is suggestive of acceptable safety. In vivo, IgEGs exhibited distinct pharmacokinetic profiles and produced anti-tumoral efficacy comparable to IgE. These findings highlight the potential of IgEG as a new therapeutic modality in oncology.

Hierarchical protein nano-crystalline hydrogel with extracellular vesicles for ectopic lymphoid structure formation

Among cancer therapies, immune checkpoint blockade (ICB) has emerged as a prominent approach, substantially enhancing anti-tumor immune responses. However, the efficacy of ICB is often limited in the absence of a pre-existing immune response within the tumor microenvironment. Here, we introduce a novel hierarchical protein hydrogel platform designed to facilitate the formation of artificial tertiary lymphoid structures (aTLS), thereby improving ICB efficacy. Through the integration of self-assembling ferritin protein nanocages, rec1-resilin protein, and CP05 peptide, our hierarchical hydrogels provide a structurally supportive and functionally adaptive scaffold capable of on-demand self-repair in response to mild thermal treatments. The effective encapsulation of extracellular vesicles (EVs) via the CP05 peptide ensures the formation of aTLS with germinal center-like structures within the hierarchical hydrogel. We demonstrate that, combined with ICB therapy, EV-loaded hierarchical hydrogels also induce the TLS within the tumor, markedly promoting immune responses against ICB-resistant tumor. This bioactive hydrogel platform offers a versatile tool for enhancing a broad range of immunotherapies, with potential applications extending beyond TLS to other frameworks that support complex tissue architectures.

Bacterial vaginosis associates with dysfunctional T cells and altered soluble immune factors in the cervicovaginal tract

BACKGROUNDBacterial vaginosis (BV) is a dysbiosis of the vaginal microbiome that is prevalent among reproductive-age females worldwide. Adverse health outcomes associated with BV include an increased risk of sexually acquired HIV, yet the immunological mechanisms underlying this association are not well understood.METHODSTo investigate BV-driven changes to cervicovaginal tract (CVT) and circulating T cell phenotypes, Kinga Study participants with or without BV provided vaginal tract (VT) and ectocervical (CX) tissue biopsies and PBMC samples.RESULTSHigh-parameter flow cytometry revealed an increased frequency of cervical CD4+ conventional T (Tconv) cells expressing CCR5 in BR+ versus BR- women. However, we found no difference in the number of CD3+CD4+CCR5+ cells in the CX or VT of BV+ versus BV- individuals, suggesting that BV-driven increased HIV susceptibility may not be solely attributed to increased CVT HIV target cell abundance. Flow cytometry also revealed that individuals with BV had an increased frequency of dysfunctional CX and VT CD39+ Tconv and CX tissue-resident CD69+CD103+ Tconv cells, reported to be implicated in HIV acquisition risk and replication. Many soluble immune factor differences in the CVT further support that BV elicits diverse and complex CVT immune alterations.CONCLUSIONOur comprehensive analysis expands on potential immunological mechanisms that may underlie the adverse health outcomes associated with BV, including increased HIV susceptibility.TRIAL REGISTRATIONClinicalTrials.gov NCT03701802.FUNDINGThis work was supported by National Institutes of Health grants R01AI131914, R01AI141435, and R01AI129715.

Reactivation of CTLA4-expressing T cells accelerates resolution of lung fibrosis in a humanized mouse model

Tissue regenerative responses involve complex interactions between resident structural and immune cells. Recent reports indicate that accumulation of senescent cells during injury repair contributes to pathological tissue fibrosis. Using tissue-based spatial transcriptomics and proteomics, we identified upregulation of the immune checkpoint protein, cytotoxic T lymphocyte-associated protein 4 (CTLA4), on CD8+ T cells adjacent to regions of active fibrogenesis in human idiopathic pulmonary fibrosis and in a repetitive bleomycin lung injury murine model of persistent fibrosis. In humanized CTLA4-knockin mice, treatment with ipilimumab, an FDA-approved drug that targets CTLA4, resulted in accelerated lung epithelial regeneration and diminished fibrosis from repetitive bleomycin injury. Ipilimumab treatment resulted in the expansion of Cd3e+ T cells, diminished accumulation of senescent cells, and robust expansion of type 2 alveolar epithelial cells, facultative progenitor cells of the alveolar epithelium. Ex vivo activation of isolated CTLA4-expressing CD8+ cells from mice with established fibrosis resulted in enhanced cytolysis of senescent cells, suggesting that impaired immune-mediated clearance of these cells contributes to persistence of lung fibrosis in this murine model. Our studies support the concept that endogenous immune surveillance of senescent cells may be essential in promoting tissue regenerative responses that facilitate the resolution of fibrosis.

Advances in T Cell-Based Cancer Immunotherapy: From Fundamental Mechanisms to Clinical Prospects

T cells and their T cell receptors (TCRs) play crucial roles in the adaptive immune system's response against pathogens and tumors. However, immunosenescence, characterized by declining T cell function and quantity with age, significantly impairs antitumor immunity. Recent years have witnessed remarkable progress in T cell-based cancer treatments, driven by a deeper understanding of T cell biology and innovative screening technologies. This review comprehensively examines T cell maturation mechanisms, T cell-mediated antitumor responses, and the implications of thymic involution on T cell diversity and cancer prognosis. We discuss recent advances in adoptive T cell therapies, including tumor-infiltrating lymphocyte (TIL) therapy, engineered T cell receptor (TCR-T) therapy, and chimeric antigen receptor T cell (CAR-T) therapy. Notably, we highlight emerging DNA-encoded library technologies in mammalian cells for high-throughput screening of TCR-antigen interactions, which are revolutionizing the discovery of novel tumor antigens and optimization of TCR affinity. The review also explores strategies to overcome challenges in the solid tumor microenvironment and emerging approaches to enhance the efficacy of T cell therapy. As our understanding of T cell biology deepens and screening technologies advances, T cell-based immunotherapies show increasing promise for delivering durable clinical benefits to a broader patient population.

Impact of Tertiary Lymphoid Structure on Prognosis and Tumor Microenvironment in Undifferentiated Pleomorphic Sarcoma

Undifferentiated pleomorphic sarcoma (UPS) has a favorable objective response rate to anti-PD-1 drugs compared with other sarcomas. Tertiary lymphoid structure (TLS) is a favorable prognostic factor and a biomarker for immune checkpoint inhibitors (ICIs). Nevertheless, there are limited data on the tumor microenvironment (TME) to support a good response to ICIs in sarcoma. Therefore, this study was conducted to investigate the impact of TLS on prognosis and TME. A total of 52 of UPS with wide resection were divided into intratumoral TLS, extratumoral TLS, and without TLS groups. Survival analysis and immunohistochemistry were performed to evaluate immune cells and immune checkpoint molecules, and multiplexed immunofluorescence was conducted to evaluate T-cell exhaustion among the three groups. TLS was detected in 34 cases (65%), including 23 intratumoral TLS (44%) and 11 extratumoral TLS (21%) cases. Patients with TLS had significantly longer overall survival than those without TLS (log rank p = 0.020). The intratumoral TLS group had a significantly higher number of immune cells and higher expression of PD-L1 and IDO-1 than the without TLS group. Progenitor-exhausted T cells were also observed in patients with UPS. In conclusion, these findings could help predict prognosis in patients with UPS. TLS was demonstrated to be a favorable prognostic factor in patients with UPS. Intratumoral TLS may be a biomarker for the response to ICIs, especially anti-PD-1 drugs.

Anti-PD1 prolongs the response of PI3K and farnesyl transferase inhibition in HRAS- and PIK3CA-mutant head and neck cancers

BACKGROUND

Tipifarnib, a farnesyl transferase inhibitor, has shown promising response in the treatment of HRAS-mutant HNSCC in the clinic, and in combination with a PI3K inhibitor in PIK3CA-mutant mouse models; however, the involvement of antitumor immunity in the efficacy of tipifarnib has not yet been investigated. This study aimed to evaluate the involvement of antitumor immunity in the efficacy of tipifarnib in HRAS- or PIK3CA-mutant HPV-positive and HPV-negative head and neck cancer murine models.

METHODS

To investigate the role of antitumor immunity, we compared the efficacy of tipifarnib in immune-intact C57BL/6 mice and immunodeficient NSG mice. Histopathological analyses were conducted to evaluate PD-L1 expression and the activation of key signaling pathways. Additionally, the synergistic potential of tipifarnib with the PI3Kα inhibitor alpelisib (BYL719) was assessed in vitro and in vivo. Immunohistochemical analysis was performed to examine the infiltration of CD8+T cells, and anti-PD1 treatment was tested to evaluate its potential to prolong progression-free survival.

