| Background and Objective:Pancreatic carcinoma is one of the deadliest malignancies. The pathogenesis of pancreatic carcinoma is concealed; the early diagnosis is difficult; the effect of clinical therapy is very poor; and the 5-year survival rate less than 1%. Most people could not receive radical surgery when the doctor found lesions, and the conventional chemotherapy and radiotherapy could not significantly improve the survival rate and the quality of patient’s life. Therefore, the immunotherapy has become a hot research topic in today’s treatment of pancreatic carcinoma. However, the existence of the tumor microenvironment could largely affect the effect of the immunotherapy.Dendritic cells (DCs) as the most classic antigen presenting cells (APCs) play very important effect in the immune system. But because of the existence of the tumor microenvironment, the immunologic function of DCs inhibited in the patients with cancer, so that they could not play the effective immune response. The experimental results of in vivo and vitro show that the differentiation and maturation of DCs were inhibited, whether the DCs taken from patients with pancreatic carcinoma or cultured in the supernatants of pancreatic carcinoma cells. Now therefore, the interaction mechanism between tumor microenvironment and pancreatic carcinoma cells (PCCs) has drawn much attention and been the hot topic.We all know that the regulatory T cells (Treg cells) play a crucial role in the tumor microenvironment. The forkhead/winged helix transcription factor FOXP3 is highly expressed in Treg cells, and has been identified as a key player in regulating their inhibiting effect. In recent years, many studies show that the FOXP3 could also expressed in pancreatic carcinoma cells, and this phenomenon can regulate the function of the tumor microenvironment. This article aims to investigate the influence of FOXP3 expression in pancreatic carcinoma cells on the maturation and immunologic function of DCs.Methods:The siRNA sequences targeting FOXP3 gene were specifically designed and transfected to PCCs, the level of IL-10 and TGF-β1 of culture supernatant were detected by ELISA. The supernatants of pancreatic carcinoma cells, the supernatants of pancreatic carcinoma cells transfected by FOXP3 siRNA and the supernatants of pancreatic carcinoma cells transfected by FOXP3 negative siRNA were collected, mixed with GM-CSF and IL-4 to induce the differentiation of DCs, loaded with tumor antigen and stimulated by Bacille Calmette-Guerin (BCG). Flow cytometric and FACS analysis were used to measure the expression of surface markers on DCs which were deal with supernatants. The levels of IL-12p70, IFN-y were detected by ELISA. The DCs co-cultured with T lymphocytes, the lymphocytes proliferation and cytotoxicity were analyzed by CCK-8 assays.Results:Specific down-regulation of FOXP3 in PCCs could down-regulate the secretion of IL-10 and TGF-β1 (P<0.05). The DCs were cultured in the medium containing the supernatants of the pancreatic carcinoma cell transfected by FOXP3 siRNA could strengthen the expression of surface markers (CD86 and HLA-DR, P <0.05) and the secretion of IL-12p70 (P<0.05) and IFN-γ (P<0.05) compared with the group of Negative control. However, there was no significantly difference in the expression CD80 (P> 0.05) between each other. The DCs were cultured in the supernatants of the pancreatic carcinoma cell transfected by FOXP3 siRNA co-cultured with T lymphocytes could significantly increase the proliferation of T lymphocytes (P<0.05) and the ability of CTL to kill pancreatic carcinoma cells (P <0.05).Conclusion:FOXP3 expression in PCCs can inhibit the maturation and immunologic function of DCs. |
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