Copper exposure modifies the content and distribution of trace metals in mammalian cultured cells.

With this work, we have determined the cellular content of Cu, Fe and Zn in different cell lines, by using total reflection X-ray fluorescence spectrometry (TXRF). In addition, we examined whether cellular exposure to 100 micromoles l(-1) of Cu-His modifies the intracellular content and distribution of these trace metals. Our results indicate that all the cell lines displayed the same pattern of relative intracellular abundance of trace metals (Cu<Fe<Zn). This pattern shifted to Fe<Zn<Cu, when extracellular copper concentration was increased. In HepG2 and Caco2 cells, copper exposure increased intracellular copper content while Fe and Zn decreased. Regarding cellular distribution of trace metals, they decreased in the cytosol fraction of HepG2 cells, after exposure to copper. Therefore, our results indicate that cellular adaptation to copper involves a new balance in the relative abundance of trace metals and induces changes in the cellular distribution of Cu, Zn and Fe.