RESULTS

In the HPV-positive HRAS-mutant HNSCC model, the antitumor efficacy of tipifarnib was primarily dependent on CD8+T cell activity, whereas in HPV-negative cancers, the contribution of antitumor immunity was less pronounced. Tipifarnib treatment upregulated PD-L1 expression, potentially inhibiting T cell antitumor activity and inducing hyperactivation of the AKT pathway, which mitigated MAPK inhibition and promoted cell proliferation. Blocking the PI3K pathway with alpelisib demonstrated synergistic antitumor effects in all models. The combination of tipifarnib and alpelisib exhibited greater efficacy in immune-intact mice than in immunodeficient mice, and was accompanied by increased CD8+T cell infiltration. Adding anti-PD1 treatment to the tipifarnib/alpelisib combination further prolonged progression-free survival in tumor-bearing mice.

CONCLUSION

These findings underscore the critical role of antitumor immunity, particularly CD8+T cell activity, in the efficacy of tipifarnib alone and in combination with alpelisib. The triple combination of tipifarnib, alpelisib, and anti-PD1 treatment showed superior antitumor activity and extended survival in preclinical models, suggesting its potential as a therapeutic strategy for HNSCC patients with HRAS- and PIK3CA-mutation.

Harnessing Immune Rejuvenation: Advances in Overcoming T Cell Senescence and Exhaustion in Cancer Immunotherapy

Immunotherapy has transformed the landscape of cancer treatment, with T cell-based strategies at the forefront of this revolution. However, the durability of these responses is frequently undermined by two intertwined phenomena: T cell exhaustion and senescence. While exhaustion is driven by chronic antigen exposure in the immunosuppressive tumor microenvironment, leading to a reversible state of diminished functionality, senescence reflects a more permanent, age- or stress-induced arrest in cellular proliferation and effector capacity. Together, these processes represent formidable barriers to sustained anti-tumor immunity. In this review, we dissect the molecular underpinnings of T cell exhaustion and senescence, revealing how these dysfunctions synergistically contribute to immune evasion and resistance across a range of solid tumors. We explore cutting-edge therapeutic approaches aimed at rewiring the exhausted and senescent T cell phenotypes. These include advances in immune checkpoint blockade, the engineering of "armored" CAR-T cells, senolytic therapies that selectively eliminate senescent cells, and novel interventions that reinvigorate the immune system's capacity for tumor eradication. By spotlighting emerging strategies that target both exhaustion and senescence, we provide a forward-looking perspective on the potential to harness immune rejuvenation. This comprehensive review outlines the next frontier in cancer immunotherapy: unlocking durable responses by overcoming the immune system's intrinsic aging and exhaustion, ultimately paving the way for transformative therapeutic breakthroughs.

Progressive accumulation of circulating CD27-CD28- effector/memory CD8+ T cells in patients with lung cancer blunts responses to immune checkpoint inhibitor therapy

Suppression of tumor-reactive CD8+ T cells is common within the tumor microenvironment. However, little is known about how tumors systemically affect the overall CD8+ T cell compartment. Here we demonstrate that peripheral blood CD8+ T cells from patients with lung cancer showed altered compositions particularly within CD45RA-CCR7- effector memory subpopulation. Specifically, patients with lung cancer exhibited increased frequency of more differentiated effector memory cells, which are less susceptible to T cell-receptor-induced proliferation. Further analysis using single-cell RNA sequencing revealed that these alterations were correlated with reduced quiescence and increased spontaneous activation at a systemic level, indicative of homeostatic dysregulation of the entire CD8+ T cell population. This phenomenon was found to be correlated with a poor clinical response to immune checkpoint inhibitor therapy across four independent cohorts, consisting of a total of 224 patients with lung cancer. These findings suggest that lung cancers continue to counteract potentially tumor-reactive CD8+ T cells by inducing homeostatic dysregulation of the entire CD8+ T cell compartment systematically.

Dual prophylactic and therapeutic potential of iPSC-based vaccines and neoantigen discovery in colorectal cancer

Rationale: Induced pluripotent stem cells (iPSCs) share transcriptomic similarities with cancer cells and express tumor-specific and tumor-associated antigens, highlighting their potential as cancer vaccines. Our previous study demonstrated that an iPSC-based vaccine effectively prevented tumor growth in various mouse models, including melanoma, breast, lung, and pancreatic cancers. However, the underlying mechanisms and the therapeutic efficacy of the iPSC-based vaccine remain unclear. Colorectal cancer (CRC), the third most common cancer with a rising incidence worldwide, presents an urgent need for novel strategies to prevent and treat CRC. Methods: Allograft mouse models were established to evaluate the antitumor effects of the iPSC-based vaccine. CpG oligonucleotide (ODN) 1826 served as a vaccine adjuvant. Bulk RNA-Sequencing (RNA-Seq) and the Microenvironment Cell Population counter (MCP-Counter) algorithm were performed to analyze transcriptomic changes. Liquid chromatography-mass spectrometry (LC-MS) combined with in silico strategies was employed to identify potential antigen proteins. Chinese Hamster Ovary (CHO-K1) models were utilized to express candidate neoantigen proteins. Mouse bone marrow-derived dendritic cells (BMDCs) were used to investigate T cell priming in response to iPSC-associated proteins. Immune cell profiles were characterized by flow cytometry. Results: The combination of CpG and iPSC vaccination demonstrated both prophylactic and therapeutic efficacy in reducing tumor growth in CRC mouse models. Vaccination significantly increased CD8+ T cell infiltration within tumor regions, while T cell depletion abrogated the antitumor effects, underscoring the critical role of T cells in mediating these responses. Proteomic analysis identified two iPSC-associated proteins, heterogeneous nuclear ribonucleoprotein U (HNRNPU) and nucleolin (NCL), as key drivers of the observed immune responses. Vaccination with HNRNPU or NCL, in combination with CpG, enhanced dendritic cell activation, induced antigen-specific CD8+ T cell cytotoxicity, and promoted the formation of central memory CD8+ T cells, collectively leading to significant CRC tumor shrinkage. Conclusions: Our findings reveal potential mechanisms underlying the efficacy of iPSC-based vaccines in cancer immunotherapy. Additionally, HNRNPU and NCL were identified as key antigen proteins in iPSC, demonstrating promise for the development of peptide-based vaccines for both the prevention and treatment of CRC.

Multifaceted functions of tissue-resident memory T cells in tumorigenesis and cancer immunotherapy

Tissue-resident memory T (TRM) cells are well reported as a strong protective first line of defense against foreign antigens in non-lymphoid tissues. Moreover, TRM cells have demonstrated critical protective roles in antitumor immunity, contributing to enhanced survival and tumor growth inhibition across various cancer types. However, surprisingly, recent studies suggest that TRM cells can exhibit paradoxical effects, potentially promoting tumor progression under certain conditions and leading to adverse outcomes during antitumor immune responses. Understanding the complexities of TRM cell functions will enable us to harness their potential in advancing cancer immunotherapy more effectively. Therefore, this review comprehensively investigates the dual roles of TRM cells in different tumor contexts, highlighting their protective functions in combating cancers and their unfavorable potential to exacerbate tumor development. Additionally, we explore the implications of TRM cell behaviors for future cancer treatment strategies, emphasizing the need for further research to optimize the therapeutic exploitation of TRM cells while mitigating their deleterious effects.

Population analysis and immunologic landscape of melanoma in people living with HIV

People living with HIV (PLWH) diagnosed with melanoma have consistently exhibited worse clinical outcomes than HIV-negative individuals (PLw/oH) with the same cancer, even in the era of antiretroviral therapy (ART). To investigate the underlying factors contributing to these disparities, we analyzed electronic health records from 922 PLWH and 334,972 PLw/oH with melanoma. PLWH were diagnosed with melanoma at a younger age and had a higher representation of Hispanic and Black individuals. Notably, PLWH had a markedly increased risk of brain metastases. Additionally, despite similar treatment durations, PLWH experienced significant delays in initiating immune checkpoint therapy (ICI) and exhibited worse survival outcomes at both five- and ten-years post-treatment with ICI. To explore potential biological determinants of these disparities, we conducted spatial immune transcriptomics on melanoma tumors (n=11). This analysis revealed a more immunosuppressive tumor landscape in PLWH, characterized by upregulated immune checkpoints (e.g., PD1, LAG3, CTLA4) and diminished antigen presentation (e.g., HLA-DRB, B2M ), with distinct spatial distributions in the tumors versus the tumor microenvironments. Downstream validation via multiplex immunofluorescence (n=15 PLWH, n=14 PLw/oH) confirmed an exhausted CD8 + T cell compartment, marked by enrichment of PD1 int LAG3 - and PD1 int LAG3 + subpopulations, along with a significant accumulation of immunosuppressive myeloid-derived suppressor cells (CD11b + HLA-DR - CD33 + ) in PLWH. These distinct immune profiles suggest chronic HIV infection fosters a permissive tumor microenvironment that might undermine effective immune responses and contribute to poor clinical outcomes for PLWH with melanoma. Targeting the actionable immune pathways identified in this study could inform tailored therapeutic strategies to mitigate these disparities.

