IRON MODULATION OF LPS-INDUCED MANGANESE SUPEROXIDE-DISMUTASE GENE-EXPRESSION IN RAT-TISSUES

Mitochondrial superoxide dismutase (MnSOD) is usually diminished in ca ncer cells, We observed that in vivo treatment with LPS produces a str ong increase of MnSOD mRNA levels and a weak induction of an inactive protein in rat hepatocarcinomas. In normal liver iron deficiency, obta ined with desferrioxamine administration, produces a decrease in the M nSOD induction by LPS, indicating that such induction could depend on tissue iron content, However, no change in MnSOD mRNA has been observe d in iron-overloaded tumor tissue, Thus, iron is possibly involved in the transcriptional regulation of the protein, in combination with som e other unknown factor that appears to be deficient in tumor cells. (C ) 1997 Federation of European Biochemical Societies.