Yanagisawa T, Newman A, Coley H, Renshaw J, Pinkerton C R, Pritchard-Jones K
Section of Paediatrics, The Institute of Cancer Research/Royal Marsden NHS Trust, Sutton, Surrey, UK.
Br J Cancer. 1999 Jun;80(8):1190-6. doi: 10.1038/sj.bjc.6990485.
Clinical studies have suggested that both MDR1 and MRP may play a significant role in the chemosensitivity and outcome of neuroblastoma. To clarify the nature of multidrug resistance (MDR) in this tumour a series of six neuroblastoma cell lines have been characterized with regard to P-glycoprotein, MRP and LRP expression using immunocytochemistry and expression of MDR1, MRP, LRP and topoisomerase II genes using reverse transcription polymerase chain reaction (RT-PCR). By RT-PCR, all lines expressed MRP, five expressed LRP and four expressed MDR1, but protein levels of each of these were variable. Chemosensitization to a range of MDR-associated drugs (vincristine, doxorubicin, etoposide, taxotere, topotecan) and non-MDR-associated drugs (cisplatin, melphalan) by three modulating agents, cyclosporin A, PSC 833 and the novel Biricodar (VX-710; Incel), was evaluated using a colourimetric cytotoxicity assay (MTS). Alteration of daunorubicin efflux by these agents was evaluated using FACS analysis. Clonogenic assay was used to study the influence of these chemosensitizers on vincristine cytotoxicity. Marked sensitization to vincristine was observed in MDR1-positive lines, and a similar but less consistent effect was seen with taxotere, doxorubicin and etoposide. With MRP-positive, MDR-negative lines, only VX-710 caused consistent sensitization. These data confirm MDR1 and MRP expression as contributory factors in chemoresistance in neuroblastoma and indicate that VX-710 may be a useful modulator of both mechanisms and worthy of clinical evaluation in this tumour.
临床研究表明，MDR1和MRP可能在神经母细胞瘤的化疗敏感性及预后中发挥重要作用。为阐明该肿瘤中多药耐药（MDR）的本质，使用免疫细胞化学方法对一系列6种神经母细胞瘤细胞系进行了P-糖蛋白、MRP和LRP表达特征分析，并使用逆转录聚合酶链反应（RT-PCR）对MDR1、MRP、LRP和拓扑异构酶II基因的表达进行了分析。通过RT-PCR，所有细胞系均表达MRP，5个表达LRP，4个表达MDR1，但这些蛋白的水平各不相同。使用比色细胞毒性试验（MTS）评估了三种调节剂环孢素A、PSC 833和新型Biricodar（VX-710；Incel）对一系列与MDR相关药物（长春新碱、阿霉素、依托泊苷、多西他赛、拓扑替康）和非MDR相关药物（顺铂、美法仑）的化疗增敏作用。使用流式细胞术分析评估这些药物对柔红霉素外排的影响。克隆形成试验用于研究这些化疗增敏剂对长春新碱细胞毒性的影响。在MDR1阳性细胞系中观察到对长春新碱的显著增敏作用，对多西他赛、阿霉素和依托泊苷也观察到类似但不太一致的效果。在MRP阳性、MDR阴性细胞系中，只有VX-710引起持续增敏。这些数据证实MDR1和MRP表达是神经母细胞瘤化疗耐药的促成因素，并表明VX-710可能是这两种机制的有效调节剂，值得在该肿瘤中进行临床评估。
