KISS1 is down-regulated by 17beta-estradiol in MDA-MB-231 cells through a nonclassical mechanism and loss of ribonucleic acid polymerase II binding at the proximal promoter.
Kisspeptins are hypothalamic neuropeptides encoded by KISS1 and recently described as major regulators of GnRH release from hypothalamic neurons. Although 17beta-estradiol (E2)-induced up-regulation of KISS1 expression has been documented in anteroventral periventricular nucleus neurons, E2 down-regulates KISS1 expression in arcuate nucleus neurons via the estrogen receptor alpha by unknown molecular mechanisms. Because KISS1 was initially described as a metastasis inhibitor, notably in breast tumors, we used the MDA-MB-231 breast cancer cell line, which expresses high levels of KISS1, to characterize the molecular mechanism underlying KISS1 regulation by E2. E2 rapidly down-regulated endogenous KISS1 in a stable ERalpha-expressing MDA-MB-231 cell line. Promoter analysis revealed that E2 down-regulation was determined by a short 93-bp sequence devoid of estrogen response element and Sp1 sites. E2 down-regulation persisted with an ERalpha that was unable to bind DNA and in the presence of histone deacetylase inhibitor. In the absence of E2, unliganded ERalpha and RNA polymerase II (RNAPII) were present on the proximal promoter. E2 stimulation induced recruitment of ERalpha and loss of RNAPII at the proximal promoter. Along the gene body, total RNAPII amounts were similar in E2-treated and untreated cells, whereas the active form was significantly less abundant in E2-treated cells. Thus, E2-induced down-regulation of KISS1 is mediated by a pathway combining RNAPII loss at the proximal promoter and modulation of active RNAPII along the gene body, which is a novel mechanism in the complex process of E2-induced repression of gene expression.
Avenir Team Genetic and Physiology of the Onset of Puberty, Institut National de la Santé et de laRecherche Médicale Unité 676, Hopital Robert Debré, and Université Paris Diderot, 75019 Paris, France.
Lukas
L
Huijbregts
Nicolas
N
de Roux
D001665:Binding Sites / Q000187:drug effects; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002277:Carcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000378:metabolism / Q000502:physiology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D059648:Kisspeptins; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D012319:RNA Polymerase II / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism
D047628:Estrogen Receptor alpha; C106628:KISS1 protein, human; D059648:Kisspeptins; D025521:Tumor Suppressor Proteins; D004958:Estradiol; D012319:RNA Polymerase II