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.