Silencing invariant chains of dendritic cells enhances anti-tumor immunity using small-interfering RNA

• Published in: Chinese medical journal Vol. 123; no. 22; pp. 3193 - 3199
• Main Authors: Ke, Shan, Chen, Xue-Hua, Zhu, Zheng-Gang, Li, Jian-Fang, Yu, Bei-Qin, Gu, Qin-Long, Liu, Bing-Ya
• Format: Journal Article
• Language: English
• Published: China Department of Hepatobiliary Surgery,West Campus,Bejing Chaoyang Hospital,Capital Medical University,Beijing 100043,China%Department of Surgery,Shanghai Institute of Digestive Surgery,Ruijin Hospital,School of Medicine,Shanghai Jiao Tong University,Shanghai 200025,China 20.11.2010
• Subjects: Animals; Antigens, Differentiation, B-Lymphocyte - genetics; Antigens, Differentiation, B-Lymphocyte - metabolism; Blotting, Western; Cells, Cultured; Dendritic Cells - immunology; Dendritic Cells - metabolism; Female; Flow Cytometry; Gene Silencing - physiology; Histocompatibility Antigens Class II - genetics; Histocompatibility Antigens Class II - metabolism; Mice; Neoplasms - immunology; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference - physiology; RNA, Small Interfering - genetics; RNA, Small Interfering - physiology; RNA干扰; siRNA; 体外抗肿瘤; 小干扰RNA; 树突状细胞; 流式细胞仪分析; 肿瘤免疫; 转录后基因沉默; tumor immunity; dendritic cells; small-interfering RNA; invariant chain
• ISSN: 0366-6999; 2542-5641
• DOI: 10.3760/cma.j.issn.0366-6999.2010.22.004

Background Genetic modification of dendritic cells （DCs） has been used as an effective approach to enhance anti-tumor immunity. RNA interference （RNAi）, which can cause the degradation of any RNA in a sequence-specific manner, is a post-transcriptional gene silencing mechanism. In this study, small-interfering RNA （siRNA） specific for the li gene was transfected into DCs, and the anti-tumor immunity of li-silenced DCs was assessed. Methods The silencing effect of siRNA was evaluated by Western blotting and real-time PCR analyses. In vitro cytotoxic activity of T cells was evaluated using a Cytotox 96 non-radioactive cytotoxicity assay kit. The time to tumor onset and the tumor volumes were used as reliable indices to assess the anti-tumor immunity in vivo. To further examine the mechanisms underlying the anti-tumor immunity, flow cytometry analysis was used. Results The li expression of DCs was significantly reduced after li siRNA transfection. Significant in vitro anti-tumor ability was exhibited when DCs were co-transfected with li siRNA plus endogenous tumor antigen （P 〈0.05）. Furthermore tumor growth was greatly inhibited when mice were immunized with DCs transfected with li siRNA plus tumor antigen prior to or subsequent to tumor implantation. Flow cytometry analysis in vitro and in vivo indicated that both CD4^= and CD8^＋ T cells were significantly activated in the li siRNA group （P 〈0.05）. Conclusion Silencing of the li gene of DCs may offer a potential approach to enhance DC-based anti-tumor immunity.