USP5 Stabilizes IKBKG Through Deubiquitination to Suppress Ferroptosis and Promote Growth in Non-small Cell Lung Cancer

Abstract

Ferroptosis, a distinctive modality of cell mortality, has emerged as a critical regulator in non-small cell lung cancer (NSCLC). The deubiquitinating enzyme USP5 has established an oncogenic role in NSCLC. However, its biological relevance in NSCLC cell ferroptosis is currently unexplored. Expression analysis was performed by quantitative PCR (qPCR), immunohistochemistry (IHC) and immunoblotting. Animal xenograft studies were used to detect USP5's role in tumor growth. Cell proliferation, colony formation and apoptotic ratio were assessed by CCK-8, colony formation and flow cytometry assays, respectively. Cell ferroptosis was evaluated by gauging ROS, MDA, GSH, SOD, and Fe²⁺ contents. The USP5/IKBKG relationship and the ubiquitinated IKBKG were evaluated by Co-IP experiments. USP5 expression was elevated in human NSCLC. USP5 depletion suppressed NSCLC cell in vitro and in vivo growth and enhanced cell apoptosis. Moreover, USP5 depletion induced ferroptosis in NSCLC cell lines. Mechanistically, USP5 could enhance the stability of IKBKG protein through deubiquitination. Re-expression of IKBKG partially but significantly abolished USP5 depletion-mediated anti-growth and pro-ferroptosis effects in NSCLC cells. Our study demonstrates that USP5 suppresses ferroptosis and enhances growth in NSCLC cells by stabilizing IKBKG protein through deubiquitination. Targeting USP5 expression is an encouraging strategy to block NSCLC progression.

Keywords: Deubiquitination; Ferroptosis; NSCLC; Protein stability; USP5.