Bifunctional Naphtho[2,3-][1,2,3]triazole-4,9-dione Compounds Exhibit Antitumor Effects In Vitro and In Vivo by Inhibiting Dihydroorotate Dehydrogenase and Inducing Reactive Oxygen Species Production

Human dihydroorotate dehydrogenase (DHODH) is an attractive target for cancer therapy. Based on its crystal structure, we designed and synthesized a focused compound library containing the structural moiety of 1,4-benzoquinone, which possesses reactive oxygen species (ROS) induction capacity. Compound with a naphtho[2,3-][1,2,3]triazole-4,9-dione scaffold exhibited inhibitory activity against DHODH. Further optimization led to compounds and , which inhibited DHODH activity with IC values of 9 and 4.5 nM, respectively. Protein-ligand cocrystal structures clearly depicted hydrogen bond and hydrophobic interactions of and with DHODH. Compounds and significantly inhibited leukemia cell and solid tumor cell proliferation and induced ROS production, mitochondrial dysfunction, apoptosis, and cell cycle arrest. Nanocrystallization of compound displayed significant in vivo antitumor effects in the Raji xenograft model. Overall, this study provides a novel bifunctional compound with DHODH inhibition and ROS induction efficacy, which represents a promising anticancer lead worthy of further exploration.