CSC+ and CSC− tumor cells display similar proliferative capacity in the native state.

(A, B) CSC marker expressing primary sample were selected to undergo Ki-67 expression and apoptosis analysis. Data represent mean ± SEM; n = 10 for each type of leukemia, n = 8 for glioblastoma and for colon cancer, n = 9 for breast cancer and for melanoma. (A) Ki-67 expression of CSC+ and CSC− cells from human primary tumors. Single cell suspensions of human primary tumors were stained with antibodies specific to the CSC markers and Ki-67-FITC, followed by flow cytometric analysis. (B) Apoptosis assay of CSC+ and CSC− cells from human primary tumors. Single cell suspensions of human primary tumors were stained with antibodies specific to the CSC markers and Annexin V-FITC/7-ADD, followed by flow cytometric analysis. (C–D) Ki-67 expression (C) and apoptosis (D) assay of CSC+ and CSC− cells from human tumor cell lines cultured in serum-containing medium. Data represent mean ± SEM from 3 independent experiments. (E–F) Ki-67 expression (E) and apoptosis (F) assay of CSC+ and CSC− cells of xenografts derived from human tumor cell lines. Data represent mean ± SEM from 3 independent experiments. (G) DsRed-labeled CSC+ and EGFP-labeled CSC− cells originating from the same tumor cell lines were mixed according to their original ratios and co-cultured in serum-containing medium for 20 passages. Dots show the ratio of CSC+-derived to CSC−-derived (DsRed:EGFP) cells at different passages. Data represent mean ± SEM from 3 independent experiments.