Key Laboratory of Arrhythmias of the Ministry of Education of China, Research Center for Translational Medicine, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200092, China.
Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, 200092, China.
Breast Cancer Res Treat. 2022 Nov;196(1):31-44. doi: 10.1007/s10549-022-06711-3. Epub 2022 Aug 30.
Sirtuin7 (SIRT7), as a member of the sirtuin and NAD-dependent protein-modifying enzyme family, plays an important role in regulating cellular metabolism, stress responses, tumorigenesis, and aging. Ubiquitination and deubiquitination are reversible post-translational modifications that regulate protein stability, enzyme activity, protein-protein interactions, and cellular signaling transduction. However, whether SIRT7 is regulated by deubiquitination signaling is unclear. This study aims to elucidate the molecular mechanism of SIRT7 via deubiquitination signaling.
USP17L2 or SIRT7-targeting shRNAs were used to deplete USP17L2 or SIRT7. Western blot was applied to assess the effects of USP17L2 or SIRT7 depletion. A co-immunoprecipitation assay was used to detect the interaction relationship. Cell Counting Kit-8 assays were applied to assess the viability of breast cancer cells. An immunohistochemistry assay was employed to detect the protein level in samples from breast cancer patients, and the TCGA database was applied to analyze the survival rate of breast cancer patients. Statistical analyses were performed with the Student's t test (two-tailed unpaired) and χ test.
We find that the deubiquitinase USP17L2 interacts with and deubiquitinates SIRT7, thereby increasing SIRT7 protein stability. In addition, USP17L2 regulates DNA damage repair through SIRT7. Furthermore, SIRT7 polyubiquitination is increased by knocking down of USP17L2, which leads to cancer cells sensitizing to chemotherapy. In breast cancer patient samples, high expression of USP17L2 is correlated with increased levels of SIRT7 protein. In conclusion, our study demonstrates that the USP17L2-SIRT7 axis is the new regulator in DNA damage response and chemo-response, suggesting that USP17L2 may be a prognostic factor and a potential therapeutic target in breast cancer.
Our results highlighted that USP17L2 regulates the chemoresistance of breast cancer cells in a SIRT7-dependent manner. Moreover, the role of USP17L2 as a potential therapeutic target in breast cancer and a prognostic factor for patients was elucidated.
Sirtuin7（SIRT7）作为 sirtuin 和 NAD 依赖性蛋白修饰酶家族的一员，在调节细胞代谢、应激反应、肿瘤发生和衰老中发挥重要作用。泛素化和去泛素化是调节蛋白质稳定性、酶活性、蛋白质-蛋白质相互作用和细胞信号转导的可逆翻译后修饰。然而，SIRT7 是否受去泛素化信号调节尚不清楚。本研究旨在通过去泛素化信号阐明 SIRT7 的分子机制。
使用 USP17L2 或 SIRT7 靶向 shRNA 耗尽 USP17L2 或 SIRT7。Western blot 用于评估 USP17L2 或 SIRT7 耗竭的影响。免疫共沉淀实验用于检测相互作用关系。细胞计数试剂盒-8 用于评估乳腺癌细胞活力。免疫组织化学检测乳腺癌患者样本中的蛋白水平，TCGA 数据库用于分析乳腺癌患者的生存率。采用 Student's t 检验（双侧非配对）和 χ 检验进行统计分析。
我们发现去泛素酶 USP17L2 与 SIRT7 相互作用并使其去泛素化，从而增加 SIRT7 蛋白稳定性。此外，USP17L2 通过 SIRT7 调节 DNA 损伤修复。此外，敲低 USP17L2 会增加 SIRT7 的多泛素化，导致癌细胞对化疗敏感。在乳腺癌患者样本中，USP17L2 高表达与 SIRT7 蛋白水平升高相关。总之，本研究表明 USP17L2-SIRT7 轴是 DNA 损伤反应和化疗反应的新调节剂，提示 USP17L2 可能是乳腺癌的预后因素和潜在治疗靶点。
我们的结果强调了 USP17L2 以 SIRT7 依赖的方式调节乳腺癌细胞的化疗耐药性。此外，阐明了 USP17L2 作为乳腺癌潜在治疗靶点和预后因素的作用。
