DOT1L inhibition blocks multiple myeloma cell proliferation through suppressing IRF4-MYC signaling

Epigenetic alterations play an important role in the pathogenesis in multiple myeloma (MM), but its biological and clinical relevance is not fully understood. Here, we show that DOT1L, which catalyzes methylation of histone H3 lysine 79, is required for the survival of MM cells. Treatment with DOT1L inhibitors induced cell cycle arrest and apoptosis in MM cells, and strongly suppressed cell proliferation in vitro. Chromatin immunoprecipitation-sequencing (ChIP-seq) and microarray analysis revealed that DOT1L inhibition downregulated H3K79 dimethylation (H3K79me2) and expression levels of IRF4-MYC signaling genes in MM cells. Our data suggest that DOT1L may play an essential role in the development of MM, and DOT1L inhibition may provide a new therapy for MM treatment. Gene expression microarray analysis was performed in MM cells treated with SGC0946 for 6 days (RPMI-8226 and MM.1S) or 12 days (KMS-12PE).