High Expression of Annexin A9 Promotes Cell Proliferation and Migration in Gastric Cancer via the TGF-β Signaling Pathway

Annexin A9 (ANXA9) represents an important calcium-dependent phospholipid-binding protein family member and contains a calcium-binding site that is necessary for extracellular matrix proteins. ANXA9 has a significant role in human cancers. However, there is no correlation study existing on ANXA9 in gastric cancer (GC). ANXA9 messenger RNA (mRNA) expression within patients with GC were detected with reverse transcription polymerase chain reaction and its protein expression in GC and GES-1 cells were detected through Western blotting. ANXA9 levels within normal and GC tissue samples were measured by Kaplan-Meier analysis and Oncomine. Transwell migration, colony formation, and cell cycle assay monitored the effects of ANXA9 on cell proliferation and metastasis and growth. Additionally, proteins related to epithelial-mesenchymal transition (EMT) were detected to evaluate the function of ANXA9 within GC cells. Relative to GES-1 cells, ANXA9 expression increased within GC cells. Also, ANXA9 expression increased in GC tissues and indicated an unfavorable prognosis. Furthermore, ANXA9 over-expression within HGC-27 cells increased migrated cells quantity and formed larger and more numerous cell clones; the G1 phase decreased while S and G2 phases increased; whereas ANXA9 knockdown suppressed MGC-803 cell growth and migration. Thus, ANXA9 may influence cell growth, migration and EMT through transforming growth factor β (TGF-β) signal transduction pathway. Immunofluorescence analyzed SMAD2/3 and p-SMAD2/3 distribution and expression when ANXA9 was overexpressed in HGC-27 cells. These results predicted that ANXA9 mediated cell migration and growth through TGF-β signal transduction pathway within GC.