Jow Guey-Mei, Chou Cheng-Jen, Chen Bing-Fang, Tsai Jia-Huei
School of Medicine, Fu Jen Catholic University, 510, Chung-Cheng Road, Hsin-Chuang, Taipei Hsien 242, Taiwan.
Cancer Lett. 2004 Dec 28;216(2):165-73. doi: 10.1016/j.canlet.2004.06.005.
Beauvericin (BEA), a cyclic hexadepsipeptide, induces cell death in human leukemia cells (CCRF-CEM) and the process of BEA-induced cell death has been speculated to undergo an apoptotic pathway. In the present study, several well-characterized factors, known to play important roles in apoptotic pathway, were investigated in BEA-induced CCRF-CEM cell death. CCRF-CEM cells were treated with BEA at concentrations from 1 to 10 microM for up to 24 h. The incidence of nuclear fragmentation and apoptotic body formation in the cells, cytosolic caspase-3 activity, mitochondrial membrane potential, and release of cytochrome c (Cyt c) from mitochondria in BEA-treated cells were determined and compared with that in untreated cells. Moreover, to investigate the role of intracellular Ca++ in this cell death process, CCRF-CEM cells were primed with 3 microM of BAPTA/AM, a Ca++ chelator, to exclude intracellular Ca++ prior to the BEA treatment. The data revealed that BEA-induced cell death in CCRF-CEM cells exhibited a dose- and time-dependent manner. The incidence of nuclear fragmentation and apoptotic body formation was significantly increased in CCRF-CEM cells treated with BEA at concentrations of 1 microM or greater. Increase of cytosolic caspase-3 activity was also observed in BEA-treated cells with a dose-dependent manner. In addition, increased release of Cyt c from mitochondria was also observed in the cells treated with 10 microM BEA in a time-dependent pattern. The BAPTA/AM pretreatment partially blocked BEA-induced cell death in CCRF-CEM cells, indicating that intracellular Ca++ plays an important role, maybe as a mediator in cell death signaling, in this cell death pathway. The results support the notion that BEA-induced cell death in CCRF-CEM cells likely undergo through an apoptotic pathway on the basis of increase of release of Cyt c from mitochondria, increase of caspase-3 activity, and some observed typical apoptotic cellular changes in morphology.
白僵菌素（BEA）是一种环状六肽缩酯，可诱导人白血病细胞（CCRF-CEM）死亡，并且推测BEA诱导细胞死亡的过程是通过凋亡途径进行的。在本研究中，对几种已知在凋亡途径中起重要作用且特征明确的因子进行了研究，以探讨其在BEA诱导的CCRF-CEM细胞死亡中的作用。用浓度为1至10微摩尔的BEA处理CCRF-CEM细胞长达24小时。测定了BEA处理的细胞中细胞核碎片化和凋亡小体形成的发生率、胞质半胱天冬酶-3活性、线粒体膜电位以及细胞色素c（Cyt c）从线粒体的释放情况，并与未处理细胞进行了比较。此外，为了研究细胞内Ca++在该细胞死亡过程中的作用，在BEA处理之前，先用3微摩尔的BAPTA/AM（一种Ca++螯合剂）预处理CCRF-CEM细胞，以排除细胞内Ca++。数据显示，BEA诱导的CCRF-CEM细胞死亡呈现剂量和时间依赖性。在浓度为1微摩尔或更高的BEA处理的CCRF-CEM细胞中，细胞核碎片化和凋亡小体形成的发生率显著增加。在BEA处理的细胞中也观察到胞质半胱天冬酶-3活性呈剂量依赖性增加。此外，在用10微摩尔BEA处理的细胞中，还观察到Cyt c从线粒体的释放呈时间依赖性增加。BAPTA/AM预处理部分阻断了BEA诱导的CCRF-CEM细胞死亡，表明细胞内Ca++在该细胞死亡途径中起重要作用，可能作为细胞死亡信号传导的介质。这些结果支持了这样一种观点，即基于Cyt c从线粒体释放的增加、半胱天冬酶-3活性的增加以及一些观察到的典型凋亡细胞形态变化，BEA诱导的CCRF-CEM细胞死亡可能通过凋亡途径进行。
