bims-cagime Biomed News
on Cancer, aging and metabolism
Issue of 2025–01–05
24 papers selected by
Kıvanç Görgülü, Technical University of Munich



  1. J Cell Biol. 2025 Feb 03. pii: e202404047. [Epub ahead of print]224(2):
      Canonical autophagy captures within specialized double-membrane organelles, termed autophagosomes, an array of cytoplasmic components destined for lysosomal degradation. An autophagosome is completed when the growing phagophore undergoes ESCRT-dependent membrane closure, a prerequisite for its subsequent fusion with endolysosomal organelles and degradation of the sequestered cargo. ATG9A, a key integral membrane protein of the autophagy pathway, is best known for its role in the formation and expansion of phagophores. Here, we report a hitherto unappreciated function of mammalian ATG9A in directing autophagosome closure. ATG9A partners with IQGAP1 and key ESCRT-III component CHMP2A to facilitate this final stage in autophagosome formation. Thus, ATG9A is a central hub governing all major aspects of autophagosome membrane biogenesis, from phagophore formation to its closure, and is a unique ATG factor with progressive functionalities affecting the physiological outputs of autophagy.
    DOI:  https://doi.org/10.1083/jcb.202404047
  2. Trends Cancer. 2024 Dec 27. pii: S2405-8033(24)00277-2. [Epub ahead of print]
      Chronic damage following oncogene induction or cancer therapy can produce cellular senescence. Senescent cells not only exit the cell cycle but communicate damage signals to their environment that can trigger immune responses. Recent work has revealed that senescent tumor cells are highly immunogenic, leading to new ways to activate antitumor immunosurveillance and potentiate T cell-directed immunotherapies. However, other studies have determined that heterogeneous senescent stromal cell populations contribute to immunosuppression and tumor progression, sparking the development of senotherapeutics to target senescent cells that evade immune detection. We review current findings that provide deeper insights into the mechanisms contributing to the dichotomous role of senescence in immune modulation and how that can be leveraged for cancer immunotherapy.
    Keywords:  SASP; cancer immunotherapy; senescence; senolytic; senomorphic; tumor immunology
    DOI:  https://doi.org/10.1016/j.trecan.2024.11.010
  3. Cell. 2024 Dec 26. pii: S0092-8674(24)01341-2. [Epub ahead of print]
      Zinc is an essential micronutrient that regulates a wide range of physiological processes, most often through zinc binding to protein cysteine residues. Despite being critical for modulation of protein function, the cysteine sites in the majority of the human proteome that are subject to zinc binding remain undefined. Here, we develop ZnCPT, a deep and quantitative mapping of the zinc-binding cysteine proteome. We define 6,173 zinc-binding cysteines, uncovering protein families across major domains of biology that are subject to constitutive or inducible zinc binding. ZnCPT enables systematic discovery of zinc-regulated structural, enzymatic, and allosteric functional domains. On this basis, we identify 52 cancer genetic dependencies subject to zinc binding and nominate malignancies sensitive to zinc-induced cytotoxicity. We discover a mechanism of zinc regulation over glutathione reductase (GSR), which drives cell death in GSR-dependent lung cancers. We provide ZnCPT as a resource for understanding mechanisms of zinc regulation of protein function.
    Keywords:  GSR; cancer; cysteine proteomics; glutathione reductase; zinc; zinc-binding proteome
    DOI:  https://doi.org/10.1016/j.cell.2024.11.025
  4. Nature. 2025 Jan 01.
      Lung metastases occur in up to 54% of patients with metastatic tumours1,2. Contributing factors to this high frequency include the physical properties of the pulmonary system and a less oxidative environment that may favour the survival of cancer cells3. Moreover, secreted factors from primary tumours alter immune cells and the extracellular matrix of the lung, creating a permissive pre-metastatic environment primed for the arriving cancer cells4,5. Nutrients are also primed during pre-metastatic niche formation6. Yet, whether and how nutrients available in organs in which tumours metastasize confer cancer cells with aggressive traits is mostly undefined. Here we found that pulmonary aspartate triggers a cellular signalling cascade in disseminated cancer cells, resulting in a translational programme that boosts aggressiveness of lung metastases. Specifically, we observe that patients and mice with breast cancer have high concentrations of aspartate in their lung interstitial fluid. This extracellular aspartate activates the ionotropic N-methyl-D-aspartate receptor in cancer cells, which promotes CREB-dependent expression of deoxyhypusine hydroxylase (DOHH). DOHH is essential for hypusination, a post-translational modification that is required for the activity of the non-classical translation initiation factor eIF5A. In turn, a translational programme with TGFβ signalling as a central hub promotes collagen synthesis in lung-disseminated breast cancer cells. We detected key proteins of this mechanism in lung metastases from patients with breast cancer. In summary, we found that aspartate, a classical biosynthesis metabolite, functions in the lung environment as an extracellular signalling molecule to promote aggressiveness of metastases.
