CD39hi identifies an exhausted tumor-reactive CD8+ T cell population associated with tumor progression in human gastric cancer.

The ectonucleotidase CD39 has been regarded as a promising immune checkpoint in solid tumors. However, the expression of CD39 by tumor-infiltrating CD8+ T cells as well as their potential roles and clinical implications in human gastric cancer (GC) remain largely unknown. Here, we found that GC-infiltrating CD8+ T cells contained a fraction of CD39hi cells that constituted about 6.6% of total CD8+ T cells in tumors. These CD39hi cells enriched for GC-infiltrating CD8+ T cells with features of exhaustion in transcriptional, phenotypic, metabolic and functional profiles. Additionally, GC-infiltrating CD39hiCD8+ T cells were also identified for tumor-reactive T cells, as these cells expanded in vitro were able to recognize autologous tumor organoids and induced more tumor cell apoptosis than those of expanded their CD39int and CD39-CD8+ counterparts. Furthermore, CD39 enzymatic activity controlled GC-infiltrating CD39hiCD8+ T cell effector function, and blockade of CD39 efficiently enhanced their production of cytokines IFN-γ and TNF-α. Finally, high percentages of GC-infiltrating CD39hiCD8+ T cells correlated with tumor progression and independently predicted patients' poor overall survival. These findings provide novel insights into the association of CD39 expression level on CD8+ T cells with their features and potential clinical implications in GC, and empowering those exhausted tumor-reactive CD39hiCD8+ T cells through CD39 inhibition to circumvent the suppressor program may be an attractive therapeutic strategy against GC.

Distribution, phenotype, functional and clinical relevance of CD8+CD103+ tissue-resident memory T cells in human gastric cancer.

CD8+CD103+ tissue-resident memory T cells (TRMs) are involved in tumor immune response and linked to favorable clinical outcome in human cancer. However, the distribution, phenotype, functional properties and clinical relevance of these cells in gastric cancer (GC) remain elusive. Here, our data show that, in comparison to non-tumor tissues, the percentages of CD8+CD103+ TRMs in tumors are significantly decreased. Most tumor-infiltrating CD8+CD103+ TRMs are CD45RA-CCR7- effector-memory cells with higher PD-1 and 4-1BB expression than those from non-tumor tissues. Further, tumor-infiltrating CD8+CD103+ TRMs show impaired cytolytic capacity due to decreased granzyme B and perforin expression. Moreover, ex vivo PD-1 blockade could restore the cytolytic capacity of tumor-infiltrating CD8+CD103+ TRMs, and such anti-PD-1-mediated reinvigoration of CD8+CD103+ TRMs could be further enhanced by 4-1BB co-stimulation. Finally, lower levels of Tumor-infiltrating CD8+CD103+ TRMs are positively correlated with GC progression and poor patients' survival. Our data suggest that restoring CD8+CD103+ TRM function by combining PD-1 blockade and 4-1BB co-stimulation may be a promising strategy for treating GC.

Expression, regulation and clinical significance of B7-H3 on neutrophils in human gastric cancer.

Neutrophils are conspicuous components of gastric cancer (GC) tumors, increasing with tumor progression and poor patient survival. However, the phenotype, regulation and clinical relevance of neutrophils in human GC are presently unknown. Most intratumoral neutrophils showed an activated CD54+ phenotype and expressed high level B7-H3. Tumor tissue culture supernatants from GC patients induced the expression of CD54 and B7-H3 on neutrophils in time-dependent and dose-dependent manners. Locally enriched CD54+ neutrophils and B7-H3+ neutrophils positively correlated with increased granulocyte-macrophage colony stimulating factor (GM-CSF) detection ex vivo; and in vitro GM-CSF induced the expression of CD54 and B7-H3 on neutrophils in both time-dependent and dose-dependent manners. Furthermore, GC tumor-derived GM-CSF activated neutrophils and induced neutrophil B7-H3 expression via JAK-STAT3 signaling pathway activation. Finally, intratumoral B7-H3+ neutrophils increased with tumor progression and independently predicted reduced overall survival. Collectively, these results suggest B7-H3+ neutrophils to be potential biomarkers in GC.

Helicobacter pylori-induced REDD1 modulates Th17 cell responses that contribute to gastritis.

