Fig. 2

The analogs 2a–c are more efficient than salinomycin against CSCs at a 50 nM concentration. a The CD44⁺/CD24⁻ population evaluated using flow cytometry after 72 h of treatment. b The ALDH⁺ population evaluated using flow cytometry after 72 h of treatment. c Colony forming efficiency evaluated using a serum free soft agar assay. The cells were treated for 72 h and then reseeded at cloning density. The colonies were counted after 2 weeks of incubation. d Colonies obtained from the serum free soft agar assay. Bars = 40 μm. Data are represented as mean ± SEM for n = 4. *P < 0.05, **P < 0.01, ***P < 0.001. ns: no significant difference. SA: salinomycin, 2a: carbamate, 2b: acetate, 2c: carbonate and 3: C1-methyl ester