Table of Contents
- Introduction: Why This Research Matters
- Conventional Wisdom: What Remained Unknown
- New Discoveries: What This Research Revealed
- A Detailed Look at the Molecular Mechanism: Understanding the Cell’s Defense System
- Hopes for Clinical Application: Tackling Cancer, Neurodegenerative Diseases, and Ischemic Disease
- Summary: The Future Brought by Controlling Cell Death
- Paper Information
1. Introduction: Why This Research Matters
Our bodies are made up of tens of trillions of cells. When these cells reach the end of their lifespan or become infected by a pathogen, they carry a built-in mechanism to end their own lives, known as “programmed cell death.” This is like deliberately demolishing an aging building according to a plan in order to preserve the safety and functionality of the entire city. The best-known form of cell death is called “apoptosis,” a highly orderly process in which a cell quietly shrinks and disappears.
In recent years, however, scientists have discovered a form of cell death that is entirely different from apoptosis—one that is more violent and harder to control. This is “ferroptosis.” As its name suggests, ferroptosis means iron-dependent cell death. It is a phenomenon in which iron accumulates excessively inside a cell, triggering the cell membrane to “rust” and rupture. To put it another way, it is like an old water pipe rusting on the inside until, in the end, the entire pipe bursts rather than merely leaking—a catastrophic event.
It has become increasingly clear that this ferroptosis lies at the root of many intractable diseases facing modern medicine, including cancer; neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease; and ischemia-reperfusion injury following myocardial infarction and stroke.
Current treatments, particularly for some neurodegenerative diseases and advanced cancers, can slow the progression of disease but fall short of achieving a fundamental cure. This is because, in these diseases, ferroptosis—the “rusting death of cells”—is a major driver that worsens the pathology. This review paper, “Ferroptosis inhibitors: mechanisms of action and therapeutic potential,” comprehensively summarizes the latest research trends in “ferroptosis inhibitors” designed to halt this rusting death of cells, and it suggests the potential to provide a new means of intervention against these intractable diseases. This research is truly a groundbreaking step that sheds light on pathologies for which existing drugs offer no solution.
2. Conventional Wisdom: What Remained Unknown
Research on cell death has a long history, but for a long time the principal target was “apoptosis.” Apoptosis is a suicide program that a cell carries out voluntarily, and it is strictly controlled by the activation of specific proteins (such as caspases). For this reason, many anticancer agents and therapeutic drugs have been developed to target this apoptotic pathway.
However, mysteries remained regarding cancer cells that can evade apoptosis, as well as the mechanisms of neurodegenerative diseases in which cells die off independently of apoptosis. According to conventional wisdom, the causes of cell death were thought to be mainly either apoptosis or simple “necrosis” due to trauma. This was like thinking that there were only two options for demolishing a building in a city: “planned demolition (apoptosis)” or “collapse due to an accident (necrosis).”
It was only relatively recently that ferroptosis came to be recognized as an independent form of cell death. This discovery revealed that this phenomenon, which could be called a “third form of cell death,” is extremely important in certain pathologies—particularly those involving oxidative stress.
The major questions left unanswered by previous research were the following.
- Through what specific molecular mechanisms is ferroptosis controlled?: It was known that the accumulation of iron acts as the trigger, but the overall picture of the defense system (the antioxidant system) by which cells protect themselves from this “rusting,” and the specific molecular events that cause that system to break down, were not clear.
- What is the method for inhibiting ferroptosis specifically and safely?: Iron is a mineral essential for sustaining life. Simply removing iron would have side effects that are far too great. It was unclear what the “key” molecule would be that could pinpoint the steps specific to ferroptosis among the processes of cell death.
- If treatment-resistant cancer cells are resistant to apoptosis, can this be overcome by inducing ferroptosis?: Many cancer cells acquire resistance to conventional anticancer drugs (the apoptosis-inducing type). If ferroptosis were an entirely different pathway, there was hope that inducing it might break through the wall of treatment resistance, but the specific strategy for doing so had not been established.
