Inhibition of super enhancer downregulates the expression of KLF5 in basal-like breast cancers

The transcription factor KLF5 is highly expressed in basal-like breast cancer (BLBC). It promotes cell proliferation, survival, migration and stemness and serves as a potential therapeutic target. In this study, we first identified a super-enhancer (SE) located downstream of the KLF5 gene in BLBC. JQ-1, a BRD4-bromodomain inhibitor, inhibits the expression and activity of KLF5 in the HCC1806 and HCC1937 cell lines in time- and dose-dependent manners. A new BRD4 inhibitor, compound 870, is more potent than JQ-1 in terms of its ability to inhibit KLF5 and BLBC growth by inducing G1 phase cell cycle arrest. Additionally, a CDK7 inhibitor, THZ1, also inhibits KLF5 and BLBC growth. Our findings suggested that SE regulates KLF5 and that SE inhibitors could be an effective therapeutic strategy for treating BLBC. Overall design: ChIP-seq performed in this study was designed to detect the signal of BRD4 and H3K27Ac around KLF5 gene