Action mechanism and clinical application of leukotriene receptor antagonist as multidrug resistance protein 1 (MRP1) modulator

本课题的研究目的是阐明肿瘤细胞耐药的机制，开发有效的耐药调节剂。多药耐药可以通过多药耐药蛋白1（MRP 1）的过表达来介导。MRP作为跨膜外排泵发挥作用，减少细胞内药物积聚，从而产生多药耐药性。克服MRP1介导的多药耐药的方法之一是使用抑制剂来阻断MRP1的功能。这被称为MRP1调制器。迄今为止，几种MRP 1调节剂已进入研究和临床试验。近年来，白三烯受体拮抗剂（LTRA）被认为是MRP1的调节剂之一。我们研究了LTRA克服耐药的效果，并开发了原创的候选药物。在我们的研究期间，我们得到了以下结果：通过两种方法建立耐药癌细胞。细胞从Jurkat（人白血病细胞系）中通过长期暴露于阿霉素超过2个月并转染MRP 1cDNA来选择。在耐药细胞中，MRP 1的过度表达是由于扩增的MRP基因转录的MRP mRNA水平增加所致。在药物敏感的Jurkat和MRP过表达的耐药细胞中检查了在存在或不存在多柔比星的情况下LTRA的剂量反应效应。LTRA逆转Jurkat耐药性。荧光累积分析揭示了在抗性Jurkat预孵育的LTRA中荧光的显著增加。通过对细胞内谷胱甘肽含量的测定、ATP酶活性的测定、细胞周期途径的分析，科学地证明了LTRA对MRP 1的调节作用。我们现在已经写好了报告。

Our purpose of research is to clarify the mechanism of anticancer drug resistance by tumor cells and developing effective resistance modulators. Multidrug resistance can be mediated by overexpression of the multidrug resistance protein 1(MRP1). MRP function as transmembrane efflux pumps, which decrease intracellular drug accumulation, thereby conferring multidrug resistance. One of the ways to overcome MRP1 mediated multidrug resistance is to use an inhibitor to block the function of MRP1. This is called MRP1 modulator. To date, several MRP1 modulator have entered study and clinical trials. Recently, leukotriene receptor antagonist(LTRA) is thought to be one of the MRP1 modulator. We studied effect to overcome drug resistance by LTRA and have developed original candidate medications.In our study duration, we got results as below; The resistance cancer cells was established by two methods. The cells were selected from Jurkat (human leukemia cell line) by chronic exposure to doxorubicin over 2 months and transfection of MRP1cDNA. In the resistant cells, the overexpression of MRP1 resulted from an increased MRPmRNA level transcribed from amplified MRP gene. The dose-response effects of LTRA in the presence or absence of doxorubicin were examined in both drug-sensitive Jurkat and MRP-overexpressing resistant cells. LTRA reversed Jurkat resistance. The fluorescent accumulation analysis revealed a significant increase of fluorescence in resistant Jurkat pre-incubated LTRA. We demonstrated that LTRA modulate MRP1 scientifically by the measurement of intracellular glutathione, ATPase assay, analysis of cell-cycle pathway. We have written the report now.