ABSTRACT
OBJECTIVE To study the role of phosphatidylinositol-3-kinase （PI3K） on sunitinib-induced myocardial systolic dysfunction. METHODS Using human-induced pluripotent stem cell-derived cardiomyocytes （hiPSC-CMS） as objects， the contractile force of cardiomyocytes was measured by CardioExcyte 96 system， and IC50 of sunitinib was calculated after hiPSC- CMS were treated with sunitinib at different concentrations [0 （control）， 0.5， 1， 3， 5， 10 μmol/L] for 24 hours. The effects of sunitinib （3.14 μmol/L） on the contractile frequency of cardiomyocytes， calcium transient amplitude and calcium transient recovery time course， mRNA expression of myocardial injury markers atrial natriuretic peptide （ANP）， brain natriuretic peptide （BNP） and β-myosin heavy chain （β-MHC） were detected. PI3K activator 3，4，5-triphosphate phos-phatidylinositol （PIP3， 1 μmol/L） and sunitinib were used to intervene in hiPSC-CMs jointly， so as to investigate the role of PI3K in the myocardial systolic dysfunction induced by sunitinib. RESULTS Sunitinib inhibited the contractile force of hiPSC-CMs in a concentration-dependent manner. IC50 of sunitinib was 3.14 μmol/L. After intervention with 3.14 μmol/L sunitinib， the contractile frequency of hiPSC-CMs and calcium transient amplitude were decreased significantly （P＜0.05 or P＜0.01）； the duration of calcium transient recovery was prolonged significantly （P＜0.05）， and mRNA expressions of ANP， BNP and β-MHC were significantly increased （P＜0.01）. After PI3K was activated with PIP3， the contractile force of hiPSC-CMs was increased significantly （P＜0.01）. CONCLUSIONS Activating PI3K activity is a potential molecular mechanism to improve myocardial toxicity induced by sunitinib.