Induction of cell death, DNA strand breaks, and cell cycle arrest in DU145 human prostate carcinoma cell line by benzo[a]pyrene and benzo[a]pyrene-7,8-diol-9,10-epoxide.

Benzo[a]pyrene (B[a]P), a polycyclic aromatic hydrocarbon, is a major environmental pollutant. In this study, the effects of this carcinogen/mutagen and one of its metabolites, benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE), on human prostate carcinoma cell line DU145, were examined. Cell viability, DNA damage, and cell cycle progression were evaluated as toxic end-points. We have shown that B[a]P and BPDE inhibited cell viability following 48 hr of exposure. Furthermore, comet assay analyses revealed that both B[a]P and BPDE induced DNA strand breaks in a concentration-dependent fashion. Flow cytometric analyses showed that about 70% of DU145 cells were arrested by B[a]P at the G1 phase, while about 76% were arrested at G1 phase by BPDE. These data reveal that B[a]P and BPDE are cytotoxic and genotoxic to DU145 prostate cancer cells.