结直肠癌是全球第三大常见恶性肿瘤，也是癌症相关死亡的主要原因之一。据报道，泛素特异性肽酶 18 (USP18) 蛋白在不同的肿瘤类型中发挥不同的肿瘤相关作用。在这里，我们初步研究了结肠腺癌（COAD）中USP18的表达和信号通路。通过实时定量PCR来评估培养细胞中USP18的mRNA水平。采用免疫组织化学染色探讨临床 COAD 样本中 USP18 的蛋白表达。使用 Lipo3000 将小干扰 RNA 瞬时转染至 SW480 和 HT29 细胞中，从而实现特异性敲低。进行cell conting kit-8测定、transwell测定和matrigel-transwell测定分别评估增殖、迁移和侵袭能力。进行蛋白质印迹分析下游信号通路。使用卡方检验以及单变量和多变量分析来评估临床数据。对小鼠模型的异种移植物进行评估以验证体外研究结果。在 COAD 组织中发现了较高的 USP18 水平，并且与晚期肿瘤阶段呈正相关。 USP18蛋白高表达表明COAD患者预后较差。沉默 USP18 通过破坏细胞外信号调节激酶 (ERK) 蛋白的稳定性并抑制 ERK 下游通路来抑制 COAD 细胞增殖和侵袭。同时用 USP18 沉默干扰素刺激基因 15 (ISG15) 可以部分挽救肿瘤细胞的活力，表明其参与了 USP18 信号传导。 USP18的致癌作用也在小鼠模型中得到证实。USP18通过ISG15-ERK通路在结肠腺癌中发挥致癌作用。 USP18 高表达表明结肠腺癌患者的临床结果不佳。© 2024 John Wiley

Colorectal cancer is the third most common malignancy worldwide and is one of the leading causes of cancer-related mortality. Ubiquitin-specific peptidase 18 (USP18) protein has been reported to exert different tumor-related effects in distinct tumor types. Here, we initially investigated the expression and signaling pathways of USP18 in colon adenocarcinoma (COAD).A quantitative real-time PCR was conducted to evaluate the mRNA level of USP18 in cultured cells. Immunohistochemical staining was used to explore the protein expression of USP18 in clinical COAD samples. Specific knockdown was achieved by transient transfection of small interfering RNAs into SW480 and HT29 cells using Lipo3000. Cell conting kit-8 assay, transwell assay and matrigel-transwell assays were conducted to evaluate proliferation, migration and invasion capacities, respectively. Western blotting was performed to analyze downstream signaling pathways. A chi-squared test and univariate and multivariate analyses were used to evaluate the clinical data. Xenografts from mice model were assessed to validate the in vitro findings.Higher USP18 level was identified in COAD tissues and was positively correlated with advanced tumor stage. High USP18 protein expression indicated poorer prognosis of COAD patients. Silencing USP18 suppressed COAD cell proliferation and invasion via destabilizing extracellular signal-regulated kinase (ERK) protein and suppressing ERK downstream pathways. Simultaneously silencing interferon-stimulated gene 15 (ISG15) with USP18 can partially rescue the tumor cell viability, indicating its involvement in USP18 signaling. The oncogenic effects of USP18 were also confirmed in mice models.USP18 plays oncogenic effects in colon adenocarcinoma via ISG15-ERK pathways. High USP18 expression indicates poor clinical outcomes for colon adenocarcinoma patients.© 2024 John Wiley & Sons Ltd.