Zinc functions as a cytotoxic agent for prostate cancer cells independent of culture and growth conditions.

The effects of zinc on the viability of PC3, LNCaP and DU145 prostate cancer cell lines in vitro were examined. The data indicate that, despite their distinctly different gene expression profiles, morphology and tissue origin, all cell lines responded to zinc in a similar time and dose dependent manner. Experiments using pyrithione indicated that cell death is mediated by internalized zinc. Zinc effects on cells plated as monolayers were compared to its effects on cells plated in a collagen matrix. Although the rate of cell growth in the matrix was delayed compared to cells in 2-dimensional cultures, the cytotoxic effects of zinc were unaltered. Using both 2-dimensional and 3-dimensional cultures, we observed that zinc cytotoxicity was independent of both the culture conditions and the rate of cell growth, results that contrast the activity of the current chemotherapeutics used to treat prostate cancer. The attractive properties of zinc cytotoxicity demonstrated in this paper suggest that is can be developed as a novel and effective chemotherapeutic agent for prostate cancer treatment.