FGF19 activates PI3K/Akt/HIF-1α signaling pathway and upregulates HOXB5 expression. (A) Relative mRNA and protein level of HOXB5 were measured by RT-qPCR and Western blotting. (B) HOXB5 promoter luciferase activity was measured after FGF19 stimulation in PLC/PRF/5 cells. (C) Luciferase activity was detected after the transfection of truncated and mutated HOXB5 promoter constructs and FGF19 treatment. (D-F) After transfection of HIF1α shRNA or control shRNA, PLC/PRF/5 cells were then treatment with FGF19. HOXB5 promoter activity (D) and HOXB5 mRNA expression RT-qPCR (E) and protein expression (F) were shown. (G) After pretreatment of signaling pathway inhibitors of PI3K, ERK, JNK, P38, PKC, mTOR and STAT3, PLC/PRF/5 cells were stimulated with FGF19. The expression of HOXB5, pFGFR4 and total or phosphorylated levels of AKT, ERK, JNK, P38, PKC, P70S6K and STAT3 were shown by western blotting. (H) A ChIP assay shown the relative enrichment of HIFIα on HOXB5 promoter when the PLC/PRE/5 cells were stimulated with FGF19 and signaling pathway inhibitors.