Ambrose Andrew J, Zerio Christopher J, Sivinski Jared, Schmidlin Cody J, Shi Taoda, Ross Alison B, Widrick Kimberly J, Johnson Steven M, Zhang Donna D, Chapman Eli
Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, 1703 East Mabel Street, PO Box 210207, Tucson, AZ 85721, USA.
Indiana University, School of Medicine, Department of Biochemistry and Molecular Biology, 635 Barnhill Dr., Indianapolis, IN 46202, USA.
Bioorg Med Chem Lett. 2019 Jul 15;29(14):1689-1693. doi: 10.1016/j.bmcl.2019.05.041. Epub 2019 May 20.
Glucose-regulated protein 78 (GRP78) is the ER resident 70 kDa heat shock protein 70 (HSP70) and has been hypothesized to be a therapeutic target for various forms of cancer due to its role in mitigating proteotoxic stress in the ER, its elevated expression in some cancers, and the correlation between high levels for GRP78 and a poor prognosis. Herein we report the development and use of a high throughput fluorescence polarization-based peptide binding assay as an initial step toward the discovery and development of GRP78 inhibitors. This assay was used in a pilot screen to discover the anti-infective agent, hexachlorophene, as an inhibitor of GRP78. Through biochemical characterization we show that hexachlorophene is a competitive inhibitor of the GRP78-peptide interaction. Biological investigations showed that this molecule induces the unfolded protein response, induces autophagy, and leads to apoptosis in a colon carcinoma cell model, which is known to be sensitive to GRP78 inhibition.
葡萄糖调节蛋白78（GRP78）是内质网驻留的70 kDa热休克蛋白70（HSP70），由于其在减轻内质网蛋白毒性应激中的作用、在某些癌症中的高表达以及GRP78高水平与不良预后之间的相关性，已被假设为各种癌症的治疗靶点。在此，我们报告了一种基于高通量荧光偏振的肽结合测定方法的开发和应用，作为发现和开发GRP78抑制剂的第一步。该测定方法用于初步筛选，以发现抗感染剂六氯酚作为GRP78的抑制剂。通过生化特性分析，我们表明六氯酚是GRP78-肽相互作用的竞争性抑制剂。生物学研究表明，该分子在已知对GRP78抑制敏感的结肠癌细胞模型中诱导未折叠蛋白反应、诱导自噬并导致细胞凋亡。
