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.
Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Base Pairing
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Caco-2 Cells
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Calcium Channels / genetics
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Calcium Channels / metabolism
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Cell Differentiation / drug effects
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Cell Differentiation / genetics
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Cell Proliferation / drug effects
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Enzyme Activation / drug effects
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Extracellular Signal-Regulated MAP Kinases / metabolism*
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Gene Expression Regulation, Enzymologic / drug effects*
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Gene Knockdown Techniques
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Humans
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MAP Kinase Signaling System / drug effects
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MAP Kinase Signaling System / genetics
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Phosphorylation / drug effects
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Promoter Regions, Genetic / genetics
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Protein Binding / drug effects
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Receptors, Calcitriol / metabolism
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Sp1 Transcription Factor / metabolism
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Sp3 Transcription Factor / metabolism*
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Steroid Hydroxylases / genetics*
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TRPV Cation Channels / genetics
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TRPV Cation Channels / metabolism
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Tetradecanoylphorbol Acetate / pharmacology*
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Vitamin D / analogs & derivatives*
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Vitamin D / pharmacology
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Vitamin D3 24-Hydroxylase
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p38 Mitogen-Activated Protein Kinases / metabolism
Substances
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Calcium Channels
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RNA, Messenger
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Receptors, Calcitriol
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Sp1 Transcription Factor
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TRPV Cation Channels
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TRPV6 protein, human
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dihydroxy-vitamin D3
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Vitamin D
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Sp3 Transcription Factor
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Steroid Hydroxylases
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CYP24A1 protein, human
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Vitamin D3 24-Hydroxylase
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Extracellular Signal-Regulated MAP Kinases
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p38 Mitogen-Activated Protein Kinases
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Tetradecanoylphorbol Acetate