title: 1,25-Dihydroxyvitamin D3 up-regulates expression of hsa-let-7a-2 through the interaction of VDR/VDRE in human lung cancer A549 cells.
abstract: OBJECTIVE
  We aim to investigate the relationship between 1,25-(OH)2VD3 and hsa-let-7a in lung cancer A549 cells.
  
  
  METHODS
  Real-time PCR and luciferase reporter assays were used to detect the influence of 1,25-(OH)2VD3 on the expression of hsa-let-7a-2 after A549 cells were treated with 1,25-(OH)2VD3 (10(-8)~10(-6)mol/L). Analysis of the 5.0Kb upstream sequence of the pre-let-7a-2 showed that one vitamin D response element (VDRE) is located in -2066/-2042bp of pre-let-7a-2. Electrophoretic mobility shift assays (EMSA), chromatin immunoprecipitation (ChIP) and luciferase reporter assays were performed to determine whether 1,25-(OH)2VD3 activating vitamin D receptor (VDR) could bind to this VDRE to promote hsa-let-7a-2 expression.
  
  
  RESULTS
  We found that 1,25-(OH)2VD3 could up-regulate the expression of hsa-let-7a-2 in a dose-dependent manner. The results of EMSA and ChIP demonstrated that 1,25-(OH)2VD3/VDR could interact with the VDRE in the upstream of pre-let-7a-2. Luciferase reporter assay showed that this VDRE is a functional cis-element mediating the up-regulation of hsa-let-7a-2 expression induced by 1,25-(OH)2VD3.
  
  
  CONCLUSIONS
  Our data indicated that 1,25-(OH)2VD3 could up-regulate the transcription of hsa-let-7a-2 in lung cancer cells, and the up-regulation of hsa-let-7a-2 expression induced by 1,25-(OH)2VD3 might mediate the anti-proliferation effects of 1,25-(OH)2VD3 in lung cancer cells.
authors.affiliation: Institution of Biochemistry and Molecular Biology, Medical School of Shandong University, Jinan, 250012, China.
authors.forename: Hengyun
authors.initials: H
authors.lastname: Guan
authors.forename: Chunyan
authors.initials: C
authors.lastname: Liu
authors.forename: Zhaobo
authors.initials: Z
authors.lastname: Chen
authors.forename: Lina
authors.initials: L
authors.lastname: Wang
authors.forename: Chaoyang
authors.initials: C
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Zhao
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.forename: Pengju
authors.initials: P
authors.lastname: Zhang
authors.forename: Weiwen
authors.initials: W
authors.lastname: Chen
authors.forename: Anli
authors.initials: A
authors.lastname: Jiang
mesh_terms: D002117:Calcitriol / Q000494:pharmacology / Q000502:physiology*; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism*; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D011485:Protein Binding; D018167:Receptors, Calcitriol / Q000378:metabolism*; D015533:Transcriptional Activation; D015854:Up-Regulation; D030181:Vitamin D Response Element / Q000235:genetics*
chemical_list: D035683:MicroRNAs; D018167:Receptors, Calcitriol; C579457:VDR protein, human; C487931:mirnlet7 microRNA, human; D002117:Calcitriol