Programmed Death Ligand-1 Signaling Pathway Research Articles

Dual impacts of serine/glycine-free diet in enhancing antitumor immunity and promoting evasion via PD-L1 lactylation

The effect of the serine/glycine-free diet (-SG diet) on colorectal cancer (CRC) remains unclear; meanwhile, programmed death-1 (PD-1) inhibitors are less effective for most CRC patients. Here, we demonstrate that the -SG diet inhibits CRC growth and promotes the accumulation of cytotoxic Tcells to enhance antitumor immunity. Additionally, we also identified the lactylation of programmed death-ligand 1 (PD-L1) in tumor cells as a mechanism of immune evasion during cytotoxic Tcell-mediated antitumor responses, and blocking the PD-1/PD-L1 signaling pathway is able to rejuvenate the function of CD8+ Tcells recruited by the -SG diet, indicating the potential of combining the -SG diet with immunotherapy. We conducted a single-arm, phase I study (ChiCTR2300067929). The primary outcome suggests that the -SG diet is feasible and safe for regulating systemic immunity. Secondary outcomes include patient tolerability and potential antitumor effects. Collectively, our findings highlight the promising therapeutic potential of the -SG diet for treating solid tumors.

Regulation of cervical cancer via G15-mediated inhibition of G protein-coupled estrogen receptor.

Cervical cancer is among the most common gynecological malignancies. G protein-coupled estrogen receptor (GPER) is involved in the development of various tumors; however, its role in cervical cancer remains unclear. We investigated whether G15, an inhibitor of GPER, can regulate its expression and affect cervical cancer progression. We examined the biological behaviors of G15-treated SiHa and HeLa cells using Cell Counting Kit-8, monoclonal proliferation, plate scratching, and Transwell invasion experiments. Western blotting was used to detect the expression of GPER, E-cadherin, N-cadherin, vimentin, Bcl-2, Bax, phosphatidylinositol-3-kinase (PI3K)/AKT, and programmed death ligand 1 (PD-L1). The expression of GPER, E-cadherin, vimentin, and PD-L1 in cervical cancer and adjacent tissues was detected using immunohistochemistry. The correlation between GPER expression and clinicopathological characteristics was analyzed. The expression of GPER in cervical cancer tissues was significantly higher than that in paracancerous tissues, and it was detected in the membrane and cytoplasm of SiHa and HeLa cells. The proliferation, migration, and invasion abilities of SiHa and HeLa cells were reduced after G15 treatment. The G15-treated groups exhibited higher expression of E-cadherin and Bax and lower expression of N-cadherin, vimentin, Bcl-2, GPER, p-PI3K, p-AKT, and PD-L1 than the control group. The expression of E-cadherin was lower and that of vimentin was higher in cancer tissues than in paracancerous tissues; PD-L1 was highly expressed in tumor and stromal cells in cancer tissues but not in paracancerous tissues. G15 functions by regulating the GPER/PI3K/AKT/PD-L1 signaling pathway and may serve as a new immunotherapy for treating patients with cervical cancer.

PD-1/PD-L1 Interaction Upregulates YAP1 Expression in HepG2 Cells Through MAPK/ERK Pathway

Background Antibodies, which target programmed cell death protein-1 (PD-1) or its ligand programmed death ligand-1 (PD-L1), can rescue T cells from an exhausted state and resume their immune response to cancer cells. Clinically, the purpose of blocking the PD-1/PD-L1 signaling pathway is to induce immune cells to play an anti-tumor role. However, the effect of intertumor PD-1/PD-L1 signal blocking on tumor cells remains unclear. Methods HepG2 cells were treated with DHA, IFN-γ, BSA, DDP, PD-1-Fc (1 μg/ml), IgG-Fc, nivolumab, or human IgG for 24 h, respectively. GEPIA, cBioPortal, and TIMER databases were used to analyze the correlation between YAP1, PD-1, and PD-L1 and ERK, ERK-5, JNK, and p38. Western blot was used to detect the expression of YAP1 and p-ERK. Results GEPIA, cBioPortal, and TIMER databases analysis showed that YAP1 was positively correlated with ERK. After HepG2 cells were treated with PD98059 (ERK inhibitor), the expression of YAP1 was decreased. In this study, we investigated the inhibitory effect of PD98059 on PD-1/PD-L1 signaling. Our study found that PD-1-Fc (PD-1 fusion protein) promoted the expression of p-ERK/ERK and YAP1 in HepG2 cells. In contrast, nivolumab (PD-1 blocking antibody) reduced the expression of p-ERK/ERK and YAP1 in IFN-γ-pretreated HepG2 cells. In addition, the application of DHA also inhibited the expression of p-ERK/ERK to inhibit YAP1. Furthermore, treatment of HepG2 cells with DHA alone or DHA combined with cisplatin (DDP) both inhibited the expression of p-ERK/ERK and YAP1. Conclusions These results suggested that PD-1/PD-L1 interactions between tumor cells could promote the expression of ERK or YAP1 within tumors. Moreover, the conduction of PD-1/PD-L1 could be reversed using ERK inhibitors.

