Figure 1.

(A) MTT assay was performed to determine the IC₅₀ value and cell viability after 24 h treatment with metformin (Met), at increasing concentrations (from 0.5 mM to 10 mM). Cell viability is the quantification of live cells and is expressed as the relative percentage to untreated controls. IC₅₀ value (that is, the concentration of Met which exhibited 50% cell viability in SEM-1 cells) was 5 mM. Histograms are representative of a minimum of three replicates. Cell viability data are shown as mean + s.e.m. (B) Growth curves of SEM-1 cells, either untreated (black squares) or exposed to Met 1 mM (gray squares) and 5 mM (white squares) for up to 48 h, as obtained by the Trypan Blue dye exclusion counting method. *p < 0.05 vs untreated cells. (C) Representative pictures of SEM-1 cells in adherent culture conditions: a) untreated; b) exposed to Met 5 mM for 24 h. Scale bar: 200 µm.