From ex vivo to in vitro models: towards a novel approach to investigate the efficacy of immunotherapies on exhausted Vγ9Vδ2 T cells?

Human γδ T cells demonstrate remarkable and diverse antitumor properties driven by TCR-dependent activation. Their non-alloreactive nature and pivotal role in cancer immunity position them as attractive targets for immunotherapies. However, upon infiltrating tumors, due to mechanisms induced by the tumor microenvironment's immune evasion strategies, these cells frequently become exhausted, greatly weakening the efficacy and antitumor potential of novel immunotherapeutic treatments. While being extensively characterized in CD8+ T cells, research on γδ T cell exhaustion remains scarce. There is a growing need for comprehensive models to investigate the reinvigoration properties of exhausted γδ T cells. This review synthesizes current strategies and models for evaluating novel immunotherapies aimed at rejuvenating exhausted γδ T cells. It explores a progression of approaches, from ex vivo studies and in vivo murine models to emerging in vitro systems. The advantages and limitations of these models are discussed to provide a comprehensive understanding of their potential in advancing therapeutic research. Furthermore, recent findings suggesting in vitro exhaustion phenotypes closely mirror those observed ex vivo highlight opportunities for preclinical innovation. By refining these models, researchers can better optimize the immunotherapies targeting this unique T cell subset.

Single-Cell Profiling Reveals Global Immune Responses During the Progression of Murine Epidermal Neoplasms

BACKGROUND/OBJECTIVES

Immune cells determine the role of the tumor microenvironment during tumor progression, either suppressing tumor formation or promoting tumorigenesis. This study aimed to fully characterize immune cell responses during skin tumor progression.

METHODS

Using single-cell RNA sequencing, we analyzed the profile of immune cells in the tumor microenvironment of control mouse skins and skin tumors at the single-cell level.

RESULTS

We identified 15 CD45+ immune cell clusters, which broadly represent the most functionally characterized immune cell types including macrophages, Langerhans cells (LC), conventional type 1 dendritic cells (cDC1), conventional type 2 dendritic cells (cDC2), migratory/mature dendritic cells (mDC), dendritic epidermal T cells (DETC), dermal γδ T cells (γδT), T cells, regulatory T cells (Tregs), natural killer cells (NK), type 2 innate lymphoid cells (ILC2), neutrophils (Neu), mast cells (Mast), and two proliferating populations (Prolif.1 and Prolif.2). Skin tumor progression reprogramed immune cells and led to a marked increase in the relative percentages of macrophages, cDC2, mDC, Tregs, and Neu. Macrophages, the largest cell cluster of immune cells in skin tumors. In addition, macrophages emerged as the predominant communication 'hub' in skin tumors, highlighting the importance of macrophages during skin tumor progression. In contrast, other immune cell clusters decreased during skin tumor progression, including DETC, γδT, ILC2, and LC. In addition, skin tumor progression dramatically upregulated Jak2/Stat3 expression and the interferon response across various immune cell clusters. Further, skin tumor progression activated T cells and NK cells indicated by elevated expression of IFN-γ and Granzyme B in skin tumors. Meanwhile, a pronounced infiltration of M2-macrophages and Tregs in skin tumors created an immunosuppressive microenvironment, consistent with the elevated expression of the Stat3 pathway in skin tumors.

CONCLUSIONS

Our study elucidates the immune cell landscape of epidermal neoplasms, offering a comprehensive understanding of the immune response during skin tumor progression and providing new insights into cancer immune evasion mechanisms.

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.

Memory-promoting function of miR-379-5p attenuates CD8+ T cell exhaustion by targeting immune checkpoints

BACKGROUND

MicroRNAs (miRNAs) are epigenetic regulators of T cell maturation and exhaustion. However, the mechanisms by which miRNAs influence T cell function in tumor environments remain unclear. This study focuses on miR-379-5p, which counteracts T cell exhaustion and enhances antitumor responses.

METHODS

Native CD8+ T cells were isolated from the blood of healthy donors and subjected to chronic stimulation to induce exhaustion. RNA sequencing and miRNA sequencing were performed to identify differentially expressed miRNAs. These miRNAs underwent bioinformatics analyses, including DESeq enrichment, immune cell infiltration assessment, and patient prognostic outcomes in The Cancer Genome Atlas data sets to assess their potential involvement in T cell exhaustion and antitumor immunity. The biological functions of miRNA on T cell differentiation, cytotoxic killing, and immune checkpoint regulation were investigated using in vitro assays, OT-I B16F10-OVA models, and patient-derived tumor organoids.

RESULTS

MiR-379-5p is downregulated in exhausted T cells and negatively associated with exhausted tumor-infiltrating lymphocytes in advanced tumors. It correlates positively with better survival outcomes in breast cancer, cervical cancer and melanoma. In CD8+ T cells, miR-379-5p reduces the expression of immune checkpoint proteins T cell immunoglobulin and mucin-domain containing-3 (TIM3) and T cell immunoreceptor with Ig and ITIM domains (TIGIT) by targeting their 3' untranslated region. Overexpression of miR-379-5p in CD8+ T cell promotes differentiation into memory-like T effector cells and enhances cytotoxic killing of cancer cells. The transcription factor nuclear receptor subfamily 4 group A member 1 (NR4A1) with increased expression in exhausted T cells and negatively regulates miR-379, restoring immune checkpoint expression and suppressing cancer-killing ability. In contrast, OT-I T cells expressing ectopic miR-379-5p show increased cytotoxicity against B16F10-OVA tumors in mice. Autologous T cells isolated from patients with breast cancer transduced with miR-379-5p significantly improve killing of tumor organoids derived from the same patients.

CONCLUSIONS

MiR-379-5p acts as an epigenetic tumor suppressor by enhancing CD8+ T cell effector functions and suppressing T cell exhaustion. MiR-379-5p could represent a novel marker and strategy for cancer immunotherapy, offering promising avenues for enhancing antitumor immune responses.

Intratumoral mycobiome heterogeneity influences the tumor microenvironment and immunotherapy outcomes in renal cell carcinoma

The intratumoral mycobiome plays a crucial role in the tumor microenvironment, but its impact on renal cell carcinoma (RCC) remains unclear. We collected and quantitatively profiled the intratumoral mycobiome data from 1044 patients with RCC across four international cohorts, of which 466 patients received immunotherapy. Patients were stratified into mycobiota ecology-depauperate and mycobiota ecology-flourishing (MEF) groups based on fungal abundance. The MEF group had worse prognosis, higher fungal diversity, down-regulated lipid catabolism, and exhausted CD8+ T cells. We developed the intratumoral mycobiota signature and intratumoral mycobiota-related genes expression signature, which robustly predicted prognosis and immunotherapy outcomes in RCC and other cancers. Aspergillus tanneri was identified as a potential key fungal species influencing RCC prognosis. Our findings suggest that the intratumoral mycobiome suppresses lipid catabolism and induces T cell exhaustion in RCC.

Where lung cancer and tuberculosis intersect: recent advances

Lung cancer (LC) and tuberculosis (TB) represent two major global public health issues. Prior evidence has suggested a link between TB infection and an increased risk of LC. As advancements in LC treatment have led to extended survival rates for LC patients, the co-occurrence of TB and LC has grown more prevalent and poses novel clinical challenges. The intricate molecular mechanisms connecting TB and LC are closely intertwined and many issues remain to be addressed. This review focuses on resemblance between the immunosuppression in tumor and granuloma microenvironments, exploring immunometabolism, cell plasticity, inflammatory signaling pathways, microbiomics, and up-to-date information derived from spatial multi-omics between TB and LC. Furthermore, we outline immunization-related molecular mechanisms underlying these two diseases and propose future research directions. By discussing recent advances and potential targets, this review aims to establish a foundation for developing future therapeutic strategies targeting LC with concurrent TB infection.

The Impact of T-cell Exhaustion Dynamics on Tumour-Immune Interactions and Tumour Growth

Tumours evade immune surveillance through a number of different immunosuppressive mechanisms. One such mechanism causes cytotoxic T-cells, a major driving force of the immune system, to differentiate to a state of 'exhaustion', rendering them less effective at killing tumour cells. We present a structured mathematical model that focuses on T-cell exhaustion and its effect on tumour growth. We compartmentalise cytotoxic T-cells into discrete subgroups based on their exhaustion level, which affects their ability to kill tumour cells. We show that the model reduces to a simpler system of ordinary differential equations (ODEs) that describes the time evolution of the total number of T-cells, their mean exhaustion level and the total number of tumour cells. Numerical simulations of the model equations reveal how the exhaustion distribution of T-cells changes over time and how it influences the tumour's growth dynamics. Complementary bifurcation analysis shows how altering key parameters significantly reduces the tumour burden, highlighting exhaustion as a promising target for immunotherapy. Finally, we derive a continuum approximation of the discrete ODE model, which admits analytical solutions that provide complementary insight into T-cell exhaustion dynamics and their effect on tumour growth.

