Chiu Chien-Chih, Hsu Sheng-Kai, Liu Wangta, Lin I-Ling, Qiu Wenhua, Hsieh Ching-Hung, Chou Chon-Kit
Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan.
Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan.
Cancer Med. 2025 Aug;14(15):e71055. doi: 10.1002/cam4.71055.
Non-small cell lung cancer (NSCLC) is an aggressive and lethal malignancy with the highest cancer-related mortality rate. More than 50% of patients are diagnosed at advanced stages, often accompanied by chemoresistance and poor prognosis. Deubiquitinases (DUBs), which regulate various signaling pathways by removing ubiquitin moieties, are frequently dysregulated in tumors, including the ubiquitin-specific processing protease 15 (USP15). However, the biological role of USP15 in NSCLC progression remains poorly defined. This study aimed to investigate the biological function and mechanistic relevance of USP15 in NSCLC.
USP15 expression in human NSCLC tumor tissues and matched adjacent normal tissues was assessed by immunohistochemical staining. Western blotting was performed to evaluate USP15 protein levels in various NSCLC cell lines. Functional assays were conducted to examine the effects of USP15 knockdown on NSCLC cell growth, invasion, and epithelial-mesenchymal transition (EMT). Chemosensitivity assays were carried out using topotecan and irinotecan. Additionally, proteomic analysis was performed through immunoprecipitation of tGFP-tagged USP15 followed by LC-MS/MS to identify USP15-interacting proteins.
USP15 was significantly overexpressed in NSCLC tumor tissues compared to adjacent normal tissues, as confirmed by immunohistochemistry. This finding was further supported by western blot analysis showing elevated USP15 levels across multiple NSCLC cell lines. Knockdown of USP15 impaired NSCLC cell growth and invasion, reduced EMT marker expression, and re-sensitized cells to topotecan and irinotecan. Proteomic profiling identified USP15-interacting proteins enriched in the U2-type spliceosomal complex and RNA helicase activity, suggesting a role for USP15 in regulating pre-mRNA splicing.
This study demonstrates the oncogenic role of USP15 in NSCLC, highlighting its contribution to tumor progression, chemoresistance, and RNA processing. The findings provide mechanistic insights into how USP15 may drive NSCLC pathogenesis through modulation of spliceosome-associated proteins. These results support the potential of USP15 as both a diagnostic biomarker and a therapeutic target in NSCLC.
非小细胞肺癌（NSCLC）是一种侵袭性和致死性的恶性肿瘤，其癌症相关死亡率最高。超过50%的患者在晚期被诊断出来，常伴有化疗耐药性和预后不良。去泛素化酶（DUBs）通过去除泛素部分来调节各种信号通路，在肿瘤中经常失调，包括泛素特异性加工蛋白酶15（USP15）。然而，USP15在NSCLC进展中的生物学作用仍不清楚。本研究旨在探讨USP15在NSCLC中的生物学功能及其机制相关性。
通过免疫组织化学染色评估人NSCLC肿瘤组织和匹配的相邻正常组织中USP15的表达。进行蛋白质印迹法以评估各种NSCLC细胞系中USP15的蛋白水平。进行功能测定以检查USP15敲低对NSCLC细胞生长、侵袭和上皮-间质转化（EMT）的影响。使用拓扑替康和伊立替康进行化疗敏感性测定。此外，通过对带有tGFP标签的USP15进行免疫沉淀，随后进行液相色谱-串联质谱（LC-MS/MS）进行蛋白质组学分析，以鉴定与USP15相互作用的蛋白质。
免疫组织化学证实，与相邻正常组织相比，USP15在NSCLC肿瘤组织中显著过表达。蛋白质印迹分析进一步支持了这一发现，显示多个NSCLC细胞系中USP15水平升高。USP15敲低损害了NSCLC细胞的生长和侵袭，降低了EMT标志物的表达，并使细胞对拓扑替康和伊立替康重新敏感。蛋白质组学分析确定与USP15相互作用的蛋白质富含U2型剪接体复合物和RNA解旋酶活性，表明USP15在调节前体mRNA剪接中起作用。
本研究证明了USP15在NSCLC中的致癌作用，突出了其对肿瘤进展、化疗耐药性和RNA加工的贡献。这些发现为USP15如何通过调节剪接体相关蛋白驱动NSCLC发病机制提供了机制性见解。这些结果支持USP15作为NSCLC诊断生物标志物和治疗靶点的潜力。
