Chase ABC induced morphological changes of NPC spheres. (A) A phase-contrast photomicrograph shows floating neurospheres derived from disassociated NPCs cultured for 24 hours in growth medium supplemented with EGF and bFGF;. (B-D) Exposure of neurospheres to Chase ABC for 24 hours (B, C) and 48 hours (D) induced the neurospheres to attach to the bottom of the wells and migration of cells outward to form irregular cell clusters. Boxed area in (B) is viewed in (C) at higher magnification, which showed that many NPCs migrated out of the spheres and emerged irregular small processes from the cell body. Scale bar: A and C, 100 μm; B and D, 200 μm.