Figure 6.

Differentiation-related protein expression in conventional culture and epithelial histogenesis in organotypic culture by urothelial and tracheobronchial epithelial cells. (A): Western blot analysis. Urothelial cells and tracheobronchial epithelial cells were compared with epidermal keratinocytes and hES-derived, keratinocyte-like (hESderK) cells for p63, K5, and involucrin expression during growth in the feeder/FAD culture system (except for lane 2). Lanes: (1) strain N; (2) strain N grown in keratinocyte serum-free medium medium; (3) N/bmi1; (4) HBl-10U; (5) HBl-10U/bmi1/TERT; (6) TrBEp-1/bmi1/TERT; (7) hESderK/bmi1. Note that p63 and K5 expression levels were highest for epidermal keratinocytes and were positive, but lower, for the other cell types examined. Involucrin was expressed by all cell lines, but was highest in normal epidermal keratinocytes and urothelial cells and at lower levels by bmi1 transductants of these cell types. The absence of stratification in hESderK cells cultured on plastic culture dishes likely contributed to the very low levels of this suprabasal differentiation-specific protein in hESderK/bmi1 cultures. (B): Suprabasal differentiation protein expression in organotypic cultures of urothelial and tracheobronchial epithelial cells. Top row: HBl-10U/bmi1/TERT. Bottom row: TrBEp-1. Panels show typical fields. Average total epithelial thickness in μm, number of cell layers, and number of stratum corneum cell layers were as follows for HBl-10U/bmi1/TERT (90μ, 6,1) and TrBEp-1 (70μ, 6, 2). Note suprabasal expression of involucrin and K10 in suprabasal cells of both cell types. Bar in top left panel is 100 μm long. Abbreviations: TERT, telomerase catalytic subunit.