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.

Abstract

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 C-terminal heat shock protein 90 inhibitor (KU757) can effectively treat lenvatinib-resistant cells by targeting glycolysis. 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. Extracellular acidification rate demonstrated >2-fold upregulation of glycolysis in lenvatinib-resistant 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-lenvatinib-resistant cells and exosomes and downregulated after KU757 treatment. Lenvatinib resistance leads to increased glycolysis, and KU757 effectively treats lenvatinib-resistant cells and overcomes this increased glycolysis by targeting key glycolytic genes, proteins, and long non-coding ribonucleic acids.