人鼻咽癌细胞株自发性凋亡与放射敏感性的研究

Relationship between spontaneous apoptosis and radio-sensitivity in well and poorly differentiated nasopharyngeal carcinoma cell lines

目的:探讨鼻咽癌细胞自发性凋亡对放射敏感性的预测意义及自发性凋亡水平差异的分子学基础。方法:克隆形成实验测定人鼻咽高分化鳞癌细胞株(CNE-1)、人鼻咽低分化鳞癌细胞株(CNE-2)接受Varian加速器单野照射(6 MV X线)的存活分数,单击多靶和线性二次模型拟合辐射剂量存活曲线并求出放射生物学参数;流式细胞术检测自然生长2、4、6、8d细胞凋亡情况;RT-PCR、Western blot检测凋亡相关基因Bcl-2、Bcl-xl、Bcl-w、Bax、Bad、Bid、Bak转录及蛋白表达水平。结果:函数模型参数显示CNE-2较CNE-1具有更高的辐射敏感性;相同培养天数下CNE-2早期及晚期凋亡率显著高于CNE-1(P<0.05);CNE-2中Bcl-2、Bcl-xl、Bcl-w、Bax、Bad、Bid、Bak基因转录及蛋白表达水平均高于CNE-1(P<0.05)。结论:自发性凋亡可能成为放射敏感性的预测指标,自发性凋亡水平差异可能与凋亡相关基因差异性表达有关。

Objective：This study aims to investigate spontaneous cell apoptosis in the prediction of the radio-sensitivity of naso-pharyngeal carcinoma （NPC） cells and the molecular foundation of differential spontaneous apoptosis rate. Methods：The surviving fractions and radiation biological parameters of well and poorly differentiated NPC cell lines （CNE-1/CNE-2） were determined through colony-forming assay and radiation dose-survival curve using a single-hit multi-target model and a linear quadratic model. Early-and late-stage apoptotic events were detected by flow cytometry on days 2, 4, 6, and 8. The mRNA and protein expression levels of apoptosis-correlated genes （Bcl-2, Bcl-xl, Bcl-w, Bax, Bad, Bid, and Bak） were detected using RT-PCR and western blot. Results：CNE-2 was more radio-sensitive than CNE-1, and CNE-2 exhibited higher rates of early-and late-stage apoptotic events than CNE-1 on the same culture days （P〈0.05）. The mRNA and protein expression levels of Bcl-2, Bcl-xl, Bcl-w, Bax, Bad, Bid, and Bak were significantly higher in CNE-2 than in CNE-1（P〈0.05）. Conclusion：The radio-sensitivity of NPC cells can be detected based on their spontaneous apoptosis rate, which is related to the different expression levels of apoptosis-correlated genes.