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背景与目的:血管内皮生长因子(vascular endothelial growth factor,VEGF)及其主要受体血管内皮生长因子受体-2(vascular endothelial growth factor receptor-2,VEGFR-2)在肿瘤血管生成过程中起着重要作用。VEG-FR-2在鼠中为flk-1,本研究以减毒沙门氏菌SL3261为载体制备了抗肿瘤血管生成口服DNA疫苗pcDNA3.1+/flk-1(n1-7),研究该疫苗抗小鼠结肠癌肝转移的作用,并探讨其可能的作用机制。方法:RT-PCR法扩增鼠VEGFR-2胞外cDNA全长序列flk-1(n1-7),构建重组质粒pcDNA3.1+/flk-1(n1-7)。将重组质粒转化减毒沙门氏菌SL3261,制备成以SL3261为载体的口服DNA疫苗。将18只小鼠随机分组,口服接种疫苗两周后,用CT-26细胞建立结肠癌肝转移动物模型,15d后处死小鼠,体视学方法计数肝脏的肿瘤结节数目。流式细胞仪检测小鼠外周血CD4+细胞和CD8+细胞变化。结果:构建成重组质粒pcDNA3.1(+)/flk-1(n1-7),制备成以SL3261为载体的口服DNA疫苗pcD-NA3.1(+)/flk-1(n1-7)。疫苗组小鼠肝脏内的肿瘤转移病灶明显低于对照组,P<0.05。结论:成功构建了重组质粒pcDNA3.1(+)/flk-1(n1-7),制备成以SL3261为载体的口服DNA疫苗pcDNA3.1(+)/flk-1(n1-7)。这种疫苗能抑制小鼠结肠癌的肝脏转移。
BACKGROUND & OBJECTIVE: Vascular endothelial growth factor (VEGF) and its major receptor, vascular endothelial growth factor receptor-2 (VEGFR-2), play important roles in tumor angiogenesis Important role. VEG-FR-2 was flk-1 in the mouse. In this study, the anti-tumor angiogenesis oral DNA vaccine pcDNA3.1 + / flk-1 (n1-7) was prepared using attenuated Salmonella SL3261 as carrier. The role of liver metastasis in murine colon cancer and explore its possible mechanism. Methods: The full length cDNA of VEGFR-2 was amplified by RT-PCR from flk-1 (n1-7). The recombinant plasmid pcDNA3.1 + / flk-1 (n1-7) was constructed. The recombinant plasmids were transformed into attenuated Salmonella SL3261 and prepared into oral DNA vaccine with SL3261 as carrier. Twenty-eight mice were randomly divided into two groups. Two weeks after oral vaccination, CT-26 cells were used to establish animal model of liver metastasis of colon cancer. After 15 days, mice were sacrificed and the number of tumor nodules in the liver was counted by stereological method. Changes of CD4 + cells and CD8 + cells in peripheral blood of mice by flow cytometry. Results: The recombinant plasmid pcDNA3.1 (+) / flk-1 (n1-7) was constructed and used to prepare oral DNA vaccine pcD-NA3.1 (+) / flk-1 (n1-7) with SL3261 as carrier. The tumor metastasis in the liver of the vaccine group was significantly lower than that of the control group (P <0.05). CONCLUSION: The recombinant plasmid pcDNA3.1 (+) / flk-1 (n1-7) was successfully constructed and the oral DNA vaccine pcDNA3.1 (+) / flk-1 (n1-7) was prepared with SL3261 as carrier. This vaccine can inhibit the liver metastasis of colon cancer in mice.