Figure 3.

UB cells exhibit multicellular cords, tubules with lumens, and multicellular cysts in ECM gels in BSN-CM, depending on matrix composition. UB cells were suspended in 80% collagen type I/20% growth factor reduced Matrigel in the presence of BSN-CM containing 1% FCS. (A) After 7 days of culture, the cells grew to form multicellular cord-like structures. (B) After 15 days of culture, clear lumens could be seen in UB tubules. (C) When UB cells were suspended in 100% growth factor reduced Matrigel, even in the presence of BSN-CM and 1% FCS, they remained multicellular cysts even after 15 days of culture. (Bar = 50 μm.)