KDM5-C70 is an ethyl ester derivative of KDM5-C49 and functions as an effective, cell-permeable, pan-KDM5 histone demethylase inhibitor. It exhibits an antiproliferative effect in myeloma cells and induces a genome-wide elevation of H3K4me3 levels.

KDM5-C70 (50 μM; 7 days; MM.1S myeloma cells) treatment reduces the level of phosphorylation of retinoblastoma protein (Rb) while leaving the total level of phosphorylated Rb (pRb) unchanged, indicating impairment of cell cycle progression. KDM5-C70 (1 nM-10 μM; 7 days; MM.1S myeloma cells) treatment displays antiproliferative effects after 7 days of treatment at elevated concentrations (estimated 50% reduction of viability/proliferation for KDM5-C70 at ~20 μM). Chromatin immunoprecipitation followed by next-generation sequencing displays an enhanced H3K4me3 level around transcription start sites with KDM5-C70 but little change with GSK467A at 50 μM inhibitor concentrations [1].