miR-200a Inhibits Tumor Proliferation by Targeting AP-2γ in Neuroblastoma Cells

Background: MicroRNA-200a (miR-200a) has been reported to regulate tumour progression in several tumours but little is known about its role in neuroblastoma. Our aim was to investigate the potential role and mechanism of miR-200a in neuroblastomas. Materials and Methods: Expression levels of miR-200a in tissues were determined using RT-PCR. The effect of miR-200a and shAP-$2{\gamma}$ on cell viability was evaluated using MTS assays, and target protein expression was determined using Western blotting and RT-PCR. Luciferase reporter plasmids were constructed to confirm direct targeting. Results were reported as mean${\pm}$S.E.M and differences were tested for significance using the 2-tailed Students t-test. Results: We determined that miR-200a expression was significantly lower in neuroblastoma tumors than the adjacent non-cancer tissue. Over-expression of miR-200 are reduced cell viability in neuroblastoma cells and inhibited tumor growth in mouse xenografts. We identified AP-$2{\gamma}$ as a novel target for miR-200a in neuroblastoma cells. Thus miR-200a targets the 3'UTR of AP-$2{\gamma}$ and inhibits its mRNA and protein expression. Furthermore, our result showed that shRNA knockdown of AP-$2{\gamma}$ in neuroblastoma cells results in significant inhibit of cell proliferation and tumor growth in vitro, supporting an oncogenic role of AP-$2{\gamma}$ in neuroblastoma. Conclusions: Our study revealed that miR-200a is a candidate tumor suppressor in neuroblastoma, through direct targeting of AP-$2{\gamma}$. These findings re-enforce the proposal of AP-$2{\gamma}$ as a therapeutic target in neuroblastoma.