In vitro investigation of antineoplastic drug lenvatinib induced cardiotoxicity in terms of molecular mechanisms

Lenvatinib is a multi-tyrosine kinase inhibitor (TKI) approved for the treatment of resistant differentiated thyroid cancer, advanced renal cell carcinoma, anresectable hepatocellular carcinoma, and endometrial carcinoma. Although it is successfull in cancer treatment, it can cause life-threatening side effects such as cardiotoxicity. The molecular mechanism of cardiotoxicity caused by Lenvatinib is not fully known. In this study, the molecular mechanism of Lenvatinib's cardiotoxicity was investigated focusing on mitochondrial toxicity in H9c2 cardiomyocyte cell line. Lenvatinib significantly inhibited cell viability at 48 and 72 hours exposure with three selected concentrations (1.25 μM, 5 μM and 10 μM); and significantly inhibited intracellular ATP at 72 hours. Examined by the flow cytometry method, an increase in the total mass of mitochondria was observed in the 48 hour 10 μM concentration group. Mitochondrial membrane potential was decreased after 48 hours and was recovered after 72 hours treatment. Evaluated with real-time PCR, mitochondrial dynamics (MFN1, MFN2, OPA1, DRP1, FIS1) gene expression levels significantly changed. Lenvatinib triggered the tendency from fusion to fission in mitochondria after 48 hours, and increased both fusion and fission after 72 hours. Apoptosis (ASK1 and JNK) and antioxidant enzyme SOD2 genes increased in the 48 hours 5 μM and 72 hours 10 μM treatment groups. The mtDNA ratio increased after 48 hours and decreased after 72 hours. Mitochondrial changes were detected in the histological evaluation of mitochondria by TEM imaging. Lenvatinib causes cellular stress depending on the concentration and exposure time and affects mitochondrial membrane potential, mitochondrial proteins and ATP synthesis; increases ROS production, and induces mitochondrial damage by disrupting mitochondrial dynamics. The outcome of our study is expected to be a contribution to the understanding of the molecular mechanism of TKI-induced cardiotoxicity, an important side effect frequently encountered during treatment with Lenvatinib and other TKI medications.