Figure 5. HuR antagonizes the downregulation of COX-2 expression caused by miR-16 in hepatoma cell lines.

WRL68 cell extracts (500 µg per lane) were immunoprecipitated with HuR or IgG antibodies. Bound RNA was harvested with TRIzol reagent, reverse transcriptased, and PCR amplified with COX-2 (A) or miR-16 primers (B). PCR products were visualized by electrophoresis in SYBR Safe DNA gel stain agarose gels. The abundance of the transcripts present in WRL68 cells after HuR immunoprecipitation was assessed, and fold differences were plotted. Input, total mRNA in cell extract; unbound, unbound mRNA after immunoprecipitation with HuR antibody; bound, bound mRNA after immunoprecipitation with HuR antibody; and control, bound mRNA after immunoprecipitation with IgG antiboby. (C–D) WRL68 and Hep3B cell lines were transfected with miR-16 or In-miR-16 (50 nM). COX-2 and HuR protein levels were analyzed by Western Blot. (E–F) WRL68 and Hep3B cell lines were cotransfected with miR-16 (50 nM) and pcDNA3-HuR-GFP expression vector (4 µg). COX-2 and HuR protein levels were analyzed by Western Blot. Data are reported as means±SD of three independent experiments. *p< 0.05 vs. the control condition and # p< 0.05 vs. the miR-16 transfection condition.