Effect of MiR-424-5p on the Drug Resistance of Diffuse Large B-Cell Lymphoma Cells by Regulating PD-1/PD-L1 Signaling Pathway

To explore the effect of microRNA-424-5p (miR-424-5p) on the drug resistance of diffuse large B-cell lymphoma (DLBCL) cells by regulating the programmed death receptor-1 (PD-1)/programmed death ligand-1 (PD-L1) signaling pathway. Human DLBCL cell line CRL2631 cells were induced to construct CRL2631-CHOP resistant cell line. RT-qPCR and Western blot were used to detect the expression levels of MiR-424-5p, PD-L1 mRNA and protein, and multidrug resistance gene-1 (MDR-1) protein in CRL2631 cells and CRL2631-CHOP cells, respectively. The target genes of MiR-424-5p was verified by dual luciferase reporter assay. The miRNA simulation/interference technology and thiazole blue (MTT) method were used to detect the resistance of CRL2631 cells and CRL2631-CHOP cells to CHOP. Compared with CRL2631 cells, the drug resistance of CRL2631-CHOP cells to CHOP and the levels of MDR-1 protein (P<0.05), PD-L1 mRNA and protein in the cells were significantly increased (both P<0.001), while the relative level of MiR-424-5p was significantly reduced (P<0.001). The result of the dual luciferase reporter assay showed that PD-L1 was the direct downstream target gene of MiR-424-5p (P<0.001). After transfection of MiR-424-5p inhibitor, the resistance of CRL2631 cells to CHOP drugs increased, and the expression level of MDR-1 protein (P<0.01), PD-L1 mRNA and protein also increased significantly (both P<0.01). After transfection of MiR-424-5p mimics, the resistance of CRL2631-CHOP cells to CHOP drugs decreased, and the expression level of MDR-1 protein (P<0.001), PD-L1 mRNA and protein also decreased significantly (both P<0.001). Overexpression of PD-L1 could reverse the inhibitory effect of upregulating MiR-424-5p on PD-L1 (P<0.001). Down-regulation of MiR-424-5p enhances the drug resistance of DLBCL cells by regulating the PD-1/PD-L1 signaling pathway.

Nanobubbles containing PD-L1 Ab and miR-424 mediated PD-L1 blockade, and its expression inhibition to enable and potentiate hepatocellular carcinoma immunotherapy in mice

Immune checkpoint inhibitors (ICI) therapy is the main type of immunotherapy for cancer. Current clinical trials are focused on enhancing anti-tumor effects through combinations of multiple ICIs with agents that cause tumor cell death and release tumor antigens. In this study, weprepared nanobubbles (NBs) to load programmed death-ligand 1 (PD-L1) antibody andmiR-424gene to evaluate the combined anti-tumor activity of the targeted NBs.The miR-424 gene was chosen to be an anti-tumor gene, which can target PD-L1 and Bcl-2, through bioinformatics analysis and target gene verification. Then, PD-L1 Ab/miR-424-NBs were prepared by thin-film hydration. The optimal shape, size, and character of the NBs were determined by scanning electron microscopy and Zeta potential study. In addition, the antibody binding rate and gene loading of the targeted NBs were studied by agarose gel electrophoresis and flow cytometry, respectively. The synergistic immunotherapeutic effect of anti-PD-L1 antibody andmiR-424in vivo and their mechanism were evaluated using an H22 hepatoma transplanted tumor model in mice,whichproved that the targeted NBs mediated the PD-L1 antibody toblock the PD-1/PD-L1 signaling pathway and the transfected miR-424gene to downregulate the PD-L1 expression of tumor cells, both of which enhanced the antitumor immune effect mediated by T cells. It was also found that the targeted NBs activated T cells, which released a large number of cytokines, such as IFN-γ and IL-2, to recruit and activate macrophages and NK cells. It is suggested that ultrasound-mediated PD-L1 antibody NBs delivering miR-424 can inhibit the growth of subcutaneously transplanted hepatocellular carcinoma in terms of apoptosis and immunity. Therefore, ultrasound-mediated targeted NBs are a potential effective carrier for liver cancer, and PD-L1 antibody and miR-424 have a synergistic anti-tumor immunotherapy effect.

