Abstract (eng)
Zinc is an essential component of nutrition and fulfils various biological functions on the protein and DNA-level. Besides it acts as a signal molecule and mediates signals from the extracellular space to the nucleus via enzyme cascades.
The analyses shown here give information about its role as activator of the Mitogen Activated Protein Kinase (MAPK) pathway, which regulates cell processes.
In the context of this work CaCo2 cells, representatives of a cancerous colon cell line, were applied in order to show that the amount of extracellular zinc and the period of incubation have an effect on cell viability. Zinc concentrations in the range of 100μM ZnCl2 at long-time incubations do not have toxic effects on the cells, while high zinc concentrations produce effects that induce changes in cell morphology and initiate the apoptotic and/or necrotic cell death.
The analyses were conducted using CaCo2 cells in two differentiation states. Results showed that differentiated cells have a higher zinc tolerance than undifferentiated cells. The effects of zinc on cellular events were demonstrated by the Western Blot method, in particular by the stimulation level of the signal kinases pERK1, pERK2 and p-p38.
Experiments with Crystal violet showed a dissociation of single cells from the monolayer and a decreased adhesion with increasing zinc concentrations.
The analyses demonstrate the activation of the MAPK pathway through zinc. These findings have a physiologic relevance, since zinc in low doses is essential for diverse bodily functions, however, excessive concentrations of zinc contribute to the floridity of various diseases.