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

除长春花生物碱和紫杉烷外，所有经典的抗肿瘤药物都对细胞中的DNA代谢起作用，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代谢的各种活动。胸腺苷酸合成酶（TS）调控胸腺苷酸合成的限制步骤，作为细胞对最广泛使用的抗癌药物5-氟尿嘧啶（5-FU）敏感性的决定因素，一直受到关注。然而，迄今为止，这种可能性是通过回顾性的，即归纳的方法研究的，除了少数例外，尚未得出结论。为了先验地解决这一问题，将ts表达质粒载体导入人结直肠癌细胞系DLD-1。在该系统中，TS转基因的表达受四环素依赖启动子的控制，并通过耗尽培养基中的抗生素诱导。分离了10个表达ts的转化子，并建立了一个细胞系。其中，TS表达的动态范围超过10倍。利用这种转化细胞系，目前正在从不同角度探讨不同水平TS表达下5-FU的敏感性。

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.