PDF(Pubmed)
Abstract：
Cyclosporin A (CsA) induces DNA double-strand breaks in LIG4 syndrome fibroblasts, specifically upon transit through S-phase. The basis underlying this has not been described. CsA-induced genomic instability may reflect a direct role of Cyclophilin A (CYPA) in DNA repair. CYPA is a peptidyl-prolyl cis-trans isomerase (PPI). CsA inhibits the PPI activity of CYPA. Using an integrated approach involving CRISPR/Cas9-engineering, siRNA, BioID, co-immunoprecipitation, pathway-specific DNA repair investigations as well as protein expression interaction analysis, we describe novel impacts of CYPA loss and inhibition on DNA repair. We characterise a direct CYPA interaction with the NBS1 component of the MRE11-RAD50-NBS1 complex, providing evidence that CYPA influences DNA repair at the level of DNA end resection. We define a set of genetic vulnerabilities associated with CYPA loss and inhibition, identifying DNA replication fork protection as an important determinant of viability. We explore examples of how CYPA inhibition may be exploited to selectively kill cancers sharing characteristic genomic instability profiles, including MYCN-driven Neuroblastoma, Multiple Myeloma and Chronic Myelogenous Leukaemia. These findings propose a repurposing strategy for Cyclophilin inhibitors.
摘要：
环孢菌素A(CsA)诱导LIG4综合征成纤维细胞DNA双链断裂,特别是在通过S阶段过渡时。尚未描述其基础。CsA诱导的基因组不稳定性可能反映亲环蛋白A（CYPA）在DNA修复中的直接作用。CYPA是肽基-氨酰顺反异构酶(PPI)。CsA抑制CYPA的PPI活性。使用涉及CRISPR/Cas9工程的综合方法，siRNABioID,免疫共沉淀,通路特异性DNA修复研究以及蛋白质表达相互作用分析，我们描述了CYPA丢失和抑制对DNA修复的新影响。我们表征了CYPA与MRE11-RAD50-NBS1复合物的NBS1成分的直接相互作用，提供CYPA在DNA末端切除水平上影响DNA修复的证据。我们定义了一组与CYPA丢失和抑制相关的遗传脆弱性，确定DNA复制叉保护是生存力的重要决定因素。我们探索了如何利用CYPA抑制来选择性杀死共享特征性基因组不稳定性谱的癌症的例子。包括MYCN驱动的神经母细胞瘤，多发性骨髓瘤和慢性粒细胞白血病。这些发现提出了亲环蛋白抑制剂的再利用策略。
