尿路上皮性膀胱癌（UBC）是世界上最常见的恶性肿瘤之一，具有显著的肿瘤异质性。阐明能够用于治疗侵袭性UBC的分子机制是一项特别相关的目标。蛋白质泛素化是一种重要的翻译后修饰（PTM），通过蛋白酶体介导靶蛋白的降解。然而，异常蛋白质泛素化在UBC发展中的作用以及其推动肿瘤进展的潜在机制尚不清楚。在本研究中，我们利用CRISPR-CRISPR相关蛋白（Cas）9技术，鉴定了泛素E3连接酶ANAPC11，即负责有丝分裂期促进复合物/环酶（APC/C）的关键亚单位，作为UBC细胞中的一个潜在致癌分子。我们的临床分析显示，ANAPC11的高表达与高T分期、阳性淋巴结转移（LN）和UBC患者的不良预后显著相关。通过一系列体外实验，我们证明ANAPC11增加了UBC细胞的增殖和浸润能力，而ANAPC11的敲除则抑制了UBC细胞的生长和LN转移。通过免疫沉淀结合质谱分析，我们确认了ANAPC11增加了Forkhead转录因子FOXO3的泛素化水平。由此导致的FOXO3蛋白稳定性降低导致了细胞周期调节因子p21的下调以及雄激素受体信号转导的下游效应蛋白GULP1表达的降低。综上所述，这些发现表明ANAPC11通过调节FOXO3蛋白降解在UBC中扮演着致癌角色。ANAPC11-FOXO3调控轴可能成为UBC的新型治疗靶点。© 2023. 作者。

Urothelial bladder cancer (UBC) is one of the most prevalent malignancies worldwide, with striking tumor heterogeneity. Elucidating the molecular mechanisms that can be exploited for the treatment of aggressive UBC is a particularly relevant goal. Protein ubiquitination is a critical post-translational modification (PTM) that mediates the degradation of target protein via the proteasome. However, the roles of aberrant protein ubiquitination in UBC development and the underlying mechanisms by which it drives tumor progression remain unclear. In this study, taking advantage of clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein (Cas) 9 technology, we identified the ubiquitin E3 ligase ANAPC11, a critical subunit of the anaphase-promoting complex/cyclosome (APC/C), as a potential oncogenic molecule in UBC cells. Our clinical analysis showed that elevated expression of ANAPC11 was significantly correlated with high T stage, positive lymph node (LN) metastasis, and poor outcomes in UBC patients. By employing a series of in vitro experiments, we demonstrated that ANAPC11 enhanced the proliferation and invasiveness of UBC cells, while knockout of ANAPC11 inhibited the growth and LN metastasis of UBC cells in vivo. By conducting immunoprecipitation coupled with mass spectrometry, we confirmed that ANAPC11 increased the ubiquitination level of the Forkhead transcription factor FOXO3. The resulting decrease in FOXO3 protein stability led to the downregulation of the cell cycle regulator p21 and decreased expression of GULP1, a downstream effector of androgen receptor signaling. Taken together, these findings indicated that ANAPC11 plays an oncogenic role in UBC by modulating FOXO3 protein degradation. The ANAPC11-FOXO3 regulatory axis might serve as a novel therapeutic target for UBC.© 2023. The Author(s).