Antibiotics Laboratory, RIKEN, Hirosawa, Wako-shi, Saitama, Japan; School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia.
Cancer Sci. 2013 Nov;104(11):1461-7. doi: 10.1111/cas.12246. Epub 2013 Sep 6.
Dysregulation of p27(Kip1) due to proteolysis that involves the ubiquitin ligase (SCF) complex with S-phase kinase-associated protein 2 (Skp2) as the substrate-recognition component (SCF(Skp2)) frequently results in tumorigenesis. In this report, we developed a high-throughput screening system to identify small-molecule inhibitors of p27(Kip1) degradation. This system was established by tagging Skp2 with fluorescent monomeric Azami Green (mAG) and CDK subunit 1 (Cks1) (mAGSkp2-Cks1) to bind to p27(Kip1) phosphopeptides. We identified two compounds that inhibited the interaction between mAGSkp2-Cks1 and p27(Kip1): linichlorin A and gentian violet. Further studies have shown that the compounds inhibit the ubiquitination of p27(Kip1) in vitro as well as p27(Kip1) degradation in HeLa cells. Notably, both compounds exhibited preferential antiproliferative activity against HeLa and tsFT210 cells compared with NIH3T3 cells and delayed the G1 phase progression in tsFT210 cells. Our approach indicates a potential strategy for restoring p27(Kip1) levels in human cancers.
由于涉及泛素连接酶 (SCF) 复合物与 S 期激酶相关蛋白 2 (Skp2) 作为底物识别组件 (SCF(Skp2)) 的蛋白酶解导致 p27(Kip1) 的失调,这常常导致肿瘤发生。在本报告中,我们开发了一种高通量筛选系统来鉴定 p27(Kip1) 降解的小分子抑制剂。该系统通过将 Skp2 标记为荧光单体 Azami Green (mAG) 和细胞周期蛋白依赖性激酶亚基 1 (Cks1) (mAGSkp2-Cks1) 来与 p27(Kip1) 磷酸肽结合,从而建立起来。我们鉴定出两种抑制 mAGSkp2-Cks1 与 p27(Kip1) 之间相互作用的化合物:林可霉素 A 和龙胆紫。进一步的研究表明,这些化合物在体外抑制 p27(Kip1) 的泛素化以及 HeLa 细胞中 p27(Kip1) 的降解。值得注意的是,与 NIH3T3 细胞相比,这两种化合物对 HeLa 和 tsFT210 细胞均表现出优先的抗增殖活性,并且延迟了 tsFT210 细胞的 G1 期进展。我们的方法为恢复人类癌症中的 p27(Kip1) 水平提供了一种潜在的策略。