Discovery of Selective Histone Deacetylase 1 and 2 Inhibitors: Screening of a Focused Library Constructed by Click Chemistry, Kinetic Binding Analysis, and Biological Evaluation

Histone deacetylase 1 and 2 (HDAC1/2) inhibitors are
potentially
useful as tools for probing the biological functions of the isoforms
and as therapeutic agents for cancer and neurodegenerative disorders.
To discover potent and selective inhibitors, we screened a focused
library synthesized by using click chemistry and obtained KPZ560 as an HDAC1/2-selective inhibitor. Kinetic binding analysis revealed
that KPZ560 inhibits HDAC2 through a two-step slow-binding
mechanism. In cellular assays, KPZ560 induced a dose-
and time-dependent increase of histone acetylation and showed potent
breast cancer cell growth-inhibitory activity. In addition, gene expression
analyses suggested that the two-step slow-binding inhibition by KPZ560 regulated the expression of genes associated with cell
proliferation and DNA damage. KPZ560 also induced neurite
outgrowth of Neuro-2a cells and an increase in the spine density of
granule neuron dendrites of mice. The unique two-step slow-binding
character of o-aminoanilides such as KPZ560 makes them interesting candidates as therapeutic agents.

组蛋白脱乙酰化酶1和2（HDAC1/2）的抑制剂在探究异构体生物学功能方面具有潜在的应用价值，且可作为治疗癌症和神经退行性疾病的治疗性药物。为发现高效且具有选择性的抑制剂，本研究通过点击化学合成了一组针对性的化合物库，并从中筛选出KPZ560作为HDAC1/2选择性抑制剂。动力学结合分析显示，KPZ560通过两步缓慢结合机制抑制HDAC2。在细胞实验中，KPZ560诱导了剂量和时间依赖性的组蛋白乙酰化增加，并展现出对乳腺癌细胞生长的强大抑制作用。此外，基因表达分析表明，KPZ560通过两步缓慢结合机制调控与细胞增殖和DNA损伤相关的基因表达。KPZ560还促进了神经-2a细胞的神经突生长，并增加了小鼠颗粒神经元树突棘密度。具有独特两步缓慢结合特性的o-氨基苯胺类化合物如KPZ560，使其成为治疗药物的有趣候选者。