Summary

However, in vitro-activated B cells downregulated CD73 expression, mainly produced 59-AMP, and inhibited T-cell proliferation and cytokine production. These B cells acquire the ability to restrict potentially harmful effects of activated T cells. Thus, B cells emerge as a key regulatory component of T cell-B cell interactions, and their dual regulatory activity is mediated by the products of ATP hydrolysis, 59-AMP, and ADO. (Blood. 2013;122(1):9-18)

Purpose Regulatory T cells (Treg) accumulate in tumor tissues and the peripheral blood of cancer patients and may persist after therapies. This cross-sectional study examines effects of adjuvant chemo-radiotherapy (CRT) on Treg numbers and function in head and neck squamous cell carcinoma (HNSCC) patients. Experimental design The frequency and absolute numbers of CD4+, ATP-hydrolyzing CD4+CD39+ and CD8+ T cells and expression levels of CD39, CD25, TGF-β-associated LAP and GARP on Treg were measured by flow cytometry in 40 healthy donors (NC) and 71 HNSCC patients (29 untreated with active disease (AD); 22 treated with surgery; 20 treated with CRT). All treated subjects had no evident disease (NED) at the time of phlebotomy. In an additional cohort of 40 subjects with AD (n=15), NED (n=10) and NC (n=15), in vitro sensitivity of CD4+ T cell subsets to cisplatin and activation-induced cell death (AICD) was tested in Annexin V-binding assays. Results CRT decreased the frequency of circulating CD4+ T cells (p<0.002) but increased that of CD4+CD39+ Treg (p≤0.001) compared to untreated or surgery-only patients. Treg frequency remained elevated for >3 years. CRT increased surface expression of LAP, GARP and CD39 on Treg. In vitro, Treg were resistant to AICD or cisplatin but conventional CD4+ T cells (Tconv) were not. CRT-induced Treg from AD or NC subjects up-regulated pro-survival proteins, while Tconv up-regulated pro-apoptotic Bax. Conclusions Highly suppressive, cisplatin-resistant Treg increase in frequency and persist after CRT and could be responsible for suppression of anti-tumor immune responses and recurrence in HNSCC.

Immunotherapy against the interaction between programmed cell death 1/programmed cell death ligand 1 (PD-L1) has emerged as a promising strategy for colorectal cancer with mismatch repair deficiency (dMMR) or microsatellite instability-high (MSI-H). The study aimed to identify miRNAs that posttranscriptionally control PD-L1 expression on tumor cells and also regulate immune evasion. A comprehensive miRNA screening using The Cancer Genome Atlas (TCGA) dataset (n ¼ 260) combined with eight different miRNA target prediction programs resulted in the identification of a tumor suppressive miRNA, miR-148a-3p, as a potential negative regulator of PD-L1 expression, particularly in dMMR/MSI-H colorectal cancer. Using multiple cohorts of colorectal cancer, including TCGA data, a microarray dataset (n ¼ 148), and formalin-fixed, paraffin-embedded samples (n ¼ 395), we found that the expression of miR-148a-3p was decreased in dMMR/MSI-H tumors, correlating inversely with PD-L1 levels. We demonstrate that miR-148a-3p directly binds to the 3 0 -untranslated region of PD-L1, thereby reducing whole-cell and cell surface PD-L1 levels in HCT116 and SW837 cell lines. Overexpression of miR-148a-3p repressed IFNg-induced PD-L1 expression on tumor cells and consequently diminished T-cell apoptosis in a coculture model of IL2-activated T cells and IFNg-treated tumor cells. In conclusion, our data support a regulatory mechanism of PD-L1 expression on tumor cells and immune suppression via miR-148a-3p downregulation in colorectal cancer. Implications:This study provides novel evidence that miR-148a-3p negatively regulates tumor cell PD-L1 expression and decreased levels of miR-148a-3p contributes to the immunosuppressive tumor microenvironment.

In this study, we successfully constructed an acceptable risk model using preoperative risk factors to predict eight postoperative morbidities highly associated with mortality in gastric cancer patients. This risk model could help to tailor perioperative management and improve clinical outcomes for patients who undergo distal gastrectomy.

