Li Hao, Hui Lulu, Xu Wenlin, Shen Huiling, Chen Qiaoyun, Long Lulu, Zhu Xiaolan
Department of Central Laboratory, The Affiliated People's Hospital, Jiangsu University, Jiangsu, P.R. China.
Oncol Lett. 2012 Feb;3(2):485-489. doi: 10.3892/ol.2011.500. Epub 2011 Nov 30.
Multidrug resistance is a serious obstacle encountered in leukemia treatment. Previous studies have found drug resistance in human leukemia is mainly associated with overexpression of the multidrug resistance gene 1 (MDR1). The aim of the present study was to investigate the modulation of P-glycoprotein expression by triptolide in adriamycin-resistant K562/A02 cells. The reverse effects of triptolide on drug resistance in K562/A02 cells were assessed by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium bromide (MTT) assay. The percentage of apoptotic cells was obtained from annexin V/fluorescein isothiocyanate (FITC) and propridium iodide (PI) double-staining. The effects of triptolide on P-glycoprotein activity were evaluated by measuring intracellular adriamycin accumulation. The expression of P-glycoprotein was determined by flow cytometry. A luciferase reporter gene assay was used to detect the transcriptional activity of the MDR1 promoter. Results revealed that triptolide decreased the degree of resistance of K562/A02 cells, and significantly inhibited P-glycoprotein expression and drug-transport function, and increased the accumulation of adriamycin in K562/A02 cells as measured by flow cytometry. A luciferase reporter gene assay demonstrated that triptolide was capable of inhibiting the transcriptional activity of the MDR1 promoter. Triptolide may effectively reverse the adriamycin resistance in K562/A02 cells via modulation of the P-glycoprotein expression and by increasing intracellular adriamycin accumulation.
多药耐药是白血病治疗中遇到的一个严重障碍。先前的研究发现，人类白血病中的耐药性主要与多药耐药基因1（MDR1）的过表达有关。本研究的目的是探讨雷公藤内酯醇对阿霉素耐药的K562/A02细胞中P-糖蛋白表达的调节作用。通过3-[4,5-二甲基噻唑-2-基]-2,5-二苯基溴化四氮唑蓝（MTT）法评估雷公藤内酯醇对K562/A02细胞耐药性的逆转作用。凋亡细胞百分比通过膜联蛋白V/异硫氰酸荧光素（FITC）和碘化丙啶（PI）双染获得。通过测量细胞内阿霉素蓄积来评估雷公藤内酯醇对P-糖蛋白活性的影响。通过流式细胞术测定P-糖蛋白的表达。采用荧光素酶报告基因测定法检测MDR1启动子的转录活性。结果显示，雷公藤内酯醇降低了K562/A02细胞的耐药程度，显著抑制了P-糖蛋白的表达和药物转运功能，并通过流式细胞术检测发现增加了阿霉素在K562/A02细胞中的蓄积。荧光素酶报告基因测定法表明，雷公藤内酯醇能够抑制MDR1启动子的转录活性。雷公藤内酯醇可能通过调节P-糖蛋白表达和增加细胞内阿霉素蓄积，有效逆转K562/A02细胞的阿霉素耐药性。
