Targeting histone H2B acetylated enhanceosomes via p300/CBP degradation in prostate cancer (ATAC-Seq)
Prostate cancer (PCa) is driven by oncogenic transcription factor enhanceosomes comprising chromatin and epigenetic regulators. The lysine acetyltransferases p300 and CBP are key cofactors that activate enhancers through histone acetylation. Here, we identify p300/CBP-mediated multisite acetylation of the histone H2B N-terminus (H2BNTac) as a defining feature of oncogenic enhanceosomes in androgen receptor (AR)-positive prostate cancerPCa. p300/CBP are essential for AR and ERG transcriptional activity, and their dual degradation eliminates H2BNTac and H3K27ac marks at hyperactive enhancers, leading to stronger suppression of oncogenic transcription more effectively than targeting either paralog or bromodomains alone. Cytotoxicity profiling across >900 cell lines revealed that tumors with high H2BNTac, including AR-positive prostate cancerPCa, are selectively dependent on p300/CBP. In preclinical models, systemic p300/CBP degradation inhibited tumor growth, synergized with AR antagonists, and showed no evident toxicity. These findings position H2BNTac as an  key epigenetic marker of enhancer addiction and establish support dual p300/CBP degradation as a promising therapeutic strategypy for enhancer-driven cancers. Overall design: Distinct prostate cancer cells were treated in vitro with the 100nM p300/CBP degrader CBPD-409 (abbreviated as CBPD), 1uM p300/CBP inhibitor,  CCS1477 (abbreviated as CCS), 1uM  p300/CBP inhibitor,  GNE-049 (abbreviated as GNE) or 1uM SAMARCA2/4 degrader AU15330 (abbreviated as AU) for indicated durations, and processed for multi-omic characterization.