Cellular survival and proliferation hinge upon the ability to adapt to changing nutritional landscapes. Among these nutrients, glutamine stands out as a pivotal amino acid essential for various biosynthetic processes. Glutamine not only supplies carbon and nitrogen for the synthesis of proteins and nucleotides but also supports energy generation and redox balance. Many tumor cells exhibit a phenomenon termed “glutamine addiction,” reflecting their heightened reliance on this amino acid for fueling their rampant proliferation. However, this dependency is not absolute; some cancer cells employ alternative metabolic routes to bypass glutamine scarcity, complicating treatment strategies aimed at exploiting this weakness.

The study, published in Molecular Cell and led by Assistant Professor Alexis Jourdain from Unil’s Department of Immunobiology, advances our understanding of how cancer cells circumvent glutamine addiction. Dr. Miriam Lisci, a postdoctoral researcher in Jourdain’s laboratory, spearheaded research that highlights the indispensable role of carbon-rich metabolites, particularly pyruvate, in sustaining cell division when glutamine is absent. Pyruvate, a key intermediate in cellular metabolism, can enter the tricarboxylic acid (TCA) cycle to replenish biochemical intermediates and maintain energy production, effectively compensating for glutamine shortage.

Central to this metabolic compensation is a mitochondrial enzyme known as pyruvate carboxylase. This enzyme catalyzes the carboxylation of pyruvate to oxaloacetate, a critical anaplerotic reaction replenishing TCA cycle intermediates. Importantly, pyruvate carboxylase requires vitamin B7 (biotin) as a cofactor to execute its function. In the absence of biotin, this enzyme becomes inactive, halting the compensatory metabolic pathway and stalling cellular proliferation. This finding positions vitamin B7 as a “metabolic license,” a necessary molecular determinant enabling pyruvate-driven metabolism that can override glutamine dependence in cancer cells.

Further deepening the complexity of glutamine addiction, the researchers uncovered a hitherto unappreciated role for the FBXW7 gene in this metabolic interplay. FBXW7 is recognized as a tumor suppressor gene, frequently mutated in various cancer types. The study reveals that mutations in FBXW7 lead to a reduction in pyruvate carboxylase levels, impairing the ability of tumor cells to utilize pyruvate efficiently. As a consequence, mutant FBXW7 cells remain locked in a state of glutamine addiction, unable to activate the biotin-dependent metabolic bypass. This gene-nutrient interaction fundamentally reframes how genetic mutations intersect with metabolic adaptability in cancer.

Importantly, the team demonstrated that specific FBXW7 mutations identified in cancer patients directly induce this metabolic vulnerability. This link, established through a combination of metabolomics and proteomics analyses conducted in collaboration with the University’s specialized platforms and international partners, underscores the translational relevance of these findings. Understanding patient-specific genetic backgrounds could guide precision therapies targeting metabolic dependencies unique to tumor genotypes.

These insights offer a compelling explanation for why some therapeutic strategies targeting glutamine metabolism have underperformed in clinical settings. Cancer cells’ capacity to engage alternative metabolic pathways, such as the pyruvate carboxylase-dependent route enabled by biotin, confers resistance to glutamine deprivation. Thus, single-pathway targeting approaches may be insufficient given the metabolic plasticity inherent to tumor cells.

Looking ahead, Prof. Jourdain and his colleagues emphasize the potential for designing innovative treatment regimens that simultaneously target multiple metabolic axes. Such combinatory approaches could exploit the metabolic inflexibility imposed by FBXW7 mutations or vitamin B7 deprivation, potentially overcoming resistance mechanisms. This multi-targeted strategy represents a promising frontier in oncology, aiming to cut off cancer cells’ escape routes by anticipating and blocking adaptive metabolic rewiring.

The broader implications of this research extend beyond cancer, touching on fundamental principles of cellular metabolism and nutrient sensing. The concept of “metabolic licensing” by vitamins like biotin introduces a nuanced understanding of how micronutrients influence enzymatic activity and metabolic pathway choice, with potential relevance in diverse physiological and pathological contexts.

Altogether, this pioneering study not only delineates a critical metabolic dependency shaped by the interplay of nutrient availability and genetic background but also charts a path toward more effective, metabolism-informed cancer therapies. By exposing how pyruvate carboxylase and biotin serve as lynchpins in bypassing glutamine addiction, it opens novel horizons for exploiting metabolic vulnerabilities in tumors notoriously adept at evading treatment.

