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.

Modulation of Gene Expression by Polyalthia longifolia in Postmenopausal Women with Coronary Artery Disease: An In Vitro Study

“…Similar findings have been reported by Cutolo et al [31], where they reported that treatment of THP-1 cells with phorbol diester 12-O-tetradecanoylphorbol 13-acetate caused early expression of ERα, whereas ERβ was induced later. The possible reason for an early expression of ERα could be that ERα acts as a main Our observations demonstrated decreased expression of both ERα and ERβ receptors in PBMCs of postmenopausal women with CAD as compared to those women without CAD.…”

Sesamin Inhibits Macrophage-Induced Vascular Endothelial Growth Factor and Matrix Metalloproteinase-9 Expression and Proangiogenic Activity in Breast Cancer Cells

“…The macrophages used in this study were derived from human monocytic leukemia THP-1 cell line. After treated with 12-O-tetradecanoyl-13-phorbol acetate (TPA), THP-1 cells were induced to differentiate into macrophages [21] and were confirmed by CD14 + and CD68 + staining and by their capability of ingesting fluorescence-labeled Latex beads (Sigma, St. Louis, MO, USA).…”

Molecular and Cellular Determinants of Estrogen Receptor α Expression

“…Thus, these studies conflict on whether TPA mediates ER mRNA transcriptionally or posttranscriptionally. The effects of TPA on ER have also been examined in leukemia cells (12). In THP-1 cells derived from a patient with acute monocytic leukemia, 50 ng of TPA/ml stimulated ER expression, whereas untreated cells were ER negative.…”

“…In THP-1 cells derived from a patient with acute monocytic leukemia, 50 ng of TPA/ml stimulated ER expression, whereas untreated cells were ER negative. Approximately 60 to 75% of TPA-treated cells stained positively for ER, with the majority of ER seen within the nucleus (12).…”