MCF-7异质性及肿瘤干细胞相关亚群初步研究

Heterogeneity of MCF-7 and study on cancer stem cell related subpopulation in it

目的:探讨人乳腺癌细胞系MCF-7的异质性及其肿瘤干细胞相关亚群(SP细胞或CD44+CD24-/low细胞)的性质。方法:采用Percoll不连续密度梯度法分离MCF-7,流式细胞仪检测各亚群中SP和CD44+CD24-/low细胞比例及各亚群细胞周期时相分布,各亚群细胞体外培养获得其生长曲线,平板克隆实验检测各亚群的增殖能力。结果:经Percoll分选MCF-7可形成A、B、C、D和E 5个亚群。各亚群中SP细胞比例分别为1.43%、2.15%、6.43%、25.23%和2.09%,其中D亚群中SP细胞富集。细胞周期时相分布显示,D亚群中G0/G1静止期细胞比例最高(P<0.05),为80.58%。生长曲线显示D亚群生长速度最快,以下依次为A亚群、B亚群、C亚群和E亚群。各亚群克隆形成率分别为(32.5±3.7)%、(41.3±4.8)%、(50.8±4.3)%和(68.2±3.5)%,其中D亚群具有最高的克隆形成率(P<0.05),而E亚群未形成明显的克隆性集落。但各亚群中均未检测到明显的CD44+CD24-/low细胞。结论:乳腺癌细胞系MCF-7具有异质性特征,经Percoll分选MCF-7可形成5个异质性的亚群,其中D亚群富含肿瘤干细胞相关亚群(SP细胞),但MCF-7在长期体外培养过程中,乳腺癌干细胞表面标志CD44+CD24-/low可能已经改变。

OBJECTIVE： To investigate the heterogeneity of human breast cancer cell line MCF-7 and the characteristic of cancer stem cell related subpopulation（SP cells or CD44＋ CD24-/Wcells） in it. METHODS： MCF-7 was separated by Percoll gradient centrifugation. SP cells, CD44＋ CD24-,,w cells and cell cycle phase distribution of each subpopulation were detected with flow cytometry. The growth curve was obtained by each subpopulation cultured in vitro. The reproduc tive activity of each subpopulation was tested by flat cloning experiment. RESULTS： After separated by Percoll gradient centrifugation,MCF 7 formed A, B,C,D and E subpopulations. The percentage of SP cells in each subpopulation was 1.43% ,2.15% ,6.43% ,25.23% and 2.09% respectively. Subpopulation D was rich in SP cells. The percentage of G0/Gquiescent stage cells in subpopulation D was the highest （P〈0.05）,up to 80.58 %. The growth curve showed that sub- population D grewing was the fastest and the following sequence was subpopulation A,subpopulation B,subpopulation C and subpopulation E. The colony formation rate of each subpopulation was （32. 5 ± 0. 7） %, （41. 3 ± 4. 8） %, （ 50. 8 ± 4.3 ）and （68.2 ± 3.5）M. Subpopulation D had the highest colony formation rate（P〈0.05 ）. Subpopulation E didn＇t formed conspicuous clonal colony. There was almost no CD44＋ CD24-jlW cells detected in each subpopulation. CONCLU- SIONS： Human breast cancer cell line MCF-7 is heterogeneous. After separated by Percoll gradient centrifugation, MCF-7 forms five heterogeneous subpopulations. Subpopulation D is rich in cancer stem cell related subpopulation（SP cells）. With long time cuhure in vitro,breast cancer stem cell surlace marker CD44＋ CD24 in MCF-7 may have changed.