Synergistic inhibition of TNBC by USP33 and TAP63 through autophagy and ferroptosis activation.

Background: Triple-negative breast cancer (TNBC) is an aggressive malignancy lacking effective targeted therapies. Given the growing importance of regulated cell death pathways, we investigated the role of USP33 and its interaction with the tumor suppressor TAP63 in modulating ferroptosis and autophagy in TNBC.

Methods: An integrative approach combining bioinformatic screening, in vitro molecular and cellular assays, and in vivo xenograft models was employed to evaluate the USP33-TAP63 axis. Protein interaction and ubiquitination were assessed via co-immunoprecipitation and ubiquitin chain analysis. Ferroptosis and autophagy were monitored using fluorescence probes, electron microscopy, and key biomarkers. Statistical significance was assessed via Student's t-test and ANOVA.

Results: USP33 was significantly downregulated in TNBC tissues and cell lines, correlating with enhanced proliferation, migration, and epithelial-mesenchymal transition. Mechanistically, USP33 stabilized TAP63 through K48-linked deubiquitination, triggering autophagy and ferroptosis by disrupting mitochondrial function and redox balance. Co-overexpression of USP33 and TAP63 synergistically suppressed tumor growth in vitro and in vivo.

Conclusion: The USP33-TAP63 axis acts as a central regulator of autophagy and ferroptosis in TNBC, suppressing tumor progression via oxidative stress-induced cell death. These findings offer mechanistic insight and highlight this axis as a promising target for therapeutic intervention in TNBC.