Department of Pharmaceutics, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203, China.
Biomaterials. 2011 Mar;32(9):2399-406. doi: 10.1016/j.biomaterials.2010.11.079. Epub 2010 Dec 24.
Gene therapy offers great potential for brain glioma. However, therapeutic genes could not reach glioma spontaneously. A glioma-targeting gene delivery system is highly desired to transfer exogenous genes throughout the tumor focus. In this study, the nanoscopic high-branching dendrimer, polyamidoamine (PAMAM), was selected as the main vector. Chlorotoxin (CTX), which has been demonstrated to bind specifically to receptor expressed in glioma, was exploited as the targeting ligand to conjugate PAMAM via bifunctional polyethyleneglycol (PEG), yielding PAMAM-PEG-CTX. The cellular uptake of CTX itself was observed apparently in C6 glioma cells, almost not in 293 cells. The modification of CTX could significantly increase the cellular uptake of vectors and the DNA-loaded nanoparticles (NPs) in C6 cells. The in vivo distribution of PAMAM-PEG-CTX/DNA NPs in the brain was higher than that of PAMAM/DNA NPs and PAMAM-PEG/DNA NPs. Furthermore, the gene expression of PAMAM-PEG-CTX/DNA NPs was higher and broader in glioma than that of unmodified and PEG-modified counterparts. The TUNEL analysis showed a more wide-extended apoptosis in the CTX-modified group, compared to other groups including commercial temozolomide group. The median survival time of CTX-modified group and temozolomide group was 59.5 and 49 days, respectively, significantly longer than that of other groups. The results suggested that CTX could be exploited as a special glioma-targeting ligand, and PAMAM-PEG-CTX/DNA NPs is a potential non-viral delivery system for gene therapy of glioma via intravenous administration.
基因治疗为脑胶质瘤带来了巨大的潜力。然而，治疗性基因不能自发到达胶质瘤部位。因此，人们非常希望有一种能够靶向胶质瘤的基因传递系统，将外源性基因递送到肿瘤病灶。在这项研究中，纳米级高支化树状聚合物聚酰胺-胺（PAMAM）被选为主要载体。已经证实氯毒素（CTX）能够特异性结合胶质瘤中表达的受体，因此将 CTX 作为靶向配体，通过双功能聚乙二醇（PEG）与 PAMAM 偶联，得到 PAMAM-PEG-CTX。在 C6 胶质瘤细胞中观察到 CTX 本身的细胞摄取明显，而在 293 细胞中几乎没有。CTX 的修饰可以显著增加载体和载 DNA 的纳米粒（NPs）在 C6 细胞中的细胞摄取。PAMAM-PEG-CTX/DNA NPs 在脑中的分布高于 PAMAM/DNA NPs 和 PAMAM-PEG/DNA NPs。此外，PAMAM-PEG-CTX/DNA NPs 的基因表达在胶质瘤中比未修饰和 PEG 修饰的载体更高、更广泛。TUNEL 分析显示，与其他组（包括商业替莫唑胺组）相比，CTX 修饰组的凋亡更广泛。CTX 修饰组和替莫唑胺组的中位生存时间分别为 59.5 天和 49 天，明显长于其他组。结果表明，CTX 可作为一种特殊的胶质瘤靶向配体，PAMAM-PEG-CTX/DNA NPs 是一种潜在的非病毒基因传递系统，可通过静脉注射用于胶质瘤的基因治疗。
