NR2E3 and acute myeloid leukemia: Importantly, the addition of exogenous dNs (including thymidine, deoxyadenosine, deoxyguanosine, and deoxycytidine) as dNTP precursors significantly reversed the cell cycle arrest in S phase caused by MB treatment at a concentration ratio of 2:1 in the AML cells (Figure 3H,I), suggesting that RNR is the active target of the compound in the treated cells, resulting in the inhibition of DNA synthesis and cell proliferation.