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Updated: Oct 29, 2026

In vitro Organoid Culture of Primary Mouse Colon Tumors
Published on: May 17, 2013
USP18 promotes colorectal cancer cell proliferation and migration in association with KRT16 stabilization
Lin Zhang1, Xin Li1, Hongjie Yang1
1Affiliated Hospital of Jiaxing University, The First Hospital of Jiaxing, No. 1882, South Zhonghuan Road, Nanhu District, Jiaxing City, Zhejiang Province 314001, China.
Background:
The ubiquitin-specific peptidase 18 (USP18) has been implicated in colorectal cancer (CRC), but its downstream effector molecules remain incompletely defined.
Methods:
USP18-interacting proteins were identified by immunoprecipitation-mass spectrometry (IP-MS) and validated by co-immunoprecipitation (co-IP). The regulation of KRT16 by USP18 was examined by qPCR, Western blotting, ubiquitination assays and cycloheximide (CHX) chase experiments in SW480 cells. Functional assays were performed in SW480, HT-29 and LoVo cells, comprising CCK-8 proliferation and wound-healing assays in all three cell lines, Transwell migration assays in SW480 cells, and Transwell invasion assays in HT-29 and LoVo cells. Clinical relevance was evaluated in the TCGA and GSE39582 cohorts and in a 100-case hospital cohort by immunohistochemistry (IHC) and paired Western blotting.
Results:
IP-MS identified KRT16 as a USP18-associated protein. USP18 associated with endogenous KRT16, reduced KRT16 ubiquitination and prolonged the half-life of KRT16 protein. KRT16 and USP18 were concurrently upregulated in CRC in both the TCGA and GSE39582 cohorts; KRT16 expression correlated with USP18 expression (R = 0.68, P < 2.2 × 10-16), discriminated tumor from normal tissue (AUC = 0.899; 95% CI 0.852-0.945) and indicated poor overall survival (KRT16: HR = 2.024, 95% CI 1.273-3.218, P = 0.0029; externally validated in GSE39582, P = 0.0012). In the hospital cohort, high KRT16 expression (61.0%) was associated with T stage, and paired Western blots (n = 14) confirmed coordinated upregulation of USP18 and KRT16. Functionally, KRT16 knockdown reduced proliferation and impaired wound closure across all three cell lines, reduced Transwell migration in SW480 cells, and reduced invasion in HT-29 and LoVo cells, thereby attenuating the pro-tumor effects of USP18 overexpression.
Conclusion:
USP18 stabilizes KRT16 protein through deubiquitination and thereby promotes CRC cell proliferation and migration across multiple cellular backgrounds. These findings support the USP18-KRT16 axis as a candidate molecular axis warranting further preclinical evaluation in CRC.
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