Background: Breast cancer (BrCa) patients with tumors expressing high interleukin-6 (IL6) levels have poor clinical outcomes. In BrCa, altered occupancy of CCCTC-binding factor (CTCF) within its DNA binding sites deregulates the expression of its targeted genes. In this study, we investigated whether CTCF contributes to the altered IL6 expression in BrCa. Methods/Results: We performed CTCF gain- and loss-of-function assays in BrCa cell lines and observed an inverse correlation between CTCF and IL6 expression levels. To understand how CTCF negatively regulates IL6 gene expression, we performed luciferase gene reporter assays, site-directed mutagenesis assays, and chromatin immunoprecipitation assays. Our findings revealed that CTCF interacted with the IL6 promoter, a form of regulation disrupted in a CpG methylation-independent fashion in MDA-MB-231 and Tamoxifen-resistant MCF7 cells. Data from TCGA and GEO databases allowed us to explore the clinical implications of our results. An inverse correlation between CTCF and IL6 expression levels was seen in disease-free survival BrCa patients but not in patients who experienced cancer recurrence. Conclusions: Our findings provide evidence that the CTCF-mediated negative regulation of the IL6 gene is lost in highly tumorigenic BrCa cells.

We investigated the impact of rheumatoid arthritis (RA) associated cytokines and standard of care (SOC) RA therapeutics on immune checkpoint receptor (IR) expression on T cells to gain insights to disease pathology and therapeutic avenues.

We assessed IR expression by flow cytometry on T cell receptor activated T cells cultured in the presence of exogenously added single cytokines or RA patient synovial fluid. We also assessed RA synovial fluid stimulated samples in the presence of various single cytokine neutralizing antibodies or SOC therapeutics, including glucocorticoids, TNF, IL-6 receptor and JAK inhibitors. In addition to IR expression, we measured the impact on cytokine secretion profiles.

RA-associated cytokines modulated IR expression, suggesting a role for these cytokines in regulation of disease pathology. By dissecting the influence of various inflammatory drivers within the RA inflammatory milieu, we discovered distinct regulation of IR expression by various cytokines including IL-10, IFNα/β, and TNF. Specifically, increased expression of TIM-3, PD-1, LAG-3 and CD28 in response to RA synovial fluid was driven by key cytokines including IL-6, IL-10, IL-12, IFNs, and TNF. In addition, SOC RA therapeutics such as glucocorticoids and TNF inhibitors modulated IR and cytokine expression in the presence of RA synovial fluid.

This study points to an important and intricate relationship between cytokines and IRs in shaping immune responses in autoimmune pathology. The modulation of IR expression by RA-associated cytokines and SOC therapeutics provides new insights for the use of targeted treatments in managing RA pathology.

Selinexor (SEL) is a nuclear exportin 1 inhibitor that blocks the transport of nuclear proteins, including tumor suppressors, to the cytoplasm. Preclinical data suggest that the combination of SEL with checkpoint blockade may result in improved response to immunotherapy.

NCT02419495 was a multiarm phase IB study of SEL in combination with other standard regimens in patients with advanced malignancies. Arm M utilized twice weekly oral SEL and intravenous nivolumab (NIVO). Arm N utilized weekly oral SEL with NIVO plus ipilimumab (IPI). The primary objective of this study was to evaluate the safety of SEL + NIVO and SEL + NIVO+IPI. Secondary objectives included determining the objective response rate (ORR) and progression-free survival (PFS).

Twenty-nine patients were enrolled in the study, of which 26 (90%) had clear cell RCC (ccRCC). Most patients (72%, n = 21) had prior systemic therapies. All patients (100%) developed at least one treatment-emergent adverse event, and 93% had a treatment-related adverse event (TRAE). Grade ≥ 3 TRAE occurred in 31% of patients, including 10% with hyponatremia, 7% with neutropenia, and 7% with thromboembolic events. At a median follow-up of 12.4 months, the ORR in 27 patients evaluable for response was 19% (n = 5). An additional 17 patients (63%) had stable disease (SD) as the best response. The median PFS for the overall cohort was 14.5 months (95% CI 5.2-17.4 months; SEL + NIVO+IPI: 12.2 months, SEL + NIVO: 14.5 months). The median overall survival was 27.8 months (95% CI 15.3-32.5; SEL + NIVO+IPI: unreached, SEL + NIVO: 21.3 months).

SEL in combination with NIVO or NIVO+IPI had a potentially favorable safety profile and showed modest clinical activity in patients with advanced renal cell carcinoma.

This clinical trial was registered on clinicaltrials.gov (NCT02419495).

Achieving the precise targeting of lentiviral vectors (LVs) to specific cell populations is crucial for effective gene therapy, particularly in cancer treatment where the modulation of the tumor microenvironment can enhance anti-tumor immunity. Programmed cell death protein 1 (PD-1) is overexpressed on activated tumor-infiltrating T lymphocytes, including regulatory T cells that suppress immune responses via FOXP3 expression. We developed PD1-targeted LVs by incorporating the anti-PD1 nanobody nb102c3 into receptor-blinded measles virus H and VSV-Gmut glycoproteins. We assessed the retargeting potential of nb102c3 and evaluated transduction efficiency in activated T lymphocytes. FOXP3 expression was suppressed using shRNA delivered by these LVs. Our results demonstrate that PD1-targeted LVs exerted pronounced tropism towards PD1+ cells, enabling the selective transduction of activated T lymphocytes while sparing naive T cells. The suppression of FOXP3 in Tregs reduced their suppressive activity. PD1-targeted glycoprotein H provided greater specificity, whereas the VSV-Gmut, together with the anti-PD1 pseudoreceptor, achieved higher viral titers but was less selective. Our study demonstrates that PD1-targeted LVs may offer a novel strategy to modulate immune responses within the tumor microenvironment with the potential for developing new therapeutic strategies aimed at enhancing anti-tumor immunity.

