Development of non-ATP competitive chemical biology probes to elucidate mechanisms of PLK1 activation and stability.

Polo-like kinase1(PLK1)是调节细胞进入和进展的中心分子 有丝分裂。许多研究证实PLK1是一个抗肿瘤的药物靶点，它的抑制作用是 对癌细胞有很强的抗增殖作用。我们已经发现了一系列化合物，它们能结合 通过一个神秘的口袋有效地连接到名为abbapolins的PLK1的Polo-box结构域上，并且 以剂量依赖的方式诱导蛋白酶体介导的PLK1蛋白降解 无需添加配体来招募E3连接酶以促进泛素化(PROTAC 方法)。Abbapolins还能够抑制PLK1特异性标志物的磷酸化 同时有效抑制前列腺癌细胞系的增殖。由于这些令人兴奋的事情 观察到，我们建议进一步开发这些抑制剂作为有效的PBD抑制剂和 PLK1的降解者，同时将它们用作化学生物探针，以提供新的见解 PLK1活性的构象变化、底物识别和蛋白酶体调控 稳定性。因此，我们的实验将为PLK1在细胞内的调节提供新的线索 同时生成关于分子决定因素和特征的新数据 抑制力。反过来，这可能提供了对导致缺乏临床症状的因素的理解 奠定基础时PLK有丝分裂酶的ATP竞争性抑制剂的活性 对于临床前和临床开发，阿巴波林作为癌症治疗药物具有独特的 作用机制。

Polo-like kinase 1 (PLK1) is a central player in regulating entry into and progression through mitosis. Many studies have validated PLK1 as an anti-tumor drug target, and its inhibition is potently anti-proliferative to cancer cells. We have discovered a series of compounds that bind potently to the polo-box domain of PLK1 named abbapolins through a cryptic pocket and which induce proteasome mediated degradation of the PLK1 protein in a dose dependent manner without the addition of a ligand to recruit an E3 ligase to promote ubiquitination (PROTAC approach). The abbapolins are also able to inhibit the phosphorylation of a PLK1 specific marker while potently inhibiting the proliferation of prostate cancer cell lines. As a result of these exciting observations, we propose to further develop these inhibitors as potent PBD inhibitors and degraders of PLK1 while using them as chemical biology probes to provide new insights the regulation of PLK1 activity through conformational change, substrate recognition and proteasomal stability. Our experiments will therefore shed new light into the regulation of PLK1 at the cellular level while generating novel data on the molecular determinants and features important for inhibition. In turn this may provide understanding of the factors contributing to the lack of clinical activity for the ATP competitive inhibitors of the PLK mitotic kinases while laying the groundwork for preclinical and clinical development the abbapolins as cancer therapeutics with a unique mechanism of action.