Platycodon grandiflorum Triggers Antitumor Immunity by Restricting PD-1 Expression of CD8+ T Cells in Local Tumor Microenvironment.

In the tumor microenvironment (TME), the activation of programmed death-1 (PD-1)–programmed death ligand-1 (PD-L1) pathway is one of the main signals of immune escape and tumor deterioration. Clinically, the application of monoclonal antibodies slows down the progression of various malignancies and prolongs the survival of patients effectively. However, these treatments result in serious immune-related adverse events (irAEs) owning to systemic immune activation. Therefore, to achieve long-term therapeutic effects and low side effects, it is necessary to find drugs inhibiting the local PD-1/PD-L1 signaling pathway of the TME. Here, we discovered that Platycodon grandiflorum (PG), a medicine and food homology herb, reduced the expression of PD-1 on the surface of CD8+ T cells to exert antitumor effects in non-small cell lung cancer (NSCLC). Firstly, by combining systems pharmacology strategies and clinical data analysis, we found that PG has the potential to immunomodulate T cells and suppress tumors. Secondly, in vivo and in vitro experiments have confirmed the antitumor effect of the combination of Platycodin D and Platycodin D3, which is preferred and representative of the compounds. Mechanistically, PG increased the infiltration and killing activity of CD8+ T cells, which was related to the decrease of PD-1+ CD8+ T cells. Furthermore, we confirmed that PG regulated the expression of PD-1 on the surface of CD8+ T cells via reducing the secretion of VEGF-A regulated by the level of P-STAT3 in tumor cells. Additionally, PG also positively impacted the biological processes downstream of STAT3. Overall, we demonstrated that PG-mediated downregulation of PD-1 on the surface of CD8+ T cells represents a promising strategy to locally enhance T-cell responses and improve antitumor immunity.

Expression and Significance of Programmed Death-1 and Its Ligands in the Accelerated Formation of Atherosclerosis in an Induced Murine Lupus Model.

Atherosclerosis (AS) is a chronic inflammatory disease that occurs in artery walls, which seriously affects the survival and prognosis of patients with systemic lupus erythematosus (SLE). Immune and inflammatory responses have notable effects on all stages of AS. In this study, we modeled SLE combined with AS in vivo via intraperitoneal injection of pristane (2,6,10,14-tetramethylpentadecane) into apolipoprotein E-knockout (ApoE-/- ) mice that had accelerated atherosclerotic lesions compared with wild-type (WT) ApoE-/- mice. In pristane-induced ApoE-/- mice, expression of programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) in peripheral blood and on the surfaces of atherosclerotic lesions significantly increased, and levels of proinflammatory cytokines, namely, interferon-gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) in peripheral blood were elevated. We did not detect expression of programmed death-ligand 2 (PD-L2) in the arterial plaques of either pristane-induced or WT ApoE-/- mice, nor did we observe any significant difference in PD-L2 expression in peripheral blood between the two groups. Taken together, these results suggested that PD-1/PD-L1 signaling pathway might play an important regulatory role in the progression of AS in an induced murine lupus model which implies a potential target for treatment of AS in SLE.

Genomic Sequencing for Bladder Urothelial Carcinoma and Its Clinical Implications for Immunotherapy.

