Gao Yixuan, McPherson Lisa, Adimoolam Shanthi, Suresh Samyuktha, Wilson David L, Das Ishani, Park Elizabeth R, Ng Christine S C, Jun Yong Woong, Ford James M, Kool Eric T
Department of Chemistry and Stanford University, Stanford, CA 94305, United States.
Department of Medicine, Stanford University, Stanford, CA 94305, United States.
DNA Repair (Amst). 2025 Feb;146:103809. doi: 10.1016/j.dnarep.2025.103809. Epub 2025 Jan 14.
A potentially promising approach to targeted cancer prevention in genetically at-risk populations is the pharmacological upregulation of DNA repair pathways. SMUG1 is a base excision repair enzyme that ameliorates adverse genotoxic and mutagenic effects of hydrolytic and oxidative damage to pyrimidines. Here we describe the discovery and initial cellular activity of a small-molecule activator of SMUG1. Screening of a kinase inhibitor library and iterative rounds of structure-activity relationship studies produced compound 40 (SU0547), which activates SMUG1 by as much as 350 ± 60 % in vitro at 100 nM, with an AC of 4.3 ± 1.1 µM. To investigate the effect of compound 40 on endogenous SMUG1, we performed in vitro cell-based experiments with 5-hydroxymethyl-2'-deoxyuridine (5-hmdU), a pyrimidine oxidation product that is selectively removed by SMUG1. In several human cell lines, compound 40 at 3-5 µM significantly reduces the cytotoxicity of 5-hmdU and decreases levels of double-strand breaks induced by the damaged nucleoside. We conclude that the SMUG1 activator compound 40 is a useful tool to study the mechanisms of 5-hmdU toxicity and the potentially beneficial effects of suppressing damage to pyrimidines in cellular DNA.
在有遗传风险的人群中，一种具有潜在前景的靶向癌症预防方法是通过药理学手段上调DNA修复途径。SMUG1是一种碱基切除修复酶，可改善嘧啶水解和氧化损伤的不良基因毒性和诱变作用。在此，我们描述了一种SMUG1小分子激活剂的发现及其初步细胞活性。对激酶抑制剂文库进行筛选，并经过多轮构效关系研究，得到了化合物40（SU0547），该化合物在100 nM浓度下可在体外将SMUG1激活多达350±60%，激活常数为4.3±1.1 μM。为了研究化合物40对内源性SMUG1的影响，我们使用5-羟甲基-2'-脱氧尿苷（5-hmdU）进行了基于细胞的体外实验，5-hmdU是一种嘧啶氧化产物，可被SMUG1选择性去除。在几种人类细胞系中，3-5 μM的化合物40可显著降低5-hmdU的细胞毒性，并降低受损核苷诱导的双链断裂水平。我们得出结论，SMUG1激活剂化合物40是研究5-hmdU毒性机制以及抑制细胞DNA中嘧啶损伤潜在有益作用的有用工具。