    DOI:  https://doi.org/10.1038/s41586-024-08335-7
  5. Cancer Res. 2025 Jan 02.
      Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest solid cancers; thus, identifying more effective therapies is a major unmet need. In this study, we characterized the super enhancer (SE) landscape of human PDAC to identify drivers of the disease that might be targetable. This analysis revealed MICAL2 as a super enhancer-associated gene in human PDAC, which encodes the flavin monooxygenase MICAL2 that induces actin depolymerization and indirectly promotes SRF transcription by modulating the availability of serum response factor coactivators myocardin-related transcription factors (MRTF-A and MRTF-B). MICAL2 was overexpressed in PDAC, and high MICAL2 expression correlated with poor patient prognosis. Transcriptional analysis revealed that MICAL2 upregulates KRAS and EMT signaling pathways, contributing to tumor growth and metastasis. In loss and gain of function experiments in human and mouse PDAC cells, MICAL2 promoted both ERK1/2 and AKT activation. Consistent with its role in actin depolymerization and KRAS signaling, loss of MICAL2 also inhibited macropinocytosis. MICAL2, MRTF-A, and MRTF-B influenced PDAC cell proliferation and migration and promoted cell cycle progression in vitro. Importantly, MICAL2 supported in vivo tumor growth and metastasis. Interestingly, MRTF-B, but not MRTF-A, phenocopied MICAL2-driven phenotypes in vivo. This study highlights the multiple ways in which MICAL2 impacts PDAC biology and provides a foundation for future investigations into the potential of targeting MICAL2 for therapeutic intervention.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-24-0744
  6. Nature. 2025 Jan 01.
      Glioblastoma is an incurable brain malignancy. By the time of clinical diagnosis, these tumours exhibit a degree of genetic and cellular heterogeneity that provides few clues to the mechanisms that initiate and drive gliomagenesis1,2. Here, to explore the early steps in gliomagenesis, we utilized conditional gene deletion and lineage tracing in tumour mouse models, coupled with serial magnetic resonance imaging, to initiate and then closely track tumour formation. We isolated labelled and unlabelled cells at multiple stages-before the first visible abnormality, at the time of the first visible lesion, and then through the stages of tumour growth-and subjected cells of each stage to single-cell profiling. We identify a malignant cell state with a neural crest-like gene expression signature that is highly abundant in the early stages, but relatively diminished in the late stage of tumour growth. Genomic analysis based on the presence of copy number alterations suggests that these neural crest-like states exist as part of a heterogeneous clonal hierarchy that evolves with tumour growth. By exploring the injury response in wounded normal mouse brains, we identify cells with a similar signature that emerge following injury and then disappear over time, suggesting that activation of an injury response program occurs during tumorigenesis. Indeed, our experiments reveal a non-malignant injury-like microenvironment that is initiated in the brain following oncogene activation in cerebral precursor cells. Collectively, our findings provide insight into the early stages of glioblastoma, identifying a unique cell state and an injury response program tied to early tumour formation. These findings have implications for glioblastoma therapies and raise new possibilities for early diagnosis and prevention of disease.
