小干扰RNA-紫杉醇固体脂质纳米粒克服肿瘤多药耐药性的体外细胞学研究

Cytological Study in vitro on Co-delivery of siRNA and Paclitaxel within Solid Lipid Nanoparticles to Overcome Multidrug Resistance in Tumors

肿瘤多药耐药性(MDR)是临床上肿瘤化疗失败的主要原因,其中由多药耐药基因(MDR1)编码的P-糖蛋白(P-gp)又在MDR发生机制中占重要作用。本实验设计合成特异性沉默MDR1基因的小干扰RNA(siRNA),协同抗肿瘤药物紫杉醇(PTX)共同包裹于固体脂质纳米粒(SLNs)中,利用基因治疗和化学治疗的协同作用,以期克服肿瘤多药耐药性。实验包括制备siRNA-紫杉醇固体脂质纳米粒(siRNA-PTX-SLNs);检测载药SLNs对肿瘤细胞的增殖抑制作用;测定给药后PTX的细胞摄取率;采用实时荧光定量PCR和流式细胞法评价siRNA-PTX-SLNs对MDR1表达的沉默作用。结果显示在耐药细胞MCF-7/ADR中siRNA-PTX-SLNs能够显著提高PTX细胞摄取率,有效沉默MDR1的表达,抑制P-gp的外排作用,促进P-gp底物在细胞的蓄积。因此siRNA-PTX-SLNs可发挥克服肿瘤多药耐药性的协同治疗作用。

Multidrug resistance（MDR）remains the major obstacle to the success of clinical cancer chemotherapy.Pglycoprotein（P-gp）,encoded by the MDR1,is an important part with complex mechanisms associated with the MDR.In order to overcome the MDR of tumors,we in the present experimental design incorporated small interfering RNA（siRNA）targeting MDR1 gene and anticancer drug paclitaxel（PTX）into the solid lipid nanoparticles（SLNs）to achieve the combinational therapeutic effects of genetherapy and chemotherapy.In this study,siRNA-PTX-SLNs were successfully prepared.The cytotoxicity of blank SLNs and siRNA-PTX-SLNs in MCF-7cells and MCF-7/ADR cells were detected by MTT;and the uptake efficiency of PTX in MCF-7/ADR cells were detected via HPLC method;quantitative real-time PCR and flow cytometry were performed to investigate the silencing effect of siRNA-PTXSLNs on MDR1 gene in MCF-7/ADR cells.The results showed that PTX loaded SLNs could significantly inhibit the growth of tumor cells,and more importantly,the MDR tumor cells treated with siRNA-PTX-SLNs showed the lowest viability.HPLC study showed that SLNs could enhance the cellular uptake for PTX.Meanwhile,siRNA delivered by SLNs significantly decreased the P-gp expression in MDR tumor cells,thus increased the cellular accumulation of rhodamine123 as a P-gp substrate.In conclusion,the MDR1 gene could be silenced by siRNA-PTX-SLNs,which could promote the growth inhibition efficiency of PTX on tumor cells,leading to synergetic effect on MDR tumor therapy.