靶向抑制EGFR核转位对鼻咽癌细胞辐射耐受相关分子DNA-PK活化的作用

Inhibition of Targeting Nuclear Translocation of EGFR on Expression of DNA-PK Activation associated with Radioresistance in Nasopharyngeal Carcinoma Cells

目的:探讨EGFR核转位抑制肽对鼻咽癌细胞辐射耐受相关分子DNA-PK表达的作用及其潜在的分子关联机制。方法:采用EGFR核转位抑制肽(pT654)及对照肽(5μM)预处理人鼻咽癌CNE-1细胞16h,细胞再暴露于60Coγ射线,辐射4Gy后采用Western blot方法分别测定细胞质和细胞核EGFR和pEGFRThr654,以及非同源末端连接(NHEJ)修复作用相关的DNA-PK和p DNA-PKThr2609在不同时间点的表达,分析pEGFRThr654与p DNAPKThr2609表达的相互关联。结果:辐射后CNE-1细胞的核EGFR和pEGFRThr654表达呈时间依赖性的增加,且与pDNA-PKThr2609的表达呈正相关(R^2=0.935);EGFR核转位抑制肽p T654显著降低核pEGFRThr654和pDNA-PKThr2609的表达(R^2=0.962)。结论:EGFR核转位抑制肽可阻遏辐射诱导的鼻咽癌细胞EGFR核转位及其介导的NHEJ修复通路相关分子DNA-PK的活化。

Objective： To investigate the effect of EGFR nuclear translocation inhibitory peptide on the expression of radioresistance related nuclear DNA-PK in nasopharyngeal carcinoma cells and its potential molecular mechanism. Methods： CNE-1 cells were pretreated with EGFR nuclear translocation inhibitory peptide（ p T654） and control peptide（ 5 μM） for 16 h,then the cells were exposed to 4Gy60 Co irradiation. Western blot was used to determine the expression of EGFR,pEGFRThr654,DNA-PK and p DNA-PKThr2609 in cytoplasm and cell nucleus of CNE-1 cells at different time points,and the relationship between pDNA-PKThr2609 and p EGFRThr654 was also investigated. Results： The expression of EGFR and p EGFRThr654 in CNE-1 cells increased significantly after the radiation,and the expression of pEGFRThr654 was positively correlated with pDNA-PKThr2609（ R^2= 0. 935）. The inhibitory peptides of EGFR nuclear translocation（ pT654） significantly decreased the expression of nuclear pEGFRThr654 and p DNA-PKThr2609（ R^2= 0. 962）. Conclusion： The inhibitory peptides of EGFR nuclear translocation may inhibit the radiation-induced nuclear EGFR translocation and the DNA-PK activation associated with the NHEJ repair pathway mediated by nuclear EGFR in nasopharyngeal carcinoma cells.