Figure 5. Tumor forming ability of CD133⁺ subfractions.

A) Validation of CD133⁺ cell fractions obtained by column isolation. Purity of injected cell fractions is shown. Cells used for transplantation were sorted by FACS and non-viable cells were excluded using SYTOX Green. Tumor-forming cells are highly enriched in the CD133⁺ cell fraction. Shown are studies with CD133⁺ vs CD133⁻ cells from eight pooled ovc316-X xenografts. (N = 10 animals per group). Tumor formation was evaluated 4 months after inoculation. TIC CD133⁺: 1/191, TIC CD133⁻: 1/16725. Chi-square = 8.25, p<0.01. B) Column-isolated CD133⁺ cells were further subdivided into Tie2⁺ and Tie2⁻ fractions by FACS. Cells used for transplantation were sorted by FACS and non-viable cells were excluded using SYTOX Green. Tumor-forming abilities are more pronounced in CD133⁺/Tie2⁻ cells. Shown are data from transplantation of CD133⁺/Tie2⁺ vs CD133⁺/Tie⁻ cells from ovc316-XC (N = 10). TIC CD133⁺/Tie2⁺: 1/10593, TIC CD133⁺/Tie2⁻: 1/650. Chi-square: 6.74, p<0.01. C) Immunofluorescence analysis of tumors that developed after transplantation of CD133⁺/Tie⁻ cells. D and E) Analysis of fractions derived from patient biopsies. D) Schematic of cell isolation. E) Tumor formation after transplantation of CD133⁺/Tie2⁻ and CD133⁺/Tie2⁺ cells derived from ovc100506-biopsy. Tumor formation was evaluated 3 months after inoculation. TIC CD133⁺/Tie2⁻: 1185, TIC CD133⁺/Tie2⁺: n.a.