OBJECTIVE: Regulated in development and DNA damage responses-1 (REDD1) is a conserved and ubiquitous protein, which is induced in response to multiple stimuli. However, the regulation, function and clinical relevance of REDD1 in Helicobacter pylori-associated gastritis are presently unknown. APPROACH: Immunohistochemistry, real-time PCR and Western blot analyses were performed to examine the levels of REDD1 in gastric samples from H. pylori-infected patients and mice. Gastric tissues from Redd1-/- and wildtype (WT, control) mice were examined for inflammation. Gastric epithelial cells (GECs), monocytes and T cells were isolated, stimulated and/or cultured for REDD1 regulation and functional assays. RESULTS: REDD1 was increased in gastric mucosa of H. pylori-infected patients and mice. H. pylori induced GECs to express REDD1 via the phosphorylated cytotoxin associated gene A (cagA) that activated MAPKp38 pathway to mediate NF-κB directly binding to REDD1 promoter. Human gastric REDD1 increased with the severity of gastritis, and mouse REDD1 from non-marrow chimera-derived cells promoted gastric inflammation that was characterized by the influx of MHCII+ monocytes. Importantly, gastric inflammation, MHCII+ monocyte infiltration, IL-23 and IL-17A were attenuated in Redd1-/- mice. Mechanistically, REDD1 in GECs regulated CXCL1 production, which attracted MHCII+ monocytes migration by CXCL1-CXCR2 axis. Then H. pylori induced MHCII+ monocytes to secrete IL-23, which favored IL-17A-producing CD4+ cell (Th17 cell) polarization, thereby contributing to the development of H. pylori-associated gastritis. CONCLUSIONS: The present study identifies a novel regulatory network involving REDD1, which collectively exert a pro-inflammatory effect within gastric microenvironment. Efforts to inhibit this REDD1-dependent pathway may prove valuable strategies in treating of H. pylori-associated gastritis.

Upexpression of BHLHE40 in gastric epithelial cells increases CXCL12 production through interaction with p-STAT3 in Helicobacter pylori-associated gastritis.

BHLHE40, a member of the basic helix-loop-helix transcription factor family, has been reported to play an important role in inflammatory diseases. However, the regulation and function of BHLHE40 in Helicobacter pylori (H pylori)-associated gastritis is unknown. We observed that gastric BHLHE40 was significantly elevated in patients and mice with H pylori infection. Then, we demonstrate that H pylori-infected GECs express BHLHE40 via cagA-ERK pathway. BHLHE40 translocates to cell nucleus, and then binds to cagA protein-activated p-STAT3 (Tyr705). The complex increases chemotactic factor CXCL12 expression (production). Release of CXCL12 from GECs fosters CD4+ T cell infiltration in the gastric mucosa. Our results identify the cagA-BHLHE40-CXCL12 axis that contributes to inflammatory response in gastric mucosa during H pylori infection.

Abrogation of cathepsin C by Helicobacter pylori impairs neutrophil activation to promote gastric infection.

Cathepsin C (CtsC) functions as a central coordinator for activation of many serine proteases in immune cells. However, CtsC expression in gastric epithelial cells and its role in Helicobacter pylori infection remain unclear. Real-time PCR, Western blot, and immunohistochemistry analyses identified that CtsC was decreased in gastric mucosa of H. pylori-infected patients and mice. Isolated gastric epithelial cells and cell lines were stimulated with H. pylori and/or TGF-ß1 showed that down-regulation of CtsC in gastric epithelial cells largely depended on H. pylori cagA via Src/ERK and Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathways, and the effect could be synergistically augmented by TGF-ß1 in an autocrine manner. In human gastric mucosa, CtsC expression was negatively correlated with bacteria colonization; accordingly, provision of exogenous active CtsC overwhelmed H. pylori persistence in gastric mucosa of mice. In the presence of active CtsC, isolated human neutrophils activated via NF-κB pathway with augmented bactericidal capacity in vitro. We also found that neutrophils activated and cleared bacteria in active CtsC-injected mice and that there was no bactericidal capacity in mice that were simultaneously neutrophil-depleted by Ly6G antibody. Our findings identified a mechanism that H. pylori abrogate CtsC to impair neutrophil activation and to ensure persistence in gastric mucosa. Efforts to enable and boost this neutrophil activation pathway by active CtsC may therefore become valuable strategies in treating H. pylori infection.-Liu, Y. G., Teng, Y. S., Cheng, P., Kong, H., Lv, Y. P., Mao, F. Y., Wu, X. L., Hao, C. J., Chen, W., Yang, S. M., Zhang, J. Y., Peng, L. S., Wang, T. T., Han, B., Ma, Q., Zou, Q. M., Zhuang, Y. Abrogation of cathepsin C by Helicobacter pylori impairs neutrophil activation to promote gastric infection.

