Abstract: Objective To investigate whether miR-200a suppresses cell proliferation by targeting AP-2γ expression, and reveal molecular mechanism that miR-200a functions as a tumor-suppressor in neuroblastoma cells. Methods Dualluciferase reporter gene assay was employed to examine the effect of miR-200a on AP-2γ promotor luciferase activity. Neu⁃ roblastoma cells were transfected with miR-200a mimics, and the expressions of AP-2γ mRNA and protein were detected by RT-PCR and Western blot assay. The effects of AP-2γ down-regulation on cell proliferation were observed after AP-2γ shRNA was transfected into neuroblastoma cells. Neuroblastoma cell proliferation was detected by MTS assay after being cotransfected with miR-200a mimics and AP-2γ plasmid. Results Results showed that miR-200a could inhibit proliferation of neuroblastoma cells at cell viability (66.33±5.13) compared with that of control group (100±0), and also miR-200a can bind to the 3′untranslated region of AP -2γ promotor and inhibit its luciferase activity with an inhibit ratio at (0.624±0.051). AP-2γ mRNA and protein expressions were significantly down-regulated when miR-200a was over-expressed in neuroblas⁃ toma cells. Furthermore, results showed that shRNA-mediated down-regulation of AP-2γ that suppressed the cell prolifera⁃ tion of neuroblastoma at (62.5±2.4) by comparing with the control group (100±0). Moreover, restoring AP-2γ expression re⁃ versed the effect of miR-200a with a cell viability suppression at (92.4±1.4). Conclusion miR-200a suppresses cell prolif⁃ eration by targeting AP-2γ expression in neuroblastoma cells.

Key words: neuroblastoma, microRNAs, cell proliferation, AP-2γ, miR-200a