CD133-related phenotype of MDA-MB-231 cells. (A) CD133low and CD133high cells, obtained from MDA-MB-231 cells by positive magnetic separation with CD133/1 Micro Beads, were subjected to the cytofluorimetrical evaluation of CD133 expression with PE-conjugated 293C3 antibody, according to the manufacturer instructions. The data are presented on a biparametric dot plot, in which the mean fluorescence intensity (MFI) of the entire population is indicated. (B) Intracellular CD133 amount in CD133low and CD133high cells measured with PE-conjugated 293C3 antibody. The MFI of the entire populations were presented as column bar ± SD. The asterisk denotes statistical difference (P < 0.05). (C) CD133 surface expression measured by flow cytometry after staining with PE-conjugated 293C3 antibody of CD133low and CD133high cells cultured in the presence of 2.5 μg/ml Tunicamycin for 24 hours. The open histograms, outlined by coloured lines, represent positive staining for CD133 and gray filled histogram shows negative control stained with matched isotype antibody. (D) Adhesion area of CD133low and CD133high cells measured with the ImageJ software. The data are the mean of 3 separate experiments ± SD. The asterisk indicates statistically significant difference (P < 0.05). (E) Dynamic monitoring of proliferation, migration and invasiveness through Matrigel using xCELLigence system for the indicated times of CD133low and CD133high cells. Error bars indicate ± SD. The data are representative of three separate experiments.