title: G2/M arrest by 1,25-dihydroxyvitamin D3 in ovarian cancer cells mediated through the induction of GADD45 via an exonic enhancer.
abstract: 1,25-Dihydroxyvitamin D3 suppresses the growth of multiple human cancer cell lines by inhibiting cell cycle progression and inducing cell death. The present study showed that 1,25-dihydroxyvitamin D3 causes cell cycle arrest at the G2/M transition through p53-independent induction of GADD45 in ovarian cancer cells. Detailed analyses have established GADD45 as a primary target gene for 1,25-dihydroxyvitamin D3. A DR3-type vitamin D response element was identified in the fourth exon of GADD45 that forms a complex with the vitamin D receptor.retinoid X receptor heterodimer in electrophoresis mobility shift assays and mediates the dose-dependent induction of luciferase activity by 1,25-dihydroxyvitamin D3 in reporter assays. Chromatin immunoprecipitation assays have shown that the vitamin D receptor is recruited in a ligand-dependent manner to the exonic enhancer but not to the GADD45 promoter regions. In ovarian cancer cells expressing GADD45 antisense cDNA or GADD45-null mouse embryo fibroblasts, 1,25-dihydroxyvitamin D3 failed to induce G2/M arrest. Taken together, these results identify GADD45 as an important mediator for the tumor-suppressing activity of 1,25-dihydroxyvitamin D3 in human ovarian cancer cells.
mesh_terms: D020413:3' Untranslated Regions; D015152:Blotting, Northern; D002117:Calcitriol / Q000494:pharmacology*; D016923:Cell Death; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000378:metabolism; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D004742:Enhancer Elements, Genetic; D005091:Exons; D005260:Female; D005434:Flow Cytometry; D016195:G2 Phase; D017930:Genes, Reporter; D016678:Genome; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D007438:Introns; D008024:Ligands; D008156:Luciferases / Q000378:metabolism; D008938:Mitosis; D008954:Models, Biological; D008957:Models, Genetic; D016297:Mutagenesis, Site-Directed; D016376:Oligonucleotides, Antisense / Q000737:chemistry / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection; D015854:Up-Regulation; D000097642:GADD45 Proteins
chemical_list: D020413:3' Untranslated Regions; D002117:Calcitriol; D002843:Chromatin; D018076:DNA, Complementary; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D008156:Luciferases; D016376:Oligonucleotides, Antisense; D011506:Proteins; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D000097642:GADD45 Proteins