Fig. 1

Metformin inhibits proliferation of castration-resistant C4–2, 22Rv1 and PC-3 prostate cancer cells. A Each cell line was treated with either PBS vehicle or different concentrations of metformin (0.2–20 mM) for 4 days. Following treatment, the cells were detached from the tissue culture plate and counted using a Coulter counter. Each bar represents the mean ± SD for three wells. *, P > 0.05 compared to PBS vehicle (0 mM metformin). B Cells were first treated with PBS vehicle or metformin (1–10 mM) for 4 days. The PrestoBlue assay was then performed to measure the viability of treated cells. Each bar represents the mean ± SD for four wells. *, P > 0.05 compared to phosphate buffered saline (PBS) vehicle (0 mM metformin)