Colorectal cancer (CRC) is a prevalent malignancy with a high mortality rate. Tumor-infiltrating lymphocytes (TILs) play a crucial role in the immune response against tumors. Programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) are key immune checkpoints regulating T cells in the tumor microenvironment. This study aimed to assess the relationships among PD-1 expression on TILs, PD-L1 expression in tumors, and TIL grading in colorectal adenocarcinoma.

A cross-sectional design was employed to analyze 130 colorectal adenocarcinoma samples. The expression of PD-1 and PD-L1 was assessed through immunohistochemistry. A semi-quantitative scoring system was applied. Statistical analysis with the chi-square test was performed to explore correlations, with the data analyzed in SPSS version 27.

PD-1 expression on TILs significantly correlated with a higher TIL grading (p < 0.001), while PD-L1 expression in tumors showed an inverse correlation with TIL grading (p < 0.001).

The expression of PD-1 on TILs and PD-L1 on tumor cells correlated significantly with the grading of TILs in colorectal adenocarcinoma. This finding shows potential as a predictive biomarker for PD-1/PD-L1 blockade therapy. Further studies are needed to strengthen these results.

Intraepithelial lymphocytes (IELs) expressing the TCRγδ survey the intestinal epithelium to limit the invasion of microbial pathogens. The production of type I IFN is a central component of an antiviral immune response, yet how these proinflammatory cytokines contribute to γδ IEL effector function remains unclear. Based on the unique activation status of IELs and their ability to bridge innate and adaptive immunity, we investigated the extent to which type I IFN signaling modulates γδ IEL function. Using an ex vivo culture model, we find that type I IFN alone is unable to drive IFN-γ production, yet low-level TCR activation synergizes with type I IFN to induce IFN-γ production in murine γδ IELs. Further investigation into the underlying molecular mechanisms of costimulation revealed that TCRγδ-mediated activation of NFAT and JNK is required for type I IFN to promote IFN-γ expression in a STAT4-dependent manner. Whereas type I IFN rapidly upregulates antiviral gene expression independent of a basal TCRγδ signal, neither tonic TCR triggering nor the presence of a TCR agonist was sufficient to elicit type I IFN-induced IFN-γ production in vivo. However, bypassing proximal TCR signaling events synergized with IFNAR/STAT4 activation to induce γδ IEL IFN-γ production. These findings indicate that γδ IELs contribute to host defense in response to type I IFN by mounting a rapid antimicrobial response independent of TCRγδ signaling, and may produce IFN-γ in a TCR-dependent manner under permissive conditions.

Metformin, a drug prescribed for patients with type 2 diabetes, has potential efficacy in enhancing antitumor immunity; however, the detailed underlying mechanisms remain to be elucidated. Therefore, we aimed to identify the inhibitory molecular mechanisms of metformin on programmed death ligand 1 (PD-L1) expression in cancer cells and programmed death 1 (PD-1) expression in immune cells.

We employed a luciferase reporter assay, quantitative real-time PCR, immunoblotting analysis, immunoprecipitation and ubiquitylation assays, and a natural killer (NK) cell-mediated tumor cell cytotoxicity assay. A mouse xenograft tumor model was used to evaluate the effect of metformin on tumor growth, followed by flow-cytometric analysis using tumor-derived single-cell suspensions.

Metformin decreased AKT-mediated β-catenin S552 phosphorylation and subsequent β-catenin transactivation in an adenosine monophosphate-activated protein kinase (AMPK) activation-dependent manner, resulting in reduced CD274 (encoding PD-L1) transcription in cancer cells. Tumor-derived soluble factors enhanced PD-1 protein stability in NK and T cells via dissociation of PD-1 from ubiquitin E3 ligases and reducing PD-1 polyubiquitylation. Metformin inhibited the tumor-derived soluble factor-reduced binding of PD-1 to E3 ligases and PD-1 polyubiquitylation, resulting in PD-1 protein downregulation in an AMPK activation-dependent manner. These inhibitory effects of metformin on both PD-L1 and PD-1 expression ameliorated cancer-reduced cytotoxic activity of immune cells in vitro and decreased tumor immune evasion and growth in vivo.

Metformin blocks both PD-L1 and PD-1 within the tumor microenvironment. This study provided a mechanistic insight into the efficacy of metformin in improving immunotherapy in human cancer.

Programmed cell death 1 (PD-1), a key immune checkpoint receptor, has been extensively studied for its role in regulating immune responses in cancer. However, recent research has unveiled a complex and dual role for PD-1 in tumorigenesis. While PD-1 is traditionally associated with immune cells, this article explores its expression in various cancer cells and its impact on cancer progression. PD-1's functions extend beyond immune regulation, as it has been found to both promote and suppress tumor growth, depending on the cancer type. These findings have significant implications for the future of cancer treatment and our understanding of the immune response in the context of cancer. This article calls for further research into the multifaceted roles of PD-1 to optimize its therapeutic potential and improve patient outcomes in the fight against cancer.

To investigate the effect of Ganoderma Lucidum Spore Oil (GLSO) on the tumor growth and survival of H22 tumor-bearing mice treated with cyclophosphamide (CTX), and explore the underlying mechanism.