    DOI:  https://doi.org/10.1038/s41586-024-08356-2
  7. Cancer Res. 2025 Jan 02. 85(1): 7-9
      Therapy-exposed surviving cancer cells may have encountered profound epigenetic remodeling that renders these drug-tolerant persisters candidate drivers of particularly aggressive relapses. Typically presenting as slow-to-nongrowing cells, persisters are senescent or senescence-like cells. In this issue of Cancer Research, Ramponi and colleagues study mTOR/PI3K inhibitor-induced embryonic diapause-like arrest (DLA) as a model of persistence in lung cancer and melanoma cells and compare this persister condition with therapy-induced senescence in the same cells. The DLA phenotype recapitulated some but not all features attributed to senescent cells, lacking, for instance, an inflammatory secretome otherwise known as the senescence-associated secretory phenotype. A CRISPR dropout screen pointed to methyl group-providing one-carbon metabolism and further to H4K20me3-mediated repression of senescence-associated secretory phenotype-related IFN response genes selectively in DLA-like persister cells. Conversely, inhibition of H4K20-active KMT5B/C methyltransferases derepressed inflammatory programs and was toxic in DLA cells. These findings not only suggest exploitable vulnerabilities of DLA-like persister cells but also unveil general technical and conceptual challenges of cultured multipassage cell line-based persister studies. Collectively, the approach chosen and insights obtained will stimulate a productive scientific debate on senescence-like features and their reversibility across drug-tolerant persister cells. See related article by Ramponi et al., p. 32.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-24-3744
  8. Trends Cancer. 2024 Dec 27. pii: S2405-8033(24)00275-9. [Epub ahead of print]
      In 1982, the RAS genes HRAS and KRAS were discovered as the first human cancer genes, with KRAS later identified as one of the most frequently mutated oncogenes. Yet, it took nearly 40 years to develop clinically effective inhibitors for RAS-mutant cancers. The discovery in 2013 by Shokat and colleagues of a druggable pocket in KRAS paved the way to FDA approval of the first covalently binding KRASG12C inhibitors, sotorasib and adagrasib, in 2021 and 2022, respectively. However, rather than marking the end of a successful assault on the Mount Everest of cancer research, this landmark only revealed new challenges in RAS drug discovery. In this review, we highlight the progress on defining resistance mechanisms and developing combination treatment strategies to improve patient responses to KRAS therapies.
    Keywords:  KRAS; colorectal carcinoma; drug resistance; non-small cell lung cancer; pancreatic ductal adenocarcinoma
    DOI:  https://doi.org/10.1016/j.trecan.2024.11.009
  9. Mol Cancer. 2025 Jan 02. 24(1): 2
      Metastasis remains a leading cause of cancer-related mortality, irrespective of the primary tumour origin. However, the core gene regulatory program governing distinct stages of metastasis across cancers remains poorly understood. We investigate this through single-cell transcriptome analysis encompassing over two hundred patients with metastatic and non-metastatic tumours across six cancer types. Our analysis revealed a prognostic core gene signature that provides insights into the intricate cellular dynamics and gene regulatory networks driving metastasis progression at the pan-cancer and single-cell level. Notably, the dissection of transcription factor networks active across different stages of metastasis, combined with functional perturbation, identified SP1 and KLF5 as key regulators, acting as drivers and suppressors of metastasis, respectively, at critical steps of this transition across multiple cancer types. Through in vivo and in vitro loss of function of SP1 in cancer cells, we revealed its role in driving cancer cell survival, invasive growth, and metastatic colonisation. Furthermore, tumour cells and the microenvironment increasingly engage in communication through WNT signalling as metastasis progresses, driven by SP1. Further validating these observations, a drug repurposing analysis identified distinct FDA-approved drugs with anti-metastasis properties, including inhibitors of WNT signalling across various cancers.
    Keywords:  Cancer; Gene regulation; Metastasis; Single-cell heterogeneity; Transcription Factors
    DOI:  https://doi.org/10.1186/s12943-024-02182-w
  10. Semin Cancer Biol. 2024 Dec 27. pii: S1044-579X(24)00099-3. [Epub ahead of print]
      Pancreatic ductal adenocarcinoma (PDAC) is the most lethal and common form of pancreatic cancer, it has no specific symptoms, and most of the patients are diagnosed when the disease is already at an advanced stage. Chemotherapy typically has only a modest effect, making surgery the most effective treatment option. However, only a small percentage of patients are amenable to surgery. One viable strategy to reduce PDAC death burden associated with the disease is to focus on precursor lesions and identify markers able to predict who will evolve into PDAC. While most PDACs are believed to be preceded by pancreatic intraepithelial neoplasms (PanINs), 5-10% arise from Intraductal papillary mucinous neoplasms (IPMNs), which are mass-forming cystic lesions that are very common in the general population. IPMNs offer an invaluable model of pancreatic carcinogenesis for researchers to analyse, as well as a target population for PDAC early detection by clinicians. The evolution of IPMN into cancer is a complex and multistep process, therefore the identification of individual markers will not be the solution. In recent years, multiple omics technologies have been instrumental to identify possible biomarkers of IPMN progression and carcinogenesis. The only foreseeable strategy will be to integrate multi-omics data, alongside clinical and morphological features, into a progression score or signature using either standard epidemiologic tools or artificial intelligence. The aim of this manuscript is to review the current knowledge on genetic biomarkers and to briefly mention also additional omics, such as metabolomics, the exposome, the miRNome and epigenomics of IPMNs.
