Identification of second generation benzylidene chromanone analogues as novel, potent DHODH inhibitors in acute myeloid leukemia cells.

Dihydroorotate dehydrogenase (DHODH) remains as an active target at the preclinical level against acute myeloid leukemia (AML). Herein we report potent second generation benzylidene chromanone (SBL-105) analogues to inhibit DHODH in AML cells. Virtual docking and molecular dynamic simulations were performed. Human-recombinant (rh)DHODH, THP-1, TF-1 and HL-60 cell lines were used. MTT assay was used for cell viability. Flow cytometry was used for differentiation analysis. Computational modeling and simulations predict, SBL-105 analogs bind efficiently to DHODH with improved binding energies. While all tested analogues of SBL-105 inhibited rh DHODH enzyme, SBL-105-4 and SBL-105-6 more effectively inhibited rh DHODH with an IC ₅₀ value of 3.62 and 13.61 nM respectively. SBL-105-4 exhibited excellent anti proliferative effects against THP-1, TF-1 and HL-60 cells with GI ₅₀ values of 18.78, 38.11 and 63.83 nM respectively. A similar effect was also observed in SBL-105-6 treated AML cells with respective GI ₅₀ values of 34.56, 44.40 and 38.65 nM in THP-1, TF-1 and HL-60 cells. An increase in apoptotic populations were enumerated in all three AML cells. Both these compounds also increased the differentiation marker CD11b positive populations in all the three AML cells tested. In conclusion, SBL-105-4 and SBL-105-6 were identified as potent second generation DHODH inhibitors, which drives attention for further preclinical developments.Communicated by Ramaswamy H. Sarma.