Fig. 2.

Effect of melatonin treatment on the proliferation of human PCa cells and normal prostate epithelial cells. A) Effect of melatonin on cell growth in PCa cells: Following treatment of cells with melatonin (100μM-2mM; 48 hours), cell growth was assessed by Trypan Blue assay. Cell growth is expressed as percent growth (from total number of cells); B) Effect of melatonin on cell viability in PCa cells: Following treatment of cells with melatonin (100μM-2mM; 48 hours), viability was assessed by Trypan Blue assay. Cell viability is expressed as the percent viable cells out of the total number of cells. C) Effect of melatonin on colony formation ability of PCa cells: Cells were treated with melatonin (1mM or 2mM; 14 days) with fresh melatonin-supplemented medium being replaced every three days. After 14 days, colonies were fixed and stained with 0.5% crystal violet. The data presented are representative of three separate experiments with similar results. The data in Fig. 2 are expressed as mean ± SE of three experiments (p-value ≤ 0.01*).