Probing the Roles of SUMOylation in Cancer Cell Biology Using a Selective SAE inhibitor. Homo sapiens

Small ubiquitin-like modifier (SUMO) family proteins regulate target protein functions by post-translational modification. However, a potent and selective inhibitor to target the SUMO pathway has been lacking. Here we describe ML-792, the first mechanism-based SUMO-activating enzyme (SAE) inhibitor with nanomolar potency in cellular assays. ML-792 selectively blocks SAE enzyme activity and total SUMOylation, which leads to reduced cancer cell proliferation. Moreover, induction of the MYC oncogene increased the ML-792 mediated viability effect in cancer cells, indicating potential application of SAE inhibitors in MYC-amplified tumors. Using ML-792, we further explored the critical roles of SUMOylation in mitotic progression and chromosome segregation. Furthermore, expression of an SAE catalytic subunit (UBA2) mutant S95N/M97T rescued SUMOylation loss and the mitotic defect induced by ML-792, confirming the selectivity of ML-792. As a potent and selective SAE inhibitor, ML-792 provides rapid loss of endogenously SUMOylated proteins allowing for novel insights into SUMO biology. Overall design: RNA-SEQ was used to analyze changes in mRNA profiles of human colon and breast cancer cells treated with ML00754792 SAEi

小泛素样修饰蛋白（small ubiquitin-like modifier, SUMO）家族通过翻译后修饰调控靶蛋白的功能。然而，长期以来始终缺乏可靶向SUMO通路的强效选择性抑制剂。本研究报道了ML-792——首个基于作用机制的SUMO激活酶（SUMO-activating enzyme, SAE）抑制剂，其在细胞实验中展现出纳摩尔级的抑制活性。ML-792可选择性阻断SAE的酶活性与整体SUMO化修饰过程，进而抑制癌细胞增殖。进一步研究发现，MYC癌基因的诱导表达会增强ML-792介导的癌细胞活力抑制效应，提示SAE抑制剂在MYC扩增型肿瘤中的潜在应用价值。借助ML-792，本研究深入探究了SUMO化修饰在有丝分裂进程与染色体分离中的关键调控作用。此外，过表达SAE催化亚基UBA2的S95N/M97T突变体，可挽救ML-792诱导的SUMO化修饰缺失与有丝分裂缺陷，从而证实了ML-792的选择性。作为一种强效选择性SAE抑制剂，ML-792可快速清除内源性SUMO化修饰蛋白，为SUMO生物学研究提供全新视角。整体实验设计：本研究采用RNA测序（RNA-SEQ）分析经ML00754792（SAE抑制剂）处理的人类结肠癌与乳腺癌细胞的mRNA表达谱变化。