With these advances, the fight against cancer gains a powerful new tool: deciphering and manipulating the metabolic “licenses” that cancer cells rely on to thrive under nutrient stress. This elegant integration of genetics, metabolism, and enzymology exemplifies the cutting-edge research necessary to unravel and ultimately outmaneuver the complexities of tumor biology.

Subject of Research: Tumor cell metabolism, glutamine addiction, vitamin B7 (biotin), pyruvate carboxylase, FBXW7 gene mutations, metabolic flexibility in cancer

Article Title: Functional nutrient-genetic profiling reveals biotin and FBXW7 are essential to bypass glutamine addiction

News Publication Date: 25-Feb-2026

Web References:

• Molecular Cell DOI: 10.1016/j.molcel.2026.02.002
• Department of Immunobiology, University of Lausanne: https://www.unil.ch/fbm/en/home/menuinst/recherche/ssf/dib.html
• Jourdain Lab: https://www.jourdainlab.org/
• FBM Metabolomics Platform: https://wp.unil.ch/metabolomics/
• FBM Proteomics Platform: https://wp.unil.ch/paf/

Keywords: Cancer metabolism, glutamine addiction, pyruvate carboxylase, vitamin B7, biotin, FBXW7 gene, metabolic flexibility, tumor vulnerabilities, mitochondrial enzymes, metabolic licensing, metabolic pathways, targeted therapies

The therapeutic landscape of innate immunity in cancer has been traditionally dominated by the activation of TLRs and STING, receptors that detect pathogenic molecules and initiate robust immune responses. While promising in theory, these receptors’ agonists have encountered significant clinical hurdles, ranging from systemic toxicity to limited efficacy. Against this backdrop, the recent identification of ALPK1 as a sensor for bacterial ADP-Hep presents an intriguing alternative, potentially circumventing the pitfalls seen with TLR and STING agonists.

In seminal preclinical studies, administration of ADP-Hep to mice has been shown to induce potent proinflammatory chemokines, notably CXCL10 and CCL2, orchestrating a concerted immune assault on tumors. Crucially, this anti-tumor effect depends on the presence of ALPK1 – mice lacking this receptor fail to mount a comparable response. Such findings underscore ALPK1’s vital role in integrating bacterial metabolic cues into host antitumour immunity, an axis previously unexplored in immuno-oncology.

Delving deeper into the receptor’s biology, mouse models bearing a gain-of-function ALPK1 mutation, specifically the T237M variant associated with autoinflammatory states, demonstrated spontaneous rejection of implanted tumors. This observation not only consolidates ALPK1’s function in antitumour immunity but also hints at the receptor’s potential to be pharmacologically modulated in clinically relevant contexts, leveraging inherited or induced receptor polymorphisms for therapeutic gain.

Building upon the natural ligand, researchers have ingeniously synthesized a novel analogue called UDSP-Hep, which surpasses ADP-Hep in potency and selectivity. Unlike its progenitor, UDSP-Hep’s activity discriminates between ALPK1 polymorphisms that correlate with susceptibility to bacteria-induced colitis in different mouse strains. This ability to distinguish receptor variants enhances the prospect of tailoring ALPK1-targeted therapies, optimizing efficacy while minimizing adverse effects tied to genetic background.

Critically, the antitumor potency of UDSP-Hep goes beyond its innate immunostimulatory capacity. When combined with checkpoint inhibitors, which have revolutionized cancer treatment by unleashing T cell responses, UDSP-Hep exhibits synergistic effects leading to amplified tumor control. Mechanistically, this synergy requires the orchestration of CD8+ cytotoxic T cells alongside dendritic cells (DCs) and macrophages, pointing to a complex interplay between innate and adaptive immunity mediated by ALPK1 activation.

The blockade of chemokine pathways, specifically those involving CXCL10 and CCL2, effectively abrogates the benefits conferred by ALPK1 agonism, highlighting that these chemokines form the molecular bridge between receptor activation and immune cell recruitment within the tumor microenvironment. This chemokine-driven immune cell trafficking is vital for mounting an effective antitumour response, exemplifying the multifaceted immunological axis influenced by ALPK1.

At a cellular level, ALPK1 agonists markedly enhance the antigen-presenting functions of dendritic cells, facilitating cross-presentation—the process by which exogenous tumor antigens are presented on MHC class I molecules to prime CD8+ T cells. This function is pivotal for eliciting robust, tumor-specific cytotoxic T lymphocyte expansion in the tumor-draining lymph nodes, thus setting the stage for durable immunological memory and long-lasting tumor surveillance.

