Mixing experiments with BUL cells show selection for CD133(+) melanoma. (a) From left: DsRed-expressing BUL CD133(+) cells, GFP-expressing CD133(-) BUL cells, and a 1:10 reconstituted mixture of the two visualized by GFP/DsRed merged fluorescence, and phase contrast microscopy. (b) Dose response of 1:10 reconstituted mixture DsRed-CD133(+) and GFP-CD133(-) subpopulations. The subpopulations were reconstituted in a 1:10 ratio, and mixed cells in triplicate wells were treated with different inhibitor concentrations; fates of each population were monitored by flow cytometry and ImageJ analysis of micrographs. (c) The surviving cells from the two subpopulations are expressed as a fraction of Red CD133(+)/Green CD133(-) at each drug dose. (d) IC50 for each treatment group. (e) MACS-sorted CD133(+) cells were tested for positivity over a 16-day period. (f) BAK cells were exposed to T, D, or T+D, and the levels of CD133 RNA determined by qRT-PCR.