Cell–cell contacts prevent t-BuOOH-triggered ferroptosis and cellular damage in vitro by regulation of intracellular calcium

Abstract

Tert -butyl hydroperoxide ( t -BuOOH) is an organic hydroperoxide widely used as a model compound to induce oxidative stress. It leads to a plethora of cellular damage, including lipid peroxidation, DNA double-strand breaks (DNA DSBs), and breakdown of the mitochondrial membrane potential (MMP). We could show in several cell lines that t -BuOOH induces ferroptosis, triggered by iron-dependent lipid peroxidation. We have further revealed that not only t -BuOOH-mediated ferroptosis, but also DNA DSBs and loss of MMP are prevented by cell–cell contacts. The underlying mechanisms are not known. Here, we show in murine fibroblasts and a human colon carcinoma cell line that t -BuOOH (50 or 100 µM, resp.) causes an increase in intracellular Ca 2+ , and that this increase is key to lipid peroxidation and ferroptosis, DNA DSB formation and dissipation of the MMP. We further demonstrate that cell–cell contacts prevent t -BuOOH-mediated raise in intracellular Ca 2+ . Hence, we provide novel insights into the mechanism of t -BuOOH-triggered cellular damage including ferroptosis and propose a model in which cell–cell contacts control intracellular Ca 2+ levels to prevent lipid peroxidation, DNA DSB-formation and loss of MMP. Since Ca 2+ is a central player of toxicity in response to oxidative stress and is involved in various cell death pathways, our observations suggest a broad protective function of cell–cell contacts against a variety of exogenous toxicants.

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