Chavanpatil Mahesh D, Khdair Ayman, Gerard Brigitte, Bachmeier Corbin, Miller Donald W, Shekhar Malathy P V, Panyam Jayanth
Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA.
Mol Pharm. 2007 Sep-Oct;4(5):730-8. doi: 10.1021/mp070024d. Epub 2007 Aug 18.
Nanoparticles enhance the therapeutic efficacy of an encapsulated drug by increasing and sustaining the delivery of the drug inside the cell. We have previously demonstrated that Aerosol OT (AOT)-alginate nanoparticles, a novel formulation developed recently in our laboratory, significantly enhance the therapeutic efficacy of encapsulated drugs like doxorubicin in drug-sensitive tumor cells. The purpose of this study is to evaluate the drug delivery potential of AOT-alginate nanoparticles in drug-resistant cells overexpressing the drug efflux transporter, P-glycoprotein (P-gp). AOT-alginate nanoparticles were formulated using an emulsion-cross-linking process. Rhodamine 123 and doxorubicin were used as model P-gp substrates. Cytotoxicity of nanoparticle-encapsulated doxorubicin and kinetics of nanoparticle-mediated cellular drug delivery were evaluated in both drug-sensitive and -resistant cell lines. AOT-alginate nanoparticles enhanced the cytotoxicity of doxorubicin significantly in drug-resistant cells. The enhancement in cytotoxicity with nanoparticles was sustained over a period of 10 days. Uptake studies with rhodamine-loaded nanoparticles indicated that nanoparticles significantly increased the level of drug accumulation in resistant cells at nanoparticle doses higher than 200 microg/mL. Blank nanoparticles also improved rhodamine accumulation in drug-resistant cells in a dose-dependent manner. Nanoparticle-mediated enhancement in rhodamine accumulation was not because of membrane permeabilization. Fluorescence microscopy studies demonstrated that nanoparticle-encapsulated doxorubicin was predominantly localized in the perinuclear vesicles and to a lesser extent in the nucleus, whereas free doxorubicin accumulated mainly in peripheral endocytic vesicles. Inhibition of P-gp-mediated rhodamine efflux with AOT-alginate nanoparticles was confirmed in primary brain microvessel endothelial cells. In conclusion, an AOT-alginate nanoparticle system enhanced the cellular delivery and therapeutic efficacy of P-gp substrates in P-gp-overexpressing cells.
纳米颗粒通过增加并维持细胞内药物递送，提高了被包裹药物的治疗效果。我们之前已经证明，气溶胶OT（AOT）-海藻酸盐纳米颗粒是我们实验室最近开发的一种新型制剂，它能显著提高阿霉素等被包裹药物在药物敏感肿瘤细胞中的治疗效果。本研究的目的是评估AOT-海藻酸盐纳米颗粒在过表达药物外排转运蛋白P-糖蛋白（P-gp）的耐药细胞中的药物递送潜力。AOT-海藻酸盐纳米颗粒采用乳液交联法制备。罗丹明123和阿霉素用作P-gp底物模型。在药物敏感和耐药细胞系中评估了纳米颗粒包裹的阿霉素的细胞毒性以及纳米颗粒介导的细胞药物递送动力学。AOT-海藻酸盐纳米颗粒在耐药细胞中显著增强了阿霉素的细胞毒性。纳米颗粒对细胞毒性的增强作用持续了10天。对负载罗丹明的纳米颗粒的摄取研究表明，在纳米颗粒剂量高于200μg/mL时，纳米颗粒显著提高了耐药细胞中的药物积累水平。空白纳米颗粒也以剂量依赖的方式改善了耐药细胞中罗丹明的积累。纳米颗粒介导的罗丹明积累增强并非由于膜通透性增加。荧光显微镜研究表明，纳米颗粒包裹的阿霉素主要定位于核周囊泡，较少程度定位于细胞核，而游离阿霉素主要积累在外周内吞囊泡中。在原代脑微血管内皮细胞中证实了AOT-海藻酸盐纳米颗粒对P-gp介导的罗丹明外排的抑制作用。总之，AOT-海藻酸盐纳米颗粒系统增强了P-gp过表达细胞中P-gp底物的细胞递送和治疗效果。
