Pan Min-Hsiung, Chang Yen-Hui, Badmaev Vladimir, Nagabhushanam Kalyanam, Ho Chi-Tang
Department of Seafood Science, National Kaohsiung Marine University, Kaohsiung 811, Taiwan.
J Agric Food Chem. 2007 Sep 19;55(19):7777-85. doi: 10.1021/jf071520h. Epub 2007 Aug 16.
Pterostilbene, an active constituent of blueberries, is known to possess anti-inflammatory activity and also induces apoptosis in various types of cancer cells. Here, the effects of pterostilbene on cell viability in human gastric carcinoma AGS cells were investigated. This study demonstrated that pterostilbene was able to inhibit cell proliferation and induce apoptosis in a concentration- and time-dependent manner. Pterostilbene-induced cell death was characterized with changes in nuclear morphology, DNA fragmentation, and cell morphology. The molecular mechanism of pterostilbene-induced apoptosis was also investigated. The results show the caspase-2, -3, -8, and -9 are all activated by pterostilbene, together with cleavage of the downstream caspase-3 target DNA fragmentation factor (DFF-45) and poly(ADP-riobse) polymerase. Moreover, the results indicate that the Bcl-family of proteins, the mitochondrial pathway, and activation of the caspase cascade are responsible for pterostilbene-induced apoptosis. Pterostilbene markedly enhanced the expression of growth arrest DNA damage-inducible gene 45 and 153 (GADD45 and GADD153) in a time-dependent manner. Flow cytometric analysis indicated that pterostilbene blocked cell cycle progression at G1 phase in a dose- and time-dependent manner. Pterostilbene increased the p53, p21, p27, and p16 proteins and decreased levels of cyclin A, cyclin E, cyclin-dependent kinase 2 (Cdk2), Cdk4, and Cdk6, but the expression of cyclin D1 was not affected. Over a 24 h exposure to pterostilbene, the degree of phosphorylation of Rb was decreased after 6 h. In summary, pterostilbene induced apoptosis in AGS cells through activating the caspase cascade via the mitochondrial and Fas/FasL pathway, GADD expression, and by modifying cell cycle progress and changes in several cycle-regulating proteins. The induction of apoptosis by pterostilbene may provide a pivotal mechanism of the antitumor effects and for treatment of human gastric cancer.
紫檀芪是蓝莓的一种活性成分，已知具有抗炎活性，还能诱导多种癌细胞凋亡。在此，研究了紫檀芪对人胃癌AGS细胞活力的影响。本研究表明，紫檀芪能够以浓度和时间依赖性方式抑制细胞增殖并诱导凋亡。紫檀芪诱导的细胞死亡表现为核形态、DNA片段化和细胞形态的变化。还研究了紫檀芪诱导凋亡的分子机制。结果显示，caspase-2、-3、-8和-9均被紫檀芪激活，同时下游caspase-3靶标DNA片段化因子（DFF-45）和聚（ADP-核糖）聚合酶发生裂解。此外，结果表明Bcl蛋白家族、线粒体途径和caspase级联反应的激活是紫檀芪诱导凋亡的原因。紫檀芪以时间依赖性方式显著增强生长停滞DNA损伤诱导基因45和153（GADD45和GADD153）的表达。流式细胞术分析表明，紫檀芪以剂量和时间依赖性方式将细胞周期进程阻滞在G1期。紫檀芪增加了p53、p21、p27和p16蛋白的表达，降低了细胞周期蛋白A、细胞周期蛋白E、细胞周期蛋白依赖性激酶2（Cdk2）、Cdk4和Cdk6的水平，但细胞周期蛋白D1的表达未受影响。在24小时暴露于紫檀芪的过程中，6小时后Rb的磷酸化程度降低。总之，紫檀芪通过线粒体和Fas/FasL途径激活caspase级联反应、GADD表达以及改变细胞周期进程和几种周期调节蛋白，诱导AGS细胞凋亡。紫檀芪诱导凋亡可能为其抗肿瘤作用和治疗人类胃癌提供关键机制。