Tumour-activated neutrophils in gastric cancer foster immune suppression and disease progression through GM-CSF-PD-L1 pathway.

OBJECTIVE: Neutrophils are prominent components of solid tumours and exhibit distinct phenotypes in different tumour microenvironments. However, the nature, regulation, function and clinical relevance of neutrophils in human gastric cancer (GC) are presently unknown. DESIGN: Flow cytometry analyses were performed to examine levels and phenotype of neutrophils in samples from 105 patients with GC. Kaplan-Meier plots for overall survival were performed using the log-rank test. Neutrophils and T cells were isolated, stimulated and/or cultured for in vitro and in vivo regulation and function assays. RESULTS: Patients with GC showed a significantly higher neutrophil infiltration in tumours. These tumour-infiltrating neutrophils showed an activated CD54+ phenotype and expressed high level immunosuppressive molecule programmed death-ligand 1 (PD-L1). Neutrophils activated by tumours prolonged their lifespan and strongly expressed PD-L1 proteins with similar phenotype to their status in GC, and significant correlations were found between the levels of PD-L1 and CD54 on tumour-infiltrating neutrophils. Moreover, these PD-L1+ neutrophils in tumours were associated with disease progression and reduced GC patient survival. Tumour-derived GM-CSF activated neutrophils and induced neutrophil PD-L1 expression via Janus kinase (JAK)-signal transducer and activator of transcription 3 (STAT3) signalling pathway. The activated PD-L1+ neutrophils effectively suppressed normal T-cell immunity in vitro and contributed to the growth and progression of human GC in vivo; the effect could be reversed by blocking PD-L1 on these neutrophils. CONCLUSIONS: Our results illuminate a novel mechanism of PD-L1 expression on tumour-activated neutrophils in GC, and also provide functional evidence for these novel GM-CSF-PD-L1 pathways to prevent, and to treat this immune tolerance feature of GC.

A pro-inflammatory role for Th22 cells in Helicobacter pylori-associated gastritis.

OBJECTIVE: Helper T (Th) cell responses are critical for the pathogenesis of Helicobacter pylori-induced gastritis. Th22 cells represent a newly discovered Th cell subset, but their relevance to H. pylori-induced gastritis is unknown. DESIGN: Flow cytometry, real-time PCR and ELISA analyses were performed to examine cell, protein and transcript levels in gastric samples from patients and mice infected with H. pylori. Gastric tissues from interleukin (IL)-22-deficient and wild-type (control) mice were also examined. Tissue inflammation was determined for pro-inflammatory cell infiltration and pro-inflammatory protein production. Gastric epithelial cells and myeloid-derived suppressor cells (MDSC) were isolated, stimulated and/or cultured for Th22 cell function assays. RESULTS: Th22 cells accumulated in gastric mucosa of both patients and mice infected with H. pylori. Th22 cell polarisation was promoted via the production of IL-23 by dendritic cells (DC) during H. pylori infection, and resulted in increased inflammation within the gastric mucosa. This inflammation was characterised by the CXCR2-dependent influx of MDSCs, whose migration was induced via the IL-22-dependent production of CXCL2 by gastric epithelial cells. Under the influence of IL-22, MDSCs, in turn, produced pro-inflammatory proteins, such as S100A8 and S100A9, and suppressed Th1 cell responses, thereby contributing to the development of H. pylori-associated gastritis. CONCLUSIONS: This study, therefore, identifies a novel regulatory network involving H. pylori, DCs, Th22 cells, gastric epithelial cells and MDSCs, which collectively exert a pro-inflammatory effect within the gastric microenvironment. Efforts to inhibit this Th22-dependent pathway may therefore prove a valuable strategy in the therapy of H. pylori-associated gastritis.

CD39 expression defines exhausted CD4+ T cells associated with poor survival and immune evasion in human gastric cancer.

