Synthesis and Biological Investigation of Phenothiazine-Based Benzhydroxamic Acids as Selective Histone Deacetylase 6 Inhibitors
JOURNAL OF MEDICINAL CHEMISTRY
Authors: Voegerl, Katharina; Ong, Nghia; Senger, Johanna; Herp, Daniel; Schmidtkunz, Karin; Marek, Martin; Mueller, Martin; Bartel, Karin; Shaik, Tajith B.; Porter, Nicholas J.; Robaa, Dina; Christianson, David W.; Romier, Christophe; Sippl, Wolfgang; Jung, Manfred; Bracher, Franz
Abstract
The phenothiazine system was identified as a favorable cap group for potent and selective histone deacetylase 6 (HDAC6) inhibitors. Here, we report the YJ It z 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 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.
Synthesis and biological evaluation of acridine-based histone deacetylase inhibitors as multitarget agents against Alzheimer's disease
EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
Authors: Tseng, Hui-Ju; Lin, Mei-Hsiang; Shiao, Young-Ji; Yang, Ying-Chen; Chu, Jung-Chun; Chen, Chun-Yung; Chen, Yi-Ying; Lin, Tony Eight; Su, Chih-Jou; Pan, Shiow-Lin; Chen, Liang-Chieh; Wang, Chen-Yu; Hsu, Kai-Cheng; Huang, Wei-Jan
Abstract
Multitarget agents simultaneously trigger molecules in functionally complementary pathways, and are therefore considered to have potential in effectively treating Alzheimer's disease (AD), which has a complex pathogenetic mechanism. In this study, the HDAC inhibitor core is incorporated into the acetylcholine esterase (ACE) inhibitor acridineederived moiety and resulted in compounds that exhibited higher class IIa HDAC (4, 5, 7, and 9)- and class IIb HDAC6-inhibiting activity when compared to the pan-HDAC inhibitor SAHA in clinical practice. One of these compounds, 11b, displayed greater selectivity toward HDAC6 than other isoform enzymes. In contrast, the activity of compound 6a was selective toward class IIa HDAC and HDAC6. These two compounds exhibited strong activity against A beta-aggregation as well as significantly disrupted Ab-oligomer. Additionally, 11b and 6a strongly inhibited AChE. These experimental findings demonstrate that compounds 11b and 6a are HDAC-A beta-aggregation-AChE inhibitors. Notably, they can enhance neurite outgrowth, but with no significant neurotoxicity. Further biological evaluation revealed the various cellular effects of multitarget compounds 11b and 6a, which have the potential to treat AD. (c) 2020 Elsevier Masson SAS. All rights reserved.