FIGURE 8.

ERK1/2 and p38 MAPK pathways in addition to TCF4/β-catenin signaling are necessary for HD5 expression in response to FGFR-3 signaling. A, β-catenin/TCF4-mediated transcriptional activation was assayed by luciferase activity in Caco2 cells transiently transfected with pTOPFlash and Renilla. B, HD5 mRNA levels were determined by quantitative real-time PCR. A and B, cells were treated for the last 24 h before harvest at 120 h post-transfection with PI3K (LY 294002), p38 MAPK (SB 203580), or ERK1/2 (UO126) inhibitors. FGF9 (50 ng/ml) was added daily beginning at 24 h post-transfection, and cells were harvested at 120 h post-transfection. Values are the mean ± S.D. (error bars) of n = 3. *, p ≤ 0.001.