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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 whether cytosine deaminase (CD) gene expression can induce the apoptosis of colon cancer cells. Methods: Different concentrations of 5flurocytosine (5FC) were added to the CD gene-positive human colon cancer cell line SW1116 and the inhibitory effects of 5FC on the growth of colon cancer cells were detected by MTT assay. The apoptosis rate was analyzed by Annexin V / PI method. The cell structure was observed by transmission electron microscope. Results: The sensitivity of CD gene positive cells to 5FC was significantly higher than that of SW1116 cells without any gene transfer. The IC50 of 50% was decreased from 16000μmol / L to 66μmol / L SWCD2. The introduction of CD gene into cells increased the 5FC-induced apoptosis rate. The apoptotic rates of SW1116 cells were 2.52% for dosing, 4.61% for dosing for 24 h, 2.25% for 48 h and 8.41% for 72 h, while the apoptotic rate of SWCD16 was 4.81% for dosing and 4.73 h after dosing %, 48h 20.78%, 72h 32.92%, the increase of apoptosis rate is proportional to the administration time. Under electron microscope, obvious morphological features of apoptotic cells were observed. Conclusion: The inhibitory effect of CD gene expression on the growth of human colon cancer cells involves the mechanism of tumor cell apoptosis.