目的：研究癌胚抗原（CEA）启动子是否能控制大肠杆菌胞嘧啶脱氨酶（EC-CD）基因在CEA阳性结肠癌细胞中专一性表达和杀伤结肠癌细胞。方法：构建由CEA启动子驱动的含EC-CD基因的重组腺病毒载体AdCEACD与由巨细胞病毒（CMV）启动子驱动的含EC-CD基因的腺病毒载体AdCMVCD，分别感染CEA阳性的人结肠癌细胞株Lovo细胞和CEA阴性的Hela细胞，用RT-PCR法检测受染细胞中EC-CD基因的表达，并用MTT法检测感染后细胞对5-氟胞嘧啶（5-FC）的敏感性。结果：Lovo细胞在AdCMVCD及AdCEACD感染后均有EC-CD mRNA表达，且对5-FC的敏感性明显增强，Hela细胞在AdCMVCD感染后有EC-CD mRNA表达，对5-FC的敏感性增强，而在AdCEACD感染后则没有EC-CD mRNA表达，5-FC对其亦无杀伤作用。结论：CEA启动子能够控制EC-CD基因专一性地在CEA阳性的结肠癌细胞中表达，从而实现EC-CD基因的靶向性作用。

Objective: To investigate whether carcino-embryonic antigen(CEA) promotor determines the specific expression of E. coli. cytotosine deaminase(EC-CD) gene and the specific cytoxicity in CEA-producing colorectal carcinoma cells. Methods:Two recombinant adenovirus vectors, AdCEACD containing EC-CD gene controlled under CEA promotor and AdCMVCD containing cytomegalovirus(CMV) promotor and EC-CD gene, were constructed. The expression of EC-CD gene in cells was tested with RT-PCR and cytotoxic effects were assayed with MTT method. Results：The CEA-producing cells (human colorectal carcinoma cell line Lovo cell) showed EC-CD mRNA expression and became sensitive to 5-fluorocytosine (5-FC) after infection with AdCEACD and AdCMVCD respectively, The CEA-nonproducing cells(Hela cell) expressed EC-CD mRNA and were sensitive to 5-FC after infection with AdCMVCD, but had no expression of EC CD mRNA and no cytotoxic effect after infection with AdCEACD. Conclusion：CEA promotor could control the expression of EC-CD gene in CEA-positive colorectal carcinoma cells specifically in vitro.

R735.35 Q782

南京医科大学创新基金资助课题（Cx9905）