Marine toxin domoic acid induces moderate toxicological response in non-target HepG2 cells

Domoic acid (DA) is a marine neurotoxin produced as a defence compound by diatom Pseudo-nitzschia. Although its toxicity is well known in marine mammals and fish, data on DA cyto/genotoxicity in human non-target cells is still limited. Hence, we aimed to study the effect of DA (0.001-10 µg/mL) on cell viability and proliferation kinetics of human hepatocellular carcinoma (HepG2) cells as well as DNA damage induction after 4, 24 and 72 h of exposure. The results revealed that DA up to 10 µg/mL did not elicit significant changes in HepG2 cell viability, proliferation and cell cycle at applied conditions. DA did not generate DNA double-strand breaks, while it exhibited significant dose- and time-dependent increase of DNA damage in the form of either DNA single-strand breaks or alkali labile sites. Additionally, increased malondialdehyde level after DA treatment indicated oxidative damage to lipids. Altogether, the results showed that neurotoxin DA induced only minor adverse genotoxic effects in non-target HepG2 cells that most probably occurred resulting from the oxidative stress. However, additional research is needed to further elucidate the mechanisms of DA toxicity, particularly in terms of chronic exposure, as well as to understand its potential influence on human non-target cells.