白血病细胞株耐药与核因子κB蛋白质诱导表达的关系

目的:探讨慢性粒细胞性白血病细胞K562与其耐药株K562/ADR细胞中IκB-α和NF-κB的表达,以及三氧化二砷(As2O3)诱导白血病细胞凋亡的关系.方法:应用不同浓度的As2O3诱导K562和K562/ADR细胞凋亡,以Western-blot免疫印迹电泳检测NF-κB、IκB-α的表达,流式细胞术检测细胞凋亡及分析IκB-α的阳性表达率变化.结果:As2O3诱导K562/ADR细胞凋亡率明显低于K562细胞,当As2O3浓度为1 μmol/L时,两种细胞凋亡率分别是(6.33±1.51)%、(13.25±1.83)%,当As2O3浓度增高到4 μmol/L时,细胞凋亡率则分别为(8.00±1.47)%、(50.56±8.62)%(P＜0.05).在K562细胞胞浆中,IκB-α阳性表达率则由(88.07±0.99)%减少到(49.21±0.95)%(P＜0.01),胞核中P65量逐渐增加;而K562/ADR细胞中无明显变化.结论:As2O3可诱导K562细胞凋亡,伴有IκB-α的降解及NF-κB的激活;K562/ADR细胞NF-κB表达增加,对As2O3诱导的反应无明显改变.

Relationship between drug resistance and the expression of NF-κB induced in leukemic cells

OBJECTIVE: To explore the relationship between drug resistance of leukemic cells and the expression of both IkappaB-alpha and NF-kappaB associated with apoptosis induced by arsenic trioxide (As2O3) in K562 and K562/ADR cells. METHODS: Apoptosis was induced in K562 and K562/ADR cells cultured with As2O3 in different concentrations. Western blot was used to analyze the expression of NF-kappaB in nuclear and IkappaB-alpha in cytoplasm of these cells. Apoptosis and degradation of IkappaB-alpha protein were also observed by flow cytometry. RESULTS: After exposure to As2O3, the ratio of apoptosis cells in K562/ADR was significantly lower than that in K562 cells. K562/ADR (6.33+/-1.51)%] and K562 cells (13.25+/-1.83)%] cultured with 1 micromol/L As2O3 were in apoptosis. When cultured with 4 micromol/L As2O3, the apoptosis cells increased to (8.00+/-1.47)% and (50.56+/-8.62)%, respectively. The level of IkappaB-alpha in K562 cytoplasm was down-regulated from 88.07% to 49.21% after As2O3 stimulation, while NF-kappaB in nuclear was up-regulated, that was not found in K562/ADR cells. CONCLUSION: As2O3 could induce apoptosis of K562 cells, associated with the degradation of IkappaB-alpha and the activation of NF-kappaB. There are an elevated expression of NF-kappaB and resistance to apoptosis induced by As2O3 in K562/ADR cells.