Allograft H22 hepatocellular carcinoma mouse model was applied to investigate the effect of GLSO on the tumor growth and survival of animals, and Kaplan-Meier survival analysis was used to analyze the life span. Plasma biochemical examination was used to determine the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea (UREA) and creatinine (CRE). Western blot analysis was performed to detect Programmed Death-1 (PD-1), Programmed Death Ligand 1 (PD-L1), Janus Kinase 2 (JAK2), phosphorylated Signal Transducer and Activator of Transcription 3 (p-STAT3), and Signal Transducer and Activator of Transcription 3 (STAT3) expression.

GLSO increased the anti-tumor effect of CTX and prolonged the survival of H22 tumor-bearing mice treated with CTX. Meanwhile, GLSO increased the thymus index and showed no obvious toxicity to liver functions of animals. GLSO also decreased the level of UREA in H22 tumor-bearing mice treated with CTX. Furthermore, GLSO could inhibit the expression of PD-1 in spleen, which was independent of JAK2 expression and STAT3 phosphorylation. However, GLSO did not affect the expression of PD-L1, JAK2, and p-STAT3 in tumor tissue.

GLSO could strengthen the anti-tumor effect of CTX and prolong the life span of H22 tumor-bearing mice, while the underlying mechanism might be relevant to the amelioration effect of thymus function and inhibition of PD-1 expression in spleen. Furthermore, these findings implied the promising role of GLSO in combination with CTX to extend the survival of patients in clinical chemotherapy of hepatocellular carcinoma.

In recent years, with the continuous development of molecular immunology, immune checkpoint inhibitors (ICIs) have also been widely used in the treatment of gastric cancer, but they still face some challenges: The first is that only some people can benefit, the second is the treatment-related adverse events (TRAEs) that occur during treatment, and the third is the emergence of varying degrees of drug resistance with long-term use. How to overcome these challenges, combined therapy based on ICIs has become one of the important strategies. This article summarizes the clinical application of ICIs combined with chemotherapy, targeted therapy, radiotherapy, photodynamic therapy, thermotherapy, immune adjuvant, and dual immunotherapy and discusses the mechanism, and also summarizes the advantages and disadvantages of the current combination modalities and the potential research value. The aim of this study is to provide more and more optimized combination regimen for ICI combined therapy in patients with advanced gastric cancer and to provide reference for clinical and scientific research.

Despite advances in understanding systemic lupus erythematosus (SLE), many challenges remain in unraveling the precise mechanisms behind the disease's development and progression. Recent evidence has questioned the role of programmed cell death protein 1 (PD-1) in suppressing autoreactive CD4+ T cells during autoimmune responses. Research has investigated the potential impacts of PD-1 on various CD4+ T-cell subpopulations, including T follicular helper (Tfh) cells, circulating Tfh (cTfh) cells, and T peripheral helper (Tph) cells, all of which exhibit substantial PD-1 expression and are closely related to several autoimmune disorders, including SLE. This review highlights the complex role of PD-1 in autoimmunity and emphasizes the imperative for further research to elucidate its functions during autoreactive T-cell responses. Additionally, we address the potential of PD-1 and its ligands as possible therapeutic targets in SLE.

PD-1 (Programmed cell death protein 1) regulates the metabolic reprogramming of myeloid-derived suppressor cells and myeloid cell differentiation, as well as the type I interferon (IFN-I) signaling pathway in myeloid cells in the tumor microenvironment. PD-1, therefore, is a key inhibitory receptor in myeloid cells. However, the regulation of PD-1 expression in myeloid cells is unknown. We report that the expression level of PDCD1, the gene that encodes the PD-1 protein, is positively correlated with the levels of IFNB1 and IFNAR1 in myeloid cells in human colorectal cancer. Treatment of mouse myeloid cell lines with recombinant IFNβ protein elevated PD-1 expression in myeloid cells in vitro. Knocking out IFNAR1, the gene that encodes the IFN-I-specific receptor, diminished the inductive effect of IFNβ on PD-1 expression in myeloid cells in vitro. Treatment of tumor-bearing mice with a lipid nanoparticle-encapsulated IFNβ-encoding plasmid (IFNBCOL01) increased IFNβ expression, resulting in elevated PD-1 expression in tumor-infiltrating myeloid cells. At the molecular level, we determined that IFNβ activates STAT1 (signal transducer and activator of transcription 1) and IRFs (interferon regulatory factors) in myeloid cells. Analysis of the cd279 promoter identified IRF2-binding consensus sequence elements. ChIP (chromatin immunoprecipitation) analysis determined that the pSTAT1 directly binds to the irf2 promoter and that IRF2 directly binds to the cd279 promoter in myeloid cells in vitro and in vivo. In colon cancer patients, the expression levels of STAT1, IRF2 and PDCD1 are positively correlated in tumor-infiltrating myeloid cells. Our findings determine that IFNβ activates PD-1 expression at least in part by an autocrine mechanism via the stimulation of the pSTAT1-IRF2 axis in myeloid cells.

Androgen has long been recognized for its pivotal role in the sexual dimorphism of cardiovascular diseases, including aortic aneurysms (AAs), a devastating vascular disease with a higher prevalence and fatality rate in men than in women. However, the mechanism by which androgen mediates AAs is largely unknown. Here, we found that male, not female, mice developed AAs when exposed to aldosterone and high salt (Aldo-salt). We revealed that androgen and androgen receptors (ARs) were crucial for this sexually dimorphic response to Aldo-salt. We identified programmed cell death protein 1 (PD-1), an immune checkpoint, as a key link between androgen and AAs. Furthermore, we demonstrated that administration of anti-PD-1 Ab and adoptive PD-1-deficient T cell transfer reinstated Aldo-salt-induced AAs in orchiectomized mice and that genetic deletion of PD-1 exacerbated AAs induced by a high-fat diet and angiotensin II (Ang II) in nonorchiectomized mice. Mechanistically, we discovered that the AR bound to the PD-1 promoter to suppress the expression of PD-1 in the spleen. Thus, our study unveils a mechanism by which androgen aggravates AAs by suppressing PD-1 expression in T cells. Moreover, our study suggests that some patients with cancer might benefit from screenings for AAs during immune checkpoint therapy.

