喉癌干细胞在放化疗抵抗中的作用机制

目的：探讨喉癌干细胞的分选方法，分析顺铂、放射线联合应用对喉癌肿瘤干细胞的杀伤效应及机制。方法：应用流式细胞仪荧光活化细胞分选技术检测并分选出喉癌Hep-2细胞系中的CD133＋细胞和CD133-细胞，并检测CD133＋细胞亚群的干细胞特性；采用CCK-8试剂盒分别检测顺铂、放射线对两组细胞的生长抑制率；流式细胞仪检测不同干预方案对2组细胞凋亡率及细胞周期分布情况的影响。结果：CD133＋细胞在喉癌Hep-2细胞系中占（2．43±0．77）％，在细胞增殖、分化及体内成瘤试验中CD133＋细胞均表现出肿瘤干细胞特性；不同浓度剂量的顺铂、放射线对Hep-2细胞均有抑制作用，并在一定浓度范围内呈剂量依赖性；顺铂、放射线单独或联合应用时，CD133-细胞凋亡率显著高于CD133＋细胞（P〈0．01），并产生G0／G1期阻滞。结论：CD133＋细胞较CD133-细胞更具有明显的肿瘤干细胞特性，对放化疗具有明显的抵抗作用，对凋亡诱导作用不敏感和细胞周期改变为其机制之一。

Neoplasms stem cells play an important role in resistance of laryngeal squamous cancer to chemoradiotherapy

Objective：To determine an approach enriching cancer stem cells from laryngeal cancer cell line. lo investigate whether laryngeal cancer stem cells in chemoradiotherapy have the characteristic of resistance. Method.. CD133＋ cells and CD133- cells was detected and isolated from Hep-2 cell line by fluorescence activated cell sorting technology. The cytotoxicities of cisplatin and radiation were investigated by cell counting kit-8 （CCK-8） assay. The apoptosis and cell cycle was analyzed with flow cytometry. Result： CD133＋ cells accounted for a fraction of （2.43±0.77）% in Hep-2 cell line. CD133＋ cells have a more obvious characteristics of cancer stem cells. Different cisplatin and radiation concentrations of for two cell have inhibition, in a certain concentration range and the dosage dependence. Cisplatin and radiation had synergistic inhibitory effects with CD133- cells on the growth of two cell. Moreover, cell cycle arrest at G0/G1 phase and more apoptosis was induced by synergistic combination. Different concentrations of cetuximab for Hep-2 cells have inhibition, in a certain concentration range and time and the dosage dependence. The half maxial inhibitory concentration （IC50） of cetuximab to Hep-2 cells on 24 h was 1 036.84 ug/L. Cisplatin and radiation had synergistic inhibitory effects with cetuximab on the growth of Hep-2 cell line. Moreover, cell cycle arrest at G0/G1 phase and more apoptosis was induced by synergistic combination. Con clusion：Compared with CD133- cells, CD133＋ cells subpopulation exhibited extraordinary cancer stem.