Zinc inhibits nuclear factor-κB activation and sensitizes prostate cancer cells to cytotoxic agents

Prostate carcinogenesis involves transformation of zinc- accumulating normal epithelial cells to malignant cells, which do not accumulate zinc. In this study, we demonstrate by immunoblotting and immunohistochemistry that physiological levels of zinc inhibit activation of nuclear factor (NF)-κB transcription factor in PC-3 and DU-145 human prostate cancer cells, reduce expression of NF-κB-controlled antiapoptotic protein c-IAP2, and activate c-Jun NH₂-terminal kinases. Preincubation of PC-3 cells with physiological concentrations of zinc sensitized tumor cells to tumor necrosis factor (TNF)-α, and paclitaxel mediated cell death as defined by terminal deoxynucleotidyl transferase-mediated nick end labeling assay. These results suggest one possible mechanism for the inhibitory effect of zinc on the development and progression of prostate malignancy and might have important consequences for the prevention and treatment of prostate cancer.