Rejuvenation of Tumor-Specific T Cells via Ultrahigh DAR Antibody-Polymeric Imidazoquinoline Complexes: Coordinated Targeting of PDL1 and Efficient TLR7/8 Activation in Intratumoral Dendritic Cells

Intratumoral dendritic cells (DCs) are pivotal in tumor treatment due to their immature and pro-tumoral state induced by the tumor microenvironment. Clinically, these immature DCs correlate with disease progression and recurrence, adversely affecting prognosis. Activation of DCs by the TLR7/8 agonist imidazoquinoline (IMDQ) has yielded promising results, but they are limited by systemic inflammation risks, and high programmed death ligand 1 (PDL1) expression on DCs impedes CD8+ T cell activity. Thus, the study introduces an antibody-polymeric IMDQ complex (αPDL1-PLG-IMDQ) with an ultrahigh drug-to-antibody ratio, where αPDL1 is conjugated to Fc-binding peptides on polymeric IMDQ. This complex targets high PDL1-expressing intratumoral DCs with high probability, inducing PDL1-mediated endocytosis to deliver IMDQ to TLR7/8 within endosomes, effectively activating DCs (CD11c+MHC II+: 2.33% versus 1.09%, CD11c+CD86+: 2.49% versus 1.00% on tumors compared to phosphate-buffered saline treatment) and priming T cells. It also blocks PDL1/PD1 interactions, enhancing tumor-specific T-cell activation and memory. Notably, αPDL1-PLG-IMDQ achieved a 97% tumor inhibition rate, prevented tumor regrowth in rechallenge experiments, and reduced lung metastases of tumors by 83%. These findings underscore its potential for intratumoral DC-targeted immunotherapy and novel systemic IMDQ and checkpoint inhibitor combinations.

The relationship between immune-related adverse events during ipilimumab monotherapy and survival outcomes among melanoma patients: A systematic review

BackgroundIpilimumab disinhibits immune system activity which results in the elimination of malignant cells. An unintended consequence of ipilimumab therapy is off-target immune-related adverse events (irAEs). It has therefore been proposed that the incidence of irAEs is a manifestation of treatment effectiveness. The objective of this systematic review is to examine the relationship between irAEs and survivability among melanoma patients administered ipilimumab monotherapy.MethodsA comprehensive search was conducted across several databases which yielded a total of 2381 studies. Clinical trials and prospective studies administering ipilimumab monotherapy to melanoma patients were included. Furthermore, there was no restriction placed on publication date. After screening, five studies were included for data extraction. The primary outcome of median overall survival (OS) and the secondary outcome of OS hazard ratio were extracted from the included studies.ResultsBased on qualitative analysis of the included studies, there seemed to be an association between the occurrence of non-lethal irAEs and improved survival outcomes among melanoma patients administered ipilimumab monotherapy. With that being said, the poorer survivability among patients who experienced high-grade irAEs may be the result of subsequent treatment discontinuation. Potential confounders such as corticosteroid use should be accounted for. Finally, landmark analyses may be conducted to account for immortal time bias.ConclusionsThe findings from this systematic review provide evidence suggesting that the incidence of irAEs is a marker of an improved anti-tumor response.

Deciphering T-cell exhaustion in the tumor microenvironment: paving the way for innovative solid tumor therapies

In solid tumors, the tumor microenvironment (TME) is a complex mix of tumor, immune, stromal cells, fibroblasts, and the extracellular matrix. Cytotoxic T lymphocytes (CTLs) constitute a fraction of immune cells that may infiltrate into the TME. The primary function of these T-cells is to detect and eliminate tumor cells. However, due to the immunosuppressive factors present in the TME primarily mediated by Myeloid-Derived Suppressor Cells (MDSCs), Tumor associated macrophages (TAMs), Cancer Associated Fibroblasts (CAFs) as well as the tumor cells themselves, T-cells fail to differentiate into effector cells or become dysfunctional and are unable to eliminate the tumor. In addition, chronic antigen stimulation within the TME also leads to a phenomenon, first identified in chronic lymphocytic choriomeningitis virus (LCMV) infection in mice, where the T-cells become exhausted and lose their effector functions. Exhausted T-cells (Tex) are characterized by the presence of remarkably conserved inhibitory receptors, transcription and signaling factors and the downregulation of key effector molecules. Tex cells have been identified in various malignancies, including melanoma, colorectal and hepatocellular cancers. Recent studies have indicated novel strategies to reverse T-cell exhaustion. These include checkpoint inhibitor blockade targeting programmed cell death protein 1 (PD-1), T-cell immunoglobulin and mucin-domain containing-3 (Tim-3), cytotoxic T-lymphocyte associated protein 4 (CTLA-4), or combinations of different immune checkpoint therapies (ICTs) or combination of ICTs with cytokine co-stimulation. In this review, we discuss aspects of T-cell dysfunction within the TME with a focus on T-cell exhaustion. We believe that gaining insight into the mechanisms of T-cell exhaustion within the TME of human solid tumors will pave the way for developing therapeutic strategies to target and potentially re-invigorate exhausted T-cells in cancer.

Nanomaterials-mediated adenosine pathway inhibition for strengthening cancer immunotherapy

Immunotherapy has developed into an attractive tumor treatment strategy. However, the existence of an immunosuppressive tumor microenvironment (ITME) greatly reduces the efficacy of immunotherapy. Adenosine (ADO) is one of the vital negative feedbacks in ITME, which inhibits antigen presentation and immune cell activation by binding to adenosine receptors (ADORs), thus tremendously suppressing immune response. Currently, the treatment effect of numerous inhibitors targeting the ADO pathway has been demonstrated in early clinical trials of various tumors. Nevertheless, the clinical application of these inhibitors is still plagued by diverse issues, such as short half-life, a single administration route, low bioavailability, etc. With the progress of nanotechnology, the delivery system of ADO inhibitors based on nanomaterials can solve the above problems. This review discusses the utilization of nanomaterials as a prospective method to inhibit ADO pathway and enhance immunotherapy outcomes. Specifically, the immunosuppressive mechanisms of ADO are summarized, and the corresponding intervention strategies are proposed. Then plentiful nanomaterials targeting the ADO pathway are highlighted, including phospholipids and polymers-based nanomaterials, mesoporous nanomaterials, biomimetic nanomaterials and metal-based nanomaterials. Finally, the outlook and challenges about nanomaterials-mediated ADO pathway inhibition were outlined, expecting to promote the clinical application of ADO inhibitor nanomedicines.

A Single-Cell Atlas of RNA Alternative Splicing in the Glioma-Immune Ecosystem

Single-cell analysis has refined our understanding of cellular heterogeneity in glioma, yet RNA alternative splicing (AS)-a critical layer of transcriptome regulation-remains underexplored at single-cell resolution. Here, we present a pan-glioma single-cell AS analysis in both tumor and immune cells through integrating seven SMART-seq2 datasets of human gliomas. Our analysis reveals lineage-specific AS across glioma cellular states, with the most divergent AS landscapes between mesenchymal- and neuronal-like glioma cells, exemplified by AS in TCF12 and PTBP2. Comparison between core and peripheral glioma cells highlights AS-redox co-regulation of cytoskeleton organization. Further analysis of glioma-infiltrating immune cells reveals potential isoform-level regulation of protein glycosylation in regulatory T cells and a link between MS4A7 AS in macrophages and clinical response to anti-PD-1 therapy. This study emphasizes the role of AS in glioma cellular heterogeneity, highlighting the importance of an isoform-centric approach to better understand the complex biological processes driving tumorigenesis.

PD-L1/PD-1 Expression in the Treatment of Oral Squamous Cell Carcinoma and Oral Potentially Malignant Disorders: An Overview of Reviews

Objective: In this overview, we present compelling evidence from multiple systematic reviews and meta-analyses (SRMAs) and examine the prognostic role of the PD-L1/PD-1 axis, as well as the potential of personalized treatment strategies targeting this axis, in patients with oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs). Methods: Six databases were searched to retrieve systematic review and meta-analysis studies. The population of interest was patients with OSCC and OPMDs in whom the expression of PD-L1 and PD-1 had been investigated. At least one of the following outcomes was reported, along with at least one clinicopathological feature: overall survival, disease-free survival, or disease-specific survival. All studies were assessed for risk of bias using the AMSTAR 2 tool. Results: A total of 195 studies were found through the initial search, and after duplicate removal, 97 studies were screened by title and abstract. Finally, five systematic reviews and meta-analysis studies fit our inclusion criteria and were included in this review. Conclusions: Based on two published systematic reviews, our study revealed a lack of evidence for the prognostic value of PD-L1 in improving overall survival in oral cancer patients. However, it showed a correlation with specific clinicopathological features such as sex, lymph node metastasis, and HPV status.

