Biological Activity:

CPI203 is a novel potent, selective and cell permeable inhibitor of the bromodomain and extra terminal (BET) family protein BRD4 with an IC₅₀ of ~37 nM (BRD4 α-screen assay). It has an IC₅₀ of ~99 nM in inhibiting Myc expression in MV4-11 cells and an IC₅₀ of ~30 nM in inhibiting IL-6 production in THP-1 cells stimulated with LPS, decreases specific Ser2 phosphorylation of the carboxyl-terminal domain (CTD) of the RNA polymerase II (Pol II) by either endogenous BRD4 or a BRD4 mutant, BRD4 FEE-AAA, that is incapable of binding PTEFb. CPI203 is an analog of JQ-1 but has shown superior bioavailability with oral or intraperitoneal (IP) administration. When mice that were transplanted with primary mouse T-ALL cells, either Fbxw7+/+ or Fbxw7mut/+, were treated with CPI203 at 5 mg/Kg orally twice per day, a significant and rapid reduction in leukemia burden was observed. CPI203 is a useful chemical probe to study the suppression of Myc-dependent cancer development. 

How to Use:

• In vitro:  CPI203 was used at 0.5-1 µM final concentration in various in vitro assays.
• In vivo: CPI203 could be dosed to the mice by oral administration at 5 mg/kg twice per day for 7 days. 

Reference: 

• 1. Devaiah BN, et al. BRD4 is an atypical kinase that phosphorylates serine2 of the RNA polymerase II carboxy-terminal domain. (2012) Proc Natl Acad Sci U S A. 109(18):6927-32.
• 2. Bryan King, et al. The Ubiquitin Ligase Fbxw7 Modulates Leukemia-Initiating Cell Activity by Regulating Myc Stability. (2013) Cell 153(7):1552-66.
• 3. Moros A, et al. Synergistic antitumor activity of lenalidomide with the BET bromodomain inhibitor CPI203 in bortezomib-resistant mantle cell lymphoma. (2014) Leukemia. In press. 

Products are for research use only. Not for human use.