Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 1-5 Shimogamo-hangi-cho, Sakyo-ku, Kyoto 603-0823, Japan.
Nippon Pharmaceutical Chemicals Co., Ltd., 2-8-18 Higashiosaka-shi, Osaka 577-0056, Japan.
Bioorg Med Chem. 2019 Mar 15;27(6):1119-1129. doi: 10.1016/j.bmc.2019.02.006. Epub 2019 Feb 4.
Histone lysine demethylases (KDMs) have drawn much attention as targets of therapeutic agents. KDM5 proteins, which are Fe(II)/α-ketoglutarate-dependent demethylases, are associated with oncogenesis and drug resistance in cancer cells, and KDM5-selective inhibitors are expected to be anticancer drugs. However, few cell-active KDM5 inhibitors have been reported and there is an obvious need to discover more. In this study, we pursued the identification of highly potent and cell-active KDM5-selective inhibitors. Based on the reported KDM5 inhibitors, we designed several compounds by strategically merging two fragments for competitive inhibition with α-ketoglutarate and for KDM5-selective inhibition. Among them, compounds 10 and 13, which have a 3-cyano pyrazolo[1,5-a]pyrimidin-7-one scaffold, exhibited strong KDM5-inhibitory activity and significant KDM5 selectivity. In cellular assays using human lung cancer cell line A549, 10 and 13 increased the levels of trimethylated lysine 4 on histone H3, which is a specific substrate of KDM5s, and induced growth inhibition of A549 cells. These results should provide a basis for the development of cell-active KDM5 inhibitors to highlight the validity of our inhibitor-based fragment merging strategy.
组蛋白赖氨酸去甲基酶（KDMs）作为治疗靶点引起了广泛关注。KDM5 蛋白是一种依赖 Fe(II)/α-酮戊二酸的去甲基酶，与癌细胞的癌变和耐药性有关，因此 KDM5 选择性抑制剂有望成为抗癌药物。然而，目前报道的细胞活性 KDM5 抑制剂较少，因此需要进一步发现。在本研究中，我们致力于鉴定高效且细胞活性的 KDM5 选择性抑制剂。基于已报道的 KDM5 抑制剂，我们通过策略性地融合两种片段来设计了几种化合物，以竞争性抑制 α-酮戊二酸和 KDM5 选择性抑制。其中，具有 3-氰基吡唑并[1,5-a]嘧啶-7-酮骨架的化合物 10 和 13 表现出强烈的 KDM5 抑制活性和显著的 KDM5 选择性。在使用人肺癌细胞系 A549 的细胞实验中，化合物 10 和 13 增加了组蛋白 H3 上赖氨酸 4 的三甲基化水平，这是 KDM5 的特异性底物，并诱导了 A549 细胞的生长抑制。这些结果为开发细胞活性 KDM5 抑制剂提供了基础，突出了我们基于抑制剂的片段融合策略的有效性。
