Exploiting a New Weakness in 'Zombie-Like' Senescent Cells to Treat Cancer and Age-Associated Diseases
核心洞察
Researchers from MRC LMS and Imperial College London identified covalent compounds that selectively kill senescent cells by targeting the GPX4 (搜索) protein, a key ferroptosis defense mechanism.
Screening of 10,000 covalent compounds yielded four promising senolytic candidates, three of which inhibit GPX4 (搜索), removing senescent cells' shield against iron-driven ferroptotic cell death.
In three mouse cancer models, the GPX4 (搜索)-targeting drugs reduced tumor size and improved survival, suggesting potential to complement chemotherapy and immunotherapy.
A new class of drugs that exploits a recently uncovered vulnerability in senescent cells—often called "zombie cells"—could open the door to novel treatments for cancer and age-associated diseases, according to research from the MRC Laboratory of Medical Sciences (搜索) (LMS) and Imperial College London. The study, published in Nature Cell Biology, demonstrates that senescent cells survive on a knife-edge: they accumulate high levels of iron and other ferroptosis-promoting agents but compensate by overproducing the protective protein GPX4 (搜索). Targeting this defense mechanism strips away their shield, triggering fatal ferroptosis.
Senescent cells are a paradoxical presence in tumors. While they do not divide and therefore do not directly enlarge a tumor, they secrete factors that fuel proliferation, metastasis, and detrimental immune activity in neighboring cells. Chemotherapy, which aims to halt rapid cancer cell division, often increases the proportion of senescent cells within a tumor, compounding the problem over time.
"Senescence was considered for a long time to be positive, because senescent cells don't proliferate, which is the core feature of cancer," said Mariantonietta D'Ambrosio, a postdoctoral researcher at the LMS and lead author of the study. "Normal chemotherapy induces senescence blocking the proliferation of cancer cells, so the tumor doesn't get bigger. But with time you also see the negative side of the senescent cells, because they secrete a lot of factors that influence neighbouring cells and induce even more proliferation, metastasis, and recruitment of bad parts of the immune system that will provoke even more aggressiveness in the tumor. For this reason, we tried to find some drugs that were able to kill the senescent cells."
A broad screen narrows to GPX4 (搜索)
Together with collaborators at Imperial's Department of Medicinal Chemistry, the research team cast a wide net, screening 10,000 covalent compounds—molecules capable of forming covalent bonds with their targets and inhibiting proteins previously considered undruggable—against both senescent and normal cells. They sought compounds that preferentially killed senescent cells, classifying such drugs as "senolytics."
The screen narrowed to just four promising compounds. Three of them converged on a single protein target: GPX4 (搜索). This protein plays a critical protective role in cells by preventing ferroptosis, a form of cell death driven by high iron levels and destructive reactive oxygen species. Ferroptosis had only recently been identified as a potential Achilles' heel of senescent cells.
"Recent papers have shown this predisposition of senescent cells to ferroptosis, but it's a new senescence vulnerability. That creates an opportunity for us to exploit. So now there is research to find senolytic drugs to kill cells through ferroptosis," D'Ambrosio explained.
Senescent cells, it turns out, maintain elevated GPX4 (搜索) levels to counteract their own high iron burden. The analogy is akin to taking a painkiller to keep running on an injured ankle: the underlying damage persists, but the immediate consequences are masked. Blocking GPX4 activity—as the identified compounds do—removes that protection, making ferroptosis unavoidable.
Efficacy across three cancer models
The team evaluated their GPX4 (搜索)-targeting drugs in three distinct mouse models of cancer. In each case, senescent cell death translated into measurable therapeutic benefit: reduced tumor size and improved survival. Translating these findings to patients could significantly augment existing cancer treatment paradigms.
"In mouse models we saw that these drugs reduced tumor size, and improved survival. Now we need to see the effect on the immune system. Is the improvement also awakening the 'good side' of the immune system—T cells, natural killer cells—that helps to kill the tumor?" said Professor Jesus Gil, senior author and Head of the Senescence group at the LMS. "Once we know more, the next step is to understand which cancer cell types or specific patients might better respond to this treatment. For example, if a patient undergoing chemotherapy overexpressed GPX4 (搜索) then you could use this approach in combination with existing drugs to improve efficacy."
D'Ambrosio underscored the broader potential: "Targeting senescence is a huge opportunity for cancer treatments, and ultimately it can play a supporting role in addition to chemotherapy and immunotherapy."
A cautionary note: not all senescence is permanent
While the LMS-Imperial findings highlight the therapeutic promise of senolytics, a separate study from IDIBELL (搜索) and the Catalan Institute of Oncology (搜索) (ICO), published in Cell Death & Disease, offers an important caveat. Researchers led by Dr. Cristina Muñoz Pinedo and Dr. Ernest Nadal investigated the effects of the senescence-inducing drug palbociclib—already used clinically in breast cancer—on pleural mesothelioma (搜索), a rare and aggressive asbestos-linked lung tumor.
Their results were unexpected. Although treated mesothelioma cells displayed the visual and biochemical hallmarks of senescence, the state was not complete. The cells entered what the team termed "pseudosenescence": upon drug withdrawal, they regained proliferative capacity and proved resistant to senolytics.
"Although all tumour cells had the visual and biochemical features of senescence after treatment, senescence was not complete," said Dr. Nadal, also scientific director of ICO. "This suggests that, in therapies like this, cells may appear senescent and unproliferative, essentially half dead, but in reality they can grow back, so it is necessary to deliver a 'second blow' to ensure that tumour cells die."
Iswarya Sreeram, first author of the IDIBELL (搜索) study, noted that senescence is "a spectrum of stability that depends on the drug used to induce it and the type of tumour. That means we can't rely entirely on molecular markers to identify a senescent state in treated tumour cells, but it's vital to make sure they can't regain their proliferative capacity."
The IDIBELL (搜索) findings reinforce that senescence is not a uniform biological state, underscoring the importance of verifying irreversible proliferative arrest when designing senescence-based therapeutic strategies—and highlighting why the GPX4 (搜索)-targeting approach from the LMS team, which directly kills senescent cells rather than merely inducing senescence, may hold particular clinical value.
Researchers from the Institute of Oncology Research (IOR) in Bellinzona, Switzerland and the M3 Research Centre at the University of Tübingen in Germany also contributed to the LMS-Imperial study.