Figure 4.

Long-term maintenance of CSC clonogenic potential. (A) Schematic representation of long-term culture of sphere-derived tumor cells under adhesion conditions. Tumor spheres from holospheres, merospheres, or paraspheres were isolated and seeded into culture in monolayer. Tumor cells from each group were maintained in monolayer culture for up to 10 passages; (B) Schematic representation of tumor cells derived from groups 1, 2, and 3 isolated from passages 2 and 10 and seeded into ultra-low adhesion culture dishes; (C) Tumor cells from group 1 (initially derived from holospheres) regenerate holospheres, merospheres, and paraspheres by passages 2 and 10; (D) Tumor cells from group 2 (initially derived from merospheres) only generated holospheres by passage 2 but failed to generate holospheres by passage 10; (E) Tumor cells from group 3 (initially derived from paraspheres) do not regenerate holospheres.