目的：探讨下调CDl33 基因的表达对肝癌细胞生物学行为的影响。方法：将合成的CDl33 小干扰核糖核酸分子（siRNA）转染至肝癌SMMC7721 细胞并检测转染效率；分别以无转染与转染随机siRNA 序列的SMMC7721 细胞为空白对照和阴性对照，观察CDl33 siRNA 转染后CDl33 基因沉默效果，以及SMMC7721 细胞主要生物学行为的变化。结果：转染24 h 后，转染效率可达到（80.8±9.1）%；与空白对照组比较，CDl33 siRNA 转染后的SMMC7721 细胞CD133 mRNA 及蛋白表达量分别降至空白对照组的10% 与35%、细胞增殖活性明显降低、细胞凋亡率明显增加（41.3% vs. 25.3%）并出现明显的S 期阻滞，集落形成能力明显降低（均P<0.05）。阴性对照组与空白对照组各指标无统计学差异（均P>0.05）。结论：CDl33 在肝癌细胞中可能起了癌基因作用，下调其表达能抑制肝癌的恶性生物学行为。
Impact of CDl33 expression down-regulation on malignant biological behaviors of liver cancer cells
Objective: To investigate the influence of downregulating CDl33 gene expression on biological behaviors of human liver cancer cells. Methods: Liver cancer SMMC7721 cells were transfected with the synthesized CDl33 siRNA and then transfection efficiency was determined. Using SMMC7721 cells without transfection or transfected with scrambled siRNA sequence as blank control and negative control respectively, the effect of CD133 gene silencing, and changes in the main biological behaviors in SMMC7721 cells after CDl33 siRNA transfection were observed. Results: The transfection efficiency reached (80.8±9.1) % at 24 h after transfection. Compared with blank control group, in SMMC7721 cells after CDl33 siRNA transfection, the expression level of CDl33 mRNA and protein was reduced to 10% and 35% of the level in blank control group respectively, the proliferative activity was significantly decreased, apoptosis rate was significantly increased with a marked S-phase arrest, and colony-forming ability was significantly decreased (all P<0.05). All indexes did not show any significant difference between negative control group and blank control group (all P>0.05). Conclusion: CDl33 gene may play an oncogene role in liver cancer cells and down-regulating its expression can suppress the malignant activity of liver cancer.