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.
Project description:Small GTPase proteins usually serve as molecular switches in various biological process, such as the proliferation, survival, and migration of cells. Mutations or aberrant activations of small GTPase proteins, such as Ras, are frequently observed in various kinds of cancers. Drug discovery efforts that target the Ras family proteins are making breakthroughs, while the discovery of efficient inhibitors that target the Rho family proteins is still stagnant. Protein members from the Rho family, such as RhoA and Cdc42, are key regulators of the migration and invasion of cancer cells. Thus inhibitors of the Rho family proteins are promising to become drug candidates that target cancer metastasis, which is a principal cause of cancer recurrence and chemotherapy failure. Here we show the discovery and characterization of a novel covalent inhibitor named DC-RC-063 that targets the Rho family proteins, using a combined approach of computations and experiments. Revealed by solved crystal structures, compound DC-RC-063 inhibited the activation of RhoA, by disrupting protein-protein interactions, in an allosteric manner. As compound DC-RC-063 inhibited the migration and invasion of breast cancer MDA-MB-231 cells, our findings proved that the Rho family proteins are targetable for covalent inhibitors via an allosteric mechanism. The novel binding site revealed by this inhibitor can be exploited for further development of anti-cancer drugs that target cancer metastasis.