Harnessing the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) axis is pivotal in autoimmunity and cancer immunotherapy. PD-1 receptors on immune cells engage with one of its ligands, PD-L1 or PD-L2, expressed on antigen-presenting cells or tumor cells, driving T-cell dysfunction and tumor immune escape. Thus, targeting PD-1/PD-L1 revitalizes cytotoxic T cells for cancer elimination. However, a majority of cancer patients don't respond to PD-1/PD-L1 blockade, and the underlying mechanisms remain partially understood. Recent studies have revealed that PD-1 expression levels or modifications impact the effectiveness of anti-PD-1/PD-L1 treatments. Therefore, understanding the molecular mechanisms governing PD-1 expression and modifications is crucial for innovating therapeutic strategies to enhance the efficacy of PD-1/PD-L1 inhibition. This article presents a comprehensive overview of advancements in PD-1 regulation and highlights their potential in modulating immune homeostasis and cancer immunotherapy, aiming to refine clinical outcomes.

Background and Aims: Liver inflammation is important in guiding the initiation of antiviral treatment and affects the progression of chronic hepatitis B(CHB). The soluble programmed cell death 1 protein (sPD-1) was upregulated in inflammatory and infectious diseases and correlated with disease severity. We aimed to investigate the correlation between serum sPD-1 levels and liver inflammation in CHB patients and their role in indicating liver inflammation. Methods: 241 CHB patients who underwent liver biopsy were enrolled. The correlation between sPD-1 levels and the degree of liver inflammation was analyzed. Univariate and multivariate logistic regression analyses were performed to analyze independent variables of severe liver inflammation. Binary logistic regression analysis was conducted to construct a predictive model for severe liver inflammation, and the receiver operating characteristic curve (ROC) was used to evaluate the diagnostic accuracy of the predictive model. Results: sPD-1 was highest in CHB patients with severe liver inflammation, which was higher than that in CHB patients with mild or moderate liver inflammation (P < 0.001). Besides, sPD-1 was weakly correlated with AST (r = 0.278, P < 0.001). Multivariable analysis showed that sPD-1 was an independent predictor of severe liver inflammation. The predictive model containing sPD-1 had areas under the ROC (AUROCs) of 0.917 and 0.921 in predicting severe liver inflammation in CHB patients and CHB patients with ALT ≤ 1× upper limit of normal (ULN), respectively. Conclusions: Serum sPD-1 level is associated with liver inflammation in CHB patients, and high levels of sPD-1 reflect severe liver inflammation. Serum sPD-1 is an independent predictor of severe liver inflammation and shows improved diagnostic accuracy when combined with other clinical indicators.

Programmed cell death protein 1 (PD-1) binds to its ligand to help tumours evade the immune system and promote tumour progression. Although anti-PD-1/PD-L1 therapies show powerful effects in some patients, most patients are unable to benefit from this treatment due to treatment resistance. Therefore, it is important to overcome tumour resistance to PD-1/PD-L1 blockade. There is substantial evidence suggesting that the JAK/STAT signalling pathway plays a significant role in PD-1/PD-L1 expression and anti-PD-1/PD-L1 treatment. Herein, we describe the effects of the JAK/STAT signalling pathway on PD-1/PD-L1. Subsequently, the relationship between molecular mutations in the JAK/STAT signalling pathway and immune resistance was analysed. Finally, the latest advancements in drugs targeting the JAK/STAT pathway combined with PD1/PD-L1 inhibitors are summarised.

Intraepithelial lymphocytes (IEL) expressing the γδ T cell receptor (TCR) survey the intestinal epithelium to limit the invasion of microbial pathogens. The production of type I interferon (IFN) is a central component of an antiviral immune response, yet how these pro-inflammatory cytokines contribute to γδ IEL effector function remains unclear. Based on the unique activation status of IELs, and their ability to bridge innate and adaptive immunity, we investigated the extent to which type I IFN signaling modulates γδ IEL function. Using an ex vivo culture model, we find that type I IFN alone is unable to drive IFNγ production, yet low level TCR activation synergizes with type I IFN to induce IFNγ production in murine γδ IELs. Further investigation into the underlying molecular mechanisms of co-stimulation revealed that TCRγδ-mediated activation of NFAT and JNK is required for type I IFN to promote IFNγ expression in a STAT4- dependent manner. Whereas type I IFN rapidly upregulates antiviral gene expression independent of a basal TCRγδ signal, neither tonic TCR triggering nor the presence of a TCR agonist was sufficient to elicit type I IFN-induced IFNγ production in vivo . However, bypassing proximal TCR signaling events synergized with IFNAR/STAT4 activation to induce γδ IEL IFNγ production. These findings indicate that γδ IELs contribute to host defense in response to type I IFN by mounting a rapid antimicrobial response independent of TCRγδ signaling, and under permissive conditions, produce IFNγ in a TCR-dependent manner.

