ABSTRACT
@# Objective: To investigate the expression of histone methyltransferase G9a in gastric cancer tissues and its correlation to prognosis, and to observe the effect of G9a inhibitor on the proliferation and apoptosis of gastric cancer cells. Methods: The expression level of G9a in gastric cancer tissues and its correlation to prognosis were analyzed by using the Kaplan-Meier Plotter and Oncomine database. Human gastric cancer cell line SGC-7901 and MKN-45 were selected as study subject. The expression level of G9a protein was detected by Western blotting. The morphological change of gastric cancer cells after the treatment of G9a inhibitor BIX01294 was observed. CCK-8 proliferation experiment and plate colony formation assay were used to examine the proliferation ability and clone formation rate of gastric cancer cells. The changes of cell apoptosis were detected by Annexin-V staining. Results: G9a was highly expressed in gastric cancer tissues (P<0.01), and the high expression of G9a was positively correlated with poor prognosis of gastric cancer patients (P<0.01). After the treatment of BIX01294, the morphology of gastric cancer cells was changed, the volume of gastric cancer cells reduced, the intercellular connections disappeared, and even the apoptotic manifestations appeared, such as the shrinking,, becoming round and cast-off etc. BIX01294 could significantly inhibit the proliferation and colony formation but promote the apoptosis of gastric cancer cells (all P<0.05). Conclusion: Histone methyltransferase G9a was highly expressed in gastric cancer tissues, and its high expression level was positively correlated with poor prognosis. The proliferation of gastric cancer cells was obviously inhibited while the apoptosis was significantly promoted after inhibiting G9a expression.