Lee J I, Choi D Y, Chung H S, Seo H G, Woo H J, Choi B T, Choi Y H
R&E Program, Korea Science Academy, Busan, South Korea.
Exp Oncol. 2006 Mar;28(1):30-5.
To study in vitro the molecular mechanism of apoptosis caused by beta-lapachone, a quinone obtained from the bark of the lapacho tree (Tabebuia avellanedae).
The study was carried out on human bladder carcinoma T24 cell line. Determination of cell viability was done using trypan blue exclusion method, apoptosis quantitative estimation - by DAPI staining and agarose gel electrophoresis for DNA fragmentation. Flow cytometry analysis, RT-PCR and Western blot analysis, colorimetric assay of caspase activity were applied as well.
It was found that in micromolar range of concentrations beta-lapachone inhibited the viability of T24 cells by inducing apoptosis, which could be proved by formation of apoptotic bodies and DNA fragmentation. Treatment of T24 cells with beta-lapachone resulted in a down-regulation of Bcl-2 expression and up-regulation of Bax expression. beta-lapachone-induced apoptosis was also associated with activation of caspase-3 and caspase-9, inhibition of IAP expression, and degradation of poly (ADP-ribose) polymerase, phospholipase C-gamma1 and beta-catenin proteins. At the same time Fas and FasL levels were inhibited upon treatment with beta-lapachone in a concentration-dependent manner.
beta-lapachone-induced apoptosis in T24 cells is mediated, at least in part, by the mitochondrial-signaling pathway.
在体外研究β-拉帕醌（一种从拉帕乔树（Tabebuia avellanedae）树皮中提取的醌类化合物）诱导细胞凋亡的分子机制。
本研究以人膀胱癌细胞系T24为研究对象。采用台盼蓝排斥法测定细胞活力，通过DAPI染色和DNA片段化琼脂糖凝胶电泳进行凋亡定量评估。同时应用流式细胞术分析、RT-PCR、蛋白质免疫印迹分析以及比色法检测半胱天冬酶活性。
研究发现，在微摩尔浓度范围内，β-拉帕醌通过诱导凋亡抑制T24细胞活力，凋亡小体的形成和DNA片段化可证实这一点。用β-拉帕醌处理T24细胞导致Bcl-2表达下调和Bax表达上调。β-拉帕醌诱导的凋亡还与半胱天冬酶-3和半胱天冬酶-9的激活、IAP表达的抑制以及聚（ADP-核糖）聚合酶、磷脂酶C-γ1和β-连环蛋白的降解有关。同时，用β-拉帕醌处理后，Fas和FasL水平呈浓度依赖性抑制。
β-拉帕醌诱导T24细胞凋亡至少部分是由线粒体信号通路介导的。
