Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.
State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China.
Clin Transl Med. 2022 Mar;12(3):e770. doi: 10.1002/ctm2.770.
Cyclin C (CCNC) was reported to take part in regulating mitochondria-derived oxidative stress under cisplatin stimulation. However, its effect in gastric cancer is unknown. This study aimed to investigate the role of cyclin C and its ubiquitylation in regulating cisplatin resistance in gastric cancer.
The interaction between HECT domain and ankyrin repeat-containing E3 ubiquitin-protein ligase 1 (HACE1) and cyclin C was investigated by GST pull-down assay, co-immunoprecipitation and ubiquitylation assay. Mitochondria-derived oxidative stress was studied by MitoSOX Red assay, seahorse assay and mitochondrial membrane potential measurement. Cyclin C-associated cisplatin resistance was studied in vivo via xenograft.
HACE1 catalysed the ubiquitylation of cyclin C by adding Lys11-linked ubiquitin chains when cyclin C translocates to cytoplasm induced by cisplatin treatment. The ubiquitin-modified cyclin C then anchor at mitochondira, which induced mitochondrial fission and ROS synthesis. Depleting CCNC or mutation on the ubiquitylation sites decreased mitochondrial ROS production and reduced cell apoptosis under cisplatin treatment. Xenograft study showed that disrupting cyclin C ubiquitylation by HACE1 conferred impairing cell apoptosis response upon cisplatin administration.
Cyclin C is a newly identified substrate of HACE1 E3 ligase. HACE1-mediated ubiquitylation of cyclin C sheds light on a better understanding of cisplatin-associated resistance in gastric cancer patients. Ubiquitylation of cyclin C by HACE1 regulates cisplatin-associated sensitivity in gastric cancer. With cisplatin-induced nuclear-mitochondrial translocation of cyclin C, its ubiquitylation by HACE1 increased mitochondrial fission and mitochondrial-derived oxidative stress, leading to cell apoptosis.
环蛋白 C（CCNC）被报道在顺铂刺激下参与调节线粒体来源的氧化应激。然而，其在胃癌中的作用尚不清楚。本研究旨在探讨环蛋白 C 及其泛素化在调节胃癌顺铂耐药中的作用。
通过 GST 下拉实验、共免疫沉淀和泛素化实验研究 HECT 结构域和含锚蛋白重复的 E3 泛素蛋白连接酶 1（HACE1）与环蛋白 C 之间的相互作用。通过 MitoSOX Red 测定法、 Seahorse 测定法和线粒体膜电位测定法研究线粒体来源的氧化应激。通过异种移植研究体内环蛋白 C 相关顺铂耐药情况。
当顺铂处理诱导环蛋白 C 向细胞质易位时，HACE1 通过添加 Lys11 连接的泛素链催化环蛋白 C 的泛素化。然后，泛素修饰的环蛋白 C 锚定在线粒体上，诱导线粒体裂变和 ROS 合成。在顺铂处理下，耗尽 CCNC 或泛素化位点突变会减少线粒体 ROS 的产生并降低细胞凋亡。异种移植研究表明，HACE1 破坏环蛋白 C 的泛素化会导致顺铂给药时细胞凋亡反应受损。
环蛋白 C 是 HACE1 E3 连接酶的新鉴定底物。HACE1 介导的环蛋白 C 泛素化有助于更好地理解胃癌患者顺铂相关耐药性。HACE1 对环蛋白 C 的泛素化调节胃癌中顺铂相关敏感性。随着顺铂诱导的环蛋白 C 核-线粒体易位，其被 HACE1 泛素化增加了线粒体裂变和线粒体来源的氧化应激，导致细胞凋亡。
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