Cao Xiaohong, Wang A H, Jiao R Z, Wang C L, Mao D Z, Yan L, Zeng B
Key Laboratory of Food Safety and Sanitation, Ministry of Education, College of food Engineering and Biotechnology, Tianjin University of Science and Technology, No. 29, 13th Avenue, Tianjin Economy Technological Development Area, Tianjin, 300457, China.
Cell Biochem Biophys. 2009;55(3):163-71. doi: 10.1007/s12013-009-9065-4. Epub 2009 Aug 11.
Surfactin, purified from Bacillus subtilis natto TK-1, inhibited proliferation of human breast cancer MCF-7 cells in a dose- and time-dependent manner, with IC(50) at 24, 48, and 72 h of 82.6, 27.3, and 14.8 microM, respectively. Surfactin-induced cell death was considered to be apoptotic by observing the typical apoptotic morphological change by acridine orange/ethidium bromide staining and Transferase-mediated dUTP Nick End-labeling assay. [Ca(2+)]i measurement revealed that surfactin induced a sustained increase in concentration of intracellular [Ca(2+)]i. Flow cytometric analysis also demonstrated that surfactin caused time-dependent apoptosis of MCF-7 cells through cell arrest at G(2)/M phase. Western blot revealed that surfactin induced accumulation of the tumor suppressor p53 and cyclin kinase inhibitor p21(waf1/cip1), and inhibited the activity of the G(2)-specific kinase, cyclin B1/p34(cdc2). Based on our findings, surfactin inhibited proliferation in MCF-7 cells by inducing apoptosis and the elevation of [Ca(2+)]i may play an important role in the apoptosis. The mechanism which surfactin caused G(2)/M arrest seems to be through cell cycle factor regulation.
从纳豆芽孢杆菌TK-1中纯化得到的表面活性素以剂量和时间依赖性方式抑制人乳腺癌MCF-7细胞的增殖，在24、48和72小时时的半数抑制浓度（IC50）分别为82.6、27.3和14.8微摩尔。通过吖啶橙/溴化乙锭染色和末端脱氧核苷酸转移酶介导的缺口末端标记测定观察到典型的凋亡形态变化，认为表面活性素诱导的细胞死亡为凋亡。细胞内钙离子浓度（[Ca(2+)]i）测量显示，表面活性素诱导细胞内[Ca(2+)]i浓度持续增加。流式细胞术分析还表明，表面活性素通过使MCF-7细胞在G(2)/M期停滞导致时间依赖性凋亡。蛋白质免疫印迹显示，表面活性素诱导肿瘤抑制因子p53和细胞周期蛋白激酶抑制剂p21(waf1/cip1)积累，并抑制G(2)特异性激酶细胞周期蛋白B1/p34(cdc2)的活性。基于我们的研究结果，表面活性素通过诱导凋亡抑制MCF-7细胞增殖，[Ca(2+)]i升高可能在凋亡中起重要作用。表面活性素导致G(2)/M期停滞的机制似乎是通过细胞周期因子调节。
