Steroid hormones modulate H19 gene expression in both mammary gland and uterus

Abstract

H19 is an imprinted and developmentally regulated gene whose product remains apparently untranslated. In a previous study on breast adenocarcinomas, we reported that overexpression of the H19 gene was signi®cantly correlated with the presence of steroid receptors, suggesting the putative role of hormones in H19 transcription. To determine the mode of steroid action, we have detected levels of H19 RNA synthesis during mammary gland development by in situ hybridization (ISH): two peaks of H19 transcription occur during puberty and pregnancy. Furthermore, we demonstrated by ISH that in the uterus H19 RNA synthesis is high during estrus and metestrus phases. To test steroid control of H19 transcription, ovariectomized and adrenalectomized mice were supplemented, 1 week after surgery, with 17-b-estradiol (E2, 20 mg/kg/day), progesterone (P, 1 mg/kg/day) or corticosterone (B, 0.3 mg/ kg/day) for 2 weeks. According to ISH data, E2 and to a lesser extent B stimulated H19 transcription in the uterus, whereas P inhibited it. To con®rm the in vivo results, in vitro experiments were performed using cultures of MCF-7 cells (a hormone-sensitive mammary cell line). E2 stimulated the endogenous H19 gene of this cell line and tamoxifen inhibited this e ect. Furthermore, we performed transient cotransfections in MCF-7, in HBL-100 (another hormone-sensitive mammary cell line) and in BT-20 (a hormone-insensitive mammary cell line) with various constructs of ERa (WT or mutated) and PR-A, in presence or absence of steroid hormones. We demonstrated that ERa up-regulated the H19 promoter in MCF-7 and in HBL-100, whereas PR-A did not have any e ect per se. Moreover, in MCF-7, PR-A antagonized clearly the ERa-mediated promoter enhancement, but in HBL-100 this counteracting e ect on the ERa up-regulation was not found. Interestingly, the same experiments performed in BT-20 cell line provided very similar results as those obtained in MCF-7 cells, with a clear down-regulation mediated by PR-A on the H19 promoter. All these in vitro data are in agreement with in vivo results. In addition, data obtained with ERa mutants indicate that H19 promoter activation is both ligand-dependent and ligand-independent. We have thus demonstrated that H19 gene expression is controlled by steroid hormones; furthermore, this gene is highly expressed in hormone-sensitive organs when the hormonal stimulation is accompanied with a morphological repair.

Imprinted gene expression in the rat embryo–fetal axis is altered in response to periconceptional maternal low protein diet

“…In mouse uterus, it has been shown that 17b-estradiol enhances H19 expression, whereas progesterone represses it through their effect on the H19 promoter (Adriaenssens et al 1999). In the present study, however, neither 17b-estradiol nor progesterone levels in serum from pregnant dams was affected by LPD.…”

“…A previous study has shown that steroid hormones alter the expression of H19 gene in the uterus and in hormone-sensitive mammary MCF-7 cells (Adriaenssens et al 1999). To investigate the possibility that reduction in H19 expression in blastocysts may result from alteration in maternal steroid hormone concentrations, these were measured in day 4 maternal serum.…”

Progesterone Receptor A and B Isoforms in the Human Breast and Its Disorders

“…24) In addition, PRA has been reported to suppress the expression of ERα through the H19 promoter in both hormone-sensitive and hormone-insensitive breast cancer cell lines. 26) These findings suggest the possible inhibitory and/or suppressive nature of PRA in the biological actions of progesterone and/or other steroids. However, Chalbos and Galtier have reported that PRB, but not PRA, inhibits gene transcription induced by ER.…”

Thioredoxin post-transcriptional regulation by H19 provides a new function to mRNA-like non-coding RNA

“…H19 gene is abundantly expressed in both extraembryonic and fetal tissues and its transcripts accumulate in tissues of endodermal and mesodermal origin (Pachnis et al, 1988;Poirier et al, 1991;Rachmilewitz et al, 1992). After birth the gene is repressed in almost all tissues, but its transcripts remain detectable in a few adult organs, in particular mammary gland (Adriaenssens et al, 1999). Furthermore, H19 gene activation has been reported in various cancer tissues (Douc-Rasy et al, 1993;Dugimont et al, 1995;Elkin et al, 1995;Kondo et al, 1995;Ariel et al, 1997).…”

“…For Northern blot analysis, total RNA was extracted using the RNeasy Mini Kit (QIAGEN SA). RNA (20 mg) was denaturated, electrophoresed through a 1.2% agarose gel containing formaldehyde, transferred and hybridized as previously described (Adriaenssens et al, 1999) The H19 gene up-regulates thioredoxin S Lottin et al Figure 2 Thioredoxin is up-regulated in H19-transfected MDA-MB-231 breast cancer cells. (a) 2D electrophoresis pro®l of 35 Slabelled proteins from control MDA cells.…”