Diuron is a substituted phenylurea used as a
herbicide to control broadleaf and grass weeds and as a biocidal antifouling agent.
Diuron is carcinogenic in rat urinary bladder and toxic to the reproductive system of oysters, sea urchins and lizards. The few studies carried out in human cells do not include the genotoxicity of
diuron. We have investigated the toxicity of
diuron in human breast
adenocarcinoma (MCF-7) and human placental
choriocarcinoma (BeWo) cells. The production of
reactive oxygen species (ROS) was statistically significantly increased in both cell lines but only at the highest 200 μM concentration.
Diuron clearly reduced the viability of BeWo, but not MCF-7 cells. The relative cell number was decreased in both cell lines indicative of inhibition of cell proliferation. In the Comet assay,
diuron increased DNA fragmentation in MCF-7 but not in BeWo cells. The expressions of p53
protein, a marker for cell stress, and p21
protein, a transcriptional target of p53, were increased, but only in MCF-7 cells. In conclusion, our results suggest that
diuron is cytotoxic and potentially genotoxic in a tissue-specific manner and that ROS play a role in its toxicity. Thus, exposure to
diuron may exert harmful effects on fetal development and damage human health.