IMR Press / FBL / Volume 27 / Issue 10 / DOI: 10.31083/j.fbl2710286
Open Access Original Research
The Deubiquitinating Enzyme USP4 Functions as an Oncoprotein in Gastric Cancer and Mediates NF-κB Signaling by Regulating PRL-3 Expression
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1 Department of Nursing Management, The First Affiliated Hospital of Soochow University, 215006 Suzhou, Jiangsu, China
2 Department of Gastroenterology, The First Affiliated Hospital of Soochow University, 215006 Suzhou, Jiangsu, China
*Correspondence: youwendao2016@126.com (Wendao You)
Academic Editor: Azhar Ali
Front. Biosci. (Landmark Ed) 2022, 27(10), 286; https://doi.org/10.31083/j.fbl2710286
Submitted: 25 July 2022 | Revised: 7 September 2022 | Accepted: 13 September 2022 | Published: 19 October 2022
(This article belongs to the Special Issue Ubiquitin Signaling in Health and Disease)
Copyright: © 2022 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.
Abstract

Background: It has been reported that ubiquitin specific peptidase 4 (USP4) was functional in several tumors, but its function and mechanism in gastric cancer were still unknown. Methods: Bioinformatic tools were used to predict the prognosis of gastric cancer patients and the expression levels of USP4 in gastric cancer. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunoblotting were carried out to detect the messenger RNA (mRNA) and protein levels. Cell viability of gastric cancer was evaluated by Cell Counting Kit-8 (CCK-8) assay. Cell line-derived xenograft models were established to evaluate the tumor growth of gastric cancer. Luciferase assay and immunoblotting were used to determine the activation of nuclear factor kappa B (NF-κB) signaling. Results: The public database Kaplan-Meier Plotter showed that gastric cancer patients with high USP4 expression had a shorter overall survival or post-progression survival than the patients with decreased USP4. Further studies indicated that USP4 was elevated in gastric cancer tumor tissues. In contrast, knockdown of USP4 markedly inhibited gastric cancer cell growth, and suppressed the tumor growth of gastric cancer. Further studies revealed that USP4 knockdown significantly suppressed NF-κB-driven luciferase activity, and inhibited the phosphorylation of NF-κB p65 in gastric cancer cells. Additionally, qRT-PCR analysis showed that USP4 knockdown significantly downregulated the expressions of cyclin D2 (CCND2) and B cell leukemia/lymphoma 2 (BCL2). We also found that USP4 knockdown decreased the expressions of phosphatase of regenerating liver-3 (PRL-3), in contrast, overexpression of PRL-3 attenuated the inhibitory effects of USP4 knockdown on NF-κB signaling and cell viability in gastric cancer cells. Finally, PR-619, which has been proven to inhibit the activities of USP4 and other deubiquitinases, could inhibit cell viability and NF-κB signaling in gastric cancer cells. Conclusions: This study indicated that elevated USP4 predicted a poor index for gastric cancer patients, and mediated gastric cancer cell growth by regulating PRL-3/NF-κB signaling, which suggested USP4 may be a novel therapeutic target for gastric cancer.

Keywords
USP4
gastric cancer
PRL-3
NF-κB
PR-619
Funding
81902399/National Natural Science Foundation of China
Figures
Fig. 1.
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