Figure 9.

Repression of Bard1 abrogates hydrocortisone-induced lumen formation by TAC-2 cells. Cells were suspended in collagen gels at 10⁴ cells/ml and incubated with 1 μg/ml hydrocortisone and 10 μg/ml insulin for 8 d. Under these conditions, PC3 cells form alveolar-like cystic structures containing widely patent lumina (A) delimited by a palisade of cubic epithelial cells (D). In marked contrast, AB-I cells form solid ball-like structures (B) devoid of lumen (E), and AB-K cells form irregular aggregates (C) containing small focal lumina (F). The three-dimensional structures illustrated in A, B, and C are representative of the vast majority of colonies formed by PC3, Ab-I, and AB-K cells, respectively. A–C, Bright-field microscopy; D–F, semithin sections. Bars, 100 μm.