【摘要】 背景与目的:诱导细胞凋亡是许多化疗药物的作用机制,多药耐药细胞常可以抵抗药物诱导的凋亡,有必要从分子机理上探索其抗凋亡机制。但正是由于耐药细胞的抗凋亡特性,难以在凋亡通路中展开相关研究。本研究用环孢素A(CyclosporinA,CsA)诱导药物敏感的人急性白血病细胞HL-60及其多药耐药细胞HR20和HT9凋亡,通过对二者凋亡通路中的关键分子进行比较,分析耐药细胞与敏感细胞凋亡途径的差别。方法:用10、20mg/LCsA分别处理HL-60、HR20和HT9细胞,用细胞核形态观察、DNA凝胶电泳以及流式细胞术方法鉴定凋亡,通过分光光度法和免疫印迹法检测凋亡过程中相关因子的变化。结果:10、20mg/LCsA处理HL-60、HR20和HT9细胞,能够诱导细胞都发生明显的凋亡,包括染色质凝集、DNA片断化因子(DNAfragmentationfactor,DFF)裂解激活以及DNA断裂,然而仅在HL-60凋亡细胞中检测到Caspase-3活化,而在HR20和HT9凋亡细胞中Caspase-3没有活化。结论:CsA诱导HR20和HT9细胞凋亡的通路可能不依赖于Caspase-3,其凋亡通路中可能存在除Caspase-3以外的DFF活化因子。推测Caspase-3不容易活化可能是HR20和HT9多药耐药的原因之一。更多还原

【Abstract】 BACKGROUND &OBJECTIVE: Multidrug resistant (MDR) cells can resis t drug-induced apoptosis, which is the functional mechanism for many chemotherape utic drugs. It is necessary to search for the molecular mechanism underlying ant i-apoptosis of MDR cells. However, because of the anti-apoptosis characteristi c of MDR cells, it is hard to study the mechanism on their apoptosis pathway. Th is study was to induce apoptosis in human acute leukemia cell line HL-60, and i ts MDR cell lines HR20 and HT9 by cyclosporin A (CsA), analyze the differences i n apoptosis pathway between MDR cells and sensitive cells by detecting several i mportant apoptosis-related molecules. METHODS: HL-60, HR20, and HT9 cells were treated with 10, and 20 mg/L of CsA, cell apoptosis was identified by cell morp hologic changes,electrophoresis,and flow cytometry. Changes of apoptosis-relate d factors were detected by spectrophotometer and Western blot. RESULTS: HL-60, HR20, and HT9 cells all showed obvious apoptotic characteristics after treated w ith CsA,such as chromatin condensation, DNA fragmentation factor (DFF) degradati on and activation, and DNA fragmentation. However, Caspase-3 activation was onl y detected in apoptotic HL-60 cells. CONCLUSIONS: CsA may induce apoptosis of H R20, and HT9 cells in a Caspase-3 independent manner, which is different from a poptosis of sensitive cells. In the apoptosis pathway of HR20, and HT9 cells, th ere may be some factors other than Caspase-3 that can activate DFF. It is postu lated that the difficulty of Caspase-3 to be activated may be an important reas on for HR20 and HT9 cells to resist apoptosis induced by many chemotherapeutic d rugs.更多还原