SKP2 promotes the metastasis of pancreatic ductal adenocarcinoma by suppressing TRIM21-mediated PSPC1 degradation

Despite significant advances in diagnostic techniques and treatment approaches, the prognosis of pancreatic ductal adenocarcinoma (PDAC) is still poor. Previous studies have reported that S-phase kinase-associated protein 2 (SKP2), a subunit of the SCF E3 ubiquitin ligase complex, is engaged in the malignant biological behavior of some tumor entities. However, SKP2 has not been fully investigated in PDAC. In the present study, it was observed that high expression of SKP2 significantly correlates with decreased survival time. Further experiments suggested that SKP2 promotes metastasis by interacting with the putative transcription factor paraspeckle component 1 (PSPC1). According to the results of coimmunoprecipitation and ubiquitination assays, SKP2 depletion resulted in the polyubiquitination of PSPC1, followed by its degradation. Furthermore, the SKP2mediated ubiquitination of PSPC1 partially depended on the activity of the E3 ligase TRIM21. In addition, inhibition of the SKP2/PSPC1 axis by SMIP004, a traditional inhibitor of SKP2, impaired the migration of PDAC cells. In summary, this study provides novel insight into the mechanisms involved in PDAC malignant progression. Targeting the SKP2/PSPC1 axis is a promising strategy for the treatment of PDAC.