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目的探讨携带Survivin-△3(T34A)基因的减毒鼠伤寒沙门菌口服疫苗对乳腺瘤MCF-7注射细胞小鼠的保护作用及其效果。方法人工合成Survivin-△3(T34A)基因,先后将其克隆到真核表达载体pEGFP-N1和pVAX1载体,获得pVAX1-Survivin-△3(T34A)-EGFP真核表达载体,电转化至减毒鼠伤寒沙门菌;小鼠分别口服pVAX1-Survivin-△3(T34A)-EGFP转染沙门菌(实验组)、pVAX1-EGFP转染沙门菌(空质粒组)、沙门菌(对照组)和PBS(空白对照组)后,再皮下注射MCF-7乳腺癌细胞,采用Western-blotting检测Survivin-△3(T34A)蛋白水平,以及测定注射部位瘤块的体积大小。结果成功构建了真核表达载体pVAX1-Survivin-△3(T34A)-EGFP并转化到减毒鼠伤寒沙门菌得到表达;在空质粒组、细菌组、空白对照组和实验组小鼠中,肿瘤瘤块平均直径分别为(25.813±0.108)mm、(25.627±0.117)mm、(26.257±0.213)mm、(9.124±0.086)mm;实验组与其他组相比,差异有统计学意义(P<0.05),且能在血清中检测到Survivin-△3(T34A)-EGFP融合蛋白的存在。结论小鼠口服携带Survivin-△3(T34A)真核质粒的沙门菌后,能够抑制MCF-7乳腺瘤细胞的增殖和扩散。
Objective To investigate the protective effect of Salmonella typhimurium oral vaccine carrying Survivin-△ 3 (T34A) gene on breast cancer MCF-7-injected mice and its effect. Methods Survivin-△ 3 (T34A) gene was synthesized and cloned into eukaryotic expression vector pEGFP-N1 and pVAX1 vector to obtain eukaryotic expression vector pVAX1-Survivin-△ 3 (T34A) -EGFP. Salmonella typhimurium, Salmonella typhimurium (control group), Salmonella typhimurium (control group) and pVAX1-EGFP transfected with pVAX1-Survivin- △ 3 (T34A) (Blank control group). Then, the MCF-7 breast cancer cells were injected subcutaneously. The protein level of Survivin-△ 3 (T34A) was detected by Western-blotting, and the volume of tumor mass at the injection site was determined. Results The eukaryotic expression vector pVAX1-Survivin-△ 3 (T34A) -EGFP was successfully constructed and transformed into attenuated Salmonella typhimurium for expression. In empty plasmid group, bacteria group, blank control group and experimental mice, The average diameter of the tumor mass was (25.813 ± 0.108) mm, (25.627 ± 0.117) mm, (26.257 ± 0.213) mm and (9.124 ± 0.086) mm respectively. The difference between the experimental group and other groups was statistically significant (P < 0.05), and the presence of Survivin- △ 3 (T34A) -EGFP fusion protein could be detected in serum. Conclusion The oral administration of Salmonella typhimurium containing Survivin-△ 3 (T34A) eukaryotic plasmid can inhibit the proliferation and proliferation of MCF-7 breast cancer cells.