Aims: Unique in the broader category of drug-resistant cells, persister cancer cells (PSs) acquire their tolerance to compounds through reversible, chromatin-mediated changes, allowing them to ‘persist’ in the face of cancer therapeutic agents. PSs are implicated in minimal residual disease from which cancer relapse occurs, and given their established sensitivity to ferroptosis, PSs present a critical point through which identification and targeting of drug-resistant cancers may be possible. Ferroptosis sensitivity in drug-resistant cancers may be caused by the attainment of the persister state, or it may merely be correlative with this state and due instead to extended inhibition of oncogenic signaling or the induction of chemotherapy stress. Nonetheless, ferroptosis sensitivity has emerged as a common phenotype across multiple PS and drug-resistant cancer cell types. Identifying biomarkers for and drivers of ferroptosis sensitivity in drug-resistant and PS cells is therefore a high priority.

Methods: We derived PS cells from the lung carcinoma cell line PC9 (PS^PC9), performed transcriptomic analysis, and subsequently lipidomics on the PC9/PS^PC9 system. Additionally, we reverted PS^PC9 cells to the ferroptosis-resistant parental state (PC9^{PS -> PC9}) and assessed the resulting lipid changes. We generated two additional PS-like cell models: PS-like prostate carcinoma (PS^LNCaP) from LNCaP cells and PS-like fibrosarcoma (PS^HT1080) from HT1080 cells, with lipidomics analysis. Finally, we performed a mitochondrial elimination assay and assessed its effect on ferroptosis sensitivity.

Results: We observed enrichment of lipid and sugar metabolism gene expression in PS^PC9; lipidomics revealed enrichment within PS^PC9 for ferroptosis-driving diPUFA phospholipids (diPUFA-PL), as well as polyunsaturated free fatty acids (PUFA FFAs). Upon PS^PC9 reversion to the ferroptosis-resistant parental state (PC9^{PS -> PC9}), this lipid signature reverted. The LNCaP and HT1080 PS-like models individually showed features consistent with PS, including an increased labile-iron pool, reversibility, and enhanced ferroptosis sensitivity, and had lipid features consistent with those in PS^PC9. Finally, mitochondrial elimination partially abrogated ferroptosis sensitivity and altered the PS lipid profile.

Conclusion: In summary, lipidomic changes dependent on the presence of mitochondria are key to the ferroptosis sensitivity of drug-tolerant persister cancer cells.

Ferroptosis is, in many ways, the odd one out among cell death modalities. It does not, at least as far as we know, require an activating signal. Instead, it represents a default cellular fate that is continuously repressed by a multilayered network of surveillance systems. At its core, ferroptosis is driven by the unchecked peroxidation of polyunsaturated phospholipids (PUFA-PLs), a vulnerability shaped by lipid bilayer composition. Glutathione peroxidase 4 (GPX4) is a central defense enzyme that reduces lipid hydroperoxides to their corresponding alcohols using glutathione as a cofactor. This is complemented by ferroptosis suppressor protein-1 (FSP1)-mediated regeneration of coenzyme Q₁₀ or vitamin K at the plasma membrane and reinforced by dietary or endogenous radical-trapping antioxidants, such as vitamin E, squalene, and 7-dehydrocholesterol. Still, ferroptosis sensitivity is not just a function of antioxidant failure but also a direct consequence of the architecture of the membrane itself: the abundance of PUFA-PLs, shaped by acyl-CoA synthetases like ACSL4 and others; the relative scarcity or abundance of monounsaturated fatty acids, which confer resistance; the regulation of membrane repair and remodeling enzymes; and the delicate balance of redox-active iron within organelles such as lysosomes. Together, these elements converge to determine whether ferroptosis remains a manageable threat or becomes lethal. Despite growing mechanistic insights, fundamental riddles endure: Why does ferroptosis exist at all? What is the precise role of iron: catalyst, signal, or inherent peril? Where, within the cell or organism, does ferroptosis ignite? Can we safely harness this pathway for clinical benefit? And ultimately, is ferroptosis truly a form of regulated cell death, or the mere emergence of a primordial biochemical vulnerability? Inspired by Douglas Green’s iconic riddle framework, this review distils five unresolved questions that may define the coming decade of ferroptosis research. Rather than solving them, we aim to refine their silhouettes at the intersection of lipid (bio)chemistry, evolutionary biology, and translational opportunity.

