Delineating the contribution of secretory transporters in the efflux of etoposide using Madin-Darby canine kidney (MDCK) cells overexpressing P-glycoprotein (Pgp), multidrug resistance-associated protein (MRP1), and canalicular multispecific organic anion transporter (cMOAT)
Delineating the contribution of secretory transporters in the efflux of etoposide using Madin-Darby canine kidney (MDCK) cells overexpressing P-glycoprotein (Pgp), multidrug resistance-associated protein (MRP1), and canalicular multispecific organic anion transporter (cMOAT)
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DOI：
10.1124/dmd.30.4.457
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发表时间：
2002-04-01
影响因子：
3.9
通讯作者：
Sinko, PJ
中科院分区：
文献类型：
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作者：
Guo, A;Marinaro, W;Sinko, PJ
肿瘤细胞的多药耐药往往是由外排转运体“泵”的表达介导的。人们还认为，许多相同的转运体参与了肠、脑、肾和肝脏中许多正常的内皮细胞和上皮细胞的药物外流。在Caco-2细胞和建立良好的Madin-Darby犬肾(MDCKII)细胞系中，研究了依托泊苷的转运动力学，以确定这些转运体在依托泊苷外流中的作用。依托泊苷转运动力学：在MDCKII-MDR1和MDCKII-cMOAT细胞中呈浓度依赖性。其表观分泌米氏常数(K-m)和载体介导的通透性(P-o)值分别为254.96+/-94.39um和5.96+/-0.41x10(-6)cm/S和616.54、+/-163.15 um和1.87+/-0.10x10(-5)cm/S。在MDCKII-MDR1细胞中，依托泊苷的分泌通透性在基础到顶端(B到A)(即外排)方向显著降低，而在顶端到基础(A到B)方向的通透性增加2.3倍(GF120918)。白三烯C-4(LTC4)对MDCKII-cMOAT1细胞的依托泊苷外流有一定的抑制作用。此外，依托泊苷抑制了LTC4的外流，证实了cMOAT的参与。MDCKII-MRP1细胞中依托泊苷的通量与MDCKII/wt对照细胞相似。目前的结果表明，依托泊苷的分泌转运机制涉及多个转运体，包括PGP和cMOAT，但不涉及MRP1。这些结果表明，PGP和cMOAT参与了依托泊苷的肠道分泌转运。由于依托泊苷的肠道分泌已有文献报道，这也提示它们可能参与了依托泊苷在体内的肠道分泌；然而，还需要活体机制的研究来证实这一点。
Multidrug resistance conferred to cancer cells is often mediated by the expression of efflux transporter "pumps". It is also believed that many of the same transporters are involved in drug efflux from numerous normal endothelial and epithelial cell types in the intestine, brain, kidney, and liver. Etoposide transport kinetics were characterized in Caco-2 cells and in well established Madin-Darby canine kidney (MDCKII) cell lines that were stably-transfected with a human cDNA encoding P-glycoprotein (Pgp), human multidrug resistance protein (MRP1), or the canalicular multispecific organic anion (cMOAT) transporters to determine the roles of these transporters in etoposide efflux. Etoposide transport kinetics: were concentration-dependent in the MDCKII-MDR1 and MDCKII-cMOAT cells. The apparent secretory Michaelis constant (K-m) and carrier-mediated permeability (P-o) values for Pgp and cMOAT were 254.96 +/- 94.39 muM and 5.96 +/- 0.41 x 10(-6) cm/s and 616.54, +/- 163.15 muM and 1.87 +/- 0.10 x 10(-5) cm/s, respectively. The secretory permeability of etoposide decreased significantly in the basal to apical (B to A) (i.e., efflux) direction, whereas the permeability increased 2.3-fold in the apical to basal (A to B) direction in MDCKII-MDR1 cells in the presence of elacridar (GF120918). Moderate inhibition of etoposide efflux by leukotriene C-4 (LTC4) was observed in MDCKII-cMOAT1 cells. Furthermore, etoposide inhibited LTC4 efflux, confirming the involvement of cMOAT. The flux of etoposide in MDCKII-MRP1 cells was similar to that in MDCKII/wt control cells. The current results demonstrate that the secretory transport mechanism of etoposide involves multiple transporters, including Pgp and cMOAT but not MRP1. These results demonstrate that Pgp and cMOAT are involved in the intestinal secretory transport of etoposide. Since the intestinal secretion of etoposide was previously reported in the literature, it also suggests that they may be involved in the in vivo intestinal secretion of etoposide; however, mechanistic in vivo studies are required to confirm this.