Effects of fluoride exposure on microRNA-200c expression and its target in human osteoblast Saos-2 cells

Objective To investigate the effect of fluoride exposure on expression of miRNA(miR)-200c and its target in human osteoblast Saos-2 cells. Methods Saos-2 cells were cultured in DMEM/F-12 medium and treated with fluoride (sodium fluoride, NaF). There were two groups including: control group (0 mg/L) and fluoride group (4 mg/L). Cells were harvested after 48 hours of culture with fluoride. The expression of miR-200c, the mRNA of alkaline phosphatase (ALP), osteocalcin (BGP), the target phosphatase and tensin homolog deleted on chromosome ten (PTEN) and dual-specific phosphatase 1(DUSP1) of miR-200c was detected by qRT-PCR. The protein expression of PTEN and DUSP1 was detected by Western blotting. Results The expressions of ALP, BGP mRNA and miR-200c in Saos-2 cells in the fluoride group (23.60 ± 1.87, 9.41 ± 0.94, 8.61 ± 0.26) were higher than those in the control group (1.00 ± 0.11, 1.00 ± 0.07, 1.00 ± 0.12). The differences were statistically significant (t=- 24.084, - 18.388, - 8.687, P < 0.05). The mRNA expressions of PTEN and DUSP1 in the fluoride group (0.63 ± 0.02, 0.38 ± 0.02) were lower than those in the control group (1.02 ± 0.24, 1.02 ± 0.24). The differences were statistically significant (t=3.327, 5.454, P < 0.05). The protein expressions of PTEN and DUSP1 in Saos-2 cells in the fluoride group (1.19 ± 0.10, 0.83 ± 0.07) were lower than those in the control group (1.81 ± 0.14, 1.44 ± 0.25). The differences were statistically significant (t=6.250, 4.171, P < 0.05). Conclusion Exposure to fluorine may increase the expression of miR-200c in Saos-2 cells, and fluorine may act on PTEN and DUSP1 through miR-200c, downregulates the mRNA and protein expression levels of PTEN and DUSP1. Key words: Fluorine; Human osteoblast Saos-2 cells; MicroRNA-200c; PTEN; DUSP1