Guido Kroemer

NUAK1 and AMPK control lipid metabolism, mitochondrial dynamics, and myosin-dependent cell migration in mesenchymal colon cancer cells

A consensus molecular subtype classification has identified four groups (CMS1-4) in colon cancer (CC), with CMS4 associated with the poorest prognosis, largely due to its high metastatic potential. Although the cellular and molecular features of CMS4 tumors have been increasingly characterized, the signaling networks that sustain their mesenchymal and invasive phenotype remain incompletely understood. Here, using the prototypical CMS4 MDST8 cell line under adherent and non-adherent conditions, we investigated the interplay between actomyosin contractility, lipid metabolism, and mitochondrial dynamics. We found that adherent MDST8 cells exhibited a low pAMPK/AMPK ratio, associated with reduced fatty-acid oxidation (FAO), enhanced lipogenesis, and a highly interconnected mitochondrial network. Loss of adherence was accompanied by activation of the NUAK1 (an AMPK-related kinase)-MLC2 (myosin light chain 2) phosphorylation cascade, which was independent of AMPK. Notably, both AMPK and NUAK1, two members of the same kinase family, were activated by LKB1 following cell detachment. Unexpectedly, non-adherent MDST8 cells simultaneously activated FAO and fatty-acid synthesis, two pathways generally considered antagonistic. Detachment from the culture support also induced mitochondrial fission, likely driven by DRP1 phosphorylation at Ser 616 , and we propose that this remodeling of mitochondrial architecture may underlie the concomitant activation of FAO and lipogenesis. Furthermore, we demonstrated that siRNA-mediated knockdown or pharmacological inhibition of DRP1, NUAK1, or AMPK impaired MDST8 cell migration and invasion, underscoring the functional relevance of the signaling cascade activated upon cellular detachment. Finally, analysis of a CC patient cohort revealed that expression of key components of this pathway correlates with clinical outcome, suggesting potential prognostic value. Altogether, our findings uncover a coordinated signaling network linking contractility, lipid metabolism, and mitochondrial dynamics in CMS4 colon cancer cells, and identify actionable molecular targets that may help limit mesenchymal cell dissemination and metastasis.

Time-domain NMR enables non-invasive longitudinal monitoring of intrahepatic cholangiocarcinoma in mice

Intrahepatic cholangiocarcinoma (iCCA) is an aggressive biliary malignancy for which longitudinal non-invasive monitoring remains challenging in preclinical models. Using time-domain nuclear magnetic resonance (TD-NMR), we characterized disease-associated whole-body composition changes in the pNICD/pAKT hydrodynamic injection mouse model of iCCA. Tumor-bearing mice developed a progressive increase in whole-body fluid relative to body weight and a decrease in fat mass relative to body weight compared with tumor-free controls, despite stable total body weight. Ultrasound confirmed the presence of cystic hepatic lesions but was used as a qualitative structural assessment rather than a serial quantitative comparator. Day-specific receiver operating characteristic analyses showed that fluid/weight and fat mass/weight ratios increasingly discriminated iCCA-bearing from tumor-free mice as disease progressed. Exploratory within-animal analyses further showed that absolute body-composition ratios, particularly fluid/weight ratio, distinguished terminal clinical assessments from predefined earlier assessments. Daily relative changes in normalized parameters showed more variable performance and did not improve classification of terminal clinical status. These findings identify TD-NMR-derived fluid and fat ratios as practical longitudinal markers of physiological changes associated with iCCA progression in this model. Direct quantification of ascites and prospective validation in independent cohorts will be required before deriving generalizable diagnostic or humane-endpoint thresholds.

The nucleolar deubiquitinase OTUD4 coordinates spatial organization of perinucleolar heterochromatin to restrain tumor immunogenicity

