Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a potential chemotherapeutic agent for cancer, is not thought to be hepatotoxic. We have recently demonstrated, however, that bile acids increase TRAIL-R2/DR5 expression in a human liver cell line and render these cells susceptible to TRAIL-mediated apoptosis. These data suggest TRAIL may be hepatotoxic in cholestasis. The aim of this study was to directly assess TRAIL hepatotoxicity in bile duct-ligated mice, a model of extrahepatic cholestasis. Bile duct-ligated mice (3 days) were used for these studies. TRAIL-R2/DR5 expression was assessed by real-time and immunoblot analysis. The TRAIL death-inducing signaling complex (DISC) was evaluated by immunoprecipitation and immunoblot techniques. Bile duct ligation increased both liver TRAIL-R2/DR5 mRNA and protein expression (>10-fold). Following TRAIL administration (60 μg/mouse, i.v.) to bile duct ligation (BDL) mice, terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive hepatocytes, liver tissue caspase 3-like activity, and serum alanine aminotransferase values increased significantly compared with vehicle-treated BDL mice. The effect of TRAIL on the liver was direct, as the TRAIL DISC (Fas-associated death domain and procaspase 8 protein) was detected in liver tissue. TRAIL-mediated hepatocyte apoptosis in bile duct-ligated mice was associated with significant hepatotoxicity, as assessed by histopathology, although there was no animal mortality. In conclusion, these data define conditions under which TRAIL is hepatotoxic.
Footnotes
-
This work was supported by grants from the National Institutes of Health (DK41876), the Palumbo Foundation, Pittsburgh, Penn and by the Mayo Foundation (Rochester, MN).
-
DOI: 10.1124/jpet.102.040030
- Abbreviations:
- TRAIL
- tumor necrosis factor-related apoptosis-inducing ligand
- TNF
- tumor necrosis factor
- FADD
- Fas-associated death domain
- DISC
- death-inducing signaling complex
- BDL
- bile duct ligation
- PAGE
- polyacrylamide gel electrophoresis
- ALT
- alanine aminotransferase
- TUNEL
- terminal deoxynucleotidyl transferase dUTP nick-end labeling
- PCR
- polymerase chain reaction
- PMSF
- phenylmethylsulfonyl fluoride
- CHAPS
- 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid
- DR
- death receptor
- Received June 4, 2002.
- Accepted July 2, 2002.
- The American Society for Pharmacology and Experimental Therapeutics
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|