Department of Physiology, University of Extremadura, Caceres, Spain.
Mol Cell Biochem. 2012 Mar;362(1-2):15-23. doi: 10.1007/s11010-011-1123-8. Epub 2011 Oct 20.
Resveratrol (3,4',5-trihydroxy-trans-stilbene), a phytoalexin naturally found in grapes and red wine, is a redox-active compound endowed with significant positive activities. In this study, the effects of resveratrol on intracellular free Ca(2+) concentration (Ca(2+)) and on cell viability in tumoral AR42J pancreatic cells are examined. The results show that resveratrol (100 μM and 1 mM) induced changes in Ca(2+), that consisted of single or short lasting spikes followed by a slow reduction toward a value close to the resting level. Lower concentrations of resveratrol (1 and 10 μM) did not show detectable effects on Ca(2+). Depletion of intracellular Ca(2+) stores by stimulation of cells with 1 nM CCK-8, 20 pM CCK-8 or 1 μM thapsigargin, blocked Ca(2+) responses evoked by resveratrol. Conversely, prior stimulation of cells with resveratrol inhibited Ca(2+) mobilization in response to a secondary application of CCK-8 or thapsigargin. In addition, resveratrol inhibited oscillations in Ca(2+) evoked by a physiological concentration of CCK-8 (20 pM). On the other hand, incubation of cells in the presence of resveratrol induced a reduction of cell viability. Finally, incubation of AR42J cells in the presence of resveratrol led to activation of c-Jun N-terminal kinase (JNK), a mitogen-activated protein kinase responsive to stress stimuli. Activation of JNK was reduced in the absence of extracellular Ca(2+). In summary, the results show that resveratrol releases Ca(2+) from intracellular stores, most probably from the endoplasmic reticulum, and reduces AR42J cells viability. Reorganization of cell's survival/death processes in the presence of resveratrol may involve Ca(2+)-mediated JNK activation.
白藜芦醇（3,4',5-三羟基反式-二苯乙烯）是一种天然存在于葡萄和红酒中的植物抗毒素，是一种具有显著积极活性的氧化还原活性化合物。在这项研究中，研究了白藜芦醇对肿瘤 AR42J 胰腺细胞内游离 Ca2+浓度(Ca2+)和细胞活力的影响。结果表明，白藜芦醇（100μM 和 1mM）诱导Ca2+发生变化，包括单个或短暂的尖峰，随后缓慢降低至接近静息水平。较低浓度的白藜芦醇（1 和 10μM）对Ca2+没有检测到可察觉的影响。通过用 1nM CCK-8、20pM CCK-8 或 1μM 他普西龙刺激细胞耗尽细胞内 Ca2+储存，阻断了白藜芦醇引起的 Ca2+反应。相反，预先用白藜芦醇刺激细胞可抑制对 CCK-8 或他普西龙的二次应用的 Ca2+动员。此外，白藜芦醇抑制了由生理浓度的 CCK-8（20pM）引起的Ca2+的振荡。另一方面，孵育细胞时加入白藜芦醇会导致细胞活力降低。最后，在存在白藜芦醇的情况下孵育 AR42J 细胞会导致 c-Jun N-末端激酶（JNK）的激活，JNK 是一种对应激刺激有反应的丝裂原激活蛋白激酶。在不存在细胞外 Ca2+的情况下，JNK 的激活减少。总之，结果表明，白藜芦醇从细胞内储存库（可能是内质网）释放 Ca2+，并降低 AR42J 细胞活力。在白藜芦醇存在的情况下，细胞存活/死亡过程的重新组织可能涉及 Ca2+介导的 JNK 激活。