Subnuclear compartmentalization is a foundational determinant of transcriptional homeostasis and cell fate. The nucleolus serves as a scaffold for specialized heterochromatin, yet the mechanisms orchestrating their spatial assembly in malignant contexts remain elusive. Here we identify the nucleolar deubiquitinase OTUD4 as a key regulator of perinucleolar heterochromatin architecture in tumor cells. Casein kinase II (CK2)-mediated phosphorylation activates OTUD4 to specifically remove K63-linked ubiquitin chains from nucleophosmin (NPM1) at lysine 27. This deubiquitination is indispensable for stabilizing the pentameric NPM1 structural scaffold, thereby anchoring H3K9me3-marked heterochromatin to nucleolus. Disruption of the CK2–OTUD4–NPM1 axis in tumor cells triggers heterochromatin detachment, eliciting nucleolar stress and retroelement derepression. This topological collapse activates cytosolic DNA-sensing pathways to potentiate tumor-intrinsic immunogenicity. Clinically, an OTUD4-nucleolus gene signature correlates with adverse survival and immunotherapy resistance in patients with cancer. Collectively, targeting this signal-responsive spatial architecture offers a therapeutic strategy to overcome immune evasion in refractory malignancies. Here the authors describe a nucleolar phosphorylation–deubiquitination cascade that regulates perinucleolar heterochromatin organization, showing that loss of OTUD4 in cancer cells induces nucleolar stress and retroelement derepression, restoring DNA sensor-mediated tumor immunogenicity.

Metabolic hallmarks of regulated cell death

Regulated cell death (RCD) is characterized by distinct molecular execution mechanisms, but its initiation, progression, and biological consequences are increasingly recognized as being shaped by cellular metabolism. Bioenergetic state, redox homeostasis, nutrient availability, metal ion metabolism, inflammatory metabolism, and organelle function collectively determine cellular susceptibility to death and influence the activation and execution of diverse RCD programs. In this review, we synthesize the metabolic hallmarks of established, independently validated, and recently proposed forms of RCD, highlighting both their mechanistic diversity and their extensive metabolic convergence. We then examine the endogenous mechanisms that maintain metabolic homeostasis and discuss how their disruption reshapes cell death responses in human disease and therapeutic contexts. Together, these insights provide a guide to the metabolic landscape of RCD and reveal metabolism not only as a modifier of cell death, but as a fundamental determinant of when, how, and with what consequences cells die. We conclude by discussing key conceptual and mechanistic challenges and emerging opportunities for therapeutically exploiting the metabolic control of RCD.

A chemical-genetic system for calreticulin exposure on cancer cells reveals immune-dependent antitumor effects

Premortem exposure of calreticulin (CALR) on stressed cancer cells is a cardinal damage-associated molecular pattern that licenses anticancer immunity, yet its immunological sufficiency has remained difficult to define because it normally coincides with cellular stress and cell death. Here, we engineered a chemical-genetic system enabling the conditional, biotin-driven translocation of a membrane-anchored CALR chimera from the endoplasmic reticulum to the plasma membrane, thereby uncoupling CALR exposure from cytotoxicity and other hallmarks of immunogenic cell death. This reductionist approach revealed that isolated CALR surface presentation is sufficient to promote CD91/LRP1-dependent engulfment of tumor cells by conventional dendritic cells, particularly cDC1 and cDC2, leading to enhanced dendritic cell activation, cytotoxic lymphocyte responses, and immunological memory. Across multiple syngeneic tumor models, enforced CALR exposure exerted modest standalone antitumor activity but robustly sensitized poorly immunogenic cancers to cisplatin and PD-1 blockade, culminating in T cell-dependent tumor eradication and durable protective immunity. Remarkably, concurrent inhibition of the CD47–SIRPα axis facilitated complete tumor eradication in all treated animals, highlighting the functional cooperation between eat-me and don’t-eat-me signals in orchestrating antigen presentation and adaptive immune priming. These findings further suggest that maximizing the therapeutic activity of CD47 blockade may require concomitant reinforcement of pro-phagocytic signals such as CALR exposure, providing a conceptual framework for the rational design of next-generation combination immunotherapies. Collectively, these findings establish surface-exposed CALR as a cell-autonomous immunogenic signal with instructive activity for dendritic cell-mediated cross-priming and provide a tractable platform to mechanistically deconvolute immunogenic stress responses, with immediate implications for the rational design of combinatorial chemo- and immunotherapeutic regimens in preclinical and potentially clinical oncology.

Decline of chaperone-mediated autophagy in aging impairs macrophage clearance of senescent cells

Autophagy dysfunction and senescence are established drivers of aging, but their potential interaction remains poorly understood. Here we show that age-related decline of chaperone-mediated autophagy (CMA), a pathway for selective lysosomal protein degradation, changes senescent cell properties and impairs their immune clearance. CMA-deficient cells undergo senescence but acquire proteomic, metabolic and secretory features resembling those in aged senescent cells. Their senescence-associated secretory phenotype exhibits enhanced pro-senescence effects on neighboring cells and inhibits macrophage CMA, which impairs their ability to engulf senescent cells. Accordingly, blockage of CMA specifically in macrophages increases senescent cell accumulation in mice and delays senescence resolution during wound healing. Conversely, pharmacological CMA activation reduces senescent cell burden in aged mice and disease severity in a pulmonary fibrosis mouse model. Our findings identify CMA decline as a driver of senescent cell persistence and highlight CMA upregulation as a promising strategy to promote senescence resolution in aged organisms. This study looks at how the decline in chaperone-mediated autophagy in aging alters senescent cell properties leading to an impairment in their immune clearance. Utilizing proteomic and metabolomic analyses, the authors show that restoring autophagy enhances macrophage function and reduces senescent cell accumulation.