    Keywords:  Intraductal papillary mucinous neoplasm; exposome; metabolomics; microRNA; polymorphisms
    DOI:  https://doi.org/10.1016/j.semcancer.2024.12.005
  11. Autophagy. 2025 Jan 02. 1-21
      Lysosomes are the major cellular organelles responsible for nutrient recycling and degradation of cellular material. Maintenance of lysosomal integrity is essential for cellular homeostasis and lysosomal membrane permeabilization (LMP) sensitizes toward cell death. Damaged lysosomes are repaired or degraded via lysophagy, during which glycans, exposed on ruptured lysosomal membranes, are recognized by galectins leading to K48- and K63-linked poly-ubiquitination (poly-Ub) of lysosomal proteins followed by recruitment of the macroautophagic/autophagic machinery and degradation. Linear (M1) poly-Ub, catalyzed by the linear ubiquitin chain assembly complex (LUBAC) E3 ligase and removed by OTULIN (OTU deubiquitinase with linear linkage specificity) exerts important functions in immune signaling and cell survival, but the role of M1 poly-Ub in lysosomal homeostasis remains unexplored. Here, we demonstrate that L-leucyl-leucine methyl ester (LLOMe)-damaged lysosomes accumulate M1 poly-Ub in an OTULIN- and K63 Ub-dependent manner. LMP-induced M1 poly-Ub at damaged lysosomes contributes to lysosome degradation, recruits the NFKB (nuclear factor kappa B) modulator IKBKG/NEMO and locally activates the inhibitor of NFKB kinase (IKK) complex to trigger NFKB activation. Inhibition of lysosomal degradation enhances LMP- and OTULIN-regulated cell death, indicating pro-survival functions of M1 poly-Ub during LMP and potentially lysophagy. Finally, we demonstrate that M1 poly-Ub also occurs at damaged lysosomes in primary mouse neurons and induced pluripotent stem cell-derived primary human dopaminergic neurons. Our results reveal novel functions of M1 poly-Ub during lysosomal homeostasis, LMP and degradation of damaged lysosomes, with important implications for NFKB signaling, inflammation and cell death.Abbreviation: ATG: autophagy related; BafA1: bafilomycin A1; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CRISPR: clustered regularly interspaced short palindromic repeats; CHUK/IKKA: component of inhibitor of nuclear factor kappa B kinase complex; CUL4A-DDB1-WDFY1: cullin 4A-damage specific DNA binding protein 1-WD repeat and FYVE domain containing 1; DGCs: degradative compartments; DIV: days in vitro; DUB: deubiquitinase/deubiquitinating enzyme; ELDR: endo-lysosomal damage response; ESCRT: endosomal sorting complex required for transport; FBXO27: F-box protein 27; GBM: glioblastoma multiforme; IKBKB/IKKB: inhibitor of nuclear factor kappa B kinase subunit beta; IKBKG/NEMO: inhibitor of nuclear factor kappa B kinase regulatory subunit gamma; IKK: inhibitor of NFKB kinase; iPSC: induced pluripotent stem cell; KBTBD7: kelch repeat and BTB domain containing 7; KO: knockout; LAMP1: lysosomal associated membrane protein 1; LCD: lysosomal cell death; LGALS: galectin; LMP: lysosomal membrane permeabilization; LLOMe: L-leucyl-leucine methyl ester; LOP: loperamide; LUBAC: linear ubiquitin chain assembly complex; LRSAM1: leucine rich repeat and sterile alpha motif containing 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; NBR1: NBR1 autophagy cargo receptor; NFKB/NF-κB: nuclear factor kappa B; NFKBIA/IĸBα: nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha; OPTN: optineurin; ORAS: OTULIN-related autoinflammatory syndrome; OTULIN: OTU deubiquitinase with linear linkage specificity; RING: really interesting new gene; RBR: RING-in-between-RING; PLAA: phospholipase A2 activating protein; RBCK1/HOIL-1: RANBP2-type and C3HC4-type zinc finger containing 1; RNF31/HOIP: ring finger protein 31; SHARPIN: SHANK associated RH domain interactor; SQSTM1/p62: sequestosome 1; SR-SIM: super-resolution-structured illumination microscopy; TAX1BP1: Tax1 binding protein 1; TBK1: TANK binding kinase 1; TH: tyrosine hydroxylase; TNF/TNFα: tumor necrosis factor; TNFRSF1A/TNFR1-SC: TNF receptor superfamily member 1A signaling complex; TRIM16: tripartite motif containing 16; Ub: ubiquitin; UBE2QL1: ubiquitin conjugating enzyme E2 QL1; UBXN6/UBXD1: UBX domain protein 6; VCP/p97: valosin containing protein; WIPI2: WD repeat domain, phosphoinositide interacting 2; YOD1: YOD1 deubiquitinase.
