咯萘啶逆转肿瘤多药耐药及其作用机制

目的:利用mdr1~ 的人白血病和乳腺癌多药耐药(MDR)细胞系K562/A02和MCF-7/ADR研究咯萘啶(pyronaridine,PND)对MDR的逆转作用及其机制.方法:采用MTT法、荧光分光光度法、荧光显微镜法、流式细胞仪法和RT-PCR法分别测定PND单独或与阿霉素(DOX)合用,对肿瘤细胞的生长抑制、诱导凋亡、细胞内药物浓度、mdr1基因表达的影响.结果:PND对敏感及耐药细胞均具有生长抑制作用,半数抑制剂量(IC_(50))根据不同细胞在5.10-18.66μmol/L之间;低毒剂量PND显著增强DOX对耐药细胞的细胞毒和诱导凋亡作用,且增加DOX在耐药细胞内的蓄积及减少罗丹明(Rh123)的外排.RT-PCR结果显示,PND对mdr1基因无下调作用.结论:PND可作为第三代P-糖蛋白(P-gp)抑制剂,通过下调P-gp药物外排泵功能而产生强大的逆转MDR效应.

Function and mechanism of pyronaridine: a new inhibitor of P-glycoprotein-mediated multidrug resistance

AIM: To study the effect and mechanism of pyronaridine (PND) on the reversal of multidrug resistance (MDR) in K562/A02 and MCF7/ADR cell lines with mdr1+. METHODS: MTT assay was used to determine the cells growth inhibition after incubation for 72 h in the presence of doxorubicin (DOX) with or without PND. Intracellular accumulation of DOX was analyzed by spectrofluorometry. P-glycoprotein (P-gp) activity was investigated by measuring the extrusion of the cationic dye rhodamine 123 (Rh123). The apoptosis of cells and mdr1 gene expression were detected using flow cytometry and RTPCR, respectively. RESULTS: PND slightly inhibited the growth of MDR human leukemia, breast cancer cells, and their parental cell lines. The IC50 of PND were 5.10 - 18.66 micromol/L depending on the kinds of cell lines. PND at low toxic concentrations enhanced antiproliferative effect of DOX on MDR cells and the apoptosis induced by DOX in a concentration-dependent manner. Intracellular accumulation of DOX and Rh123 in MDR cell lines increased after combination with PND. PND did not down-regulate mdr1 gene expression in MDR cell lines K562/A02 and MCF7/ADR. CONCLUSION: As the third-generation Pgp inhibitor, PND significantly reversed MDR in MDR cell lines K562/A02 and MCF7/ADR by inhibiting P-gp function.