Table 1.
Qualitative effect of growth factors on UB cell tubulogenesis
| Growth factor | Process formation (24–48 hr) | Cord-like structure (5–6 days) | Tubules with lumen (>10 days) |
|---|---|---|---|
| HGF | + | ± | − |
| EGF | + | − | − |
| TGF-α | + | − | − |
| bFGF | + | ± | − |
| IGF-1 | + | + | − |
| PDGF | − | ND | ND |
| GDNF | − | − | − |
| TGF-β1 | − | ND | ND |
| BSN-CM | + | + | + |
| GF-mix | + | + | − |
Growth factors were applied on top of UB cell collagen gel suspension culture. Percentage of cells/colonies exhibiting tubules/processes was evaluated for each condition and compared to control condition (BSA or 1% FCS). If the specific growth factor treatment significantly increased tubulogenesis (i.e., P < 0.05 vs. control by unpaired Student’s t test), the growth factor was marked +. If not, the growth factor was marked −. ± indicates variable result among experiments. ND, not done. Process and formation data were derived from five separate experiments, cord-like structure data were derived from three separate experiments. Tubules with lumen data were derived from two separate experiments. Only BSN-CM induced tubules with lumens. GF-mix contains HGF, EGF, bFGF, IGF-1, and GDNF.