Objectives: CD4+ T cell helper and regulatory function in human cancers has been well characterised. However, the definition of tumor-infiltrating CD4+ T cell exhaustion and how it contributes to the immune response and disease progression in human gastric cancer (GC) remain largely unknown. Methods: A total of 128 GC patients were enrolled in the study. The expression of CD39 and PD-1 on CD4+ T cells in the different samples was analysed by flow cytometry. GC-infiltrating CD4+ T cell subpopulations based on CD39 expression were phenotypically and functionally assessed. The role of CD39 in the immune response of GC-infiltrating T cells was investigated by inhibiting CD39 enzymatic activity. Results: In comparison with CD4+ T cells from the non-tumor tissues, significantly more GC-infiltrating CD4+ T cells expressed CD39. Most GC-infiltrating CD39+CD4+ T cells exhibited CD45RA-CCR7- effector-memory phenotype expressing more exhaustion-associated inhibitory molecules and transcription factors and produced less TNF-α, IFN-γ and cytolytic molecules than their CD39-CD4+ counterparts. Moreover, ex vivo inhibition of CD39 enzymatic activity enhanced their functional potential reflected by TNF-α and IFN-γ production. Finally, increased percentages of GC-infiltrating CD39+CD4+ T cells were positively associated with disease progression and patients' poorer overall survival. Conclusion: Our study demonstrates that CD39 expression defines GC-infiltrating CD4+ T cell exhaustion and their immunosuppressive function. Targeting CD39 may be a promising therapeutic strategy for treating GC patients.

Helicobacter pylori-Induced Angiopoietin-Like 4 Promotes Gastric Bacterial Colonization and Gastritis.

Helicobacter pylori infection is characterized as progressive processes of bacterial persistence and chronic gastritis with features of infiltration of mononuclear cells more than granulocytes in gastric mucosa. Angiopoietin-like 4 (ANGPTL4) is considered a double-edged sword in inflammation-associated diseases, but its function and clinical relevance in H. pylori-associated pathology are unknown. Here, we demonstrate both pro-colonization and pro-inflammation roles of ANGPTL4 in H. pylori infection. Increased ANGPTL4 in the infected gastric mucosa was produced from gastric epithelial cells (GECs) synergistically induced by H. pylori and IL-17A in a cagA-dependent manner. Human gastric ANGPTL4 correlated with H. pylori colonization and the severity of gastritis, and mouse ANGPTL4 from non-bone marrow-derived cells promoted bacteria colonization and inflammation. Importantly, H. pylori colonization and inflammation were attenuated in Il17a -/-, Angptl4 -/-, and Il17a -/- Angptl4 -/- mice. Mechanistically, ANGPTL4 bound to integrin αV (ITGAV) on GECs to suppress CXCL1 production by inhibiting ERK, leading to decreased gastric influx of neutrophils, thereby promoting H. pylori colonization; ANGPTL4 also bound to ITGAV on monocytes to promote CCL5 production by activating PI3K-AKT-NF-κB, resulting in increased gastric influx of regulatory CD4+ T cells (Tregs) via CCL5-CCR4-dependent migration. In turn, ANGPTL4 induced Treg proliferation by binding to ITGAV to activate PI3K-AKT-NF-κB, promoting H. pylori-associated gastritis. Overall, we propose a model in which ANGPTL4 collectively ensures H. pylori persistence and promotes gastritis. Efforts to inhibit ANGPTL4-associated pathway may prove valuable strategies in treating H. pylori infection.

CD8(+) T cells that produce interleukin-17 regulate myeloid-derived suppressor cells and are associated with survival time of patients with gastric cancer.

BACKGROUND & AIMS: CD8(+) T cells that produce interleukin (IL)-17 (Tc17 cells) promote inflammation and have been identified in tumors. We investigated their role in the pathogenesis of gastric cancer. METHODS: We used flow cytometry analyses to determine levels and phenotype of Tc17 cells in blood and tumor samples from 103 patients with gastric cancer. We performed multivariate analysis to identify factors associated with overall survival using the Cox proportional hazards model. CD8(+) T cells and monocytes were isolated and cocultured in an assay for induction of Tc17 cells. Tumor cells and myeloid-derived suppressor cells (MDSCs) were isolated and used in assays of Tc17 cell function. RESULTS: Tc17 cells with distinct cytokine and functional profiles were found in gastric tumor samples from patients. The percentage of Tc17 cells increased with tumor progression and was associated with overall survival time. Tumor-activated monocytes secreted IL-6, IL-1ß, and IL-23, which promoted development of Tc17 cell populations. Supernatants from cultured Tc17 cells induced production of the chemokine CXCL12 by tumor cells; this promoted CXCR4-dependent migration of MDSCs and impaired functions of anti-tumor CD8(+) cytotoxic T cells via a cell contact-dependent mechanism. CONCLUSIONS: Percentages of Tc17 cells in gastric tumors are associated with survival times of patients. These cells promote chemotaxis of MDSCs, which might promote tumor progression.