PurposeThis study aimed to explore the genomic and transcriptomic landscape of bladder cancer (BC) and its implication for treatment with an immune checkpoint inhibitor (ICI).Materials and MethodsWe analyzed whole-exome and -transcriptome sequences of tumor samples from 64 BC patients who underwent surgical resection with either transurethral resection or radical cystectomy. For exploratory purposes, programmed death-ligand 1 (PD-L1) expression was evaluated in a subset of patients (n=57) including those treated with ICI (n=8).ResultsWe identified frequent molecular dysregulations in chromatin regulatory genes (KDM6A, ARID1A, MLL2, and STAG2) and recurrent copy number alterations. Thirty-five samples (54.7%) were PD-L1–positive (PD-L1 combined positive score ≥ 1) with a significantly higher exonic tumor mutational burden (TMB) compared to PD-L1–negative BC samples (p=0.010). We observed that various immune-responsive pathways, including the PD-L1 signaling pathway, were enriched significantly in PD-L1–positive BCs. Interestingly, genes in the CTLA4 pathway were enriched significantly in PD-L1–positive BC as well. Among eight patients who received ICI, progressive disease was confirmed in one patient, whose tumor had low exonic TMB, negative PD-L1 status, and a relatively colder microenvironment.ConclusionGaining new insights into the molecular landscape of BC will improve treatment strategies. Our analysis suggests a rationale for studying dual checkpoint inhibition against BC.

Uncovering the Immunoregulatory Function and Therapeutic Potential of the PD-1/PD-L1 Axis in Cancer

Immune checkpoint blockade involves the targeted antagonism of immunosuppressive interactions between antigen-presenting cells and/or tumor cells and effector T cells. Blockade of B7-H1, also known as programmed death-ligand 1 (PD-L1), prevents the ligation of inhibitory PD-L1 molecules to programmed cell death receptor 1 (PD-1) on T cells, engendering a potentiated response of tumor-specific T cells against tumor cells. In a Cancer Research article, Hirano and colleagues showed that T-cell-mediated tumor immunity becomes impaired when tumor cells interact with T cells via PD-L1 in the mouse tumor microenvironment. They showed that targeting PD-L1 or PD-1 with mAbs increased tumor cell lysis by T cells and suggested that tumor PD-L1 forms a "shield" preventing tumor cell lysis. Alongside other original mouse and human studies, this work generated scientific rationales for a new generation of cancer treatment focused on targeting the inhibitory PD-1/PD-L1 signaling pathway in the tumor microenvironment.See related article by Hirano and colleagues, Cancer Res 2005;65: 1089-96.

Identification of vitamin B6 as a PD-L1 suppressor and an adjuvant for cancer immunotherapy

Interaction of programmed death-ligand 1 (PD-L1) and programmed death-1 (PD-1) inhibits T cell activation. Tumor tissues can evade immune surveillance by expressing higher levels of PD-L1. Identification of potential regulators of PD-L1 through natural metabolites may contribute to discovering new drugs for immunotherapy. By using a metabolite library screen, we showed that pyridoxal (PL) significantly suppresses PD-L1 expression. Mechanistically, PL accelerates PD-L1 degradation in a proteasome-dependent manner, and STUB1 serves as an E3 ligase during the process. Functionally, PL enhances T cell killing activity by blocking the PD-1/PD-L1 signaling pathway. Thus, we have identified PL as an inhibitor of PD-L1, which provides a feasible option for combination immunotherapy.

Nanobubbles Containing sPD-1 and Ce6 Mediate Combination Immunotherapy and Suppress Hepatocellular Carcinoma in Mice.

PurposeImmune checkpoint inhibitors (ICIs) and sonodynamic therapy (SDT) are types of immunotherapy. In order to combine soluble programmed cell death protein 1 (sPD-1)-mediated immune checkpoint therapy and chlorin e6 (Ce6)-assisted SDT, nanobubbles (NBs) were generated to simultaneously load sPD-1 and Ce6.Materials and MethodsThe sPD-1/Ce6-NBs, which were prepared by thin-film hydration and mechanical oscillation, had a stable physical condition, and delivered sPD-1 and Ce6 in a targeted manner. NBs could strengthen tumor suppression by increasing tumor-targeting accumulation of Ce6 and sPD-1, and by inducing ultrasound-targeted NB destruction. A mouse H22 cell hepatoma xenograft model was used to evaluate the synergetic immunotherapeutic effect and mechanism of sPD-1/Ce6-NBs.ResultsBy observing the tumor inhibition rate, tissue and cell apoptosis, apoptosis-related genes and protein expression, the best immunotherapeutic effect was exhibited by the sPD-1/Ce6-NBs group. The immunotherapeutic mechanism initially demonstrated that when tumor cells were transfected by sPD-1 delivered by NBs, which downregulated the expression of programmed death-ligand 1 (PD-L1) in tumor cells, and blocked the PD-1/PD-L1 signaling pathway, which improved T-cell-mediated tumor inhibition. Furthermore, ICIs combined with SDT induced immunogenic cell death by translocating calreticulin to the cell surface and then synergistically enhancing antitumor immune responses.ConclusionIn conclusion, sPD-1/Ce6-NBs were successfully designed. Ultrasound-mediated sPD-1/Ce6-NBs are potentially effective delivery systems for combination immunotherapy of hepatocellular carcinoma.

