5a7c
Crystal structure of the second bromodomain of human BRD3 in complex with compound
Structural highlights
DiseaseBRD3_HUMAN Note=A chromosomal aberration involving BRD3 is found in a rare, aggressive, and lethal carcinoma arising in midline organs of young people. Translocation t(15;9)(q14;q34) with NUT which produces a BRD3-NUT fusion protein. FunctionBRD3_HUMAN Binds hyperacetylated chromatin and plays a role in the regulation of transcription, probably by chromatin remodeling and interaction with transcription factors. Regulates transcription by promoting the binding of the transcription factor GATA1 to its targets (By similarity). Regulates transcription of the CCND1 gene.[1] Publication Abstract from PubMedAgents that trigger cell differentiation are highly efficacious in treating certain cancers, but such approaches are not generally effective in most malignancies. Compounds such as DMSO and hexamethylene bisacetamide (HMBA) have been used to induce differentiation in experimental systems, but their mechanisms of action and potential range of uses on that basis have not been developed. Here, we show that HMBA, a compound first tested in the oncology clinic over 25 years ago, acts as a selective bromodomain inhibitor. Biochemical and structural studies revealed an affinity of HMBA for the second bromodomain of BET proteins. Accordingly, both HMBA and the prototype BET inhibitor JQ1 induced differentiation of mouse erythroleukemia cells. As expected of a BET inhibitor, HMBA displaced BET proteins from chromatin, caused massive transcriptional changes, and triggered cell-cycle arrest and apoptosis in Myc-induced B-cell lymphoma cells. Furthermore, HMBA exerted anticancer effects in vivo in mouse models of Myc-driven B-cell lymphoma. This study illuminates the function of an early anticancer agent and suggests an intersection with ongoing clinical trials of BET inhibitor, with several implications for predicting patient selection and response rates to this therapy and starting points for generating BD2-selective BET inhibitors. Cancer Res; 76(8); 2376-83. (c)2016 AACR. Cancer Differentiating Agent Hexamethylene Bisacetamide Inhibits BET Bromodomain Proteins.,Nilsson LM, Green LC, Muralidharan SV, Demir D, Welin M, Bhadury J, Logan DT, Walse B, Nilsson JA Cancer Res. 2016 Apr 15;76(8):2376-83. doi: 10.1158/0008-5472.CAN-15-2721. Epub, 2016 Mar 3. PMID:26941288[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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