柴胡皂苷在体外对人白血病细胞株K562/ADM多药耐药性的逆转作用

目的: 研究柴胡皂苷(SS)对白血病细胞株K562/ADM 多药耐药性(MDR)的逆转作用,并进一步探讨其耐药逆转机制。方法: 分别以不同浓度(1~100 mg/L)的SS作用于体外培养的K562和K562/ADM 细胞48 h,采用MTT 法检测细胞增殖抑制率,确定SS的非毒性剂量;采用非毒性剂量SS 1.25、2.5和5.0 mg/L,分别与不同浓度(0.05~100 mg/L)阿霉素(ADM)联合作用,检测各组细胞生长抑制50%的ADM浓度(IC₅₀),计算逆转指数和两药相互作用系数(CDI),观察SS协同ADM作用后的细胞形态;利用流式细胞术检测SS联合ADM作用后K562/ ADM细胞内ADM的蓄积程度、细胞凋亡和细胞周期变化。结果: 随着SS浓度的增加,细胞增殖抑制率也相应增加,呈剂量-效应关系;SS的非细胞毒性剂量为5.0 mg/L,逆转倍数为21.5倍;SS协同ADM作用后形态学方法显示肿瘤细胞数量减少,并出现了大量凋亡细胞,呈剂量-效应关系;SS可明显提高ADM在K562/ADM细胞内的蓄积,与未加SS对照组比较差异显著(P<0.05);SS可增强ADM对K562/ADM细胞的凋亡诱导作用,与未加SS对照组比较差异显著(P<0.05);K562/ADM细胞被阻滞在G₀/G₁期,与未加SS对照组比较差异显著(P<0.05)。结论: SS对白血病耐药细胞株K562/ADM有增殖抑制和逆转多药耐药性的作用,其部分逆转机制可能是通过增加细胞内化疗药物蓄积,诱导细胞凋亡和使细胞阻滞在G₀/G₁期而实现的。

Reverse effects of saikoside on multidrug resistance of human leukemic cell line K562/ADM in vitro

AIM: To study the reverse effects of saikoside(SS) on the multidrug resistance(MDR) of human leukemic cell line K562/ADM and to investigate the related mechanism.METHODS: K562 cells and K562/ADM cells in the culture were treated with SS at the concentrations of 1~100 mg/L.The inhibitory rate of the cell proliferation was measured by MTT assay.Non-cytotoxic dose of SS was determined.K562/ADM cells were treated with SS at non-cytotoxic doses of 1.25,2.5 and 5.0 mg/L with different concentrations of adriamycin(ADM,0.05~100 mg/L).The 50% inhibitory concentration(IC50) and the reversal index in all groups were determined.The cell morphology was observed after treated with SS+ADM.The effects of SS on ADM accumulation in K562/ADM cells,the cell cycle profile and apoptosis were examined by flow cytometry.RESULTS: The inhibitory rates were significantly increased in a dose-dependent manner when the cells were treated with different doses of SS(1~100 mg/L).The available reversal concentration of SS was 5.0 mg/L and the reversal index was 21.5 folds for K562/ADM cells.After treated with SS+ADM,the number of tumor cells was decreased and apoptotic cells were increased in a dose-response relationship.ADM accumulation in K562/ADM cells treated with SS was significantly higher than that in control cells(P<0.05).SS may significantly enhanced the apoptosis of K562/ADM cells treated with ADM(P<0.05).K562/ADM cells treated with SS were blocked in the stage of G0/G1.CONCLUSION: SS has effect on proliferation inhibition and MDR reversal in K562/ADM cell line.The reversal mechanisms of SS may be due to increasing the accumulation of chemo therapeutics in the cell,inducing the cell apoptosis and arresting the cells in G0/G1 phase.