Werner syndrome RecQ helicase (WRN), a member of the RecQ helicase family, has recently been identified as a synthetic lethal target in microsatellite instability (MSI) tumors. The triazolo-pyrimidine compound HRO761 is the first WRN inhibitor to enter clinical trials, but research on this scaffold remains limited. Here, we designed a series of derivatives to systematically study the structure-activity relationship (SAR) of triazolo-pyrimidine scaffolds, leading to the discovery of compound S35. S35 exhibited excellent WRN helicase inhibitory activity (ADP-Glo kinase assay IC₅₀ = 16.1 nM, fluorometric helicase assay IC₅₀ = 23.5 nM). Additionally, S35 exhibited excellent cellular selectivity, with antiproliferative activity against multiple MSI cell lines (GI₅₀ = 36.4−306 nM), while the GI₅₀ values for multiple microsatellite stability (MSS) cell lines were greater than 20,000 nM. Furthermore, we observed that compound S35 induced DNA damage and caused G2/M cell cycle arrest in MSI cells, which did not occur in MSS cells. S35 demonstrated favorable oral pharmacokinetic properties, with oral administration resulting in dose-dependent tumor growth inhibition in the SW48 xenograft model. These findings provide a promising outlook for the development of WRN inhibitors for the treatment of MSI tumors.

中文翻译：

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三唑并嘧啶衍生物作为 WRN 抑制剂治疗 MSI 肿瘤的设计、合成和构效关系研究


Werner 综合征 RecQ 解旋酶 （WRN） 是 RecQ 解旋酶家族的一员，最近已被确定为微卫星不稳定性 （MSI） 肿瘤中的合成致死靶标。三唑并嘧啶化合物 HRO761 是第一个进入临床试验的 WRN 抑制剂，但对该支架的研究仍然有限。在这里，我们设计了一系列衍生物来系统研究三唑并嘧啶支架的构效关系 （SAR），从而发现了化合物 S35。S35 表现出优异的 WRN 解旋酶抑制活性 （ADP-Glo 激酶测定 IC₅₀ = 16.1 nM，荧光解旋酶测定 IC₅₀ = 23.5 nM）。此外，S35 表现出优异的细胞选择性，对多种 MSI 细胞系具有抗增殖活性 （GI₅₀ = 36.4-306 nM），而多种微卫星稳定性 （MSS） 细胞系的 GI₅₀ 值大于 20,000 nM。此外，我们观察到化合物 S35 诱导 DNA 损伤并导致 MSI 细胞中的 G2/M 细胞周期停滞，这在 MSS 细胞中未发生。S35 表现出良好的口服药代动力学特性，口服给药在 SW48 异种移植模型中导致剂量依赖性肿瘤生长抑制。这些发现为开发用于治疗 MSI 肿瘤的 WRN 抑制剂提供了有希望的前景。