CPI-455 is a specific KDM5 inhibitor.

CPI-455 mediates KDM5 inhibition, elevates global levels of H3K4 trimethylation (H3K4me3) and decreases the number of DTPs in multiple cancer cell line models treated with standard chemotherapy or targeted agents[1]. CPI-455 has a high measured affinity for the target KDM5 proteins. Within 24 hours, CPI-455 and CPI-766 can dose-dependently increases in H3K4me3, but not H3K4me2. IC50 calculation for KDM5 Inhibitor CPI-455 in 3 luminal breast cancer cell lines MCF-7, T-47 and EFM-19 are 35.4, 26.19 and 16.13 μM, respectively.

All cell lines were treated with DMSO, CPI-4203 or CPI-455 for 5 d with two changes of medium and drug. Thereafter, the cells (PC9, Colo205, Hs888, M14, SKBR3 and EVSA-T) were plated at 2×105 cells in six-well plates in triplicate and treated for an additional 9-15 d, depending on the cell line model. The Incucyte HD imaging system was used to monitor numbers of drug-tolerant cells after cells were stained with Nuclear-ID Red stain. (Only for Reference)