The Expression Of Decoy Receptor 3(DcR3) In Human Pancreatic Carcinoma And Its Effect On T Lymphocyte In Vitro

PartⅠ Clinical significance and expression of Dc R3 in humanpancreatic carcinomaObjective To study the expression and significance of Dc R3 in human pancreatic carcinoma.Methods(1) Immunohistochemistry(IHC) and enzyme linked immunosorbent assay(ELISA) were performed to detect the expression of Dc R3 in 40 pairs of pancreatic tumor tissues and in their serum. Then the relationship between Dc R3 expression and clinical pathological factors was analyzed.(2) Flow cytometry(FCM) was performed to detect the expression of CD4+、CD8+ T cell in patients blood of 40 patients with pancreatic cancerResults(1) The positive rate of Dc R3 expression in pancreatic tumor tissues was 62.5%, while the positive rate was 12.5% in adjacent nontumorous tissues.Dc R3 was overexpressed in tumor tissues compared with nontumous tissues(χ2=21.33,P<0.001). And the expression of Dc R3 is closely related to the tumor stages and lymph node metastasis, the difference was statistically significant(P < 0.05).(2) The expression of Dc R3 levels in serum in patients with pancreatic carcinoma were increased significantly, compared with pancreatic benign tumor and the healthy group, differences were statistically significant(P < 0.01).(3)In pancreatic carcinoma-patients, CD4/CD8 in the peripheral blood negatively related with the levels of Dc R3(Spearman, r = 0.6512, P < 0.0001).Conclusions The expression of Dc R3 proteins in pancreatic carcinoma were correlated with tumor stages and lymph node metastasis. The expression of Dc R3 in serum was negative correlation with CD4 /CD8 in the peripheral blood, and Dc R3 was one of the factors that affect the human immune function.PartⅡ Effect on T lymphocyte function by Silencing Dc R3 onhuman pancreatic carcinoma cells in vitroObjective To investigate the effect on T lymphocyte function by silencing decoy receptor 3(Dc R3) in human Pancreatic cancer cell line Panc-1.Methods Small interfering RNA(si RNA) expression vector targeting Dc R3 gene was infected into Panc-1 cells by Lentiviral-mediated RNAi. After the co-culture the T lymphocyte and the infected tumor cells, lymphocyte subsets were examined by flow cytometry analysis and the levels of IFN-γ, IL-4 were determined by ELISA. Flow cytometry by CD3- detection of tumor cells in the mixed culture cell apoptosis rate was detected by Annexin V- FITC/PI assays, and proliferation of T lymphocyte was examined by CFDA-SE.Results(1) In the Dc R3-si RNA group, the expression of Dc R3 was decreased in Panc-1 cells remarkably.(2) After silencing Dc R3 in tumor cells, the number of CD3+, CD4+T lymphocyte in co-culture was increased(P<0.05) and the number of CD8+T lymphocyte was unchanged statistically. The number of Th1 cells was increased, while the number of Th2 cells was decreased(P<0.05). In cell supernatant, the level of IFN-γ was increased, while the level of IL-4 was decreased.(3) The expression of CD25 and CD69 on T cells increased, proliferation rate of T lymphocyte increased in the Dc R3-RNAi group. And tumor cell apoptosis rate has increased significantly, the differences were statistically significant(P < 0.05).Conclusion Silencing Dc R3 may regulate the function of T lymphocyte and correct the imbalance of Th1/Th2. Dc R3 is expected to become the potential target of gene therapy in pancreatic carcinoma.