Pan M H, Lin J H, Lin-Shiau S Y, Lin J K
Institute of Biochemistry, College of Medicine, National Taiwan University, Taipei.
Eur J Pharmacol. 1999 Sep 24;381(2-3):171-83. doi: 10.1016/s0014-2999(99)00549-x.
Penta-O-galloyl-beta-D-glucose is structurally related to (-)-epigallocatechin gallate and is isolated from hydrolyzed tannin. Penta-O-galloyl-beta-D-glucose can inhibit tumor promotion by teleocidin. We investigated the effects of penta-O-galloyl-beta-D-glucose and various tea polyphenols on cell viability in human leukemia HL-60 cells. In this study, we demonstrated that penta-O-galloyl-beta-D-glucose was able to induce apoptosis in a concentration- and time-dependent manner; however, other polyphenols were less effective. We further investigated the molecular mechanisms of penta-O-galloyl-beta-D-glucose-induced apoptosis. Treatment with penta-O-galloyl-beta-D-glucose caused induction of caspase-3/CPP32 activity in dose- and time-dependent manner, but not caspase-1 activity, and induced the degradation of poly-(ADP-ribose) polymerase. Pretreatment with acetyl-Asp-Glu-Val-Asp-aldehyde (Ac-DEVD-CHO) and Z-Val-Ala-Asp-fluoromethyl-ketone (Z-VAD-FMK) inhibited penta-O-galloyl-beta-D-glucose-induced DNA fragmentation. Furthermore, treatment with penta-O-galloyl-beta-D-glucose (50 microM) caused a rapid loss of mitochondrial transmembrane potential, release of mitochondrial cytochrome c into cytosol, and subsequent induction of procaspase-9 processing. Our results indicate that penta-O-galloyl-beta-D-glucose allows caspase-activated deoxyribonuclease to enter the nucleus and degrade chromosomal DNA, and induces DFF-45 (DNA fragmentation factor) degradation. These results lead to a working hypothesis that penta-O-galloyl-beta-D-glucose-induced apoptosis is triggered by the release of cytochrome c into the cytosol, procaspase-9 processing, activation of caspase-3, degradation of poly-(ADP-ribose) polymerase, and DNA fragmentation caused by the caspase-activated deoxyribonuclease through the digestion of DFF-45. The induction of apoptosis by penta-O-galloyl-beta-D-glucose may provide a pivotal mechanism for its cancer chemopreventive action.
五-O-没食子酰基-β-D-葡萄糖在结构上与（-）-表没食子儿茶素没食子酸酯相关，且是从水解单宁中分离得到的。五-O-没食子酰基-β-D-葡萄糖可抑制远藤菌素的肿瘤促进作用。我们研究了五-O-没食子酰基-β-D-葡萄糖和各种茶多酚对人白血病HL-60细胞活力的影响。在本研究中，我们证明五-O-没食子酰基-β-D-葡萄糖能够以浓度和时间依赖性方式诱导细胞凋亡；然而，其他多酚的效果较差。我们进一步研究了五-O-没食子酰基-β-D-葡萄糖诱导细胞凋亡的分子机制。用五-O-没食子酰基-β-D-葡萄糖处理以剂量和时间依赖性方式诱导了半胱天冬酶-3/CPP32活性，但未诱导半胱天冬酶-1活性，并诱导了聚（ADP-核糖）聚合酶的降解。用乙酰-Asp-Glu-Val-Asp-醛（Ac-DEVD-CHO）和Z-Val-Ala-Asp-氟甲基酮（Z-VAD-FMK）预处理可抑制五-O-没食子酰基-β-D-葡萄糖诱导的DNA片段化。此外，用五-O-没食子酰基-β-D-葡萄糖（50微摩尔）处理导致线粒体跨膜电位迅速丧失，线粒体细胞色素c释放到细胞质中，并随后诱导前半胱天冬酶-9的加工。我们的结果表明，五-O-没食子酰基-β-D-葡萄糖使半胱天冬酶激活的脱氧核糖核酸酶进入细胞核并降解染色体DNA，并诱导DFF-45（DNA片段化因子）降解。这些结果得出一个工作假设，即五-O-没食子酰基-β-D-葡萄糖诱导的细胞凋亡是由细胞色素c释放到细胞质中、前半胱天冬酶-9的加工、半胱天冬酶-3的激活、聚（ADP-核糖）聚合酶的降解以及半胱天冬酶激活的脱氧核糖核酸酶通过消化DFF-45导致的DNA片段化所触发的。五-O-没食子酰基-β-D-葡萄糖诱导的细胞凋亡可能为其癌症化学预防作用提供一个关键机制。