Programmed cell death protein 1 (PD-1), a coinhibitory T cell checkpoint, is also expressed on macrophages in pathogen- or tumor-driven chronic inflammation. Increasing evidence underscores the importance of PD-1 on macrophages for dampening immune responses. However, the mechanism governing PD-1 expression in macrophages in chronic inflammation remains largely unknown. TGF-β1 is abundant within chronic inflammatory microenvironments. Here, based on public databases, significantly positive correlations between PDCD1 and TGFB1 gene expression were observed in most human tumors. Of note, among immune infiltrates, macrophages as the predominant infiltrate expressed higher PDCD1 and TGFBR1/TGFBR2 genes. MC38 colon cancer and Schistosoma japonicum infection were used as experimental models for chronic inflammation. PD-1hi macrophages from chronic inflammatory tissues displayed an immunoregulatory pattern and expressed a higher level of TGF-β receptors. Either TGF-β1-neutralizing antibody administration or macrophage-specific Tgfbr1 knockdown largely reduced PD-1 expression on macrophages in animal models. We further demonstrated that TGF-β1 directly induced PD-1 expression on macrophages. Mechanistically, TGF-β1-induced PD-1 expression on macrophages was dependent on SMAD3 and STAT3, which formed a complex at the Pdcd1 promoter. Collectively, our study shows that macrophages adapt to chronic inflammation through TGF-β1-triggered cooperative SMAD3/STAT3 signaling that induces PD-1 expression and modulates macrophage function.

Despite the success of immuno-oncology in clinical settings, the therapeutic efficacy is lower than the expectation due to the immunosuppressive inflammatory tumor microenvironment (TME) and the lack of functional lymphocytes caused by exhaustion. To enhance the efficacy of immuno-oncotherapy, a synergistic strategy should be used that can effectively improve the inflammatory TME and increase the tumor infiltration of cytotoxic T lymphocytes (CTLs). Herein, a TME hypoxia-responsive nanogel (NG) is developed to enhance the delivery and penetration of diacerein and (-)-epigallocatechin gallate (EGCG) in tumors. After systemic administration, diacerein effectively improves the tumor immunosuppressive condition through a reduction of MDSCs and Tregs in TME, and induces tumor cell apoptosis via the inhibition of IL-6/STAT3 signal pathway, realizing a strong antitumor effect. Additionally, EGCG can effectively inhibit the expression of PD-L1, restoring the tumor-killing function of CTLs. The infiltration of CTLs increases at the tumor site with activation of systemic immunity after the combination of TIM3 blockade therapy, ultimately resulting in a strong antitumor immune response. This study provides valuable insights for future research on eliciting effective antitumor immunity by suppressing adverse tumor inflammation. The feasible strategy proposed in this work may solve the urgent clinical concerns of the dissatisfactory checkpoint-based immuno-oncotherapy.

Antibodies can block immune receptor engagement or trigger the receptor machinery to initiate signaling. We hypothesized that antibody agonists trigger signaling by sterically excluding large receptor-type protein tyrosine phosphatases (RPTPs) such as CD45 from sites of receptor engagement. An agonist targeting the costimulatory receptor CD28 produced signals that depended on antibody immobilization and were sensitive to the sizes of the receptor, the RPTPs, and the antibody itself. Although both the agonist and a non-agonistic anti-CD28 antibody locally excluded CD45, the agonistic antibody was more effective. An anti-PD-1 antibody that bound membrane proximally excluded CD45, triggered Src homology 2 domain-containing phosphatase 2 recruitment, and suppressed systemic lupus erythematosus and delayed-type hypersensitivity in experimental models. Paradoxically, nivolumab and pembrolizumab, anti-PD-1-blocking antibodies used clinically, also excluded CD45 and were agonistic in certain settings. Reducing these agonistic effects using antibody engineering improved PD-1 blockade. These findings establish a framework for developing new and improved therapies for autoimmunity and cancer.

Intratumoral immune status influences tumor therapeutic response, but it remains largely unclear how the status determines therapies for patients with intrahepatic cholangiocarcinoma. Here, we examine the single-cell transcriptional and TCR profiles of 18 tumor tissues pre- and post- therapy of gemcitabine plus oxaliplatin, in combination with lenvatinib and anti-PD1 antibody for intrahepatic cholangiocarcinoma. We find that high CD8 GZMB+ and CD8 proliferating proportions and a low Macro CD5L+ proportion predict good response to the therapy. In patients with a poor response, the CD8 GZMB+ and CD8 proliferating proportions are increased, but the CD8 GZMK+ proportion is decreased after the therapy. Transition of CD8 proliferating and CD8 GZMB+ to CD8 GZMK+ facilitates good response to the therapy, while Macro CD5L+-CD8 GZMB+ crosstalk impairs the response by increasing CTLA4 in CD8 GZMB+. Anti-CTLA4 antibody reverses resistance of the therapy in intrahepatic cholangiocarcinoma. Our data provide a resource for predicting response of the combination therapy and highlight the importance of CD8+T-cell status conversion and exhaustion induced by Macro CD5L+ in influencing the response, suggesting future avenues for cancer treatment optimization.

