Research On Radiosensivity And Proliferation Of Nasopharyngeal Carcinoma Cells In Which HIF1α And Survivin Silenced By MicroRNA Mediated With Nano-transport System

Objective: mi RNA-HIF-1α and mi RNA-Survivin plasmids coated with PEI-Fe3O4 nanoparticles were transfected into nasopharyngeal carcinoma cells(CNEII) in order to inhibit cell growth via improving radiosensitivity of cells, by which break a new ground on the research on radiosensitivity therapy in nasopharyngeal carcinoma and provide a new choice of carrier in gene transfection. Methods: Design and synthesize mi RNA-HIF-1α and mi RNA-Survivin plasmids. Magnetic nanoparticles Fe3O4 coated with covalently-bound biofunctional polyethyleneimine(PEI) was prepared. Size and morphology of PEI-Fe3O4 nanoparticles were observed by scanning electronic microscope. mi RNA-HIF-1α and mi RNA-Survivin plasmids coated with PEI-Fe3O4 plasmids were transfected to CNEII cells. Transfection efficiency was measured by fluorescence microscope. Protein expressions were detected by western blot and m RNAs were detected by real time RT-PCR. Cell proliferation was detected by MTT. Apoptotic rates were evaluated via flow cytometry. Results: PEI-Fe3O4 nanoparticels were successfully constructed. The transfection efficiency of group H, group S, group HS was 55.3%±6.5%, 48.1%±2.3%,c46.6%±4.1%. The suppression ratio of m RNA of HIF-1α in group H and group HS was 69% and 84% and the suppression ratio of protein of HIF-1α in group H and group HS was 69.4% and 73.3%. The suppression ratio of m RNA of Survivin in group S, group HS was97%, 93% and the suppression ratio of protein of Survivin in group S and group HS was 82.5% and 65%. Cell apoptosis of group S and group HS after transfection was 1.97 and 1.46 times more to group NC, respectively. After exposure to radiation, apoptosis of group H, group S and group HS after transfection was 4.00, 3.40 and 3.67 times to group NC, respectively. The differences of apoptosis and cell proleration in group HS were not significant compared to group H and group S. Conclusion: mi RNA-HIF-1α and mi RNA-Survivin plasmids have successfully transfected into CNEII cells and inhibited target genes on both molecular and protein level. Proliferation of transfected cells was inhibited while apoptosis was increased. The increase of cell apoptosis of transfected cells was even more obvious when exposure to radiation.