Background:

(-)-JQ1 is the stereoisomer of JQ1, a cell-permeable small-molecule inhibitor of BET bromodomain that competitively binds to acetyl-lysine recognition motifs. JQ1 is a novel thieno-triazolo-1,4-diazepine with an appended and bulky t-butyl ester functional group at C6 position in its chemical structure, which allows for additional pendant group diversity and mitigates binding to the central benzodiazepine receptor. JQ1 competitively binds to the bromodomain displacing the BRD4 fusion oncoprotein from chromatin, which induces squamous differentiation and specific anti-proliferative effect in BRD4-dependent cell lines and patient-derived xenograft models. However, study results have shown that (-)-JQ1 fails to significantly interact with any bromodomain tested and exhibits inhibition against BRD4(1) with 50% inhibition concentration IC50 value of 10,000 nM.

Reference

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