Fig 3.

Tumorigenic potential of collagen-adherent α2β1^hi/CD44^hi cells. A: The two fractions of α2β1^hi/CD44^hi cells and α2β1^low/CD44^low cells isolated after collagen adherence were assessed in colony forming efficiency assays. Images on the left demonstrate colonies derived from both fractions stained with crystal violet. Numbers of spheroid colonies, migrating, and invading cells are displayed as mean ± SD, and were done in triplicates. Self-renewal and in vitro tumorigenic potential of collagen-adherent α2β1^hi/CD44^hi DU145 cells are shown. Bars demonstrate the enhanced clonogenic ability of α2β1^hi/CD44^hi cells compared to α2β1^low/CD44^low cells. The two fractions of α2β1^hi/CD44^hi cells and α2β1^low/CD44^low DU145 cells isolated after collagen adherence were assessed for numbers of migrating cells. Data are displayed as mean ± SD, and were done in triplicates (*p<0.001). B: Both flanks of athymic nude (NCI^nu/nu) mice were injected with either total DU145 cells (ν), 5 min-adherent cells (λ), or 20 min-non-adherent cells (σ) (n=60 mice). Mean tumor growth rates are presented as mm³/day ± SD. C: The mean tumor volume was plotted as a function of time using the ellipsoid volume formula (length x width² x 1/2), assuming π = 3. P values shown are compared with total DU145 tumors. D–E: Self-renewal and in vitro tumorigenic potential of collagen-adherent α2β1^hi/CD44^hi PC3, LnCap and CWR22 PCa cells. D: Bars demonstrate the enhanced clonogenic ability of α2β1 ^hi/CD44^hi cells compared to α2β1^low/CD44^low PC3 and CWR22 cells. E: The two fractions of α2β1^hi/CD44^hi cells and α2β1^low/CD44^low PC3, LnCap and CWR22 cells isolated after collagen adherence were assessed for numbers of migrating cells. Data are displayed as mean ± SD, and were done in triplicates (*p<0.001).