    Keywords:  Cell death; LUBAC; NF-κB; OTULIN; linear ubiquitination; lysosomes
    DOI:  https://doi.org/10.1080/15548627.2024.2443945
  12. Small. 2025 Jan 02. e2405998
      Cancer metastasis involves cell migration from their primary organ foci into vascular channels, followed by dissemination to prospective colonization sites. Vascular entry of tumor cells or intravasation involves their breaching stromal and endothelial extracellular matrix (ECM) and the endothelial barriers. How the kinetics of this breach are confounded by chronic inflammatory stresses seen in diabetes and aging remains ill-investigated. To study the problem, a histopathology-motivated, imaging-tractable, microfluidic multi-organ-on-chip platform is constructed, that seamlessly integrates a breast tumor-like compartment: invasive MDA-MB-231 in a 3D Collagen I scaffold, and a flow-implemented vascular channel: immortalized human aortic endothelia (TeloHAEC) on laminin-rich basement membrane (lrBM). The chip showcases the complexity of intravasation, wherein tumor cells and endothelia cooperate to form anastomotic structures, which facilitate cancer cell migration into the vascular channel. Upon entry, cancer cells adhere to and flow within the vascular channel. Exposure to methylglyoxal (MG), a dicarbonyl stressor associated with diabetic circulatory milieu increases cancer cell intravasation and adhesion through the vascular channel. This can be driven by MG-induced endothelial senescence and shedding, but also by the ability of MG to degrade lrBM and pathologically cross-link Collagen I, diminishing cell-ECM adhesion. Thus, dicarbonyl stress attenuates homeostatic barriers to cancer intravasation, exacerbating metastasis.
    Keywords:  Type 2 diabetes mellitus; breast cancer; disease modeling; intravasation; methylglyoxal; microfluidics; organ‐on‐chip
    DOI:  https://doi.org/10.1002/smll.202405998
  13. Anal Chem. 2025 Jan 01.
      Effective dietary strategies and interventions for monitoring dietary exposures require accurate and noninvasive methods to understand how diet modulates health and risk of obesity; advances in technology are transforming the landscape and enabling more specific tailored approaches to nutritional guidance. This study explores the use of Raman spectroscopy (RS), a noninvasive and nondestructive analytical technique, to identify changes in the mice skin in response to constant dietary exposures. We found that RS is highly accurate to determine body composition as a result of habitual dietary patterns, specifically Vegan, Typical American, and Ketogenic diets, all very common in the US context. RS is based on major differences in the intensities of vibrational bands that originate from collagen. Moreover, RS could be used to predict folate deficiency and identify the sex of the animals. Finally, we found that RS could be used to track the chronological age of the mice. Considering the hand-held nature of the utilized spectrometer, one can expect that RS could be used to monitor and, consequently, personalize effects of diet on the body composition.
    DOI:  https://doi.org/10.1021/acs.analchem.4c05853
  14. Pancreatology. 2024 Dec 17. pii: S1424-3903(24)00836-6. [Epub ahead of print]
       BACKGROUND/OBJECTIVES: The aim of our study was to evaluate if the histopathological changes occurring in the pancreas post neoadjuvant-therapy (PNAT) for pancreatic ductal adenocarcinoma (PDAC) may negatively affect the assessment of intra-operative frozen section (FS) analysis of pancreatic resection margins (PRMs).
    METHODS: The clinicopathological data of patients who underwent pancreatoduodenectomy for PDAC between 2015 and 2022 were analyzed. Comparison of the accuracy of the FS analysis in treatment naïve (TN) and PNAT patients for all pancreatic margins was performed.
