Plitidepsin/Aplidin® resistance is associated with defective cardiolipin remodeling in human cervical cancer cells

Lipid metabolic rewiring is increasingly linked to therapy resistance, yet the contribution of mitochondrial cardiolipins (CL) remains unclear. Because CL support mitochondrial structure, respiration, and regulated cell death, we investigated whether defects in CL metabolism underlie acquired resistance to plitidepsin (Aplidin®, APL) in cervical cancer. Using APL-resistant HeLa cells (APLR), we found pronounced baseline alterations in CL content and acyl composition and a complete failure to remodel CL upon APL exposure. Functionally, APLR cells showed a marked defect in mitochondrial apoptosis, as they failed to induce ROS, lose ΔΨm, activate caspases, or recruit Bid/Bax after treatment. Seahorse analyses revealed reduced basal respiration and no metabolic response to APL, in contrast to the clear respiratory decline observed in WT cells. Lipidomics confirmed that APL triggered coordinated CL remodeling in WT cells—expansion of tetra-acylated CL and accumulation of monolysocardiolipin (MLCL)/dilyso-cardiolipin (DLCL)—whereas APLR cells remained refractory. Correspondingly, APL modulated cardiolipin synthase 1 (CRLS1), phospholipase A2 group VI (PLA2G6, also known as iPLA2), and tafazzin (TAZ) expression only in WT cells. In vivo, APL inhibited WT tumor growth and induced CL remodeling, while APLR xenografts showed neither growth suppression nor lipid remodeling. Overall, these data identify defective CL remodeling as a hallmark of APL resistance and highlight mitochondrial CL metabolism as a potential therapeutic vulnerability.