Effects of mutant p53 expression on human 15-lipoxygenase-promoter activity and murine 12/15-lipoxygenase gene expression: evidence that 15-lipoxygenase is a mutator gene

Proc Natl Acad Sci U S A. 1999 Apr 13;96(8):4378-83. doi: 10.1073/pnas.96.8.4378.

Abstract

Human 15-lipoxygenase (h15-LO) is present on chromosome 17p13.3 in close proximity to the tumor-suppressor gene, p53. 15-LO is implicated in antiinflammation, membrane remodeling, and cancer development/metastasis. The murine BALB/c embryo fibroblast cell line, (10)1val, expresses p53 in mutant (mt) conformation when grown at 39 degrees C and in wild-type conformation when grown at 32 degrees C. Transfection of h15-LO promoter constructs (driving luciferase reporter) into (10)1val cells and into p53-deficient (10)1 cells resulted in a marked increase in h15-LO promoter activity in (10)1val cells at 39 degrees C, but not at 32 degrees C, or as compared with (10)1 cells. Transfection of h15-LO promoter deletion constructs, however, resulted in total loss of activity in both cell types at 32 degrees C and 39 degrees C. Cotransfection of (10)1 cells with h15-LO promoter (driving luciferase reporter) along with increasing levels of a mt p53 expression vector demonstrated dose-dependent capacity of mt p53 to induce 15-LO promoter activity. No effect was observed with wild-type p53. In contrast to h15-LO promoter activity, (10)1val cells had significantly lower levels of endogenous (murine) 12/15-LO (mouse analog of h15-LO) mRNA and protein when grown at 39 degrees C compared with cells grown at 32 degrees C. Our data support the hypothesis that loss of a tumor-suppressor gene (p53), or "gain-of-function activities" resulting from the expression of its mutant forms, regulates 15-LO promoter activity in man and in mouse, albeit in directionally opposite manners. The studies define a direct link between 15-LO activity and an established tumor-suppressor gene located in close chromosomal proximity.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Arachidonate 12-Lipoxygenase / genetics*
  • Arachidonate 15-Lipoxygenase / genetics*
  • Cells, Cultured
  • Embryo, Mammalian
  • Enhancer Elements, Genetic
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Gene Deletion
  • Genes, p53
  • Humans
  • Luciferases / genetics
  • Mice
  • Mice, Inbred BALB C
  • Promoter Regions, Genetic*
  • RNA, Messenger / genetics
  • Recombinant Fusion Proteins / biosynthesis
  • Transcription, Genetic
  • Transfection
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*

Substances

  • RNA, Messenger
  • Recombinant Fusion Proteins
  • Tumor Suppressor Protein p53
  • Arachidonate 12-Lipoxygenase
  • Arachidonate 15-Lipoxygenase
  • Luciferases