Ruxolitinib and oHSV combination therapy increases CD4 T cell activity and germinal center B cell populations in murine sarcoma

Malignant peripheral nerve sheath tumors (MPNSTs) are a highly aggressive neoplasm of the peripheral nervous system and are resistant to most conventional cancer therapies. We previously showed that pretreatment with ruxolitinib (RUX) enhanced the efficacy of oncolytic herpes simplex virus (oHSV) virotherapy in this murine sarcoma model. A low abundance of tumor-infiltrating leukocytes and limitations in conventional flow cytometry restrict analyses to a narrow subset of immune cells, potentially introducing a confirmation bias. To address these limitations, we developed a 46-color spectral flow cytometry panel for the detailed analysis of immune cell dynamics following repeated oHSV dosing. Beyond the cytotoxic T lymphocyte (CTL) and regulatory T cell (Treg) changes reported in our earlier studies, RUX+oHSV treatment modulates myeloid and other lymphoid compartments, including germinal center B cell populations with enhanced activation. RUX+oHSV therapy also increased cytokine-expressing CD4(+) populations, predominantly granzyme B(+) cytotoxic-like, interferon (IFN)-γ(+) T helper type 1 (Th1)-like, and interleukin (IL)-21(+) T follicular helper (Tfh)-like phenotypes, within the tumor infiltrates, suggestive of potential tertiary lymphoid structure development in the treated tumors. Here, we illustrate the utility of a high-dimensional spectral flow cytometry panel that permits simultaneous evaluation of intratumoral CD4/CD8 T cell, Treg, γδ-T cell, natural killer T (NKT) cell, B cell, NK cell, monocyte, macrophage, granulocyte, myeloid-derived suppressor cell (MDSC), and dendritic cell functional changes from RUX+oHSV-treated MPNSTs.

Fc-mediated immune stimulating, pro-inflammatory and antitumor effects of anti-HER2 IgE against HER2-expressing and trastuzumab-resistant tumors

BACKGROUND

Anti-human epidermal growth factor receptor 2 (HER2) IgG1-based antibody therapies significantly improve cancer prognosis, yet intrinsic or acquired resistance to fragment antigen-binding (Fab)-mediated direct effects commonly occurs. Most resistant tumors retain antigen expression and therefore remain potentially targetable with anti-HER2 therapies that promote immune-mediated responses. Tumor-antigen-specific IgE class antibodies can mediate powerful immune cell-mediated effects against different cancers and have been shown to activate IgE Fc receptor-expressing monocytes. We previously reported the engineering of a trastuzumab-equivalent anti-HER2 IgE antibody and showed early evidence of Fc-mediated cancer cell-targeting effects. In the present study, we evaluated the anti-tumoral functions of two anti-HER2 IgEs, trastuzumab and pertuzumab IgE.

METHODS

In vitro functionality of the two anti-HER2 antibodies was assessed by HER2 phosphorylation and ligand-independent viability assays, as well as basophil (RBL-SX38) degranulation, antibody-dependent cellular cytotoxicity/antibody-dependent cellular phagocytosis(ADCC/ADCP) assays and primary monocyte stimulation assays. The potential to trigger a hypersensitivity type I reaction was investigated using the basophil activation test (BAT). anti-tumoral efficacy was assessed in two humanized HER2+, trastuzumab-resistant models in vivo. Changes in the tumor microenvironment were assessed by flow cytometry or bulk RNA sequencing.

RESULTS

We demonstrate the anti-tumoral and immunostimulatory functions of two anti-HER2 IgEs derived from variable region sequences of the clinically available trastuzumab and pertuzumab IgG1 antibodies. IgE engagement of monocytes via the Fc region induced tumor cell cytotoxicity and a pro-inflammatory shift with upregulation of immune-stimulatory CD40, CD80 and CD86, and downregulation of scavenger CD163, cell surface molecules. This was accompanied by enhanced pro-inflammatory tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β cytokine production. The absence of basophil activation by anti-HER2 IgEs ex vivo in whole blood points to potentially safe administration in humans. In two trastuzumab-resistant HER2+ tumor xenograft models in immunodeficient mice reconstituted with human immune cells, the trastuzumab-equivalent anti-HER2 IgE restricted tumor growth. Treatment was associated with enriched classical (CD14+CD16-) monocyte and lower alternatively-activated (CD163+CD206+) macrophage infiltration, and higher densities of activated CD4+ (CD127loCD25hi) T cells and favorable effector T cell(Teff) to regulatory T cell (Treg) ratios in tumors.

CONCLUSION

Collectively, anti-HER2 IgE maintains Fab-mediated antitumor activity, induces Fc-mediated effects against HER2-expressing tumor cells, and stimulates remodeling of the immune microenvironment in tumors to promote pro-inflammatory cell phenotypes which could translate to improved outcomes for patients.

Pan-cancer characterization of m6A-mediated regulation of T cell exhaustion dynamics and clinical relevancies in human cancers

T cell exhaustion (TEX) is a major barrier to effective immunotherapy. The role of N6-methyladenosine (m6A) modification in regulating immune cell function has been recognized, but its impact on TEX dynamics across cancer types and clinical outcomes remains unclear. Here, we conducted a pan-cancer analysis integrating multi-omics data from cell lines, single-cell RNA sequencing, and pan-cancer and immunotherapy datasets to explore the dynamic interplay between m6A modification and TEX. We found that m6A modification influences key TEX-associated genes at both the cellular and single-cell levels, with distinct expression patterns across the exhaustion spectrum. Based on m6A-TEX interactions, three pan-cancer subtypes were identified, each with unique molecular profiles, immune phenotypes, and survival outcomes. The TexLm6AL subtype, characterized by low m6A activity and low TEX, correlated with high immune infiltration, increased cytolytic activity, and favorable survival, whereas the TexLm6AH and TexHm6AH subtypes with higher m6A activity were associated with poorer survival. Multivariate analysis confirmed the prognostic value of this classification independent of traditional clinical factors. Moreover, m6A-TEX crosstalk influenced responses to immune checkpoint blockade therapies. Our findings provide novel insights into the role of m6A in TEX regulation and underscore the potential of m6A regulators as biomarkers and therapeutic targets for advancing cancer immunotherapy.

The epigenetic hallmarks of immune cells in cancer

Targeting the dysregulation of epigenetic mechanisms in cancer has emerged as a promising therapeutic strategy. Although the significant rationale progress of epigenetic therapies in blocking cancer cells, how epigenetic regulation shapes tumor microenvironment (TME) and establishes antitumor immunity remains less understood. Recent study focus has been put on the epigenetic-mediated changes in the fate of immune cells, including the differentiation, expansion, recruitment, functionalization, and exhaustion of T cells, natural killer (NK) cells, tumor-associated macrophages (TAMs), dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), and B cells within the TME. Here, we review the latest molecular and clinical insights into how DNA modifications, histone modification, and epitranscriptome-related regulations shape immune cells of various cancers. We also discuss opportunities for leveraging epigenetic therapies to improve cancer immunotherapies. This review provides the epigenetic foundations of cancer immunity and proposes the future direction of combination therapies.

Characterization of Exhausted T Cell Signatures in Pan-Cancer Settings

T cells play diverse roles in cancer immunology, acting as tumor suppressors, cytotoxic effectors, enhancers of cytotoxic T lymphocyte responses and immune suppressors; providing memory and surveillance; modulating the tumor microenvironment (TME); or activating innate immune cells. However, cancer cells can disrupt T cell function, leading to T cell exhaustion and a weakened immune response against the tumor. The expression of exhausted T cell (Tex) markers plays a pivotal role in shaping the immune landscape of multiple cancers. Our aim was to systematically investigate the role of known T cell exhaustion (Tex) markers across multiple cancers while exploring their molecular interactions, mutation profiles, and potential implications for immunotherapy. The mRNA expression profile of six Tex markers, LAG-3, PDCD1, TIGIT, HAVCR2, CXCL13, and LAYN was investigated in pan-cancer. Utilizing data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), The Cancer Proteome Atlas (TCPA), and other repositories, we characterized the differential expression of the Tex markers, their association with the patients' survival outcome, and their mutation profile in multiple cancers. Additionally, we analyzed the effects on cancer-related pathways and immune infiltration within the TME, offering valuable insights into mechanisms of cancer immune evasion and progression. Finally, the correlation between their expression and sensitivity to multiple anti-cancer drugs was investigated extensively. Differential expression of all six markers was significantly associated with KIRC and poor prognosis in several cancers. They also played a potential activating role in apoptosis, EMT, and hormone ER pathways, as well as a potential inhibitory role in the DNA damage response and RTK oncogenic pathways. Infiltration of different immune cells was also found to be associated with the expression of the Tex-related genes in most cancer types. These findings underline that the reviving of exhausted T cells can be used to enhance the efficacy of immunotherapy in cancer patients.

