表皮生长因子介导成胶质瘤细胞NF-κB核转位的机制初探

Mechanism underlying the epidermal growth factor-mediated nuclear translocation of NF-κB in glioblastoma U-87MG cells

目的研究表皮生长因子（EGF）调节成胶质细胞瘤细胞内核因子-κB（NF-κB）核转位的可能机制。方法电泳迁移率改变分析法（EMSA）检测激活和抑制磷脂酶C-γ1（PLCγ1）后，成胶质细胞瘤U-87MG中NF-κB的核转位水平，随后采用免疫印迹法（WesternBlot）检测蛋白激酶C-α（PKCα）的表达水平，继而检测激活和抑制PKCα后NF-κB的核转位水平。结果NF-κB核转位水平在EGF刺激60min时达最大值，而经PLCγ1特异性抑制剂U-73122提前处理后，刺激后同期却无明显改变；在PKC特异性激动剂佛波酯（PMA）刺激后60minNF-κB核转位水平达高峰，而提前使用PKCα特异性抑制剂Ro 31-8220处理细胞可有效逆转此改变。结论EGF可能通过PLCγ1-PKCα信号通路介导NF-κB向核内转位，从而调控相关侵袭和转移基因的转录。

Objective To investigate the mechanisms by which nuclear factor-κB （NF-κB） translocates to nucleus of human glioblastoma U-87MG cells. Methods The levels of NF-κB translocating to nucleus in U-87MG after activation or inhibition of phospholipase C-γ1 （PLCγ 1） were first determined by electrophoretic mobility shift assay （EMSA）, and then the levels of NF-κB translocating to nucleus in U-87MG after activation or inhibition of protein kinase-α （PKCα） were determined by EMSA. Results The level ofNF-κB translocating to nucleus of U-87MG peaked 60 min after EGF stimulation, which could be reversed by the pretreatment of PLCγ1 specific inhibitor U-73122. Moreover, PKC specific agonist phorbol myristate acetate （PMA） stimulation for 60 min promoted the nuclear translocation of NF-κB to the peak, which could be also effectively reversed by the pre-treatment of PKCα specific antagonist Ro 31-8220. Conclusions Epidermal growth factor can mediate the nuclear translocation of NF-κB in U-87MG through the signal transduction of PLCγ 1-PKCα, thereby regulating the transcription of related invasion and metastasis genes.