胞嘧啶脱氨酶基因体外特异性前药转换抗大肠癌作用研究

Human Colorectal Carcinoma Tissue-specific Anti-tumor Gene Therapy by Using Cytosine Deaminase Gene in vitro

为使胞嘧啶脱氨酶(CD)基因在大肠癌细胞中特异表达。方法:构建了以CEA基因顺式转录调控序列驱动CD基因的组织特异型重组逆转录病毒载体G1CEACDNa,以脂质体法将重组载体及转录受LTR驱动的CD基因逆转录病毒载体pCD2分别转导入高分泌CEA的大肠癌细胞LoVo中,经G418完全选择后进行前药5-FC敏感试验。结果:转导普通型及组织特异型CD基因的LoVo细胞较亲代细胞对5-FC的前药转换抑瘤效应明显(均为P<0.01);而转导组织特异性CD基因的LoVo细胞较转导普通型CD基因的LoVo细胞对5-FC的敏感性显著增高(P<0.01),其IC_(50)分别为0.1mmol/L和0.5mmol/L。结论:表明CEA TRS可驱动自杀基因在高分泌CEA大肠癌细胞中特异性表达,在一定程度上达到了靶向杀伤肿瘤细胞的目的。

Aims:To make cytosine deaminase gene specifically expressed in colorectal carcinoma calls. Methods: Recombinant retroviral vector G1CEACDNa, in which CEA promoter from the plasmid pCEA424/2CAT was employed to promote CD gene, was constructed. The retroviral construct and pCD 2, a retroviral; vector contained CD gene under control of viral long terminal repeats, were introduced into high CEA producing colorectal carcinoma cell line LoVo. After full selected in G418, the proliferated colonies were treated with prodrug 5-fluorocytocine(5-FC). Results: It was demonstrated that, both of them were more sensitive to 5-FC than their parental cells. Furthermore, The LoVo cells transfered with G1CEACDNa gene display a higher anti-tumor effect than the cells transfered with pCD2 in vitro. Conclusions: The CEA/CD chimeric gene should be a potential tool for tumor-specific colorectal carcinoma gene therapy.