The BET (Bromodomain and Extra-Terminal) family of transcription factors includes the bromodomain-containing proteins BRD2, BRD3, BRD4, and BRDT.
BRD proteins associate with acelylated lysine residues on histones in gene promoters and enhancers to recruit transcriptional complexes that regulate the expression of target genes.
BRD targets include genes involved in lineage determination, cellular growth, and survival and inflammation that play important roles in the development and progression of cancer. These genes include C-MYC, MLL, BCL2, cyclin D, IL6, and GLI1.
BRD4 is required for expression of the C-MYC oncogene that is deregulated in many cancers and drives cellular growth and proliferation.
BRDs regulate the activity of other cancer-associated DNA-binding transcription factors including the androgen receptor and NF-κB.
In tumor cells, the inhibition of BRDs may offer a potential avenue to curbing the overexpression and activity of C-MUC and other transcription factors, thereby altering transcriptional networks that are deregulated in cancer.