    RESULTS: We identified 81 patients with PDAC (40 female, 41 male) of which 47 (58.0 %) were TN and 34 (42.0 %) PNAT. Including FSs performed for re-excisions of initially positive PRMs, we identified 2/103 discrepancies for the pancreatic neck margin, one in a TN patient and one in a PNAT patient; one discrepancy for the common bile duct margin (1/47) in a TN patient; and 2/14 discrepancies for the uncinate margin, both in TN patients. In summary, accuracy of FS analysis was similar in the PNAT and TN groups (98.8 % vs. 96.7 %).
    CONCLUSIONS: The histopathological changes occurring in the pancreas PNAT for PDAC do not affect the histopathological interpretation of FS analysis of PRMs, and the accuracy of FS analysis is similar in the PNAT and TN patients.
    Keywords:  Intraoperative diagnosis; Neoadjuvant treatment; Pancreatic cancer; Pancreatic neck margins; Pathology
    DOI:  https://doi.org/10.1016/j.pan.2024.12.008
  15. Trends Cancer. 2024 Dec 27. pii: S2405-8033(24)00279-6. [Epub ahead of print]
      Metastasis is responsible for most cancer-related deaths. Different cancers have their own preferential sites of metastases, a phenomenon termed metastatic organotropism. The mechanisms underlying organotropism are multifactorial and include the generation of a pre-metastatic niche (PMN), metastatic homing, colonization, dormancy, and metastatic outgrowth. Historically, studies of metastatic organotropism have been limited by a lack of models allowing direct comparison of cells exhibiting different patterns of tropism. However, new innovative models and large-scale sequencing efforts have propelled organotropism research. Herein, we summarize the recent discoveries in metastatic organotropism regulation, focusing on lung, liver, brain, and bone tropism. We discuss how emerging technologies are continuing to improve our ability to model and, hopefully, predict and treat organotropism.
    Keywords:  circulatory tumor cells; metastasis; metastatic homing; modeling systems; organotropism; pre-metastatic niche
    DOI:  https://doi.org/10.1016/j.trecan.2024.11.012
  16. ACS Omega. 2024 Dec 24. 9(51): 50458-50465
      Electroporation ablation is a minimally invasive nonthermal ablation technology that is applied to tumor ablation therapy. Given the varied morphologies of tumor cells, when an electric field is applied to the cell membrane surface, the direction of the electric field produces various angles with normal to the tangential plane of the cell membrane. In this study, we investigated the impact of cell morphology on membrane electroporation characteristics by adjusting the angle of the electric field relative to the cell membrane by using molecular dynamics simulations. The results show that the bidirectional modulation of cell membrane surface tension induced by Coulomb force can be triggered, allowing the electroporation effect to be regulated, by varying the angle between the electric field direction and the normal to the membrane. Electric field angles below 45° decreased phospholipid membrane surface tension, facilitating pore formation; angles above 45° enhanced the surface tension, elevating the energy barrier for pore opening and thus inhibiting pore formation. Furthermore, during the initial stage of membrane pore formation, water molecules penetrated the lipids, which aligned with the electric field and affected the pore tilt. The bidirectional modulation of the electric field in electroporation demonstrated that reversing the angle of the electric field is a potentially effective electroporation ablation protocol for improving the effectiveness of clinical cancer treatments.
    DOI:  https://doi.org/10.1021/acsomega.4c07396
  17. Mol Metab. 2024 Dec 28. pii: S2212-8778(24)00220-5. [Epub ahead of print] 102089
      Cellular metabolism plays a pivotal role in the development and progression of pancreatic ductal adenocarcinoma (PDAC), with dysregulated metabolic pathways contributing to tumorigenesis and therapeutic resistance. Distinct metabolic heterogeneity exists in pancreatic cancer, impacting patient prognosis, as variations in metabolic profiles influence tumor behavior and treatment responses. Here, we review the intricate interplay between mitochondrial dynamics, mitophagy, and cellular metabolism in PDAC. We highlight the significance of mitophagy dysregulation in PDAC pathogenesis, impacting treatment response and prognosis. Additionally, we examine the impact of mitochondrial dynamics alterations on PDAC progression, focusing on the role of fission and fusion processes in tumorigenesis. Ongoing trials have demonstrated the potential therapeutic value of targeting key regulators of mitochondrial dynamics and mitophagy. Despite challenges, targeting mitochondrial metabolism offers diverse strategies to enhance PDAC treatment efficacy, underscoring its potential in advancing cancer therapeutics.
