目的：探讨呼肠孤病毒对乳腺癌微球体细胞凋亡的影响。方法：以干细胞培养液培养乳腺癌细胞MCF-7和BT474,形成微球体，分别用呼肠孤病毒和表柔比星处理微球体，FCM检测MCF-7、BT474微球体细胞中CD44+CD24-/low细胞的比例，TUNEL法检测微球体细胞的凋亡，Western blotting检测MCF-7细胞及其微球体细胞中Ras的表达。结果：呼肠孤病毒对乳腺癌MCF-7和BT474微球体细胞的感染率显著高于亲本细胞（均P<0.05）。表柔比星作用下MCF-7和BT474微球体细胞中CD44+CD24-/low细胞比例明显升高\[（8.1±0.4）% vs（18.0±4.5）%，P<0.01；（0.6±0.2）% vs（0.9±0.13）%，P<0.05\]。呼肠孤病毒感染后MCF-7和BT474微球体细胞中CD44+CD24-/low细胞比例明显下降\[（8.1±0.4）% vs（0.8±02）%，（0.6±0.2）% vs（0.2±0.1）%；均P<0.05\]。MCF-7和BT474微球体细胞在呼肠孤病毒感染后凋亡率明显增加\[（1.90±0.21）% vs（5.0±1.4）%，P<0.05；（0.20±0.1）% vs（1.0±0.16）%，P<0.05\]。MCF-7细胞及其微球体细胞均高表达Ras，且两者水平相似。结论：与表柔比星相比，呼肠弧病毒对乳腺癌微球体细胞的抑制作用明显，还可明显诱导乳腺癌微球体细胞凋亡。

Objective:To investigate the effect of reovirus on apoptosis of breast cancer mammosphere cells. Methods:MCF-7 and BT474 cells were cultured in stem cell culture medium to generate mammospheres. Then the mammospheres were infected by reovirus or treated with epirubicin, The proportion CD44+CD24-/low cells in the mammosphere cells from MCF-7 and BT474 cells was detected by flow cytometry (FCM); the apoptosis of mammosphere cells was detected by TUNEL; and the expression of Ras in MCF-7 cells and the mammosphere cells was examined by Western blotting. Results: The infection rates of reovirus on MCF-7 and BT474 mammosphere cells were significantly higher than those on MCF-7 and BT474 cells (all P<0.05). The proportions of CD44+CD24-/low cells in the mammosphere cells from MCF-7 and BT474 cells after treatment with epirubicin were improved greatly (\[8.1±0.4\]% vs \[18.0±4.5\]%, P<0.01; \[0.6±0.2\]% vs \[0.9±0.13\]%, P<0.05), while the proportions of CD44+CD24-/low cells in the mammosphere cells after treatment with reovirus were decreased apparently (\[8.1±0.4\]% vs \[0.8±0.2\]%, P<0.05; \[0.6±0.2\]% vs \[0.2±0.1\]%, P<0.05). The apoptosis rates of the mammospheres cells from MCF-7 and BT474 cells rose up from (1.9±0.21)% to (5±1.4)% (P<0.05) and from (0.2±0.1)% to (1.0±0.16)% (P<0.05) after reovirus treatment. Ras levels in MCF-7 cells and the mammosphere cells were almost same high. Conclusion: Compared with that of epirubicin, reovirus has a higher inhibitory effect on breast cancer mammosphere cells, while reovirus distinctively induces apoptosis of mammosphere cells.