title: Epigenetic modulation of estrogen receptor-alpha by pRb family proteins: a novel mechanism in breast cancer.
abstract: Estrogen receptor-alpha (ER-alpha) plays a crucial role in normal breast development and has also been linked to mammary carcinogenesis and clinical outcome in breast cancer patients. However, ER-alpha gene expression can change during the course of disease and, consequently, therapy resistance can occur. The molecular mechanism governing ER-alpha transcriptional activity and/or silencing is still unclear. Here, we showed that the presence of a specific pRb2/p130 multimolecular complex on the ER-alpha promoter strongly correlates with the methylation status of this gene. Furthermore, we suggested that pRb2/p130 could cooperate with ICBP90 (inverted CCAAT box binding protein of 90 kDa) and DNA methyltransferases in maintaining a specific methylation pattern of ER-alpha gene. The sequence of epigenetic events for establishing and maintaining the silenced state of ER-alpha gene can be locus- or pathway- specific, and the local remodeling of ER-alpha chromatin structure by pRb2/p130 multimolecular complexes may influence its susceptibility to specific DNA methylation. Our novel hypothesis could provide a basis for understanding how the complex pattern of ER-alpha methylation and transcriptional silencing is generated and for understanding the relationship between this pattern and its function during the neoplastic process.
authors: Sbarro Institute for Cancer Research and Molecular Medicine, Center of Biotechnology, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, USA. macaluso@temple.edu
authors: Marcella
authors: M
authors: Macaluso
authors: Micaela
authors: M
authors: Montanari
authors: Paul Bart
authors: PB
authors: Noto
authors: Valter
authors: V
authors: Gregorio
authors: Christian
authors: C
authors: Bronner
authors: Antonio
authors: A
authors: Giordano
mesh_terms: D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D001943:Breast Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D019175:DNA Methylation; D000077209:Decitabine; D050881:E1A-Associated p300 Protein / Q000378:metabolism; D047628:Estrogen Receptor alpha / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D011401:Promoter Regions, Genetic; D016160:Retinoblastoma Protein / Q000235:genetics* / Q000378:metabolism; D050720:Retinoblastoma-Like Protein p107 / Q000378:metabolism; D050717:Retinoblastoma-Like Protein p130 / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D047628:Estrogen Receptor alpha; D016160:Retinoblastoma Protein; D050720:Retinoblastoma-Like Protein p107; D050717:Retinoblastoma-Like Protein p130; D000077209:Decitabine; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D050881:E1A-Associated p300 Protein; C494360:EP300 protein, human; C406364:UHRF1 protein, human; D044767:Ubiquitin-Protein Ligases; D001374:Azacitidine