不同乳腺癌干细胞亚群的自我更新和致瘤能力差异

目的 分析原代培养乳腺癌细胞中不同乳腺癌干细胞亚群的自我更新、致瘤能力差异。方法 采用流式细胞术和免疫荧光实验，从乳腺癌原代培养细胞中分选、鉴定CD44⁺CD24^-/low、ALDH1⁺和ALDH1⁺CD44⁺CD24^-/low细胞亚群，分析各分选细胞占总肿瘤细胞的比例；通过克隆形成实验观察各组细胞的自我更新能力；通过裸鼠致瘤实验观察各组细胞的致瘤能力。结果 CD44+CD24^-/low细胞占总细胞比例的7.2%，ALDH1⁺细胞所占比例为4.6%，ALDH1⁺CD44⁺CD24^-/low细胞所占比例为1.5%。三组细胞自我更新和致瘤能力由强至弱依次为ALDH1⁺CD44⁺CD24^-/low、ALDH1⁺、CD44⁺CD24^-/low细胞，各组细胞间比较差异均存在统计学意义（P<0.05）。 结论 乳腺癌组织中CD44+CD24-/low、ALDH1⁺和ALDH1⁺CD44⁺CD24^-/low三组乳腺癌干细胞亚群之间的自我更新和致瘤能力有明显差异，ALDH1⁺CD44⁺CD24^-/low亚群细胞具有最强的自我更新和致瘤能力，提示ALDH1⁺CD44⁺CD24^-/low可能是更具有特异性的乳腺癌干细胞标志物。

Difference of Self-renewal and Tumorigenicity among Different Breast Cancer Stem Cells Subpopulations

Objective To analyze the difference of self-renewal and tumorigenicity among different breast cancer stem cells subpopulations. Methods CD44⁺CD24-/low, ALDH1⁺ and ALDH1⁺CD44⁺CD24-/low cells populations were isolated from fresh breast cancer tissues by flow cytometry analysis and the percentage of each isolated cells in total tumor cells were calculated. By clone formation and immunofluorescence experiments, the capacities of self-renew of each subpopulation cells were analyzed. We utilized the mouse model to observe the tumorigenicity of the three different subgroups. Results The subpopulations of CD44⁺CD24^-/low, ALDH1⁺and ALDH1⁺CD44⁺CD24^-/low accounted for 7.2%, 4.6% and 1.5% of total tumor cells respectively. ALDH1⁺CD44⁺CD24^-/low subpopulation had the strongest capacity of self-renewal and tumorigenicity, while CD44⁺CD24^-/low phenotype breast cancer cells were proved to be the weakest (P<0.05). Conclusion ALDH1⁺CD44⁺CD24^-/low subpopulation have the strongest capacity of self-renewal and tumorigenicity than CD44⁺CD24^-/low and ALDH1⁺, which suggests that ALDH1⁺CD44⁺CD24^-/low could be a more specific marker of breast cancer stem cells.