Ferroptosis, an iron-dependent form of regulated cell death (RCD) driven by lipid peroxidation, has been extensively studied since its conceptualization in 2012 and has been suggested as a therapeutic target in many cancers and degenerative diseases. However, three fundamental questions remain unanswered about ferroptosis. First, the mechanisms by which cells execute death during ferroptosis remain elusive: The key role of lipid peroxides in triggering ferroptosis is established, but how this results in the death of a cell remains unclear. Second, the physiological role of ferroptosis throughout the human life cycle is unclear; currently, there is evidence for ferroptosis in early development, immunity, aging, and tumor suppression, but not in many other aspects of physiology. Third, and finally, the intersection between ferroptosis and other RCD modalities, such as apoptosis, necroptosis, pyroptosis, and autophagic cell death, is necessary for understanding how ferroptosis integrates into networks controlling cellular fate. Addressing these gaps in knowledge is essential for building a comprehensive understanding of this mode of cell death, as well as translating ferroptosis knowledge into effective therapeutics.

Disulfidptosis is a recently identified form of regulated cell death (RCD) triggered by disulfide stress when cystine uptake via solute carrier family 7 member 1 (SLC7A11) overwhelms the cell’s reducing capacity. Unlike apoptosis or other “cell suicide” pathways, disulfidptosis likely represents a “cell sabotage” mechanism, defined by aberrant disulfide bonding and catastrophic actin cytoskeleton collapse. In this Perspective, we examine the paradoxical role of SLC7A11 as both a ferroptosis protector and a disulfidptosis trigger, and the mechanistic hallmarks of disulfidptosis. We highlight emerging therapeutic strategies to target disulfidptosis in cancer, including glucose transporter inhibition, redox-targeting agents, and nanomaterial-based approaches, and consider its dual role in immunity, where it may suppress T cell function yet act as a form of immunogenic cell death. Together, these insights position disulfidptosis as both a conceptual advance in RCD biology and a promising target for cancer therapy that warrants further mechanistic and translational exploration.

Ferroptosis is, in many ways, the odd one out among cell death modalities. It does not, at least as far as we know, require an activating signal. Instead, it represents a default cellular fate that is continuously repressed by a multilayered network of surveillance systems. At its core, ferroptosis is driven by the unchecked peroxidation of polyunsaturated phospholipids (PUFA-PLs), a vulnerability shaped by lipid bilayer composition. Glutathione peroxidase 4 (GPX4) is a central defense enzyme that reduces lipid hydroperoxides to their corresponding alcohols using glutathione as a cofactor. This is complemented by ferroptosis suppressor protein-1 (FSP1)-mediated regeneration of coenzyme Q₁₀ or vitamin K at the plasma membrane and reinforced by dietary or endogenous radical-trapping antioxidants, such as vitamin E, squalene, and 7-dehydrocholesterol. Still, ferroptosis sensitivity is not just a function of antioxidant failure but also a direct consequence of the architecture of the membrane itself: the abundance of PUFA-PLs, shaped by acyl-CoA synthetases like ACSL4 and others; the relative scarcity or abundance of monounsaturated fatty acids, which confer resistance; the regulation of membrane repair and remodeling enzymes; and the delicate balance of redox-active iron within organelles such as lysosomes. Together, these elements converge to determine whether ferroptosis remains a manageable threat or becomes lethal. Despite growing mechanistic insights, fundamental riddles endure: Why does ferroptosis exist at all? What is the precise role of iron: catalyst, signal, or inherent peril? Where, within the cell or organism, does ferroptosis ignite? Can we safely harness this pathway for clinical benefit? And ultimately, is ferroptosis truly a form of regulated cell death, or the mere emergence of a primordial biochemical vulnerability? Inspired by Douglas Green’s iconic riddle framework, this review distils five unresolved questions that may define the coming decade of ferroptosis research. Rather than solving them, we aim to refine their silhouettes at the intersection of lipid (bio)chemistry, evolutionary biology, and translational opportunity.

