Three unanswered questions may redefine the fundamental mechanism of ferroptosis

A new perspective article (Stockwell et al.) argues that despite major advances in ferroptosis research, several central mechanistic questions remain unresolved and may determine the future direction of the field.

Published in the open-access journal Ferroptosis and Oxidative Stress, the article revisits the biochemical foundation of ferroptosis and highlights three unanswered questions that challenge current understanding of this iron-dependent form of regulated cell death.

Ferroptosis is characterized by iron-dependent lipid peroxidation and membrane damage. Unlike apoptosis, it is not driven by caspase activation or DNA fragmentation, but instead results from the accumulation of oxidized phospholipids when cellular antioxidant defenses fail. Key protective systems, including glutathione peroxidase 4 (GPX4), ferroptosis suppressor protein-1 (FSP1), and lipid-soluble antioxidants such as vitamin E, normally prevent the uncontrolled propagation of lipid peroxidation.

Although ferroptosis has become an important topic in cancer biology, neurodegeneration, ischemia-reperfusion injury, and immunology, its core molecular mechanism remains incompletely understood.

In the article, the authors organize the field around three fundamental unanswered questions:

1. How does ferroptosis actually kill a cell?

Although lipid peroxidation is recognized as the hallmark of ferroptosis, the precise execution mechanism of cell death remains unclear. The article emphasizes that researchers still do not know how oxidized phospholipids translate into irreversible cellular collapse.

Several competing models are discussed. One proposes that lipid hydroperoxides cluster within membranes, causing membrane thinning, bending, and the formation of nanometer-scale pores. These pores may trigger osmotic imbalance, calcium influx, and eventual plasma membrane rupture. Other evidence suggests that toxic lipid-derived electrophiles damage proteins and cellular structures during ferroptosis. The authors also highlight emerging evidence that ferroptotic damage can spread between neighboring cells in wave-like patterns before membrane rupture occurs.

Together, these findings suggest that ferroptosis may not result from a single molecular “death switch,” but instead from progressive membrane destabilization and biophysical failure.

2. What is ferroptosis doing in normal physiology?

Most ferroptosis research has focused on disease, but the physiological roles of ferroptosis across the human lifespan remain poorly understood.

The article summarizes growing evidence that ferroptosis participates in embryonic development, tissue remodeling, neurogenesis, erythropoiesis, aging, and tumor suppression. During embryogenesis, ferroptotic waves may help sculpt developing limbs and eliminate excess cells. In aging tissues, iron accumulation may increase ferroptosis susceptibility in organs such as the brain and eye, potentially contributing to neurodegenerative disease.

The authors also emphasize ferroptosis as a natural tumor-suppressive mechanism. Key cancer regulators—including p53, fumarate hydratase, and BAP1—can promote ferroptosis through suppression of SLC7A11 and disruption of antioxidant defenses. At the same time, sex hormone-regulated lipid remodeling pathways may contribute to sex-dependent differences in ferroptosis sensitivity.

Despite these findings, the authors argue that researchers still lack a systematic understanding of where, when, and why ferroptosis is physiologically activated in healthy tissues.

3. How does ferroptosis interact with other forms of regulated cell death?

The article further argues that ferroptosis cannot be fully understood in isolation. Instead, it appears deeply interconnected with apoptosis, necroptosis, pyroptosis, and autophagy through shared stress responses, metabolic dependencies, and signaling pathways.

The authors describe extensive overlap between ferroptosis and apoptosis through mitochondrial metabolism, p53 signaling, ER stress, and BCL-2 family proteins. Connections with necroptosis involve shared regulation by cysteine metabolism and HSP90. Ferroptosis may also intersect with pyroptosis through GPX4-dependent regulation of inflammasome activation and gasdermin cleavage. Meanwhile, autophagy-related processes such as ferritinophagy and lipophagy actively sensitize cells to ferroptosis by increasing iron availability and lipid peroxidation.

Rather than functioning as isolated pathways, the authors suggest that regulated cell death modalities may form an interconnected cellular fate network capable of switching between death programs depending on metabolic and environmental conditions.

The perspective concludes that future ferroptosis research should move beyond simply identifying new regulators and instead focus on resolving the fundamental biological logic of the pathway.

Understanding how ferroptosis is executed, how it functions physiologically, and how it integrates with other cell death modalities may be essential for developing more precise therapeutic strategies targeting cancer, neurodegeneration, inflammation, and aging-related diseases.