β-catenin expression remains constant during RA-induced epithelial differentiation.

<p>(A–B) H9 cells were treated without (A) or with (B) 1 µM RA in UM for 4 days. Representative phase contrast images are shown. Scale bar = 100 µm. (C–D) Quantitative polymerase chain reaction (PCR) of cDNA harvested from H9 cells cultured in UM with or without RA for 4 days. (C): Oct4 expression was significantly reduced upon RA addition; *p<0.05, UM versus RA. (D): β-catenin mRNA expression remained constant upon RA addition, p>0.05, UM versus RA. Error bars represent SEM of three biological replicates. (E) Western blot of protein extracts from H9 hESCs cultured for 4 days in UM without (−) or with (+) RA and CM.