The improvement of therapeutic efficacy for cancer agents has been a big challenge which includes the increase of tumor selectivity and the reduction of adverse effects at non-tumor sites. In order to achieve those goals, prodrug approaches have been extensively investigated. In this report, the potential activation enzymes for 5¢-amino acid/dipeptide monoester floxuridine prodrugs in pancreatic cancer cells were selected and the feasibility of enzyme specific activation of prodrugs was evaluated. All prodrugs exhibited the range of 3.0–105.7 min of half life in Capan-2 cell homogenate with the presence and the absence of selective enzyme inhibitors. 5¢-O-L-Phenylalanyl-L-tyrosyl-floxuridine exhibited longer half life only with the presence of pepstatin A. Human cathepsin B and D selectively hydrolized 5¢-O-L-phenylalanyl-L-tyrosylfloxuridine and 5¢-O-L-phenylalanyl-L-glycylfloxuridine compared to the other tested prodrugs. The wide range of growth inhibitory effect by floxuridine prodrugs in Capan-2 cells was observed due to the different affinities of prodrug promoieties to enyzmes. In conclusion, it is feasible to design prodrugs which are activated by specific enzymes. Cathepsin D might be a good candidate as a target enzyme for prodrug activation and 5¢-O-L-phenylalanyl-L-tyrosylfloxuridine may be the best candidate among the tested floxuridine prodrugs.
提高抗癌药物的疗效一直是一个巨大的挑战,其中包括提高肿瘤选择性和减少非肿瘤部位的不良反应。为了实现这些目标,人们对原药方法进行了广泛的研究。本报告选择了 5'-
氨基酸/二肽单酯
氟尿
嘧啶原药在胰腺癌细胞中的潜在活化酶,并评估了酶特异性活化原药的可行性。在存在或不存在选择性酶
抑制剂的情况下,所有原药在 Capan-2 细胞匀浆中的半衰期范围为 3.0-105.7 分钟。与其他测试的原药相比,5'-O-L-苯丙
氨酰-L-酪
氨酰-
氟尿苷和 5'-O-L-苯丙
氨酰-L-甘
氨酰-
氟尿苷能被人类
酪蛋白酶 B 和 D 选择性地
水解。在 Capan-2 细胞中观察到的
氟尿
嘧啶原药的生长抑制作用范围很广,这是因为原药原基与酶的亲和力不同。总之,设计能被特定酶激活的原药是可行的。Cathepsin D 可能是原药活化的候选靶酶,而 5¢-O-L-phenylalanyl-L-tyrosylfloxuridine 可能是所测试的
氟尿
嘧啶原药中的最佳候选酶。