Fig. 2

Low concentrations of metformin selectively decreased the CD44⁺CD117⁺ ovarian cancer cell population. SKOV3 (a, b, c) and A2780 (d, e, f) cells were incubated with different concentrations of metformin for 72 hours, and the proportions of cells expressing different CSC surface markers were determined by flow cytometry. For both cell lines, the proportions of CD133⁺ and ALDH⁺ were not altered by treatment with low concentrations of metformin (0.03–0.3 mM) (b, c, e, f), but the proportion of CD44⁺CD117⁺cells was reduced in a dose-dependent manner (a, d). ALDH aldehyde dehydrogenase. * Significant difference compared with control (P < 0.05)