Figure 1.

Metformin represses melanoma cell proliferation (a) Primary human melanocytes and melanoma cell lines A375, SKMel28, WM9 and G361 were treated with indicated concentrations of metformin. After 72 h, viable cells were counted using trypan blue dye exclusion method. (b) Human melanoma cells freshly isolated from tumor were stimulated for 72 h with indicated concentrations of metformin. Viability of the cells was estimated by trypan blue staining. (c) A375 and SKMel28 were treated with PBS and 10 mM metformin during different times, and cell viability was determined by trypan blue dye exclusion assay. For each experiment, cell number is expressed in percent of control (100%). Data are mean±S.D. of three independent experiments performed in triplicate. Significantly different from the corresponding control ^*P<0.05; ^**P<0.01; ^***P<0.001