Persisting alloreactive donor T cells in target tissues are a determinant of graft-versus-host disease (GVHD), but the transcriptional regulators that control the persistence and function of tissue-infiltrating T cells remain elusive. We demonstrate here that Id3, a DNA-binding inhibitor, is critical for sustaining T-cell responses in GVHD target tissues in mice, including the liver and intestine. Id3 loss results in aberrantly expressed PD-1 in polyfunctional T helper 1 (Th1) cells, decreased tissue-infiltrating PD-1+ polyfunctional Th1 cell numbers, impaired maintenance of liver TCF-1+ progenitor-like T cells, and inhibition of GVHD. PD-1 blockade restores the capacity of Id3-ablated donor T cells to mediate GVHD. Single-cell RNA-sequencing analysis revealed that Id3 loss leads to significantly decreased CD28- and PI3K/AKT-signaling activity in tissue-infiltrating polyfunctional Th1 cells, an indicator of active PD-1/PD-L1 effects. Id3 is also required for protecting CD8+ T cells from the PD-1 pathway-mediated suppression during GVHD. Genome-wide RNA-sequencing analysis reveals that Id3 represses transcription factors (e.g., Nfatc2, Fos, Jun, Ets1, and Prdm1) that are critical for PD-1 transcription, exuberant effector differentiation, and interferon responses and dysfunction of activated T cells. Id3 achieves these effects by restraining the chromatin accessibility for these transcription factors. Id3 ablation in donor T cells preserved their graft vs tumor effects in mice undergoing allogeneic hematopoietic stem cell transplantation. Furthermore, CRISPR/Cas9 knockout of ID3 in human CD19-directed chimeric antigen receptor T cells retained their antitumor activity in NOD/SCID/IL2Rg-/- mice early after administration. These findings identify that ID3 is an important target to reduce GVHD, and the gene-editing program of ID3 may have broad implications in T-cell-based immunotherapy.

Chimeric antigen receptor (CAR) T-cells have revolutionized the treatment of CD19- and B-cell maturation antigen-positive haematological malignancies. However, the effect of a CAR construct on the function of T-cells stimulated via their endogenous T-cell receptors (TCRs) has yet to be comprehensively investigated.

Experiments were performed to systematically assess TCR signalling and function in CAR T-cells using anti-mesothelin human CAR T-cells as a model system. CAR T-cells expressing the CD28 or 4-1BB costimulatory endodomains were manufactured and compared to both untransduced T-cells and CAR T-cells with a non-functional endodomain. These cell products were treated with staphylococcal enterotoxin B to stimulate the TCR, and in vitro functional assays were performed by flow cytometry.

Increased proliferation, CD69 expression and IFNγ production were identified in CD8+ 4-1BBζ CAR T-cells compared to control untransduced CD8+ T-cells. These functional differences were associated with higher levels of phosphorylated ZAP70 after stimulation. In addition, these functional differences were associated with a differing immunophenotype, with a more than two-fold increase in central memory cells in CD8+ 4-1BBζ CAR T-cell products.

Our data indicate that the 4-1BBζ CAR enhances CD8+ TCR-mediated function. This could be beneficial if the TCR targets epitopes on malignant tissues or infectious agents, but detrimental if the TCR targets autoantigens.

Fighting cancer remains one of the greatest challenges for science in the 21st century. Advances in immunotherapy against different types of cancer have greatly contributed to the treatment, remission, and cure of patients. In this context, knowledge of epigenetic phenomena, their relationship with tumor cells and how the immune system can be epigenetically modulated represent some of the greatest advances in the development of anticancer therapies. Epigenetics is a rapidly growing field that studies how environmental factors can affect gene expression without altering DNA sequence. Epigenomic changes include DNA methylation, histone modifications, and non-coding RNA regulation, which impact cellular function. Epigenetics has shown promise in developing cancer therapies, such as immunotherapy, which aims to stimulate the immune system to attack cancer cells. For example, PD-1 and PD-L1 are biomarkers that regulate the immune response to cancer cells and recent studies have shown that epigenetic modifications can affect their expression, potentially influencing the efficacy of immunotherapy. New therapies targeting epigenetic modifications, such as histone deacetylases and DNA methyltransferases, are being developed for cancer treatment, and some have shown promise in preclinical studies and clinical trials. With growing understanding of epigenetic regulation, we can expect more personalized and effective cancer immunotherapies in the future. This review highlights key advances in the use of epigenetic and epigenomic tools and modern immuno-oncology strategies to treat several types of tumors.

Allogeneic hematopoietic stem cell transplantation (alloSCT) is, in many clinical settings, the only curative treatment for acute myeloid leukemia (AML). The clinical benefit of alloSCT greatly relies on the graft-versus-leukemia (GVL) effect. However, AML relapse remains the top cause of posttransplant death; this highlights the urgent need to enhance GVL. Studies of human GVL have been hindered by the lack of optimal clinically relevant models. In this article, we report, the successful establishment of a novel (to our knowledge) humanized GVL model system by transplanting clinically paired donor PBMCs and patient AML into MHC class I/II knockout NSG mice. We observed significantly reduced leukemia growth in humanized mice compared with mice that received AML alone, demonstrating a functional GVL effect. Using this model system, we studied human GVL responses against human AML cells in vivo and discovered that AML induced T cell depletion, likely because of increased T cell apoptosis. In addition, AML caused T cell exhaustion manifested by upregulation of inhibitory receptors, increased expression of exhaustion-related transcription factors, and decreased T cell function. Importantly, combined blockade of human T cell-inhibitory pathways effectively reduced leukemia burden and reinvigorated CD8 T cell function in this model system. These data, generated in a highly clinically relevant humanized GVL model, not only demonstrate AML-induced inhibition of alloreactive T cells but also identify promising therapeutic strategies targeting T cell depletion and exhaustion for overcoming GVL failure and treating AML relapse after alloSCT.

Immune effector cells in the microenvironment tend to be depleted or remodeled, unable to perform normal functions, and even promote the malignant characterization of tumors, resulting in the formation of immunosuppressive microenvironments. The strategy of reversing immunosuppressive microenvironment has been widely used to enhance the tumor immunotherapy effect. Signal transducer and activator of transcription 3 (STAT3) was found to be a crucial regulator of immunosuppressive microenvironment formation and activation as well as a factor, stimulating tumor cell proliferation, survival, invasiveness and metastasis. Therefore, regulating the immune microenvironment by targeting the STAT3 oncogenic pathway might be a new cancer therapy strategy. This review discusses the pleiotropic effects of STAT3 on immune cell populations that are critical for tumorigenesis, and introduces the novel strategies targeting STAT3 oncogenic pathway for cancer immunotherapy. Lastly, we summarize the conventional drugs used in new STAT3-targeting anti-tumor applications.

