title: Influence of estrogens and antiestrogens on the expression of selected hormone-responsive genes.
abstract: Estrogen exerts a primary regulatory role on a wide variety of physiological processes in different tissues and organs. Agonistic ad antagonistic compounds are widely used in human health and, therefore, a deep understanding of their mechanisms of action at the molecular level is mandatory. The effect of 17beta-estradiol and three antiestrogenic drugs, comprising two selective estrogen receptor modulator (SERM, 4-OH-tamoxifen, Raloxifene) and the pure antiestrogen ICI 182,780, on genome-wide gene expression levels was evaluated in breast carcinoma cell lines by DNA microarray analysis. Different clusters of genes, showing specific coregulation patterns, were found. First, several groups of genes displaying temporal-specific up- or down-regulation were characterized. Second, clusters of genes responding to different antiestrogenic drugs in either antagonstic or agonistic fashion, were found. Genes responding specifically to antiestrogens, but not to estrogen, were also identified. In addition, each individual compound exhibited a very specific gene regulation. Bioinformatic analysis was applied to the regulatory sequences of different groups of genes and confirmed that specific pathways and secondary responses are activated at each temporal point and in response to different compounds. Our results underline the complexity of genomic responses to estrogen in breast cancer cells and strongly suggest that the molecular characterization of estrogen agonists and antagonists used in human therapy should be carefully studied.
authors: Cattedra di Ginecologia Oncologica, Istituto per la Ricerca e la Cura del Cancro, Università Degli Studi di Torino, Candiolo, Italy. p.sismondi@tin.it
authors: Piero
authors: P
authors: Sismondi
authors: Nicoletta
authors: N
authors: Biglia
authors: Riccardo
authors: R
authors: Ponzone
authors: Luca
authors: L
authors: Fuso
authors: Claudio
authors: C
authors: Scafoglio
authors: Luigi
authors: L
authors: Cicatiello
authors: Maria
authors: M
authors: Ravo
authors: Alessandro
authors: A
authors: Weisz
authors: Daniela
authors: D
authors: Cimino
authors: Gioia
authors: G
authors: Altobelli
authors: Olivier
authors: O
authors: Friard
authors: Michele
authors: M
authors: De Bortoli
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology; D015536:Down-Regulation; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000494:pharmacology*; D005260:Female; D000077267:Fulvestrant; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics; D006801:Humans; D020849:Raloxifene Hydrochloride / Q000494:pharmacology*; D020845:Selective Estrogen Receptor Modulators / Q000494:pharmacology*; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: D004965:Estrogen Antagonists; D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen; C016601:afimoxifene; D000077267:Fulvestrant; D020849:Raloxifene Hydrochloride; D004958:Estradiol