BET domain co-regulators in obesity, inflammation and cancer

Abstract

Mammalian BET proteins, a class of transcriptional co-regulators that contain dual, mutually related bromodomain motifs and an extraterminal domain, are important in the control of networks of genes; these proteins bind to acetylated lysines in the histones of nucleosomal chromatin, recruit chromatin-modification enzymes to target promoters and function as co-activators or co-repressors of gene expression, depending on the context. New small-molecule inhibitors have recently been developed that disrupt the binding interface between the bromodomain and the acetylated lysine groups; the inhibitors have remarkable potency, selectivity and are well tolerated. They have recently been used as anticancer and anti-inflammatory agents. These developments are important because chromatin was not considered to be a druggable target; as a result of these new drugs, a whole field of new epigenetically targeted therapeutics has become available for investigation. As this field of therapeutics rapidly expands, several features of BET protein function will need to be considered, including possible redundancy among the closely related family members, the selectivity of next-generation agents for specific BET proteins, and possible undesirable consequences of systemic administration without cellular targeting. These side effects might include uncontrolled transcriptional derepression of genes, altered haematopoiesis, immunosuppression or reactivation of latent viruses.