Identification of a Potent and Selective Pharmacophore for Cdc25 Dual Specificity Phosphatase Inhibitors.
作者:John S. Lazo、Kaoru Nemoto、Katharine E. Pestell、Kathleen Cooley、Eileen C. Southwick、Douglas A. Mitchell、William Furey、Rick Gussio、Daniel W. Zaharevitz、Beomjun Joo、Peter Wipf
DOI:10.1124/mol.61.4.720
日期:2002.4.1
Small molecules provide powerful tools to interrogate biological pathways but many important pathway participants remain refractory to inhibitors. For example, Cdc25 dual-specificity phosphatases regulate mammalian cell cycle progression and are implicated in oncogenesis, but potent and selective inhibitors are lacking for this enzyme class. Thus, we evaluated 10,070 compounds in a publicly available chemical repository of the National Cancer Institute for in vitro inhibitory activity against oncogenic, full-length, recombinant human Cdc25B. Twenty-one compounds had mean inhibitory concentrations of <1 μM; >75% were quinones and >40% were of the para -naphthoquinone structural type. Most notable was NSC 95397 (2,3-bis-[2-hydroxyethylsulfanyl]-[1,4]naphthoquinone), which displayed mixed inhibition kinetics with in vitro K i values for Cdc25A, -B, and -C of 32, 96, and 40 nM, respectively. NSC 95397 was more potent than any inhibitor of dual specificity phosphatases described previously and 125- to 180-fold more selective for Cdc25A than VH1-related dual-specificity phosphatase or protein tyrosine phosphatase 1b, respectively. Modification of the bis -thioethanol moiety markedly decreased enzyme inhibitory activity, indicating its importance for bioactivity. NSC 95397 showed significant growth inhibition against human and murine carcinoma cells and blocked G2/M phase transition. A potential Cdc25 site of interaction was postulated based on molecular modeling with these quinones. We propose that inhibitors based on this chemical structure could serve as useful tools to probe the biological function of Cdc25.
小分子为研究生物通路提供了强大的工具,但许多重要的通路参与者对抑制剂仍然不敏感。例如,Cdc25双特异性磷酸酶调控哺乳动物细胞周期进程,并与肿瘤发生有关,但这一酶类缺乏强效且选择性的抑制剂。因此,我们在国家癌症研究所的一个公开化学文库中评估了10,070种化合物对致癌全长重组人Cdc25B的体外抑制活性。21种化合物的平均抑制浓度均<1μM;其中>75%为醌类,>40%为对硅醌结构类型。最引人注目的是NSC 95397(2,3-双[2-羟基乙基硫基]-[1,4]硅醌),它显示出混合抑制动力学,Cdc25A、-B和-C的体外K i值分别为32、96和40 nM。NSC 95397的抑制活性超过了以往描述的任何双特异性磷酸酶抑制剂,对Cdc25A的选择性比VH1相关的双特异性磷酸酶或蛋白酪氨酸磷酸酶1b高125到180倍。对双硫乙醇基团的修饰显著降低了酶的抑制活性,表明其对生物活性的重要性。NSC 95397对人源和小鼠癌细胞显示出显著的生长抑制,并阻止G2/M期的转变。基于与这些醌的分子模拟,推测了一个可能的Cdc25相互作用位点。我们建议基于这种化学结构的抑制剂可以作为探测Cdc25生物功能的有用工具。