Figure 3. Apical-basal polarity and lumen formation of epithelial spheroids in Matrigel.

Spheroids of epithelial cells after culturing for 2 days (EpH4 cells) or 3 days (MDCK II and R2/7 α-Cate cells) in Matrigel. They were stained for DNA (yellow), ZO-1 (blue), Scrib (red), and PKC zeta (green). Series of confocal optical sections were obtained and projected on a single plane. In MDCK II cells, single lumens lined with PKC zeta (yellow arrowhead) and enclosed by a ZO-1 network (yellow arrow) were observed. EpH4 cells typically had no lumen and ZO-1 was distributed on the surface of the spheroid (yellow arrow). R2/7 α-Cate cells had several small lumens inside the spheroid (yellow arrows and arrowheads). Bar, 10 µm.