KIN-59 is a noncompetitive inhibitor against human and bacterial recombinant thymidine phosphorylase (TPase) with IC50 values of 67 and 44µM respectively[1]. KIN-59 is a purine riboside derivative that blocks the enzyme non-competitively with thymidine or phosphate, and requires both the intact 5′-O-trityl group and the ribose–hypoxanthine scaffold for activity[2].
In vitro, KIN-59 (0–100µM) incubated muse aortic endothelial cells (MAECs) for 5 days poorly inhibited cell proliferation with an IC50 value of 78 ± 2µM. KIN-59 also dose-dependently slowed endothelial cell migration in a 16-hour wound-healing assay[3]. KIN-59 (250nmol) incubated fertilized chicken eggs with or without 10µl of TPase for 4 days. KIN-59 not only annihilated the TPase-induced angiogenesis but also efficiently inhibited the formation of normal chick chorioallantoic membrane vessels in the absence of exogenously added TPase[4]. KIN-59 (125–250μM) pretreatment on human or wild-type murine platelets for 5min before collagen, ADP, thrombin or collagen related peptide stimulation reversibly and dose-dependently suppressed induced aggregation[5].
In vivo, KIN-59 (15mg/kg) was injected subcutaneously in immunodeficient nude mice twice daily (once daily during the weekend) until day 20. KIN-59 inhibited the binding of fibroblast growth factor 2 (FGF2) to FGF receptor 1, preventing the growth and neovascularization of subcutaneous tumors induced by FGF2-transformed endothelial cells[6].
References:
[1] Liekens S, Balzarini J, Hernández A I, et al. Thymidine phosphorylase is noncompetitively inhibited by 5'-O-trityl-inosine (KIN59) and related compounds. Nucleosides Nucleotides Nucleic Acids. 2006;25(9-11):975-80.
[2] Casanova E, Hernandez A I, Priego E M, et al. 5'-O-tritylinosine and analogues as allosteric inhibitors of human thymidine phosphorylase. J Med Chem. 2006 Sep 7;49(18):5562-70.
[3] Liekens, S., Bronckaers, A., Hernández, A.I., et al. 5'-O-tritylated nucleoside derivatives: inhibition of thymidine phosphorylase and angiogenesis. Mol. Pharmacol. 70(2), 501-509 (2006).
[4] Liekens, S., Hernández, A.I., Ribatti, D., et al. The nucleoside derivative 5'-O-trityl-inosine (KIN59) suppresses thymidine phosphorylase-triggered angiogenesis via a noncompetitive mechanism of action. The Journal of Biological Chemisty 279(28), 29598-29605 (2004).
[5] Li W, Gigante A, Perez-Perez M J, et al. Thymidine phosphorylase participates in platelet signaling and promotes thrombosis. Circ Res. 2014 Dec 5;115(12):997-1006.
[6] Liekens, S., Bronckaers, A., Belleri, M., et al. The thymidine phosphorylase inhibitor 5'-O-tritylinosine (KIN-59) is an antiangiogenic multitarget fibroblast growth factor-2 antagonist. Mol. Cancer Ther. 11(4), 817-829 (2012).
KIN-59是针对人源和细菌重组胸苷磷酸化酶（TPase）的非竞争性抑制剂，IC50值分别为67和44µM[1]。KIN-59是一种嘌呤核糖衍生物，能以非竞争性方式阻断酶与胸苷或磷酸的结合，其活性依赖于完整的5′-O-三苯甲基和核糖-次黄嘌呤骨架[2]。
体外实验中，KIN-59（0–100µM）孵育小鼠主动脉内皮细胞（MAECs）5天，对细胞增殖的抑制作用较弱，IC50值为78 ± 2µM。KIN-59在16小时划痕愈合实验中也呈剂量依赖性地减缓内皮细胞迁移[3]。KIN-59（250nmol）单独或与10µl TPase共同孵育受精鸡蛋4天，KIN-59不仅消除了TPase诱导的血管生成，还有效抑制了无外源TPase存在时正常鸡胚绒毛尿囊膜血管的形成[4]。KIN-59（125–250µM）在人或野生型小鼠血小板中加入胶原、ADP、凝血酶或胶原相关肽前预处理5分钟。KIN-59可逆且呈剂量依赖性地抑制诱导的血小板聚集[5]。
体内实验中，KIN-59（15mg/kg）通过皮下注射免疫缺陷裸鼠，每日两次（周末每日一次），持续至第20天。KIN-59抑制成纤维细胞生长因子2（FGF2）与FGF受体1的结合，阻止由FGF2转化的内皮细胞诱导的皮下肿瘤生长和新生血管形成[6]。