Deregulation of the Ras-Erk Signaling Axis Modulates the Enhancer Landscape [ChIP-seq]

Unrestrained receptor tyrosine kinase (RTK) signaling and epigenetic deregulation are root causes of tumorigenesis. We establish linkage between these processes by demonstrating that aberrant RTK signaling unleashed by oncogenic HRasG12V or loss of negative feedback through Sprouty gene deletion remodels histone modifications associated with active typical and super-enhancers. However, while both lesions disrupt the Ras-Erk axis, the expression programs, enhancer signatures, and transcription factor networks modulated upon HRasG12V-transformation or Sprouty deletion are largely distinct. Oncogenic HRasG12V elevates histone 3 lysine 27 acetylation (H3K27ac) levels at enhancers near the transcription factor Gata4 and the kinase Prkcb, as well as their expression levels. We show that Gata4 is necessary for the aberrant gene expression and H3K27ac marking at enhancers, and Prkcb is required for the oncogenic effects of HRasG12V-driven cells. Taken together, our findings demonstrate that dynamic reprogramming of the cellular enhancer landscape is a major effect of oncogenic RTK signaling. Overall design: We performed ChIP-seq to assess the global changes in the histone modifications H3K27ac (AC), H3K4me1 (me1), and H3K4me3 (me3) upon loss of feedback regulation through Sprouty (Spry) deletion, and upon unrestrained signaling driven by oncogenic HRasG12V. ChIP-seq was performed in biological duplicate; replicate2 is indicated in the sample name. Spry124fl/fl (VEC) and Spry124-/- (CRE) MEFs were profiled in three conditions: unsynchronized (U), serum starved (S), and serum starved and FGF treated (F). Spry124fl/fl (VEC) MEFs transduced with empty vector (EV) control or HRasG12V (HRas) were profiled in the unsynchronized state.