Evaluation of cellular influences caused by calcium carbonate nanoparticles

•Cellular influences caused by three kinds of CaCO3 nanoparticles were evaluated.•One of the types of CaCO3 nanoparticles was highly soluble.•Soluble CaCO3 nanoparticles also induced a cell morphological change.•CaCO3 nanoparticles increased intracellular the Ca2+ level and activated calpain.•Cellular influence of CaCO3 nanoparticles is caused by intracellular calcium release. The cellular effects of calcium carbonate (CaCO3) nanoparticles were evaluated. Three kinds of CaCO3 nanoparticles were employed in our examinations. One of the types of CaCO3 nanoparticles was highly soluble. And solubility of another type of CaCO3 nanoparticle was lower. A stable CaCO3 nanoparticle medium dispersion was prepared and applied to human lung carcinoma A549 cells and human keratinocyte HaCaT cells. Then, mitochondrial activity, cell membrane damage, colony formation ability, DNA injury, induction of oxidative stress, and apoptosis were evaluated. Although the influences of CaCO3 nanoparticles on mitochondrial activity and cell membrane damage were small, “soluble” CaCO3 nanoparticles exerted some cellular influences. Soluble CaCO3 nanoparticles also induced a cell morphological change. Colony formation was inhibited by CaCO3 nanoparticle exposure. In particular, soluble CaCO3 nanoparticles completely inhibited colony formation. The influence on intracellular the reactive oxygen species (ROS) level was small. Soluble CaCO3 nanoparticles caused an increase in C/EBP-homologous protein (CHOP) expression and the activation of caspase-3. Moreover, CaCO3 exposure increased intracellular the Ca2+ level and activated calpain. These results suggest that cellular the influences of CaCO3 nanoparticles are mainly caused by intracellular calcium release and subsequently disrupt the effect of calcium signaling. In conclusion, there is possibility that soluble CaCO3 nanoparticles induce cellular influences such as a cell morphological change. Cellular influence of CaCO3 nanoparticles is caused by intracellular calcium release. If inhaled CaCO3 nanoparticles have the potential to influence cellular events. However, the effect might be not severe because calcium is omnipresent element in cell.