Role of gamma-delta T cells in host response against Staphylococcus aureus-induced pneumonia.

BACKGROUND: Staphylococcus aureus is the major cause of hospital-acquired and community-acquired pneumonia. Host defense to S.aureus infection is largely mediated by the innate immune system. γδ T cells play an important role in innate immunity to many infectious diseases. However, less is known about the role of these cells during S.aureus-induced pneumonia. In this study, we examined the response and the role of γδ T cells to pulmonary S.aureus infection. RESULTS: Mice infected with S. aureus intranasally showed rapid γδ T cells accumulation in the lung. Deficiency of γδ T cells led to attenuated bacterial clearance and less tissue damage in lung compared with WT mice. Moreover, TCR-δ-/- mice exhibited impaired neutrophil recruitment and reduced cytokine production at the site of infection. The γδ T cells in response to pulmonary S. aureus infection mainly secreted IL-17 and γδ T cells deficiency reduced IL-17 production, which might regulate the production of neutrophil-inducing cytokine/chemokine in the S. aureus-infected lungs. CONCLUSIONS: Accumulation of γδ T cells in the lungs to S. aureus infection is beneficial for bacteria clearance and also contributes to the tissue damage. These cells were the primary source of IL-17, which might influence the recruitment of neutrophils at the early stage of infection.

Increased intratumoral IL-22-producing CD4(+) T cells and Th22 cells correlate with gastric cancer progression and predict poor patient survival.

IL-22-producing CD4(+) T cells (IL-22(+)CD4(+) T cells) and Th22 cells (IL-22(+)IL-17(-)IFN-γ(-)CD4(+) T cells) represent newly discovered T-cell subsets, but their nature, regulation, and clinical relevance in gastric cancer (GC) are presently unknown. In our study, the frequency of IL-22(+)CD4(+) T cells in tumor tissues from 76 GC patients was significantly higher than that in tumor-draining lymph nodes, non-tumor, and peritumoral tissues. Most intratumoral IL-22(+)CD4(+) T cells co-expressed IL-17 and IFN-γ and showed a memory phenotype. Locally enriched IL-22(+)CD4(+) T cells positively correlated with increased CD14(+) monocytes and IL-6 and IL-23 detection ex vivo, and in vitro IL-6 and IL-23 induced the polarization of IL-22(+)CD4(+) T cells in a dose-dependent manner and the polarized IL-22(+)CD4(+) T cells co-expressed of IL-17 and IFN-γ. Moreover, IL-22(+)CD4(+) T-cell subsets (IL-22(+)IL-17(+)CD4(+), IL-22(+)IL-17(-)CD4(+), IL-22(+)IFN-γ(+)CD4(+), IL-22(+)IFN-γ(-)CD4(+), and IL-22(+)IL-17(+)IFN-γ(+)CD4(+) T cells), and Th22 cells were also increased in tumors. Furthermore, higher intratumoral IL-22(+)CD4(+) T-cell percentage and Th22-cell percentage were found in patients with tumor-node-metastasis stage advanced and predicted reduced overall survival. In conclusion, our data indicate that IL-22(+)CD4(+) T cells and Th22 cells are likely important in establishing the tumor microenvironment for GC; increased intratumoral IL-22(+)CD4(+) T cells and Th22 cells are associated with tumor progression and predict poorer patient survival, suggesting that tumor-infiltrating IL-22(+)CD4(+) T cells and Th22 cells may be suitable therapeutic targets in patients with GC.

Increased tumor-infiltrating CD8(+)Foxp3(+) T lymphocytes are associated with tumor progression in human gastric cancer.

