PF-CBP1 HCl is a highly selective inhibitor of the bromodomain of CREB-binding protein(CREBBP). It inhibits CREBBP (IC50: 125 nM) and p300 bromodomains (IC50: 363 nM).

PF-CBP1 modulates key inflammatory genes in primary macrophages. PF-CBP1 down regulates RGS4 in neurons, a target linked to Parkinson's disease. It is 139-fold selective over BRD4 in the biochemical assays and >105-fold selective by ITC. PF-CBP1 is also a potent inhibitor of EP300 and possesses no cytotoxicity in macrophages, and hepatotoxicity in cell-based models as long as the concentration is not very high.

Cells are pretreated with the probes PF-CBP1, ISOX-INACT, or ISOX-DUAL starting at 10 μM concentrations, and then serially diluted to 0.1 μM. After 30 min, the cells are treated with LPS to induce gene transcription and the expression levels of interleukin-6 (IL-6), IL-1β, and interferon-β (IFN-β)(which are known to be induced after 4 h of LPS exposure) are analyzed by RT-PCR. Probe PF-CBP1 moderately reduces LPS-induced IL-6 and IFN-β expression at 10 μM, and a decrease in IL-1β expression is evident at 3 μM.  (Only for Reference)