SAPK/JNK信号通路在鼻咽癌放疗群集耐受中的作用研究

Role of SAPK/JNK signaling pathway in multicellular resistance to radiotherapy for human nasopharyngeal carcinoma

目的用CNE-2Z多细胞球(multicellular spheroids,MCSs)模拟实体瘤,探讨SAPK/JNK信号通路在鼻咽癌放疗群集耐受中的作用。方法采用liquid overlay技术进行MCSs培养,Western blot法检测X射线照射后信号通路活性变化,SAPK/JNK信号通路特异阻断剂sp-600125作用前后Caspase-3蛋白表达变化;TUNEL法检测sp-600125作用前后、X射线照射后MCSs凋亡率变化。结果X射线照射后MCSs中SAPK/JNK信号通路表现动态磷酸化过程,其中2h磷酸化水平最高;预先阻断信号通路X射线照射后,细胞凋亡率上调(P<0.05),caspase-3蛋白表达增高(P<0.05)。结论SAPK/JNK信号通路短暂激活可能传递生存信号而在鼻咽癌放疗群集耐受中发挥作用,特异性阻断其信号传递上调MCSs凋亡率,这可能与促进caspase-3蛋白表达有关。

Objective Taking CNE-2Z muhicellular spheroids （MCSs） as the simulation of solid tumors, to investigate the role of SAPK/JNK signaling pathway in muhicellular resistance to radiotherapy for human nasopharyngeal carcinoma （NPC）. Methods Human NPC cell line CNE-2Z were cultured into muhicellular spheroids by using liquid overlay technique, then divided into control MCSs, irradiated MCSs （average dose in one minute： 2 Gy） , sp-600125（ a specific inhibitor for SAPK/JNK signaling pathway） ＋ irradiated MCSs, sp600125 ＋ MCSs. Western blotting was employed to analyze the activity of SAPK/JNK signaling pathway in MCSs, and the expression of Caspase-3 protein before and after sp-600125 treatment; X-ray induced cell apoptotisis in MCSs before and after sp-600125 treatment was detected by TUNEL. Results The level of SAPK/JNK phosphorylation in MCSs was a dynamic course after radiation, and the phosphorylation peaked at 2 h after irradiation ; The apoptotic rate of MCSs （ P 〈 0.05 ） and the expression of Caspase-3 protein （ P 〈 0.05） were significantly increased after sp-600125 treatment. Conclusion The transient activation of SAPK/JNK plays an important role in muhicellular resistance to radiotherapy for human NPC via mediating survival signals, block this pathway so as to accelerate cell apoptosis. The increased apoptosis of MCSs by blocking SAPK/JNK signaling pathway may be related to the increased expression of Caspase-3.