Phorbol diester 12-O-tetradecanoylphorbol 13-acetate (TPA) up-regulates the expression of estrogen receptors in human THP-1 leukemia cells

✍ Scribed by Maurizio Cutolo; Giuseppe Carruba; Barbara Villaggio; Domenico A. Coviello; Jean-Michel Dayer; Ildegarda Campisi; Monica Miele; Rosalba Stefano; Prof. Luigi A.M. Castagnetta

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 307 KB
• Volume: 83
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.1237

✦ Synopsis

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. J. Cell. Biochem. 83: 390–400, 2001. © 2001 Wiley‐Liss, Inc.