Ceritinib Induces Mitochondrial Fragmentation in Thyroid Cancer Cells by Targeting Drp-1.

Mitochondrial dynamics play a crucial role in thyroid cancer progression by regulating apoptosis, metabolism, and oxidative stress. Ceritinib, a tyrosine kinase inhibitor, shows potential anticancer effects; however, its impact on mitochondrial function in thyroid cancer remains obscure. Herein, we aim to investigate the impact of ceritinib on the mitochondrial functionality in TPC-1 thyroid carcinoma cells and the underlying mechanism. Cell viability was assessed with the CCK-8 assay, and the cytotoxicity was determined by evaluation of the lactate dehydrogenase (LDH) release assay. Mitochondrial reactive oxygen species (ROS) were detected by MitoSOX Green staining. Enzyme-linked immunosorbent assay (ELISA) was applied for 8-hydroxydeoxyguanosine (8-OHdG) determination. Real-time PCR was employed for mRNA levels assessment, and western blotting was applied for protein levels. The morphology of mitochondria was evaluated by means of Mitotracker Red CMXRos staining. Ceritinib triggered mitochondrial oxidative stress, evidenced by elevated ROS and 8-OHdG levels, while suppressing manganese superoxide dismutase (Mn-SOD) activity. It also impaired mitochondrial respiration, ATP production, and Complex III activity, leading to dysfunction. Notably, ceritinib promoted mitochondrial fragmentation by enhancing dynamin-related protein 1 (Drp1) translocation to mitochondria, reducing l-OPA1 and increasing S-OPA1 levels, without altering mitofusins 1 and 2 (Mfn-1 and -2) expression. Mechanistically, ceritinib activated the Mitochondrial Calcium Uniporter (MCU)/calpain pathway, increasing MCU, calpain1/2, and calpain activity. Inhibition of MCU by RU360 reversed ceritinib-induced Drp1 mitochondrial translocation, fragmentation, and ATP depletion. Our findings reveal that ceritinib disrupts mitochondrial dynamics via the MCU/calpain/Drp1 axis. This study identifies a previously unreported mechanism for ceritinib in thyroid carcinoma, suggesting a novel therapeutic strategy.