Inhibition of the STAT3 nuclear translocation by Compound 1 in HeLa cells.

<p>(A) Fluorescence images of the STAT3 proteins in the nuclei of HeLa cells. The HeLa cells were pretreated with or without the test compounds, and then either treated with oncostatin M or left untreated. The cell nuclei were stained with Hoechst 33342 and the STAT3 proteins were visualized with anti-STAT3 antibody. The merged image showed the fusion of blue (nuclei) and green (STAT3) fluorescence. The test compounds treated are shown in the figure. The cells treated with neither oncostatin M nor the test compounds are shown as “–oncostatin M”. (B) Dose-dependent inhibition of the STAT3 nuclear translocation by Compound <b>1</b>. The mean fluorescent values of STAT3 in the nuclei were calculated. The signals with oncostatin M but not the test compounds (“vehicle”) and “–oncostatin M” were used for the 100% and 0% signals, respectively. The relative signal intensity was calculated in each well. Each point represents the mean from three replicates, and the error bars represent the standard deviation from the mean (*<i>P</i><0.05 and **<i>P</i><0.01 versus vehicle in Student’s <i>t</i>-test). JAK inhibitor 1 was used as a positive control.