Ren Ji-Xia, Cheng Zhong, Huang Yu-Xin, Zhao Jing-Feng, Guo Peng, Zou Zhong-Mei, Xie Yong
Institute of Medicinal Plant Development, Chinese Academy of Medical Science & Peking Union Medical College, 151 Malianwa North Road, Haidian District, Beijing 100193, China,; College of Life Science, Liaocheng University, Liaocheng 252059, Shandong, China.
Department of Biochemistry and Molecular Biology, Ministry of Education Key Laboratory of Cellular Physiology, Shanxi University, Taiyuan 030001, Shanxi, China.
Biomed Pharmacother. 2017 May;89:376-385. doi: 10.1016/j.biopha.2017.02.064. Epub 2017 Feb 27.
Dual-specificity phosphatase 26 (DUSP26) has recently emerged as a target for treatment of human cancers. However, only two small-molecule inhibitors of DUSP26 are known so far, namely NSC-87877 and ethyl-3, 4-dephostatin. DUSP26 contains an N-terminal region (residues 1-60) and a conserved C-terminal catalytic domain (residues 61-211, DUSP26-C). The crystal structure of DUSP26-C, showing a catalytically inactive conformation of the active site, was reported in a previous study. However, the detailed catalytic mechanism of DUSP26 cannot be described based on that structure. In this study, the 3D structure of DUSP26 (residues 42-211) adopting catalytically active conformation, was built by homology modeling, and the established 3D structure was validated using enzyme kinetic assays. Pharmacophore modeling based on the validated 3D structure of human DUSP26 was carried out. The established pharmacophore model was considered as a 3D query for retrieving novel DUSP26 inhibitors from the chemical databases "Diversity Libraries" (129,087 compounds). Next, a docking study was performed to refine the obtained hit compounds. Then a total of 100 compounds were selected based on the ranking order and visual examination, which were then evaluated by an enzyme-based assay. Eight compounds were found to have inhibitory activities against DUSP26, and the most potent compound was assigned No. F1063-0967 with an IC value of 11.62μM. The inhibitory activity of F1063-0967 against DUSP26 is higher than that of NCS87877 (IC value: 16.67±2.89μM), but lower than that of ethyl-3, 4-dephostatin (IC value: 6.8±0.41μM). MTT assay results revealed that F1063-0967 can induce apoptosis in IMR-32 cell line with an IC value of 4.13μM. These results suggest that F1063-0967 should be investigated further for other pharmacological properties.
双特异性磷酸酶26（DUSP26）最近已成为治疗人类癌症的一个靶点。然而，迄今为止已知的DUSP26小分子抑制剂只有两种，即NSC-87877和3,4-去磷抑素乙酯。DUSP26包含一个N端区域（第1至60位氨基酸残基）和一个保守的C端催化结构域（第61至211位氨基酸残基，DUSP26-C）。先前的一项研究报道了DUSP26-C的晶体结构，其显示了活性位点的催化无活性构象。然而，基于该结构无法描述DUSP26的详细催化机制。在本研究中，通过同源建模构建了具有催化活性构象的DUSP26（第42至211位氨基酸残基）的三维结构，并使用酶动力学分析对所建立的三维结构进行了验证。基于已验证的人类DUSP26三维结构进行了药效团建模。所建立的药效团模型被视为一个三维查询，用于从化学数据库“多样性文库”（129,087种化合物）中检索新型DUSP26抑制剂。接下来，进行了对接研究以优化获得的命中化合物。然后根据排名顺序和视觉检查总共选择了100种化合物，随后通过基于酶的分析对其进行评估。发现有8种化合物对DUSP26具有抑制活性，最有效的化合物被命名为F1063-0967，其IC值为11.62μM。F1063-0967对DUSP26的抑制活性高于NCS87877（IC值：16.67±2.89μM），但低于3,4-去磷抑素乙酯（IC值：6.8±0.41μM）。MTT分析结果表明，F1063-0967能够诱导IMR-32细胞系凋亡，IC值为4.13μM。这些结果表明，F1063-0967的其他药理特性值得进一步研究。
