Synthesis and Profiling of Highly Selective Inhibitors of Methyltransferase DOT1L Based on Carbocyclic C-Nucleosides.

Histone methyltransferase DOT1L is an attractive therapeutic target for the treatment of hematological malignancies. Here, we report the design, synthesis, and profiling of new DOT1L inhibitors based on nonroutine carbocyclic C-nucleoside scaffolds. The experimentally observed SAR was found to be nontrivial as seemingly minor changes of individual substituents resulted in significant changes in the affinity to DOT1L. Molecular modeling suggested that these trends could be related to significant conformational changes of the protein upon interaction with the inhibitors. The compounds and (-)- (), carbocyclic C-nucleoside analogues of the natural nucleoside derivative , and the clinical candidate (pinometostat) potently and selectively inhibit DOT1L in vitro as well as in the cell. The most potent compound was found to be more metabolically stable and significantly less toxic in vivo than pinometostat itself.