白血病细胞株耐药与核因子κB蛋白质诱导表达的关系

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

目的 :探讨慢性粒细胞性白血病细胞 K5 6 2与其耐药株 K5 6 2 /ADR细胞中 IκB- α和 NF- κB的表达 ,以及三氧化二砷 (As2 O3 )诱导白血病细胞凋亡的关系。方法 :应用不同浓度的 As2 O3 诱导 K5 6 2和 K5 6 2 /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 :As2 O3 诱导 K5 6 2 /ADR细胞凋亡率明显低于 K5 6 2细胞 ,当 As2 O3 浓度为 1μmol/L时 ,两种细胞凋亡率分别是 (6 .33± 1.5 1) %、(13.2 5± 1.83) % ,当 As2 O3 浓度增高到 4μmol/L时 ,细胞凋亡率则分别为 (8.0 0±1.4 7) %、(5 0 .5 6± 8.6 2 ) % (P<0 .0 5 )。在 K5 6 2细胞胞浆中 ,IκB-α阳性表达率则由 (88.0 7± 0 .99) %减少到 (4 9.2 1± 0 .95 ) % (P<0 .0 1) ,胞核中 P6 5量逐渐增加 ;而 K5 6 2 /ADR细胞中无明显变化。结论 :As2 O3 可诱导 K5 6 2细胞凋亡 ,伴有 IκB-α的降解及 NF-κB的激活 ;K5 6 2 /ADR细胞 NF-κB表达增加 ,对 As2 O3

Objective: To explore the relationship between drug resistance of leukemic cells and the expression of both IκB α and NF κB associated with apoptosis induced by arsenic trioxide(As 2O 3)in K562 and K562/ADR cells. Methods: Apoptosis was induced in K562 and K562/ADR cells cultured with As 2O 3 in different concentrations. Western blot was used to analyze the expression of NF κB in nuclear and IκB α in cytoplasm of these cells. Apoptosis and degradation of IκB α protein were also observed by flow cytometry. Results: After exposure to As 2O 3, 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 μmol/L As 2O 3 were in apoptosis. When cultured with 4 μmol/L As 2O 3, the apoptosis cells increased to (8 00±1 47)% and (50 56±8 62)%, respectively. The level of IκB α in K562 cytoplasm was down regulated from 88 07% to 49 21% after As 2O 3 stimulation, while NF κB in nuclear was up regulated, that was not found in K562/ADR cells. Conclusion: As 2O 3 could induce apoptosis of K562 cells, associated with the degradation of IκB α and the activation of NF κB. There are an elevated expression of NF κB and resistance to apoptosis induced by As 2O 3 in K562/ADR cells.