    Keywords:  Metabolism; Mitochondria; Mitophagy; Oxidative phosphorylation; Pancreatic cancer
    DOI:  https://doi.org/10.1016/j.molmet.2024.102089
  18. Sci Rep. 2024 Dec 28. 14(1): 31348
      Despite decades of improvements in cytotoxic therapy, the current standard of care for locally advanced pancreatic cancer (LAPC) provides, on average, only a few months of survival benefit. Stereotactic Body Radiation Therapy (SBRT), a technique that accurately delivers high doses of radiation to tumors in fewer fractions, has emerged as a promising therapy to improve local control of LAPC; however, its effects on the tumor microenvironment and hypoxia remain poorly understood. To explore how SBRT affects pancreatic tumors, we combined an orthotopic mouse model of pancreatic cancer with an intravital microscopy platform to visualize changes to the in vivo tumor microenvironment in real-time. Mice received SBRT (5 × 8 Gy) or were left untreated, and were imaged before and 1, 4, 7, and 14 days after treatment (n = 7/group). A fluorescent human pancreatic cancer cell line (BxPC3-DsRed) engineered to express GFP under hypoxic conditions (driven by hypoxia-inducible factor, HIF) was used to monitor tumor hypoxia. Immunohistochemical staining was also performed on tissues to validate in vivo data. Our findings demonstrate a persistent decrease in pancreatic tumor hypoxia as early as one day after SBRT. This coincided with a decrease in both tumor cell proliferation and cell density in the SBRT group. Reduced demand for oxygen after SBRT (due to cell death and growth arrest from treatment) significantly contributed to reoxygenation of the pancreatic TME. Understanding how this reoxygenation phenomenon occurs in a dose-dependent manner will help improve dosing and fractionation schemes for clinical SBRT.
    DOI:  https://doi.org/10.1038/s41598-024-82757-1
  19. Nat Commun. 2025 Jan 02. 16(1): 117
      Excitable systems of eukaryotic chemotaxis can generate asymmetric signals of Ras-GTP-enriched domains spontaneously to drive random cell migration without guidance cues. However, the molecules responsible for the spontaneous signal generation remain elusive. Here, we characterized RasGEFs encoded in Dictyostelium discoideum by live-cell imaging of the spatiotemporal dynamics of Ras-GTP and hierarchical clustering, finding that RasGEFX is primarily required for the spontaneous generation of Ras-GTP-enriched domains and is essential for random migration in combination with RasGEFB/M/U in starved cells, and they are dispensable for chemotaxis to chemoattractant cAMP. RasGEFX and RasGEFB that co-localize with Ras-GTP regulate the temporal periods and spatial sizes of the oscillatory Ras-GTP waves propagating along the membrane, respectively, and thus control the protrusions of motile cells differently, while RasGEFU and RasGEFM regulate adhesion and migration speed, respectively. Remarkably, RasGEFX is also important for Ras/PIP3-driven macropinocytosis in proliferating cells, but RasGEFB/M/U are not. These findings illustrate a specific and coordinated control of the cytoskeletal dynamics by multiple RasGEFs for spontaneous motility and macropinocytosis.
    DOI:  https://doi.org/10.1038/s41467-024-55389-2
  20. Nat Commun. 2025 Jan 02. 16(1): 91
      Propagation of membrane tension mediates mechanical signal transduction along surfaces of live cells and sets the time scale of mechanical equilibration of cell membranes. Recent studies in several cell types and under different conditions revealed a strikingly wide variation range of the tension propagation speeds including extremely low ones. The latter suggests a possibility of long-living inhomogeneities of membrane tension crucially affecting mechano-sensitive membrane processes. Here, we propose, analyze theoretically, and support experimentally a mechanism of tension propagation in membranes crumpled by the contractile cortical cytoskeleton. The tension spreading is mediated by the membrane flow between the crumples. We predict the pace of the tension propagation to be controlled by the intra-cellular pressure and the degree of the membrane crumpling. We provide experimental support for the suggested mechanism by monitoring the rate of tension propagation in cells exposed to external media of different osmolarities.
