Poletto Mattia, Malfatti Matilde C, Dorjsuren Dorjbal, Scognamiglio Pasqualina L, Marasco Daniela, Vascotto Carlo, Jadhav Ajit, Maloney David J, Wilson David M, Simeonov Anton, Tell Gianluca
Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland.
Mol Carcinog. 2016 May;55(5):688-704. doi: 10.1002/mc.22313. Epub 2015 Apr 11.
The apurinic/apyrimidinic endonuclease 1 (APE1) is a protein central to the base excision DNA repair pathway and operates in the modulation of gene expression through redox-dependent and independent mechanisms. Aberrant expression and localization of APE1 in tumors are recurrent hallmarks of aggressiveness and resistance to therapy. We identified and characterized the molecular association between APE1 and nucleophosmin (NPM1), a multifunctional protein involved in the preservation of genome stability and rRNA maturation. This protein-protein interaction modulates subcellular localization and endonuclease activity of APE1. Moreover, we reported a correlation between APE1 and NPM1 expression levels in ovarian cancer, with NPM1 overexpression being a marker of poor prognosis. These observations suggest that tumors that display an augmented APE1/NPM1 association may exhibit increased aggressiveness and resistance. Therefore, targeting the APE1/NPM1 interaction might represent an innovative strategy for the development of anticancer drugs, as tumor cells relying on higher levels of APE1 and NPM1 for proliferation and survival may be more sensitive than untransformed cells. We set up a chemiluminescence-based high-throughput screening assay in order to find small molecules able to interfere with the APE1/NPM1 interaction. This screening led to the identification of a set of bioactive compounds that impair the APE1/NPM1 association in living cells. Interestingly, some of these molecules display anti-proliferative activity and sensitize cells to therapeutically relevant genotoxins. Given the prognostic significance of APE1 and NPM1, these compounds might prove effective in the treatment of tumors that show abundant levels of both proteins, such as ovarian or hepatic carcinomas.
脱嘌呤/脱嘧啶内切核酸酶1（APE1）是碱基切除DNA修复途径中的核心蛋白，通过氧化还原依赖性和非依赖性机制调节基因表达。APE1在肿瘤中的异常表达和定位是侵袭性和治疗抗性的常见标志。我们鉴定并表征了APE1与核磷蛋白（NPM1）之间的分子关联，NPM1是一种参与维持基因组稳定性和rRNA成熟的多功能蛋白。这种蛋白质-蛋白质相互作用调节APE1的亚细胞定位和内切核酸酶活性。此外，我们报道了卵巢癌中APE1和NPM1表达水平之间的相关性，NPM1过表达是预后不良的标志物。这些观察结果表明，显示出增强的APE1/NPM1关联的肿瘤可能表现出更高的侵袭性和抗性。因此，靶向APE1/NPM1相互作用可能代表一种开发抗癌药物的创新策略，因为依赖更高水平的APE1和NPM1进行增殖和存活的肿瘤细胞可能比未转化的细胞更敏感。我们建立了一种基于化学发光的高通量筛选测定法，以寻找能够干扰APE1/NPM1相互作用的小分子。该筛选导致鉴定出一组能够损害活细胞中APE1/NPM1关联的生物活性化合物。有趣的是，其中一些分子显示出抗增殖活性，并使细胞对治疗相关的基因毒素敏感。鉴于APE1和NPM1的预后意义，这些化合物可能在治疗同时显示这两种蛋白高水平的肿瘤（如卵巢癌或肝癌）中被证明是有效的。
