Figure 4. Effect of salinomycin and paclitaxel treatment on breast CSC numbers.

(a) HMLER cells were treated with DMSO, paclitaxel or salinomycin at the specified doses for 4 days, and then allowed for recover in the absence of treatment for 4 days. Percent of CD44^high/CD24^low cells after compound treatment in independent experiments with two different HMLER cell populations (HMLER_1, HMLER_2). The CD44/CD24 FACS profiles are shown for a subset of HMLER_2 compound treatments with the green ellipse () denoting the CSC-enriched fraction and the blue ellipse () the CSC-depleted fraction. (b) Quantification of tumorsphere-formation with HMLER cells treated as in (a). (c) Heterogeneous populations (control/EMT mixtures) of HMLE and HMLER cells (HMLE_Mx, HMLER_Mx, respectively) were compound-treated for 4 days, cultured in the absence of compound for 4 days, and the percent of CD44^high/CD24^low cells quantified by FACS. (d) Quantification of mammosphere-formation in HMLE_Mx and HMLER_Mx populations compound-treated as in (a). Phase-contrast images of mammospheres are shown. (e) In vitro growth curves of HMLER cells compound-treated as in (a) are shown. (f) Compound-pretreated MCF7Ras (4000 cells/well) and 4T1 cells (1000 cells/well) were seeded in the absence of compound and tumorsphere formation assessed at 10 days. (g) The fraction of viable cells after compound treatment was assessed using trypan-blue exclusion for both the parental 4T1 line and a paclitaxel-resistant 4T1 line (4T1-TaxR).