Fig. 4.

Cox-2-dependent H₂O₂ generation in WPMY-1 cells inhibits DU145 cell response to SMIF. A, CM loses its inhibitory effect on DU145 motility at concentrations of H₂O₂ greater than or equal to 10 μm. CM was generated as previously described from WPMY-1 cells. Naïve DU145 cells were wounded, and the media were replaced with CM to which varying amounts of H₂O₂ had been added. Data represent the mean of six independent experiments ± sem. A one-way ANOVA followed by Tukey's multiple comparison test was performed. **, P < 0.01 relative to appropriate control media. B, Addition of H₂O₂ (10 μm) to the DU145/SH4 coculture reverses the motility inhibition observed under basal conditions. A modified wound-healing assay as previously described was carried out with and without the addition of H₂O₂. Data represent the results of four independent experiments ± sem. A one-way ANOVA followed by Tukey's multiple comparison test was performed. *, P < 0.05 relative to appropriate DU145 control. C, CM was incubated with 10 μm H₂O₂ for 3 h. After this pretreatment, a portion of the media was then treated with catalase (1500 U/ml), and the two different treatment groups were added to wounded naïve DU145 cells. Data represent three independent experiments ± sem. A one-way ANOVA followed by Tukey's multiple comparison test was performed. *, P < 0.05 compared with all other conditions.