In Vitro | In vitro activity: CPI203 inhibits BRD4 in vitro and in cells, while does not affect BRD4 kinase activity in vitro. CPI203 exerts a cytostatic effect in all the 9 MCL cell lines analyzed with GI50 ranging from 0.06 to 0.71 μM, with low cytotoxicity in normal PBMCs from healthy donors. Furthermore, lenalidomide and CPI203, by targeting IRF4 and MYC, efficiently activates the cell death program in MCL cells resistant to bortezomib
Kinase Assay: The BRD4 α-screen assay is a proximity-based assay using a tetraacteylated H4 peptide and the isolated bromodomain 1 of human BRD4. IC50 values are calculated using a 10-point serial dilution of BET inhibitor.
Cell Assay: MCL primary cells and cell lines (2 PBMC cultures from healthy donors and 9 MCL cell lines (Granta-519, JVM-2, UPN1, Z-138, JeKo-1, ZBR, JBR, Mino, REC-1 cells)) are incubated as indicated with lenalidomide and/or CPI203. MTT is added for 2-6 additional hours before spectrophotometric measurement. Each measurement is made in triplicate. Values are represented using untreated control cells. The GI50 is calculated as the concentration that produced 50 % growth inhibition. Combination indexes (CIs) are calculated by using the Calcusyn software version 2.0. The interaction between two drugs is considered synergistic when CI<1. |
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