Kito Mariko, Akao Yukihiro, Ohishi Nobuko, Yagi Kunio, Nozawa Yoshinori
Institute of Applied Biochemistry, Yagi Memorial Park, Mitake, Gifu 505-0116, Japan.
Biochem Biophys Res Commun. 2002 Mar 8;291(4):861-7. doi: 10.1006/bbrc.2002.6525.
We treated four hepatocellular carcinoma cell lines, HLE, HLF, HuH7, and HepG2 with ATO and demonstrated that arsenic trioxide (ATO) at low doses (1--3 muM) induced a concentration-dependent suppression of cell growth in HLE, HLF, and HuH7. HLE cells underwent apoptosis at 2 microM ATO, which was executed by the activation of caspase-3 through the mitochondrial pathway mediated by caspase-8 activation and Bid truncation. When these cell lines were exposed to ATO in combination with l-S,R-buthionine sulfoximine (BSO) which inhibits GSH synthesis, a synergistic growth suppression was induced, even in HepG2 showing a lower sensitivity to ATO than other cell lines tested. The intracellular GSH levels after the treatment with ATO plus BSO were considerably decreased in HLE cells compared with those after the treatment with ATO or BSO alone. The production of reactive oxygen species (ROS) which was examined by 2' ,7' -dichlorodihydrofluorescein diacetate, increased significantly after the treatment with ATO plus BSO in HLE cells. These findings indicate that ATO at low concentrations induces growth inhibition and apoptosis, and furthermore that the ATO-BSO combination treatment enhances apoptosis through increased production of ROS in hepatocellular carcinoma cells.
我们用三氧化二砷（ATO）处理了四种肝癌细胞系，即HLE、HLF、HuH7和HepG2，并证明低剂量（1-3μM）的三氧化二砷（ATO）可诱导HLE、HLF和HuH7细胞生长呈浓度依赖性抑制。HLE细胞在2μM ATO作用下发生凋亡，这是通过由半胱天冬酶-8激活和Bid截短介导的线粒体途径激活半胱天冬酶-3来实现的。当这些细胞系与抑制谷胱甘肽（GSH）合成的L-S，R-丁硫氨酸亚砜胺（BSO）联合暴露于ATO时，即使在对ATO敏感性低于其他受试细胞系的HepG2中，也会诱导协同生长抑制。与单独用ATO或BSO处理后相比，HLE细胞在用ATO加BSO处理后的细胞内GSH水平显著降低。用二氯二氢荧光素二乙酸酯检测的活性氧（ROS）生成在HLE细胞用ATO加BSO处理后显著增加。这些发现表明，低浓度的ATO可诱导生长抑制和凋亡，此外，ATO-BSO联合处理通过增加肝癌细胞中ROS的生成来增强凋亡。
