Synthesis and pharmacological characterization of novel histone deacetylase 6 inhibitors

新型组蛋白脱乙酰酶6抑制剂的合成及药理学表征

• 批准号: 251120574
• 负责人: Professor Dr. Oliver Holger Krämer
• 金额: --
• 依托单位: Institut für Toxikologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/251120574?language=en
• 关键词: Synthesis; pharmacological; characterization; novel; histone

Histone deacetylases (HDACs) are epigenetic regulators catalyzing the deacetylation of lysine residues in proteins. HDACs are often overexpressed in cancer cells, in which they causally contribute to tumorigenesis. Histone deacetylase inhibitors (HDACi) inhibit protein deacetylation and alter gene expression and signaling. Consequently, cancer cell growth becomes compromised. HDACi are particularly effective against leukemia which is often not curable. Broad-range HDACi (pan-HDACi) inhibit several HDAC isoenzymes and produce general cytotoxicity. Isoenzyme-specific HDACi generate fewer side effects. Within the proposed project we plan to synthesize HDAC6 inhibitors with advanced chemistry (Prof. Mahboobi) and to test them in vitro and in cell based biological assays (PD. Dr. Krämer).HDAC6 has two catalytic domains and several specific functions and substrates. It is yet often unclear whether the catalytic activity of HDAC6 against certain substrates depends on both HDAC domains. The cytoskeletal protein tubulin-alpha and the chaperone HSP90 are targets of HDAC6. Deacetylated HSP90 assists the folding of oncoproteins including the leukemia fusion proteins BCR-ABL, AML1-ETO, and PML-RARalpha, mutant FLT3-ITD, the pan-leukemic marker protein WT1, and oncogenic p53. These and further cancer-relevant substrates of HDAC6 suggest the usefulness of HDAC6 inhibitors. The biological role of HDAC6 is though still incompletely understood and there are some controversies. These partly originate from the use of compounds that were erroneously assumed to be specific for HDAC6. In preliminary studies, we have synthesized novel and potent HDAC6 inhibitors. They exhibit potent cytotoxic and cytostatic activity in several cancer cell lines. We also show for the first time that the expression of survivin, a promoter of tumorigenesis and chemoresistance, depends on HDAC6. Moreover, our new inhibitors demonstrate combined cytotoxic activity with Imatinib against BCR-ABL transformed leukemic cells. At the molecular level this effect is linked to the depletion of BCR-ABL and WT1 and an accumulation of acetylated tubulin-alpha.Based on these data as well as on docking studies with crystal structures and homology models, we will synthesize and characterize even more potent and specific HDAC6 inhibitors. Furthermore, we aim to develop irreversible inhibitors for HDAC6. Such agents are a new pharmacological principle of HDAC6 inhibition. We expect that lower drug doses will sufficiently block HDAC6 due to a lesser detachment from HDAC6. The initial biological characterization of our new compounds targeting HDAC6 will mainly investigate their potential as pharmacological agents for the treatment of acute and myeloid leukemia. Data that we will collect with our novel inhibitors can also generally increase our understanding of the molecular effects and biological functions of HDAC6 in tumor cells.

组蛋白脱乙酰酶（HDAC）是催化蛋白质中赖氨酸残基脱乙酰化的表观遗传调节剂。HDAC通常在癌细胞中过表达，在癌细胞中它们因果地促成肿瘤发生。组蛋白去乙酰化酶抑制剂（HDACi）抑制蛋白质去乙酰化并改变基因表达和信号传导。因此，癌细胞的生长受到损害。HDACi对通常不可治愈的白血病特别有效。宽范围HDACi（pan-HDACi）抑制几种HDAC同工酶并产生一般细胞毒性。同工酶特异性HDACi产生更少的副作用。在拟议的项目中，我们计划用先进的化学（Mahboobi教授）合成HDAC 6抑制剂，并在体外和基于细胞的生物测定（PD）中对其进行测试。HDAC 6有两个催化结构域和几个特定的功能和底物。目前尚不清楚HDAC 6对某些底物的催化活性是否取决于两个HDAC结构域。细胞骨架蛋白微管蛋白-α和分子伴侣HSP 90是HDAC 6的靶标。去乙酰化的HSP 90有助于癌蛋白的折叠，包括白血病融合蛋白BCR-ABL、AML 1-ETO和PML-RAR alpha、突变体FLT 3-ITD、泛白血病标记蛋白WT 1和致癌p53。HDAC 6的这些和其他癌症相关底物表明HDAC 6抑制剂的有用性。HDAC 6的生物学作用仍然不完全清楚，存在一些争议。这些部分源于使用被错误地认为对HDAC 6具有特异性的化合物。在初步研究中，我们已经合成了新的和有效的HDAC 6抑制剂。它们在几种癌细胞系中表现出有效的细胞毒性和细胞抑制活性。我们还首次表明，生存素的表达，肿瘤发生和化疗耐药性的启动子，依赖于HDAC 6。此外，我们的新抑制剂显示出与伊马替尼联合对BCR-ABL转化白血病细胞的细胞毒活性。在分子水平上，这种效应与BCR-ABL和WT 1的消耗和乙酰化微管蛋白-alpha的积累有关。基于这些数据以及与晶体结构和同源模型的对接研究，我们将合成和表征更有效和特异的HDAC 6抑制剂。此外，我们的目标是开发HDAC 6的不可逆抑制剂。这些药物是HDAC 6抑制的新药理学原理。我们预期较低的药物剂量将充分阻断HDAC 6，因为与HDAC 6的脱离较少。我们靶向HDAC 6的新化合物的初步生物学特性将主要研究它们作为治疗急性和髓性白血病的药理学试剂的潜力。我们将用我们的新型抑制剂收集的数据也可以普遍增加我们对HDAC 6在肿瘤细胞中的分子效应和生物学功能的理解。