【摘要】 本研究旨在探讨5-溴汉防己甲素(BrTet)和汉防己甲素(Tet)对K562/A02细胞多药耐药性的逆转作用。采用MTT法检测阿霉素(ADM)联合应用BrTet、Tet,对K562/A02细胞和K562细胞增殖的影响;采用流式细胞术(FCM)检测细胞内ADM浓度和P糖蛋白(P-gp)的表达;采用RT-PCR测定细胞mdr1基因mRNA表达水平。建立裸鼠皮下移植瘤模型,比较BrTet、Tet在体内的逆转耐药作用。结果发现,BrTet在0.25、0.5以及1μmol/L浓度条件下对K562/A02细胞多药耐药性的逆转作用呈剂量依赖性。流式细胞术检测提示,BrTet显著增加K562/A02细胞内ADM浓度,并呈剂量依赖性,同时抑制P-gp的表达,下调mdr1mRNA的表达。在荷瘤鼠模型中,BrTet明显增加ADM对K562/A02移植瘤的抗肿瘤作用,从单用ADM的5.8%上升至26.1%,而在K562移植瘤中没有显著差异。结论:BrTet在体内体外试验中均显示出显著的逆转MDR作用,其活性可能与抑制P-gp的过度表达和增加抗肿瘤药物的积聚有关。更多还原

【Abstract】 The present study was aimed to evaluate the MDR reversal activity of bromotetrandrine(BrTet) in vitro and in vivo.The inhibitory effects of adriamycin(ADM) used alone or in combination with BrTet or Tet on the proliferation of K562 and K562/A02 cells were evaluated by MTT assay.The ADM accumulation and the protein levels of P-glycoprotein(P-gp) were detected by flow cytometry.The mRNA levels of P-gp were determined by RT-PCR.The in vivo effect of BrTet and Tet was investigated by using nude mice grafted with sensitive human leukemia cell line K562 and MDR cell line K562/A02.The results showed that BrTet at 0.25,0.5 and 1 μmol/L reversed the resistance to ADM in MDR K562/A02 cells in a dose-dependent manner.Flow cytometry suggested that BrTet significantly increased the intracellular accumulation of ADM in K562/A02 cells in a dose-dependent manner.BrTet also inhibited the overexpression of P-gp in K562/A02 cells,and down-regulated mdr1 expression.In nude mice bearing K562 xenografts on the left flank and K562/A02 xenografts on the right flank,intraperitoneal injection of 10 mg/kg BrTet significantly enhanced the antitumor activity of ADM against K562/A02 xenografts with inhibitory rates of 26.1%,while ADM alone inhibited the growth of K562/A02 xenografts only by 5.8%.No enhancement effect by BrTet was seen in K562 xenografts.It is concluded that BrTet shows significant MDR reversal activity in vitro and in vivo.Its activity may be related to the inhibition of P-gp overexpression and the increase intracellular accumulation of anticancer drugs.BrTet may be a promising-MDR modulator for eventual assessment in the clinic.更多还原