JOSD2 promotes breast cancer metastasis by deubiquitinating and stabilizing SMAD4

Breast cancer is one of the most common malignant tumors among women worldwide, and its high degree of metastasis significantly impacts treatment effectiveness leading to poor prognosis. The potential molecular mechanisms underlying breast cancer metastasis remain to be further elucidated. In this study, via database analysis, we revealed that the deubiquitinase josephin domain containing 2 (JOSD2) was abnormally amplified in patients with metastatic breast cancer, and was significantly negatively correlated with patient prognosis. By integrating data from the Gene Expression Omnibus (GEO) database and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway enrichment analysis, we found that the transforming growth factor beta (TGF-β) signaling pathway was significantly activated in breast cancer patients with increased JOSD2 expression. Further studies revealed that JOSD2 interacted with and stabilized SMAD family member 4 (SMAD4) by removing polyubiquitin chains. Inhibition of JOSD2 by RNA interference effectively inhibited the metastasis of breast cancer cells both in vitro and in vivo. In conclusion, our study not only reveals the role of JOSD2 in promoting breast cancer metastasis for the first time, but also indicates promising directions for the future development of deubiquitinase inhibitors, which could yield significant therapeutic benefits. Nevertheless, extensive research and development are required to fully realize this potential.