Xenoestrogen-induced epigenetic repression of non-coding microRNA genes in breast epithelial cells

Early exposure to xenoestrogens may predispose to breat cancer risk later in adult life. The long-lived, self-regenerating epithelial progenitor cells are more susceptible to these exposure injuries and transmit the injured memory throught epigenetic mechanisms to their differentiated progeny. We have established a breast progenitor model for epigenetic study and our previous work demonstrated that DNA methylation profiling of epithelial progeny derived from progenitors exposed to estradiol detected hypermethylated loci in 0.5% of protein-coding genes. In this study, we extended this exposure study to non-coding microRNA genes. Three mammosphere-derived epithelial cell (MDEC) sample sets from three independent patients. Each sample set includes one DES-preexposed and one DMSO-preexposed MDEC.