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.

[Alpha-momordicin Regulates Hepatocyte Cytokine Expression].

OBJECTIVE: To investigate the regulation effect of α-momordicin (α-MMC) on the synthesis and secretion of cytokines in hepatocytes cells. METHODS: Hepatocytes L02 were treated with 189 µg/mL α-MMC with culture supernatant and lysate samples were harvested in different timepoint. Expressions of T-helper 17 (TH17) cytokine profile in samples were detected by the Bio-Plex 200 suspension chip assay system. RESULTS: Compared with 0 h, after the α-MMC treatment of L02 hepatocytes for 2 h, 4 h and 8 h, the intracellular synthesis of cytokines interleukin (IL)-1b, IL-6, IL-17A, IL-31, IL-33, soluble CD40 ligand (sCD40L), tumor necrosis factor-α (TNF-α) were all significantly decreased (P<0.05), and IL-6, IL-4, IL-17A, and sCD40L secreted into the extracellular fluid also decreased significantly (P<0.05). CONCLUSION: α-MMC can significantly inhibit the synthesis and secretion of cytokines such as IL-6, IL-17A and TNF-α in hepatocytes, which may become a side effect of its anti-tumor application.

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.