Payton Marc, Chung Grace, Yakowec Peter, Wong Andrew, Powers Dave, Xiong Ling, Zhang Nancy, Leal Juan, Bush Tammy L, Santora Vincent, Askew Ben, Tasker Andrew, Radinsky Robert, Kendall Richard, Coats Steve
Department of Cancer Biology, Amgen, Inc., Thousand Oaks, California 91320-1789, USA.
Cancer Res. 2006 Apr 15;66(8):4299-308. doi: 10.1158/0008-5472.CAN-05-2507.
In eukaryotic cells, cyclin-dependent kinase (CDK) complexes regulate the temporal progression of cells through the cell cycle. Deregulation in the cell cycle is an essential component in the evolution of cancer. Here, we validate CDK1 and CDK2 as potential therapeutic targets using novel selective small-molecule inhibitors of cyclin B1/CDK1 and cyclin E2/CDK2 enzyme complexes (CDKi). Flow cytometry-based methods were developed to assess intracellular retinoblastoma (Rb) phosphorylation to show inhibition of the CDK pathway. Tumor cells treated with CDK inhibitors showed an overall decrease in cell proliferation, accumulation of cells in G1 and G2, and apoptosis in a cell line-specific manner. Although CDK inhibitors activate p53, the inhibitors were equipotent in arresting the cell cycle in isogenic breast and colon tumor cells lacking p53, suggesting the response is independent of p53. In vivo, the CDK inhibitors prevented the growth of colon and prostate tumors, blocked proliferation of tumor cells, and inhibited Rb phosphorylation. The discovery and evaluation of novel potent and selective CDK1 and CDK2 inhibitors will help delineate the role that CDK complexes play in regulating tumorigenesis.
在真核细胞中，细胞周期蛋白依赖性激酶（CDK）复合物通过细胞周期调节细胞的时间进程。细胞周期失调是癌症发生发展的一个重要因素。在此，我们使用细胞周期蛋白B1/CDK1和细胞周期蛋白E2/CDK2酶复合物（CDKi）的新型选择性小分子抑制剂，验证CDK1和CDK2作为潜在治疗靶点。我们开发了基于流式细胞术的方法来评估细胞内视网膜母细胞瘤（Rb）磷酸化，以显示CDK途径的抑制作用。用CDK抑制剂处理的肿瘤细胞表现出细胞增殖总体下降、G1期和G2期细胞积累以及细胞系特异性凋亡。尽管CDK抑制剂激活p53，但这些抑制剂在使缺乏p53的同基因乳腺和结肠肿瘤细胞的细胞周期停滞方面具有同等效力，表明该反应独立于p53。在体内，CDK抑制剂可阻止结肠和前列腺肿瘤的生长，阻断肿瘤细胞增殖，并抑制Rb磷酸化。新型强效和选择性CDK1和CDK2抑制剂的发现和评估将有助于阐明CDK复合物在调节肿瘤发生中所起的作用。
