Project description:<p>In order to enhance our understanding of the genetic etiology of breast cancer, this study analyzed 1,265,548 Hapmap3 single-nucleotide polymorphisms (SNP) among a discovery set of 3,523 EOBC incident cases and 2,702 age-matched population control women, all of whom were age 50 or younger at enrollment. Subjects were recruited from the eight sites, some of which oversampled cases with a personal or family history of breast cancer.</p>
Project description:Estrogen (E2)-dependent gene regulation mediated by estrogen receptor alpha (ERα) plays a mitogenic role in ER-positive breast cancer cells. Although clinical applications of selective estrogen receptor modulators (SERMs), which directly interact with ERα to alter ERα activity, have been effective as a first line of treatment for breast cancer patients, a large subset of the patients will develop resistance after prolonged use of SERMs. Thus, there is a great need to develop alternative therapeutic strategies for SERM-resistant breast cancers. Here, we describe the potential use of the bromodomain family member protein (BRD) selective bromodomain inhibitor, JQ1, to alter E2-dependent gene expression program and inhibit E2-dependent growth of breast cancer cells. We show that each family member has partially redundant roles as ERα coregulators that are required for ERα-mediated gene transcription. Furthermore, we demonstrate the function of BRD3 as a molecular sensor of total BRD activity by the compensatory control of its protein levels. In addition, BRD3 colocalizes with a subset of ERα binding sites (ERBSs) that are enriched for active enhancer features and associated with highly E2-induced genes. Collectively, we illustrate a critical role of the BET family members in ERα dependent gene expression.