A functional single-cell metabolic survey identifies Elovl1 as a target to enhance CD8+ T cell fitness in solid tumours

Reprogramming T cell metabolism can improve intratumoural fitness. By performing a CRISPR/Cas9 metabolic survey in CD8+ T cells, we identified 83 targets and we applied single-cell RNA sequencing to disclose transcriptome changes associated with each metabolic perturbation in the context of pancreatic cancer. This revealed elongation of very long-chain fatty acids protein 1 (Elovl1) as a metabolic target to sustain effector functions and memory phenotypes in CD8+ T cells. Accordingly, Elovl1 inactivation in adoptively transferred T cells combined with anti-PD-1 showed therapeutic efficacy in resistant pancreatic and melanoma tumours. The accumulation of saturated long-chain fatty acids in Elovl1-deficient T cells destabilized INSIG1, leading to SREBP2 activation, increased plasma membrane cholesterol and stronger T cell receptor signalling. Elovl1-deficient T cells increased mitochondrial fitness and fatty acid oxidation, thus withstanding the metabolic stress imposed by the tumour microenvironment. Finally, ELOVL1 in CD8+ T cells correlated with anti-PD-1 response in patients with melanoma. Altogether, Elovl1 targeting synergizes with anti-PD-1 to promote effective T cell responses.

Neoadjuvant chemoradiotherapy up-regulates PD-L1 in radioresistant colorectal cancer

Background

Combining radiotherapy (RT) with immune checkpoint inhibitors (ICIs) is a promising strategy that can enhance the therapeutic efficacy of ICIs. However, little is known about RT-induced changes in the expression of immune checkpoints, such as PD-L1, and their clinical implications in colorectal cancer (CRC). This study aimed to investigate the association between responsiveness to RT and changes in PD-L1 expression in human CRC tissue and cell lines.

Methods

Tissue specimens from preoperative biopsy via sigmoidoscopy and surgical resection were obtained from 24 patients with locally advanced rectal cancer (LARC) who underwent neoadjuvant chemoradiation therapy (CRT) between August 2016 and December 2017. Immunohistochemistry for PD-L1 in formalin-fixed paraffin-embedded tissue was performed from the endoscopic biopsy and surgical specimens. RNA sequencing was performed using 11 pairs of human LARC tissues before and after irradiation. After exposing human CRC cells to radiation, we investigated changes in the expression levels of PD-L1 and its regulatory signaling pathways.

Results

Patients were classified by tumor regression grade into responders (grade 2; 9 patients, 37.5 %) and non-responders (grades 3, 4, or 5; 15 patients, 62.5 %). In the non-responder group, 13 patients had low PD-L1 expression, but neoadjuvant CRT increased PD-L1 expression in 7 patients (53.9 %) (McNemar's test, p=0.034). CRT up-regulated PD-L1 in non-responder LARC tissues. Similarly, radiation increased PD-L1 in radioresistant DLD-1 cells more than in radiosensitive HCT116 cells, also affecting PD-L1-regulating genes and immune checkpoints in CRC cells. Conventional fractionated radiation treatment further increased PD-L1 in DLD-1 cells compared to HCT116 cells.

Conclusions

This study demonstrated that radiation induces an increase in PD-L1 expression, which is more pronounced in radioresistant CRC, proving the theoretical framework for a combined treatment strategy with a PD-L1 blockade for locally advanced rectal cancer.

Effect of boswellic acids on the expression of PD-1 and TIGIT immune checkpoints on activated human T cells

Boswellic acids (BAs) have been documented as anti-inflammatory agents with the potential to regulate immune responses. However, their impacts on the expression level of immune checkpoint (IC) molecules in T cells have never been reported. By using flow cytometric assays, we investigated whether BAs extracted from Boswellia sacra (B. sacra) have any potential effects on the expression of PD-1 and TIGIT immune checkpoints (ICs) on activated T cells in vitro. Interestingly β-BA at a concentration of 50 μM significantly reduced the expression of PD-1 and TIGIT on both activated CD4+ and CD8+ T cells without any cytotoxicity. Additionally, β-KBA significantly reduced the percentages of CD4+PD-1+ and CD8+TIGIT+ T cells at 50 μM concentration. Furthermore, a significant reduction in CD4+PD-1+ T cells was observed following treatment with a lower concentration (25 μM) of β-AKBA. These findings show that BA compounds have the ability to reduce the expression of PD-1 and TIGIT in stimulated human T cells, which might play critical roles in reinvigorating exhausted T cells, indicating their potentials in immunosuppressed disease settings such as cancers and infections. This study is the first to investigate the effects of these compounds on the expression of immune checkpoints in human T cells. Clearly, further investigations are required to assess the mechanism of action of these compounds on ICs, and their efficacy as therapeutic agents in different diseases.

LOX+ iCAFs in HNSCC have the potential to predict prognosis and immunotherapy responses revealed by single cell RNA sequencing analysis

Carcinoma-associated fibroblasts (CAFs) exhibit significant heterogeneity and are closely associated with progression, resistance to anticancer therapies, and poor prognosis in head and neck squamous cell carcinoma (HNSCC). However, the specific functional role of CAFs in HNSCC has been inadequately explored. In this study, we utilized a single-cell RNA sequencing dataset from HNSCC (GSE103322) to recluster CAFs via the Seurat pipeline. On the basis of the reported markers, we identified two CAF subtypes, LOX-myCAFs and LOX + iCAFs, and generated signature markers for each. Through unsupervised consensus clustering, we identified and characterized two molecular subtypes of HNSCC-TCGA, each exhibiting distinct dysregulated cancer hallmarks, immunological tumor microenvironments, and stemness characteristics. The robustness of the LOX + iCAF-related signature clustering, particularly in terms of prognosis and prediction of immunotherapeutic response, was validated in an ANOVA cohort via a GEO dataset (GSE159067) consisting of 102 HNSCC patients. A positive correlation was validated between the expression of LOX and that of CD86, a marker of M1 macrophage polarization. Further experiments involving the coculture of conditioned medium derived from LOX-silenced CAFs with CAL-27 and UM-SCC-1 cell lines revealed that LOX silencing led to decreased proliferation and migration of these cancer cells, which was mediated by epithelial-mesenchymal transition (EMT) through IL-34- induced CSF1R/Akt signaling. In summary, our single-cell and bulk RNA sequencing analyses revealed a LOX + iCAF-related signature that can predict the prognosis and response to immunotherapy in HNSCC patients. Additionally, the LOX gene was identified as a promising therapeutic target for HNSCC treatment.

The Emerging Role of CD8+ T Cells in Shaping Treatment Outcomes of Patients with MDS and AML

CD8+ T cells are critical players in anti-tumor immunity against solid tumors, targeted by immunotherapies. Emerging evidence suggests that CD8+ T cells also play a crucial role in anti-tumor responses and determining treatment outcomes in hematologic malignancies like myelodysplastic neoplasms (MDS) and acute myeloid leukemia (AML). In this review, we focus on the implication of CD8+ T cells in the treatment response of patients with MDS and AML. First, we review reported studies of aberrant functionality and clonality of CD8+ T cells in MDS and AML, often driven by the immunosuppressive bone marrow microenvironment, which can hinder effective antitumor immunity. Additionally, we discuss the potential use of CD8+ T cell subpopulations, including memory and senescent-like subsets, as predictive biomarkers for treatment response to a variety of treatment regimens, such as hypomethylating agents, which is the standard of care for patients with higher-risk MDS, and chemotherapy which is the main treatment of patients with AML. Understanding the multifaceted role of CD8+ T cells and their interaction with malignant cells in MDS and AML will provide useful insights into their potential as prognostic/predictive biomarkers, but also uncover alternative approaches to novel treatment strategies that could reshape the therapeutic landscape, thus improving treatment efficacy, aiding in overcoming treatment resistance and improving patient survival in these challenging myeloid neoplasms.

Spatial transcriptomics-aided localization for single-cell transcriptomics with STALocator

Single-cell RNA-sequencing (scRNA-seq) techniques can measure gene expression at single-cell resolution but lack spatial information. Spatial transcriptomics (ST) techniques simultaneously provide gene expression data and spatial information. However, the data quality of the spatial resolution or gene coverage is still much lower than the quality of the single-cell transcriptomics data. To this end, we develop a ST-Aided Locator for single-cell transcriptomics (STALocator) to localize single cells to corresponding ST data. Applications on simulated data showed that STALocator performed better than other localization methods. When applied to the human brain and squamous cell carcinoma data, STALocator could robustly reconstruct the relative spatial organization of critical cell populations. Moreover, STALocator could enhance gene expression patterns for Slide-seqV2 data and predict genome-wide gene expression data for fluorescence in situ hybridization (FISH) and Xenium data, leading to the identification of more spatially variable genes and more biologically relevant Gene Ontology (GO) terms compared with the raw data. A record of this paper's transparent peer review process is included in the supplemental information.