PD-L1 tumor-intrinsic signaling and its therapeutic implication in triple-negative breast cancer.

Although the immune checkpoint role of programmed death ligand 1 (PD-L1) has been established and targeted in cancer immunotherapy, the tumor-intrinsic role of PD-L1 is less appreciated in tumor biology and therapeutics development, partly because of the incomplete mechanistic understanding. Here we demonstrate a potentially novel mechanism by which PD-L1 promotes the epithelial-mesenchymal transition (EMT) in triple-negative breast cancer (TNBC) cells by suppressing the destruction of the EMT transcription factor Snail. PD-L1 directly binds to and inhibits the tyrosine phosphatase PTP1B, thus preserving p38-MAPK activity that phosphorylates and inhibits glycogen synthase kinase 3β (GSK3β). Via this mechanism, PD-L1 prevents the GSK3β-mediated phosphorylation, ubiquitination, and degradation of Snail and consequently promotes the EMT and metastatic potential of TNBC. Significantly, PD-L1 antibodies that confine the tumor-intrinsic PD-L1/Snail pathway restricted TNBC progression in immunodeficient mice. More importantly, targeting both tumor-intrinsic and tumor-extrinsic functions of PD-L1 showed strong synergistic tumor suppression effect in an immunocompetent TNBC mouse model. Our findings support that PD-L1 intrinsically facilitates TNBC progression by promoting the EMT, and this potentially novel PD-L1 signaling pathway could be targeted for better clinical management of PD-L1–overexpressing TNBCs.

The role of the programmed cell death protein-1/programmed death-ligand 1 pathway, regulatory T cells and T helper 17 cells in tumor immunity: a narrative review.

Tumor immunotherapy, especially that involving programmed cell death protein-1 (PD-1)/programmed death-ligand 1 (PD-L1) immunosuppressive checkpoint inhibitors, has become an important part of tumor treatment strategy in the past decade. Blocking PD-1/PD-L1 signaling pathway can reduce the inhibitory effect of PD-1 pathway on T cells, promote the anti-tumor activity of activated T cells, and prolong the remission period of tumor. While PD-1/PD-L1 immunotherapy is effective in the treatment of solid malignant tumors, it also has shortcomings, due to the complexity of the tumor microenvironment (TME). Regulatory T cells (Tregs) and T helper 17 (Th17) cells play an important role in the TME and are closely related to the occurrence and development of tumors. Tregs can inhibit the anti-tumor immune effect, while Th17 cells play a dual role in tumor immunity, which not only promotes tumorigenesis but also promotes anti-tumor immunity. In the occurrence and development of tumor, PD-1/PD-L1 pathway, Tregs and Th17 cells are interrelated. However, the complicated relationship between the PD-1/PD-L1 pathway, Tregs, and Th17 cells has not been fully clarified. Here, we summarize the immunoregulation mechanisms and discuss the crosstalk between the PD-1/PD-L1 pathway, Tregs, and Th17 cells, with the aim of providing novel insights for future cancer treatment.

