Alfano Luigi, Iannuzzi Carmelina Antonella, Barone Daniela, Forte Iris Maria, Ragosta Maria Carmen, Cuomo Maria, Mazzarotti Giulio, Dell'Aquila Milena, Altieri Angela, Caporaso Antonella, Roma Cristin, Marra Laura, Boffo Silvia, Indovina Paola, De Laurentiis Michelino, Giordano Antonio
Cell Biology and Biotherapy Unit, Istituto Nazionale Tumori-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS)-Fondazione G. Pascale, Napoli, Italy.
Breast Unit, Istituto Nazionale Tumori-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS)-Fondazione G. Pascale, Napoli, Italy.
Oncogene. 2024 Apr;43(17):1263-1273. doi: 10.1038/s41388-024-02982-w. Epub 2024 Mar 4.
DNA double-strand breaks (DSBs) contribute to genome instability, a key feature of cancer. DSBs are mainly repaired by homologous recombination (HR) and non-homologous end-joining (NHEJ). We investigated the role of an isoform of the multifunctional cyclin-dependent kinase 9, CDK9-55, in DNA repair, by generating CDK9-55-knockout HeLa clones (through CRISPR-Cas9), which showed potential HR dysfunction. A phosphoproteomic screening in these clones treated with camptothecin revealed that CDC23 (cell division cycle 23), a component of the E3-ubiquitin ligase APC/C (anaphase-promoting complex/cyclosome), is a new substrate of CDK9-55, with S588 being its putative phosphorylation site. Mutated non-phosphorylatable CDC23(S588A) affected the repair pathway choice by impairing HR and favouring error-prone NHEJ. This CDK9 role should be considered when designing CDK-inhibitor-based cancer therapies.
DNA双链断裂（DSB）会导致基因组不稳定，这是癌症的一个关键特征。DSB主要通过同源重组（HR）和非同源末端连接（NHEJ）进行修复。我们通过生成CDK9-55基因敲除的HeLa克隆（通过CRISPR-Cas9技术）来研究多功能细胞周期蛋白依赖性激酶9的一种亚型CDK9-55在DNA修复中的作用，这些克隆显示出潜在的HR功能障碍。在用喜树碱处理的这些克隆中进行的磷酸化蛋白质组学筛选表明，E3泛素连接酶后期促进复合物/细胞周期体（APC/C）的一个组分细胞分裂周期蛋白23（CDC23）是CDK9-55的一个新底物，S588是其假定的磷酸化位点。突变的不可磷酸化的CDC23（S588A）通过损害HR并倾向于易出错的NHEJ来影响修复途径的选择。在设计基于CDK抑制剂的癌症治疗方案时，应考虑CDK9的这种作用。
