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[目的]探讨RNA干扰沉默DcR3对人胰腺癌细胞裸鼠移植瘤放疗敏感性的影响及其可能机制。[方法]取对数生长期的AsPC-1细胞1×10~7/ml,接种于6周龄裸鼠左后肢腹股沟,当皮下肿瘤直径为8mm左右时,随机分为4组(n=15):PBS组、DcR3siRNA组、放疗组(RT)和DcR3siRNA+放疗组(DcR3siRNA+RT),观察DcR3siRNA联合放疗对人胰腺癌AsPC-1细胞裸鼠移植瘤的治疗效果;应用ELISA和Western blot检测各组DcR3的蛋白表达变化;免疫组织化学和Western blot分析各组Caspase-8和Caspase-3蛋白表达的变化;TUNEL检测各组肿瘤细胞凋亡情况。[结果]DcR3siRNA+RT组较其他各组更能抑制移植瘤的生长,DcR3-siRNA+RT对肿瘤的抑制率明显高于单纯RT组,与RT组相比,DcR3siRNA+RT组的抑瘤率为80.86%±4.17%;DcR3siRNA+RT组的DcR3蛋白量和蛋白相对表达均明显低于RT组,差异有统计学意义(P<0.05);DcR3siRNA+RT组的Caspase-8和Caspase-3蛋白表达均明显高于单独RT组;DcR3siRNA组、RT组以及DcR3-siRNA+RT组肿瘤组织内均可观察到凋亡细胞,而DcR3siRNA+RT组肿瘤细胞凋亡数目明显高于RT组或DcR3siRNA组。[结论]RNA干扰沉默DcR3基因可以增加人胰腺癌细胞裸鼠移植瘤对放疗的敏感性,该作用可能与沉默DcR3可激活Caspase-8/Caspase-3凋亡途径和促进肿瘤细胞凋亡有关。
[Objective] To investigate the effect of RNAi silencing DcR3 on radiosensitivity of human pancreatic cancer xenografts in nude mice and its possible mechanism. [Method] AsPC-1 cells in logarithmic growth phase were inoculated into the inguinal region of left hind limb of 6-week-old nude mice when the subcutaneous tumor size was about 8mm, and were randomly divided into 4 groups (n = 15 (DcR3siRNA + RT) and DcR3siRNA + RT were used to observe the therapeutic effect of DcR3siRNA and radiotherapy on human pancreatic adenocarcinoma xenografts in nude mice. ELISA and Western blot The expression of DcR3 protein was detected by immunohistochemistry and Western blot. The changes of Caspase-8 and Caspase-3 protein expression in each group were detected by immunohistochemistry and TUNEL. [Results] The DcR3siRNA + RT group was more able to inhibit the growth of xenografts compared with other groups. The inhibition rate of DcR3-siRNA + RT was significantly higher than that of pure RT group. Compared with RT group, the inhibition rate of DcR3siRNA + RT group (80.86% ± 4.17%). The expression of DcR3 protein and protein in DcR3siRNA + RT group was significantly lower than that in RT group (P <0.05). The expressions of Caspase-8 and Caspase-3 in DcR3siRNA + The expression of apoptotic cells in DcR3siRNA group, DcR3siRNA group and DcR3-siRNA + RT group was higher than that in RT alone group. The number of apoptotic cells in DcR3siRNA + RT group was significantly higher than that in RT group or DcR3siRNA group . [Conclusion] Silencing DcR3 gene by RNAi can increase the sensitivity of human pancreatic cancer xenografts to radiotherapy, which may be related to the activation of Caspase-8 / Caspase-3 apoptotic pathway and the promotion of tumor cell apoptosis by DcR3 silencing.