Objective: To investigate the inhibitory effect of salinomycin on human breast cancer cells in vitro, and to explore the related molecular mechanism.
Methods: Human breast cancer MDA-MB-231 cells were treated with salinomycin at different concentrations and at various time points. The effect of salinomycin on MDA-MB-231 cells proliferation was studied by CCK-8 method. The cell cycle status was examined by flow cytometry. RT-PCR and Western blot were used to detect the expression of Shh, Smo and Gli1 in the Hedgehog pathway at mRNA and protein levels.
Results: Proliferation of MDA-MB-231 cells treated with salinomycin was markedly inhibited in a concentration and time dependent manner. Salinomycin at concentrations of 0, 0.4, 0.8 and 1.6 µmol/L inhibited the growth at the rates of 11.18%, 25.88%, 50.03%, 92.65%, respectively. Salinomycin prevented MDA-MB-231 cells from G1 into S phase. Salinomycin at concentrations of 0, 0.8 and 1.6 µmol/L resulted in S-phase percentage of 25.03%, 11.85% and 35.21%, respectively (P < 0.05). RT-PCR and Western blot showed that the expression of key elements Shh, Smo and Gli1 in the Hedgehog pathway was inhibited by salinomycin in a concentration dependent manner (P < 0.05).
Conclusion: Salinomycin prevents breast cancer cell transition from G1 to S phase through downregulation of the target genes of Hedgehog signaling pathway, leading to an effective inhibition of MDA-MB-231 cells.