Figure 1. Characterization of MDA-MB-231 and MDA-MB-453 cancer stem cell–like (CSC-like) and non-stem cancer (non-CSC) cells.
(A) Cells were transfected with a plasmid encoding GFP under the Oct-3/4 promoter for selection of stem-like cells or RFP encoding under the control of the CMV promoter for selection of non-stem cells. After selection using G418, positive colonies were verified by tumor markers (CD44, CD24, and Oct-4) expression and then pooled. Phase-contrast images or fluorescence images of Oct-3/4-GFP-transfected stem-like cells (left panels) and CMV-RFP-transfected non-stem cells (right panels) were visualized by light (phase-contrast) or UV (fluorescence) microscopy, respectively. (B) Stem-associated Oct-4 gene expression was examined in stem-like cells (left side) and non-stem cells (right side) by western blot analysis. Actin was shown as an internal standard. (C) Flow cytometry characterization of CSC-like or non-stem cells was performed by staining with surface marker antibodies (CD24, CD44) and evaluated by flow cytometry.