5—FC对经基因修饰而表达胞嘧啶脱氨酶的哺乳类细胞杀伤作用

为获得５┐氟胞嘧啶（５┐ｆｌｕｏｒｏｃｙｔｏｓｉｎｅ，５┐ＦＣ）对含ＣＤ基因哺乳类细胞的“诱导”杀伤表型数据。方法小鼠成纤维细胞ＮＩＨ／３Ｔ３、大鼠神经胶质瘤细胞Ｃ６和包装细胞ＰＡ３１７，经基因修饰而表达非哺乳类酶－胞嘧啶脱氨酶（ｃｙ┐ｔｏｓｉｎｅｄｅａｍｉｎａｓｅ，ＣＤ）。结果体外，ＣＤ基因的表达几乎不影响细胞的生长速率。薄层层析分析（ＴＬＣ）表明，被含有重组逆转录病毒载体ｐＬＣＤＳＮ的假型病毒感染的哺乳类细胞及包装细胞的抽提液可将胞嘧啶代谢成脲嘧啶。５┐ＦＣ对有ＣＤ活性的细胞产生致死性细胞毒性。结论本实验支持了在５┐ＦＣ参与下，于肿瘤细胞内选择性表达ＣＤ的基因治疗方案。

LETHAL EFFECT OF 5 FC ON MAMMALIAN CELLS GENETICALLY MODIFIED TO EXPRESS CYTOSINE DEAMINASE

Objective:To obtain the lethal data of mammalian cells containing CD gene induced by 5 FC (5 fluorocytosine).Methods:A mouse fibroblast cell line NIH/3T3, a rat glioma cell line C6 and a packaging cell line PA317 were genetically engineered to express nonmammalian enzyme, cytosine deaminase(CD). Expression of CD in NIH/3T3, C6 and PA317 did not alter the growth rate of these cells in vitro.Results: The results of TLC assay indicated that the cell lysate of packaging cells and mammalian cells infected by pseudotype retrovirus with recombinant retroviral vector pLCDSN can convert cytosine into uracil.5 FC can induce the lethal cytotoxicity to cells with CD activity. Conclusions:These data support the continuing approach for gene therapy in which CD gene is expressed selectively with the presence of 5 FC.