As one of the most promising anticancer target in protein arginine methyltransferase (PRMT) family, PRMT5 has been drawing more and more attentions, and many efforts have been devoted to develop its inhibitors. In this study, three PRMT5 inhibitors (9, 16, and 23) with novel scaffolds were identified by performing pharmacophore- and docking-based virtual screening combined with in vitro radiometric-based scintillation proximity assay (SPA). Substructure search based on the scaffold of the most active 9 afforded 26 additional analogues, and SPA results indicated that two analogues (9–1 and 9–2) showed increased PRMT5 inhibitory activity compared with the parental compound. Resynthesis of 9, 9–1, and 9–2 confirmed their PRMT5 enzymatic inhibition activity. In addition, compound 9–1 displayed selectivity against PRMT5 over other key homological members (PRMT1 and CARM1 (PRMT4)). While the structure–activity relationship (SAR) of this series of compounds was discussed to provide clues for further structure optimization, the probable binding modes of active compounds were also probed by molecular docking and molecular dynamics simulations. Finally, the antiproliferative effect of 9–1 on MV4-11 leukemia cell line was confirmed and its impact on regulating the target gene of PRMT5 was also validated. The hit compounds identified in this work have provided more novel scaffolds for future hit-to-lead optimization of small-molecule PRMT5 inhibitors.

作为蛋白质精氨酸甲基转移酶（PRMT）家族中最有希望的抗癌靶标之一，PRMT5受到越来越多的关注，并已致力于开发其抑制剂。在这项研究中，三PRMT5抑制剂（9，16，和23）与新的支架，通过执行pharmacophore-和基于对接虚拟筛选联合确定体外辐射基于闪烁亲近测定法（SPA）。根据最活跃的9的支架进行的亚结构搜索提供了26个其他类似物，而SPA结果表明，两个类似物（9 – 1和9 – 2）与亲本化合物相比显示出增加的PRMT5抑制活性。的再合成9，9 - 1，和9 - 2证实了他们的PRMT5酶抑制活性。此外，化合物9 - 1显示在其他关键同源构件抵抗PRMT5选择性（PRMT1和CARM1（PRMT4））。虽然讨论了该系列化合物的构效关系（SAR）为进一步优化结构提供了线索，但还通过分子对接和分子动力学模拟探索了活性化合物的可能结合方式。最后，抗增殖作用为9 – 1证实了其对MV4-11白血病细胞系的抑制作用，并且还证实了其对调节PRMT5的靶基因的影响。这项工作中确定的命中化合物为未来小分子PRMT5抑制剂的命中领先优化提供了更多新颖的支架。