Structure-Activity Relationship Studies of Fostriecin, Cytostatin, and Key Analogs, with PP1, PP2A, PP5, and (β12-β13)-Chimeras (PP1/PP2A and PP5/PP2A), Provide Further Insight into the Inhibitory Actions of Fostriecin Family Inhibitors
Structure-Activity Relationship Studies of Fostriecin, Cytostatin, and Key Analogs, with PP1, PP2A, PP5, and (β12-β13)-Chimeras (PP1/PP2A and PP5/PP2A), Provide Further Insight into the Inhibitory Actions of Fostriecin Family Inhibitors
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DOI：
10.1124/jpet.109.155630
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发表时间：
2009-10-01
影响因子：
3.5
通讯作者：
Honkanen, Richard E.
中科院分区：
文献类型：
--
作者：
Swingle, Mark R.;Amable, Lauren;Honkanen, Richard E.
Fostriecin和cytostatin是结构相关的丝氨酸/苏氨酸磷酸酶的天然抑制剂，具有很好的抗肿瘤活性。这些抗肿瘤剂的全合成使得能够产生结构类似物，其可用于探索母体化合物中所含特征的生物学意义。在此，在并行磷酸酶测定中测试了fostriecin、cytostatin和10种关键结构类似物的抑制活性，以进一步表征其对PP1c的抑制活性（Ser/Thr蛋白磷酸酶1催化亚基），PP2Ac（丝氨酸/苏氨酸蛋白磷酸酶2A催化亚基），PP5c（Ser/Thr蛋白磷酸酶5催化亚基）和PP1的嵌合体（Ser/Thr蛋白磷酸酶1）和PP5（Ser/Thr蛋白磷酸酶5），其中使用定点诱变将预测与PP2A（Ser/Thr蛋白磷酸酶2A）接触的抑制剂的关键残基引入PP1和PP5中。数据证实了C9-磷酸和C11-醇对一般抑制的重要性，并进一步证明了预测的C3与PP2A β 12-β 13环中独特半胱氨酸（Cys（269））相互作用的重要性。数据还表明，不饱和内酯以外的其他特征有助于抑制效力和选择性。值得注意的是，缺乏整个内酯亚基的磷霉素衍生物表现出对PP2A的显著效力和选择性，同时对PP1和PP1/PP2A-PP5/PP2A-嵌合体具有显著降低的和相似的活性，所述嵌合体对磷霉素和细胞抑制素两者的敏感性都大大增加。这表明其他特征[e]。例如，在一个实施例中，（Z，Z，E）-三烯]也有助于抑制选择性。当考虑与以前的数据，这些研究表明，尽管PP1，PP2A和PP5的催化位点的高结构保守性，高选择性的催化抑制剂的发展应该是可行的。
Fostriecin and cytostatin are structurally related natural inhibitors of serine/threonine phosphatases, with promising antitumor activity. The total synthesis of these antitumor agents has enabled the production of structural analogs, which are useful to explore the biological significance of features contained in the parent compounds. Here, the inhibitory activity of fostriecin, cytostatin, and 10 key structural analogs were tested in side-by-side phosphatase assays to further characterize their inhibitory activity against PP1c (Ser/Thr protein phosphatase 1 catalytic subunit), PP2Ac (Ser/Thr protein phosphatase 2A catalytic subunit), PP5c (Ser/Thr protein phosphatase 5 catalytic subunit), and chimeras of PP1 (Ser/Thr protein phosphatase 1) and PP5 (Ser/Thr protein phosphatase 5), in which key residues predicted for inhibitor contact with PP2A (Ser/Thr protein phosphatase 2A) were introduced into PP1 and PP5 using site-directed mutagenesis. The data confirm the importance of the C9-phosphate and C11-alcohol for general inhibition and further demonstrate the importance of a predicted C3 interaction with a unique cysteine (Cys(269)) in the beta 12-beta 13 loop of PP2A. The data also indicate that additional features beyond the unsaturated lactone contribute to inhibitory potency and selectivity. Notably, a derivative of fostriecin lacking the entire lactone subunit demonstrated marked potency and selectivity for PP2A, while having substantially reduced and similar activity against PP1 and PP1/PP2A- PP5/PP2A-chimeras that have greatly increased sensitivity to both fostriecin and cytostatin. This suggests that other features [e. g., the (Z,Z,E)-triene] also contribute to inhibitory selectivity. When considered together with previous data, these studies suggest that, despite the high structural conservation of the catalytic site in PP1, PP2A and PP5, the development of highly selective catalytic inhibitors should be feasible.