Carbonic anhydrase IV inhibits cell proliferation in gastric cancer by regulating the cell cycle.

Carbonic anhydrase IV (CA4) is silenced in colorectal cancer. However, the effect of CA4 on the development of gastric cancer (GC) is poorly understood. The present study aimed to determine the role of CA4 in GC tumorigenesis and its underlying molecular mechanism. The levels of CA4 in GC cells and tissues were evaluated by reverse transcription-quantitative PCR and immunohistochemistry. CA4 expression was suppressed in GC cells and tissues compared with adjacent healthy tissues and normal human gastric epithelial cells, respectively. This reduced expression was significantly associated with tumor size, invasion and differentiation. Analyses with a real-time cell analyzer and clonogenic assays were conducted to validate the impact of CA4 on GC cell lines (AGS and HGC-27) and normal human gastric epithelial cell line (GES-1) proliferation. The effects of CA4 on the cell cycle in GC cells were determined by flow cytometry. The levels of CA4 and cell cycle-associated proteins were confirmed by western blotting. CA4 overexpression inhibited GC cell proliferation and reduced colony-forming ability, arrested the cell cycle in the G2/M phase, inhibited cyclin B1 and cyclin-dependent kinase 2 expression and induced p21 expression. These results indicate that CA4 may serve an important role in GC tumorigenesis by inhibiting cellular proliferation via regulating the expression of cell cycle-associated proteins. CA4 may serve as a diagnostic biomarker and a potential therapeutic target in GC.