Identification of vitamin D3 target genes in human breast cancer tissue

J Steroid Biochem Mol Biol. 2016 Nov:164:90-97. doi: 10.1016/j.jsbmb.2015.10.012. Epub 2015 Oct 17.


Multiple epidemiological studies have shown that high vitamin D3 status is strongly associated with improved breast cancer survival. To determine the molecular pathways influenced by 1 alpha, 25-dihydroxyvitamin D3 (1,25D) in breast epithelial cells we isolated RNA from normal human breast and cancer tissues treated with 1,25D in an ex vivo explant system. RNA-Seq revealed 523 genes that were differentially expressed in breast cancer tissues in response to 1,25D treatment, and 127 genes with altered expression in normal breast tissues. GoSeq KEGG pathway analysis revealed 1,25D down-regulated cellular metabolic pathways and enriched pathways involved with intercellular adhesion. The highly 1,25D up-regulated target genes CLMN, SERPINB1, EFTUD1, and KLK6were selected for further analysis and up-regulation by 1,25D was confirmed by qRT-PCR analysis in breast cancer cell lines and in a subset of human clinical samples from normal and cancer breast tissues. Ketoconazole potentiated 1,25D-mediated induction of CLMN, SERPINB1, and KLK6 mRNA through inhibition of 24-hydroxylase (CYP24A1) activity. Elevated expression levels of CLMN, SERPINB1, and KLK6 are associated with prolonged relapse-free survival for breast cancer patients. The major finding of the present study is that exposure of both normal and malignant breast tissue to 1,25D results in changes in cellular adhesion, metabolic pathways and tumor suppressor-like pathways, which support epidemiological data suggesting that adequate vitamin D3 levels may improve breast cancer outcome.

Keywords: Breast cancer; Genomics; Mammary tissue; RNA-Seq; Vitamin D(3).

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Breast / metabolism
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / surgery
  • Calcitriol / pharmacology
  • Cell Adhesion
  • Cell Line, Tumor
  • Cholecalciferol / metabolism*
  • Disease-Free Survival
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Kallikreins / metabolism
  • Ketoconazole / pharmacology
  • MCF-7 Cells
  • Membrane Proteins / metabolism
  • Neoplasm Recurrence, Local
  • Peptide Elongation Factors / metabolism
  • Ribonucleoprotein, U5 Small Nuclear / metabolism
  • Sequence Analysis, RNA
  • Serpins / metabolism
  • Signal Transduction
  • Transcription, Genetic
  • Up-Regulation
  • Vitamin D3 24-Hydroxylase / antagonists & inhibitors


  • Antineoplastic Agents
  • CLMN protein, human
  • EFL1 protein, human
  • Membrane Proteins
  • Peptide Elongation Factors
  • Ribonucleoprotein, U5 Small Nuclear
  • Serpins
  • SERPINB1 protein, human
  • Cholecalciferol
  • CYP24A1 protein, human
  • Vitamin D3 24-Hydroxylase
  • KLK6 protein, human
  • Kallikreins
  • Calcitriol
  • Ketoconazole