Preparation of a TK/GCV administration system mediated by transferrin modified pro-cationic liposomes
作者:Zhong, Zhi-Rong、Zhang, Zhi-Rong、Deng, Yong、Liu, Ji、Song, Qing-Guo、Liu, Jie、He, Qin
DOI:10.1691/ph.2007.7.6248
日期:——
Transferrin modified pro-cationic liposomes were prepared and used to investigate the effect of targeting therapeutic genes to human hepatoma carcinoma cells in vitro. The main lipid CHETA, cholest-5-en-3β-yl[2-[[4-[(carboxymethyl)dithio]-1-iminobutyl]amino]ethyl] carbamate (C36H61N3O4S2), was synthesized and used to prepare pro-cationic liposomes. The thymidine kinase (TK) gene loaded pro-cationic liposomes were prepared by first mixing the plasmid DNA and protamine together, and then incubating the resulted polyplexes with blank pro-cationic liposomes preformed by the thin film dispersion-sonication method. Transferrin (Tf) was adsorbed on the surface of pro-cationic liposomes via electrostatic interactions to form transferrin modified pro-cationic liposomes. Cellular association was measured by fluorimetry at excitation and emission wavelengths of 490 and 520 nm, respectively. The viability of TK gene infected cells following administration of ganciclovir (GCV) was investigated by MTT assay. The transferrin modified TK gene pro-cationic liposomes had a mean diameter of 240 ± 12 nm and zeta potential of –24.10 ± 2.5 mV (n = 3). The transmission electron microscopy image indicated that most of the liposomes were relatively regular and spherical with a condensed core inside. Cell-associated fluorescence of Tf-liposomes and unmodified liposomes (without transferrin) was 7.8 × 106, and 3.2 × 106 per milligram protein, respectively. Compared to LipofectamineTM 2000 (Invitrogen, USA) the pro-cationic liposomes and transferrin modified pro-cationic liposomes had less cytotoxicity to cells. The transduced TK gene HepG2 cells were more sensitive to GCV than the un-transduced TK gene ones and the human normal Chang liver cells were not affected by the TK/GCV system mediated by procationic liposomes.
转铁蛋白修饰的前阳离子脂质体被制备并用于研究靶向治疗基因对人肝肿瘤细胞的体外效果。主要脂质CHETA、胆固醇-5-烯-3β-基[2-[[4-[(羧甲基)二硫]-1-亚氨基丁基]氨基]乙基]氨基甲酸酯(C36H61N3O4S2)被合成并用于制备前阳离子脂质体。负载胸苷激酶(TK)基因的前阳离子脂质体是通过将质粒DNA与鱼精蛋白混合后,孵育得到的聚复合物与通过薄膜分散-超声法预先形成的空白前阳离子脂质体。转铁蛋白(Tf)通过静电相互作用被吸附在前阳离子脂质体的表面,从而形成转铁蛋白修饰的前阳离子脂质体。细胞结合量通过在490和520 nm的激发和发射波长下进行荧光测定来测量。通过MTT法研究了在施用更昔洛韦(GCV)后,TK基因感染细胞的存活率。转铁蛋白修饰的TK基因前阳离子脂质体的平均直径为240 ± 12 nm,zeta电位为–24.10 ± 2.5 mV(n = 3)。透射电子显微镜图像显示,大多数脂质体相对规则且呈球形,内部有致密的核心。Tf-脂质体和未修饰脂质体(未含转铁蛋白)的细胞结合荧光分别为7.8 × 106和3.2 × 106每毫克蛋白。与LipofectamineTM 2000(Invitrogen, USA)相比,前阳离子脂质体和转铁蛋白修饰的前阳离子脂质体对细胞的细胞毒性较低。转导的TK基因HepG2细胞对GCV的敏感性高于未转导的TK基因细胞,而人正常Chang肝细胞则未受到前阳离子脂质体介导的TK/GCV系统的影响。