电离辐射对鼻咽癌CNE-2细胞自噬活性的影响

Effect of ionizing radiation on autophagy of human nasopharyngeal carcinoma cell line CNE-2

目的研究电离辐射对CNE-2细胞自噬活性和EPG5表达的影响。方法 CNE-2细胞用不同剂量电离辐射照射后,透射电镜、qRT-PCR、Western blot分别检测自噬形态、自噬标志物(P62、LC3)及EPG5表达;用RNA干扰技术(siRNA)沉默EPG5基因表达,qRT-PCR及Western blot检测自噬标志物及EPG5表达。结果电离辐射引起自噬小体数量增加、LC3Ⅱ/LC3Ⅰ比值升高(P<0.01)、p62蛋白表达增加、EPG5 mRNA表达下调(P<0.01)。EPG5-siRNA转染后EPG5 mRNA表达下调(P<0.01),P62、LC3Ⅱ蛋白表达升高(P<0.01)。结论电离辐射可能通过下调EPG5基因表达,阻滞自噬溶酶体形成,从而影响CNE-2细胞自噬水平。

Objective To investigate the eefect of ionizing radiation on autophagy and EPG5 expression in human nasopharyngeal carcinoma cell line CNE-2. Methods Autophagic morphology and expression of autophagy markers （P62 and LC3） and EPG5 in ionizing radiation treated CNE-2 cells were detected using transmission electron microscopy, qRT-PCR and Western blot, respectively. In addition, expression of autophagy markers and EPG5 in CNE-2 cells was dtermined by qRT- PCR and Western blot after treatment with small interference RNA（siRNA）. Results Ionizing radiation resulted in the increase of autophagosome number, LC3II/LC3I ratio （P〈0.01） and P62 protein expression but decrease of EPG5 mRNA expression （P〈0.01） in CNE-2 cells. EPG5-siRNA transfection upregulated EGP5 mRNA expression （P〈0.01） but upregulated P62 and LC3II protein expression （P〈0.01） in CNE-2 cells. Conclusion Ionizing radiation might block autolysosome formation by downexpression of EPG5 gene in CNE-2 cells, which can affect the autophagy activity.