Fig 2.

Collagen-adherent cells are enriched in putative TICs. A: Mean percentage of cells with α2β1^hi/CD44^hi phenotype in PCa cell lines. B: Time-of-adherence assay performed on multiple PCa cell lines displaying the 5-min adherent cell fraction as a percentage of total cells. Data represent three independent experiments performed in triplicates. C: Flow cytometric analyses of DU145 and PC3 cells after collagen adherence showing both increased expression of CD44 and CD133 in the 5-min (5′) adherent cells compared to the 20 minutes (20′) non-adherent cells, and higher mean fluorescence intensity (MFI) of 5 minutes collagen-I-adherent (α2β1^hi/CD44^hi) cells (Adherent) compared to 20 min-non-adherent (α2β1^low/CD44^low) cells (Non-adherent), and IgG control (IgG). D: CD133 expression in various subsets of DU145 and PC3 cells. In a representative experiment, α2β1^hi/CD44^hi (pink) showed 0.1% and 0.01% of the cells positive for CD133 from DU145 and PC3 cells respectively, and spheroids from these α2β1^hi/CD44^hi cells (green) showed upregulated CD133 levels up to 5.22% in DU145 cells and 0.083% in PC3 cells (P< 0.001 for both cell lines in three independent experiments). E: Primary prostate cancer cells have increased expression of CD44 and CD133 in the 5-min adherent cells compared to the 20 min-non-adherent cells. Mean percentages from analyses of six cases are displayed. Higher expression of α2β1/CD44 and upregulation of CD133 when cells are grown as spheres were detected in the 5-min adherent cells compared to the 20 minutes non-adherent cells, and were seen with all six patient samples examined.