Stimulatory and inhibitory signaling pathways of the Tcell-APC interaction and the effect of TLR agonists on APCs

CD8+ cells are key players in the identification and elimination of cancer cells. Cancers can escape an effective Tcell response by inducing an exhausted cell state, which limits the cytotoxic capacity of the effector cells. Among other mechanisms, new checkpoint inhibitors reactivate exhausted, dysfunctional Tcells. CD8+ Tcells can eliminate tumor cells after presentation of tumor-specific antigens via antigen-presenting cells (APCs). APC-mediated tumor recognition is mainly stimulated by Toll-like receptors (TLRs). This study investigates the effect of TLR agonists on APCs as well as stimulatory and inhibitory signaling pathways of the Tcell-APC interaction. Gene expression of interleukin (IL)12 and programmed death ligand1 (PD-L1) was analyzed by quantitative polymerase chain reaction (qPCR) after0, 8, 24,and 48 h of CD14+ cell stimulation with CpG. Protein expression of inhibitor of nuclear factor kappaB (IκBα) after CpG stimulation was investigated by western blot. CD8+ Tcells were stimulated for 72 h with or without programmed cell death protein1 (PD-1) checkpoint blockade and analyzed for expression of PD‑1, Tim‑3, CTLA4, and Lag3 by flow cytometry. TLR stimulation (by unmethylated CpG DNA) of APCs upregulates immunostimulatory signals such as IL12 expression but also activates immunoinhibitory signaling pathways such as PD-L1 expression. This signaling is NF-κB dependent. After blockade of the PD-1/PD-L1 signaling pathway, overexpression of other immune checkpoint inhibitory receptors was observed-apotential explanation for lacking therapeutic responses after TLR stimulation with PD‑1 checkpoint blockade. TLR stimulation causes APCs in the tumor microenvironment to upregulate PD-L1 in anNF-κB-mediated fashion, thereby contributing to CD8+ Tcell exhaustion. The effect of PD‑1 blockade after TLR stimulation might be impaired due to upregulation of other checkpoint inhibitors.

The possible regulatory effect of the PD-1/PD-L1 signaling pathway on Tregs in ovarian cancer.

Aim of this study was to investigate the possible regulatory effect of the programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) signaling pathway on Tregs in ovarian cancer. Immunohistochemistry was used to detect the expression of PD-L1 and PD-1 and the presence of FOXP3+ Tregs in ovarian cancer. Then, ovarian cancer HO8910 cells were subjected to transfection with PD-L1 siRNA in vitro. CCK-8, Transwell and wound healing assays were performed to detect the biological behaviors of ovarian cancer cells. Human T-cells isolated from human peripheral blood were cocultured with HO8910 cells, which were divided into the Control, TGF-β, and TGF-β+ anti-PD-L1 groups. The proportion of differentiated Tregs was detected by flow cytometry. Mouse models of ovarian cancer were established, and PD-L1 antibody therapy was administered. Tumor growth and Treg recruitment were observed. PD-L1, PD-1 and FOXP3+ Tregs were found in ovarian cancer tissue. Patients with tumors with an advanced stage and low differentiation and lymph node metastasis had significantly higher levels of PD-1, PD-L1 and FOXP3+ Tregs. After transfection with PD-L1 siRNA, HO8910 cells showed a significant reduction in PD-L1 expression, proliferation, migration and invasion. After T-cells were cocultured with ovarian cancer cells, the TGF-β+ anti-PD-L1 group showed a substantial decline in the differentiation of T-cells into Tregs compared with the TGF-β group. Moreover, mice in the anti-PD-L1 group had significantly reduced tumor growth rates, Treg proportions in the tumor microenvironment, and FOXP3 expression.

Inhibition of the PD-1/PD-L1 signaling pathway enhances innate immune response of alveolar macrophages to mycobacterium tuberculosis in mice

