Figure 7. Inhibition of gankyrin by FXR prevents liver cancer in Little mice.

A. Expression of proteins of FXR-gankyrin-pathway. Western blotting was performed with nuclear extracts using antibodies shown on the right. β-actin control is shown for the C/EBPα/Rb/p53 membrane. Bottom image. Gankyrin was immunoprecipitated and the IPs were probed with Abs to C/EBPα, p53, Rb and HNF4α. B. Upper image. Levels of FRX, gankyrin and PCNA were normalized to β-actin and calculated as a fold elevation compared to control WT animals. Bottom image shows levels of C/EBPα, p53 and Rb calculated as percentage of the levels observed in WT untreated mice. C. Levels of mRNA determined by qRT-PCR. D. Expression of C/EBPβ and HDAC1 proteins and amounts of C/EBPβ-HDAC1 complex are increased in Little mice. Western blotting shows levels of C/EBPβ and HDAC1. C/EBPβ-IP: C/EBPβ was immunoprecipitated from nuclear extracts and these IPs were probed with Abs to HDAC1 and to C/EBPβ. Bar graphs show amounts of C/EBPβ-HDAC1 complexes in WT and Little DEN treated mice as ratios to amounts in WT un-treated livers. E. ChIP assay with gankyrin promoter in livers of WT DEN-treated mice and in Little DEN-treated mice. F. Hypothetical pathway by which liver cancer activates gankyrin and causes gankyrin-mediated degradation of tumor suppressor proteins.