光敏剂叶酸-卟啉对宫颈癌HeLa细胞的靶向性和光动力活性

目的评价光敏剂卟啉Ⅰ对宫颈癌HeLa细胞的肿瘤靶向性和光动力活性。方法采用荧光测定法和激光共聚焦扫描显微镜观察宫颈癌HeLa细胞对卟啉Ⅰ的吞噬作用;采用MTT试验观察卟啉Ⅰ在有或无光照条件下对人正常肝L-02细胞、肺腺癌A549细胞和宫颈癌HeLa细胞的生长抑制作用。结果孵育24 h后HeLa细胞对卟啉Ⅰ的吞噬量是前体卟啉A的35倍,且这种吞噬作用可被过量叶酸的加入明显抑制;卟啉Ⅰ对HeLa细胞呈现出很低的暗毒性和明显的光毒性,光照下在卟啉Ⅰ浓度为5.0×10-5mol/L时,HeLa细胞的生长抑制率达到84.6%;并且这种光毒性具有明显的叶酸受体阳性细胞选择性,在相同条件下,对正常L-02肝细胞和叶酸受体阴性A549细胞无光毒性。结论卟啉结构中引入叶酸单体后,由于叶酸受体的介导作用明显改善了该光敏剂的肿瘤靶向性和光动力活性。

Targeting and Photodynamic Activity of Folate-porphyrin Photosensitizer for Cervix Cancer HeLa Cells

Objective To evaluate the targeting and photodynamic activity of porphyrin Ⅰ for cervix cancer HeLa cells.Methods The cellular uptake of porphyrin Ⅰ by HeLa cells was tested by fluorescence spectroscopy and confocal laser scanning microscopy,the cytotoxicity of porphyrin Ⅰ against human normal liver L-02 cells,human alveolar basal epithelial A549 cells and human cervix cancer HeLa cells in vitro with or without folic acid were measured by MTT assay.Results The cellular uptake of porphyrin I by HeLa cells was 35 times higher than that of precursor porphyrin A after 24 h incubation,and the presence of excessive free folic acid inhibited obviously the cellular uptake of porphyrin Ⅰ.The results of MTT assay demonstrated that porphyrin Ⅰ exhibited much lower dark cytotoxicity but significant photocytotoxicity for HeLa cells,with 86.4% of cell growth inhibition ratio after irradiation at 5.0×10-5 mol/L concentration.And,porphyrin I displayed satisfactory selectivity for receptor positive cells.Under same condition,porphyrin Ⅰ induced very low photocytotoxicity for normal cells and receptor negative cells Conclusions These results suggest that the targeting and the photodynamic activity of porphyrin like photosensitizers be improved clearly due to the endocytosis mediated by folate-receptor after a folate block was linked to porphyrin.