Therapeutic targeting of BET bromodomain and other epigenetic acetylrecognition domain–containing factors

Development of cancer therapies targeting chromatin modifiers and transcriptional regulatory factors is rapidly expanding to include new targets and novel targeting strategies. At the same time, basic molecular research continues to refine our understanding of the epigenetic mechanisms regulating transcription, gene expression, and oncogenesis. This mini-review focuses on cancer therapies targeting the chromatin-associated factors that recognize histone lysine acetylation. Recently reported safety and efficacy are discussed for inhibitors targeting the bromodomains of bromodomain and extraterminal domain (BET) family proteins. In light of recent results indicating that the transcriptional regulator BRD4-PTEFb can function independently of BRD4's bromodomains, the clinical trial performance of these BET inhibitors is placed in a broader context of existing and potential strategies for targeting BRD4-PTEFb. Recently developed therapies targeting bromodomain-containing factors within the SWI/SNF (BAF) family of chromatin remodeling complexes are discussed, as is the potential for targeting the bromodomain-containing transcription factor TAF1 and the YEATS acetylrecognition domain–containing factor GAS41. Recent findings regarding the selectivity and combinatorial specificity of acetylrecognition are highlighted. In conclusion, the potential for further development is discussed with a focus on proximity-based therapies targeting this class of epigenetic factors.