Acetochlor is a high-volume
herbicide used on a global scale and toxicity assessments are needed to define its potential for adverse effects in wildlife and humans. This study was conducted to determine the effects of
acetochlor on human liver
carcinoma cells (HepG2), a cell model widely used to assess the potential for chemical hepatotoxicity. Experiments were conducted at concentrations ranging 0-800 μM
acetochlor over a 12 to 48h period to quantify underlying mechanisms of toxicity. Our data indicate that
acetochlor suppressed HepG2 cell proliferation in both a concentration- and time-dependent manner.
Acetochlor induced
reactive oxygen species (ROS) generation more than 700% with exposure to 400 μM
acetochlor, and
acetochlor decreased the activities and levels of
anti-oxidant responses (
superoxide dismutase,
glutathione) following exposure to 100 μM, 200 μM and 400 μM
acetochlor.
Acetochlor also (1) induced HepG2 cell damage through apoptotic-signaling pathways; (2) enhanced intracellular free Ca2+ concentration (>400%); (3) decreased mitochondrial transmembrane potential (∼77%), and reduced
ATP levels (∼65%) following exposure to 400 μM
acetochlor compared to untreated cells. Notably, cell cycle progression was blocked at G0/G1 phase in HepG2 cells when treated for 24 h with 400 μM
acetochlor. Taken together,
acetochlor induced significant cytotoxicity toward HepG2 cells, and the underlying toxicity mechanisms appear to be related to ROS generation,
mitochondrial dysfunction and disruption in the cell cycle regulation. These data contribute to toxicity assessments for
acetochlor, a high-use
herbicide, to quantify risk to wildlife and human health.