肾癌细胞系SN12C 和786-O 无血清培养的干细胞球特性的比较*

目的:本研究通过比较SN12C 和786-O两株肾癌细胞系中肿瘤干细胞特征的差异性，初步探讨筛选肾癌干细胞更有效的方法。方法:以无血清培养法培养SN12C 和786-O细胞，比较其在不同时间形成肿瘤干细胞球的差异；应用流式细胞术分析SN12C 和786-O球体细胞中干细胞标志物的表达情况；利用裸鼠体内成瘤模型检测SN12C 和786-O球体细胞成瘤能力。结果:SN12C 较786-O更易形成肿瘤干细胞球且所需时间更短，即786-O在无血清培养的第7 天开始形成规则的球体，而SN12C 则在第5 天就已形成规则的球体。SN12C 和786-O球体细胞中干细胞指标表达量亦有显著性差异，在SN12C 球体细胞中CD133、CD44、Nanog和Oct3/ 4 比例明显高于786-O球体细胞，差异具有统计学意义（P < 0.05）。 裸鼠体内的成瘤能力实验发现SN12C 明显强于786-O球体细胞。结论:SN12C 肾癌细胞系通过无血清培养方法富集肿瘤干细胞球明显多于786-O，是获得肿瘤干细胞较好的研究对象。 

Characteristics of stem cell spheres of the renal carcinoma cell lines SN12C and 786-O grown in serum-free culture medium

Objective:This study aims to determine the suitable cell line to be used in isolating cancer stem cells by comparing the characteristics of tumor stem cells in renal cell carcinoma cell lines SN12C and 786-O. Methods:The rate of sphere formation in SN12C and 786-O cells was determined in serum-free medium (SFM). The expression levels of CD133, CD44, Nanog, and Oct3/4 were investi-gated through flow cytometry. Moreover, the tumorigenicity of spheroid cell that originated from SN12C and 786-O cells was investi-gated in vivo by using a tumor model. Results:The average time of sphere formation in SFM was shorter in SN12C than in 786-O (5 days vs. 7 days). Moreover, the expression levels of CD133, CD44, Nanog, and Oct3/4 in SN12C and 786-O significantly differed (P<0.05). When transplanted in nude mice, 786-O spheres were less tumorigenic than SN12C spheres. Conclusion:SN12C spheres possess the main defining characteristics of renal cancer stem cell;thus, SN12C is the more suitable cell line to be used to isolate cancer stem cells compared with 786-O.