BACKGROUND: CD8(+)Foxp3(+) T lymphocytes have been detected in tumors. However, the distribution, phenotypic features, and regulation of these cells in gastric cancer remain unknown. METHODS: The levels of CD8(+)Foxp3(+) T lymphocytes in the peripheral blood, tumor-draining lymph nodes, non-tumor tissues, and tumor tissues of patients with gastric cancer were detected by flow cytometry. Foxp3 induction in CD8(+)Foxp3(-) T cells was investigated in vitro. The suppressive function of CD8(+)Foxp3(+) T lymphocytes was analyzed by their effect on CD4(+) T-cell proliferation and IFN-γ production. The percentages of CD8(+)Foxp3(+) T lymphocytes were evaluated for the association with tumor stage. RESULTS: The frequency of CD8(+)Foxp3(+) T lymphocytes in tumor tissues was significantly higher than that in non-tumor tissues, and similar results were also observed in tumor-draining lymph nodes compared with peripheral blood. Most intratumoral CD8(+)Foxp3(+) T lymphocytes were activated effector cells (CD45RA(-)CD27(-)). TGF-ß1 levels were positively correlated with the frequency of CD8(+)Foxp3(+) T lymphocytes in tumor tissues, and in vitro TGF-ß1 could induce the generation of CD8(+)Foxp3(+) T lymphocytes in a dose-dependent manner. Furthermore, intratumoral CD8(+)Foxp3(+) T lymphocytes suppressed the proliferation and IFN-γ production of CD4(+) T cells. Finally, intratumoral CD8(+)Foxp3(+) T lymphocytes were significantly increased with tumor progression in terms of tumor-node-metastasis (TNM) stage. CONCLUSIONS: Our data have shown that increased intratumoral CD8(+)Foxp3(+) T lymphocytes are associated with tumor stage and potentially influence CD4(+) T-cell functions, which may provide insights for developing novel immunotherapy protocols against gastric cancer.

Helicobacter pylori HP0876 is dispensable for heme-iron acquisition but attenuates bacterial adherence to gastric epithelial cells.

Helicobacter pylori can efficiently capture iron either from free heme or heme-containing compounds in the iron-limited gastric mucosa. However, the heme iron utilization systems of H. pylori have not been fully described to date. To investigate the contribution of genes involved in heme-iron utilization, a gene homologous to frpB, encode by hp0876 in H. pylori ATCC 26695, was inactivated by homologous recombination. Δhp0876 showed no demonstrable growth defects in the presence of the various concentrations of free iron. Moreover, when hemoglobin or heme was supplied as the sole iron sources, Δhp0876 had growth curves similar to the wild-type strain. The growth competition experiments in vitro also showed that Δhp0876 retained the ability for iron acquisition. Furthermore, IL-8 production in human gastric epithelial cells co-cultured with Δhp0876 and wild-type strain was compared, and our results indicated that lack of HP0876 affected the IL-8 release. And Δhp0876 exhibited significantly increased adherence to gastric epithelial cells. Together, our data suggests that HP0876 is dispensable for H. pylori heme-iron uptake, but it may attenuate H. pylori adherence to gastric epithelial cells, which induced decreased production of H. pylori-induced IL-8 production in gastric epithelial cells.

FasL+ PD-L2+ Identifies a Novel Immunosuppressive Neutrophil Population in Human Gastric Cancer That Promotes Disease Progression.

Neutrophils constitute abundant cellular components in human gastric cancer (GC) tissues, but their protumorigenic subset in pathogenesis of GC progression is unclear. Here, it is found that patients with GC show significantly higher neutrophil infiltration in tumors that is regulated by CXCL12-CXCR4 chemotaxis. These tumor-infiltrating neutrophils express high level immunosuppressive molecules FasL and PD-L2, and this FasL+ PD-L2+ neutrophil subset with a unique phenotype constitutes at least 20% of all neutrophils in advanced GC and predicts poor patient survival. Tumor induces neutrophils to express FasL and PD-L2 proteins with similar phenotype to those in GC tumors in both time-dependent and dose-dependent manners. Mechanistically, Th17 cell-derived IL-17A and tumor cell-derived G-CSF can significantly induce neutrophil FasL and PD-L2 expression via activating ERK-NF-κB and JAK-STAT3 signaling pathway, respectively. Importantly, upon over-expressing FasL and PD-L2, neutrophils acquire immunosuppressive functions on tumor-specific CD8+ T-cells and promote the growth and progression of human GC tumors in vitro and in vivo, which can be reversed by blocking FasL and PD-L2 on these neutrophils. Thus, the work identifies a novel protumorigenic FasL+ PD-L2+ neutrophil subset in GC and provides new insights for human cancer immunosuppression and anti-cancer therapies targeting these pathogenic cells.

