Combination treatments with salinomycin and chemotherapy drugs synergistically target cancer stem cells. The mean combination index (CI) value of combination treatments in JLO-1 were calculated as explained in the Methods. CI < 1 indicates synergy, CI = 1 (denoted by dashed line) indicates additivity, and CI > 1 indicates antagonism. (A) CI graph depicts cytotoxic interactions between 4 μM salinomycin and increasing doses of cisplatin (1, 2, 5, 10, 20 μM) in JLO-1. (B) CI graph depicts cytotoxic interactions between 0.5 μM salinomycin and increasing doses of taxol (1, 2, 3, 4, 6, 8 nM) in JLO-1. (C) CI graph depicts cytotoxic interactions between 0.5 μM salinomycin and increasing doses of taxol (1, 2, 3, 4, 6, 8 nM) in a parallel experiment for UMSCC-10B. (D) Trypan blue dye exclusion assay further verifies observed synergy for JLO-1 receiving combination treatments of 0.5 μM salinomycin + 3nM taxol or 4 μM salinomycin + 5 μM cisplatin. Calculated CI values are shown above respective bars. All error bars represent standard deviation.
Kuo et al. BMC Cancer 2012 12:556 doi:10.1186/1471-2407-12-556