    DOI:  https://doi.org/10.1038/s41467-024-55398-1
  21. Signal Transduct Target Ther. 2025 Jan 03. 10(1): 2
      Rampant phospholipid peroxidation initiated by iron causes ferroptosis unless this is restrained by cellular defences. Ferroptosis is increasingly implicated in a host of diseases, and unlike other cell death programs the physiological initiation of ferroptosis is conceived to occur not by an endogenous executioner, but by the withdrawal of cellular guardians that otherwise constantly oppose ferroptosis induction. Here, we profile key ferroptotic defence strategies including iron regulation, phospholipid modulation and enzymes and metabolite systems: glutathione reductase (GR), Ferroptosis suppressor protein 1 (FSP1), NAD(P)H Quinone Dehydrogenase 1 (NQO1), Dihydrofolate reductase (DHFR), retinal reductases and retinal dehydrogenases (RDH) and thioredoxin reductases (TR). A common thread uniting all key enzymes and metabolites that combat lipid peroxidation during ferroptosis is a dependence on a key cellular reductant, nicotinamide adenine dinucleotide phosphate (NADPH). We will outline how cells control central carbon metabolism to produce NADPH and necessary precursors to defend against ferroptosis. Subsequently we will discuss evidence for ferroptosis and NADPH dysregulation in different disease contexts including glucose-6-phosphate dehydrogenase deficiency, cancer and neurodegeneration. Finally, we discuss several anti-ferroptosis therapeutic strategies spanning the use of radical trapping agents, iron modulation and glutathione dependent redox support and highlight the current landscape of clinical trials focusing on ferroptosis.
    DOI:  https://doi.org/10.1038/s41392-024-02088-5
  22. Proc Natl Acad Sci U S A. 2025 Jan 07. 122(1): e2409596121
      Spns1 mediates the rate-limiting efflux of lysophospholipids from the lysosome to the cytosol. Deficiency of Spns1 is associated with embryonic senescence, as well as liver and skeletal muscle atrophy in animal models. However, the mechanisms by which Spns1 transports lysophospholipid and proton sensing remain unclear. Here, we present a cryogenic electron microscopy structure of human Spns1 in lysophosphatidylcholine (LPC)-bound lumen-facing conformation. Notably, LPC snugly binds within the luminal-open cavity, where the molecular dynamics simulations reveal that LPC presents a propensity to enter between transmembrane-helices (TM) 5 and 8. Structural comparisons and cell-based transport assays uncover several pivotal residues at TM 5/8 that orchestrate the transport cycle, which are unique to Spns1. Furthermore, we identify a five-residue network that is crucial for proton-sensing by Spns1. Transference of these network residues to Spns2, a sphingosine-1-phosphate uniporter, causes the chimeric Spns2 to be low pH dependent. Our results reveal molecular insights into lysosomal LPC transport and the proton-sensing mechanism by Spns1.
    Keywords:  cryo-EM; lysophospholipids; proton-sensing; transporter
    DOI:  https://doi.org/10.1073/pnas.2409596121
  23. Nature. 2025 Jan 01.
    Liver Cancer Collaborative
      Hepatocellular carcinoma (HCC) originates from differentiated hepatocytes undergoing compensatory proliferation in livers damaged by viruses or metabolic-dysfunction-associated steatohepatitis (MASH)1. While increasing HCC risk2, MASH triggers p53-dependent hepatocyte senescence3, which we found to parallel hypernutrition-induced DNA breaks. How this tumour-suppressive response is bypassed to license oncogenic mutagenesis and enable HCC evolution was previously unclear. Here we identified the gluconeogenic enzyme fructose-1,6-bisphosphatase 1 (FBP1) as a p53 target that is elevated in senescent-like MASH hepatocytes but suppressed through promoter hypermethylation and proteasomal degradation in most human HCCs. FBP1 first declines in metabolically stressed premalignant disease-associated hepatocytes and HCC progenitor cells4,5, paralleling the protumorigenic activation of AKT and NRF2. By accelerating FBP1 and p53 degradation, AKT and NRF2 enhance the proliferation and metabolic activity of previously senescent HCC progenitors. The senescence-reversing and proliferation-supportive NRF2-FBP1-AKT-p53 metabolic switch, operative in mice and humans, also enhances the accumulation of DNA-damage-induced somatic mutations needed for MASH-to-HCC progression.
    DOI:  https://doi.org/10.1038/s41586-024-08317-9