紫杉醇和吉西他滨对鼻咽癌HNE_2细胞系协同放射增敏的作用

 目的观察紫杉醇、吉西他滨两药联合对鼻咽癌细胞系HNE2的放射增敏作用,并探讨其可能机制。方法将HNE2细胞分为单纯照射组、吉西他滨(GE)+照射组、紫杉醇(PA)+照射组及GE+PA+照射组,用克隆形成实验计算两药物单用及合用的放射增敏比,流式细胞仪法分别检测、比较各组的细胞凋亡率及细胞周期变化。Westernblot法测定各组细胞凋亡相关基因bcl-2、bax的表达水平。结果吉西他滨、紫杉醇及两药联合使用的放射增敏比分别为1.06、1.13和1.34。流式细胞仪检测显示吉西他滨联合射线主要诱导S期阻滞(96.03%),诱导凋亡率为31.62%;紫杉醇联合射线引起的阻滞以G2+M期为主(75.71%),诱导细胞凋亡率为44.56%;两药合用并联合照射后G2+M期比例(65.98%)有所下降,同时S期比例(33.33%)有所上升(与PA+放射组比较),细胞凋亡率达到73.28%。在四组中bcl-2的表达呈逐步下降趋势,而bax的表达则呈逐步上升趋势。结论吉西他滨、紫杉醇单用及两药联合对鼻咽癌细胞系HNE2均有放射增敏作用,且两者协同增敏作用显著高于单独增敏作用,显示了两药联合应用有助于提高鼻咽癌的放射敏感性。两...

The Synergistic Radiosensitization of Paclitaxel and Gemcitabine on Nasopharyngeal Carcinoma Cell line HNF2

Objective To observe the synergistic radiosensitization of paclitaxel(PA) and gemcitabine(GE), along with their mechanism on nasopharyngeal carcinoma(NPC) cell line HNE_ 2 . Methods Cytotoxicity was performed by exposing HNE_ 2 cells to GE or PA or GE plus PA, followed by irradiation. The Radiation Enhancement Ratio(RER)was evaluated by clonogenic assay. Cell cycle distribution and apoptosis were assessed by flow cytometry. The bcl-2 and bax protein expression were detected by Western Blot. Results The ERE of GE, PA and combined therapy was 1.06 , 1.13 , 1.34 ,respectively. The rate of S phase block and apoptosis related to GE was 96.03 % and 31.62 %, respectively, being 75.71 % G_ 2 /M phase block and 44.56 % apoptosis by PA. For cocktail therapy,the ratio of G_ 2 /M phase arrest induced by PA was decreased from 75.71 % to 65.98 %, while the ratio of S phase block was increased to 33.33 %,together with more apoptosis observed( 73.28 %). Western blot showed that both GE and PA increased the level of Bax expression and inhibited the level of bcl-2 expression. When PA and GE combined, they further increased Bax and inhibited bcl-2 protein expression. Conclusion PA and GE can enhance radiosensitization independently for HNE_ 2 cells. When combined,they showed synergistic effect. And it indicated that the radiosensitizing effects of both drugs could be related to apoptosis.