去泛素化酶USP38通过稳定RBM14促进胃癌进展的机制研究OA

Objective·To investigate the expression characteristics and clinical prognostic value of the deubiquitinating enzyme ubiquitin-specific peptidase 38(USP38)in gastric cancer,as well as its pro-oncogenic molecular mechanism,and to identify the downstream key target RNA-binding motif protein 14(RBM14).Methods·Tumor and adjacent non-tumor tissue specimens were collected from 50 patients with gastric cancer who underwent surgical treatment at the Department of Gastrointestinal Surgery,Shanghai General Hospital,Shanghai Jiao Tong University School of Medicine.Quantitative real-time PCR and Western blotting were used to verify the expression of USP38 in gastric cancer,and data from The Cancer Genome Atlas(TCGA)and Gene Expression Omnibus(GEO)were used to analyze the correlation between the clinical characteristics of patients with gastric cancer and USP38 expression levels.Gene Set Enrichment Analysis(GSEA),Gene Ontology(GO),and Kyoto Encyclopedia of Genes and Genomes(KEGG)analyses were performed to predict USP38-related signaling pathways.Potential substrates of USP38 were screened by combining published literature with the results of Pearson correlation analysis.The effects of USP38 on the proliferation and migration of AGS and HGC-27 gastric cancer cells were assessed using the cell counting kit-8(CCK-8),5-ethynyl-2'-deoxyuridine(EdU)assay,colony formation assay,and wound healing assay.A stable knockdown cell line was constructed using lentiviral vectors carrying short hairpin RNA(shRNA)targeting USP38,and functional rescue experiments were performed to validate the biological function of the USP38-RBM14 regulatory axis.Results·TCGA data analysis showed that USP38 was significantly highly expressed in gastric cancer tissues(P<0.001),and its expression level was positively correlated with shorter overall survival(log-rank P<0.001,HR=1.36)and pathological stage(P=0.017).GSEA analysis revealed that the high-USP38-expression group was significantly enriched in the G2/M checkpoint,early 2 factor(E2F)targets,nuclear speckles,and DNA damage repair pathways(all adjusted P value<0.001),and knockdown of USP38 downregulated the expression of proliferation-and mesenchymal-related markers.Functional experiments confirmed that USP38 knockdown significantly inhibited the proliferation and migration of gastric cancer cells(P<0.05).Pearson correlation analysis revealed that the expression levels of USP38 and its potential binding protein RBM14 were significantly positively correlated(R=0.22,P<0.001).Further studies revealed that USP38 knockdown decreased RBM14 protein levels,and experiments with a proteasome inhibitor and cycloheximide(CHX)indicated that USP38 stabilized RBM14 at the post-translational level.Functional rescue experiments showed that RBM14 overexpression partially reversed the inhibitory effect of USP38 knockdown on gastric cancer cells,confirming that USP38 promoted gastric cancer progression by stabilizing RBM14 protein.Conclusion·USP38 is highly expressed in gastric cancer and is associated with poor patient prognosis;knocking down USP38 can inhibit the proliferation and migration of gastric cancer cells.USP38 exerts an oncogenic effect by stabilizing the RBM14 protein.