倍半萜烯内酯对鼻咽癌细胞内核因子-κB活化的影响

Effects of Sesquiterpene Lactones on the Nuclear Factor-kappa B Activation in Human Nasopharyngeal Carcinoma Cell Line

背景与目的：探讨倍半萜烯内酯化合物对人鼻咽癌（nasopharyngeal catcinoma，NPC）细胞内核因子-κB（NF-κB）信号转导话化的影响。材料与方法：采用小白菊内酯（parthenolide，PN）作为受试物，以对PN诱导转归敏感的CNE1细胞给予TNF-α预诱导建立模型，PN处理后提取胞质和胞核蛋白，分别检测IκBα降解、NF-κB p65亚单位活化后核内迁移，电泳迁移率改变试验（EMSA）检测核内活化NF-κB的DNA结合活性。进行PN剂量和作用时间依赖关系分析。结果：阴性对照组IκBα蛋白存在于胞质中，PN处理组使TNF-α诱导的胞质IκBα蛋白降解被抑制、胞核内蛋白含量减少；相应地，阴性对照组p65亚单位在胞质中含量高于胞核内。PN处理组抑制TNF-α诱导的胞质p65核转位；同步进行的EMSA呵见，PN处理组NF-κB核结合活性比TNF-α诱导组明显降低。随PN处理时间（0．5—4h）和剂量（5～25μmol／L）增加，胞质中IκBα蛋白降解的抑制作用增强（其蛋白含量增加），胞核内p65亚单位蛋白减少，EMSA结合活性降低，呈明显的剂量和时间依赖性（P均〈0．05）。结论：PN可影响NPC细胞内NF-κB因子的活化，提示PN对TNF-α诱导NF-κB信号的抑制作用可能是PN诱导NPC细胞凋亡敏感性的分子机制之一。

BACKGROUND AND AIM： To elucidate the effect of sesquiterpene lactones on the nuclear factor-kappa B（NF-κB） signal transduction regulation in human nasopharyngeal carcinoma （NPC） cells. MATERIAIS AND METHODS： Parthenolide （PN） was used for treatment. Human CNE1 cell line was used to establish the cellular model after induction by TNF-a. The cytoplasmic and nuclear proteins were extracted after treatment by PN.the degradation of IκBα,the activation of p65 subunit and its nuclear translocation, and the DNA binding aetivity , of nunuclear activated NF-κB in EMSA assay were evaluated. RESULTS： In negative control group IκBα protein was but not in nucleus. In the PN-pretreated group, however, the IκBα protein was increased in nuclear protein. Meanwhile in PN-pretreated followed by TNF-α treatment cells, NF-κB p65 subunit level was increased in cytoplasm but was decreased in nuclei, when compared to non-PN-pretreated but TNF-α induction cells. Further EMSA analysis showed that NF-κB binding activity in PN-treated group was significantly lower than that in TNF-α-indueed group. The alterations of intracellular NF-κB signal correlated with PN-pretreatment time （0.5- 4 h） and in a dose-dependent （5- 25 /qnol/L） manner. CONCLUSION： PN inhibited the TNF-α-activated NF-κB signal transduetion pathway in NPC cells. Such inhibitory effect may be one of the molecular mechanisms associated with the sensitization of NPC to PN-indueible apoptosis.