Induction of apoptosis by shikonin through coordinative modulation of the Bcl-2 family, p27, and p53, release of cytochrome c, and sequential activation of caspases in human colorectal carcinoma cells
Induction of apoptosis by shikonin through coordinative modulation of the Bcl-2 family, p27, and p53, release of cytochrome c, and sequential activation of caspases in human colorectal carcinoma cells
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DOI：
10.1021/jf0495993
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发表时间：
2004-10-06
影响因子：
6.1
通讯作者：
Pan, MH
中科院分区：
文献类型：
--
作者：
Hsu, PC;Huang, YT;Pan, MH
紫草素是紫草根的主要成分，具有抗突变活性。然而，它的其他生物活性并不为人所知。紫草素对人结肠癌科洛205细胞和人白血病HL-60细胞显示出较强的抑制作用，IC_（50）值分别为3.12和5.5 μ M，但对人结肠癌HT-29细胞的抑制作用较弱，IC_（50）值为14.8 μ M。通过DNA片段化和亚G1 DNA峰的出现，在科洛205细胞中证实了诱导凋亡，其之前是线粒体膜电位的丧失、活性氧（ROS）的产生、细胞色素c的释放以及随后的caspase-9和-3加工的诱导。在科洛205细胞中，紫草素可诱导聚ADP核糖聚合酶（PARP）和DNA片段化因子（DFF-45）的裂解，并激活caspase-9和caspase-3。在此，我们发现紫草素诱导的凋亡细胞死亡伴随着p27、p53和Bad的上调以及Bcl-2和Bcl-X-L的下调，而紫草素对Bax蛋白的水平几乎没有影响。综上所述，我们认为紫草素诱导的细胞凋亡是由细胞色素c释放到胞质溶胶中、半胱天冬酶-9加工、半胱天冬酶-3活化、PARP降解以及半胱天冬酶活化的脱氧核糖核酸酶通过消化DFF-45引起的DNA片段化引发的。紫草素诱导细胞凋亡可能是其化学预防肿瘤的重要机制之一。
Shikonin is a main constituent of the roots of Lithospermum erythrorhizon that has antimutagenic activity. However, its other biological activities are not well-known. Shikonin displayed a strong inhibitory effect against human colorectal carcinoma COLO 205 cells and human leukemia HL-60 cells, with estimated IC50 values of 3.12 and 5.5 muM, respectively, but were less effective against human colorectal carcinoma HT-29 cells, with an estimated IC50 value of 14.8 muM. Induce apoptosis was confirmed in COLO 205 cells by DNA fragmentation and the appearance of a sub-G1 DNA peak, which were preceded by loss of mitochondrial membrane potential, reactive oxygen species (ROS) generation, cytochrome c release, and subsequent induction of pro-caspase-9 and -3 processing. Cleavages of poly(ADP-ribose) polymerase (PARP) and DNA fragmentation factor (DFF-45) were accompanied by activation of caspase-9 and -3 triggered by shikonin in COLO 205 cells. Here, we found that shikonin-induced apoptotic cell death was accompanied by upregulation of p27, p53, and Bad and down-regulation of Bcl-2 and Bcl-X-L, while shikonin had little effect on the levels of Bax protein. Taken together, we suggested that shikonin-induced apoptosis is triggered by the release of cytochrome c into cytosol, procaspase-9 processing, activation of caspase-3, degradation of PARP, and DNA fragmentation caused by the caspase-activated deoxyribonuclease through the digestion of DFF-45. The induction of apoptosis by shikonin may provide a pivotal mechanism for its cancer chemopreventive action.