Scalable intracellular delivery via microfluidic vortex shedding enhances the function of chimeric antigen receptor T-cells

Adoptive chimeric antigen receptor T-cell (CAR-T) therapy is transformative and approved for hematologic malignancies. It is also being developed for the treatment of solid tumors, autoimmune disorders, heart disease, and aging. Despite unprecedented clinical outcomes, CAR-T and other engineered cell therapies face a variety of manufacturing and safety challenges. Traditional methods, such as lentivirus transduction and electroporation, result in random integration or cause significant cellular damage, which can limit the safety and efficacy of engineered cell therapies. We present hydroporation as a gentle and effective alternative for intracellular delivery. Hydroporation resulted in 1.7- to 2-fold higher CAR-T yields compared to electroporation with superior cell viability and recovery. Hydroporated cells exhibited rapid proliferation, robust target cell lysis, and increased pro-inflammatory and regulatory cytokine secretion in addition to improved CAR-T yield by day 5 post-transfection. We demonstrate that scaled-up hydroporation can process 5 × 108 cells in less than 10 s, showcasing the platform as a viable solution for high-yield CAR-T manufacturing with the potential for improved therapeutic outcomes.

First-in-human evaluation of memory-like NK cells with an IL-15 super-agonist and CTLA-4 blockade in advanced head and neck cancer

BACKGROUND

Cytokine induced memory-like natural killer (CIML NK) cells combined with an IL-15 super-agonist (N-803) are a novel modality to treat relapsed/refractory head and neck cancer.

METHODS

We report data from a phase I trial of haploidentical CIML NK cells combined with N-803 with or without ipilimumab (IPI) in relapsed/refractory head and neck cancer patients after a median of 6 prior lines of therapy. The trial adhered to a 3 + 3 dose de-escalation design, with primary endpoint being safety. High-resolution immunophenotypic and transcriptional profiling characterized the NK cells and their interacting partners in vivo.

RESULTS

The primary safety endpoint was established, with dose-limiting toxicity in 1/10 patients. A transient disease control rate correlated with donor NK cell expansion, the latter occurring irrespective of IPI. The combination of CIML NK cells with N-803 and IPI was associated with increased early NK cell proliferation, contraction of Treg: Tcon, rapid recovery of recipient CD8+ T cells, and subsequent accelerated rejection of donor NK cells.

CONCLUSIONS

CIML NK cells combined with N-803 and ipilimumab to treat head and neck cancer is safe, and associated with a more proliferative NK cell phenotype. However, the combination leads to reduced HLA mismatched NK cell persistence, resulting in an important limitation affecting NK cell combination therapies in clinical trials. These results inform evaluation of CIML NK therapy for advanced malignancies, with considerations for combination with IPI.

TRIAL REGISTRATION

NCT04290546.

One-carbon metabolism is distinct metabolic signature for proliferative intermediate exhausted T cells of ICB-resistant cancer patients

One-carbon metabolism (1CM) has been reported to promote cancer progression across various malignancies. While 1CM is critical for cell proliferation by enhancing nucleotide synthesis, its physiological roles within different cell types in the tumor immune microenvironment (TIME) still remain unclear. In this study, we analyzed bulk-RNA sequencing and single-cell RNA sequencing (scRNA-seq) data from lung adenocarcinoma (LUAD) patients to elucidate the functional roles of 1CM within the TIME. Moreover, we examined scRNA-seq data from patients treated with immunotherapy across various cancers, including LUAD, glioblastoma, renal cell carcinoma, colorectal cancer, and triple-negative breast cancer. Compared to other cell types, 1CM gene profiles are significantly enriched in a specific subset of T cells. Intriguingly, these high-1CM T cells are identified as proliferative intermediate exhausted T cells (Texint). Furthermore, these proliferative Texint received the most robust CD137 signaling. Consistently, analysis of scRNA-seq data from LUAD patients undergoing anti-PD1 immunotherapy demonstrated that proliferative Texint exhibited higher 1CM scores and increased CD137 signaling. This observation was particularly pronounced in non-responders to immunotherapy, where the Texint population was significantly expanded. We further established that 1CM is a prominent signaling pathway in proliferative Texint in patients resistant to immunotherapy across multiple cancer types. Collectively, we identify CD137 signaling as a distinctive pathway in proliferative Texint of LUAD patients who do not respond to immunotherapy. These findings propose that targeting 1CM may represent a novel therapeutic strategy to enhance the efficacy of immunotherapy by mitigating Texint proliferation in diverse cancers.

Extracellular Vesicle-Based Strategies for Tumor Immunotherapy

Immunotherapy is one of the most promising approaches for cancer management, as it utilizes the intrinsic immune response to target cancer cells. Normally, the human body uses its immune system as a defense mechanism to detect and eliminate foreign objects, including cancer cells. However, cancers develop a 'switch off' mechanism, known as immune checkpoint proteins, to evade immune surveillance and suppress immune activation. Therefore, significant efforts have been made to develop the strategies for stimulating immune responses against cancers. Among these, the use of extracellular vesicles (EVs) to enhance the anti-tumor immune response has emerged as a particularly promising approach in cancer management. EVs possess several unique properties that elevate the potency in modulating immune responses. This review article provides a comprehensive overview of recent advances in this field, focusing on the strategic usage of EVs to overcome tumor-induced immune tolerance. We discuss the biogenesis and characteristics of EVs, as well as their potential applications in medical contexts. The immune mechanisms within the tumor microenvironment and the strategies employed by cancers to evade immune detection are explored. The roles of EVs in regulating the tumor microenvironment and enhancing immune responses for immunotherapy are also highlighted. Additionally, this article addresses the challenges and future directions for the development of EV-based nanomedicine approaches, aiming to improve cancer immunotherapy outcomes with greater precision and efficacy while minimizing off-target effects.

Pretreatment nutritional indices are associated with survival and T-cell exhaustion in recurrent or metastatic oral squamous cell carcinoma patients treated with immune checkpoint inhibitors: a retrospective cohort study

Pretreatment immune dynamics and nutritional status are important predictors of survival outcomes in various malignancies. This study was performed to evaluate the relationships between survival outcomes and the pretreatment nutritional indices - Onodera's prognostic nutritional index (OPNI) and neutrophil-to-lymphocyte ratio (NLR) - in 42 patients with recurrent or metastatic oral squamous cell carcinoma (OSCC) who underwent treatment with immune checkpoint inhibitors (ICI). Additionally, the relationships between these nutritional indices and T-cell exhaustion in the peripheral blood of the patients were analysed. As a result, the Kaplan-Meier method revealed that lower OPNI was significantly associated with poorer overall survival (OS) and progression-free survival (PFS) (both P < 0.001). Likewise, the results of the multivariate analysis showed that a low OPNI was independently associated with poor 5-year OS (hazard ratio 4.36, P = 0.008) and PFS (hazard ratio 4.04, P = 0.010). Patients with a low OPNI had a significantly higher frequency of PD-1+ CD8+ T-cells than those with a high OPNI (P = 0.009). These findings demonstrate that pretreatment OPNI is a valuable independent prognostic indicator of OS and PFS in OSCC patients following treatment with ICI. The OPNI might reflect T-cell exhaustion in the peripheral blood of OSCC patients.

Harnessing extracellular vesicle-mediated crosstalk between T cells and cancer cells for therapeutic applications

Small extracellular vesicles (EVs) are a diverse group of lipid-based particles that are ≤200 nm in diameter and contain an aqueous core. EVs have been shown to mediate intercellular communications between a wide array of immune cells; the downstream effects are diverse and have potential implications for the development of novel immunotherapeutic treatments. Despite a high volume of studies addressing the role EVs play in the immune system, our understanding of the crosstalk between T cells and cancer cells remains limited. Here, we discuss how EVs derived from cancer cells modulate T cell functions and conversely, how T cell derived EVs are crucial in modulating adaptive immune functions. In the context of cancer, tumor derived EVs (TD-EVs) halt T cell-mediated immunity by interfering with effector functions and enhancing regulatory T cell (Treg) functions. In contrast, EVs derived from effector T cells can serve to stimulate anticancer immunity, curbing metastasis and tumor growth. These findings highlight important aspects of how EVs can both mediate the therapeutic effects of T cells as well as impair T cell-mediated immunity. This calls for a deeper understanding of EV-mediated effects in order to advance them as next-generation therapeutics and nanocarriers.

Comprehensive Analysis of Granzymes and Perforin Family Genes in Multiple Cancers

Background/Objectives: Cancer remains a significant global health concern, with immunotherapies emerging as promising treatments. This study explored the role of perforin-1 (PRF1) and granzymes A, B and K (GZMA, GZMB and GZMK) in cancer biology, focusing on their impact on tumor cell death and immune response modulation. Methods: Through a comprehensive genomic analysis across various cancer types, we explored the differential expression, mutation profiles and methylation patterns of these genes, providing insights into their potential as therapeutic targets. Furthermore, we investigated their association with immune cell infiltration and pathway activation within the tumor microenvironment in each tumor type. Results: Our findings revealed distinct expression patterns and prognostic implications for PRF1, GZMA, GZMB and GZMK across different cancers, highlighting their multifaceted roles in tumor immunity. We found increased immune infiltration across all tumor types and significant correlations between the genes of interest and cytotoxic T cells, as well as the most significant survival outcomes in breast cancer. We also show that granzymes and perforin-1 are significantly associated with indicators of immunosuppression and T cell dysfunction within patient cohorts. In skin melanoma, glioblastoma, kidney and bladder cancers, we found significant correlations between the genes of interest and patient survival after receiving immune-checkpoint inhibition therapy. Additionally, we identified potential associations between the mRNA expression levels of these genes and drug sensitivity. Conclusions: Overall, this study enhances our understanding of the molecular mechanisms underlying tumor immunity and provides valuable insights into the potential therapeutic implications of PRF1, GZMA, GZMB and GZMK in cancer treatment.

