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组织型纤溶酶原激活剂(t-PA)因其在防止血栓形成中起重要作用而受到人们的重视。但由于t-PA在血液中半衰期很短,作为溶栓药,一时难于推广。为了延长半衰期、增强其特异活性,本组构建了t-PA突变体并在CHO-dhfr~-细胞中获得了高效表达。我们在细胞培养基中加入秋水仙素,通过低张、固定、染色,进行染色体分析,结果表明,t-PA工程细胞系染色体条数为20条,畸变类型有异着丝粒。四倍体、裂隙、断片,畸变率为15％,属于正常范围。同时我们对该细胞系进行成瘤性试验,选用4周龄裸鼠作为试验鼠,以Hela细胞为阳性对照,CHO-dhfr~-细胞为阴性对照,试验表明:t-PA工程细胞及表达产物对裸鼠均无成瘤性。
Tissue-type plasminogen activator (t-PA) is valued for its important role in preventing thrombosis. However, due to the short half-life of t-PA in blood, it is difficult to promote it as a thrombolytic agent. In order to extend the half-life and enhance its specific activity, this group constructed a t-PA mutant and obtained high expression in CHO-dhfr ~ - cells. Colchicine was added to the cell culture medium. Chromosomal analysis was performed on low, fixed, and stained cells. The results showed that the number of chromosomes in t-PA engineering cell lines was 20, and the types of aberrations were allomorphic. Tetraploid, fissure, fragment, the distortion rate of 15%, belong to the normal range. At the same time, we carried out the tumorigenicity test to this cell line. 4-week-old nude mice were used as experimental mice, Hela cells as positive control and CHO-dhfr ~ - cells as negative control. The results showed that t-PA engineering cells and expression products No tumor formation in nude mice.