Yamasaki Masao, Miyamoto Yumi, Chujo Hitomi, Nishiyama Kazuo, Tachibana Hirofumi, Yamada Koji
Division of Food Science and Nutrition, Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, Miyazaki University, Miyazaki 889-2192, Japan.
Biochim Biophys Acta. 2005 Aug 15;1735(3):176-84. doi: 10.1016/j.bbalip.2005.05.010.
Conjugated linoleic acid (CLA) is a powerful anti-carcinogenic fatty acid. Previously, we showed that 10trans 12cis (10t, 12c) CLA induced apoptotic cell death in rat hepatoma. Here, we demonstrated significant cytotoxic effects of 1 muM 10t, 12c-CLA, but not 9c, 11t-CLA, on dRLh-84 rat hepatoma cells. 9t, 11t and 9c, 11c-CLA also showed low levels of cytotoxic activity. 10t, 12c-CLA activated caspase-3, 9 followed by cytochrome c release from mitochondria into the cytosol. Inhibitors of caspase-3, 9 blocked the cytotoxicity of 10t, 12c-CLA. 10t, 12c-CLA also induced translocation of Bax protein into the mitochondrial membrane and cleavage of Bid protein. Lysosomal destabilization induced by 10t, 12c-CLA was observed by monitoring the re-localization of Acridine Orange and the leakage of beta-hexosaminidase from lysosomes. 10t, 12c-CLA directly degraded the isolated lysosomes from the rat liver. Our observations indicate that 10t, 12c-CLA induces mitochondria-related apoptosis accompanied by lysosomal destabilization in rat hepatoma cells.
共轭亚油酸（CLA）是一种强大的抗癌脂肪酸。此前，我们发现10反式12顺式（10t，12c）CLA可诱导大鼠肝癌细胞发生凋亡性细胞死亡。在此，我们证明了1μM 10t，12c-CLA对dRLh-84大鼠肝癌细胞具有显著的细胞毒性作用，但9顺式11反式（9c，11t）CLA则没有。9反式11反式（9t，11t）和9顺式11顺式（9c，11c）CLA也显示出较低水平的细胞毒性活性。10t，12c-CLA激活了半胱天冬酶-3，随后细胞色素c从线粒体释放到细胞质中。半胱天冬酶-3的抑制剂可阻断10t，12c-CLA的细胞毒性。10t，12c-CLA还诱导了Bax蛋白向线粒体膜的转位以及Bid蛋白的裂解。通过监测吖啶橙的重新定位和β-己糖胺酶从溶酶体的泄漏，观察到10t，12c-CLA诱导的溶酶体不稳定。10t，12c-CLA直接降解了从大鼠肝脏分离的溶酶体。我们的观察结果表明，10t，12c-CLA在大鼠肝癌细胞中诱导与线粒体相关的凋亡，并伴有溶酶体不稳定。