Brd7 loss reawakens dormant metastasis initiating cells in lung by forging an immunosuppressive niche

Metastasis in cancer is influenced by epigenetic factors. Using an in vivo screen, we demonstrate that several subunits of the polybromo-associated BAF (PBAF) chromatin remodeling complex, particularly Brd7, are required for maintaining breast cancer metastatic dormancy in the lungs of female mice. Brd7 loss induces metastatic reawakening, along with modifications in epigenomic landscapes and upregulated oncogenic signaling. Breast cancer cells harboring Brd7 inactivation also reprogram the surrounding immune microenvironment by downregulating MHC-1 expression and promoting a pro-metastatic cytokine profile. Flow cytometric and single-cell analyses reveal increased levels of pro-tumorigenic inflammatory and transitional neutrophils, CD8+ exhausted T cells, and CD4+ stress response T cells in lungs from female mice harboring Brd7-deficient metastases. Finally, attenuating this immunosuppressive milieu by neutrophil depletion, neutrophil extracellular trap (NET) inhibition, or immune checkpoint therapy abrogates metastatic outgrowth. These findings implicate Brd7 and PBAF in triggering metastatic outgrowth in cancer, pointing to targetable underlying mechanisms involving specific immune cell compartments.

The possible anti-tumor effects of regulatory T cells plasticity / IL-35 in the tumor microenvironment of the major three cancer types

T lymphocytes are among the immunological cells that make up the tumor microenvironment (TME), and they are essential in the growth of tumors and anti-tumor reactions. Regulatory T cells (Treg cells) are a subset of CD4+ T cells in the immune system that suppress the immune system. They are distinguished by their expression of the master transcription factor forkhead box protein P3 (FOXP3). Furthermore, Treg cells are essential for maintaining immunological homeostasis, inhibiting inflammation, and maintaining self-tolerance. In a variety of malignancies within the TME, Treg cells demonstrate notable flexibility and functional diversity. Highly plastic Treg cells can change into Th-like Treg cells in specific circumstances, which allow them to secrete particular pro-inflammatory cytokines. Interleukin 35 (IL-35) is a part of the immunosuppressive cytokines that belong to the IL-12 family. Treg cells release IL-35, which was elevated in the peripheral blood and TME of numerous cancer patients, implying that IL-35 in the TME may be an intriguing target for cancer therapy. In cancer, IL-35 is a two-edged sword; it promotes tumorigenicity in cancer cells while shielding them from apoptosis. Nonetheless, other investigations have mentioned its conflicting effects on cancer prevention. Herein, we provide an updated understanding of the critical mechanisms behind the anticancer immunity mediated by Treg cells plasticity, the role of IL-35, and tactics to strengthen the immune response against malignancies, outlining major clinical trials that used Treg cells/IL-35 therapies in the three main cancer types (lung, breast, and colorectal cancers).

Spatial‒temporal heterogeneities of liver cancer and the discovery of the invasive zone

Solid tumours are intricate and highly heterogeneous ecosystems, which grow in and invade normal organs. Their progression is mediated by cancer cells' interaction with different cell types, such as immune cells, stromal cells and endothelial cells, and with the extracellular matrix. Owing to its high incidence, aggressive growth and resistance to local and systemic treatments, liver cancer has particularly high mortality rates worldwide. In recent decades, spatial heterogeneity has garnered significant attention as an unfavourable biological characteristic of the tumour microenvironment, prompting extensive research into its role in liver tumour development. Advances in spatial omics have facilitated the detailed spatial analysis of cell types, states and cell‒cell interactions, allowing a thorough understanding of the spatial and temporal heterogeneities of tumour microenvironment and informing the development of novel therapeutic approaches. This review illustrates the latest discovery of the invasive zone, and systematically introduced specific macroscopic spatial heterogeneities, pathological spatial heterogeneities and tumour microenvironment heterogeneities of liver cancer.

Immunosenescence and age-related immune cells: causes of age-related diseases

Immunosenescence is a weakening of the immune system due to aging, characterized by changes in immune cells and dysregulated immune function. Age-related immune cells are increasing with aging. They are associated with chronic prolonged inflammation, causing tissue dysfunction and age-related diseases. Here, we discuss increased pro-inflammatory activity of aged macrophages, accumulation of lymphocytes with an age-associated phenotype, and specific alterations in both functions and characteristics of these immune cells. These cellular changes are associated with development of age-related diseases. Additionally, we reviewed various therapeutic strategies targeting age-related immunosenescence, providing pathways to mitigate effects of age-related diseases.

The Novel Oncolytic Herpes Simplex Virus Type-1 (HSV-1) Vaccine Strain VC2 Constitutively Expressing GM-CSF Causes Increased Intratumoral T Cell Infiltration and Inhibition of Tumor Metastasis in the 4T1/Balb/c Mouse Model of Stage Four Breast Cancer

Oncolytic virotherapy (OVT) aims to disrupt the tumor microenvironment and provide a unique therapeutic approach against solid tumors. Herpes simplex virus type-1 (HSV-1) has shown strong promise for treating various solid tumors and has been approved to treat melanoma and glioma in human patients. Previously, we reported the generation of an engineered HSV-1 vaccine strain VC2, which has shown exceptional promise as an oncolytic and immunotherapeutic virus. In the present work, we engineered VC2 to constitutively express the murine granulocyte-macrophage colony-stimulating factor (GM-CSF) gene inserted in place of HSV-1 Glycoprotein C (gC). We tested the efficacy of VC2-GMCSF for its ability to generate antitumor response in the 4T1 stage four metastatic breast cancer mouse model. GM-CSF expression enhanced VC2 viral replication and infectious virus production. Tumors formed after 7 days of engraftment in the mammary fat pad of Balb/CJ mice were treated by injecting ~5 × 104 plaque forming units (PFU) of VC2/VC2-GMCSF once. Intratumor treatment did not appreciably reduce average primary tumor sizes. However, metastatic foci were significantly reduced in mice lungs treated with VC2-GMCSF compared to VC2 or mock treatment. VC2-GMCSF intratumoral treatment induced a stronger intratumor T cell infiltration but not an increased cytotoxic activity. A significant T cell infiltration was observed in the metastatic areas in VC2-GMCSF treated animals, which was associated with reduced pro-tumor marker PDL1 and VEGF gene expression. These results show that constitutive expression of GM-CSF enhanced the overall efficacy of VC2 for OVT. VC2-GMCSF holds promise as oncolytic and immunotherapeutic virotherapy for breast and other cancers.

An in-depth understanding of the role and mechanisms of T cells in immune organ aging and age-related diseases

T cells play a critical and irreplaceable role in maintaining overall health. However, their functions undergo alterations as individuals age. It is of utmost importance to comprehend the specific characteristics of T-cell aging, as this knowledge is crucial for gaining deeper insights into the pathogenesis of aging-related diseases and developing effective therapeutic strategies. In this review, we have thoroughly examined the existing studies on the characteristics of immune organ aging. Furthermore, we elucidated the changes and potential mechanisms that occur in T cells during the aging process. Additionally, we have discussed the latest research advancements pertaining to T-cell aging-related diseases. These findings provide a fresh perspective for the study of T cells in the context of aging.

PD-L1-CD80 interactions are required for intracellular signaling necessary for dendritic cell migration

Programmed cell death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) interactions are targets for immunotherapies aimed to reinvigorate T cell function. Recently, it was documented that PD-L1 regulates dendritic cell (DC) migration through intracellular signaling events. In this study, we find that both preclinical murine and clinically available human PD-L1 antibodies limit DC migration. We show that cis interactions between PD-L1 and CD80 are critical for promoting migration and define specific regions within these proteins necessary for migration. Furthermore, we demonstrate that αPD-L1 significantly impedes DC migration in a B16 melanoma tumor model. Last, we outline how blocking cis PD-L1:CD80 interactions or mutation of the intracellular domain of PD-L1, in an imiquimod-induced murine model of psoriasis, limits DC migration to the lymph node, decreases interleukin-17 production by CD4+ T cells in the lymph node, and reduces epidermal thickening. Therefore, PD-L1 and CD80 interactions are important regulators of DC migration to the draining lymph node.