Salinomycin Selectively Targets 'CD133+' Cell Subpopulations and Decreases Malignant Traits in Colorectal Cancer Lines

Cancer stem-like cells (CSCs) in colorectal cancers (CRC) may account for the failure of treatments because they are resistant to many current anticancer therapies. Salinomycin, a potassium ionophore, was recently identified as a selective inhibitor of breast CSCs. The human CRC cell lines HT29 and SW480 were treated with salinomycin and oxaliplatin. Cell viability was determined with cell counting kit 8. Fraction of CD133+ cell subpopulations was assessed by Flow Cytometric analysis. Clonogenecity and migration were determined with soft agar and Boyden chamber assays. Molecular changes were assessed by immunofluorescence staining, RT-PCR, and Western blot analysis. We report that salinomycin reduces the proportion of CD133+ subpopulations in human CRC HT29 and SW480 cells. Furthermore, salinomycin treatment decreases colony-forming ability and cell motility in HT29 cells. Moreover, salinomycin downregulates the expression of vimentin and induces the E-cadherin expression in HT29 cells. This study demonstrates the ability of salinomycin to selectively target "CD133+" cell subpopulations and decrease the malignant traits in colorectal cancer lines.