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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。
In order to specifically express the cytosine deaminase (CD) gene in colorectal cancer cells. METHODS: A tissue-specific recombinant retroviral vector G1CEACDNa was constructed by using the cis-transcriptional regulatory sequences of CEA gene to drive the CD gene. The recombinant vector and the CD gene retroviral vector pCD2 driven by LTR were transduced by liposome method. In the colon cancer cell LoVo with high secretion of CEA, pro-drug 5-FC sensitivity test was performed after G418 was completely selected. RESULTS: LoVo cells transduced with common and tissue-specific CD genes had significantly greater inhibitory effect on 5-FC prodrugs than parental cells (all P<0.01); however, LoVo cells transduced with tissue-specific CD genes were more effective. The sensitivity of LoVo cells transduced with the common type CD gene to 5-FC was significantly higher (P<0.01), and IC50 was 0.1 mmol/L and 0.5 mmol/L, respectively. Conclusions: CEA TRS can drive suicide gene expression in high-secretion CEA colorectal cancer cells. To a certain extent, it can achieve targeted killing of tumor cells.