伊沙匹隆影响乏氧或静息状态下非小细胞肺癌细胞放射敏感性

The effect of Ixabepilone on NSCLC cells radio-sensitivity under quiescent or hypoxic condition

目的 评价伊沙匹隆对乏氧或静息状态下非小细胞肺癌（NSCLC）细胞放射敏感性的影响.方法 以人NSCLC细胞系NCI-H460和A549为研究对象,分别进行乏氧处理和静息诱导,以未处理细胞为对照,集落形成实验观察伊沙匹隆联合2 Gyγ射线照射后细胞存活情况,流式细胞术与蛋白印迹分析分别检测细胞周期与凋亡.结果乏氧或静息诱导均会引起G1期细胞比例的大幅增加（NCI-H46细胞系P=0.001 3;A549细胞系P=0.006）,明显高于对照组,并伴随着细胞放射敏感性显著降低（细胞存活分数：NCI-H460细胞系P=0.003;A549细胞系P=0.000 1）.伊沙匹隆可以诱导NSCLC的凋亡,联合γ射线作用时可以显著增强乏氧细胞的放射敏感性（细胞存活分数下降：NCI-H460细胞系P=0.000 2;A549细胞系P＜0.01）.结论 实体肿瘤组织中存在的乏氧或静息期细胞对射线的敏感性差,伊沙匹隆具有良好的诱导NSCLC凋亡的作用,并对乏氧细胞有较好的放射增敏作用,可通过进一步的整体试验确认其效果,为临床实践提供理论支持.

Objective To evaluate the effect of Ixabepilone on quiescent or hypoxic cells response to ionizing radiation.Methods NCI-H460 and A549,two human NSCLC cell lines,were employed in this experiment.Quiescent cells （QC） or hypoxic cells （HC） were induced as mentioned previously and untreated cells as control.A colony forming assay was applied to compare cellular radio-sensitivity with or without Ixabepilone.Flow cytometry and Western blot analysis were used to detect cell cycle distribution and apoptosis.Results Along with an increased population of G1 cell （NCI-H46 P =0.001 3;A549 P =0.006）,both HC and QC were exhibited radio-resistance compared to untreated cells （survival fraction：NCI-H460 P =0.003;A549 P =0.000 1）.Moreover,it was found that Ixabepilone,which induced apoptosis in both IR-treated or untreated NSCLC cells,significandy enhanced cells death under hypoxia （decrease of survival fraction：NCI-H460 P =0.000 2;A549 P 〈 0.01）.Conclusion The existence of quiescent or hypoxic cells in solid tumors poses a critical therapeutic problem since they were resistant to IR.Ixabepilone,which induces apoptosis in NSCLC,showed great radio-sensitization effect on hypoxic cells.Following work will focus on whether Ixabepilone could increase hypoxic tumor cells radio-sensitivity in vivo,which could provide useful data for the application of Ixabepilone in clinical practice.