5-ALA-PDT对两种鼻咽癌细胞EBV-C666-1和CNE2的杀伤效应研究

目的比较处于不同细胞生长期的EBV-C666-1和CNE2鼻咽癌细胞加入相同浓度5-氨基酮戊酸(5-Aminolevulinic acid,5-ALA)孵育相同时间后,所产生PpⅨ总量的差异以及对PDT的响应情况。方法通过计数法测定C666-1和CNE2细胞的生长曲线,利用荧光光谱技术检测处于不同生长期的细胞吸收5-ALA所生成的PpⅨ含量,应用激光共聚焦显微技术观察5-ALA-PpⅨ在两种细胞中的亚细胞分布。分别在细胞培养24,48和72 h后,对两株细胞进行光动力(photodynamic therapy,PDT)实验,使用CCK-8(cell counting Kit-8)比色法测定细胞存活率。结果 C666-1细胞中5-ALA-PpⅨ的含量明显低于CNE2细胞。同种细胞在不同生长期吸收5-ALA后所生成的PpⅨ的含量也存在显著差异。5-ALA-PpⅨ主要分布在C666-1细胞的线粒体,而在CNE2细胞中主要分布于细胞膜。相同实验条件下,C666-1细胞在培养24和48 h的PDT实验中,存活率低于CNE2,而在细胞培养72 h后的PDT实验中,存活率高于CNE2。结论处于不同生长期的C666-1和CNE2细胞吸收5-ALA后所生成的PpⅨ的含量存在显著差异,细胞中PpⅨ的含量和分布是影响PDT疗效的重要因素。

Efficacy of 5-ALA-PDT in Killing EBV-C666-1 and CNE2 Cells

Objective To investigate the difference between two EBV negative nasopharyngeal carcinoma （NPC） cell lines, namely, C666-1 and CNE2, in 5-ALA-PDT efficacy in different cell growth phases. Methods The cell growth curves for EBV-C666-1 and CNE2 cells were developed by cell counting. Laser-induced fluorescence tech-nique and eonfocal microscope were used to study the accumulated concentration and subeellular localization of 5-ALA-PplX in C666-1 and CNE2 cells respectively. The survival rates of the two＇NPC cell lines were analyzed with CCK-8. Results The PpIX production of CNE2 cells was higher than that of C666-1 cells, and correlated with the growth phases of the cells. After 4 hours＇incubation with 5-ALA, the induced PplX in C666-i cells was found mainly in mitochondria, whereas it concentrated in eytomembrane for CNE2 cells. After the PDT treatment, the survival rate of C666-1 cells was lower than that of CNE2 cells both for 24 and 48 hours＇cultivation respectively, but the rate for 72 hours＇ cultivatiOn was higher. Conclusions The difference between C666-1 and CNE2 cells in PpⅨ production during different growth phases was significant, and the efficacy of 5-ALA-PDT depends on both the concentration and suboellular distribution of 5-ALA induced PpIX.