Lipid Peroxidation in Cancer Therapy: Molecular Mechanisms Involving Oxidative Stress, Cell Death, and Therapeutic Response.

Lipid peroxidation (LPO) is a process where polyunsaturated fatty acids (PUFA) in cellular membranes are oxidized. This process is mediated by reactive oxygen species (ROS) and leads to the formation of reactive products, including 4-hydroxynonenal (4-HNE), malondialdehyde (MDA), and oxidized phospholipids. At low concentrations these products act as second messengers in adaptive redox signalling and metabolic homeostasis, whereas at higher concentrations they compromise membrane integrity and promote cell death. Lipid peroxidation plays a crucial role in anticancer therapies. Here we focus on three mechanistically complementary drugs-sorafenib, cisplatin, and olaparib-because each converges, directly or indirectly, on the redox/LPO axis (system xc-/GPX4 modulation, mitochondrial ROS, and SLC7A11 regulation, respectively), modulating tumor cell responses by inducing PUFA oxidation, mitochondrial dysfunction, and membrane damage. However, tumor cells have several protective pathways against oxidative stress, such as increased expression of glutathione peroxidase 4 (GPX4), the SLC7A11 system Xc, and detoxification of reactive aldehydes. Enrichment of membranes with PUFA increases susceptibility to lipid peroxidation and ferroptosis, thereby sensitizing tumor cells to therapy, whereas enrichment with monounsaturated fatty acids (MUFA), driven by the SREBP1-SCD1 axis, limits peroxidation and confers resistance. Among regulated cell death modalities, ferroptosis is strictly dependent on lipid peroxidation, whereas apoptosis, necrosis, necroptosis, pyroptosis, and immunogenic cell death can be modulated by lipid peroxidation but do not universally require it. Collectively, these mechanisms indicate that lipid peroxidation is an important-though not exclusive-determinant of anticancer drug sensitivity and resistance, and that its dual, context-dependent role (tumor-suppressive at high flux, tumor-promoting under chronic, sub-lethal exposure) must be considered when designing LPO-based therapeutic strategies.