title: Vitamin D3 receptor/Sp1 complex is required for the induction of p27Kip1 expression by vitamin D3.
abstract: 1alpha,25-dihydroxyvitamin D3 (vitamin D3) has been shown to upregulate p27Kip1 expression via Sp1 and NF-Y binding sites in the p27Kip1 promoter. However, whether vitamin D3 receptor (VDR) involves in this process is unclear. In this study, we demonstrated that expression of VDR in SW620 cells, which exhibited low level of endogenous VDR, increased vitamin D3-stimulated p27Kip1 promoter activity. On the contrary, suppression of Sp1 expression by small interference RNA reduced the stimulation of p27Kip1 promoter activity by vitamin D3 in LNCaP cells. DNA affinity precipitation assay and chromatin immunoprecipitation assay showed that VDR bound to the p27Kip1 promoter in vitro and in vivo. In addition, we also demonstrated that VDR interacted with Sp1 in vitro and in cells. Collectively, our results suggest that VDR is involved in the induction of p27Kip1 by vitamin D3 and may interact with Sp1 to modulate the expression of target genes that lack VDR response element (VDRE) in their promoters.
authors.affiliation: Graduate Institute of Medicine, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan, Republic of China.
authors.forename: Yu-Chun
authors.initials: YC
authors.lastname: Huang
authors.forename: Jing-Yi
authors.initials: JY
authors.lastname: Chen
authors.forename: Wen-Chun
authors.initials: WC
authors.lastname: Hung
mesh_terms: D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002762:Cholecalciferol / Q000494:pharmacology; D003110:Colonic Neoplasms; D050760:Cyclin-Dependent Kinase Inhibitor p27; D017931:DNA Primers; D017930:Genes, Reporter; D006801:Humans; D008297:Male; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms; D034741:RNA, Small Interfering / Q000235:genetics; D018167:Receptors, Calcitriol / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D017931:DNA Primers; D034741:RNA, Small Interfering; D018167:Receptors, Calcitriol; D011993:Recombinant Fusion Proteins; D016329:Sp1 Transcription Factor; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D002762:Cholecalciferol