title: 1α-Dihydroxyvitamin D3 and Retinoic Acid Increase Nuclear Vitamin D Receptor Expression in Monocytic THP-1 Cells.
abstract: 1α,25-Dihydroxyvitamin D3[1,25(OH)2D3] and retinoic acid, such as all-trans retinoic acid (ATRA) and 9-cis retinoic acid (9cRA), are known to induce differentiation of myeloid leukemia cells. Combined treatment effectively enhances the differentiation effect, particularly in monocytic leukemia cells. The underlying mechanism of this combined effect remains unknown.
  
  
  
  THP-1 monocytic leukemia cells were treated with 1,25(OH)2D3in combination with 9cRA, ATRA or selective synthetic ligand for retinoic acid receptor (RAR) or retinoid X receptor (RXR), and the nuclear expression and function of vitamin D receptor (VDR) were examined.
  
  
  
  Combined treatment with 1,25(OH)2D3and RAR ligand, not RXR ligand, effectively increased nuclear VDR expression and induced expression of the VDR target gene cathelicidin antimicrobial peptide (CAMP) in a gene-selective manner.
  
  
  
  Combination of 1,25(OH)2D3plus RAR ligand is effective in induction of nuclear VDR expression and of target gene.
authors.affiliation: Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, Tokyo, Japan.|Dr. Uchida's ENT Clinic, Atami, Japan.
authors.forename: Hikaru
authors.initials: H
authors.lastname: Uchida
authors.affiliation: Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Hasegawa
authors.affiliation: Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, Tokyo, Japan.|Division of Hematology and Rheumatology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, Tokyo, Japan makishima.makoto@nihon-u.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Makishima
mesh_terms: D002117:Calcitriol / Q000494:pharmacology*; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D018167:Receptors, Calcitriol; D014212:Tretinoin; D002117:Calcitriol
keywords: VDR; antimicrobial peptide; monocyte; retinoic acid; vitamin D