BackgroundMycobacterium tuberculosis (TB) is a pathogen that consequently leads to TB infection, which remains a significant global health concern. Programmed death 1 (PD-1)/programmed death-ligand 1 (PD-L1) signaling pathway is critical for terminating immune responses. The present study aimed to elucidate the regulatory role of the PD-1/PD-L1 signaling pathway in alveolar macrophages against Mycobacterium TB in mice. MethodsSpecific pathogen free mice were initially prepared for Mycobacterium TB model establishment. The alveolar macrophages of the successfully modeled rats were evaluated to determine the levels of PD-1, PD-L1, AKT, mTOR, TNF-α, NF-κB, IL-2, IL-4, IL-6, IL-10, IL-17, IL-17A, and IFN-γ. The surface makers of macrophages (CD11c, CD16, CD86, CD163, CD206, CX3CR-1 and CSF-1R), level of ROS, apoptosis and cell cycle, were all assessed. ResultsElevated levels of PD-1 and PD-L1, decreased levels of AKT and mTOR, along with elevated levels of TNF-α, NF-κB, IL-17, IL-2, IL-6, IL-17A and IFN-γ were identified in the alveolar macrophages infected with Mycobacterium TB, while an opposite trend was observed when PD-1/PD-L1 signaling pathway was inhibited. Additionally, elevated protein levels of CD11c, CD16 and CD86, as well as an increased rate of positive ROS and cell apoptosis, levels of Bax, and a diminished percentage of alveolar macrophages at the S and G2/M stages were detected in the event of Mycobacterium TB infection. A contrasting trend to the aforementioned findings was detected when the PD-1/PD-L1 signaling pathway was inhibited. ConclusionTaken together, these results suggested that inhibition of the PD-1/PD-L1 signaling pathway enhanced the innate immune response of alveolar macrophages to Mycobacterium TB in mice.

Programmed death-ligand 1 signaling pathway involves in bladder cancer growth and progression

CONTEXT:Exploration of the biological property of programmed death-ligand 1 (PD-L1) signaling that may impact bladder tumor growth in humanized animals and cell culture.AIMS:The aim of this study is to evaluate how PD-L1 signaling involves bladder cancer growth and progression.SETTINGS AND DESIGN:This study design involves experimental in vivo and in vivo study.SUBJECTS AND METHODS:A role of PD-L1 signaling pathway inhibition for bladder cancer growth was assessed in humanized immunodeficient animals carried main molecular subtypes of bladder carcinoma patient-derived xenografts and provided with selective anti-PD-L1 treatment; bladder cancer cells invasiveness was evaluated in mixed RT112/84 cells + CD4+ cells culture incubated with PD-L1 blocker durvalumab. We used two-tailed Student's t-test to explore differences between main and control subgroups. Significance of intergroup comparison was measured with one-way ANOVA followed by the Tukey's or Newman–Keul's criterion. Survival curves were analyzed with Gehan's criterion with the Yate's correction. Differences were considered statistically significant at P < 0.05.RESULTS:Anti-PD-L1 intervention increased survival of the animals carried both primary and relapsed luminal noninvasive, muscular invasive, and relapsed luminal bladder cancer xenografts. There was significant retardation of tumor volume duplication time in aforementioned subgroups correlated with PD-L1 expression. Durvalumab treatment in concentration-dependent manner inhibited tumor cells invasiveness of mixed RT112 + CD4+ culture cells with its maximum at the highest studied concentration (10 μM).CONCLUSIONS:Obtained data constituted the pivotal role of programmed cell death-1/PD-L1 signaling pathway in bladder cancer development and progression. The results will have major implications for further clinical investigations.

The combination of anti-KIR monoclonal antibodies with anti-PD-1/PD-L1 monoclonal antibodies could be a critical breakthrough in overcoming tumor immune escape in NSCLC.

BackgroundThe anti-programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) monoclonal antibody has a good effect in the treatment of non-small cell lung cancer (NSCLC), but not all PD-1/PD-L1 positive patients can get benefit from it. Compensatory expression of other immune checkpoints may be correlated with the poor efficacy of anti-PD-1/PD-L1 monoclonal antibodies. The inhibitory human leukocyte antigen (HLA)/killer cell Ig-like receptor (KIR) can effectively block the killing effect of natural killer (NK) cells on tumors. Our previous studies have confirmed that high expression of KIR was correlated with poor prognosis of NSCLC. Inhibitory KIR expression was positively correlated with the expression of PD-1.MethodsThe expressions of KIR 2D (L1, L3, L4, S4) (BC032422/ADQ31987/NP_002246/NP_036446, Abcam) and PD-1 (NAT 105, Cell marque) proteins was assessed by immunohistochemistry.ResultsThe expression of inhibitory KIR in tumor cells or tumor infiltrating lymphocytes (TILs) is associated with PD-1 expression. Among PD-1 positive patients, 76.3% were KIR 2D (L1, L3, L4, S4) positive on tumor cells, and 74.6% were KIR 2D (L1, L3, L4, S4) positive on TILs. We compared the expression of inhibitory KIR before and after treatment with nivolumab in 11 patients with NSCLC. We found that five (45.5%) patients had positive expression of inhibitory KIR in tumor tissue after being treated with anti-PD-1 monoclonal antibodies, two of whom exhibited a significant increase in expression of inhibitory KIR, and three showed no change.ConclusionsPD-1 expression was correlated with KIR 2D (L1, L3, L4, S4) on tumor cells or TILs. The resistance to anti-PD-1 monoclonal antibody treatment might be related to KIR. The inhibitory HLA/KIR could combine with the PD-1/PD-L1 signaling pathway negatively regulating NSCLC tumor immunity.

