HT29和HCT116结肠癌细胞无血清培养形成肿瘤干细胞球特性的差异性研究

目的比较HT29和HCT116两种结肠癌细胞系中肿瘤干细胞的差异，初步探讨结肠癌干细胞研究模型。方法以无血清培养法培养HT29和HCT116细胞，观察其在不同时间形成肿瘤干细胞球的差异，用限制性稀释法计算两者的成球率；流式细胞术分析HT29和HCT116细胞系中CD44／CD24的表达情况；裸鼠体内成瘤实验鉴定HT29细胞球与HCT116细胞球成瘤能力。结果无血清培养法发现HCT116较HT29更易形成肿瘤干细胞球且所需时间更短，即HT29在无血清培养的第7天开始形成规则的球体，而HCT116则在第5天就已形成规则的球体，HCT116成球率（11．4±1．15）％高于HT29（3．31±0．27）％，且差异有统计学意义（P〈0．05）；HT29和HCT116中CD44±／CD24±各细胞含量有显著差异，结果显示具有干细胞特性的CD44＋／CD24＋结肠癌细胞在HCT116中所占比例（60．33±5．75）％明显高于HT29（9．23±2．15）％，差异有统计学意义（t=13．939，P〈0．05）；体内成瘤实验发现HCT116细胞球在裸鼠体内的成瘤能力明显强于HT29细胞球，HCT116细胞球的成瘤速度及瘤体生长速度都较HT29细胞球快。结论与HT29相比，HCT116结肠癌细胞系更适合作为肿瘤干细胞研究的模型。

The difference of tumor stem cell spheres of HT29 and HCT116 colon cancer cells in serum free floating-culture system

Objective To investigate the difference of tumor stem cells in HT29 and HCT116 cell lines and evaluate the model of colon cancer stem cell research.Methods HT29 and HCT116 cells were cultured in serum-free medium(SFM) to develop spheres.The growth states of spheres in two cell lines were observed and the rate of spheres’ formation was obtained by limiting dilution analysis.The expression of CD44±/CD24± cells were detected by flow cytometry.The tumorigenicity of spheres originated from HT29 and HCT116 was investigated in vivo by tumorigenicity assays.Results The average time of spheres’ formation generated from HCT116 was shorter than HT29((5 days vs 7 days) in SFM,the rate of spheres derived from HCT116 was significantly higher than HT29 (11.4±1.15)% vs(3.31±0.27)%].There was significant difference in the expression of CD44±/ CD24± between HT29 and HCT116.The expression of CD44+/CD24-were(9.23±2.15)% and(60.33±5.75)% in HT29 and HCT116,separately(t=13.939,P<0.05).HT29 spheres were less tumorigenic compared with HCT116 spheres when transplanted in nude mice.Conclusion HCT116 is more appropriate for colon cancer stem cell research than HT29.