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目的构建表达生长抑素2型受体(SSTR2)的重组腺病毒,探讨其对裸鼠人胰腺癌移植瘤生长的影响及机制。方法2004-06-01—2005-12-10,在暨南大学生物工程学系采用位点特异性重组方法构建和包装携带人生长抑素2型受体和报告基因LacZ的重组腺病毒Ad-SSTR2和Ad-LacZ。建立裸鼠人胰腺癌移植瘤模型,分别于瘤内注射生理盐水(阴性对照组)、Ad-LacZ(报告基因对照组)和Ad-SSTR2(实验组),观察肿瘤大小和重量变化。通过逆转录-聚合酶链反应(RT-PCR)和免疫印迹试验(Western blot)鉴定SSTR2在裸鼠肿瘤组织中的表达,Western blot测定信号传导通路蛋白ERK2和ras的表达情况。结果获得滴度分别为6.0×1012pfu/L和6.5×1012pfu/L的重组腺病毒Ad-SSTR2和Ad-LacZ。Ad-SSTR2转染裸鼠胰腺癌移植瘤后SSTR2 mRNA和蛋白都得到有效表达,实验组对移植瘤生长具有明显的抑制作用,抑制率为48.2%。与阴性对照组和报告基因对照组相比,实验组ERK2和ras蛋白的表达量明显减少(P<0.01)。结论腺病毒介导的生长抑素2型受体对裸鼠人胰腺癌移植瘤的生长具有抑制作用,其作用机制可能与信号传导通路蛋白ERK2和ras的表达下调有关,提示其有可能成为胰腺癌基因治疗的一种有效方法。
Objective To construct a recombinant adenovirus expressing somatostatin type 2 receptor (SSTR2) and investigate its effect on the growth of human pancreatic cancer xenografts in nude mice and its mechanism. METHODS: From 2004-06-01 to 2005-12-10, the recombinant adenovirus Ad-SSTR2 carrying the human somatostatin type 2 receptor and the reporter gene LacZ was constructed and packaged by a site-specific recombination method at the Department of Bioengineering, Jinan University. And Ad-LacZ. A nude mouse model of human pancreatic cancer xenografts was established. Intratumoral injections of normal saline (negative control group), Ad-LacZ (reporter gene control group), and Ad-SSTR2 (experimental group) were performed to observe tumor size and weight changes. The expression of SSTR2 in tumor tissues of nude mice was identified by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Western blot was used to determine the expression of signal transduction pathway proteins ERK2 and ras. As a result, recombinant adenoviruses Ad-SSTR2 and Ad-LacZ with titers of 6.0×10 12 pfu/L and 6.5×10 12 pfu/L, respectively, were obtained. SSTR2 mRNA and protein were effectively expressed in Ad-SSTR2 transfected pancreatic cancer xenografts in nude mice. The experimental group had a significant inhibitory effect on the growth of xenografts, and the inhibition rate was 48.2%. Compared with the negative control group and the reporter gene control group, the expression levels of ERK2 and ras protein in the experimental group were significantly reduced (P<0.01). Conclusion Adenovirus-mediated somatostatin type 2 receptor inhibits the growth of human pancreatic cancer xenografts in nude mice. Its mechanism may be related to the down-regulation of ERK2 and ras signaling pathway proteins, suggesting that they may become pancreas. An effective method for cancer gene therapy.