Fig. 1

Tumor sphere cells possessed CSCs features. a Tumor spheres were isolated from 4 T1 cells, HCT116 cells, SW480cells, and HT29 cells by using cancer stem cell culture method as described in Experimental Procedures. Scale bars represent 100 μm. b The relative proportion of tumor sphere cells remained stable after 3 generations of replating. Results are shown as mean values ± SEM from three independent experiments. c The surface markers of 4 T1 parental cells and primary tumor sphere cells isolated from 4 T1 parental cells. Scale bars represent 50 μm. d The percentage of CD44 + CD24- cells in 4 T1 parental cells and tumor sphere cells. Results are from three independent experiments. e 4 T1 tumor sphere cells grown in 3D in matrigel formed acinar-like colony (a representative image under bright field, phase contrast microscopy) and differentiation markers (TP63, myoepithelial cell marker; EpCAM, epithelial cell marker). Data shown are representative of three independent experiments. f Tumors from tumor sphere cells containing glandular tubules stained with hematoxylin/eosin (H&E) and differentiation markers (TP63, myoepithelial cell marker; EpCAM, epithelial cell marker). Data shown are representative of three independent experiments. g Co-culture of tumor sphere cells (red fluorescence) and 4 T1 cells (green fluorescence) with drugs including cisplatin, methotrexate (MTX), doxorubicin (Dox), taxel, etoposide, or vincristine (VCR). After 2 days of incubation, much more tumor sphere cells survived than 4 T1 cells. Results are representative of three independent experiments. Scale bars =100 μm