Inhibitors of b-arrestin

最近在GPCR信号转导中的发现阐明了β-抑制蛋白的多种关键作用，β-抑制蛋白是调节GPCR内化和信号转导的支架蛋白。β-arrestins有望成为临床靶点，因为单个β-arrestin基因敲除的小鼠没有明显的表型，而β-arrestin 1和β-arrestin 2的双重敲除是致命的。此外，膀胱癌细胞表达升高水平的β-arrestin 2及其激活剂之一，血栓烷-β GPCR。这种增加与不良临床预后相关，并表明β-arrestin 2是膀胱癌的靶点。虽然GPCR是主要的临床靶点，但迄今为止还没有β-抑制蛋白的小分子调节剂。利用NICS Kraken超级计算机上的高性能对接，我们对140万个化合物库进行了虚拟筛选，并确定了约250种潜在的β-arrestin 2抑制剂。然后，我们创建并验证了靶向GPCR/B-arrestin 2相互作用的高通量和高内容筛选，并测试了61种预测的抑制性化合物，其中15种使受体内化降低> 40%，验证了我们的发现策略。我们将完成所有预测抑制剂的筛选，并进行先导优化，以提高其对β-arrestin 2的效力和选择性。所得到的β抑制蛋白2的第一选择性抑制剂将用于确定它们对模型细胞系统中下游GPCR信号传导事件的作用和选择性。我们还将使用膀胱癌的细胞模型和动物模型测试我们的β-arrestin 2抑制剂的抗癌活性。这项研究的成功将保证β-抑制蛋白2抑制剂作为膀胱癌和其他与异常β-抑制蛋白介导的信号转导相关的疾病的治疗剂的发展。

Recent discoveries in GPCR signaling have elucidated multiple critical roles of beta-arrestins which are scaffolding proteins that regulate GPCR internalization and signaling. Beta-arrestins are promising to clinical targets, because mice with a knockout of a single beta-arrestin have no overt phenotype, while dual knockout of beta-arrestin1 and beta-arrestin2 is lethal. Also, bladder cancer cells express elevated levels of beta-arrestin2 and one of its activators, the thromboxane-beta GPCR. This increase correlates with a poor clinical prognosis and suggests beta-arrestin2 as a bladder cancer target. Although GPCRs are a major clinical target, to date there are no small molecule regulators for beta-arrestins. Using high performance docking on the NICS Kraken supercomputer, we have conducted virtual screening of a 1.4 million compound library and identified ~250 potential beta-arrestin2 inhibitors. We then created and validated a high throughput and high-content screen targeting GPCR/ B-arrestin2 interactions and tested 61 predicted inhibitory compounds, 15 of which decreased receptor internalization by >40%, validating our discovery strategy. We will complete the screening of all the predicted inhibitors and carry out lead optimization to increase their potency and selectivity for beta-arrestin2. The resulting first selective inhibitors of betaarrestin2 will be used to determine their effect and selectivity on downstream GPCR signaling events in model cell systems. We will also test our beta-arrestin2 inhibitor for anticancer activity using cell based and animal models of bladder cancer. The success of this study will warrant the development of beta-arrestin2 inhibitors as therapeutic agents for bladder cancer and other diseases associated with aberrant betaarrestin- mediated signal transduction.