title: Phorbol diester 12-O-tetradecanoylphorbol 13-acetate (TPA) up-regulates the expression of estrogen receptors in human THP-1 leukemia cells.
abstract: In the present work, we have inspected expression of estrogen receptors (ER) and their regulation by the phorbol diester 12-O-tetradecanoylphorbol 13-acetate (TPA) in a leukemic cell line, the THP-1 cells, using multiple experimental approaches. Firstly, ligand binding assay (LBA) revealed that control (unstimulated) THP-1 cells express type I (high affinity, limited capacity) ER in the nuclear fraction only, whilst treatment of cells with TPA resulted in the appearance of type I ER in the soluble fraction as well, with the 50 ng/ml dose and the 48 h incubation time being the most effective experimental condition. A concomitant increase of type II ER was also seen in both soluble and nuclear cell fractions. Unstimulated THP-1 cells were found to be ER negative by immunocytochemistry; conversely, cells exposed to 50 ng/ml TPA for 48 h stained positively for ER, with the majority of cells having a strong nuclear staining. Scrutiny of ER mRNA expression using reverse transcriptase-polymerase chain reaction showed the presence of a wild type ER transcript in both control and TPA-treated THP-1 cells, though levels of ER mRNA were found to be comparatively higher in the latter. This combined evidence would imply that the TPA-induced differentiation of THP-1 cells is accompanied by the rise of high affinity (type I) ER, suggesting that estrogens may play a role in the regulation of macrophage activity during the inflammatory and/or the immune response.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, University of Genoa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Cutolo
authors.forename: G
authors.initials: G
authors.lastname: Carruba
authors.forename: B
authors.initials: B
authors.lastname: Villaggio
authors.forename: D A
authors.initials: DA
authors.lastname: Coviello
authors.forename: J M
authors.initials: JM
authors.lastname: Dayer
authors.forename: I
authors.initials: I
authors.lastname: Campisi
authors.forename: M
authors.initials: M
authors.lastname: Miele
authors.forename: R
authors.initials: R
authors.lastname: Stefano
authors.forename: L A
authors.initials: LA
authors.lastname: Castagnetta
mesh_terms: D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation; D007700:Kinetics; D007938:Leukemia / Q000378:metabolism*; D008024:Ligands; D012333:RNA, Messenger / Q000378:metabolism; D011960:Receptors, Estrogen / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013997:Time Factors; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: D008024:Ligands; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D013755:Tetradecanoylphorbol Acetate