These questions were major obstacles to treating intractable diseases. It was as if, even though the enemy’s (the disease’s) weakness (the mechanism of cell death) was known, the precise weapon (the inhibitor) needed to attack it was lacking. This review paper seeks to answer these questions by revealing the full picture of ferroptosis inhibitors as the “precise weapons” currently under development.
3. New Discoveries: What This Research Revealed
This review paper covers the cutting edge of ferroptosis research and clearly shows that the strategies for preventing the “rusting death” of cells consist not of a single pathway but of targeting multiple lines of defense. Its key discoveries and their significance are as follows.
Discovery 1: Ferroptosis inhibitors mainly target three lines of defense
In conventional cell death research, the dominant way of thinking was one inhibitor for one cell death pathway. However, this review systematized the fact that, in order to effectively prevent ferroptosis, strategies are being adopted that intervene from at least three different angles against the “rusting” process that proceeds inside the cell. To use an analogy, this demonstrates the importance of taking a three-pronged set of measures to prevent a fire (cell death): “removing the fuel (iron),” “supplying a fire-extinguishing agent (an antioxidant),” and “directly cooling the source of the fire (lipid peroxidation).”
Discovery 2: Maintaining GPX4 (glutathione peroxidase 4) is the “command center” of the defense system
This review reaffirms the role of GPX4 (Glutathione Peroxidase 4) as the enzyme positioned at the center of the ferroptosis defense system, and it emphasizes that inhibitors which maintain and restore its activity show the most powerful therapeutic effects. GPX4 is like a cell’s “toxic-waste disposal team”: it detoxifies lipids—which are components of the cell membrane—before they are oxidized into toxic lipid peroxides (“rusted fats”), by converting them into water and harmless alcohols. When GPX4 loses its function, the cell tips rapidly toward ferroptosis. This discovery indicates that molecules that stabilize GPX4 (for example, liproxstatin derivatives) are extremely promising candidates for neuroprotection and organ protection.
Discovery 3: Strategies to overcome “ferroptosis resistance” in cancer treatment have been clarified
Many cancer cells fortify their defenses against the oxidative stress induced by treatment, for instance by overexpressing GPX4. In other words, cancer cells are “resistant” to ferroptosis. This review shows that, in order to break through this resistance, a strategy of combining “iron chelators” that cut off the iron supply with drugs that directly inhibit GPX4 function is effective. This suggests the effectiveness of a strategy that, against the impregnable fortress that is a cancer cell, does not merely bombard it (induce apoptosis) but lays a complex siege: cutting off the supply route of its food (iron) through chelation while simultaneously neutralizing its defense system (GPX4).
Discovery 4: Potential as a fast-acting means of intervention for ischemia-reperfusion injury (IRI)
Ferroptosis is deeply involved in the tissue damage (ischemia-reperfusion injury) that occurs when blood flow is temporarily interrupted, as in myocardial infarction or stroke, and is then restored, causing damage through a sudden supply of oxygen. This review shows that ferroptosis inhibitors are highly effective as an “emergency measure” to prevent the sudden cell death immediately after this reperfusion. This is like, just before a flood (reperfusion) occurs, reinforcing the levee (the cell membrane) and putting the drainage pumps (the antioxidant system) into emergency operation. In particular, it is emphasized that iron chelators and lipid peroxidation inhibitors are a field where clinical applications—such as adding them to preservation solutions during organ transplantation—can be expected in the near future.
These discoveries dramatically rewrite the conventional concept of controlling cell death, and they give a clear direction to drug discovery research targeting ferroptosis.
4. A Detailed Look at the Molecular Mechanism: Understanding the Cell’s Defense System
In ferroptosis, the key lies in the excessive accumulation of iron within the cell and the subsequent phenomenon of lipid peroxidation. In this section, let us take a detailed look at how cells reach this “rusting death” and which molecules the inhibitors target.
4.1. Iron Accumulation: The “Fuel” of Ferroptosis
Iron within the cell is normally stored safely inside a storage protein called ferritin. Ferritin is like a “safe” that keeps the cell’s iron locked away. However, if this safe is broken for some reason, or if the uptake of iron becomes excessive, the iron is released into the cytoplasm as highly reactive labile iron (Labile Iron Pool, LIP). This labile iron is an extremely powerful catalyst and triggers a chemical reaction called the Fenton reaction. In the Fenton reaction, reactive oxygen species generated from oxygen molecules react with iron to produce hydroxyl radicals, which are extremely harmful to the cell. This is like iron acting as a catalyst to generate a powerful corrosive acid inside the cell.
