KDM5B (also known as PLU-1 and JARID1B) is 2-oxoglutarate and Fe²⁺ dependent oxygenase that acts as a histone H3K4 demethylase, which is a key participant in inhibiting the expression of tumor suppressors as a drug target. Here, we present the discovery of pyrazole derivatives compound 5 by structure-based virtual screening and biochemical screening with IC₅₀ of 9.320 μM against KDM5B, and its subsequent optimization to give 1-(4-methoxyphenyl)-N-(2-methyl-2-morpholinopropyl)-3-phenyl-1H-pyrazole-4-carboxamide (27 ab), a potent KDM5B inhibitor with IC₅₀ of 0.0244 μM. In MKN45 cells, compound 27 ab can bind and stabilize KDM5B and induce the accumulation of H3K4me2/3, bona fide substrates of KDM5B, while keep the amount of H3K4me1, H3K9me2/3 and H3K27me2 without change. Further biological study also indicated that compound 27 ab is a potent cellular active KDM5B inhibitor that can inhibit MKN45 cell proliferation, wound healing and migration. In sum, our finding gives a novel structure for the discovery of KDM5B inhibitor and targeting KDM5B may be a new therapeutic strategy for gastric cancer treatment.

KDM5B（也称为PLU-1和JARID1B）是2-氧戊二酸和Fe ²⁺依赖性加氧酶，可作为组蛋白H3K4脱甲基酶，是抑制肿瘤抑制因子（作为药物靶标）表达的关键参与者。在这里，我们介绍了通过基于结构的虚拟筛选和生化筛选发现吡唑衍生物化合物5的效果，针对KDM5B的IC ₅₀为9.320μM，随后对其进行了优化以得到1-（4-甲氧基苯基）-N-（2-甲基- 2-吗啉代丙基）-3-苯基-1H-吡唑-4-羧酰胺（27 ab），一种有效的KDM5B抑制剂，IC ₅₀为0.0244μM 。在MKN45细胞中，化合物27 ab可以结合和稳定KDM5B并诱导H3K4me2 / 3（真正的KDM5B底物）积累，同时保持H3K4me1，H3K9me2 / 3和H3K27me2的含量不变。进一步的生物学研究还表明，化合物27 ab是一种有效的细胞活性KDM5B抑制剂，可以抑制MKN45细胞增殖，伤口愈合和迁移。总而言之，我们的发现为发现KDM5B抑制剂提供了一种新颖的结构，靶向KDM5B可能是胃癌治疗的新治疗策略。