光化学作用增强阳离子聚合物介导EGFP转染结肠癌

Photochemical effect increases gene transfection of EGFP plasmids mediated by polycation

目的观察光化学基因转染技术对阳离子聚合物介导目的DNA转染结肠癌细胞效率的影响。方法以结肠癌细胞SW 480、HT29为靶细胞,激光共聚焦显微镜观察光敏剂TPPS2 a的胞内分布,MTT法观察基于TPPS2 a的光化学作用对结肠癌细胞的生长抑制作用,同时以阳离子聚合物PEI为DNA载体,EGFP质粒为目的DNA,通过流式细胞技术对比观察光化学作用对阳离子聚合物介导EGFP质粒转染结肠癌细胞的影响。结果TPPS2 a在2种结肠癌细胞系呈颗粒状分布于细胞质;基于TPPS2 a的光动力效应对结肠癌细胞的生长抑制作用随光照剂量增大而逐渐加大,SW 480细胞取得IC50的光照时间为约6 m in,而HT29取得IC50的光照时间为约12 m in;与单纯质粒转染组和阳离子聚合物转染组相比,光化学作用可将阳性细胞率分别提高至(29.61±1.15)(SW 480细胞)和(23.47±0.62)(HT29细胞)(P<0.05)。结论TPPS2 a的胞内分布与内吞密切相关;基于TPPS2 a的光化学细胞毒性作用呈剂量依赖性;与单纯质粒转染组和阳离子聚合物转染组相比,光化学作用可明显提高阳离子聚合物介导转染目的DNA的阳性细胞率。

Objective To investigate the effect of photochemical gene transfection on colon cancer cells mediated by polycation. Methods Based on SW480 and HT29 colon carcinoma cell culture, the intracellular localization of meso-tetraphenylporphine disulfonate （TPPS2.） were observed by laser confocal scanning microscopy （LCSM）. Photochemically induced cytotoxicity of TPPS2. on SW480 and HT29 cell lines was evaluated by MTT assay. By flow cytometry, the light-induced transfection of EGFP plasmids mediated by PEI was studied. Results TPPS2a exhibited typical vesicular localization in two colon carcinoma cell lines. The photochemical cytotoxicity based on TPPS2a increased with light dose. The light dose of ICso was 22 mW/cm^2 for 6 min for SW480 cells and for 12 min for HT29 ceils （wavelength： 405 nm）. The light treatment based on TPPS2a induced an increase in transfection efficiency to （29.61 ± 1.15） for SW480 cells and （23.47 ±0.62） for H129 cells （P 〈0. 05） as compared with that of other groups. Conclusion Endocytosis is involved in intracellular localization of TPPS2a. The inhibition of photochemical cytotoxicity based on TPPS2, depends on the light dose. Photochemical effect could significantly increase the transfection efficiency of target DNA mediated by polycation.