RESUMO
Mutations at the arginine residue (R132) in isocitrate dehydrogenase 1 (IDH1) are frequently identified in various human cancers. Inhibition of mutant IDH1 (mIDH1) with small molecules has been clinically validated as a promising therapeutic treatment for acute myeloid leukemia and multiple solid tumors. Herein, we report the discovery and optimization of a series of quinolinones to provide potent and orally bioavailable mIDH1 inhibitors with selectivity over wild-type IDH1. The X-ray structure of an early lead 24 in complex with mIDH1-R132H shows that the inhibitor unexpectedly binds to an allosteric site. Efforts to improve the in vitro and in vivo absorption, distribution, metabolism, and excretion (ADME) properties of 24 yielded a preclinical candidate 63. The detailed preclinical ADME and pharmacology studies of 63 support further development of quinolinone-based mIDH1 inhibitors as therapeutic agents in human trials.
Assuntos
Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Isocitrato Desidrogenase/antagonistas & inibidores , Quinolonas/química , Quinolonas/farmacologia , Sítio Alostérico/efeitos dos fármacos , Animais , Disponibilidade Biológica , Linhagem Celular Tumoral , Cristalografia por Raios X , Cães , Descoberta de Drogas , Inibidores Enzimáticos/farmacocinética , Feminino , Humanos , Isocitrato Desidrogenase/química , Isocitrato Desidrogenase/genética , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Mutação Puntual , Quinolonas/farmacocinéticaRESUMO
Abnormal proliferation mediated by disruption of the normal cell cycle mechanisms is a hallmark of virtually all cancer cells. Compounds targeting complexes between cyclin-dependent kinases (CDK) and cyclins, such as CDK2/cyclin A and CDK2/cyclin E, and inhibiting their kinase activity are regarded as promising antitumor agents to complement the existing therapies. From a high-throughput screening effort, we identified a new class of CDK2/cyclin A/E inhibitors. The hit-to-lead expansion of this class is described. X-ray crystallographic data of early compounds in this series, as well as in vitro testing funneled for rapidly achieving in vivo efficacy, led to a nanomolar inhibitor of CDK2/cyclin A (N-(5-cyclopropyl-1H-pyrazol-3-yl)-2-(2-naphthyl)acetamide (41), PNU-292137, IC50 = 37 nM) with in vivo antitumor activity (TGI > 50%) in a mouse xenograft model at a dose devoid of toxic effects.