【作者】 张伟； 郝俊国； 陈彦佐； 沙先谊； 方晓玲；

【Author】 ZHANG Wei, HAO Jun-guo, CHEN Yan-zuo, SHA Xian-yi, FANG Xiao-ling (School of pharmacy,Fudan University,Shanghai 201203,China)

【机构】 复旦大学药学院；

【摘要】 本文采用薄膜水化法制备了载紫杉醇(PTX)Pluronic P123/F127混合胶束(PF-PTX),并考察了其体外理化性质、细胞毒作用、逆转P-糖蛋白作用和机制、细胞摄取、细胞器共定位、细胞凋亡、细胞周期和体内药动学及药效学等特性。研究表明,该混合胶束粒径CMC值为0.0059%,粒径为25nm左右,包封率>90%,体外释放具有一定缓释作用,并且F127的引入显著地增强了体系的稳定性。另外,对于多药耐药(MDR)肿瘤细胞,PF-PTX的IC50值显著低于Taxol和PTX溶液;其细胞摄取和逆转P-糖蛋白作用均与CMC值相关,逆转特性可能与线粒体膜电势的变化和胞内ATP含量的减少有关;与Taxol相比,PF-PTX能更好地诱导细胞凋亡并将其捕获于G2/M期;共定位实验表明,PF-PTX主要存在于胞质的酸性囊泡中,未进入细胞核;体内实验表明,与Taxol相比,PF-PTX具有更好的长循环作用、更强的抗MDR肿瘤效应和更低的毒性。更多还原

【Abstract】 The aim of this work was to demonstrate the advantage of using paclitaxel (PTX)-loaded Pluronic P123/F127 mixed micelles (PF-PTX) to overcome multidrug resistance (MDR) in cancer compared to Taxol. PF-PTX was prepared by thin-film hydration method. The optimized formulation showed a particle size of about 25 nm with ER % > 90%, and a sustained release behavior compared to Taxol. The mixed micelles had a low CMC of 0.0059 % in DI water. In addition, micelle stability studies implied that introduction of Pluronic F127 (33 wt %) into P123 micelle system significantly increased the stability of PF-PTX. Moreover, in vitro cytotoxicity and cellular uptake of PF-PTX against MDR (NCI/ADR-RES and A-549) and sensitive (MCF-7) tumor cell lines were evaluated alongside Taxol. IC50 values were determined by the MTT assay, while cellular apoptosis was deteced by cell nuclei staining and Annexin V-FITC apoptosis detection kit. Cell cycle arrest was also confirmed by flow cytometry. In addition, in vivo fate and therapeutic effects of PF-PTX were extensively evaluated in comparison with Taxol. It was demonstrated that PF-PTX had superior anti-proliferation activity against the NCI/ADR-RES and A-549 cells compared with other PTX formulations as measured by IC50. Cellular uptake of PF-PTX was related to the CMC of block copolymers. The mechanisms of inhibition of P-gp were associated with the changed intra cellular ATP levels and mitochondrial potential. The hypersensitizing effect of Pluronic was associated with PTX-induced apoptosis and cell arrest in the G2/M phase. Most of the PF-PTX was localized to lysosomes, as evidenced by colocalization of green fluorescence with that from LysoTracker Red. PF-PTX exhibited significant advantages in vivo pharmacokinetics and biodistribution, and A-549 xenograft tumor model versus Taxol. The PF-PTX formulation achieved 3.0-fold longer mean residence time in circulation, 2.2-fold larger area under the plasma concentration-time curve than Taxol. At 28 days, tumor volume in PF-PTX group was only 31.8 % that of the Taxol. Therefore, PF-PTX significantly potentiates the anticancer activity of PTX and may be considered a promising drug delivery system to overcome MDR cancer.更多还原