Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, PR China.
Nanoscale. 2017 Jul 6;9(26):9190-9201. doi: 10.1039/c7nr02663c.
Chemotherapeutic drug resistance of tumor cells under hypoxic conditions is caused by the inhibition of apoptosis by autophagy and drug efflux via adenosine triphosphate (ATP)-dependent transporter activation, among other factors. Here, we demonstrate that disrupting glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression can reduce the autophagy and ATP levels in tumor cells. To test whether GAPDH knockdown is sufficient to overcome drug resistance, a nanocarrier (asymmetry-membrane liposome) was designed to encapsulate GAPDH-siRNA with a low dose of paclitaxel (PTX). Liposomes were prepared using novel cryogenic inner-outer dual reverse phase emulsion liposome manufacturing technology to obtain a high loading of siRNA. The results of dynamic light scattering (DLS) indicated that the liposomes had an average hydrodynamic diameter of 250.5 nm and polydispersity index (PDI) of 0.210, which was confirmed by (Transmission Electron Microscope) TEM images. In in vitro tests, the siRNA liposomes presented a high specificity in the suppression of GAPDH expression and significant synergy in cytotoxicity with co-delivery of PTX against tumor cells (HeLa and MCF-7) under hypoxic conditions. Moreover, in vivo studies (a HeLa tumor xenograft model using female BALB/c nude mice) demonstrate that the liposomes could not only increase the concentration of drugs in tumors over time but also successfully boosted the chemotherapeutic efficacy of PTX (synergistic therapy with GAPDH-siRNA). Tumor cells appeared to lose their resistance against PTX therapy, becoming more sensitive to PTX when GAPDH-siRNA was simultaneously administered in long-circulating liposomes. Consequently, the novel delivery of GAPDH-siRNA using nanotargeted liposomes provides a useful and potential tool to overcome multidrug resistant (MDR) tumors and presents a bright prospect compared with the traditional chemotherapeutic strategies in clinic cancer therapy.
肿瘤细胞在缺氧条件下的化疗药物耐药性是由自噬抑制细胞凋亡和通过三磷酸腺苷（ATP）依赖性转运体激活的药物外排等因素引起的。在这里，我们证明破坏甘油醛-3-磷酸脱氢酶（GAPDH）的表达可以降低肿瘤细胞中的自噬和 ATP 水平。为了测试 GAPDH 敲低是否足以克服耐药性，设计了一种纳米载体（不对称膜脂质体），用低剂量紫杉醇（PTX）包裹 GAPDH-siRNA。使用新型低温内外双重反相乳液脂质体制备技术制备脂质体，以获得高负载量的 siRNA。动态光散射（DLS）的结果表明，脂质体的平均水动力直径为 250.5nm，多分散指数（PDI）为 0.210，这通过透射电子显微镜（TEM）图像得到了证实。在体外试验中，siRNA 脂质体在抑制 GAPDH 表达方面具有很高的特异性，并且在缺氧条件下与 co-delivery 的 PTX 对肿瘤细胞（HeLa 和 MCF-7）的细胞毒性方面表现出显著的协同作用。此外，体内研究（使用雌性 BALB/c 裸鼠的 HeLa 肿瘤异种移植模型）表明，脂质体不仅可以随着时间的推移增加肿瘤中药物的浓度，而且还可以成功提高 PTX 的化疗疗效（与 GAPDH-siRNA 的协同治疗）。当同时给予长循环脂质体中的 GAPDH-siRNA 时，肿瘤细胞似乎失去了对 PTX 治疗的耐药性，对 PTX 变得更加敏感。因此，使用纳米靶向脂质体递送 GAPDH-siRNA 为克服多药耐药（MDR）肿瘤提供了一种有用且有潜力的工具，与传统的化疗策略相比，在临床癌症治疗中具有广阔的前景。
