光化学作用对肿瘤细胞胞吞大分子的释放

Release of Endocytic Macromolecules by Photochemical Reaction

目的观察不同光敏剂在肿瘤细胞内的分布,以及光化学作用对肿瘤细胞胞吞大分子的释放作用。方法使用激光共聚焦显微镜观察ALA、ALAHE、HMME、TPPSa2在肿瘤细胞SW480、K562的胞内分布,使用FITC右旋糖酐观察肿瘤细胞对荧光标记大分子的胞吞作用,通过光照激发光敏化细胞,动态观察光化学作用前后胞吞大分子FITC右旋糖酐的胞内分布变化。结果ALA、ALAHE、HMME、TPPSa24种光敏剂均表现为胞质分布,核内分布少。ALA、ALAHE的胞内分布主要表现为胞质内的弥散性荧光。HMME则表现为胞质内颗粒状荧光与弥散荧光同时存在。TPPSa2为典型的胞质内颗粒状荧光分布。光敏剂在SW480、K562两种肿瘤细胞的胞内分布没有明显差异。光照激发不同光敏剂对肿瘤细胞胞吞FITC左旋糖酐的胞内分布影响不同。由TPPSa2及HMME活化而产生的光化学作用表现出明显的荧光颗粒重分布,ALA、ALAHE则对胞吞荧光无明显重分布作用。结论不同光敏剂因其不同的理化性质而表现为不同的胞内分布。光化学作用可对肿瘤细胞胞吞大分子产生胞吞释放作用,其作用机制可能与光化学作用对胞吞泡的破坏有关。

Objective To investigate the intracellular localization of different photosensitizers and to observe release of macromolecules by photochemical reaction. Methods The intracellular localization of photosensitizers ALA,ALA-HE,HMME,and TPPS_ a2 in colon adenocarcinoma cells SW480 and erythrocytic leukemic cells K562 was observed with laser confocal scanning microscopy.The effect of photochemical reaction on the intracellular localization of endocytic macromolecules was investigated by using endocytic marker FITC-dextran. Results Four photosensitizers showed cytosol localization.ALA(or ALA-HE)-induced protoporphyrinⅨ(PpⅨ) was diffusely located all over the cytosol .While TPPS_ a2 exhibited typical vesicular localization. The diffuse and granular fluorescence indicated HMME had complicated pattern of intracellular localization.There was no obvious difference in localization between two cell lines.After light-activation, TPPS_ a2 and HMME had obvious effect on cytosol relocalization of endocytic marker FITC-dextran,while ALA and ALA-HE had negative effect on it. Conclusions Depending on different physicochemical properties,various photosensitizers have different intracellular localization.Photochemical reaction based on endocytic photosensitizers could induce the cytosol relocalization of endocytic macromolecules.