Senexins are potent and selective quinazoline inhibitors of CDK8/19 Mediator kinases. To improve their potency and metabolic stability, quinoline-based derivatives were designed through a structure-guided strategy based on the simulated drug–target docking model of Senexin A and Senexin B. A library of quinoline-Senexin derivatives was synthesized to explore the structure–activity relationship (SAR). An optimized compound 20a (Senexin C) exhibits potent CDK8/19 inhibitory activity with high selectivity. Senexin C is more metabolically stable and provides a more sustained inhibition of CDK8/19-dependent cellular gene expression when compared with the prototype inhibitor Senexin B. In vivo pharmacokinetic (PK) and pharmacodynamic (PD) evaluation using a novel tumor-based PD assay showed good oral bioavailability of Senexin C with a strong tumor-enrichment PK profile and tumor-PD marker responses. Senexin C inhibits MV4-11 leukemia growth in a systemic in vivo model with good tolerability.

中文翻译：

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具有肿瘤富集药代动力学的 CDK8/19 介质激酶的选择性和口服生物利用度喹啉-6-腈基抑制剂

Senexins 是 CDK8/19 介质激酶的强效选择性喹唑啉抑制剂。为了提高其效力和代谢稳定性，基于 Senexin A 和 Senexin B 的模拟药物-靶点对接模型，通过结构导向策略设计了基于喹啉的衍生物。合成了喹啉-Senexin 衍生物库以探索结构-活动关系（SAR）。优化的化合物20a(Senexin C) 具有高选择性的强效 CDK8/19 抑制活性。与原型抑制剂 Senexin B 相比，Senexin C 代谢更稳定，对 CDK8/19 依赖性细胞基因表达的抑制作用更持久。使用基于肿瘤的新型 PD 测定法进行体内药代动力学 (PK) 和药效学 (PD) 评估表明 Senexin C 具有良好的口服生物利用度，具有很强的肿瘤富集 PK 特征和肿瘤 PD 标志物反应。Senexin C 在全身性体内模型中抑制 MV4-11 白血病生长，具有良好的耐受性。