MicroRNA-99a promotes cell proliferation, migration and invasion in gastric cancer by modulating c-Src

Background: Recent studies have shown that microRNA-99a(miR-99a)plays a key role in the development of virious malignancies; however, its relationship with gastric cancer remains unclear. In this study, we investigated the functions and potential mechanisms of miR-99a in gastric cancer. Methods: Real-time qRT-PCR was used to assess the expression levels of miR-99a in gastric cancer tissue samples and cell lines compared to their matched adjacent normal tissues and a normal gastric mucosa epithelial cell line, respectively. SGC-7901 cells were transfected with miR-99a mimics and negative controls to determine the effects of miR-99a overexpression on cell proliferation, cell cycle transition, migration and invasion of gastric cancer cells in vitro . The role of miR-99a in endogenous c-Src expression in gastric cancer cells was also investigated by qRT-PCR and Western blotting. Results: Our results showed a significant increase in miR-99a expression in both gastric cancer tissues and cells compared to normal tissues and cells. Overexpression of miR-99a significantly promoted the cell proliferation, migration and invasion of gastric cancer cells compared to normal cells, with a concurrent increase in the S+G2 phases of the cell cycle. Further investigations found that miR-99a overexpression led to significant upregulation of endogenous c-Src. Conclusion: Taken together, our findings suggest that miR-99a may act as a tumour promoter in the pathogenesis of gastric cancer by indirectly modulating c-Src expression.