CD基因表达诱导结肠癌细胞的凋亡作用

Induction of apoptosis in colon cancer cells by CD gene expression

目的:研究胞嘧啶脱氨酶(cytosinedeaminase,CD)基因表达是否具有诱导结肠癌细胞凋亡的作用。方法:用不同浓度的5氟胞嘧啶(5flurocytosine,5FC)加至CD基因阳性人结肠癌细胞株SW1116培养,MTT法检测5FC药物对结肠癌细胞生长抑制作用。AnnexinV/PI法分析细胞凋亡率,用透射电镜观察细胞结构改变。结果:与未导入基因的SW1116细胞相比,CD基因阳性细胞对5FC的敏感性明显增加,50%细胞生长抑制率(IC50)浓度由SW1116细胞的16000μmol/L降低到SWCD2的66μmol/L。CD基因导入细胞能够增加5FC诱导的细胞凋亡率。SW1116细胞凋亡率:未加药为2.52%,加药24h为4.61%,48h为2.25%,72h为8.41%;而SWCD2的凋亡率:未加药为4.81%,加药后24h为4.73%,48h为20.78%,72h为32.92%,细胞凋亡率的增加与给药时间成正比。电镜下可见明显的凋亡细胞形态特征。结论:CD基因表达对人结肠癌细胞生长的抑制作用涉及肿瘤细胞凋亡机制。

OBJECTIVE： To investigate the induction of apoptosis in colon cancer cells by CD gene expression. METHODS： Colon cancer cell line SW1116 transfected with CD gene was cultured with 5-FC. The cytotoxicity of 5-FC was assayed with MTT, the apoptosis rates was measured by Annextin V/PI labeling through FCM and the structure of cell was observed by electron microscopy. RESULTS： The transgene cells SWCD2 increased the sensitivity to the nontoxic prodrug 5-FC, decreasing the IC50 for 5-FC from 16 000 μmol/L for parental SW1116 cell to 66 μmol/L for SWCD2 cell. The apoptosis rates of SWCD2 was 4. 81% in control cells, 4.73% exposured to 5-FC after 24 h, 20. 78% after 48 h and 32.92% after 72 h. The increase of apoptosis rate was dependent on the time exposured to 5-FC. The characteristic of apoptosis was observed in SWCD2 cells after exposured to 5-FC. CONCLUSION： The growth inhibition of colon cancer cell is involved in apoptosis mechanism by CD gene expression.