The inhibitor’s target (the first line of defense): iron chelators
Iron chelators (for example, deferoxamine, DFO) bind to this labile iron and form a chemically stable complex, rendering it harmless. This plays the role of trapping the iron that rampages inside the cell in a safe capsule.
4.2. Lipid Peroxidation: The “Rusting” of the Cell Membrane
The cell membrane is composed mainly of lipids called polyunsaturated fatty acids (PUFAs). Because of their chemical structure, PUFAs are susceptible to attack by reactive oxygen species and labile iron and are easily oxidized. This oxidation process is lipid peroxidation. When lipids are oxidized, the structure of the cell membrane is destroyed, the cell’s function ceases, and ultimately the cell ruptures.
The inhibitor’s target (the second line of defense): lipid peroxidation inhibitors
One of the molecules responsible for this line of defense is an enzyme called lipoxygenase (LOX). LOX is an enzyme like an “instigator” that actively promotes the oxidation of PUFAs. Drugs that inhibit LOX activity (for example, liproxstatin-1) sever the chain reaction of lipid peroxidation and suppress ferroptosis.
4.3. The GPX4 System: The Cell’s “Toxic-Waste Disposal Team”
Cells are equipped with a powerful antioxidant system to counter this lipid peroxidation. At its center is the aforementioned GPX4 (glutathione peroxidase 4).
GPX4 uses glutathione (GSH), the main antioxidant molecule within the cell, as its “fuel” to reduce harmful lipid peroxides into harmless alcohols. Glutathione is like the cell’s “battery,” and for GPX4 to work, it must always be in a charged state (reduced glutathione).
The protein responsible for supplying this glutathione is a transport protein called the cystine/glutamate antiporter (System Xc-). This transporter takes up cystine from outside the cell and uses it as a raw material for glutathione synthesis. System Xc- is like the cell’s “raw-material loading dock.”
The inhibitor’s target (the third line of defense): GPX4 activators and the control of System Xc-
Drugs that induce ferroptosis (for example, erastin) inhibit the function of this System Xc- and cut off the supply of raw material for glutathione. As a result, GPX4 falls into dysfunction and cell death occurs.
Conversely, drugs that inhibit ferroptosis directly support the function of GPX4 or promote the synthesis of glutathione. One of the most closely watched inhibitors is ferrostatin-1, a derivative of vitamin E. Ferrostatin-1 directly halts the oxidation chain reaction of lipids, thereby lightening the burden on GPX4 and preventing cell death.
By understanding these molecular mechanisms, researchers can devise precise strategies—which line of defense to reinforce according to the pathology, or, as in cancer treatment, which line of defense to deliberately destroy.
5. Hopes for Clinical Application: Tackling Cancer, Neurodegenerative Diseases, and Ischemic Disease
Research on ferroptosis inhibitors is at last moving from the stage of basic science toward the bridge to clinical application. The therapeutic potential that this new class of drugs offers is immeasurable, and expectations are especially high in the following three fields.
5.1. Cancer Treatment: Overcoming Resistance
The greatest challenge in cancer treatment is drug resistance. Many advanced cancers and intractable cancers (for example, pancreatic cancer and triple-negative breast cancer) have “immunity” to apoptosis-inducing anticancer drugs.
The application of ferroptosis to cancer turns this defense system of cancer cells against them. Cancer cells require large amounts of iron for proliferation, and at the same time they make GPX4 work excessively in order to protect themselves from oxidative stress. Researchers are therefore devising a strategy to “induce” ferroptosis.
