[SF3B3 overexpression promotes proliferation of gastric cancer cells and correlates with poor patient prognosis].

[OBJECTIVES] To investigate the role of SF3B3 in gastric cancer (GC) progression and prognosis and its possible mechanisms.

[METHODS] SF3B3 expression levels in pan-cancer and GC were analyzed using TIMER2.0, GEPIA, and UALCAN databases and validated using immunohistochemistry in GC tissues. Survival curves of GC patients were established using Kaplan-Meier Plotter and the data of a patient cohort our hospital. The independent risk factors for 5-year postoperative survival were identified using Cox regression, and their predictive values were evaluated using ROC analysis. SF3B3-associated biological processes were predicted by bioinformatics enrichment analyses. In GC HGC-27 cells, the effects of lentivirus-mediated SF3B3 knockdown and overexpression on cell proliferation and migration were investigated, and the changes in the key glycolytic proteins and extracellular acidification rate (ECAR) were detected. The influence of SF3B3 expression level on tumorigenesis and glycolytic protein expression were evaluated in a nude mouse xenograft model.

[RESULTS] High expression of SF3B3 in GC was associated with poor patient prognosis (<0.05). The factors affecting 5-year survival outcomes following gastric oncological resection included high SF3B3 expression, a CEA level ≥5μg/L, a CA19-9 level ≥37 kU/L, tumor stage T3-4, and lymph node metastasis stage N2-3 (<0.05). Bioinformatics analysis showed significant enrichment of SF3B3 in glycolysis. In HGC-27 cells, SF3B3 knockdown significantly inhibited while SF3B3 overexpression enhanced cell proliferation, migration, and invasion. SF3B3 knockdown obviously decreased the expressions of HK2, PKM2 and LDHA proteins and ECAR in HGC-27 cells, whereas SF3B3 overexpression produced the opposite effect. In nude mouse xenograft models, SF3B3 knockdown significantly reduced tumor mass and downregulated expression of HK2, PKM2 and LDHA proteins, and SF3B3 overexpression induced the opposite changes.

[CONCLUSIONS] SF3B3 overexpression is associated with poor prognosis of GC patients and promotes GC cell proliferation, migration and invasion possibly by enhancing glycolysis.