Regulation of multiple insulin-like growth factor binding protein genes by 1alpha,25-dihydroxyvitamin D3

Nucleic Acids Res. 2005 Sep 26;33(17):5521-32. doi: 10.1093/nar/gki872. Print 2005.

Abstract

Recently, insulin-like growth factor binding proteins (IGFBPs) have been found to be primary mediators of the anti-proliferative actions of the nuclear hormone 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3], but dependent on cellular context IGFBPs can also have a mitogenic effect. In this study, we performed expression profiling of all six human IGFBP genes in prostate and bone cancer cells and demonstrated that IGFBP1, 3 and 5 are primary 1alpha,25(OH)2D3 target genes. In silico screening of the 174 kb of genomic sequence surrounding all six IGFBP genes identified 15 candidate vitamin D response elements (VDREs) close to or in IGFBP1, 2, 3 and 5 but not in the IGFBP4 and 6 genes. The putative VDREs were evaluated in vitro by gelshift assays and in living cells by reporter gene and chromatin immuno-precipitation (ChIP) assays. Of these 10 VDREs appear to be functional. ChIP assays demonstrated for each of these an individual, stimulation time-dependent association profile not only with the vitamin D receptor, but also with first heterodimeric partner the retinoid X receptor, other regulatory complex components and phosphorylated RNA polymerase II. Some of the VDREs are located distantly from the transcription start sites of IGFBP1, 3 and 5, but all 10 VDREs seem to contribute to the regulation of the genes by 1alpha,25(OH)2D3. In conclusion, IGFBP1, 3 and 5 are primary 1alpha,25(OH)2D3 target genes that in intact cells are each under the control of multiple VDREs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bone Neoplasms / genetics
  • Bone Neoplasms / metabolism
  • Calcitriol / pharmacology*
  • Cell Line, Tumor
  • Chromatin / genetics
  • Gene Expression Regulation*
  • Humans
  • Insulin-Like Growth Factor Binding Protein 1 / biosynthesis
  • Insulin-Like Growth Factor Binding Protein 1 / genetics
  • Insulin-Like Growth Factor Binding Protein 2 / biosynthesis
  • Insulin-Like Growth Factor Binding Protein 2 / genetics
  • Insulin-Like Growth Factor Binding Protein 3 / biosynthesis
  • Insulin-Like Growth Factor Binding Protein 3 / genetics
  • Insulin-Like Growth Factor Binding Protein 5 / biosynthesis
  • Insulin-Like Growth Factor Binding Protein 5 / genetics
  • Insulin-Like Growth Factor Binding Proteins / biosynthesis
  • Insulin-Like Growth Factor Binding Proteins / genetics*
  • Male
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / metabolism
  • Vitamin D Response Element

Substances

  • Chromatin
  • Insulin-Like Growth Factor Binding Protein 1
  • Insulin-Like Growth Factor Binding Protein 2
  • Insulin-Like Growth Factor Binding Protein 3
  • Insulin-Like Growth Factor Binding Protein 5
  • Insulin-Like Growth Factor Binding Proteins
  • Calcitriol