ABSTRACT
The paucity of selective agonists for TWIK-related acid-sensitive K+ 3 (TASK-3) channel, a member of two-pore domain K+ (K2P) channels, has contributed to our limited understanding of its biological functions. By targeting a druggable transmembrane cavity using a structure-based drug design approach, we discovered a biguanide compound, CHET3, as a highly selective allosteric activator for TASK-3-containing K2P channels, including TASK-3 homomers and TASK-3/TASK-1 heteromers. CHET3 displayed potent analgesic effects in vivo in a variety of acute and chronic pain models in rodents that could be abolished pharmacologically or by genetic ablation of TASK-3. We further found that TASK-3-containing channels anatomically define a unique population of small-sized, transient receptor potential cation channel subfamily M member 8 (TRPM8)-, transient receptor potential cation channel subfamily V member 1 (TRPV1)-, or tyrosine hydroxylase (TH)-positive nociceptive sensory neurons and functionally regulate their membrane excitability, supporting CHET3 analgesic effects in thermal hyperalgesia and mechanical allodynia under chronic pain. Overall, our proof-of-concept study reveals TASK-3-containing K2P channels as a druggable target for treating pain.
Subject(s)
Analgesics/pharmacology , Ion Channel Gating , Potassium Channels/metabolism , Analgesics/chemistry , Animals , Biguanides/chemistry , Biguanides/pharmacology , Ganglia, Spinal/drug effects , Ganglia, Spinal/metabolism , Ion Channel Gating/drug effects , Ligands , Mice, Knockout , Nociception/drug effects , Potassium Channels/deficiency , Rats , Reproducibility of Results , Sensory Receptor Cells/drug effects , Sensory Receptor Cells/metabolism , Structure-Activity RelationshipABSTRACT
Acute myeloid leukemia is a disorder characterized by abnormal differentiation of myeloid cells and a clonal proliferation derived from primitive hematopoietic stem cells. Interventions that overcome myeloid differentiation have been shown to be a promising therapeutic strategy for acute myeloid leukemia. In this study, we demonstrate that CRISPR/Cas9-mediated knockout of dihydroorotate dehydrogenase leads to apoptosis and normal differentiation of acute myeloid leukemia cells, indicating that dihydroorotate dehydrogenase is a potential differentiation regulator and a therapeutic target in acute myeloid leukemia. By screening a library of natural products, we identified a novel dihydroorotate dehydrogenase inhibitor, isobavachalcone, derived from the traditional Chinese medicine Psoralea corylifolia Using enzymatic analysis, thermal shift assay, pull down, nuclear magnetic resonance, and isothermal titration calorimetry experiments, we demonstrate that isobavachalcone inhibits human dihydroorotate dehydrogenase directly, and triggers apoptosis and differentiation of acute myeloid leukemia cells. Oral administration of isobavachalcone suppresses subcutaneous HL60 xenograft tumor growth without obvious toxicity. Importantly, our results suggest that a combination of isobavachalcone and adriamycin prolonged survival in an intravenous HL60 leukemia model. In summary, this study demonstrates that isobavachalcone triggers apoptosis and differentiation of acute myeloid leukemia cells via pharmacological inhibition of human dihydroorotate dehydrogenase, offering a potential therapeutic strategy for acute myeloid leukemia.
Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Cell Differentiation/drug effects , Enzyme Inhibitors/pharmacology , Oxidoreductases Acting on CH-CH Group Donors/antagonists & inhibitors , Animals , Apoptosis/genetics , Biomarkers, Tumor , Cell Differentiation/genetics , Cell Line, Tumor , Cell Proliferation/drug effects , Chalcones/chemistry , Chalcones/pharmacology , Dihydroorotate Dehydrogenase , Disease Models, Animal , Drug Synergism , Enzyme Activation/drug effects , Gene Expression , Gene Knockdown Techniques , Humans , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/metabolism , Leukemia, Myeloid, Acute/mortality , Mice , Models, Molecular , Molecular Structure , Neoplastic Stem Cells/metabolism , Oxidoreductases Acting on CH-CH Group Donors/genetics , Oxidoreductases Acting on CH-CH Group Donors/metabolism , Prognosis , RNA Interference , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
After cultivation of ginseng, ginsenosides, which are the major active ingredients of gingeng, were approved for use by the food industry, and began to be used as added functional ingredients to try to improve the quality and price of functional foods. However, the interaction between different types of ginsenosides and nutrients needs further study. We investigated the effect of B-complex vitamins (which are essential nutrients) on the pharmacokinetics of the ginsenosides protopanaxatriol-type saponin Rg1, protopanaxadiol-type saponin Rb1, and oleanolic acid-type saponin Ro after oral administration. Ginsenosides Rg1, Rb1, and Ro, with or without B-complex vitamins, respectively, were administered orally to rats to evaluate their pharmacokinetics. The concentration of ginsenosides in plasma was determined by liquid chromatography/tandem mass spectrometry. Pharmacokinetic parameters were fitted using WinNonlin v6.2. After oral coadministration with B-complex vitamins, the area under the concentration-time curve from zero to infinity (AUC0-∞) of ginsenoside Rg1 was reduced by 70%, that of ginsenoside Rb1 was reduced by 43%, and that of ginsenoside Ro was reduced by 34%. The AUC0-∞ of ginsenosides Rg1 and Rb1 showed significant differences between different treatments, but the AUC0-∞ of ginsenoside Ro did not. These results suggest significant ginsenoside-nutrient interactions between ginsenosides Rg1, Rb1, and B-complex vitamins.
