Abstract
BACKGROUND AND OBJECTIVE: Recent studies suggest that miR-155 is involved in lung tumorgenesis, whereas the precise mechanism has not yet been characterized. The aim of this study is to investigate the effects of over-expression of miR-155 on the growth of human lung cancer 95D cells in vitro and its possible mechanism, and thus to provide experimental evidence for further researching on the role of miR-155 in the pathogenesis and development of lung cancer. METHODS: miR-155 mimics control and miR-155 mimics were tranfected into human lung cancer 95D cells by FuGENE®HD Transfection Reagent respectively in vitro. The relative expression level of miR-155 in 95D cells was determined using specific probe of real-time PCR after transfection. The proliferation of 95D cells was detected by MTT assay. The cell cycle was analyzed by flow cytometry. The expression of SOS1 protein was measured by Western blot. RESULTS: Compared with control groups, the expression level of miR-155 was significantly increased in miR-155 mimics transfected group (P<0.05). The proliferation of miR-155-transfected 95D cells was significantly inhibited (P<0.05). The percentage of G0/G1 phase cells was increased significantly in miR-155-transfected 95D cells, while the percentage of S phase was remarkably reduced (P<0.05). Furthermore, the expression of SOS1 in miR-155-transfected 95D cells was significantly down-regulated (P<0.05). CONCLUSIONS: miR-155 could significantly inhibit the growth of human lung cancer 95D cells in vitro, which might be closely related to miR-155 induced G0/G1 phase arrest.