Notably, ALPK1 expression extends beyond immune cells and is more broadly distributed in non-immune tissues compared to STING. This broader expression profile accompanies a distinct inflammatory signature upon activation, differentiating ALPK1-mediated responses from classical STING pathways. Importantly, ALPK1 agonism does not induce T cell apoptosis, a detrimental side effect associated with some STING agonists that dampens therapeutic efficacy.

The distinct immunological cascade triggered by UDSP-Hep confers multiple advantages, including enhanced tumor cell antigen presentation, improved macrophage-dendritic cell cross-priming, and promotion of protective memory T cell phenotypes. These immunological hallmarks underline the therapeutic potential of ALPK1 agonists not only as monotherapies but also as critical adjuncts to existing immunotherapeutic modalities.

The discovery and characterization of ALPK1 as a cytosolic receptor mediating bacterial metabolite-induced antitumour immunity herald a paradigm shift in the field. By defining a new immune axis distinct from TLR and STING, this work expands the arsenal for cancer immunotherapists and opens avenues for precision-based interventions tailored to receptor polymorphisms and individual immune landscapes.

Looking ahead, the translation of ALPK1 agonists like UDSP-Hep into clinical settings holds promise for patients resistant to current checkpoint inhibitors or those with tumors refractory to standard immunotherapies. The synergy observed in preclinical models lays a strong foundation, but rigorous clinical trials will be essential to define dosing, safety profiles, and combination strategies to harness this pathway fully.

Moreover, understanding the broader implications of ALPK1 activation in various tissues and its role in inflammatory diseases linked to bacterial sensing could provide insights into balancing immunity and tolerance. Such knowledge is crucial for mitigating potential off-target effects and optimizing the therapeutic window for ALPK1-targeted agents.

In summary, the identification and exploitation of ALPK1 agonists mark a significant milestone in cancer immunotherapy research. Through sophisticated molecular design and insightful immunobiological investigation, this approach promises to augment the cancer treatment arsenal, potentially transforming patient outcomes by activating a previously underappreciated innate immune pathway linked to bacterial metabolite sensing.

Subject of Research: Investigation of ALPK1 receptor agonists in inducing antitumour immunity and enhancing cancer immunotherapy.

Article Title: Agonists for cytosolic bacterial receptor ALPK1 induce antitumour immunity.

Article References:
Tian, X., Liu, J., Li, Y. et al. Agonists for cytosolic bacterial receptor ALPK1 induce antitumour immunity. Nature (2025). https://doi.org/10.1038/s41586-025-09828-9

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41586-025-09828-9

NSCLC remains one of the leading causes of cancer-related mortality worldwide, frequently presenting challenges due to resistance to apoptosis, the most commonly targeted cell death pathway in cancer therapies. The discovery that fosinopril induces pyroptosis, rather than apoptosis, marks a significant paradigm shift. Pyroptosis is a form of lytic programmed cell death characterized by cellular swelling, membrane rupture, and inflammatory cytokine release. This form of cell death, mediated through gasdermin family proteins, offers a promising alternative to eradicate cancer cells that evade apoptosis.

Central to this mechanism is gasdermin E (GSDME), a protein that, when cleaved, forms pores in the plasma membrane, leading to cell swelling and lysis. The study meticulously delineates how fosinopril activates caspase proteins, which in turn cleave GSDME, unleashing its pyroptotic function. This process contrasts significantly with the classical apoptosis pathway, where cells undergo controlled dismantling without eliciting inflammation, underscoring an innovative anti-cancer modality that not only kills the tumor cells but potentially activates an immune response against the tumor microenvironment.

The researchers utilized both in vitro and in vivo NSCLC models to validate fosinopril’s efficacy. At the molecular level, they observed increased expression and cleavage of GSDME following fosinopril treatment, correlating with enhanced pyroptotic markers such as cell swelling and lactate dehydrogenase (LDH) release. These pyroptotic events culminated in a marked reduction of tumor cell viability and tumor burden in animal models, suggesting a potent antitumor effect mechanistically linked to pyroptosis induction.

Further molecular analyses revealed that fosinopril’s induction of pyroptosis is intricately tied to the activation of upstream caspases, particularly caspase-3, known to bridge apoptotic and pyroptotic pathways by cleaving GSDME. This cleavage releases the GSDME N-terminal domain, which oligomerizes within the plasma membrane, generating pores that rupture the cell membrane, expelling intracellular contents and alerting the immune system. The inflammatory milieu engendered by pyroptosis could synergistically enhance anti-cancer immunity, a feature absent in apoptosis-driven therapies.