Ferroptosis, an iron-dependent form of regulated cell death (RCD) driven by lipid peroxidation, has been extensively studied since its conceptualization in 2012 and has been suggested as a therapeutic target in many cancers and degenerative diseases. However, three fundamental questions remain unanswered about ferroptosis. First, the mechanisms by which cells execute death during ferroptosis remain elusive: The key role of lipid peroxides in triggering ferroptosis is established, but how this results in the death of a cell remains unclear. Second, the physiological role of ferroptosis throughout the human life cycle is unclear; currently, there is evidence for ferroptosis in early development, immunity, aging, and tumor suppression, but not in many other aspects of physiology. Third, and finally, the intersection between ferroptosis and other RCD modalities, such as apoptosis, necroptosis, pyroptosis, and autophagic cell death, is necessary for understanding how ferroptosis integrates into networks controlling cellular fate. Addressing these gaps in knowledge is essential for building a comprehensive understanding of this mode of cell death, as well as translating ferroptosis knowledge into effective therapeutics.

Aims: Unique in the broader category of drug-resistant cells, persister cancer cells (PSs) acquire their tolerance to compounds through reversible, chromatin-mediated changes, allowing them to ‘persist’ in the face of cancer therapeutic agents. PSs are implicated in minimal residual disease from which cancer relapse occurs, and given their established sensitivity to ferroptosis, PSs present a critical point through which identification and targeting of drug-resistant cancers may be possible. Ferroptosis sensitivity in drug-resistant cancers may be caused by the attainment of the persister state, or it may merely be correlative with this state and due instead to extended inhibition of oncogenic signaling or the induction of chemotherapy stress. Nonetheless, ferroptosis sensitivity has emerged as a common phenotype across multiple PS and drug-resistant cancer cell types. Identifying biomarkers for and drivers of ferroptosis sensitivity in drug-resistant and PS cells is therefore a high priority.

Methods: We derived PS cells from the lung carcinoma cell line PC9 (PS^PC9), performed transcriptomic analysis, and subsequently lipidomics on the PC9/PS^PC9 system. Additionally, we reverted PS^PC9 cells to the ferroptosis-resistant parental state (PC9^{PS -> PC9}) and assessed the resulting lipid changes. We generated two additional PS-like cell models: PS-like prostate carcinoma (PS^LNCaP) from LNCaP cells and PS-like fibrosarcoma (PS^HT1080) from HT1080 cells, with lipidomics analysis. Finally, we performed a mitochondrial elimination assay and assessed its effect on ferroptosis sensitivity.

Results: We observed enrichment of lipid and sugar metabolism gene expression in PS^PC9; lipidomics revealed enrichment within PS^PC9 for ferroptosis-driving diPUFA phospholipids (diPUFA-PL), as well as polyunsaturated free fatty acids (PUFA FFAs). Upon PS^PC9 reversion to the ferroptosis-resistant parental state (PC9^{PS -> PC9}), this lipid signature reverted. The LNCaP and HT1080 PS-like models individually showed features consistent with PS, including an increased labile-iron pool, reversibility, and enhanced ferroptosis sensitivity, and had lipid features consistent with those in PS^PC9. Finally, mitochondrial elimination partially abrogated ferroptosis sensitivity and altered the PS lipid profile.

Conclusion: In summary, lipidomic changes dependent on the presence of mitochondria are key to the ferroptosis sensitivity of drug-tolerant persister cancer cells.

Disulfidptosis is a recently identified form of regulated cell death (RCD) triggered by disulfide stress when cystine uptake via solute carrier family 7 member 1 (SLC7A11) overwhelms the cell’s reducing capacity. Unlike apoptosis or other “cell suicide” pathways, disulfidptosis likely represents a “cell sabotage” mechanism, defined by aberrant disulfide bonding and catastrophic actin cytoskeleton collapse. In this Perspective, we examine the paradoxical role of SLC7A11 as both a ferroptosis protector and a disulfidptosis trigger, and the mechanistic hallmarks of disulfidptosis. We highlight emerging therapeutic strategies to target disulfidptosis in cancer, including glucose transporter inhibition, redox-targeting agents, and nanomaterial-based approaches, and consider its dual role in immunity, where it may suppress T cell function yet act as a form of immunogenic cell death. Together, these insights position disulfidptosis as both a conceptual advance in RCD biology and a promising target for cancer therapy that warrants further mechanistic and translational exploration.