Chest CT screening identifies ~3% lung cancer prevalence in daily smokers with ASCVD.

May support targeted screening in CVD smokers; extends NLST/NELSON criteria but leaves open need for RCTs.

AUG 22TangCell Death and Differentiation

Cuproptosis: an emerging member of the immunogenic cell death family

Conceptual review highlights cuproptosis as an immunogenic cell death pathway in cancer, suggesting new therapeutic strategies for activating antitumor immune responses.

A higher methyl-NAM/NAM ratio, indicating reduced nicotinamide bioavailability, was associated with a significantly higher risk of cardiovascular death or heart failure progression in HFpEF patients.

Nicotinamide improves obesity-related HFpEF by restoring cardiac autophagy via attenuated IGF-1 signaling, and reduced NAM bioavailability in humans is associated with worse HFpEF outcomes.

Stress management by benzodiazepines in septic shock and critical illness: mechanistic and clinical evidence supporting alternative sedative strategies

Critical care involves the management of organismal stress by sedation. Benzodiazepines remain widely used for anxiolysis and sedation in critical care, including in septic shock. Yet converging mechanistic, preclinical and clinical evidence suggests that benzodiazepines and the endogenous ligand of benzodiazepine-binding sites, the "endozepine" acyl-CoA binding protein/diazepam binding inhibitor (ACBP/DBI), may impair host immune defenses, exacerbate organ dysfunction and contribute to long-term morbidity after intensive care. A unifying framework is that benzodiazepines may accelerate "iatrogenic aging" by antagonizing adaptive stress responses (notably autophagy) and favoring cellular senescence, chronic inflammation, immunosuppression and neurocognitive perturbations. Here, we synthesize evidence supporting benzodiazepine avoidance in sepsis-heavy intensive care populations. We propose that replacing benzodiazepines with alternative sedative strategies may improve both short-term outcomes and long-term trajectories of post-sepsis disability. We hypothesize that post-intensive-care syndrome (PICS), including -as a specific case- post-sepsis syndrome (PSS), is caused by premature aging of the organism and that PICS/PSS might be attenuated by the avoidance of benzodiazepine administration during and after critical care.

JUL 30TangCell Research

Ferroptotic propagation: from single-cell execution to tissue-scale death programs

Perspective integrates ferroptotic contagion mechanisms across distances, suggesting implications for therapy and tissue repair.

Protocol for minimized-bias profiling of liver and visceral adipose tissue in mice using integrated single-nucleus RNA sequencing

Protocol outlines tissue-specific nuclei extraction and enhanced cell-type recovery in mice, suggesting improved profiling accuracy for liver and adipose tissues.

Metabolic determinants of cancer immunotherapy outcomes identified by plasma profiling

Identifies metabolic predictors of survival in cancer patients undergoing immunotherapy, suggesting potential interventions.

Engineered flavonoid disrupts mitochondrial AIF/CHCHD4 complex for targeted cancer therapy

Oncogenic metabolism depends on multifaceted mechanisms, including bidirectional inter-organelle communication between mitochondria and the nucleus, facilitating cellular adaptation at the transcriptomic, proteomic, and metabolomic levels. The mitochondrial protein complex composed of apoptosis-inducing factor (AIF) and coiled-coil-helix-coiled-coil-helix domain-containing protein 4 (CHCHD4) is essential for this mitochondrio-nuclear communication. The AIF/CHCHD4 complex mediates the mitochondrial import of cysteine-enriched nuclear gene-encoded proteins, thereby adapting the mitochondrial proteome to cellular energy demands. We report the discovery of M30-E05, an engineered flavonoid that binds to the NADH pocket of AIF, preventing its dimerization and disrupting the AIF/CHCHD4 complex. Molecular docking and gel electrophoresis analysis of mitochondrial AIF/CHCHD4 substrates expression confirm this mechanism. In cancer cells, M30-E05 reduces the expression of nuclear gene-encoded mitochondrial proteins such as AIF, CHCHD4, COX17, and MICU1. In addition, M30-E05 fragments the mitochondrial network and impairs mitochondrial respiration, causing profound alterations, particularly in lipid and aminoacid metabolism, as revealed by kinetic measurements of oxygen consumption and mass spectrometric metabolomics. Importantly, M30-E05 significantly reduces the viability of a human adult and pediatric osteosarcoma cancer cell panel, including those from patient-derived xenografts (PDX) of osteosarcomas, and induces apoptosis. When orally administered for two weeks to immunodeficient NSG mice, M30-E05 inhibited tumor growth in a subcutaneous PDX xenograft model without apparent toxicity. We anticipate that M30-E05, as a first-in-class metabolic inhibitor, could serve as the lead compound for a new class of targeted antineoplastic agents.

