Effect of microRNA-155 on proliferation of osteosarcoma cells in vitro

Objective To explore the effects of microRNA-155 (miR-155) expression on growth of osteosarcoma cells and the action mechanism. Methods Normal osteoblasts served as the control group and osteosarcoma cells as the experimental group. MiR-155 levels were examined by real-time quantitative polymerase chain reaction (Real-time PCR). The effects of miR-155 on proliferation of osteosarcoma cells and apoptosis were detected by cell counting kit-8 (CCK-8) and flow cytometry assays respectively. Real-time PCR and Western blotting were applied to investigate the target gene of miR-155 in osteosarcoma cells. T test was used for comparison between the two groups, and anova was used for comparison between multiple groups, P<0.05 was considered to be statistically significant. Results MiR-155 expression was significantly up-regulated in osteosarcoma cells (U2OS, Saox-2 and MG-63) (5.10±0.32, 6.82±0.48 and 10.12±0.39) as compared with their matched normal parts (1.01±0.13, t=13.100, P<0.01). CCK-8 indicated that, compared with the negative control group (0.37±0.02, 0.58±0.02, 0.80±0.04), the A values of MG-63 cells were 0.49±0.03, 0.77±0.03, 0.93±0.02, respectively, at 48, 72 and 96 h after transfection with miR-155, and their proliferation capacity was significantly enhanced (t=11.200, P<0.05). Moreover, 48 h after transfeetion, the apoptosis rate of MG-63 cells in miR-155 treatment group was (0.90±0.13)%, significantly lower than in miR-control group [(5.92±0.80)%, t=17.900, P<0.05]. Conclusion Our data revealed that miR-155 may function as an oncogene in osteosarcoma development and it may also provide a therapeutic strategy for controlling osteosarcoma progression. Key words: Osteosarcoma; MicroRNA-155