Percentages of PD-1+CD4+T cells and PD-L1+DCs are increased and sPD-1 level is elevated in patients with immune thrombocytopenia

ABSTRACTThe present study is to measure the expression of programmed death (PD)-1 / programmed death ligand-1 (PD-L1) negative costimulatory molecules, soluble format sPD-1 in patients with immune thrombocytopenia (ITP), and to investigate their correlation with the secretion of cytokines. A total of 35 patients with ITP were included in the present study. Twenty healthy subjects who received physical examination at our hospital were included as control group. Peripheral blood was collected from all ITP patients and healthy subjects. Flow cytometry was performed to determine the percentages of PD-1+CD4+T cells and PD-L1+DCs in ITP patients and healthy subjects. Enzyme-linked immunosorbent assay was performed to measure the concentrations of interferon (IFN)-γ, interleukin (IL)-17 and sPD-1 in peripheral blood from ITP patients and healthy subjects. Percentages of PD-1+CD4+T cells and PD-L1+DCs in peripheral blood from ITP patients before treatment were significantly higher than that from healthy subjects, but were not different from those after treatment. Serum concentrations of IFN-γ, IL-17 and sPD-1 in ITP patients before treatment were significantly higher than those in healthy subjects, and these concentrations were significantly reduced after treatment. The concentration of sPD-1 was positively correlated with the concentration of IFN-γ, and negatively correlated with platelet count. Percentages of PD-1+CD4+T cells and PD-L1+DCs in ITP patients are higher than those in healthy subjects, but elevated sPD-1 concentration in the blood blocks PD-1/PD-L1 signaling pathway, leading to unaffected Th cell function. Elevated concentrations of IFN-γ and IL-17 in the blood may participate in the occurrence and development of ITP.

Programmed death-1 and programmed death ligand-1 expressions on peripheral blood T lymphocytes from patients with condyloma acuminatum and their significance

Objective To measure the expressions of programmed death-1(PD-1)and programmed death ligand-1(PD-L1)on peripheral blood T lymphocytes of patients with condyloma acuminatum(CA), and to investigate their role in cellular immunity in these patients. Methods Peripheral blood samples were obtained from 30 patients with CA(CA group)and 20 healthy human controls(control group). Flow cytometry was conducted to detect the expressions of PD-1 and PD-L1 on the surfaces of peripheral blood CD4+ and CD8+ T lymphocytes, and to determine the counts of CD4+ and CD8+ T lymphocytes. Enzyme-linked immunosorbent assay(ELISA)was performed to measure the levels of serum interleukin-2(IL-2)and interferon-γ(IFN-γ). Statistical analyses were carried out to compare the above parameters between the two groups, and to assess the relationship of PD-1 and PD-L1 expressions with the counts of CD4+ and CD8+ T lymphocytes as well as with the serum levels of IL-2 and IFN-γ. Results There was a significant increase in the expression rates of PD-1 and PD-L1 on CD4+ T lymphocytes(PD-1: 9.48% ± 3.31% vs. 7.12% ± 2.16%, t = 2.81, P 0.05). The levels of serum IL-2 and IFN-γ were both lower in the CA group than in the control group(t = 2.12, 2.16, respectively, both P 0.05). Conclusion PD-1 was highly expressed on peripheral blood T lymphocytes from patients with CA, which may inhibit T lymphocyte-mediated immune response, decrease CD4+ T lymphocyte counts, the CD4/CD8 ratio as well as IL-2 and IFN-γ serum levels by interacting with its ligand PD-L1 and forming the PD-1/PD-L1 signaling pathway. Key words: Condylomata acuminata; T-lymphocytes; Programmed death-1; Programmed death ligand-1