Cell stress and death liberate the autophagy-inhibitory tissue stress hormone DBI/ACBP into the circulation

JUN 2TangCell Death and Differentiation

When vitamins decide life or death

Cell fate decisions have traditionally been interpreted through the lens of genetic programs and signaling cascades. However, increasing evidence places metabolism at the center of life–death determination [ 1 , 2 ]. Among metabolic regulators, vitamins (long regarded as passive nutritional cofactors) are increasingly recognized as active determinants of cellular physiology that couple metabolic state to cell fate. Rather than viewing vitamins solely as metabolic cofactors, this framework positions them as dynamic regulators of the cellular death threshold across systemic, pathway, and molecular levels.

Neutralization of DBI/ACBP for the prevention of ciliopathy-associated obesity

Integrative multi-omics analysis finds that DBI/ACBP neutralization prevents obesity in a mouse model of ciliopathy, suggesting new treatment pathways.

Identification of ACBP as a potential target in ciliopathic obesity through multi-omics network analysis

Multi-omics study reveals that neutralizing ACBP limits weight gain and metabolic defects in Alms1-deficient mice, indicating a potential therapy for ciliopathic obesity.

Association of immune relevant single nucleotide polymorphisms with ALK-positive anaplastic large cell lymphoma presentation and outcome: results of the immuno ALCL study

BACKGROUND: Single nucleotide polymorphisms (SNPs) of cancer-immunity relevant genes may decide the extent of tumor immunosurveillance and have clinical significance. The Immuno ALCL trial was designed to investigate whether genetic variability in 13 cancer-immunity relevant genes correlated with clinical features and outcome of anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) patients. METHODS: One hundred eighty patients were enrolled and genotyped for 14 SNPs. Age at diagnosis, progression-free survival, histological subtype and anti-ALK antibody titer data were collected. RESULTS: IL10 rs1800872, IL10 rs1800896 and TLR3 rs3775291 variants significantly correlated with age at diagnosis. TLR3 rs3775291 was associated with progression-free survival in a recessive model. Combination of multiple genetic variations showed a trend to associate with post-therapeutic relapse. None of the SNP analyzed associated with histological or clinical parameters. CONCLUSION: Despite the low number of patients, our work uncovered potential associations between certain cancer-immunity relevant genes and clinical features of ALK-positive ALCL patients. Associations do not imply causations. However, our work highlighted a possible contribution of the IL10 and TLR3 pathways to ALK-positive ALCL pathogenesis and suggested that several genetic variants in concert may modulate the risk of post-therapeutic relapse. TRIAL REGISTRATION: clinicaltrial.gov NCT02902874. Registered 07 September 2016 https//clinicaltrials.gov/study/NCT02902874.

Exercise attenuates the hallmarks of aging: Novel perspectives

The number and proportion of individuals aged 60 years and older are steadily increasing. However, increased life expectancy is accompanied by a decline in functional capacity and a heightened risk of age-related diseases, ultimately leading to reduced quality of life. Interventions that support physiological function in later life and hence extend healthspan are therefore of considerable importance. Among these, regular physical exercise is strongly associated with numerous health benefits and is recognized as a key strategy for promoting healthy aging and extending healthspan. In this review, we highlight the impact of an active lifestyle, particularly regular physical activity, on the major hallmarks of aging. These include genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, impaired macroautophagy, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, changes in the extracellular matrix, stem cell exhaustion, altered intercellular communication, chronic inflammation, dysbiosis, and psychosocial isolation. A deeper understanding of the mechanisms by which exercise confers these benefits will aid in enhancing both physical and mental health in the elderly and in mitigating the onset of aging-associated diseases.