中文摘要：

目的：探讨MCF-7、MDA-MB-231及原代乳腺癌细胞微球体形成的影响因素,并检测其中CD44^＋/CD24^-/low的表达。方法：将MCF-7、MDA-MB-231及原代乳腺癌细胞进行微球体培养。取培养第7天的微球体细胞,用流式细胞术分析干细胞比例。结果：MCF-7形成微球体的效率最高（2.1%±0.3%）,MDA-MB-231很少能形成微球体,原代乳腺癌细胞中未观察到微球体形成。但在无B27的干细胞培养环境中,MCF-7易贴壁生长。MCF-7单层培养细胞中CD44^＋/CD24^-/low的比例为2.0%±0.1%,将悬浮及贴壁来源的MCF-7细胞进行微球体培养,微球体细胞中CD44^＋/CD24^-/low的比例分别为11.8%±0.3%和8.2%±0.8%（P〈0.01）。MDA-MB-231及原代乳腺癌细胞中CD44^＋/CD24^-/low的表达比例分别为92.2%±3.1%和93.8%±2.4%。结论：MCF-7细胞通过微球体培养富集了肿瘤干细胞,而MDA-MB-231及原代乳腺癌细胞则不能。MDA-MB-231及原代乳腺癌细胞中CD44＋/CD24-/low的表达与微球体形成不呈正相关。

英文摘要：

Objective： To investigate the influential factors on the formation of mammospheres from MCF-7, MDA-MB-231 and primary breast cancer epithelial cells, and to detect the proportion of CD44^＋/CD24^-/low among them. Methods： MCF-γ, MDA-MB-231 and primary breast cancer epithelial cells were cultured in suspension to generate primary mammospheres. After 7 days of cultivation, the proportion of cancer stem cells was measured in cells derived from mammosphere cells or monolayer culture cells by flow cytometry. Results： MCF-7 had the highest efficiency of mammosphere formation （2. 1%±0. 3% ）, while MDA-MB-231 cells hardly had any mammosphere formation, and no mammosphere formation was observed in breast cancer epithelial cells. MCF-7 tended to adhere under stem cell culture conditions without B27. Flow cytometry analysis indicated that, compared with 2.0% ＋ 0. 1% for the MCF-7 monolayer culture ceils, 11.8%±0.3% and 8.2%±0. 8% of the MCF-7 mammosphere cells from MCF-7 under different conditions were CD44^＋＋/CD24^-/low （P〈0.01）. The proportion of CD44^＋/ CD24^-/low expression in MDA-MB-231 cells and primary breast cancer epithelial ceils was 92.2%±3.1% and 93.8%±2.4%, respectively. Conclusion： Compared with monolayer culture ceils, MCF-7 mammosphere cells contained higher proportion of breast cancer stem cells, while MDA-MB-231 and primary breast cancer epithelial cells did not. The expression of CD44^＋/CD24^-/low in MDA-MB-231 and primary breast cancer epithelial cells did not correlate with mammosphere formation positively.