PD1 was originally discovered in 1992 as a molecule associated with activation-induced cell death in T cells. Over the past 30 years, it was found that PD1 has a critical role in avoiding overactivation-induced cell death and autoimmunity, whereas its inhibition unleashes anticancer immunity. Here, we outline the journey from the discovery of PD1 to its role as a breakthrough target in cancer immunotherapy. We describe its regulation and function and examine how a mechanistic understanding of PD1 signalling suggests a central function in setting the T cell activation threshold, thereby controlling T cell proliferation, differentiation, exhaustion and metabolic status. This threshold theory, in combination with new insights into T cell metabolism and a better understanding of immune cell modulation by the microbiota, can provide guidance for the development of efficient combination therapies. Moreover, we discuss the mechanisms underlying immune-related adverse events after PD1-targeted therapy and their possible treatment.

Clear cell renal cell carcinoma (ccRCC) has a high degree of malignancy and poor overall prognosis in advanced and metastatic patients. Therefore, it is of great significance to find new prognostic biomarkers and therapeutic targets for ccRCC. The expression of progestin and adipoQ receptor family member 5 (PAQR5) is significantly downregulated in ccRCC compared with normal tissues, but its specific mechanism and potential biological function in ccRCC remain unclear.

The expression pattern of PAQR5 and the correlation between the PAQR5 expression and clinicopathological parameters and various survival periods in ccRCC patients were analyzed by using multiple public databases and ccRCC tissues chip. Its prognostic value was analyzed by univariate/multivariate Cox regression. In addition, MTT assay, EdU staining assay, flow cytometry, wound healing assay, transwell migration and invasion assay, colony formation assay, immunofluorescence assay, and a xenograft tumor model were conducted to assess the biological function of PAQR5 in ccRCC in vitro and in vivo.

Our results indicated that the downregulation of PAQR5 was demonstrated in ccRCC tumor tissues and associated with poorer OS, DSS, and PFI. Meanwhile, the univariate/multivariate Cox regression analysis confirmed that PAQR5 might serve as an independent prognostic factor for ccRCC, and its low expression was tightly correlated with tumor progression and distant metastasis. Mechanistically, a series of gain- and loss-of-function assay revealed that PAQR5 could suppress the ccRCC proliferation, invasion, metastasis, and tumorigenicity in vitro and in vivo by inhibiting the JAK/STAT3 signaling pathway.

Our study revealed the tumor suppressor role of PAQR5 in ccRCC. PAQR5 is a valuable prognostic biomarker for ccRCC and may provide new strategies for clinical targeted therapy.

Immune-checkpoint inhibitors (ICBs), in addition to targeting CTLA-4, PD-1, and PD-L1, novel targeting LAG-3 drugs have also been approved in clinical application. With the widespread use of the drug, we must deeply analyze the dilemma of the agents and seek a breakthrough in the treatment prospect. Over the past decades, these agents have demonstrated dramatic efficacy, especially in patients with melanoma and non-small cell lung cancer (NSCLC). Nonetheless, in the field of a broad concept of solid tumours, non-specific indications, inseparable immune response and side effects, unconfirmed progressive disease, and complex regulatory networks of immune resistance are four barriers that limit its widespread application. Fortunately, the successful clinical trials of novel ICB agents and combination therapies, the advent of the era of oncolytic virus gene editing, and the breakthrough of the technical barriers of mRNA vaccines and nano-delivery systems have made remarkable breakthroughs currently. In this review, we enumerate the mechanisms of each immune checkpoint targets, associations between ICB with tumour mutation burden, key immune regulatory or resistance signalling pathways, the specific clinical evidence of the efficacy of classical targets and new targets among different tumour types and put forward dialectical thoughts on drug safety. Finally, we discuss the importance of accurate triage of ICB based on recent advances in predictive biomarkers and diagnostic testing techniques.

Immune cells such as T cells and macrophages express α7 nicotinic acetylcholine receptors (α7 nAChRs), which contribute to the regulation of immune and inflammatory responses. Earlier findings suggest α7 nAChR activation promotes the development of regulatory T cells (Tregs) in mice. Using human CD4+ T cells, we investigated the mRNA expression of the α7 subunit and the human-specific dupα7 nAChR subunit, which functions as a dominant-negative regulator of ion channel function, under resting conditions and T cell receptor (TCR)-activation. We then explored the effects of the selective α7 nAChR agonist GTS-21 on proliferation of TCR-activated T cells and Treg development. Varied levels of mRNA for both the α7 and dupα7 nAChR subunits were detected in resting human CD4+ T cells. mRNA expression of the α7 nAChR subunit was profoundly suppressed on days 4 and 7 of TCR-activation as compared to day 1, whereas mRNA expression of the dupα7 nAChR subunit remained nearly constant. GTS-21 did not alter CD4+ T cell proliferation but significantly promoted Treg development. These results suggest the potential ex vivo utility of GTS-21 for preparing Tregs for adoptive immunotherapy, even with high expression of the dupα7 subunit.

