ProteomicCharacterization of NEDD4 Unveils Its PotentialNovel Downstream Effectors in Gastric Cancer

The E3 ubiquitin ligase neural precursor cell-expressed developmentally down-regulated 4 (NEDD4) is involved in various cancer signaling pathways, including PTEN/AKT. However, its role in promoting gastric cancer (GC) progression is unclear. This study was conducted to elucidate the role of NEDD4 in GC progression. We found that the inhibition of NEDD4 expression significantly reduced the migratory and proliferative abilities of GC cells, with minimal impact on the PTEN expression or <i>p</i>-AKT activation, suggesting that NEDD4 may exert its GC-promoting effects through alternative pathways. To gain novel insights into the role of NEDD4 in GC, we performed a comprehensive proteomic analysis to search for proteins with altered expression levels following <i>NEDD</i>4 gene knockdown, identifying a total of 3916 proteins. Pathway analysis of differentially expressed proteins (DEPs) indicated the potential involvement of NEDD4 in cancer-related metabolic pathways. Furthermore, the protein–protein interaction network of the DEPs revealed enriched core modules, highlighting key cellular processes and signaling pathways regulated by NEDD4 in GC. Additionally, we identified proteins whose expression was altered by NEDD4 inhibition, some of which were associated with poor prognosis in GC. These findings suggest that these proteins may act as downstream effectors that contribute to NEDD4-mediated GC progression.