title: Targeting 1alpha,25-dihydroxyvitamin D3 antiproliferative insensitivity in breast cancer cells by co-treatment with histone deacetylation inhibitors.
abstract: Proliferation of the non-malignant breast epithelial cell line, MCF-12A, is sensitively and completely inhibited by 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) (ED90 = 70 nM), We used real time RT-PCR to demonstrate that the relative resistance to 1alpha,25(OH)(2)D(3) of MDA-MB-231 cells (ED50 > 100 nM) correlated with significantly reduced Vitamin D receptor (VDR) and increased NCoR1 nuclear receptor co-repressor mRNA (0.1-fold reduction in VDR and 1.7-fold increase in NCoR1 relative to MCF-12A (P < 0.05)). This molecular lesion can be targeted by co-treating cells with 1alpha,25(OH)(2)D(3) or potent analogs and the histone deacetylation inhibitor trichostatin A (TSA). For example, the co-treatment of 1,25-dihydroxy-16,23,Z-diene-26,27-hexafluoro-19-nor Vitamin D(3) (RO-26-2198) (100 nM) plus TSA results in strong additive antiproliferative effects in MDA-MB-231 cells. This may represent novel chemotherapeutic regime for hormone insensitive breast cancer.
authors.affiliation: Department of Medicine, Division of Medical Sciences, Queen Elizabeth Hospital, University of Birmingham Medical School, Edgbaston, Birmingham B15 2TT, UK. claire_banwell@yahoo.com
authors.forename: Claire M
authors.initials: CM
authors.lastname: Banwell
authors.forename: Laura P
authors.initials: LP
authors.lastname: O'Neill
authors.forename: Milan R
authors.initials: MR
authors.lastname: Uskokovic
authors.forename: Moray J
authors.initials: MJ
authors.lastname: Campbell
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology / Q000473:pathology*; D002117:Calcitriol / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; C012589:trichostatin A; D002117:Calcitriol