Differential Response of Normal (PrEC) and Cancerous Human Prostate Cells (PC-3) to Phenethyl Isothiocyanate-Mediated Changes in Expression of Antioxidant Defense Genes

The present study was undertaken to test a hypothesis that differential sensitivity of normal and cancerous human prostate cells to prooxidant effect of phenethyl isothiocyanate (PEITC) is determined by altered expression of antioxidant defense genes. Prooxidant effect of PEITC was assessed by flow cytometry using a chemical probe and measurement of hydrogen peroxide production. Gene expression was determined by real-time PCR using Human Oxidative Stress and Antioxidant Defense RT2 Profiler (TM). Protein expression was determined by Western blotting. The PEITC treatment resulted in generation of reactive oxygen species and hydrogen peroxide production in PC-3 human prostate cancer cells but not in a representative normal human prostate epithelial cell line (PrEC). Basal oxidative stress-antioxidant defense gene expression signature was strikingly different between PC-3 and PrEC cells. The PEITC treatment (2.5 mu M, 6 h) caused up-regulation of 29 genes and down-regulation of 2 genes in PC-3 cells. Conversely, 4 genes were up-regulated, and 10 genes were down-regulated by a similar PEITC treatment in the PrEC cell line. Differential sensitivity of PC-3 versus PrEC cells to prooxidant effect of PEITC is likely attributable to difference in basal as well as altered expression of antioxidant defense genes.