Abstract: Objective To investigate the potential biological functions of miR-30c in osteosarcoma(OS) cells.
Methods RT-PCR was used to detect the expression of miR-30c in seven cell lines. The candidate cells were divided into 3 groups: the mock group, the negative group(NC) and miR-30c overexpression group(miR-30c mimic). Colony formation and CCK-8 assays were used to the detect the changes in cell proliferation after transfection. Flow cytometry was used to detect the effect of miR-30c on cell apoptosis in candidate OS cell. Transwell invasion and migration assays were conducted to assess the effects of miR-30c on cell metastasis capabilities in vitro after transfection. Subcutaneous tumor formation assay in nude mice was used to confirm the effect of miR-30c on OS cell proliferation in vivo.
Results The expression of miR-30c in U2OS, Saos2, Mg63, HuO9, KIKU, 143B cell lines were significantly lower than in hFOB1.19 while U2OS cells have the biggest fold changes with hFOB1.19(P＜0.05). The miR-30c mimic group had fewer cell clones than the mock group and NC group(P＜0.05). The cell proliferation ability of each group showed an increasing trend, the cell proliferation ability of miR-30c mimic group was significantly lower than the other groups, which had statistically significant differences in interactions between groups, time points and group·time points(P＜0.05). The apoptosis rate of U2OS cells in the miR-30c mimic was significantly higher than that in the mock group and NC group(P＜0.05). The capacity of cell invasion and migration were significantly suppressed in U2OS after transfection with miR-30c mimics when compared with NC group(P＜0.05). After 4 weeks of subcutaneous tumor implantation in nude mice, the volume and weight of transplanted tumors in miR-30c mimic group were significantly smaller than those in mock group and NC group(P＜0.05).
Conclusion miR-30c may be involved in the proliferation and metastasis of U2OS as a tumor suppressor gene.

Key words: osteosarcoma, microRNAs, biological functions