Pyruvate Dehydrogenase Kinase Inhibitors Discovery And Antitumor Studies

Objective: Different kinds of cancer have different genetic signals, a commonfeature of cancer is abnormal metabolic pathway. Such metabolic profile, which ischaracterized by increased aerobic glycolysis and suppressed glucose oxidation,provides cancer cells with a proliferative advantage. Thus, to disrupt metabolicdependencies of cancer cells may represent a selective anticancer strategy. Pyruvatedehydrogenase kinase is the key enzyme that contributes to linking the glycolysismetabolism to the oxidative phosphorylation, which contributes to cancer cellsproliferation, metastasis, migration and apopotosis-resistance. Several clinical studiesreported that PDHK over-expression in cancer was corelated with overall survival ofpatients, radioresistance and prognosis in patients, suggested therapeuticopportunities arising from targeting PDHK in cancer therapy. So far, there are noideal inhibitor of PDHK successfully entered into clinical use.Methods: With the molecular screening platform of PDHK inhibitorsestablished in our lab before, the high throughput screening cellular platform(NCI-H1299) was established via high content analysis, then following screened thecompounds and evaluated the active compounds. As a study revealed that over50%of residues from PDHKs are superimposable with the corresponding residues inHsp90, we adopt the strategy target to ATP binding pocket of PDHK. Then therational design compounds of Hsp90inhibitors were synthesised and screened foridentification the active compounds of PDHK targeted inhibitors and followingstudied the pharmacological effects by which the active compounds affect cancermetabolism and tumor growth.Results: In the primary screening, at molecular level,300rational designedcompounds were screened,43active compounds that could inhibit PDHK1wereidentified via ELISA. We further screened the43compounds at cellular level,5hitswere identified via high content analysis and western blotting. Then we studied theeffects by which the active compounds affect PDHK isoforms, cancer metabolismand tumor growth. At molecular level, MT-ACT-216and Yhhu-3803could inhibit the four isoforms of PDHK at molecular level. At cellular level, MT-ACT-216dramatically inhibited PDH phosphorylation resulted in an increase of oxygenconsumption, ATP and reaction oxygen species (ROS), a decrease of lactate.Yhhu-3803dramatically inhibited PDH phosphorylation resulted in an increase ofreaction oxygen species (ROS). Subsequently, these metabolic alterations induced thedecrease of mitochondrial membrane potential (Δψm) in NCI-H1299cells, and led tothe decrease of cell proliferation.Conclusion: In summary, MT-ACT-216and Yhhu-3803were identified as themost potent candidate compounds on the base of the discovery of PDHK targetedinhibitors established in our lab. Studies on pharmacological effect of MT-ACT-216and Yhhu-3803, indicated that inhibitors of PDHK inhibit the proliferation of cancervia shifting metabolism from glycolysis to glucose oxidation. In conclusion, thesefindings will offer detailed experimental data for further study of the same kind ofcompounds and provide insights into the discovery and development of novel PDHKinhibitors.