DHODH inhibition is specific to the pyrimidine synthesis pathway and is rescued by supplemental uridine. (A) Graphs showing intracellular nucleotide concentrations in cells treated with 1 μM BRQ over a time course. Concentrations were normalized to those of untreated controls. Shown are the mean ± standard deviation of 3 replicates. (B) Treatment of Jurkat cells with BRQ showed dose-dependent decreases in cell viability, which is rescued by the addition of supplemental uridine, as measured by CellTiter-Glo. Shown are the mean ± standard deviation of 3 replicates. CTP, cytosine triphosphate; GTP, guanosine triphosphate.