Loss of TRAIP Could Attenuate the Breast Cancer Cells Development by Regulating PLSCR4 Stabilization

Tumor necrosis factor receptor-associated factor interacting protein (TRAIP) has emerged as a critical regulator of multiple oncogenic processes across various malignancies. However, its specific functional role and underlying mechanisms in breast cancer pathogenesis remain to be fully elucidated. Integrated bioinformatics analysis of TCGA and GTEx datasets was performed to assess TRAIP expression patterns. Complementary experimental validation was conducted using immunohistochemistry, qRT-PCR, and western blot in clinical specimens. Functional characterization of TRAIP in breast cancer cells was achieved through CCK-8 proliferation assays, colony formation analysis, transwell migration/invasion tests, wound healing experiments, and flow cytometric apoptosis detection. Mechanistic investigations employed co-immunoprecipitation and ubiquitination assays to delineate the TRAIP-PLSCR4 interaction, supplemented by rescue experiments to confirm functional interdependence. Consistent overexpression of TRAIP was observed in breast cancer tissues compared to normal controls. Genetic knockdown of TRAIP significantly attenuated malignant phenotypes, including: (1) reduction in cellular proliferation, (2) decrease in colony-forming capacity, (3) reduction in migratory/invasive potential, and (4) increase in apoptosis rates (Annexin V staining). Mechanistically, TRAIP functioned as an E3 ubiquitin ligase mediating proteasomal degradation of PLSCR4 through K48-linked polyubiquitination (co-IP validation). Notably, PLSCR4 silencing effectively rescued the tumor-suppressive effects of TRAIP knockdown. This study identifies a novel TRAIP/PLSCR4 regulatory axis in breast cancer pathogenesis, wherein TRAIP exerts its oncogenic function via ubiquitination-dependent degradation of tumor-suppressive PLSCR4. These findings position TRAIP as a promising therapeutic target for precision breast cancer interventions.