腺病毒载体介导的胞嘧啶脱氨酶和胸苷激酶融合基因体外抑瘤效果的观察

In vitro antitumor effect of CD, TK fusion suicide gene induced by adenovirus vector

目的构建重组腺病毒载体,观察自杀基因对不同大肠癌细胞系的细胞毒作用。方法利用重组腺病毒载体介导的胞嘧啶脱氨酶(CD)、单纯疱疹病毒胸苷激酶(HSV-tk)融合基因感染人结肠腺癌细胞系LoVo、HCT-8和直肠腺癌细胞系HR-8348,通过细胞集落形成实验、细胞存活率测定(MTT法),检测和分析HSV-tk/丙氧鸟苷((GCV)、CD/5-氟胞嘧啶(5-FC)双自杀基因系统对肿瘤细胞的杀伤作用和旁观者效应的大小。结果 Western Blot检测分析融合基因的表达,显示重组腺病毒介导的双自杀基因可以在3种肿瘤细胞中表达。不加5-FC和GCV时,各转染组和对照组肿瘤细胞集落形成分别为:94、93、95;96、92、94,比较差异无显著性(P>0.05)。在5-FC(80.0mg/L)和GCV(0.8 mg/L)浓度下3种肿瘤细胞存活率降至2.1％、4.3％和3.2％,与不用前药相比差异有显著性(P<0.01)。感染细胞在混合细胞中比例仅仅占5％时,就能获得明显的旁观者效应,细胞杀伤率分别升至22.2％、34.8％和40.4％。结论CD、TK融合基因联合联合双前药治疗能取得显著的抗肿瘤作用。

Objective To construct a recombinant adenovirus and observe the antitumor effect of the double suicide gene therapy to three different colorectal cancer cell lines. Methods Cytosine deami-nase (CD) and herpes simplex virus thymidine kinase (HSV-tk) fusion gene were transfected into LoVo colon cancer cells, HCT-8 colon cancer cells and HR-834813 rectal cancer cells via an adenovirous vector. Clony forming test and MTT method were used to evaluate the antitumor effect of HSV-tk/GCV (ganci-clovir) system and CD/5-FC(5-fluorocytosine) system against tumor cells. The bystander effect was also observed. Results Western blot analysis demonstrated the fusion protein could be effectively expressed in these three kinds of transfected tumor cells. The plating efficiency of transfection groups and control group was 94, 93, 95 and 96, 92, 94 in the absence of 5-FC and GCV, respectively. There was no statistical significance between them, P >0.05. In the presence of 5-FC(80 mg/L)and GCV(0. 8 mg/L), the survival rate of tumor cells was reduced to 2.1 % , 4. 3 % and 3.2%, significantly different from that before administration ( P < 0.01) . Strong bystander effect could be obtained when the proportion of transfected cells in the mixing group was 5 % and the cell killing ratio was increased to 22.2 % , 34.8 % and 40.4 % respectively. Conclusion Significant antitumor effects could be obtained with the combined use of CD, TK fusion gene and double prodrugs.