Prohibitin在放射照射诱导鼻咽癌细胞凋亡中的表达及亚细胞定位的变化

目的:探讨放射照射诱导鼻咽癌细胞凋亡中prohibitin(PHB)的表达及亚细胞定位的改变。方法:体外培养鼻咽癌细胞系CNE-1和CNE-2,应用流式细胞术测定4 Gy X线照射前后CNE-1和CNE-2的凋亡率,Western blot检测照射前后PHB和凋亡相关蛋白Bax与P53表达水平的变化,同时应用免疫荧光染色分析上述蛋白亚细胞定位的改变。结果:X线照射后24 h,CNE-1和CNE-2细胞凋亡率、PHB蛋白表达以及凋亡相关蛋白Bax与P53的表达均较照射前显著增加(P<0.05或P<0.01)。PHB和P53在照射前均主要定位于细胞核,少量分布于胞浆,照射后胞浆荧光强度明显增加,细胞核荧光强度下降,表现为出核转运。Bax在照射前后未发现明显的细胞定位改变。结论:放射照射诱导的鼻咽癌细胞凋亡可能与PHB和P53表达及亚细胞定位改变有关。

Involvement of prohibitin during radiation-induced apoptosis in nasopharyngeal carcinoma cells

OBJECTIVE:To investigate changes in expression and subcellular localization of prohibitin (PHB) in radiation-induced apoptosis in nasopharyngeal carcinoma cells. METHODS:CNE-1 and CNE-2 cells were cultured in vitro. Their rates of early stage apoptosis after 4 Gy radiation were measured by flow cytometry.Expression of PHB, Bax and P53 proteins were measured by Western blot. In addition, immunofluorescence was used to detect their intracellular locations. RESULTS:At 24 hours after radiation, the apoptosis rates and expression of PHB, Bax and P53 were increased significantly. Before radiation, both PHB and P53 were distributed mainly around the nucleus but much less in the cytoplasm. After radiation, the fluorescence intensity in the cytoplasmic region increased dramatically, while the intensity in the nucleus dropped. It seemed that nuclear export of PHB and P53 were induced by radiation. However, no significant subcellular localization could be found in Bax distribution. CONCLUSION:The radiation-induced apoptosis may be associated with the expression and positional alteration of PHB and P53. Furthermore, PHB and P53 may interact with each other.