title: Silencing and re-expression of retinoic acid receptor beta2 in human melanoma.
abstract: Many melanoma cells are resistant to the anti-proliferative effect of all trans retinoic acid (ATRA). Retinoic Acid Receptor-beta2 (RAR-beta2) mediates the ATRA growth inhibition. We found a correlation between the anti-proliferative activity of ATRA and expression of RAR-beta2. There was not a strict correlation between DNA methylation of RAR-beta gene and its expression. There was no difference in global and RARbeta specific nucleosome repeat length (NRL) in melanoma and melanocytes or between control and ATRA treated cells. Pan-acetylation of H3 and H4 within the RAR-beta gene promoter was higher in cells expressing RAR-beta2. All trans retinoic acid treatment of responsive cells did not change pan-acetylation of H3/H4, but addition of ATRA to non-responsive cells increased H4 pan-acetylation. Phytochemicals or the histone deacetylase inhibitor Trichostatin A did not restore expression of RAR-beta2. Treatment of WM1366 melanoma cells with 5-aza 2'-deoxycytidine reactivated RAR-beta2 gene expression and restored the ability of ATRA to further induce the expression of this gene. Therefore, promoter methylation is responsible for silencing of RAR-beta2 in some melanoma cells and pan-acetylation of H3 likely plays a permissive role in expression of RAR-beta2.
authors.affiliation: Department of Biochemistry & Microbiology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Fan
authors.forename: Linda
authors.initials: L
authors.lastname: Eastham
authors.forename: Melinda E
authors.initials: ME
authors.lastname: Varney
authors.forename: Adam
authors.initials: A
authors.lastname: Hall
authors.forename: Nicolas L
authors.initials: NL
authors.lastname: Adkins
authors.forename: Lora
authors.initials: L
authors.lastname: Chetel
authors.forename: Vincent E
authors.initials: VE
authors.lastname: Sollars
authors.forename: Philippe
authors.initials: P
authors.lastname: Georgel
authors.forename: Richard M
authors.initials: RM
authors.lastname: Niles
mesh_terms: D000107:Acetylation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D047369:Chromatin Immunoprecipitation; D019175:DNA Methylation / Q000187:drug effects; D018450:Disease Progression; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D006657:Histones / Q000378:metabolism; D006801:Humans; D008544:Melanocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008545:Melanoma / Q000235:genetics* / Q000473:pathology; D009707:Nucleosomes / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018168:Receptors, Retinoic Acid / Q000235:genetics* / Q000378:metabolism; D012878:Skin Neoplasms / Q000235:genetics* / Q000473:pathology; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D006657:Histones; D009707:Nucleosomes; D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; C540966:retinoic acid receptor, beta2, human; D014212:Tretinoin