Tumor-specific CD8+ T cells are critical components of antitumor immunity; however, factors that modulate their phenotype and function have not been completely elucidated. Cytokines IL-12 and IL-27 have recognized roles in promoting CD8+ T cells' effector function and mediated antitumor responses. Tumor-specific CD8+ tumor-infiltrating lymphocytes (TILs) can be identified based on surface expression of CD39, whereas bystander CD8+ TILs do not express this enzyme. It is currently unclear how and why tumor-specific CD8+ T cells uniquely express CD39. Given the important roles of IL-12 and IL-27 in promoting CD8+ T cell functionality, we investigated whether these cytokines could modulate CD39 expression on these cells. Using in vitro stimulation assays, we identified that murine splenic CD8+ T cells differentially upregulate CD39 in the presence of IL-12 and IL-27. Subsequently, we assessed the exhaustion profile of IL-12- and IL-27-induced CD39+CD8+ T cells. Despite the greatest frequency of exhausted CD39+CD8+ T cells after activation with IL-12, as demonstrated by the coexpression of TIM-3+PD-1+LAG-3+ and reduced degranulation capacity, these cells retained the ability to produce IFN-γ. IL-27-induced CD39+CD8+ T cells expressed PD-1 but did not exhibit a terminally exhausted phenotype. IL-27 was able to attenuate IL-12-mediated inhibitory receptor expression on CD39+CD8+ T cells but did not rescue degranulation ability. Using an immunogenic neuro-2a mouse model, inhibiting IL-12 activity reduced CD39+CD8+ TIL frequency compared with controls without changing the overall CD8+ TIL frequency. These results provide insight into immune regulators of CD39 expression on CD8+ T cells and further highlight the differential impact of CD39-inducing factors on the phenotype and effector functions of CD8+ T cells.

Programmed cell death protein 1 (PD-1), expressed on tumor-infiltrating T cells, is a T cell exhaustion marker. The mechanisms underlying PD-1 upregulation in CD4 T cells remain unknown. Here we develop nutrient-deprived media and a conditional knockout female mouse model to study the mechanism underlying PD-1 upregulation. Reduced methionine increases PD-1 expression on CD4 T cells. The genetic ablation of SLC43A2 in cancer cells restores methionine metabolism in CD4 T cells, increasing the intracellular levels of S-adenosylmethionine and yielding H3K79me2. Reduced H3K79me2 due to methionine deprivation downregulates AMPK, upregulates PD-1 expression and impairs antitumor immunity in CD4 T cells. Methionine supplementation restores H3K79 methylation and AMPK expression, lowering PD-1 levels. AMPK-deficient CD4 T cells exhibit increased endoplasmic reticulum stress and Xbp1s transcript levels. Our results demonstrate that AMPK is a methionine-dependent regulator of the epigenetic control of PD-1 expression in CD4 T cells, a metabolic checkpoint for CD4 T cell exhaustion.

Cerebral ischemic stroke and glioma are the two leading causes of patient mortality globally. Despite physiological variations, 1 in 10 people who have an ischemic stroke go on to develop brain cancer, most notably gliomas. In addition, glioma treatments have also been shown to increase the risk of ischemic strokes. Stroke occurs more frequently in cancer patients than in the general population, according to traditional literature. Unbelievably, these events share multiple pathways, but the precise mechanism underlying their co-occurrence remains unknown. Transcription factors (TFs), the main components of gene expression programmes, finally determine the fate of cells and homeostasis. Both ischemic stroke and glioma exhibit aberrant expression of a large number of TFs, which are strongly linked to the pathophysiology and progression of both diseases. The precise genomic binding locations of TFs and how TF binding ultimately relates to transcriptional regulation remain elusive despite a strong interest in understanding how TFs regulate gene expression in both stroke and glioma. As a result, the importance of continuing efforts to understand TF-mediated gene regulation is highlighted in this review, along with some of the primary shared events in stroke and glioma.

Immune checkpoint inhibitors (ICI) have significantly improved treatment outcomes for several types of cancer over the past decade, but significant challenges that limit wider effectiveness of current immunotherapies remain to be addressed. Certain "cold" tumor types, such as pancreatic cancer, exhibit very low response rates to ICI due to intrinsically low immunogenicity. In addition, many patients who initially respond to ICI lack a sustained response due to T-cell exhaustion. Several recent studies show that epigenetic modifiers, such as SETDB1 and LSD1, can play critical roles in regulating both tumor cell-intrinsic immunity and T-cell exhaustion. Here, we review the evidence showing that multiple epigenetic regulators silence the expression of endogenous antigens, and their loss induces viral mimicry responses bolstering the response of "cold" tumors to ICI in preclinical models. Similarly, a previously unappreciated role for epigenetic enzymes is emerging in the establishment and maintenance of stem-like T-cell populations that are critical mediators of response to ICI. Targeting the crossroads of epigenetics and immune checkpoint therapy has tremendous potential to improve antitumor immune responses and herald the next generation of sustained responses in immuno-oncology.

The incidence rate and mortality of gastric cancer remain elevated. Traditionally, surgical treatment (including endoscopic surgery and traditional surgery), chemotherapy, targeted therapy, and immunotherapy were used for the treatment of gastric cancer. Although the emergence of targeted therapy and immunotherapy can effectively prolong the survival of some patients with gastric cancer and improve the quality of life of patients after chemotherapy or surgery, the overall survival rate of gastric cancer has not been significantly improved. Photodynamic therapy is a local photochemical therapy with the advantages of high safety, few adverse reactions, and repeatability, although it may cause some toxic reactions. There are some differences between East and West in the treatment of gastric cancer with PDT, and most earlier studies concentrated on using PDT alone. However, some studies have indicated that PDT may enhance the efficacy of chemotherapy and other medications. This paper summarizes the study on the use of PDT and its combination therapy in gastric cancer, which is anticipated to offer novel thoughts for the treatment of gastric cancer.