Identification of biomarkers to predict anticancer drug sensitivities by means of transgene experiments

除了长春花生物碱和紫杉烷之外，所有经典的抗肿瘤药物都作用于细胞中的DNA代谢，因此可以归类为“DNA代谢抑制剂”。细胞对这些药物的敏感性很大程度上取决于DNA代谢中的各种活动。胸苷酸合成酶（TS）调节胸苷酸合成的限制步骤，长期以来一直受到关注，作为细胞对最广泛使用的抗癌剂5-氟尿嘧啶（5-FU）的敏感性的决定因素。然而，迄今为止，这种可能性是通过回顾性即归纳性的方法进行研究的，只有少数例外，而且尚未得出结论。为了解决这个问题的先验，TS-表达质粒载体已被引入到人结肠直肠癌细胞系，DLD-1。在该系统中，TS转基因的表达在四环素依赖性启动子的控制下，并通过培养基中抗生素的消耗来诱导。分离10个TS表达转化体并建立为细胞系。在一个中，TS表达的动态范围超过十倍。使用这种细胞系，5-FU敏感性在不同水平的TS表达，现在正在接近从不同的角度。

All of the classical antineplastic agents, with the exception of vinca alkaloids and taxanes, work on DNA metabolism in cells and can therefore be categorised as 'DNA metabolism inhibitor'. Cellular sensitivity against these drugs largely depends on various activities in DNA metabolism. Thymidylate synthase (TS), which regulate the limiting step of thymidylate synthesis, has long received attention as a determinant of cellular sensitivity against the most widely used anticancer agent, 5-fluorouracil (5-FU). However, this possibility has thus far been studied by retrospective, i.e. inductive, approaches, with few exceptions, and has not been concluded yet. In order to approach this problem a priori, a TS-expression plasmid vector has been introduced into a human colorectal cancer cell line, DLD-1. In this system, the expression of the TS transgene is under the control of tetracycline-dependent promoter and inducible by depletion of the antibiotics in the culture media. Ten TS-expressing transformants were isolated and established as a cellline. In one, the dynamic range of TS expression was over ten-fold. Using this transformant cell line, the 5-FU sensitivity at diverse levels of TS expression are now being approached from various angles.