Phorbol esters enhance 1α,25-dihydroxyvitamin D3-regulated 25-hydroxyvitamin D-24-hydroxylase (CYP24A1) gene expression through ERK-mediated phosphorylation of specific protein 3 (Sp3) in Caco-2 cells

Mol Cell Endocrinol. 2012 Sep 25;361(1-2):31-9. doi: 10.1016/j.mce.2012.03.008. Epub 2012 Mar 28.

Abstract

Phorbol 12-myristate 13-acetate (PMA) increased 1,25(OH)(2)D(3)-induced human 25 hydroxyvitamin d-24 hydroxylase (hCYP24A1) gene expression and vitamin D receptor (VDR) binding to the hCYP24A1 promoter. It did not alter transient receptor potential cation channel, subfamily V, member 6 (TRPV6) expression, VDR binding to the TRPV6 promoter, or VDR binding to a crude chromatin preparation. PMA activated Extracellular signal-Regulated Kinases (ERK) 1/2 and p38 mitogen activated protein kinases (MAPK) and inhibiting these kinases reduced 1,25(OH)(2)D(3)-induced and PMA-enhanced hCYP24A1 promoter activity. Mithramycin A inhibits Specific Protein (Sp) family member binding to DNA and reduced 1,25(OH)(2)D(3)-induced and PMA-enhanced hCYP24A1 promoter activity. Sp1 or Sp3 siRNA knockdown reduced 1,25(OH)(2)D(3)-regulated hCYP24A1 promoter activity but only Sp3 siRNA reduced PMA-enhanced hCYP24A1 promoter activity. PMA increased MAPK-dependent Sp3 phosphorylation, Sp3-VDR interactions, and Sp3 binding to the hCYP24A1 promoter. These data suggest that MAPK signaling contributes to 1,25(OH)(2)D(3)-induced and PMA-enhanced CYP24A1 gene transcription by modulating Sp3 function.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Base Pairing
  • Caco-2 Cells
  • Calcium Channels / genetics
  • Calcium Channels / metabolism
  • Cell Differentiation / drug effects
  • Cell Differentiation / genetics
  • Cell Proliferation / drug effects
  • Enzyme Activation / drug effects
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • Gene Expression Regulation, Enzymologic / drug effects*
  • Gene Knockdown Techniques
  • Humans
  • MAP Kinase Signaling System / drug effects
  • MAP Kinase Signaling System / genetics
  • Phosphorylation / drug effects
  • Promoter Regions, Genetic / genetics
  • Protein Binding / drug effects
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptors, Calcitriol / metabolism
  • Sp1 Transcription Factor / metabolism
  • Sp3 Transcription Factor / metabolism*
  • Steroid Hydroxylases / genetics*
  • TRPV Cation Channels / genetics
  • TRPV Cation Channels / metabolism
  • Tetradecanoylphorbol Acetate / pharmacology*
  • Vitamin D / analogs & derivatives*
  • Vitamin D / pharmacology
  • Vitamin D3 24-Hydroxylase
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Calcium Channels
  • RNA, Messenger
  • Receptors, Calcitriol
  • Sp1 Transcription Factor
  • TRPV Cation Channels
  • TRPV6 protein, human
  • dihydroxy-vitamin D3
  • Vitamin D
  • Sp3 Transcription Factor
  • Steroid Hydroxylases
  • CYP24A1 protein, human
  • Vitamin D3 24-Hydroxylase
  • Extracellular Signal-Regulated MAP Kinases
  • p38 Mitogen-Activated Protein Kinases
  • Tetradecanoylphorbol Acetate