Department of Clinical and Molecular Medicine, Piazza Sassari 3, La Sapienza University, 00161 Rome, Italy.
Br J Nutr. 2013 Sep 14;110(5):797-809. doi: 10.1017/S0007114512006095. Epub 2013 Feb 25.
Grape seed extract (GSE) from Italia, Palieri and Red Globe cultivars inhibits cell growth and induces apoptosis in Caco-2 human colon cancer cells in a dose-dependent manner. In order to investigate the mechanism(s) supporting the apoptotic process, we analysed reactive oxygen species (ROS) production, intracellular Ca2+ handling and extracellular signal-regulated kinase (ERK) activation. Upon exposure to GSE, ROS and intracellular Ca2+ levels increased in Caco-2 cells, concomitantly with ERK inactivation. As ERK activity is thought to be essential for promoting survival pathways, inhibition of this kinase is likely to play a relevant role in GSE-mediated anticancer effects. Indeed, pretreatment with N-acetyl cysteine, a ROS scavenger, reversed GSE-induced apoptosis, and promoted ERK phosphorylation. This effect was strengthened by ethylene glycol tetraacetic acid-mediated inhibition of extracellular Ca2+ influx. ROS and Ca2+ influx inhibition, in turn, increased ERK phosphorylation, and hence almost entirely suppressed GSE-mediated apoptosis. These data suggested that GSE triggers a previously unrecognised ERK-based mechanism, involving both ROS production and intracellular Ca2+ increase, eventually leading to apoptosis in cancer cells.
意大利、帕莱里和红地球品种的葡萄籽提取物（GSE）以剂量依赖的方式抑制 Caco-2 人结肠癌细胞的生长并诱导其凋亡。为了研究支持凋亡过程的机制，我们分析了活性氧（ROS）的产生、细胞内 Ca2+的处理和细胞外信号调节激酶（ERK）的激活。暴露于 GSE 后，Caco-2 细胞中的 ROS 和细胞内 Ca2+水平增加，同时 ERK 失活。由于 ERK 活性被认为对于促进存活途径是必需的，因此抑制这种激酶可能在 GSE 介导的抗癌作用中发挥相关作用。事实上，用 N-乙酰半胱氨酸（一种 ROS 清除剂）预处理可逆转 GSE 诱导的细胞凋亡，并促进 ERK 磷酸化。这种作用通过乙二醇四乙酸介导的细胞外 Ca2+流入抑制得到加强。ROS 和 Ca2+流入的抑制反过来又增加了 ERK 的磷酸化，从而几乎完全抑制了 GSE 介导的细胞凋亡。这些数据表明，GSE 触发了一种以前未被识别的基于 ERK 的机制，涉及 ROS 的产生和细胞内 Ca2+的增加，最终导致癌细胞凋亡。