Evaluation of a recombinant five-antigen Staphylococcus aureus vaccine: The randomized, single-centre phase 1a/1b clinical trials.

BACKGROUND: Staphylococcus aureus is an important pathogen that causes hospital and community infections. To control Staphylococcus aureus infection and reduce the usage of antibiotics, we evaluated the safety and immunogenicity of a recombinant five-antigen Staphylococcus aureus vaccine (rFSAV) in healthy adults. METHODS: We conducted a randomized, double-blind, placebo-controlled phase 1a study and a randomized, open-label phase 1b study. In phase 1a, we randomly allocated 144 healthy participants in a ratio of 1:1:1:1 to receive the low-(60 µg), middle-(120 µg), and high-dose (240 µg) vaccine or placebo at day 0, 3, 7 and 14. In phase 1b, 144 healthy participants were randomly allocated at a ratio of 1:1:1:1 to receive 0-3-7, 0/0-7, 0/0-3-7, 0/0-7-14 regimens to estimate the optimal strategy. The primary study endpoint was the incidence of solicited adverse events post-vaccination. The immunogenicity endpoints included the level of specific antibodies to five antigens after vaccination, as well as the cellular immune responses and functional antibodies. RESULTS: There were 31 (86%), 30 (83%), and 32 (89%) of 36 participants in the low-, middle-, and high-dose group reported solicited adverse events, respectively, most of the adverse events were mild or moderate. In phase 1b, the dose-adjusted rFSAV (90 µg) showed a better safety profile in the four immune procedures, and no vaccine-related serious adverse events were reported. The antigen-specific binding antibodies started to increase at day 7 and reached the peak around day 14 to 21. The cellular immune responses and functional antibodies also were substantially above background levels. CONCLUSIONS: rFSAV is safe, well tolerated in healthy adults, elicits rapid and robust specific humoral and cellular immune responses with unconventional immunization procedure in phase 1a and 1b. It deserves to be noted and further explored. CLINICAL TRIALS REGISTRATION: NCT02804711 and NCT03966040.

Granulocyte-Macrophage Colony-Stimulating Factor-Activated Neutrophils Express B7-H4 That Correlates with Gastric Cancer Progression and Poor Patient Survival.

Neutrophils are prominent components of gastric cancer (GC) tumors and exhibit distinct phenotypes in GC environment. However, the phenotype, regulation, and clinical relevance of neutrophils in human GC are presently unknown. Here, immunohistochemistry, real-time PCR, and flow cytometry analyses were performed to examine levels and phenotype of neutrophils in samples from 41 patients with GC, and also isolated, stimulated, and/or cultured neutrophils for in vitro regulation assays. Finally, we performed Kaplan-Meier plots for overall survival by using the log-rank test to evaluate the clinical relevance of neutrophils and their subsets. In our study, neutrophils in tumor tissues were significantly higher than those in nontumor tissues and were positively associated with tumor progression but negatively correlated with GC patient survival. Most intratumoral neutrophils showed an activated CD54+ phenotype and expressed high-level immunosuppressive molecule B7-H4. Tumor tissue culture supernatants from GC patients induced neutrophils to express CD54 and B7-H4 in both time-dependent and dose-dependent manners. Locally enriched CD54+ neutrophils and B7-H4+ neutrophils positively correlated with increased granulocyte-macrophage colony-stimulating factor (GM-CSF) detection ex vivo, and in vitro GM-CSF induced the expression of CD54 and B7-H4 on neutrophils in a time-dependent and dose-dependent manner. Moreover, GC tumor-derived GM-CSF activated neutrophils and induced neutrophil B7-H4 expression via Janus kinase (JAK)-signal transducer and activator of transcription 3 (STAT3) signaling pathway activation. Furthermore, higher intratumoral B7-H4+ neutrophil percentage/number was found in GC patients with advanced tumor node metastasis stage and reduced overall survival following surgery. Our results illuminate a novel regulating mechanism of B7-H4 expression on tumor-activated neutrophils in GC, suggesting that functional inhibition of these novel GM-CSF-B7-H4 pathways may be a suitable therapeutic strategy to treat the immune tolerance feature of GC.

