Colony stimulating factor 1 receptor kinase (CSF1R) is a well validated molecular target for anticancer drug discovery. Herein, we report the design, synthesis, and structure–activity relationship study of 2-oxo-3,4-dihydropyrimido[4,5-d]pyrimidines as new orally bioavailable CSF1R inhibitors. One of the most promising compounds, 3bw, potently inhibits CSF1R kinase with an IC₅₀ value of 3.0 nM, while it is less potent against structurally related epidermal growth factor receptor (EGFR) and other kinases. The kinase inhibition of 3bw was further validated by Western blotting analysis in RAW264.7 macrophages. The molecule also potently blocks macrophage infiltration, abrogates the protumorigenic influences of macrophages, and exhibits reasonable pharmacokinetic profile. Compound 3bw may serve as a new valuable lead compound for future anticancer drug discovery.

中文翻译：

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作为新的集落刺激因子1受体（CSF1R）激酶抑制剂的2-Oxo-3,4-dihydropyrimido [4,5- d ]嘧啶的设计，合成及构效关系研究

集落刺激因子1受体激酶（CSF1R）是抗癌药物发现的一种经过充分验证的分子靶标。在这里，我们报告2-氧代-3,4-二氢嘧啶[4,5- d ]嘧啶类药物作为新型口服生物利用的CSF1R抑制剂的设计，合成和构效关系研究。最有前途的化合物之一3bw可以有效抑制CSF1R激酶，IC ₅₀值为3.0 nM，而对结构相关的表皮生长因子受体（EGFR）和其他激酶的抑制作用较小。3bw的激酶抑制通过RAW264.7巨噬细胞中的蛋白质印迹分析进一步证实了这一点。该分子还有效阻断巨噬细胞浸润，消除巨噬细胞的致瘤作用，并表现出合理的药代动力学特征。化合物3bw可以用作未来抗癌药物发现的新的有价值的先导化合物。