Klein R S, Lenzi M, Lim T H, Hotchkiss K A, Wilson P, Schwartz E L
Department of Oncology, Albert Einstein Cancer Center, 111 East 210th St., Bronx, NY 10467, USA.
Biochem Pharmacol. 2001 Nov 1;62(9):1257-63. doi: 10.1016/s0006-2952(01)00783-3.
Thymidine phosphorylase (TP) catalyzes the reversible phosphorolysis of thymidine and other pyrimidine 2'-deoxyribonucleosides. In addition, TP has been shown to possess angiogenic activity in a number of in vitro and in vivo assays, and its angiogenic activity has been linked to its catalytic activity. A series of 5- and 6-substituted uracil derivatives were synthesized and evaluated for their abilities to inhibit TP activity. Among the most active compounds was a 6-amino-substituted uracil analog, 6-(2-aminoethyl)amino-5-chlorouracil (AEAC), which was a competitive inhibitor with a K(i) of 165 nM. The inhibitory activity of AEAC was selective for TP, as it did not inhibit purine nucleoside phosphorylase or uridine phosphorylase at concentrations up to 1 mM. Human recombinant TP induced human umbilical vein endothelial cell (HUVEC) migration in a modified Boyden chamber assay in vitro, and this action could be abrogated by the TP inhibitors. The actions of the inhibitors were specific for TP, as they had no effect on the chemotactic actions of vascular endothelial growth factor (VEGF). HUVEC migration was also induced when TP-transfected human colon and breast carcinoma cells were co-cultured in the Boyden chamber assay in place of the purified angiogenic factors, and a TP inhibitor blocked the tumor cell-mediated migration almost completely. These studies suggest that inhibitors of TP may be useful in pathological conditions that are dependent upon TP-driven angiogenesis.
胸苷磷酸化酶（TP）催化胸苷及其他嘧啶2'-脱氧核糖核苷的可逆磷酸解反应。此外，在多项体外和体内试验中，TP已被证明具有血管生成活性，其血管生成活性与其催化活性相关。合成了一系列5-和6-取代的尿嘧啶衍生物，并评估了它们抑制TP活性的能力。其中最具活性的化合物是一种6-氨基取代的尿嘧啶类似物，即6-(2-氨基乙基)氨基-5-氯尿嘧啶（AEAC），它是一种竞争性抑制剂，抑制常数（K(i)）为165 nM。AEAC的抑制活性对TP具有选择性，因为在浓度高达1 mM时，它不会抑制嘌呤核苷磷酸化酶或尿苷磷酸化酶。在体外改良的Boyden小室试验中，人重组TP可诱导人脐静脉内皮细胞（HUVEC）迁移，而这种作用可被TP抑制剂消除。这些抑制剂的作用对TP具有特异性，因为它们对血管内皮生长因子（VEGF）的趋化作用没有影响。在Boyden小室试验中，当用转染了TP的人结肠癌细胞和乳腺癌细胞共同培养来替代纯化的血管生成因子时，也可诱导HUVEC迁移，并且一种TP抑制剂几乎能完全阻断肿瘤细胞介导的迁移。这些研究表明，TP抑制剂可能对依赖TP驱动的血管生成的病理状况有用。
