Fishel Melissa L, Wu Xue, Devlin Cecilia M, Logsdon Derek P, Jiang Yanlin, Luo Meihua, He Ying, Yu Zhangsheng, Tong Yan, Lipking Kelsey P, Maitra Anirban, Rajeshkumar N V, Scandura Glenda, Kelley Mark R, Ivan Mircea
From the Departments of Pediatrics, Wells Center for Pediatric Research, Pharmacology and Toxicology,
Microbiology and Immunology.
J Biol Chem. 2015 Jan 30;290(5):3057-68. doi: 10.1074/jbc.M114.621995. Epub 2014 Dec 9.
Apurinic/apyrimidinic endonuclease/redox factor-1 (APE1/Ref-1) (henceforth referred to as Ref-1) is a multifunctional protein that in addition to its base excision DNA repair activity exerts redox control of multiple transcription factors, including nuclear factor κ-light chain enhancer of activated B cells (NF-κB), STAT3, activator protein-1 (AP-1), hypoxia-inducible factor-1 (HIF-1), and tumor protein 53 (p53). In recent years, Ref-1 has emerged as a promising therapeutic target in cancer, particularly in pancreatic ductal carcinoma. Although a significant amount of research has centered on Ref-1, no wide-ranging approach had been performed on the effects of Ref-1 inhibition and transcription factor activity perturbation. Starting with a broader approach, we identified a previously unsuspected effect on the nuclear factor erythroid-related factor 2 (NRF2), a critical regulator of cellular defenses against oxidative stress. Based on genetic and small molecule inhibitor-based methodologies, we demonstrated that repression of Ref-1 potently activates NRF2 and its downstream targets in a dose-dependent fashion, and that the redox, rather than the DNA repair function of Ref-1 is critical for this effect. Intriguingly, our results also indicate that this pathway does not involve reactive oxygen species. The link between Ref-1 and NRF2 appears to be present in all cells tested in vitro, noncancerous and cancerous, including patient-derived tumor samples. In particular, we focused on understanding the implications of the novel interaction between these two pathways in primary pancreatic ductal adenocarcinoma tumor cells and provide the first evidence that this mechanism has implications for overcoming the resistance against experimental drugs targeting Ref-1 activity, with clear translational implications.
脱嘌呤/脱嘧啶内切核酸酶/氧化还原因子1（APE1/Ref-1）（以下简称Ref-1）是一种多功能蛋白质，除了具有碱基切除DNA修复活性外，还对多种转录因子发挥氧化还原调控作用，包括活化B细胞的核因子κ轻链增强子（NF-κB）、信号转导和转录激活因子3（STAT3）、活化蛋白1（AP-1）、缺氧诱导因子1（HIF-1）和肿瘤蛋白53（p53）。近年来，Ref-1已成为癌症尤其是胰腺导管癌中有前景的治疗靶点。尽管大量研究都集中在Ref-1上，但尚未对Ref-1抑制和转录因子活性扰动的影响进行广泛研究。从更广泛的方法入手，我们发现了对核因子红系相关因子2（NRF2）的一种先前未被怀疑的影响，NRF2是细胞抗氧化应激防御的关键调节因子。基于遗传学和小分子抑制剂方法，我们证明Ref-1的抑制以剂量依赖方式强力激活NRF2及其下游靶点，并且Ref-1的氧化还原而非DNA修复功能对这种效应至关重要。有趣的是，我们的结果还表明该途径不涉及活性氧。Ref-1和NRF2之间的联系似乎存在于体外测试的所有细胞中，包括非癌和癌细胞，以及患者来源的肿瘤样本。特别是，我们专注于了解这两条途径之间新型相互作用在原发性胰腺导管腺癌肿瘤细胞中的意义，并提供了首个证据表明该机制对克服针对Ref-1活性的实验药物耐药性具有意义，具有明确的转化意义。
