Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, U.K.
Leicester Institute of Structural and Chemical Biology, School of Chemistry, University of Leicester, Leicester LE1 7RH, U.K.
Biochemistry. 2023 Feb 7;62(3):645-656. doi: 10.1021/acs.biochem.2c00288. Epub 2022 Aug 10.
The class I histone deacetylase (HDAC) enzymes;HDAC1,2 and 3 form the catalytic engine of at least seven structurally distinct multiprotein complexes in cells. These molecular machines play a vital role in the regulation of chromatin accessibility and gene activity via the removal of acetyl moieties from lysine residues within histone tails. Their inhibition via small molecule inhibitors has beneficial effects in a number of disease types, including the clinical treatment of hematological cancers. We have previously reported a library of proteolysis targeting chimeras (PROTACs) incorporating a benzamide-based HDAC ligand (from CI-994), with an alkyl linker and ligand for the von Hippel-Lindau (VHL) E3 ubiquitin ligase that degrade HDAC1-3 at submicromolar concentrations. Here we report the addition of two novel PROTACs (JPS026 and JPS027), which utilize a ligand for the cellular inhibitor of apoptosis (IAP) family of E3 ligases. We found that both VHL (JPS004)- and IAP (JPS026)-based PROTACs degrade HDAC1-3 and induce histone acetylation to a similar degree. However, JPS026 is significantly more potent at inducing cell death in HCT116 cells than is JPS004. RNA sequencing analysis of PROTAC-treated HCT116 cells showed a distinct gene expression signature in which cell cycle and DNA replication machinery are repressed. Components of the mTORC1 and -2 complexes were also reduced, leading to an increase in FOXO3 and downstream target genes that regulate autophagy and apoptosis. In summary, a novel combination of HDAC and IAP ligands generates a PROTAC with a potent ability to stimulate apoptosis and differential gene expression in human cancer cells.
I 类组蛋白去乙酰化酶 (HDAC) 酶；HDAC1、2 和 3 形成至少七种结构不同的多蛋白复合物的催化引擎在细胞中。这些分子机器通过从组蛋白尾部赖氨酸残基上去除乙酰基来发挥重要作用，调节染色质的可及性和基因活性。通过小分子抑制剂抑制它们在多种疾病类型中具有有益的效果，包括血液系统癌症的临床治疗。我们之前报道了一个包含基于苯甲酰胺的 HDAC 配体（来自 CI-994）的蛋白酶体靶向嵌合体（PROTAC）文库，具有烷基连接子和用于 von Hippel-Lindau（VHL）E3 泛素连接酶的配体，可在亚微摩尔浓度下降解 HDAC1-3。在这里，我们报告了两种新型 PROTAC（JPS026 和 JPS027）的添加，它们利用细胞凋亡抑制剂（IAP）家族的 E3 连接酶的配体。我们发现，基于 VHL（JPS004）和 IAP（JPS026）的 PROTAC 都能降解 HDAC1-3，并诱导组蛋白乙酰化到相似的程度。然而，JPS026 在诱导 HCT116 细胞死亡方面比 JPS004 更有效。PROTAC 处理的 HCT116 细胞的 RNA 测序分析显示出一个独特的基因表达特征，其中细胞周期和 DNA 复制机制受到抑制。mTORC1 和 -2 复合物的成分也减少，导致 FOXO3 及其下游调节自噬和细胞凋亡的靶基因增加。总之，HDAC 和 IAP 配体的新型组合产生了一种具有强大能力的 PROTAC，可在人类癌细胞中刺激细胞凋亡和差异基因表达。
