Shao L, Lewin N E, Lorenzo P S, Hu Z, Enyedy I J, Garfield S H, Stone J C, Marner F J, Blumberg P M, Wang S
Drug Discovery Program, University of Michigan Cancer Center, Department of Internal Medicine, University of Michigan, 1500 E. Medical Center Drive, Ann Arbor, Michigan 48109-0934, USA.
J Med Chem. 2001 Nov 8;44(23):3872-80. doi: 10.1021/jm010258f.
Since 1990, the National Cancer Institute has performed extensive in vitro screening of compounds for anticancer activity. To date, more than 70 000 compounds have been screened for their antiproliferation activities against a panel of 60 human cancer cell lines. We probed this database to identify novel structural classes with a pattern of biological activity on these cell lines similar to that of the phorbol esters. The iridals form such a structural class. Using the program Autodock, we show that the iridals dock to the same position on the C1b domain of protein kinase C delta as do the phorbol esters, with the primary hydroxyl group of the iridal at the C3 position forming two hydrogen bonds with the amide group of Thr12 and with the carbonyl group of Leu 21 and the aldehyde oxygen of the iridal forming a hydrogen bond with the amide group of Gly23. Biological analysis of two iridals, NSC 631939 and NSC 631941, revealed that they bound to protein kinase C alpha with K(i) values of 75.6 +/- 1.3 and 83.6 +/- 1.5 nM, respectively. Protein kinase C is now recognized to represent only one of five families of proteins with C1 domains capable of high-affinity binding of diacylglycerol and the phorbol esters. NSC 631939 and NSC 631941 bound to RasGRP3, a phorbol ester receptor that directly links diacylglycerol/phorbol ester signaling with Ras activation, with K(i) values of 15.5 +/- 2.3 and 41.7 +/- 6.5 nM, respectively. Relative to phorbol 12,13-dibutyrate, they showed 15- and 6-fold selectivity for RasGRP3. Both compounds caused translocation of green fluorescent protein tagged RasGRP3 expressed in HEK293 cells, and both compounds induced phosphorylation of ERK1/2, a downstream indicator of Ras activation, in a RasGRP3-dependent fashion. We conclude that the iridals represent a promising structural motif for design of ligands for phorbol ester receptor family members.
自1990年以来,美国国家癌症研究所对化合物进行了广泛的体外抗癌活性筛选。迄今为止,已经针对60种人类癌细胞系组成的细胞群,对7万多种化合物的抗增殖活性进行了筛选。我们探究了这个数据库,以识别在这些细胞系上具有与佛波酯类似生物活性模式的新型结构类别。鸢尾酮类化合物即构成这样一种结构类别。使用Autodock程序,我们发现鸢尾酮类化合物与蛋白激酶Cδ的C1b结构域上的结合位置与佛波酯相同,鸢尾酮类化合物C3位的伯羟基与Thr12的酰胺基团以及Leu 21的羰基形成两个氢键,鸢尾酮类化合物的醛基氧与Gly23的酰胺基团形成一个氢键。对两种鸢尾酮类化合物NSC 631939和NSC 631941的生物学分析表明,它们与蛋白激酶Cα结合,解离常数(K(i))值分别为75.6±1.3和83.6±1.5 nM。蛋白激酶C现在被认为只是具有能够高亲和力结合二酰基甘油和佛波酯的C1结构域的五个蛋白家族之一。NSC 631939和NSC 631941与RasGRP3结合,RasGRP3是一种佛波酯受体,可将二酰基甘油/佛波酯信号传导与Ras激活直接联系起来,其解离常数(K(i))值分别为15.5±2.3和41.7±6.5 nM。相对于佛波醇12,13 - 二丁酸酯,它们对RasGRP3表现出15倍和6倍的选择性。这两种化合物都导致在HEK293细胞中表达的绿色荧光蛋白标记的RasGRP3发生易位,并且这两种化合物都以RasGRP3依赖的方式诱导Ras激活的下游指标ERK1/2的磷酸化。我们得出结论,鸢尾酮类化合物代表了一种有前景的结构基序,可用于设计佛波酯受体家族成员的配体。