L-Plastin Promotes Gastric Cancer Growth and Metastasis in a Helicobacter pylori cagA-ERK-SP1-Dependent Manner.

Actin cytoskeleton dynamic rearrangement is required for tumor cell metastasis and is a key characteristic of Helicobacter pylori (H. pylori)-infected host cells. Actin cytoskeleton modulation is coordinated by multiple actin-binding proteins (ABP). Through Kyoto encyclopedia of gene and genomes database, GEPIA website, and real-time PCR data, we found that H. pylori infection significantly induced L-plastin, a key ABP, in gastric cancer cells. We further explored the regulation and function of L-plastin in H. pylori-associated gastric cancer and found that, mechanistically, H. pylori infection induced gastric cancer cells to express L-plastin via cagA-activated ERK signaling pathway to mediate SP1 binding to L-plastin promoter. Moreover, this increased L-plastin promoted gastric cancer cell proliferation and migration in vitro and facilitated the growth and metastasis of gastric cancer in vivo. Finally, we detected the expression pattern of L-plastin in gastric cancer tissues, and found that L-plastin was increased in gastric cancer tissues and that this increase of L-plastin positively correlated with cagA + H. pylori infection status. Overall, our results elucidate a novel mechanism of L-plastin expression induced by H. pylori, and a new function of L-plastin-facilitated growth and metastasis of gastric cancer, and thereby implicating L-plastin as a potential therapeutic target against gastric cancer. IMPLICATIONS: Our results elucidate a novel mechanism of L-plastin expression induced by H. pylori in gastric cancer, and a new function of L-plastin-facilitated gastric cancer growth and metastasis, implicating L-plastin as a potential therapeutic target against gastric cancer.

Activated neutrophils polarize protumorigenic interleukin-17A-producing T helper subsets through TNF-α-B7-H2-dependent pathway in human gastric cancer.

RATIONALE: Neutrophils constitute massive cellular constituents in inflammatory human gastric cancer (GC) tissues, but their roles in pathogenesis of inflammatory T helper (Th) subsets are still unknown. METHODS: Flow cytometry analysis and immunohistochemistry were used to analyze the responses and phenotypes of neutrophils in different samples from 51 patients with GC. Kaplan-Meier plots and Multivariate analysis for the survival of patients were used by log-rank tests and Cox proportional hazards models. Neutrophils and CD4+ T cells were purified and cultured for ex vivo, in vitro and in vivo regulation and function assays. RESULTS: GC patients exhibited increased tumoral neutrophil infiltration with GC progression and poor patient prognosis. Intratumoral neutrophils accumulated in GC tumors via CXCL6/CXCL8-CXCR1-mediated chemotaxis, and expressed activated molecule CD54 and co-signaling molecule B7-H2. Neutrophils induced by tumors strongly expressed CD54 and B7-H2 in both dose- and time-dependent manners, and a close correlation was obtained between the expressions of CD54 and B7-H2 on intratumoral neutrophils. Tumor-derived tumor necrosis factor-α (TNF-α) promoted neutrophil activation and neutrophil B7-H2 expression through ERK-NF-κB pathway, and a significant correlation was found between the levels of TNF-α and CD54+ or B7-H2+ neutrophils in tumor tissues. Tumor-infiltrating and tumor-conditioned neutrophils effectively induced IL-17A-producing Th subset polarization through a B7-H2-dependent manner ex vivo and these polarized IL-17A-producing Th cells exerted protumorigenic roles by promoting GC tumor cell proliferation via inflammatory molecule IL-17A in vitro, which promoted the progression of human GC in vivo; these effects could be reversed when IL-17A is blocked. Moreover, increased B7-H2+ neutrophils and IL-17A in tumors were closely related to advanced GC progression and predicted poor patient survival. CONCLUSION: We illuminate novel underlying mechanisms that TNF-α-activated neutrophils link B7-H2 to protumorigenic IL-17A-producing Th subset polarization in human GC. Blocking this pathological TNF-α-B7-H2-IL-17A pathway may be useful therapeutic strategies for treating GC.