Background The role of the adenosine (ADO) suppression pathway, specifically CD39-expressing and CD73-expressing CD4+ T cells in HIV-1 infection is unclear. Methods We evaluated the frequency and numbers of CD4+CD39+ and CD4+CD73+ T cells, activated T cells, and plasma C reactive protein (CRP) levels in 36 HIV-1-positive individuals and 10 normal controls (NC). Low-level plasma viremia was evaluated using single copy assay. Mass spectrometry was used to measure hydrolysis of ATP by ectoenzyme-expressing CD4+ T cells, whereas cyclic adenosine monophosphate (cAMP) levels were measured using enzyme immunoassay. Suppression of T-cell function by exogenous ADO and CD4+CD73+ T cells was tested by flow cytometry. Results CD39 and CD73 are expressed in different CD4+ T-cell subsets. CD4+CD73+ T cells do not express CD25 and FOXP3, and their frequency and numbers were lower in HIV-1-positive individuals regardless of virologic suppression (P = 0.005 and P < 0.001, respectively). CD4+CD73+ numbers inversely correlated with CD4+CD38+DR+ (P = 0.002), CD8+CD38+DR+ T-cell frequency (P = 0.05), and plasma CRP levels (P = 0.01). Both subsets are required for hydrolysis of exogenous ATP to ADO and can increase CD4+ T-cell cAMP levels when incubated with exogenous ATP. Low-level viremia did not correlate with activated T-cell frequency. In vitro, ADO suppressed T-cell activation and cytokine expression. CD4+CD73+ T cells suppressed T-cell proliferation only in the presence of exogenous 5′-AMP. Conclusion The ADO-producing CD4+CD73+ subset of T cells is depleted in HIV-1-positive individuals regardless of viral suppression and may play a key role in controlling HIV-1-associated immune activation.

Background Dendritic cells (DCs) are potent antigenpresenting cells that are central to the regulation, maturation, and maintenance of the cellular immune response against cancer. In contrast, CD4? CD25 ? regulatory T cells (Tregs) play a central role in self-tolerance and suppress antitumor immunity. In this study, we investigated the clinical significance of mature CD83? DCs and Foxp3 ?Tregs in the primary tumor and regional lymph nodes from the viewpoint of the two opposing players in the immune responses.Methods We investigated, immunohistochemically, the density of CD83 ? DCs and Foxp3 ? Tregs in primary lesions of gastric cancer (n = 123), as well as in regional lymph nodes with (n = 40) or without metastasis (n = 40). Results Decreased density of CD83? DCs and increased density of Foxp3? Tregs were observed in the primary tumor and metastatic lymph nodes. Density was significantly correlated with certain clinicopathological features. Poor prognosis was observed in patients with a low density of CD83? DCs and a high density of Foxp3 ? Tregs in primary lesions. For patients with metastatic lymph nodes, the density of CD83? DCs in negative lymph nodes was found to be an independent prognostic factor by multivariate analysis. Conclusion The density of CD83? DCs and Foxp3 ?Tregs was inversely correlated with tumor progression and reflected the prognosis of gastric cancer.

Background: The sonic hedgehog (SHH) signaling pathway is critical in fetal organogenesis. Activation of the SHH pathway has been associated with several types of human cancer; however, the clinical impact of SHH activation in patients with gastric cancer is still unknown. Methods: The present study included 41 patients with gastric cancer who underwent gastrectomy between 2000 and 2004. SHH, Patched-1 (PTCH1), Smoothened (SMO) and Glioma-associated oncogene-1 (GLI1) were examined immunohistochemically, and these of mRNAs from the cancer lesions were evaluated using real-time quantitative RT-PCR. Results: Immunohistological expressions of SHH-related molecules were relatively intense in cancer tissue, but no significant correlation was found with any clinicopathological factors of tumor. PTCH1 was only the molecule associated with poor prognosis of patients with differentiated type of tumor. For mRNA analysis, a significant correlation was demonstrated between certain clinicopathological factors and PTCH1, SMO or/and GLI1 mRNA levels. High levels of SHH and PTCH1 mRNA were associated with poor prognosis. Multivariate analysis demonstrated the PTCH1 mRNA level and liver metastasis as significant independent prognostic factors. Conclusions:PTCH1 expression in the SHH pathway was possibly involved in gastric cancer tumor progression, and could be a useful indicator for the prognosis of gastric cancer.