Ji Li-Li, Chen Ying, Wang Zheng-Tao
Key Laboratory of Standardization of Chinese Medicines of Ministry of Education, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Road, Shanghai, PR China.
Exp Toxicol Pathol. 2008 Jun;60(1):87-93. doi: 10.1016/j.etp.2007.11.010. Epub 2008 Jan 30.
Clivorine is an otonecine-type pyrrolizidine alkaloid (PA) isolated from the Chinese medicinal plant Ligularia hodgsonii Hook., and our previous reports have shown its toxicity on human normal liver L-02 cells. It is generally believed that biotransformation of PAs to its metabolites is required for their toxicity; thus, there is nearly no report about the toxicity of clivorine on other non-hepatic cells in vitro. The aim of this study is to observe the toxicity of clivorine on the non-hepatic human embryonic kidney 293 (HEK293) cell that is of epithelial origin, and its primary mechanism. Our results showed that clivorine significantly reduced HEK293 cell viability, but there was no detectable apoptotic DNA ladder and cleaved fragments of caspase-3 and caspase-9 in clivorine-treated cells, which indicates the toxicity of clivorine is not due to inducing apoptosis. The results of western blot showed that clivorine induced sustained p38, c-Jun N-terminal kinase (JNK) and extracellular signal-related kinases (ERK1/2) phosphorylation in a concentration- and time-dependent manner, and the JNK inhibitor SP600125 significantly augmented the toxicity of clivorine. Our results suggest that clivorine itself has direct toxicity on HEK293 cells, and phosphorylated JNK may play some role in counteracting the toxicity of clivorine on HEK293 cells.
千里光裂碱是一种从中国药用植物霍氏橐吾中分离出的耳草碱型吡咯里西啶生物碱（PA），我们之前的报道已表明其对人正常肝L-02细胞具有毒性。一般认为，PA转化为其代谢产物是其产生毒性所必需的；因此，几乎没有关于千里光裂碱对其他非肝细胞体外毒性的报道。本研究的目的是观察千里光裂碱对上皮来源的非肝人胚肾293（HEK293）细胞的毒性及其主要机制。我们的结果表明，千里光裂碱显著降低了HEK293细胞的活力，但在经千里光裂碱处理的细胞中未检测到凋亡DNA梯形条带以及半胱天冬酶-3和半胱天冬酶-9的裂解片段，这表明千里光裂碱的毒性并非由诱导凋亡所致。蛋白质印迹结果显示，千里光裂碱以浓度和时间依赖性方式诱导p38、c-Jun氨基末端激酶（JNK）和细胞外信号调节激酶（ERK1/2）持续磷酸化，并且JNK抑制剂SP600125显著增强了千里光裂碱的毒性。我们的结果表明，千里光裂碱本身对HEK293细胞具有直接毒性，并且磷酸化的JNK可能在对抗千里光裂碱对HEK293细胞的毒性中发挥一定作用。
