Objective

NSD2 (nuclear SET domain&hypen;containing protein 2), a histone lysine methyltransferase, was identified as a potential oncogene through its association with the common IgHt(4;14)(p16; q32) translocation in multiple myeloma (MM). This translocation results in overexpression of NSD2, increased global H3K36Me2 and misregulated gene expression. NSD2 is a large, multi-domain protein and it remains unclear whether its methyltransferase activity is a key driver of tumorigenicity. A biochemical assay using full length NSD2 and Hela Oligonucleosomes showed that the NSD2 mutant Y1179F has a 90% reduction in histone methyltransferase activity. Using CRISPR technology, Y1179F was introduced into all three NSD2 alleles of the MM cell line KMS-11. This resulted in reduced global H3K36Me2 and reduced growth in 3D cultures. Reintroduction of wild type but not catalytically inactive NSD2 fully rescued these defects. Inhibition of biochemical methyltransferase activity was further validated using tool compounds and an IC50 shift with increasing SAM concentration was observed, consistent with the predicted SAM competitive mode of inhibition. Target engagement was confirmed by biophysical studies. Taken together, these data support the importance of NSD2 methyltransferase activity in tumorigenesis and indicate that inhibition of NSD2 methyltransferase activity is a viable drug discovery strategy.