This study pioneers the repositioning of fosinopril beyond its conventional role as an angiotensin-converting enzyme (ACE) inhibitor. The molecular crosstalk between the renin-angiotensin system and pyroptotic pathways had remained largely unexplored prior to this investigation. By delineating these unexpected interactions, the authors provide a compelling rationale for clinical trials aiming to harness fosinopril’s dual functions, potentially improving NSCLC outcomes while capitalizing on its known safety profile.

The implications of this research extend deep into the clinical realm, where resistance mechanisms often limit the efficacy of targeted therapies and immunotherapies in NSCLC. Leveraging pyroptosis as a therapeutic endpoint offers a novel mode of action that might circumvent existing resistance and potentiate combination therapies. Moreover, the inflammatory aftermath of pyroptosis could enhance tumor antigen presentation and immunogenicity, possibly converting “cold” tumors resistant to immunotherapy into “hot,” more responsive ones.

Crucially, the researchers also addressed possible off-target effects and toxicity, conducting comprehensive assessments across various non-cancerous cell lines. Their data underscored a favorable therapeutic window where fosinopril selectively triggered pyroptosis in tumorigenic cells with minimal cytotoxicity in normal pulmonary tissues. This selectivity hints at mechanistic nuances within cancer cells’ microenvironment or genetic landscape that sensitize them to GSDME-mediated pyroptosis.

Mechanistically, the study delves into the signaling pathways upstream of caspase activation, uncovering involvement of mitochondrial dysfunction and reactive oxygen species (ROS) generation. Fosinopril treatment resulted in mitochondrial membrane potential disruption, elevating intracellular ROS, which serves as a pro-apoptotic and pyroptotic stimulus. These findings highlight a multifactorial process where fosinopril orchestrates a complex interplay of signals culminating in cancer cell death.

While previous studies have implicated pyroptosis in infectious and inflammatory diseases, its therapeutic exploitation in oncology remains nascent. This research serves as a landmark, suggesting that repurposing classical drugs to exploit this pathway can accelerate translational efforts. The authors propose that targeting GSDME expression or function could be customized to individual patient tumors, tailoring treatments based on the tumor’s molecular profile and pyroptotic susceptibility.

The study also explored synergistic potential by combining fosinopril with existing chemotherapeutic agents. Preliminary data indicated enhanced efficacy, possibly through additive or cooperative induction of cell death pathways. This combinatorial approach could mitigate limitations of monotherapy and offer robust therapeutic responses in diverse NSCLC patient populations.

On a broader scale, the ability to induce pyroptosis selectively in tumor cells may herald transformative shifts in cancer immunotherapy. The immunogenic nature of pyroptotic cell demise, characterized by the release of pro-inflammatory cytokines such as IL-1β and IL-18, offers a template for in situ tumor vaccination strategies. Fosinopril may thus serve as a prototype for designing drugs that couple cytotoxicity with immune activation, an intersection critical for durable cancer control.

The researchers also emphasize the need for extensive clinical validation, recognizing that translating these promising preclinical outcomes into effective human therapies will necessitate rigorous pharmacokinetic and pharmacodynamic studies. Variables such as dosage optimization, delivery modalities, and patient stratification based on GSDME expression levels will be pivotal for maximizing therapeutic benefits while minimizing adverse effects.

Moreover, the broader implications for ACE inhibitors in oncology warrant reevaluation, as fosinopril’s anticancer properties could inspire systematic screening of related compounds for pyroptotic activity. This could foster a new class of anti-cancer agents that repurpose existing drugs, thereby shortening development timelines and enhancing patient accessibility.

In conclusion, the study by Gao, Zhai, Zhang, and colleagues represents a quantum leap in lung cancer therapeutics, revealing a previously unrecognized mechanism by which fosinopril exerts antitumor effects via GSDME-dependent pyroptosis. This work not only broadens the mechanistic understanding of cancer cell death but also paves the way for innovative, immune-activating treatment strategies against NSCLC, a cancer subtype in urgent need of novel therapeutic options.

Subject of Research: The investigation focuses on fosinopril’s antitumor effects mediated through the induction of gasdermin E (GSDME)-dependent pyroptosis in non-small cell lung cancer (NSCLC).

Article Title: Fosinopril mediates antitumor efficacy by inducing GSDME-dependent pyroptosis in NSCLC.

Article References:
Gao, Y., Zhai, X., Zhang, C. et al. Fosinopril mediates antitumor efficacy by inducing GSDME-dependent pyroptosis in NSCLC. Cell Death Discov. 11, 540 (2025). https://doi.org/10.1038/s41420-025-02791-4

Image Credits: AI Generated

DOI: 21 November 2025