Department of Pharmacy-Center for Drug Research , Ludwig-Maximilians University Munich , Butenandtstr. 5-13 , 81377 Munich , Germany.
Institute of Pharmaceutical Sciences , University of Freiburg , Albertstraße 25 , 79104 Freiburg , Germany.
J Med Chem. 2019 Feb 14;62(3):1138-1166. doi: 10.1021/acs.jmedchem.8b01090. Epub 2019 Feb 1.
The phenothiazine system was identified as a favorable cap group for potent and selective histone deacetylase 6 (HDAC6) inhibitors. Here, we report the preparation and systematic variation of phenothiazines and their analogues containing a benzhydroxamic acid moiety as the zinc-binding group. We evaluated their ability to selectively inhibit HDAC6 by a recombinant HDAC enzyme assay, by determining the protein acetylation levels in cells by western blotting (tubulin vs histone acetylation), and by assessing their effects on various cancer cell lines. Structure-activity relationship studies revealed that incorporation of a nitrogen atom into the phenothiazine framework results in increased potency and selectivity for HDAC6 (more than 500-fold selectivity relative to the inhibition of HDAC1, HDAC4, and HDAC8), as rationalized by molecular modeling and docking studies. The binding mode was confirmed by co-crystallization of the potent azaphenothiazine inhibitor with catalytic domain 2 from Danio rerio HDAC6.
苯并噻嗪系统被确定为具有高效和选择性的组蛋白去乙酰化酶 6（HDAC6）抑制剂的理想盖帽基团。在这里，我们报告了苯并噻嗪及其类似物的制备和系统变化，这些化合物含有苯甲羟肟酸部分作为锌结合基团。我们通过重组 HDAC 酶测定法评估了它们通过选择性抑制 HDAC6 的能力，通过 Western blot（微管蛋白与组蛋白乙酰化）测定细胞中蛋白质乙酰化水平，以及通过评估它们对各种癌细胞系的影响来评估。构效关系研究表明，将氮原子引入苯并噻嗪骨架中可显著提高对 HDAC6 的选择性和效力（与抑制 HDAC1、HDAC4 和 HDAC8 相比，选择性超过 500 倍），这可以通过分子建模和对接研究得到合理化。通过与斑马鱼 HDAC6 的催化结构域 2 共结晶，证实了该有效氮杂苯并噻嗪抑制剂的结合模式。
