Regulation of functional steroid receptors and ligand-induced responses in telomerase-immortalized human endometrial epithelial cells

Abstract

Information on the regulation of steroid hormone receptors and their distinct functions within the human endometrial epithelium is largely unavailable. We have immortalized human primary endometrial epithelial cells (EECs) isolated from a normal proliferative phase endometrium by stably transfecting the catalytic subunit (hTERT) of the human telomerase complex and cultured these hTERT-EECs now for over 350 population doublings. Active hTERT was detected in hTERT-EECs employing the telomerase repeat amplification assay protocol. hTERT-EECs revealed a polarized, non-invasive epithelial phenotype with apical microvilli and production of a basal lamina when grown on a three-dimensional collagen-fibroblast lattice. Employing atomic force microscopy, living hTERT-EECs were shown to produce extracellular matrix (ECM) components and ECM secretion was modified by estrogen and progesterone (P4). hTERT-EECs expressed inducible and functional endogenous estrogen receptor-alpha (ER-alpha) as demonstrated by estrogen response element reporter assays and induction of P4 receptor (PR). P4 treatment down-regulated PR expression, induced MUC-1 gene activity and resulted in increased ER-beta transcriptional activity. Gene activities of cytokines and their receptors interleukin (IL)-6, leukemia inhibitory factor (LIF), IL-11 and IL-6 receptor (IL6-R), LIF receptor and gp130 relevant to implantation revealed a 17 beta-estradiol (E2)-mediated up-regulation of IL-6 and an E2-and P4-mediated up-regulation of IL6-R in hTERT-EECs. Thus, hTERT-EECs may be regarded as a novel in vitro model to investigate the role of human EECs in steroid hormone-dependent normal physiology and pathologies, including implantation failure, endometriosis and endometrial cancer.

Innate immune mediator profiles and their regulation in a novel polarized immortalized epithelial cell model derived from human endocervix

“…All hormone concentrations and protocols were chosen based upon hormone receptor expression studies performed in vitro in endometrial epithelial cells (Hombach-Klonisch et al, 2005), and are within the concentration range reported to be found in endometrial tissue (Nussey and Whitehead, 2001). …”

Basal and Steroid Hormone-Regulated Expression of CXCR4 in Human Endometrium and Endometriosis

“…37,38 All cells were maintained at 37°C in a humidified incubator with 5% CO 2 . For the steroid hormone treatments, 1 million cells were plated per well on a 6-well plate in 10% fetal bovine serum (FBS) media for 24 hours.…”

Bisphenol A modulates receptivity and secretory function of human decidual cells: an in vitro study

“…Progesterone (P 4 ) induces cell differentiation in the estrogen-primed endometrium during the secretory phase; it also prepares epithelial cells for blastocyst attachment and provokes decidualization in stromal cells (Hombach-Klonisch et al 2005). The concerted action of estrogens and P 4 is of paramount importance for endometrial receptivity to the embryo (Sharkey & Smith 2003).…”

“…Endometrial stromal cells were isolated as described by Hombach-Klonisch et al (2005) with some modifications (Mannelli et al 2014). The purity of the stromal cells from each specimen was confirmed by immunocytochemistry using vimentin staining and flow cytometry as previously described (Mannelli et al 2014).…”