School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin 2, Ireland.
Eur J Pharm Biopharm. 2011 Apr;77(3):392-7. doi: 10.1016/j.ejpb.2010.11.009. Epub 2010 Nov 18.
P-glycoprotein/MDR1 (P-gp) is a well-characterised membrane transporter relevant in drug disposition and multi-drug resistance. In this study, we aimed to investigate how far nanoparticulates impair the function of the P-gp transport system and which particle properties govern these interactions. Expression and function of P-gp was confirmed in A549 cell monolayers. Rhodamine 123 (Rh123) release studies were carried out in the presence of known inhibitors of P-gp function (i.e., cyclosporine A and verapamil), under ATP depletion (NaN(3)/DOG) and after acute exposure to nanoparticles (NPs) with different surface modifications, ζ-potentials and sizes (plain, carboxylated, and amine- and sulphate-modified). The cytotoxic potential of NPs on A549 monolayers was evaluated by MTT assay. The effects on P-gp protein level, after incubation with NPs, were investigated by Western blot analysis of A549 cell lysate and supernatant. Cellular retention of Rh123 was significantly (P<0.05) increased in the presence of carboxylated (100 nm), amine- and sulphate-modified NPs. A slight, but not significant, decrease in Rh123 release was also observed for plain latex and carboxylated (500 nm) NPs. The MTT assay demonstrated that most NPs caused only marginal levels of cytotoxicity (78-88% cell viability); the positively charged amine-NPs, however, were considerably more cytotoxic. Western blot showed that NPs did not cause any cell membrane disruption. Our findings suggest that nanomaterials can attenuate membrane transporter function depending on their size and surface properties and hence might influence the disposition of xenobiotics as well as endogenous substrates.
P-糖蛋白/MDR1（P-gp）是一种特征明确的膜转运蛋白，与药物处置和多药耐药性有关。在这项研究中，我们旨在研究纳米颗粒在多大程度上损害了 P-gp 转运系统的功能，以及哪些颗粒特性控制着这些相互作用。在 A549 细胞单层中证实了 P-gp 的表达和功能。在存在已知的 P-gp 功能抑制剂（即环孢菌素 A 和维拉帕米）的情况下，进行罗丹明 123（Rh123）释放研究，在 ATP 耗竭（NaN3 / DOG）下，以及在急性暴露于具有不同表面修饰、ζ-电位和粒径（普通、羧基化、胺化和硫酸盐化）的纳米颗粒后。通过 MTT 测定评估 NPs 对 A549 单层的细胞毒性潜力。通过 Western blot 分析 A549 细胞裂解物和上清液，研究与 NPs 孵育后 P-gp 蛋白水平的变化。在羧基化（100nm）、胺化和硫酸盐化 NPs 的存在下，Rh123 的细胞内保留显著增加（P<0.05）。普通胶乳和羧基化（500nm）NPs 的 Rh123 释放也略有下降，但无统计学意义。MTT 测定表明，大多数 NPs 仅引起轻微的细胞毒性（78-88%细胞活力）；然而，带正电荷的胺-NPs 则具有相当大的细胞毒性。Western blot 显示 NPs 不会引起任何细胞膜破裂。我们的研究结果表明，纳米材料可以根据其大小和表面特性来减弱膜转运蛋白的功能，从而可能影响外源性物质以及内源性底物的处置。
