Figure 8

CXCR7 is required for CSC activity in vitro. (A) The neurosphere formation assay using CXCR7^bright and CXCR7^dim sorted cells from GBM xenografts T3832, T387 and T4121. CXCR7^bright cells exhibited a greater ability to form spheres than did CXCR7^dim cells. (B) Neurosphere formation assay using sorted CD133⁺ CSCs from GBM xenograft T4121. CXCR7 inhibitor CCX771, but not its inactive chemical analogue CCX704, inhibited sphere formation. Inhibition of sphere formation was greater with 1 μ M CCX771 than with 100 nM CX771 or with 1 μg ml⁻¹ (1.3 μ M) AMD3100. Similar results were observed with GBM xenograft T3832 (not shown).