Cordier, WernerYousaf, MuhammadNell, Margo JudithSteenkamp, Vanessa2021-12-072021-04Cordier, W., Yousaf, M., Nell, M.J. et al. 2021, 'Underlying mechanisms of cytotoxicity in HepG2 hepatocarcinoma cells exposed to arsenic, cadmium and mercury individually and in combination', Toxicology in Vitro, vol. 72, art. 105101, pp. 1-8.0887-2333 (print)1879-3177 (online)10.1016/j.tiv.2021.105101http://hdl.handle.net/2263/82988BACKGROUND : Toxicity data regarding combinational exposure of humans to arsenic, cadmium and mercury is scarce. Although hepatotoxicity has been reported, limited information is available on their mechanistic underpinnings. The cytotoxic mechanisms of these metals were determined in HepG2 hepatocarcinoma cell lines after individual and combinational exposure. METHODS : HepG2 cells were exposed to heavy metals (sodium arsenite, cadmium chloride, and mercury chloride) individually or in combination for 24 h, after which cell density, mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS), reduced glutathione (GSH), adenosine triphosphate (ATP) and caspase-3/7 activity was assessed. RESULTS AND DISCUSSION : Cadmium (IC50 = 0.43 mg/L) and the combination (0.45 mg/L, arsenic reference) were most cytotoxic, followed by arsenic (6.71 mg/L) and mercury (28.23 mg/L). Depolarisation of the ΔΨm and reductions in ROS, GSH and ATP levels occurred. Arsenic, cadmium and the combination increased caspase-3/7 activity, while mercury reduced it. CONCLUSION : The combination produced a greater, albeit mechanistically similar, cytotoxicity compared to individual metals. Cytotoxicity was dependent on altered mitochondrial integrity, redox-status, and bioenergetics. Although the combination's cytotoxicity was associated with caspase-3/7 activity, this was not true for mercury. Heavy metal interactions should be assessed to elucidate molecular underpinnings of cytotoxicity.en© 2021 Elsevier Inc. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Toxicology in Vitro. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in Toxicology in Vitro, vol. 72, art. 105101, pp. 1-8, 2021. doi : 10.1016/j.tiv.2021.105101.ArsenicCadmiumCombinationHeavy metalsHepatotoxicityMercuryPostprint Article