手霉素通过线粒体凋亡途径诱导U937和HL-60细胞凋亡

目的 研究法尼酰基转移酶抑制剂手霉素（Manumycin）诱导白血病细胞凋亡的机制。方法 用2μmol／L手霉素处理白血病细胞系U937和HL-60细胞不同时间，用流式细胞术检测细胞凋亡。免疫印迹技术检测细胞色素C、caspase9、caspase8、caspase3的表达。用荧光染料JC-1检测法测定线粒体膜电位（Δψm），并用caspase抑制剂Z—VAD—fmk阻断caspase的活化，探讨caspase在手霉素诱导白血病细胞凋亡中的作用。结果 2μmol／L手霉素处理U937和HL-60细胞16h，Δψm显著下降，相对值分别是0．51±0．07和0．41±0．06（P〈0．01）。手霉素诱导细胞色素C从线粒体释放到细胞质，激活caspase-9、caspase8和caspase-3。50μmol／L的Z—VAD—fmk可完全阻断caspase激活，但仅部分阻断手霉素诱导的U937和HL-60细胞凋亡，细胞凋亡率分别减少51．69％和56．47％。结论 手霉素通过线粒体途径诱导U937和HL-60细胞凋亡。

Involvement of mitochondria apoptotic pathway in the manumycin inducing apoptosis of U937 and HL-60

OBJECTIVE: To investigate the apoptosis induced by manumycin in U937 and HL-60 cell lines, and to explore the role of mitochondria apoptotic pathway in manumycin-inducing apoptosis. METHODS: Leukemic cells line U937 and HL-60 were treated by manumycin at 2 micromol/L for different time. Apoptosis of leukemia cells was detected by flow cytometry. The cytosolic proteins were extracted using a digitonin buffer. The protein expression of cytochrome C, caspase-9, caspase-8, and caspase-3 were determined by western blot. Mitochondrial membrane potential was detected by JC-1. RESULTS: In U937 and HL-60 cells, manumycin induced mitochondrial depolarization after 6 h treatment. The average red/green fluorescence ratios at 6 h were significantly (P < 0.01) lower than those at time 0, being 0.51 +/- 0.07 and 0.41 +/- 0.06 for control group respectively. Manumycin induced cytochrome C release from the mitochondria into the cytosol after 6 h treatment, and activated caspase-9, caspase-8, and caspase-3 after a 16h treatment. The broad-spectrum caspase-inhibitor Z-VAD-fmk at 50 micromol/L was able to inhibit caspase cleavage completely, but only reduced the manumycin-induced apoptosis rates by 51.69% and 56.47% in U937 and HL-60, respectively. CONCLUSION: Manumycin induced apoptosis in U937 and HL-60 cell lines via mitochondria apoptotic pathway.