Fig. 4.

Insulin enhances β-catenin levels in human lung epithelial cells. The key molecular intermediates of PI3K/Akt signaling have been assessed for their role in insulin-induced increase in β-catenin levels. Human transformed bronchial epithelial (BEAS2B) cells were treated with insulin (1 μg/ml) with/without wortmannin [Wort (1 μM)] pretreatment in vitro. After 24 h the total cell protein was analyzed, by immunoblotting, for activated insulin receptor 1β (IR1β) (A), phosphorylated Akt (pAkt; B), phosphorylated GSK3β (p-GSK3β; C), and β-catenin (D). Data represent means ± SE, n = 6, *P ≤ 0.05; **P < 0.01 (significant insulin effect); ***P < 0.001 (significant wortmannin effect), compared with wortmannin alone or untreated control. GAPDH, glyceraldehyde-3-phosphate dehydrogenase.