Sulfasalazine reduces bile acid induced apoptosis in human hepatoma cells and perfused rat livers.

Background: Bile acid-induced apoptosis in hepatocytes can be
antagonized by NF-κBdependent survival pathways. Sulfasalazine
modulates NF-κB in different cell types. We aimed to determine the
effects of sulfasalazine and its metabolites sulfapyridine and
5-aminosalicylic acid (5-ASA) on bile acid-induced apoptosis in
hepatocytes. Methods: Apoptosis was determined by caspase assays
and immunoblotting, NF-κB activation by EMSA and reporter gene
assays, generation of reactive oxygen species (ROS)
fluorometrically, bile secretion gravimetrically and bile acid
uptake radiochemically and by gaschromatography in HepG2-Ntcp cells
and isolated perfused rat livers. Results: Glycochenodeoxycholic
acid (GCDCA, 75μmol/L)-induced apoptosis was reduced by
sulfasalazine dose-dependently (1-1000 μmol/L) in HepG2-Ntcp cells,
whereas its metabolites 5- ASA and sulfapyridine had no effect.
Sulfasalazine significantly reduced GCDCA-induced activation of
caspases 9 and 3. In addition, sulfasalazine activated NF-κB, and
decreased GCDCA-induced generation of ROS. Bile acid uptake was
competetively inhibited by sulfasalazine. In perfused rat livers,
GCDCA (25 μmol/L)-induced liver injury and extensive hepatocyte
apoptosis were significantly reduced by simultaneous administration
of 100 μmol/L sulfasalazine: LDH and GPT activities were reduced by
82% and 87%, respectively, and apoptotic hepatocytes were observed
only occasionally. GCDCA uptake was reduced by 45±5% when
sulfasalazine was coadministered. However, when 50% of GCDCA (12.5
μmol/L) were administered alone, marked hepatocyte apoptosis and
liver injury were again observed questioning the impact of reduced
GCDCA uptake for the antiapoptotic effect of sulfasalazine.
Conclusion: Sulfasalazine is a potent inhibitor of GCDCA-induced
hepatocyte apoptosis in vitro and in the intact liver.