Overexpression of Bmi-1 induces the malignant transformation of gastric epithelial cells in vitro.

Oncogene Bmi-1 (B-cell-specific Moloney murine leukemia virus integration site 1) has attracted much attention for its involvement in the initiation of a variety of tumors. Our previous study showed that Bmi-1 was highly expressed in gastric cancer and correlated with patient prognosis. However, whether aberrant Bmi-1 expression was critical for the transformation of gastric epithelial cells remains unknown. In this study, we stably expressed Bmi-1 in a human gastric epithelial immortalized cell line, GES-1. The overexpression of Bmi-1 promoted cell growth and proliferation, inhibited apoptosis, enhanced clone formation capability, possessed the characteristics of anchorage-independent growth, and increased migration and invasion abilities. Therefore, our findings demonstrated that ectopic expression of Bmi-1 played an important role in the malignant transformation of gastric epithelial cells.