A Novel Heat Shock Protein Inhibitor Ku757 With Efficacy In Lenvatinib-Resistant Follicular Thyroid Cancer Cells Overcomes Up-Regulated Glycolysis In Drug-Resistant Cells In Vitro

Background: Patients with advanced differentiated thyroid cancer develop resistance to lenvatinib treatment from metabolic dysregulation. Heat shock protein 90 is a molecular chaperone that plays an important role in glycolysis and metabolic pathway regulation. We hypothesize that lenvatinib-resistant differentiated thyroid cancer cells will have an increased dependency on glycolysis and that a novel Cterminal heat shock protein 90 inhibitor (KU757) can effectively treat lenvatinib-resistant cells by targeting glycolysis.Methods: Inhibitory concentration 50 values of thyroid cancer cells were determined by CellTiter-Glo assay (Promega Corp, Madison, WI). Glycolysis was measured through Seahorse experiments. Reverse transcription-polymerase chain reaction and Western blot evaluated glycolytic pathway genes/proteins. Exosomes were isolated/validated by nanoparticle tracking analysis and Western blot. Differentially expressed long non-coding ribonucleic acids in exosomes and cells were evaluated using quantitative polymerase chain reaction.Results: Extracellular acidification rate demonstrated >2-fold upregulation of glycolysis in lenvatinibresistant cells versus parent cells and was downregulated after KU757 treatment. Lenvatinib-resistant cells showed increased expression of the glycolytic genes lactic acid dehydrogenase, pyruvate kinase M1/2, and hexokinase 2. KU757 treatment resulted in downregulation of these genes and proteins. Several long non-coding ribonucleic acids associated with glycolysis were significantly upregulated in WRO-lenvatiniberesistant cells and exosomes and downregulated after KU757 treatment.Conclusion: Lenvatinib resistance leads to increased glycolysis, and KU757 effectively treats lenvatinibresistant cells and overcomes this increased glycolysis by targeting key glycolytic genes, proteins, and long non-coding ribonucleic acids. (C) 2020 Elsevier Inc. All rights reserved.