Sen Joyeeta, Chaudhuri Arabinda
Division of Lipid Science and Technology, Indian Institute of Chemical Technology, Hyderabad-500 007, India.
Bioconjug Chem. 2005 Jul-Aug;16(4):903-12. doi: 10.1021/bc0500443.
Herein, we report on the relative in vitro efficacies of nine novel non-glycerol based cationic amphiphiles with increasing hydrophobic tails and the amino acids serine, alanine and beta-alanine as the headgroup functionalities (lipids 1-9, Scheme 1) in transfecting multiple cultured cells including CHO, COS-1, MCF-7, and HepG2. The gene transfer efficiencies of lipids 1-9 were evaluated using the reporter gene assays in all the four cell lines and the whole cell histochemical X-gal staining assays in representative CHO cells. In CHO, HepG2, and MCF-7 cells, cationic lipids with alanine (4-6) and beta-alanine (7-9) headgroups were found to be remarkably more transfection efficient than their serine headgroup counterparts (1-3). Most notably, in CHO, HepG2, and MCF-7 cells, in combination with cholesterol as auxiliary lipid, the transfection efficiencies of the cationic lipids with alanine and beta-alanine headgroups and myristyl and palmityl tails (lipids 4, 5, 7 and 8) were significantly higher (2-3-fold) than that of LipofectAmine-2000, a widely used commercially available liposomal tranfection vectors. Surprisingly, in COS-1 cells, although cationic lipids with beta-alanine headgroups (7-9) were strikingly transfection efficient (3-4-fold more efficacious than LipofectAmine-2000), the gene transfer properties of both their structural isomers (4-6) and their serine headgroup counterparts (1-3) were adversely affected. In summary, the present structure-activity investigation demonstrate that high gene delivery efficacies of cationic amphiphiles containing alanine or beta-alanine headgroups can get seriously compromised by substituting the alanine or beta-alanine with serine presumably due to the enhanced sensitivity of DNA associated with such serine-head-containing cationic lipids.
在此，我们报告了九种新型非甘油基阳离子两亲物的相对体外转染效率，这些两亲物具有逐渐增加的疏水尾以及作为头部基团功能的氨基酸丝氨酸、丙氨酸和β-丙氨酸（脂质1-9，方案1），用于转染包括CHO、COS-1、MCF-7和HepG2在内的多种培养细胞。使用报告基因检测法在所有四种细胞系中评估脂质1-9的基因转移效率，并在代表性的CHO细胞中使用全细胞组织化学X-gal染色检测法进行评估。在CHO、HepG2和MCF-7细胞中，发现具有丙氨酸（4-6）和β-丙氨酸（7-9）头部基团的阳离子脂质比其丝氨酸头部基团对应物（1-3）的转染效率显著更高。最值得注意的是，在CHO、HepG2和MCF-7细胞中，与胆固醇作为辅助脂质结合时，具有丙氨酸和β-丙氨酸头部基团以及肉豆蔻基和棕榈酰基尾部的阳离子脂质（脂质4、5、7和8）的转染效率比广泛使用的市售脂质体转染载体LipofectAmine-2000显著更高（2-3倍）。令人惊讶的是，在COS-1细胞中，尽管具有β-丙氨酸头部基团的阳离子脂质（7-9）具有显著的转染效率（比LipofectAmine-2000高3-4倍），但其结构异构体（4-6）及其丝氨酸头部基团对应物（1-3）的基因转移特性均受到不利影响。总之，目前的构效关系研究表明，含有丙氨酸或β-丙氨酸头部基团的阳离子两亲物的高基因递送效率可能会因用丝氨酸取代丙氨酸或β-丙氨酸而受到严重损害，这可能是由于与这种含丝氨酸头部的阳离子脂质相关的DNA敏感性增强所致。
