27 While ICG-001 expectedly decreased TOPflash reporter activity, it unexpectedly reduced p65 reporter activity, which may be due to an increase in non-CBP-bound pool of β-catenin (Fig. 7D). These findings suggest that β-catenin modulation of NF-κB signaling is regulatable through manipulation of β-catenin expression; however, only agents that suppress total β-catenin levels may be useful to induce p65 activation. We

next examined conditions in which β-catenin was overexpressed both in vitro and in vivo to determine the effect on p65 expression and activity. Hep3B cells were transfected with control plasmid or plasmid expressing constitutively active S33Y/β-catenin or S45Y/β-catenin, simultaneous with p65 or TOPflash selleckchem reporters. While expression of mutated β-catenin induced TOPflash activity, it also resulted in significantly repressing learn more p65 activity (Fig. 7E). We next treated Hep3B cells with an escalating dose of lithium chloride (LiCl), a known inhibitor of GSK-3β that in turn induces β-catenin protein stabilization. This led

to a dose-dependent increase in TOPflash reporter activity and a concomitant and significant decrease in p65 reporter activity (Fig. 7F). Finally, we analyzed human hepatocellular carcinoma (HCC) tissue array via IHC. Tumor-wide glutamine synthetase (GS) staining is a good indicator of β-catenin mutations.28, 29 Of 93 HCC tumors on Biomax HCC tissue array, 30 were GS-positive, consistent with the numbers of HCC with

β-catenin gene mutations (reviewed by Nejak-Bowen MCE公司 and Monga9). Of this subset, the majority of GS-positive HCC (63% [19/30]) were negative for p65 (Fig. 8A,B). These findings indicate that β-catenin activation in HCC negatively affects p65 expression and NF-κB activity. β-Catenin is a crucial component of the Wnt pathway, which plays multiple roles in liver homeostasis through its regulation of proliferation, differentiation, and regeneration. However, its role in hepatic injury remains unexplored. The analysis was initiated to test two common modes of hepatocyte apoptosis: Fas- and TNF-α-mediated cell death. We have reported that β-catenin and the HGF receptor c-Met associate at the cell surface.15 c-Met sequestration of the Fas receptor that can prevent Fas-mediated apoptosis in hepatocytes has also been reported.13 We also identified the Fas/β-catenin complex in the liver. Because HGF messenger RNA up-regulation (along with a dramatic reduction in Met protein levels) was evident in KO livers, we hypothesized that basal apoptosis may be due to destabilization of c-Met/Fas/β-catenin complexes, which may enhance free-Fas levels available for engagement with Fas ligands like Jo-2. However, the KO mice were as susceptible as WT mice to Fas-activation.