Fig. (2) Inhibitory effect of NiCl2 on U2OS (A) and HaCat (B) cell proliferation. The cells were exposed to increasing NiCl2 concentrations for 24, 48 and 72h and CFSE positive cells were detected and quantified by flow cytometry as described in the Materials and Methods. The results were expressed and reported as the percentage of untreated growing cells (n = 5). * (p<0.05) indicates significant differences between cell culture treated with NiCl2 and untreated controls.