ABSTRACT
Recent studies have demonstrated that ubiquitin-specific protease 10 (USP10) plays a catalytic role in tumour suppression mainly by deubiquitinating its target proteins to enhance their stabilities. However, we found that USP10 could interact with and regulate the expression of oncogenic factor Musashi-2 (MSI2). We investigated whether USP10 positively regulates the expression of MSI2 by deubiquitination and confirmed the type of polyubiquitin chain that is linked to MSI2. We also explored the role of USP10 in regulating the proliferation of colon cancer through different experiments. This study provides a completely new perspective in understanding the role of USP10 in deubiquitination. In the future, USP10 may serve as a target for colon cancer treatment.
Subject(s)
Colonic Neoplasms/metabolism , RNA-Binding Proteins/chemistry , RNA-Binding Proteins/metabolism , Ubiquitin Thiolesterase/metabolism , Caco-2 Cells , Cell Line, Tumor , Cell Proliferation , Colonic Neoplasms/genetics , Gene Expression Regulation, Neoplastic , HCT116 Cells , HEK293 Cells , HT29 Cells , Humans , Lysine , Protein Stability , RNA-Binding Proteins/genetics , Ubiquitin Thiolesterase/genetics , Ubiquitination , Up-RegulationABSTRACT
PURPOSE: Recent studies have determined that cartilage oligomeric matrix protein (COMP) plays a vital role in carcinogenesis. We sought to clarify the role of COMP in colon cancer. METHODS: We investigated gene expression data from The Cancer Genome Atlas (TCGA) dataset. Tissue microarrays (TMA) containing paired samples from 253 patients with colon cancer were subjected to immunostaining. COMP levels in serum of colon cancer patients and healthy donors were measured with ELISA. We established COMP-knockout cells using the CRISPR/Cas9 system and COMP-overexpressing cells using lentiviral vectors to detect the effects of COMP on colon cancer cells using Cell Counting Kit-8 (CCK8), colony formation, apoptosis detection kit, and tumorigenesis assays in nude mice. RESULTS: The analysis of TCGA dataset and the results of the TMA suggested that COMP expression levels were significantly higher in cancer tissues than in adjacent normal tissues. Moreover, high COMP expression was correlated with the poor outcome of colon cancer patients. COMP levels in the sera of preoperative patients with colon cancer were much higher than those in healthy donors and were significantly reduced after colectomy. Colon cancer cells without COMP were defective with respect to the ability to proliferate, colony formation, the ability to resist 5-Fluorouracil-induced apoptosis and the growth of xenograft tumors in mice. Contrasting results were observed in COMP overexpressed cells. COMP promoted colon cancer cell proliferation partially through the activation of PI3K/ Akt/ mTOR/ p70S6K pathway. CONCLUSIONS: COMP may be a novel prognostic indicator and biomarker and also a potential therapeutic target for colon cancer.
