Non-overlapping Control of Transcriptome by Promoter- and Super-Enhancer-Associated Dependencies in Multiple Myeloma.

Summary The relationship between promoter proximal transcription factor-associated gene expression and super-enhancer-driven transcriptional programs are not well defined. However, their distinct genomic occupancy suggests a mechanism for specific and separable gene control. We explored the transcriptional and functional interrelationship between E2F transcription factors and BET transcriptional co-activators in multiple myeloma. We found that the transcription factor E2F1 and its heterodimerization partner DP1 represent a dependency in multiple myeloma cells. Global chromatin analysis reveals distinct regulatory axes for E2F and BETs, with E2F predominantly localized to active gene promoters of growth and/or proliferation genes and BETs disproportionately at enhancer-regulated tissue-specific genes. These two separate gene regulatory axes can be simultaneously targeted to impair the myeloma proliferative program, providing an important molecular mechanism for combination therapy. This study therefore suggests a sequestered cellular functional control that may be perturbed in cancer with potential for development of a promising therapeutic strategy. Graphical Abstract Highlights • E2F1 and its heterodimerization partner DP1 are required for myeloma cell proliferation • E2F1-DP1 heterodimers regulate promoter proximal transcription • E2F1 and BRD4 establish distinct regulatory axes in multiple myeloma • Combined inhibition of BRD4 and E2F co-operatively reduces myeloma tumor growth Uncontrolled proliferation is a hallmark of tumorigenesis and is associated with perturbed transcriptomic profile. Fulciniti et al. explored the interrelationship between E2F transcription factors and BET transcriptional co-activators in multiple myeloma, reporting the existence of two distinct regulatory axes that can be synergistically targeted to impact myeloma growth and survival. [ABSTRACT FROM AUTHOR]