【摘要】 目的研究钙调素拮抗剂O-4-乙氧基-丁基-小檗胺(EBB)对乳腺癌多药耐药细胞系MCF-7/ADR的耐药逆转作用。方法采用四唑盐(MTT)比色法测定药物敏感性,分析联合应用低剂量EBB(≤IC20)时阿霉素(ADR)对MCF-7/ADR细胞的半数抑制浓度(IC50)值及其增敏倍数;应用流式细胞术测定EBB对细胞周期的影响,同时观察细胞内药物浓度的积累;采用逆转录—多聚酶链反应检测EBB对多药耐药基因-1(mdr1)及拓扑异构酶Ⅱb(topⅡb)mRNA表达水平的影响。结果EBB对MCF-7/ADR的多药耐药具有明显逆转作用,3、7·5μmol/L浓度的EBB可以明显提高MCF-7/ADR对ADR的敏感性,平均增敏倍数分别为50·40、89·80倍,逆转强度明显高于阳性逆转剂维拉帕米(VPL)的14·88倍(P=0·0097)。6μmol/L的EBB处理2h后,细胞内积累的P糖蛋白底物罗丹明123(Rh123)荧光强度峰值发生明显右移;同时EBB可明显增强ADR对MCF-7/ADR细胞在G2/M期的阻滞作用。6和12μmol/L的EBB处理MCF-7/ADR细胞48h后,mdr1的mRNA表达水平有一定的降低趋势,但无统计学差异;topⅡb基因表达差异亦无显著性。结论EBB对MCF-7/ADR细胞具有较强的逆转多药耐药作用,其可能的逆转机制在于增强ADR对耐药细胞在G2/M期的阻滞以及抑制P糖蛋白外排泵作用。更多还原

【Abstract】 Objective To investigate the reversal effect of O-（4-ethoxyl-butyl）-berbamine（EBB）on mutidrug resistance （MDR） in MCF-7/ADR cell. Methods 3-（4,5-dimethyl-2-thiazolyl）-2,5-diphenyl-2H-tetrazolium bromide （MTT） assay was used to assess the antitumor effect of EBB and determine the reversal effects of different concentrations（≤IC 20 ）of EBB on MCF-7/ADR cell. Flow cytometry was applied to observe the intracellular accumulation of Rh123 and cell cycle in the presence of EBB. The expressions of MDR-related genes mdr 1 and topoisomerase Ⅱb（top Ⅱb） were evaluated by reverse transcription-polymerase chain reaction. Results The sensitivity of MCF-7/ADR to adriamycin（ADR）was enhanced up to 50.40、89.80,and 14.88 folds after exposure of the cells to 3μmol/L EBB,7.5μmol/L EBB,and 10μmol/L verapamil（VPL）,respectively. After 2 hours of incubation with 6 μmol/L EBB,intracellular Rh123 accumulation in MCF-7/ADR cells was increased to the level comparable to that in MCF-7 cells. When 6μmol/L EBB was added together with 2μmol/L ADR,MCF-7/ ADR cells showed to be arrested in the G 2 /M phase. The declination of mdr 1 gene expression was observed when 6μmol/L EBB,12μmol/L EBB,and 10μmol/L VPL were added for 48 hours;meanwhile,the expression of topⅡ b mRNA showed no significant change. Conclusion EBB has a strong reversal effect on MDR in MCF-7/ADR cell,which may be achieved by enhancing the arrestment of MCF-7/ADR cells at G₂/M phase and increasing intracellular drug concentration.更多还原