DDX39A: A Key Proliferation-Promoting Protein in Gastric Cancer Identified through Proteomic Analysis

Purpose: Gastric cancer (GC) is a significant global health concern, with a particularly high prevalence in the southern Hebei province of China. This study aims to uncover key proteins associated with the occurrence of GC and thus provide new potential for the treatment of GC. Methods: In this study, we performed high-throughput proteomic analysis on GC and adjacent non-tumor tissues to identify abnormally expressed proteins, and then made GO enrichment, KEGG pathway and cluster analysis. Differentially expressed proteins were further screened and validated by parallel reaction monitoring (PRM) test, including DDX39A et al. Using immunohistochemistry (IHC), we examined DDX39A's expression and its clinical relevance in GC. We then knocked down DDX39A in AGS and MKN-74 cell lines using shRNA technology, and investigated the effects of DDX39A knockdown on cell proliferation and cell cycle progression using CCK-8 assay and flow cytometry assay. Result: In our proteomic analysis of GC tissues, 569 proteins were differentially expressed, with 248 up-regulated and 321 down-regulated. GO enrichment, KEGG pathway, and cluster analysis linked them to key pathways like cell proliferation and immune response.Nine promising proteins were screened by proteomics analysis and validated using PRM, DDX39A was recognized as the critical functional protein. IHC further demonstrated DDX39A was high expressed in GC, and its expression was correlated with N stage and TNM stage. The knockdown of DDX39A significantly reducing the proliferation and survival of GC cell lines, as confirmed by RT-qPCR and Western blot. Additionally, cell cycle analysis showed an increase in the G1 phase and a decrease in the S phase after knockdown. That highlighted DDX39A's critical role in GC cell cycle regulation and growth. Conclusion: In this study, a series of differentially expressed proteins were successfully identified using proteomic analysis, and DDX39A was identified as a key proliferation-promoting protein in GC. DDX39A is potential to be a therapeutic target for GC and further research into it would be worthwhile.