A Combined Chemical, Computational, and In Vitro Approach Identifies SBL-105 as Novel DHODH Inhibitor in Acute Myeloid Leukemia Cells

Inhibition of the dihydroorotate dehydrogenase (DHODH) has been successful at the preclinical level in controlling myeloid leukemia. However, poor clinical trials warrant the search for new potent DHODH inhibitors. Herein we present a novel DHODH inhibitor SBL-105 effective against myeloid leukemia. Chemical characteristics were identified by (1)H NMR, (13)C NMR, and mass spectroscopy. Virtual docking and molecular dynamic simulation analysis were performed using the automated protocol with AutoDock-VINA, GROMACS program. Human-recombinant (rh) DHODH was used for enzyme inhibition study. THP-1, TF-1, HL-60, and SKM-1 cell lines were used. MTT assay was used to assess cell viability. Flow cytometry was employed for cell cycle, apoptosis, and differentiation analysis. Chemical analysis identified the compound to be 3-benzylidene-6,7-benz-chroman-4-one (SBL-105). The compound showed high binding efficacy toward DHODH with a ΔG(binding) score of −10.9 kcal/mol. Trajectory analysis indicated conserved interactions of SBL-105–DHODH to be stable throughout the 200-ns simulation. SBL-105 inhibited rh DHODH with an IC(50) value of 48.48 nM. The GI(50) values of SBL-105 in controlling THP-1, TF-1, HL-60, and SKM-1 cell proliferations were 60.66, 45.33, 73.98, and 86.01 nM, respectively. A dose-dependent increase in S-phase cell cycle arrest and total apoptosis was observed by SBL-105 treatment in both cell types, which were reversed in the presence of uridine. The compound also increased the differentiation marker CD11b-positive populations in both THP-1 and TF-1 cells, which were decreased under uridine influence. SBL-105, a novel DHODH inhibitor, identified using computational and in vitro analysis, was effective in controlling AML cells and needs attention for further preclinical developments.