Sulfasalazine reduces bile acid induced apoptosis in human hepatoma cells and perfused rat livers.
BACKGROUND
Bile acid induced apoptosis in hepatocytes can be antagonised by nuclear factor kappaB (NFkappaB) dependent survival pathways. Sulfasalazine modulates NFkappaB 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, NFkappaB activation by electrophoretic mobility shift assay and reporter gene assays, generation of reactive oxygen species (ROS) fluorometrically, bile secretion gravimetrically, and bile acid uptake radiochemically and by gas chromatography in HepG2-Ntcp cells and isolated perfused rat livers.


RESULTS
Glycochenodeoxycholic acid (GCDCA 75 micromol/l) induced apoptosis was reduced by sulfasalazine dose dependently (1-1000 micromol/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 NFkappaB and decreased GCDCA induced generation of ROS. Bile acid uptake was competitively inhibited by sulfasalazine. In perfused rat livers, GCDCA (25 micromol/l) induced liver injury and extensive hepatocyte apoptosis were significantly reduced by simultaneous administration of 100 micromol/l sulfasalazine: lactate dehydrogenase and glutamate-pyruvate transaminase 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 micromol/l) was administered alone, marked hepatocyte apoptosis and liver injury were again observed, questioning the impact of reduced GCDCA uptake for the antiapoptotic effect of sulfasalazine.


CONCLUSIONS
Sulfasalazine is a potent inhibitor of GCDCA induced hepatocyte apoptosis in vitro and in the intact liver.
Rust
C
C
Department of Medicine II-Grosshadern, University of Munich, Marchioninistrasse 15, 81377 Munich, Germany. christian.rust@med.uni-muenchen.de
Bauchmuller
K
K
Bernt
C
C
Vennegeerts
T
T
Fickert
P
P
Fuchsbichler
A
A
Beuers
U
U
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000378:metabolism / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D005455:Fluorescent Antibody Technique; D005999:Glycochenodeoxycholic Acid / Q000494:pharmacology*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D019804:Mesalamine / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D013427:Sulfapyridine / Q000494:pharmacology; D012460:Sulfasalazine / Q000378:metabolism / Q000494:pharmacology*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016328:NF-kappa B; D012460:Sulfasalazine; D019804:Mesalamine; D005999:Glycochenodeoxycholic Acid; C505407:CASP3 protein, human; C506433:CASP9 protein, human; C505410:Casp3 protein, rat; C506435:Casp9 protein, rat; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D013427:Sulfapyridine