Park Miki Susanto, Okochi Hideaki, Benet Leslie Z
Arch Drug Inf. 2011 Mar;4(1):1-9. doi: 10.1111/j.1753-5174.2010.00032.x.
Studies using MDCKII and LLC-PK1 cells transfected with MDR1 cDNA indicate that ciprofloxacin is not a substrate of P-glycoprotein. However, our data has shown that transport studies done using different P-gp overexpressing cell lines (MDCKI-MDR1, MDCKII-MDR1 and L-MDR1), could lead to contradictory conclusion on whether a compound is a substrate of P-gp. The aim of our study was to determine if ciprofloxacin is indeed not a P-glycoprotein substrate using MDCKI cells transfected with human MDR1 cDNA. METHODS: Semi-quantitative RT-PCR was used to determine the mRNA level of MDR1 while Western blot was performed to determine the protein expression level of P-gp, MRP1 and MRP2 in various cells. Ciprofloxacin bidirectional transport studies were performed in MDCKI, MDCKI-MDR1, MDCKII, MDCKII-MDR1, MDCKII-MRP2, LLC-PK1, L-MRP1 and L-MDR1 cells. RESULTS: Ciprofloxacin showed net secretion in MDCKI-MDR1 but net absorption in MDCKI cells. Various P-gp inhibitors decreased the B to A and increased the A to B transport of ciprofloxacin in MDCKI-MDR1 cells while having no effect in MDCKI cells. The B to A transport of ciprofloxacin in MDCKI-MDR1 cells was not affected by non-P-gp inhibitors. In the presence of indomethacin, ciprofloxacin showed net secretion instead of net absorption in MDCKI cells while in the presence of probenecid and sulfinpyrazone, there was no net secretion and absorption. There was no difference in ciprofloxacin transport between MDCKII and MDCKII-MDR1, LLC-PK1 and L-MDR1, LLC-PK1 and L-MRP1 and MDCKII and MDCKII-MRP2. CONCLUSIONS: Transport data in MDCKI and MDCKI-MDR1 cells indicate that ciprofloxacin is a substrate of P-gp but data from MDCKII, MDCKII-MDR1, LLC-PK1 and L-MDR1 cells indicate that ciprofloxacin is not a substrate of P-gp. Vinblastine, a well-known P-gp substrate, also did not show differences between LLC-PK1 and L-MDR1 cells. Further studies need to be performed to characterize these P-gp overexpressing cell lines and the transport of ciprofloxacin.
使用转染了MDR1 cDNA的MDCKII和LLC-PK1细胞进行的研究表明，环丙沙星不是P-糖蛋白的底物。然而，我们的数据表明，使用不同的P-糖蛋白过表达细胞系（MDCKI-MDR1、MDCKII-MDR1和L-MDR1）进行的转运研究，可能会得出关于一种化合物是否为P-糖蛋白底物的相互矛盾的结论。我们研究的目的是使用转染了人MDR1 cDNA的MDCKI细胞来确定环丙沙星是否确实不是P-糖蛋白底物。方法：采用半定量RT-PCR测定MDR1的mRNA水平，同时进行蛋白质印迹法以确定各种细胞中P-糖蛋白、多药耐药相关蛋白1（MRP1）和多药耐药相关蛋白2（MRP2）的蛋白表达水平。在MDCKI、MDCKI-MDR1、MDCKII、MDCKII-MDR1、MDCKII-MRP2、LLC-PK1、L-MRP1和L-MDR1细胞中进行环丙沙星的双向转运研究。结果：环丙沙星在MDCKI-MDR1细胞中表现为净分泌，而在MDCKI细胞中表现为净吸收。各种P-糖蛋白抑制剂降低了环丙沙星在MDCKI-MDR1细胞中的B到A转运，并增加了A到B转运，而在MDCKI细胞中无作用。环丙沙星在MDCKI-MDR1细胞中的B到A转运不受非P-糖蛋白抑制剂的影响。在吲哚美辛存在下，环丙沙星在MDCKI细胞中表现为净分泌而非净吸收，而在丙磺舒和磺吡酮存在下，既无净分泌也无净吸收。MDCKII与MDCKII-MDR1、LLC-PK1与L-MDR1、LLC-PK1与L-MRP1以及MDCKII与MDCKII-MRP2之间的环丙沙星转运无差异。结论：MDCKI和MDCKI-MDR1细胞中的转运数据表明环丙沙星是P-糖蛋白的底物，但MDCKII、MDCKII-MDR1、LLC-PK1和L-MDR1细胞的数据表明环丙沙星不是P-糖蛋白底物。长春碱是一种众所周知的P-糖蛋白底物，在LLC-PK1和L-MDR1细胞之间也未显示出差异。需要进一步研究来表征这些P-糖蛋白过表达细胞系以及环丙沙星的转运情况。
