AKT (Ser473) suppression mediates ceritinib cardiotoxicity through autophagic flux impairment and mitochondrial injury.

Ceritinib, an anaplastic lymphoma kinase (ALK) inhibitor, is associated with cardiovascular adverse events, yet the mechanisms remain incompletely understood. Here, we show that ceritinib impairs left ventricular systolic function in mice and induces cardiomyocyte apoptosis, and identify AKT (Ser473) suppression as a key initiating event. Loss of AKT activity is paralleled by reduced phosphorylation of mTOR (Ser2448) and ULK1 (Ser757), consistent with enhanced autophagy initiation. Concurrently, loss of inhibitory GSK3β (Ser9) phosphorylation correlates with impaired lysosomal function, reflected by disrupted cathepsin D maturation and reduced lysosomal acidification. This mismatch between enhanced autophagy initiation and impaired lysosomal clearance impairs autophagic flux despite preserved autophagosome-lysosome fusion, and causes mitochondrial damage, evidenced by reduced TOMM20 and HSP60 expression and membrane potential loss. Transcriptomic and functional analyses identify AKT2 as a particularly vulnerable isoform in this network. Metformin co-treatment preserves cardiac function and attenuates apoptosis. Mechanistically, metformin increases AMPK (Thr172) phosphorylation and reduces TFEB (Ser122) phosphorylation, restores CTSD maturation, and decreases LC3-II accumulation. These protective effects occur without reversing the suppressed AKT (Ser473) or GSK3β (Ser9) phosphorylation. Together, these findings establish that AKT suppression drives ceritinib cardiotoxicity through autophagic flux impairment and mitochondrial injury, and position AMPK-driven, TFEB-associated lysosomal restoration as a mechanism-based cardioprotective strategy independent of AKT recovery.