Potent synergy of DHODH and SREBP inhibition in acute myeloid leukemia via disruption of cholesterol and lipid metabolism.

Acute myeloid leukemia (AML) remains difficult to cure, in part related to strong genetic and functional heterogeneity between and within individual patients. Metabolic reprogramming is emerging as an important feature of AML cells, allowing exploration of alternative treatment strategies. Here, we describe a novel DHODH inhibitor, JNJ-74856665, that showed strong efficacy in a subset of AML samples. In a multi-omics approach, by combining label-free quantitative proteome data with drug sensitivity data in bone marrow stromal co-cultures in a large cohort of primary AML patient samples we identified that sensitivity to DHODH inhibition (DHODHi) is linked to cholesterol and lipid metabolism. DHODHi resulted in an accumulation of cholesterol, mitochondrial reactive oxygen species (ROS) and lipid peroxidation. LC-MS/ MS-based lipidomics studies revealed that DHODHi resulted in a strong increase in polyunsaturated fatty acids and triglycerides, which are the primary lipid species stored in lipid droplets (LD). We hypothesized that this might be the consequence of increased ROS and lipid peroxidation levels, prompting the cell to detoxify such toxic lipid species by storing them in LD. Indeed, we could observe a marked increase in LD formation upon DHODHi. The transcriptional regulator SREBF2, known to control cholesterol and lipid metabolism, was up-regulated in DHODHi sensitive AML, and a strong synergy was observed between the combination of both DHODHi and the SREBP inhibitor dipyridamole. Our data indicate that it would be interesting to further explore combined DHODH and SREBP inhibition as a therapeutic target option in AML.