Specifically, they use System Xc- inhibitors (for example, erastin) and GPX4 inhibitors to collapse the powerful antioxidant system of cancer cells. As a result, the cancer cells can no longer withstand the oxidative stress generated by their own excessive metabolic activity, and they self-destruct through ferroptosis. This approach makes it possible to strike at an entirely new “weakness” in cancer cells against which conventional anticancer drugs are ineffective. Clinical trials suggest that, in certain cancer types, combining existing chemotherapy with ferroptosis-inducing agents may dramatically improve therapeutic efficacy.
5.2. Neurodegenerative Diseases: Protecting Nerve Cells
Neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease develop as specific nerve cells in the brain gradually die off. The abnormal accumulation of iron and oxidative stress are deeply involved in the pathology of these diseases, and ferroptosis is thought to be the principal form of cell death.
In this field, drugs that “inhibit” ferroptosis take the leading role. In particular, the nerve cells present in the brain are extremely vulnerable to oxidative stress. Powerful lipid peroxidation inhibitors such as ferrostatin-1, and iron chelators modified to enter the brain more easily, have been shown in animal models to prevent the rusting of nerve cells and to increase cell survival rates. This holds the potential to extend the lifespan of nerve cells and to slow or even halt the progression of disease. However, breaking through the strict barrier known as the “blood-brain barrier” to deliver drugs efficiently into the brain remains a major challenge on the path to practical use.
5.3. Ischemia-Reperfusion Injury: Organ Protection
It has become clear that ferroptosis is the cause of the tissue damage that occurs during a heart attack or stroke, or during organ transplantation, when blood flow is temporarily interrupted and then restored. This damage hinders the recovery of organ function and worsens prognosis.
In this field, the timing of treatment is extremely important. By administering ferroptosis inhibitors immediately before reperfusion, it is hoped that the sudden rusting of cells can be prevented. For example, during cardiac surgery or kidney transplantation, by adding powerful GPX4 activators or iron chelators to the solution that preserves the organ, it is possible to minimize damage to the organ and improve the engraftment rate after transplantation. This application is seen as highly likely to be introduced into clinical practice within a relatively short period.
5.4. Challenges to Practical Application
Although hopes for clinical application are high, several challenges remain. In particular, improvements in the specificity and pharmacokinetics of the drugs are required. Because ferroptosis is a phenomenon that can occur in cells throughout the body, the drugs must be designed to act specifically on the diseased site (for example, only on cancer cells, or only on specific nerve cells) and not to disturb the iron metabolism or antioxidant systems of normal cells throughout the body. In addition, the development of stable drugs that can be administered orally, and technological development to enhance their transfer into the brain, are urgent priorities.
6. Summary: The Future Brought by Controlling Cell Death
Conventionally, cell death was thought to center on the orderly process of apoptosis, but this review paper reaffirms that the “rusting death” caused by iron-dependent lipid peroxidation—namely, ferroptosis—determines the pathology of many intractable diseases such as cancer, neurodegenerative diseases, and ischemic disease.
The core finding revealed by this research is that “ferroptosis can be precisely controlled by inhibitors that target three main lines of defense: iron chelation, GPX4 activation, and lipid peroxidation inhibition.” This has concretely demonstrated new strategies for breaking through the resistance of cancer cells, as well as groundbreaking means of protecting nerve cells.
Ferroptosis inhibitors are a new means of intervention against pathologies that existing drugs could not address, and they hold the potential to become the foundation for developing novel therapeutic drugs, especially against intractable cancers and neurodegenerative diseases. By improving the specificity and pharmacokinetics of these inhibitors and advancing toward clinical application, future drug discovery research will make a major contribution to human health.
7. Paper Information
Paper title (Japanese):
フェロトーシス阻害剤：作用機序と治療の可能性
Paper title (English):
Ferroptosis inhibitors: mechanisms of action and therapeutic potential.
Authors:
Duo K, Feng X, Tian X, Wang F, Zhao Y, Yu J, Liu Y, He Y, Cai Z.
Journal:
Cellular and Molecular Life Sciences (Cell Mol Life Sci)
Publication information:
(2025)
DOI link:
https://doi.org/10.1007/s00018-025-05958-5
Journal evaluation:
Cell Mol Life Sci is an international academic journal that is highly regarded in the fields of cell biology and molecular medicine. The latest and most important review papers and research results in this field are published in it.