Department of Biomedical Sciences, University of Ulsan College of Medicine, ASAN Medical Center, Seoul, Korea.
Korean BioInformation Center (KOBIC), Daejeon, Korea.
J Natl Cancer Inst. 2017 Mar 1;109(3):1-11. doi: 10.1093/jnci/djw224.
The UBA6-specific E2 conjugating enzyme 1 (USE1) ubiquitin enzyme cascade is a poorly characterized arm of the ubiquitin-proteasome system. We investigated whether the UBA6-USE1 enzyme cascade plays a role in lung cancer tumorigenesis.
USE1 expression was assessed in tumor-normal paired samples from 106 lung cancer patients by immunoblot. USE1 was stably overexpressed and knocked down in lung cancer cell lines to evaluate cell proliferation, colony formation, and invasion. Xenograft models were used to determine the effects of USE1 on tumor growth (n = 7). Proteomics analysis was used to identify proteins interacting with USE1. The USE1 gene was sequenced in lung cancer patients, and missense mutations of USE1 were generated to evaluate its function. All statistical tests were two-sided.
USE1 proteins were frequently overexpressed in lung cancer patients (92.5%) Stable overexpression of USE1 increased cell proliferation ( P = .002), migration ( P < .001), and invasion ( P < .001), whereas knockdown of USE1 reduced cell proliferation ( P < .001), migration ( P = .003), and invasion in lung cancer cells and xenograft models ( P < .001). USE1 was found to have a conserved D-box domain, and the level of the protein was regulated by the anaphase-promoting complex. Several missense mutations in USE1 identified in patients prolong the stability of the protein.
USE1 proteins are frequently overexpressed in lung cancer, and missense mutations in USE1 prolong the half-life of the protein, promoting tumor formation. Our findings reveal novel roles for USE1 in lung cancer and the possible use of USE1 as a novel biomarker and therapeutic target for lung cancer treatment.
UBA6 特异性 E2 结合酶 1（USE1）泛素酶级联反应是泛素-蛋白酶体系统中一个特征不明显的分支。我们研究了 UBA6-USE1 酶级联反应是否在肺癌发生中起作用。
通过免疫印迹法评估 106 例肺癌患者肿瘤-正常配对样本中的 USE1 表达。在肺癌细胞系中稳定过表达和敲低 USE1，以评估细胞增殖、集落形成和侵袭。使用异种移植模型来确定 USE1 对肿瘤生长的影响（n=7）。使用蛋白质组学分析来鉴定与 USE1 相互作用的蛋白质。对肺癌患者的 USE1 基因进行测序，并生成 USE1 的错义突变以评估其功能。所有统计检验均为双侧。
USE1 蛋白在肺癌患者中频繁过表达（92.5%）。稳定过表达 USE1 增加了细胞增殖（P=0.002）、迁移（P<0.001）和侵袭（P<0.001），而敲低 USE1 则降低了肺癌细胞和异种移植模型中的细胞增殖（P<0.001）、迁移（P=0.003）和侵袭。发现 USE1 具有保守的 D 盒结构域，蛋白质水平受有丝分裂促进复合物调节。在患者中鉴定出的 USE1 几个错义突变延长了蛋白质的稳定性。
USE1 蛋白在肺癌中频繁过表达，而 USE1 的错义突变延长了蛋白质的半衰期，促进肿瘤形成。我们的研究结果揭示了 USE1 在肺癌中的新作用，以及将 USE1 用作肺癌治疗的新型生物标志物和治疗靶标的可能性。
