Department of Pharmacology, China Medical University, Taichung, Taiwan, R.O.C.
In Vivo. 2012 Nov-Dec;26(6):971-8.
Chlorogenic acid exists widely in edible and medicinal plants and acts as an antioxidant. It is known to exert antitumor activity via induction of apoptosis in many human cancer cells. However, its signaling pathway in human leukemia cells still remains unclear. Therefore, we investigated the roles of reactive oxygen species (ROS), mitochondria and caspases during chlorogenic acid-induced apoptosis of U937 human leukemia cells. Chlorogenic acid exhibited a strong cytotoxicity and induced apoptosis in U937 cells, as determined by 4,6-diamidino-2-phenylindole dihydrochloride (DAPI) staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Chlorogenic acid induced apoptosis by promoting ROS production and reduced the mitochondrial membrane potential (ΔΨm), as assayed by flow cytometry. Furthermore, the activity of caspase-3 was evaluated and results indicated that chlorogenic acid promoted caspase-3 activity in U937 cells. Results from western blot analysis showed that chlorogenic acid promoted expression of caspase-3, -7, -8 and -9 in U937 cells. Taken together, these results suggest that chlorogenic acid may induce apoptosis by reducing the levels of ΔΨm and by increasing the activation of caspase-3 pathways in human leukemia U937 cells in vitro.
绿原酸广泛存在于食用和药用植物中，具有抗氧化作用。已知它通过诱导许多人类癌细胞凋亡来发挥抗肿瘤活性。然而，其在人类白血病细胞中的信号通路仍不清楚。因此，我们研究了活性氧（ROS）、线粒体和半胱天冬酶在绿原酸诱导 U937 人白血病细胞凋亡中的作用。通过 4,6-二脒基-2-苯基吲哚二盐酸盐（DAPI）染色和末端脱氧核苷酸转移酶 dUTP 缺口末端标记（TUNEL）检测，绿原酸对 U937 细胞表现出强烈的细胞毒性并诱导其凋亡。绿原酸通过促进 ROS 产生和降低线粒体膜电位（ΔΨm）来诱导细胞凋亡，这通过流式细胞术进行了测定。此外，还评估了半胱天冬酶-3 的活性，结果表明绿原酸促进了 U937 细胞中 caspase-3 的活性。Western blot 分析结果表明，绿原酸促进了 U937 细胞中 caspase-3、-7、-8 和 -9 的表达。综上所述，这些结果表明，绿原酸可能通过降低ΔΨm 水平并增加人白血病 U937 细胞中 caspase-3 途径的激活来诱导细胞凋亡。
