Inhibition of hepatocarcinogenesis by the deletion of the p50 subunit of NF-kappa B in mice administered the peroxisome proliferator Wy-14,643


Glauert H., Eyigor A., Tharappel J., Cooper S., Lee E., Spear B.

TOXICOLOGICAL SCIENCES, vol.90, no.2, pp.331-336, 2006 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 90 Issue: 2
  • Publication Date: 2006
  • Doi Number: 10.1093/toxsci/kfj116
  • Title of Journal : TOXICOLOGICAL SCIENCES
  • Page Numbers: pp.331-336

Abstract

Wy-14,643 (WY) is a hypolipidemic drug that induces hepatic peroxisome proliferation and tumors in rodents. We previously showed that peroxisome proliferators increase NF-kappa B DNA binding activity in rats, mice, and hepatoma cell lines, and that mice deficient in the p50 subunit of NF-kappa B had much lower cell proliferation in response to the peroxisome proliferator ciprofibrate. In this study we examined the promotion of hepatocarcinogenesis by WY in the p50 knockout (-/-) mice. The p50 -/- and wild type mice were first administered diethylnitrosamine (DEN) as an initiating agent. Mice were then fed a control diet or a diet containing 0.05% WY for 38 weeks. Wild-type mice receiving DEN only developed a low incidence of tumors, and the majority of wild-type mice receiving both DEN and WY developed tumors. However, no tumors were seen in any of the p50 -/- mice. Cell proliferation and apoptosis were measured in hepatocytes by BrdU labeling and the TUNEL assay, respectively. Treatment with DEN + WY increased both cell proliferation and apoptosis in both the wild-type and p50 -/- mice; DEN treatment alone has no effect. In the DEN/WY-treated mice, cell proliferation and apoptosis were slightly lower in the p50 -/- mice than in the wild-type mice. These data demonstrate that NF-kappa B is involved in the promotion of hepatic tumors by the peroxisome proliferator WY; however, the difference in tumor incidence could not be attributed to alterations in either cell proliferation or apoptosis.