甲诺孕酮和屈洛昔芬对K562/A02细胞株多种耐药机制的调节

Modulation of multiple drug resistance by nomegestrol acetate and droloxifene in K562/A02

目的研究甲诺孕酮（ＮＯＭ）和屈洛昔芬（ＤＲＯ）对Ｋ５６２／Ａ０２细胞株耐药基因ｍｄｒ１、谷胱甘肽Ｓ转移酶（ＧＳＴπ）、拓扑异构酶Ⅱα（ＴｏｐｏⅡα）和多药耐药相关蛋白（ＭＲＰ）的调节。方法应用细胞培养技术，采用ＭＴＴ比色法、免疫组织化学、逆转录聚合酶链反应和流式细胞术分析。结果ＮＯＭ和ＤＲＯ均可明显提高Ｋ５６２／Ａ０２细胞株对阿霉素（ＡＤＭ）的敏感性，增加细胞内ＡＤＭ积累量。可显著下调ｍｄｒ１、ＧＳＴπ的ｍＲＮＡ和蛋白表达，明显上调ＴｏｐｏⅡα基因表达。Ｋ５６２敏感株的ＧＳＴπ基因表达同样被抑制。都具有明显的时间依赖性。ＭＲＰ基因表达的变化差异无统计学意义。结论ＮＯＭ和ＤＲＯ可明显逆转Ｋ５６２／Ａ０２细胞株对ＡＤＭ的耐药性。ＮＯＭ与异搏定逆转强度相似；两药对ｍｄｒ１、ＧＳＴπ和ＴｏｐｏⅡα基因表达均有明显调节作用。调节呈时间依赖性。

Objective To study the modulation of mdr1, glutathione Stransferase Pi (GST), topoisomerase (Topo) and multidrug resistanceassociated protein (MRP) by nomegestrol acetate (NOM) and droloxifene (DRO) in K562 cell line. Methods Adriamycin (ADM)resistant K562 (K562/A02) and parental K562 cells were treated with NOM and DRO. The alterations of chemosensitivity to ADM were evaluated by MTT assay, mRNA and protein expression of drugresistant gene by RTPCR and immunohistochemistry and accumulation of ADM by flow cytometry (FCM). Results Both NOM and DRO markedly enhanced chemosensitivity to ADM of K562/A02 cells. After 20, 10 and 5mol/L of NOM or DRO treatment, the chemosensitivities to ADM were increased by 17.7, 15.1 and 5.1 times, respectively in NOM treated cells and by 12.3, 12.9 and 4.0 times, respectively in DRO treated cells. In both the drugs treated cells the accumulation of ADM was increased by 23 times. The MDR reversal activity of NOM was similar to that of VRP, but the modulatory action of DRO on K562/A02 cells was weaker than that of VRP at concentration of 20mol/L. After 20mol/L of NOM treatment, chemosensitivity to ADM of K562 cells was markedly enhanced ( P <0.05). Both NOM and DRO were found to significantly inhibit mdr1 and GST expression and increase Topo expression at the mRNA and protein level. This modulation of gene expression was time dependent and the maximal effects appeared 5 days after drugs treatment. Both NOM and DRO failed to modulate the MRP expression. In K562 cells, NOM and DRO also inhibited GST expression ( P <0.05). Conclusion Both NOM and DRO could markedly reverse the MDR of K562/A02 cells. The reversal activity of NOM was comparable to that of VRP. Both the drugs could modulate mdr1, GST and Topo expression in a time dependent manner.